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変形性膝関節症

著者: 川﨑展 産業医科大学 整形外科学教室

監修: 酒井昭典 産業医科大学 整形外科学教室

著者校正/監修レビュー済:2022/10/26
参考ガイドライン:
  1. 日本理学療法士協会:変形性膝関節症 理学療法診療ガイドライン
  1. 慢性疼痛診療ガイドライン作成ワーキンググループ:慢性疼痛診療ガイドライン、2021
  1. 慢性疼痛治療ガイドライン作成ワーキンググループ:慢性疼痛治療ガイドライン、2018
  1. 日本整形外科学会:変形性膝関節症の管理に関するOARSI勧告 OARSIによるエビデンスに基づくエキスパートコンセンサスガイドライン(日本整形外科学会変形性膝関節症診療ガイドライン策定委員会による適合化終了版) 第2版
  1. Osteoarthritis Research Society International :OARSI guidelines for the non-surgical management of knee, hip, and polyarticular osteoarthritis
患者向け説明資料

概要・推奨   

  1. 変形性膝関節症は、関節軟骨に退行性変化および変性が起こり、関節軟骨の破壊、骨棘の形成などの骨増殖性変化を伴い、関節の痛み、こわばり、可動域制限および関節の形態学的変化を起こす進行性の疾患である。
  1. 変形性膝関節症は、性別では女性に多く、肥満、糖尿病などのメタボリック症候群や認知障害の存在がリスク因子となりえるため、基礎疾患の予防および治療が重要である。
  1. 座位からの立ち上がり、歩行時、階段昇降時に疼痛が誘発される。進行し、関節腫脹が強い場合には、夜間痛などの安静時痛も見られるため、診察時に問診および観察する。
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薬剤監修について:
オーダー内の薬剤用量は日本医科大学付属病院 薬剤部 部長 伊勢雄也 以下、林太祐、渡邉裕次、井ノ口岳洋、梅田将光による疑義照会のプロセスを実施、疑義照会の対象については著者の方による再確認を実施しております。
※薬剤中分類、用法、同効薬、診療報酬は、エルゼビアが独自に作成した薬剤情報であり、 著者により作成された情報ではありません。
尚、用法は添付文書より、同効薬は、薬剤師監修のもとで作成しております。
※同効薬・小児・妊娠および授乳中の注意事項等は、海外の情報も掲載しており、日本の医療事情に適応しない場合があります。
※薬剤情報の(適外/適内/⽤量内/⽤量外/㊜)等の表記は、エルゼビアジャパン編集部によって記載日時にレセプトチェックソフトなどで確認し作成しております。ただし、これらの記載は、実際の保険適応の査定において保険適応及び保険適応外と判断されることを保証するものではありません。また、検査薬、輸液、血液製剤、全身麻酔薬、抗癌剤等の薬剤は保険適応の記載の一部を割愛させていただいています。
(詳細はこちらを参照)
著者のCOI(Conflicts of Interest)開示:
川﨑展 : 未申告[2022年]
監修:酒井昭典 : 特に申告事項無し[2022年]

改訂のポイント:
  1. 参考ガイドラインをもとに全面的に改訂を行った

病態・疫学・診察

疾患情報(疫学・病態)  
疫学:
  1. 内閣府の発表によれば、2022年現在、65歳以上の高齢者人口は3618万人を超え、総人口に占める割合は28.8%となった[1]
  1. 変形性膝関節症は、長期間の膝関節への負荷により起こる疾患であり、高齢者の運動器の疼痛や機能障害の原因となり、日常生活動作(ADL)を障害し、生活の質(QOL)を低下させ、要介護および要支援の原因となりえる。
  1. 2019年国民生活基礎調査[2]によれば、関節疾患は要支援の原因疾患の第1位(18.9%)であり、その主要疾患である変形性膝関節症は、健康寿命を短縮し、社会的に労働力の低下および医療経済の損失といった事態をもたらしている。
  1. 2005年より3040人の地域住民を対象として大規模住民コホートを行っている研究Research on Osteroarthritis / Osteoporosis Against Disability(ROAD)によれば、立位膝X線像でKellgren-Lawrence (K-L)分類[3]でgrade 2以上を変形性膝関節症ありと判断した場合、その有病率は54.6 %(男性42 %, 女性61.5 %)であった[4]。このデータから推測される我が国のX線上の変形性膝関節症の患者数は2530万人(男性860万人、女性1670万人)となる。
  1. また、K-L分類で0もしくは1であった1098人を追跡(平均追跡期間3.3年)し、K-L分類Grade 2以上に進行したとされるものを新規発生と定義すると、変形性膝関節症の累積年間発生率は2.9 %とされ、これから推測される変形性膝関節症の年間発症者数は190万人(男性50万人、女性140万人)と想定される[5]
  1. また、同調査では、メタボリック症候群の原因で、高血圧の存在は、将来の変形性膝関節症の発症リスクを2.48倍、耐糖能異常の存在は1.92倍に、さらに軽度認知障害の存在は4.19倍に上昇させることが報告されている[6]
  1. 1997年から2007年にわたって行われた三重県宮川村の65歳以上住民598人を対象とした宮川研究では、X線上の明確な変形性膝関節症の有病率は30 %であり、症候性変形性膝関節症の有病率は21.2 %(男性 10.7 %、女性 26.7 %)であった。
  1. 女性、高年齢および肥満が、X線上の変形性膝関節症に関与し、リスク因子であることを報告している[7]
  1. さらに、新潟県松代町で40~65歳の住民1844人を対象とした松代膝健診では、1979年以来3〜7年間隔で縦断調査を行い、変形性膝関節症の自然経過を観察し、発症と進行に影響する機械的因子を調べている。その結果、日本人に多い内側型変形性膝関節症において、歩行立脚時に膝が外側に膨らみ内反し、遊脚期には内反が消失し元に戻る、いわゆる膝thrust(スラスト)の出現と、体脂肪率、大腿四頭筋力等が変形性膝関節症の発症と進行に関与することを報告している[8]
  1. 以上、疫学研究では、日本は人口の約20~30 %において、潜在的に変形性膝関節症が存在し、性別では女性に多く、肥満、糖尿病などのメタボリック症候群や認知障害の存在がリスク因子となり、機能的には、膝スラストの出現および大腿四頭筋力の低下が、その進行に関与するといえる。
 
病態:
  1. 変形性膝関節症は、関節を構成する軟骨に退行変性が起こり、破壊、関節周囲への骨棘形成などの増殖性変化をきたし、関節の痛み、水腫、こわばり、可動域制限などの症状を呈し、形態変化、主に内反変形を起こす進行性の疾患である<図表> <図表>
  1. 元々の内因的なアライメントに加え、身体の加齢による生理的な変化に、個々の活動性、体重過多、過重負荷などの外的要因が加わり、初期の変化として軟骨の変性、滑膜炎、半月板変性および骨髄内炎症性変化が生じ、そこに不安定性が加わり、軟骨損傷の悪循環が生じ、変形性膝関節症が発症するものと考えられる。特に一次性の変形性膝関節症において、アジア人は、蹲踞の姿勢や正座が生活様式に取り入れられるため、その発症に関与しているとの報告がある[9]。また、二次性の変形性膝関節症の原因としては、前十字靱帯損傷などの外傷の既往が重要で、不安定性からその発症に起因する[10]
  1. 病理学的には、病期の進行に伴い、軟骨細胞外基質構成成分のプロテオグリカン、コラーゲンおよびヒアルロン酸などが破壊および遊離し、二次的に滑膜炎を起こし、関節周囲の骨増殖性変化を生じ、関節破壊に至ると考えられている。
 
症状:
  1. 疼痛;
  1. 安静時痛よりも運動時痛を主訴とする。座位からの立ち上がり、歩行時、階段昇降時に疼痛が誘発される。進行し、関節腫脹が強い場合には、夜間痛などの安静時痛も見られる。圧痛は、内側型変形性膝関節症の場合、内側大腿脛骨関節裂隙から大腿骨内側顆部にかけて認められる。圧痛部位は、Pain drawingにおけるエリア4に認め、外側型変形性膝関節症の場合は、エリア8に認める<図表>
  1. 腫脹;
  1. 変形性膝関節症が進行すると、関節液の貯留および滑膜の増殖を認める。水腫により関節内圧が上昇し、疼痛が増悪する。水腫の性状は、粘稠度が高く、黄色透明の性状を示し、時にdebrisと呼ばれる軟骨片の浮遊が見られる<図表>
  1. 可動域制限;
  1. 病期の初期には認めることは少ないが、進行するに伴い、可動域制限が出現する。病期が進行すると完全伸展が不能となる屈曲拘縮が出現する。時に、変性断裂した半月板や、増殖した滑膜ひだ、軟骨片の遊離体が関節に挟まると嵌頓症状を呈することがある。
  1. 変形;
  1. 我が国では内反変形(O脚変形)を呈することが多い<図表>。内反変形は荷重軸の内側移動を起こし、さらに内側の大腿脛骨関節面に力学的負荷が集中し、変形が進行するという悪循環をもたらす。外反変形は少ないが、<図表>に示すような右内反変形と左外反変形が混在する、いわゆるWindswept変形を認めることがあり、その場合、股関節の病態(この場合、左変形性股関節症による内転拘縮)から生じる膝関節の二次性の変形のため、その病態を観察することが重要である。
  1. 筋力低下および不安定性;
  1. 疼痛による廃用症候群が加わり、大腿四頭筋力(特に内側広筋)の低下が起こる。筋力が落ちると、内外反の動揺性も出現し、歩行サイクルの立脚期に内外反変形が増大する膝スラストが出現する。
 
問診・診察のポイント  
問診:
  1. 誘因および発症時期の確認を行う。

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文献 

J H KELLGREN, J S LAWRENCE
Radiological assessment of osteo-arthrosis.
Ann Rheum Dis. 1957 Dec;16(4):494-502.
Abstract/Text
PMID 13498604
Noriko Yoshimura, Shigeyuki Muraki, Hiroyuki Oka, Akihiko Mabuchi, Yoshio En-Yo, Munehito Yoshida, Akihiko Saika, Hideyo Yoshida, Takao Suzuki, Seizo Yamamoto, Hideaki Ishibashi, Hiroshi Kawaguchi, Kozo Nakamura, Toru Akune
Prevalence of knee osteoarthritis, lumbar spondylosis, and osteoporosis in Japanese men and women: the research on osteoarthritis/osteoporosis against disability study.
J Bone Miner Metab. 2009;27(5):620-8. doi: 10.1007/s00774-009-0080-8. Epub 2009 Jul 1.
Abstract/Text Musculoskeletal diseases, especially osteoarthritis (OA) and osteoporosis (OP), impair activities of daily life (ADL) and quality of life (QOL) in the elderly. Although preventive strategies for these diseases are urgently required in an aging society, epidemiological data on these diseases are scant. To clarify the prevalence of knee osteoarthritis (KOA), lumbar spondylosis (LS), and osteoporosis (OP) in Japan, and estimate the number of people with these diseases, we started a large-scale population-based cohort study entitled research on osteoarthritis/osteoporosis against disability (ROAD) in 2005. This study involved the collection of clinical information from three cohorts composed of participants located in urban, mountainous, and coastal areas. KOA and LS were radiographically defined as a grade of > or =2 by the Kellgren-Lawrence scale; OP was defined by the criteria of the Japanese Society for Bone and Mineral Research. The 3,040 participants in total were divided into six groups based on their age: < or =39, 40-49, 50-59, 60-69, 70-79, and > or =80 years. The prevalence of KOA in the age groups < or =39, 40-49, 50-59, 60-69, 70-79, and > or =80 years 0, 9.1, 24.3, 35.2, 48.2, and 51.6%, respectively, in men, and the prevalence in women of the same age groups was 3.2, 11.4, 30.3, 57.1, 71.9, and 80.7%, respectively. With respect to the age groups, the prevalence of LS was 14.3, 45.5, 72.9, 74.6, 85.3, and 90.1% in men, and 9.7, 28.6, 41.7, 55.4, 75.1, and 78.2% in women, respectively. Data of the prevalence of OP at the lumbar spine and femoral neck were also obtained. The estimated number of patients with KOA, LS, and L2-L4 and femoral neck OP in Japan was approximately 25, 38, 6.4, and 11 million, respectively. In summary, we estimated the prevalence of OA and OP, and the number of people affected with these diseases in Japan. The ROAD study will elucidate epidemiological evidence concerning determinants of bone and joint disease.

PMID 19568689
Shigeyuki Muraki, Toru Akune, Hiroyuki Oka, Yuyu Ishimoto, Keiji Nagata, Munehito Yoshida, Fumiaki Tokimura, Kozo Nakamura, Hiroshi Kawaguchi, Noriko Yoshimura
Incidence and risk factors for radiographic knee osteoarthritis and knee pain in Japanese men and women: a longitudinal population-based cohort study.
Arthritis Rheum. 2012 May;64(5):1447-56. doi: 10.1002/art.33508.
Abstract/Text OBJECTIVE: To examine the incidence and progression of radiographic knee osteoarthritis (OA) and the incidence of knee pain, and their risk factors in Japan, using the large-scale population of the nationwide cohort study ROAD (Research on Osteoarthritis/osteoporosis Against Disability).
METHODS: Subjects from the ROAD study who had been recruited in 2005-2007 were followed up with knee radiography 3 years later. A total of 2,262 paired radiographs (74.4% of the original sample) were scored using the Kellgren/Lawrence (K/L) grading system, and the incidence and progression rate of knee OA was examined. The incidence rate of knee pain was also examined. In addition, risk factors were tested for their association with incident and progressive radiographic knee OA and incident knee pain.
RESULTS: Given the ∼3.3-year followup, the rate of incident K/L grade ≥2 radiographic knee OA was 6.9% and 11.9% in men and women, respectively, while that of K/L grade ≥3 knee OA was 8.4% and 13.9% in men and women, respectively. The rate of progressive knee OA was 17.8% and 22.3% in men and women, respectively. The incident rate of knee pain was 21.2% and 27.3% in men and women, respectively. Female sex was a risk factor for incident K/L grade ≥2 knee OA, but was not associated with incident K/L grade ≥3 knee OA or progressive knee OA. Knee pain was a risk factor for incident and progressive knee OA. Previous knee injury was a risk factor for knee pain but not for radiographic knee OA.
CONCLUSION: The present longitudinal study revealed a high incidence of radiographic knee OA in Japan.

Copyright © 2012 by the American College of Rheumatology.
PMID 22135156
Noriko Yoshimura, Shigeyuki Muraki, Kozo Nakamura, Sakae Tanaka
Epidemiology of the locomotive syndrome: The research on osteoarthritis/osteoporosis against disability study 2005-2015.
Mod Rheumatol. 2017 Jan;27(1):1-7. doi: 10.1080/14397595.2016.1226471.
Abstract/Text Although locomotive organ disorders are major causes of disability and require support, little information is available regarding their epidemiology. Prevalence and co-existence of locomotive organ disorders including knee osteoarthritis (KOA), lumbar spondylosis (LS), hip osteoarthritis, and osteoporosis have been determined from baseline results of the Research on Osteoarthritis/Osteoporosis Against Disability (ROAD) study. KOA, LS, and hip osteoarthritis overlap in the population, while KOA and LS co-exist in 42.0% of people. Mutual associations between locomotive organ disorders, metabolic syndrome components, and mild cognitive impairment were found using baseline and 3-year follow-up data from the ROAD study. Logistic regression analysis showed that hypertension, impaired glucose tolerance, and mild cognitive impairment increase the risk of KOA. Osteoporosis at L2-4 was significantly influenced by the presence of femoral neck osteoporosis, and vice versa. In turn, excess weight was inversely associated with the occurrence of femoral neck osteoporosis. Finally, data from the 3rd survey (7-year follow-up) were used to calculate the prevalence of the locomotive syndrome using tests proposed by the Japanese Orthopaedic Association for assessing the risk of developing locomotive syndrome. Subsequently, the age-sex prevalence of stage 1 and stage 2 locomotive syndrome was estimated at 69.8% and 25.1%, respectively.

PMID 27538793
Akihiro Sudo, Noriki Miyamoto, Kazuhiro Horikawa, Masao Urawa, Toru Yamakawa, Tomomi Yamada, Atsumasa Uchida
Prevalence and risk factors for knee osteoarthritis in elderly Japanese men and women.
J Orthop Sci. 2008 Sep;13(5):413-8. doi: 10.1007/s00776-008-1254-2. Epub 2008 Oct 9.
Abstract/Text BACKGROUND: The aims of the present study were to examine the prevalence and risk factors for knee osteoarthritis in elderly Japanese men and women.
METHODS: We examined 598 of the 1513 inhabitants of Miyagawa village aged > or = 65 years (393 women, 205 men). Baseline data, obtained with standard questionnaires, included information on age, past history, sports activity, working, knee pain, smoking, and intakes of alcohol and milk. Bone mineral density of the forearm was measured using dual energy X-ray absorptiometry. Anteroposterior radiographs of both knees were graded for osteoarthritis using the Kellgren-Lawrence grading system. Definite osteoarthritis was defined as a grade of 2 or higher. We used logistic regression analysis by the stepwise method to determine the risk factors for radiographic knee osteoarthritis.
RESULTS: The prevalence of definite radiographic knee osteoarthritis was 30.0% overall: 17.7% in men and 36.5% in women. The prevalence of symptomatic knee osteoarthritis was 21.2% overall: 10.7% in men and 26.7% in women. There were significant differences in the risk of radiographic knee osteoarthritis with body mass index (BMI), sex, age, and bone mineral density (BMD).
CONCLUSIONS: The prevalence of definite radiographic knee osteoarthritis was 30.0% and that of symptomatic knee osteoarthritis was 21.2%. We found that higher BMI, female sex, older age, and higher BMD were significantly associated with an increased risk for radiographic knee osteoarthritis.

PMID 18843454
Go Omori, Kentaro Narumi, Katsutoshi Nishino, Atsushi Nawata, Hiroshi Watanabe, Masaei Tanaka, Kazuo Endoh, Yoshio Koga
Association of mechanical factors with medial knee osteoarthritis: A cross-sectional study from Matsudai Knee Osteoarthritis Survey.
J Orthop Sci. 2016 Jul;21(4):463-468. doi: 10.1016/j.jos.2016.03.006. Epub 2016 Apr 14.
Abstract/Text BACKGROUND: Knee osteoarthritis (OA) is a multifactorial disease that is affected by mechanical factors. The aim of present study was to investigate the association between multiple mechanical factors and medial knee OA in a large epidemiological cohort.
METHODS: Six hundred and ninety-nine subjects (323 males and 376 females), participating in the Matsudai Knee Osteoarthritis Survey 2010, were included. Twelve mechanical factors were selected and their association with the radiographic grade of knee OA, the Western Ontario and McMaster University Index (WOMAC) pain score, and the WOMAC function score was evaluated.
RESULTS: A logistic regression analysis identified varus thrust to be associated with the radiographic grade of knee OA in males (OR: 1.876, 95% CI: 1.332-2.663) and females (2.61, 1.922-3.542), the WOMAC pain score in males (1.997, 1.463-2.672), and the WOMAC function score in females (1.449, 1.12-1.874). Quadriceps muscle strength was associated with the radiographic OA grade in males (0.605, 0.399-0.917) and females (0.636, 0.469-0.863), the WOMAC pain score in females (0.537, 0.445-0.789), and the WOMAC function score in males (0.581, 0.44-0.766). The knee flexion angle was also associated with the radiographic OA grade in males (0.344, 0.19-0.621) and females (0.121, 0.022-0.653), and the WOMAC pain score in males (0.287, 0.156-0.53) and females (0.537, 0.336-0.859). Obesity was associated with the radiographic OA grade in males (1.543, 1.041-2.287) and females (1.589, 1.176-2.146), the WOMAC pain score in female (2.017, 1.517-2.68). Femolo-tibial angle had no significant association with the radiographic knee OA grade or with the WOMAC pain and function scores.
CONCLUSION: Among patients with medial knee OA, dynamic mechanical factors, such as varus thrust, quadriceps muscle strength, and range of motion were more likely to be associated with the radiographic grade of knee OA and to be the WOMAC pain and function scores, compared to static mechanical factors.

Copyright © 2016 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.
PMID 27151074
Yuqing Zhang, David J Hunter, Michael C Nevitt, Ling Xu, Jingbo Niu, Li-Yung Lui, Wei Yu, Piran Aliabadi, David T Felson
Association of squatting with increased prevalence of radiographic tibiofemoral knee osteoarthritis: the Beijing Osteoarthritis Study.
Arthritis Rheum. 2004 Apr;50(4):1187-92. doi: 10.1002/art.20127.
Abstract/Text OBJECTIVE: To examine the association between squatting, a common daily posture in China, and the prevalence of radiographic osteoarthritis (OA) in different knee compartments among Chinese subjects from Beijing, and to estimate how much of the difference in prevalence of knee OA between Chinese subjects in Beijing and white subjects in Framingham, Massachusetts is accounted for by the impact of squatting.
METHODS: We recruited a random sample of Beijing residents age > or =60 years. Subjects answered questions on joint symptoms, and knee radiographs were obtained. Subjects were also asked to recall the average amount of time spent squatting each day at age 25 years. Radiographic films (weight-bearing anteroposterior and skyline views) were read for Kellgren/Lawrence (K/L) grade and individual radiographic features. Medial disease was defined when radiographs showed a K/L grade of > or =2 at the tibiofemoral joint and a medial joint space narrowing score of > or =1, and lateral disease was assessed in a comparable manner in the lateral compartments. We examined the association of squatting with the prevalence of tibiofemoral OA as well as with the prevalence of patellofemoral knee OA, while adjusting for age and other potential confounding factors. We used the same approach to assess the relationship between squatting and tibiofemoral OA in the medial compartment and in the lateral compartment. Finally, we estimated the impact of squatting at age 25 on the difference in prevalence of knee OA between Chinese subjects in Beijing and white subjects in the Framingham OA Study.
RESULTS: Squatting was very common among the Chinese subjects: approximately 40% of men and approximately 68% of women reported squatting > or =1 hour per day at age 25. The prevalence of tibiofemoral OA increased as the time spent squatting at age 25 increased in both the men and the women. Compared with subjects who squatted <30 minutes per day at age 25, the multivariable-adjusted prevalence odds ratios of tibiofemoral OA were 1.1 for time spent squatting of 30-59 minutes/day, 1.0 for 60-119 minutes/day, 1.7 for 120-179 minutes/day, and 2.0 for > or =120 minutes/day among the men (P for trend = 0.074), and the respective odds ratios among the women were 1.4, 1.3, 1.2, and 2.4 (P for trend = 0.077). A weaker association with patellofemoral OA was found. Prolonged squatting in daily life was more strongly associated with medial knee OA than with lateral disease in the men, but had a similar effect on both knee compartments in the women. After adjusting for the impact of squatting, the age-adjusted difference in prevalence of tibiofemoral OA was reduced from an excess of 14.4% to 9.5% in the Chinese women, but the difference in prevalence of tibiofemoral OA in the Chinese men increased after adjustment for age and squatting, from 2.9% lower to 7.0% lower as compared with their white counterparts.
CONCLUSION: Prolonged squatting is a strong risk factor for tibiofemoral knee OA among elderly Chinese subjects in Beijing, and accounts for a substantial proportion of the difference in prevalence of tibiofemoral OA between Chinese subjects in Beijing and white subjects in Framingham.

PMID 15077301
Hugues Louboutin, R Debarge, J Richou, Tarik Ait Si Selmi, Simon T Donell, Philippe Neyret, F Dubrana
Osteoarthritis in patients with anterior cruciate ligament rupture: a review of risk factors.
Knee. 2009 Aug;16(4):239-44. doi: 10.1016/j.knee.2008.11.004. Epub 2008 Dec 20.
Abstract/Text The risk factors for the development of osteoarthritis (OA) in patients who have had an anterior cruciate ligament (ACL) rupture are reviewed. Although the principle arthrogenic factor is the increased anterior tibial displacement that is associated with the rupture, other direct and indirect factors contribute. Meniscal and chondral injuries can be present before, during, and develop after the index injury, making assessment of the relative importance of each difficult. Most studies concentrate on the radiological changes following ACL rupture and reconstruction. However the rate of significant symptomatic OA needing major surgical intervention is lower. This needs to be considered when advising patients on the management of their ruptured ACL. The long-term outcome in patients who are symptomatically stable following an ACL rupture is uncertain, although in a small cohort of elite athletes all had degenerative changes by 35 years and eight out of 19 (42%) had undergone total knee replacement. At 20 years follow-up the reported risk of developing osteoarthritis is lower after ACL reconstruction (14%-26% with a normal medial meniscus, 37% with meniscectomy) to untreated ruptures (60%-100%).

PMID 19097796
T D Rosenberg, L E Paulos, R D Parker, D B Coward, S M Scott
The forty-five-degree posteroanterior flexion weight-bearing radiograph of the knee.
J Bone Joint Surg Am. 1988 Dec;70(10):1479-83.
Abstract/Text Posteroanterior weight-bearing radiographs, made with the knee in 45 degrees of flexion, were compared with conventional radiographs for fifty-five patients who had surgical treatment for a lesion causing pain in one knee. Narrowing of the cartilage space of two millimeters or more was defined as indicative of major degeneration (grade III or IV). Comparison of the intraoperatively observed degeneration with the narrowing that was seen on the radiographs revealed that the posteroanterior weight-bearing radiographs that were made with the knee in 45 degrees of flexion were more accurate (p less than 0.01), more specific (no false-positives) (p less than 0.01), and more sensitive (fewer false-negatives) than the conventional extension weight-bearing anteroposterior radiographs.

PMID 3198672
Mark D Kohn, Adam A Sassoon, Navin D Fernando
Classifications in Brief: Kellgren-Lawrence Classification of Osteoarthritis.
Clin Orthop Relat Res. 2016 Aug;474(8):1886-93. doi: 10.1007/s11999-016-4732-4. Epub 2016 Feb 12.
Abstract/Text
PMID 26872913
M T Nieminen, J Rieppo, J Töyräs, J M Hakumäki, J Silvennoinen, M M Hyttinen, H J Helminen, J S Jurvelin
T2 relaxation reveals spatial collagen architecture in articular cartilage: a comparative quantitative MRI and polarized light microscopic study.
Magn Reson Med. 2001 Sep;46(3):487-93. doi: 10.1002/mrm.1218.
Abstract/Text It has been suggested that orientational changes in the collagen network of articular cartilage account for the depthwise T2 anisotropy of MRI through the magic angle effect. To investigate the relationship between laminar T2 appearance and collagen organization (anisotropy), bovine osteochondral plugs (N = 9) were T2 mapped at 9.4T with cartilage surface normal to the static magnetic field. Collagen fibril arrangement of the same samples was studied with polarized light microscopy, a quantitative technique for probing collagen organization by analyzing its ability to rotate plane polarized light, i.e., birefringence (BF). Depthwise variation of safranin O-stained proteoglycans was monitored with digital densitometry. The spatially varying cartilage T2 followed the architectural arrangement of the collagen fibril network: a linear positive correlation between T2 and the reciprocal of BF was established in each sample, with r = 0.91 +/- 0.02 (mean +/- SEM, N = 9). The current results reveal the close connection between the laminar T2 structure and the collagen architecture in histologic zones.

Copyright 2001 Wiley-Liss, Inc.
PMID 11550240
Henning Madry, C Niek van Dijk, Magdalena Mueller-Gerbl
The basic science of the subchondral bone.
Knee Surg Sports Traumatol Arthrosc. 2010 Apr;18(4):419-33. doi: 10.1007/s00167-010-1054-z. Epub 2010 Jan 30.
Abstract/Text In the past decades, considerable efforts have been made to propose experimental and clinical treatments for articular cartilage defects. Yet, the problem of cartilage defects extending deep in the underlying subchondral bone has not received adequate attention. A profound understanding of the basic anatomic aspects of this particular site, together with the pathophysiology of diseases affecting the subchondral bone is the key to develop targeted and effective therapeutic strategies to treat osteochondral defects. The subchondral bone consists of the subchondral bone plate and the subarticular spongiosa. It is separated by the cement line from the calcified zone of the articular cartilage. A variable anatomy is characteristic for the subchondral region, reflected in differences in thickness, density, and composition of the subchondral bone plate, contour of the tidemark and cement line, and the number and types of channels penetrating into the calcified cartilage. This review aims at providing insights into the anatomy, morphology, and pathology of the subchondral bone. Individual diseases affecting the subchondral bone, such as traumatic osteochondral defects, osteochondritis dissecans, osteonecrosis, and osteoarthritis are also discussed. A better knowledge of the basic science of the subchondral region, together with additional investigations in animal models and patients may translate into improved therapies for articular cartilage defects that arise from or extend into the subchondral bone.

PMID 20119671
Michel D Crema, Frank W Roemer, David T Felson, Martin Englund, Ke Wang, Mohamed Jarraya, Michael C Nevitt, Monica D Marra, James C Torner, Cora E Lewis, Ali Guermazi
Factors associated with meniscal extrusion in knees with or at risk for osteoarthritis: the Multicenter Osteoarthritis study.
Radiology. 2012 Aug;264(2):494-503. doi: 10.1148/radiol.12110986. Epub 2012 May 31.
Abstract/Text PURPOSE: To assess the associations of meniscal tears, knee mal-alignment, cartilage damage, knee effusion, and body mass index with meniscal extrusion.
MATERIALS AND METHODS: The Multicenter Osteoarthritis study is an observational study of individuals who have or are at risk for knee osteoarthritis (OA). The HIPAA-compliant protocol was approved by the institutional review boards of all participating centers, and written informed consent was obtained from all patients. All subjects with available baseline knee radiographs and magnetic resonance (MR) images were included. MR imaging assessment of meniscal morphologic characteristics, meniscal position, and cartilage morphologic characteristics with use of the Whole-Organ Magnetic Resonance Imaging Score system was performed by two musculoskeletal radiologists. Cross-sectional associations of severity of meniscal tears, knee malalignment, tibiofemoral cartilage damage, knee effusion, and body mass index with meniscal extrusion were assessed by using logistic regression, with multiadjustments when testing each predictor.
RESULTS: A total of 1527 subjects (2131 knees; 2116 medial and 2106 lateral menisci) were included. Medially, meniscal tears, varus malalignment, and cartilage damage were associated with meniscal extrusion, with odds ratios (ORs) of 6.3 (95% confidence interval [CI]: 5.0, 8.0), 1.3 (95% CI: 1.1, 1.7), and 1.8 (95% CI: 1.4, 2.2), respectively. Laterally, meniscal tears, valgus malalignment, and cartilage damage were associated with meniscal extrusion, with ORs of 10.3 (95% CI: 7.1, 14.9), 2.2 (95% CI: 1.5, 3.2), and 2.0 (95% CI: 1.3, 2.9), respectively.
CONCLUSION: Meniscal tears are not the only factors associated with meniscal extrusion; other factors include knee malalignment and cartilage damage. Meniscal extrusion is probably an effect of the complex interactions among joint tissues and mechanical stresses involved in the OA process.

PMID 22653191
Paul Yf Lee, Thomas G Winfield, Shaun Rs Harris, Emerald Storey, Amit Chandratreya
Unloading knee brace is a cost-effective method to bridge and delay surgery in unicompartmental knee arthritis.
BMJ Open Sport Exerc Med. 2016;2(1):e000195. doi: 10.1136/bmjsem-2016-000195. Epub 2017 Feb 21.
Abstract/Text BACKGROUND: Unloading knee braces can provide good short-term pain relief for some patients with unicompartmental osteoarthritis (UOA). Their cost is relatively small compared with surgical interventions. However, no previous studies have reported their use over a duration of 5 years or more.
METHODS: Up to 8 years of prospective data were collected from 63 patients who presented with UOA. After conservative management with analgesia and physiotherapy, patients were offered an unloading brace. EQ-5D (EuroQol five dimensions) questionnaires were collected at baseline and after wearing the brace. Cost and quality-adjusted life years (QALYs) were compared with a total knee replacement (TKR) with an 8-month waiting duration and 8 years of results.
RESULTS: Patients experienced a mean increase in EQ-5D of 0.42 with an average duration of wear of 26.1 months resulting in an increase of 0.44 in QALYs with a mean cost of £625. The adoption of an unloader knee brace was found to be a short-term cost-effective treatment option with an 8-month incremental cost effectiveness ratio of £9599. Compared with no treatment, the unloader knee brace can be considered cost effective at 4 months or more. At 8 years follow-up, the unloader knee brace demonstrated QALYs gain of 0.43 and with an incremental cost-effectiveness ratio of -£6467 compared with TKR.
CONCLUSION: Unloading knee braces are cost effective for the management of UOA. These findings strongly support the undertaking of further research into the long-term impact of unloading knee brace. The unloader knee brace has benefits to the National Health Service for capacity, budget, waiting list duration, frequency of surgery and reducing the required severity of surgical intervention.

PMID 28879034
Rana S Hinman, Craig Payne, Ben R Metcalf, Tim V Wrigley, Kim L Bennell
Lateral wedges in knee osteoarthritis: what are their immediate clinical and biomechanical effects and can these predict a three-month clinical outcome?
Arthritis Rheum. 2008 Mar 15;59(3):408-15. doi: 10.1002/art.23326.
Abstract/Text OBJECTIVE: To assess immediate effects of laterally wedged insoles on walking pain, external knee adduction moment, and static alignment, and whether these immediate effects together with age, body mass index, and disease severity predict clinical outcome after 3 months of wearing insoles in medial knee osteoarthritis.
METHODS: Forty volunteers (mean age 64.7 years, 16 men) were tested in random order with and without a pair of 5 degrees full-length lateral wedges. Immediate changes in static alignment were measured via radiographic mechanical axis and changes in adduction moment via 3-dimensional gait analysis. After 3 months of treatment with insoles, changes in pain and physical functioning were assessed via the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and patient-perceived global change scores.
RESULTS: Reductions in the adduction moment occurred with insoles (first peak mean [95% confidence intervals (95% CI)] -0.22 [-0.28, -0.15] Nm/body weight x height %), accompanied by a reduction in walking pain of approximately 24% (mean [95% CI] -1.0 [-4.0, 2.0]). Insoles had no mean effect on static alignment. Mean improvement in WOMAC pain (P = 0.004) and physical functioning (mean [95% CI] -6 [-11, -1]) was observed at 3 months, with 25 (69%) and 26 (72%) of 36 individuals reporting global improvement in pain and functioning, respectively. Regression analyses demonstrated that disease severity, baseline functioning, and magnitude of immediate change in walking pain and the first peak adduction moment with insoles were predictive of clinical outcome at 3 months.
CONCLUSION: Lateral wedges immediately reduced knee adduction moment and walking pain but had no effect on static alignment. Although some parameters predicted clinical outcome, these explained only one-third of the variance, suggesting that other unknown factors are also important.

PMID 18311763
Kingkaew Pajareya, Navaporn Chadchavalpanichaya, Suteerat Timdang
Effectiveness of an elastic knee sleeve for patients with knee osteoarthritis: a randomized single-blinded controlled trial.
J Med Assoc Thai. 2003 Jun;86(6):535-42.
Abstract/Text OBJECTIVES: To study the effectiveness of elastic sleeves in patients with knee osteoarthritis (knee OA).
METHOD: Patients with knee OA attending the outpatient clinic of Siriraj Hospital, who met the eligibility criteria, were randomly allocated to receive an 8-week treatment protocol. The control group received acetaminophen, non-steroidal anti-inflammatory drugs (NSAIDs) and education. The study group received the same treatment, in combination with a daytime elastic knee sleeve. Primary outcome variable included change in aggregated functional performance time (AFPT).
RESULTS: In the immediate period after treatment, the study group had a mean improvement in AFPT of 1.63 seconds more than the control group (95% CI: 0.21-3.05, p = 0.025). At the end of the 8th week, the changes of AFPT were not statistically different between the two groups.
CONCLUSION: This study shows small short-term beneficial effects of an elastic sleeve in patients with knee OA in cases with acute exacerbation.

PMID 12924802
Yuji Uchio, Hiroyuki Enomoto, Mitsuhiro Ishida, Toshinaga Tsuji, Toshimitsu Ochiai, Shinichi Konno
Safety and efficacy of duloxetine in Japanese patients with chronic knee pain due to osteoarthritis: an open-label, long-term, Phase III extension study.
J Pain Res. 2018;11:1391-1403. doi: 10.2147/JPR.S171395. Epub 2018 Jul 31.
Abstract/Text PURPOSE: To assess long-term safety, tolerability, and efficacy of duloxetine in Japanese patients with chronic knee pain due to osteoarthritis.
METHODS: In this open-label extension study (NCT02335346), Japanese patients with knee osteoarthritis and pain (Brief Pain Inventory [BPI] - Severity average pain score ≥4 at start of randomized trial) who had previously received duloxetine 60 mg/day or placebo for 14 weeks in a double-blind randomized trial entered the extension and received duloxetine 60 mg/day for 48 weeks. The primary outcome was safety/tolerability, secondary outcomes were change in BPI-Severity (BPI-S) average pain, BPI-Interference (BPI-I), Patient Global Impression-Improvement (PGI-I), Clinical Global Impression-Improvement (CGI-I), 36-item Short-Form Health Survey (SF36), and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and exploratory outcomes were knee range of motion (efficacy outcome) and Kellgren-Lawrence grade (safety outcome).
RESULTS: Of 323 patients who completed the randomized trial, 93 (50 placebo, 43 duloxetine) entered the extension. Most patients (85, 91.4%) experienced an adverse event, most commonly constipation, nasopharyngitis, somnolence, and dry mouth (≥10% of patients). There were eight serious adverse events in seven patients and no deaths. No obvious duloxetine-related changes were observed in laboratory tests, vital signs, or electrocardiograms. The change from baseline in BPI-S average pain score was significant throughout the extension. Significant reductions in BPI-I, PGI-I, CGI-I, WOMAC, and SF36 scores were also maintained through 52 weeks. There were no substantial changes in range of motion or Kellgren-Lawrence grade.
CONCLUSION: In Japanese patients with chronic knee pain due to osteoarthritis, long-term treatment with duloxetine was well tolerated and associated with sustained improvements in pain and health-related quality of life without radiographic deterioration.

PMID 30104894
R D Altman, A Manjoo, A Fierlinger, F Niazi, M Nicholls
The mechanism of action for hyaluronic acid treatment in the osteoarthritic knee: a systematic review.
BMC Musculoskelet Disord. 2015 Oct 26;16:321. doi: 10.1186/s12891-015-0775-z. Epub 2015 Oct 26.
Abstract/Text BACKGROUND: Knee osteoarthritis (OA) is one of the leading causes of disability within the adult population. Current treatment options for OA of the knee include intra-articular (IA) hyaluronic acid (HA), a molecule found intrinsically within the knee joint that provides viscoelastic properties to the synovial fluid. A variety of mechanisms in which HA is thought to combat knee OA are reported in the current basic literature.
METHODS: We conducted a comprehensive literature search to identify currently available primary non-clinical basic science articles focussing on the mechanism of action of IA-HA treatment. Included articles were assessed and categorized based on the mechanism of action described within them. The key findings and conclusions from each included article were obtained and analyzed in aggregate with studies of the same categorical assignment.
RESULTS: Chondroprotection was the most frequent mechanism reported within the included articles, followed by proteoglycan and glycosaminoglycan synthesis, anti-inflammatory, mechanical, subchondral, and analgesic actions. HA-cluster of differentiation 44 (CD44) receptor binding was the most frequently reported biological cause of the mechanisms presented. High molecular weight HA was seen to be superior to lower molecular weight HA products. HA derived through a biological fermentation process is also described as having favorable safety outcomes over avian-derived HA products.
CONCLUSIONS: The non-clinical basic science literature provides evidence for numerous mechanisms in which HA acts on joint structures and function. These actions provide support for the purported clinical benefit of IA-HA in OA of the knee. Future research should not only focus on the pain relief provided by IA-HA treatment, but the disease modification properties that this treatment modality possesses as well.

PMID 26503103
Emmanuel Maheu, François Rannou, Jean-Yves Reginster
Efficacy and safety of hyaluronic acid in the management of osteoarthritis: Evidence from real-life setting trials and surveys.
Semin Arthritis Rheum. 2016 Feb;45(4 Suppl):S28-33. doi: 10.1016/j.semarthrit.2015.11.008. Epub 2015 Dec 2.
Abstract/Text The European Society for Clinical and Economic Aspects of Osteoporosis and Osteoarthritis (ESCEO) treatment algorithm recommends intra-articular (IA) hyaluronic acid (HA) for management of knee osteoarthritis (OA) as second-line treatment in patients who remain symptomatic despite use of non-steroidal anti-inflammatory drugs (NSAIDs). This recommendation is based upon accumulating evidence that IA HA provides a significant benefit in knee OA. There is good evidence that IA HA injections reduce pain and increase function in knee OA, and the benefits are long-lasting as compared with IA corticosteroids. Evidence from real-life studies of repeat courses of IA HA demonstrates an improvement in pain or function lasting up to 40 months (12 months after the last injection cycle), a reduction in use of concomitant analgesia by up to 50%, and suggests that there may be a delay in the need for total knee replacement (TKR) of around 2 years. The clinical benefit of IA HA on knee OA may be 2-fold: (i) mechanical viscosupplementation of the joint (allowing lubrication and shock absorption) and (ii) the re-establishment of joint homeostasis through induction of endogenous HA production, which continues long after the exogenous injection has left the joint. The magnitude of the clinical effect may be different for different HA products, but this has not been proven so far and requires further investigation. IA HA injections are generally considered to be safe, although a slightly higher number of cases of local reactions and post-injection non-septic arthritis has been reported with high molecular weight cross-linked HAs. The use of IA HA in knee OA patients with mild-moderate disease, and for more severe patients wishing to delay TKR surgery, is recommended by the ESCEO task force. Further investigation into the OA patient types most likely to benefit from IA HA is warranted. Viscosupplementation with IA HA is a safe and effective component of the multi-modal management of knee OA.

Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.
PMID 26806183
R R Bannuru, M C Osani, E E Vaysbrot, N K Arden, K Bennell, S M A Bierma-Zeinstra, V B Kraus, L S Lohmander, J H Abbott, M Bhandari, F J Blanco, R Espinosa, I K Haugen, J Lin, L A Mandl, E Moilanen, N Nakamura, L Snyder-Mackler, T Trojian, M Underwood, T E McAlindon
OARSI guidelines for the non-surgical management of knee, hip, and polyarticular osteoarthritis.
Osteoarthritis Cartilage. 2019 Nov;27(11):1578-1589. doi: 10.1016/j.joca.2019.06.011. Epub 2019 Jul 3.
Abstract/Text OBJECTIVE: To update and expand upon prior Osteoarthritis Research Society International (OARSI) guidelines by developing patient-focused treatment recommendations for individuals with Knee, Hip, and Polyarticular osteoarthritis (OA) that are derived from expert consensus and based on objective review of high-quality meta-analytic data.
METHODS: We sought evidence for 60 unique interventions. A systematic search of all relevant databases was conducted from inception through July 2018. After abstract and full-text screening by two independent reviewers, eligible studies were matched to PICO questions. Data were extracted and meta-analyses were conducted using RevMan software. Grading of Recommendations Assessment, Development, and Evaluation (GRADE) Evidence Profiles were compiled using the GRADEpro web application. Voting for Core Treatments took place first. Four subsequent voting sessions took place via anonymous online survey, during which Panel members were tasked with voting to produce recommendations for all joint locations and comorbidity classes. We designated non-Core treatments to Level 1A, 1B, 2, 3, 4A, 4B, or 5, based on the percentage of votes in favor, in addition to the strength of the recommendation.
RESULTS: Core Treatments for Knee OA included arthritis education and structured land-based exercise programs with or without dietary weight management. Core Treatments for Hip and Polyarticular OA included arthritis education and structured land-based exercise programs. Topical non-steroidal anti-inflammatory drugs (NSAIDs) were strongly recommended for individuals with Knee OA (Level 1A). For individuals with gastrointestinal comorbidities, COX-2 inhibitors were Level 1B and NSAIDs with proton pump inhibitors Level 2. For individuals with cardiovascular comorbidities or frailty, use of any oral NSAID was not recommended. Intra-articular (IA) corticosteroids, IA hyaluronic acid, and aquatic exercise were Level 1B/Level 2 treatments for Knee OA, dependent upon comorbidity status, but were not recommended for individuals with Hip or Polyarticular OA. The use of Acetaminophen/Paracetamol (APAP) was conditionally not recommended (Level 4A and 4B), and the use of oral and transdermal opioids was strongly not recommended (Level 5). A treatment algorithm was constructed in order to guide clinical decision-making for a variety of patient profiles, using recommended treatments as input for each decision node.
CONCLUSION: These guidelines offer comprehensive and patient-centered treatment profiles for individuals with Knee, Hip, and Polyarticular OA. The treatment algorithm will facilitate individualized treatment decisions regarding the management of OA.

Copyright © 2019 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.
PMID 31278997
Michael Blankstein, Brandon Lentine, Nathaniel J Nelms
Common Practices in Intra-Articular Corticosteroid Injection for the Treatment of Knee Osteoarthritis: A Survey of the American Association of Hip and Knee Surgeons Membership.
J Arthroplasty. 2021 Mar;36(3):845-850. doi: 10.1016/j.arth.2020.09.022. Epub 2020 Oct 8.
Abstract/Text BACKGROUND: Knee osteoarthritis nonoperative management options remain limited. Our aim is to define the current American Association of Hip and Knee Surgeons (AAHKS) members' practices and perceptions in terms of the frequency, formulation, use of concomitant aspiration, maximum lifetime number of injections, efficacy, interval between injection and surgery and complication rates.
METHODS: A 22-question survey based on Likert scale response anchors was approved and distributed by the AAHKS Research Committee to its membership by email during the Spring 2019 meeting. Data were managed with REDCap software.
RESULTS: Membership response totaled 537 of 2365 (22.7%) members. Highlights include every respondent using intra-articular corticosteroid injections (ICIs) in their practice, and most use a three-month minimum interval, although the preferred interval is longer. Near consensus was found waiting three months before surgery. There was a great variability in the number of injections allowed, and injections before surgery were very common. Nearly all responders use a local anesthetic mixture with the cortisone injection, but there was great variation in corticosteroid type: methylprednisolone (42%), triamcinolone (41%), betamethasone (13.3%), and dexamethasone (3.7%).
CONCLUSION: The results of our survey indicate the majority of the AAHKS members who completed the survey use ICIs routinely for treatment of knee osteoarthritis. There was near consensus in ICIs, which is effective with decreasing efficacy over serial injections, and an absolute minimum interval between injections was believed by most to be three months with no clearly defined lifetime limit and strong consensus for a three-month preoperative interval. The formulation of steroid, local anesthetic, and skin preparation technique varied greatly.

Copyright © 2020 Elsevier Inc. All rights reserved.
PMID 33616067
Naomasa Yokota, Mari Hattori, Tadahiko Ohtsuru, Masaki Otsuji, Stephen Lyman, Kazunori Shimomura, Norimasa Nakamura
Comparative Clinical Outcomes After Intra-articular Injection With Adipose-Derived Cultured Stem Cells or Noncultured Stromal Vascular Fraction for the Treatment of Knee Osteoarthritis.
Am J Sports Med. 2019 Sep;47(11):2577-2583. doi: 10.1177/0363546519864359. Epub 2019 Aug 2.
Abstract/Text BACKGROUND: Intra-articular injection of adipose-derived stem cells (ASCs) has shown promise for improving symptoms and cartilage quality in the treatment of osteoarthritis (OA). However, while most preclinical studies have been performed with plastic-adherent ASCs, most clinical trials are being conducted with the stromal vascular fraction (SVF), prepared from adipose tissue without prior culture.
PURPOSE: To directly compare clinical outcomes of intra-articular injection with ASCs or SVF in patients with knee OA.
STUDY DESIGN: Cohort study; Level of evidence, 3.
METHODS: The authors retrospectively compared 6-month outcomes in 42 patients (59 knees) receiving intra-articular injection with 12.75 million ASCs and 38 patients (69 knees) receiving a 5-mL preparation of SVF. All patients had Kellgren-Lawrence grade 2, 3, or 4 knee OA and had failed standard medical therapy. The visual analog scale (VAS) pain score and Knee injury and Osteoarthritis Outcome Score (KOOS) at baseline and 1, 3, and 6 months after injection were considered as outcomes. Outcome Measures in Rheumatology-Osteoarthritis Research Society International (OMERACT-OARSI) criteria were also used to assess positive response. A repeated measures analysis of variance was used for comparison between the treatment groups.
RESULTS: No major complications occurred in either group. The SVF group had a higher frequency of knee effusion (SVF 8%, ASC 2%) and minor complications related to the fat harvest site (SVF 34%, ASC 5%). Both groups reported improvements in pain VAS and KOOS domains. Specifically, in the ASC group, symptoms improved earlier (by 3 months; P < .05) and pain VAS decreased to a greater degree (55%; P < .05) compared with the SVF group (44%). The proportion of OMERACT-OARSI responders in the ASC group was slightly higher (ASCs, 61%; SVF, 55%; P = .25).
CONCLUSION: It was observed that both ASCs and SVF resulted in clinical improvement in patients with knee OA, but that ASCs outperform SVF in the early reduction of symptoms and pain with less comorbidity.

PMID 31373830
Alexandra Kirkley, Trevor B Birmingham, Robert B Litchfield, J Robert Giffin, Kevin R Willits, Cindy J Wong, Brian G Feagan, Allan Donner, Sharon H Griffin, Linda M D'Ascanio, Janet E Pope, Peter J Fowler
A randomized trial of arthroscopic surgery for osteoarthritis of the knee.
N Engl J Med. 2008 Sep 11;359(11):1097-107. doi: 10.1056/NEJMoa0708333.
Abstract/Text BACKGROUND: The efficacy of arthroscopic surgery for the treatment of osteoarthritis of the knee is unknown.
METHODS: We conducted a single-center, randomized, controlled trial of arthroscopic surgery in patients with moderate-to-severe osteoarthritis of the knee. Patients were randomly assigned to surgical lavage and arthroscopic débridement together with optimized physical and medical therapy or to treatment with physical and medical therapy alone. The primary outcome was the total Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score (range, 0 to 2400; higher scores indicate more severe symptoms) at 2 years of follow-up. Secondary outcomes included the Short Form-36 (SF-36) Physical Component Summary score (range, 0 to 100; higher scores indicate better quality of life).
RESULTS: Of the 92 patients assigned to surgery, 6 did not undergo surgery. Of the 86 patients assigned to control treatment, all received only physical and medical therapy. After 2 years, the mean (+/-SD) WOMAC score for the surgery group was 874+/-624, as compared with 897+/-583 for the control group (absolute difference [surgery-group score minus control-group score], -23+/-605; 95% confidence interval [CI], -208 to 161; P=0.22 after adjustment for baseline score and grade of severity). The SF-36 Physical Component Summary scores were 37.0+/-11.4 and 37.2+/-10.6, respectively (absolute difference, -0.2+/-11.1; 95% CI, -3.6 to 3.2; P=0.93). Analyses of WOMAC scores at interim visits and other secondary outcomes also failed to show superiority of surgery.
CONCLUSIONS: Arthroscopic surgery for osteoarthritis of the knee provides no additional benefit to optimized physical and medical therapy. (ClinicalTrials.gov number, NCT00158431.)

2008 Massachusetts Medical Society
PMID 18784099
L L Johnson
Arthroscopic abrasion arthroplasty: a review.
Clin Orthop Relat Res. 2001 Oct;(391 Suppl):S306-17.
Abstract/Text Arthroscopic abrasion arthroplasty is an elaborate description for an extensive multiple tissue debridement for patients seeking an alternative to total knee replacement. The operation is palliative, not curative. In patients seeking an alternative to total knee replacement, the definitive operation may be avoided or deferred in a high percentage of patients as many as 5 years. Because the abrasion portion of the operation is accompanied by multiple tissue type debridement, it is not known what clinical benefit the abrasion aspect contributes. Furthermore, no prospective randomized clinical studies have been done and most clinicians reporting on their experience with the procedure have varied the indications, technique, and/or postoperative treatment. Future investigation may answer these clinical questions. It is known that fibrocartilage forms at the abrasion site. The reparative tissue has many of the characteristics of cartilage, but does not have the biomechanical properties of articular cartilage. The fibrocartilage has shown durability for many years confirmed during opportunistic second look arthroscopy. The applications of growth factor science or genetic engineering may provide means of converting the regenerative tissue of abrasion arthroplasty to mature articular cartilage.

PMID 11603714
Abstract/Text A retrospective review with a mean follow-up time of 60 months was performed on 126 patients who had treatment of unicompartmental gonarthrosis with either abrasion arthroplasty plus arthroscopic debridement or arthroscopic debridement alone. Fifty-nine patients had abrasion arthroplasty and arthroscopic debridement, and 67 patients had arthroscopic debridement alone. All patient had stage II Ahlbäck changes roentgenographically, as well as Outerbridge stage IV changes arthroscopically in the involved compartment. All the knees were evaluated postoperatively at a minimum of 60 months, utilizing The Hospital For Special Surgery Knee Scoring System. In the group treated with abrasion arthroplasty, 51% had good to excellent results, 16% had fair results, and 33% had poor results. The conditions of ten of the patients who had poor results actually became worse subsequent to their abrasion arthroplasty. In the group that had arthroscopic debridement, 66% had good to excellent results, 13% had fair results, and 21% had poor results. The conditions of 12 of the patients who had poor results actually became worse subsequent to the arthroscopic debridement.

PMID 2706048
Adolph V Lombardi, Keith R Berend, Joseph R Leith, Gerardo P Mangino, Joanne B Adams
Posterior-stabilized constrained total knee arthroplasty for complex primary cases.
J Bone Joint Surg Am. 2007 Oct;89 Suppl 3:90-102. doi: 10.2106/JBJS.G.00586.
Abstract/Text
PMID 17908875
Gun-Woo Kim, Quan He Jin, Jun-Hyuk Lim, Eun-Kyoo Song, Jong-Keun Seon
No difference of survival between cruciate retaining and substitution designs in high flexion total knee arthroplasty.
Sci Rep. 2021 Mar 22;11(1):6537. doi: 10.1038/s41598-021-85892-1. Epub 2021 Mar 22.
Abstract/Text The aim of this study was to compare the long-term implant survival and outcomes in patients with high-flexion cruciate-retaining (CR) or high-flexion posterior cruciate-substituting (PS) knee implants. A total of 253 knees (CR group: 159 vs. PS group: 94) were available for examination over a mean follow-up of 10 years. Clinical outcomes were assessed including the Hospital for Special Surgery score, Knee Society score and Western Ontario and McMaster Universities Osteoarthritis Index score at the final follow-up. Radiologic measurements were also assessed including the hip-knee-ankle angle and radiolucent lines according to the KSS system at the final follow-up. The survival rate was analyzed using the Kaplan-Meier method. At the final follow-up, the mean total HSS scores were similar between the two groups (p = 0.970). The mean hip-knee-ankle angle at the final follow-up was similar between groups (p = 0.601). The 10- and 15-year survival rates were 95.4% and 93.3% in the CR group and 92.7% and 90.9% in the PS group, respectively, with no significant difference. Similar clinical and radiographic outcomes could be achieved with both the high-flexion CR and high-flexion PS total knee designs without a difference in survival rate after a 10-year follow-up.

PMID 33753767
Young-Hoo Kim, Jang-Won Park
Comparison of Modular Conventional and High-Flexion Posterior-Stabilized Total Knee Arthroplasties in the Same Patients at a Mean Follow-Up of 15 Years.
J Arthroplasty. 2020 May;35(5):1262-1267. doi: 10.1016/j.arth.2019.12.022. Epub 2019 Dec 17.
Abstract/Text BACKGROUND: As previous studies are limited to short-term clinical data on conventional and high-flexion total knee arthroplasties (TKAs), long-term clinical data on these TKAs remain unclear. Therefore, we evaluated long-term functional outcome, range of knee motion, revision rate, implant survival, and the prevalence of osteolysis after conventional and high-flexion TKAs in the same patients.
METHODS: The authors evaluated a cohort of 1206 patients with a mean age of 65.3 ± 7 years (range: 22-70) who underwent bilateral simultaneous sequential TKAs. One knee received a conventional TKA and the other received a high-flexion TKA. The mean duration of follow-up was 15.6 years (range: 14-17).
RESULTS: No significant differences were found between the 2 groups at the latest follow-up with respect to Knee Society score (93 vs 92 points, P = .765), pain score (45 vs 44 points, P = .641), range of knee motion (125° vs 126°, P = .712), and radiographic and computed tomography scan results. Furthermore, no significant revision rate differences were found between the 2 groups (1.3% for conventional TKA vs 1.6% for high-flexion TKA; P = .137). There was no osteolysis recorded in either group. The rate of survivorship free of implant revision or aseptic loosening was 98.7% (95% CI = 91-100) for conventional TKA and 98.4% (95% CI = 91-100) for high-flexion TKA at 17 years.
CONCLUSION: At the latest follow-up, we were not able to demonstrate any significant difference between conventional and high-flexion TKAs with respect to functional outcome scores, range of knee motion, revision rate, implant survival, and prevalence of osteolysis.

Copyright © 2019 Elsevier Inc. All rights reserved.
PMID 31902619
Won-Gyun Lee, Eun-Kyoo Song, Seung-Won Choi, Quan He Jin, Jong-Keun Seon
Comparison of Posterior Cruciate-Retaining and High-Flexion Cruciate-Retaining Total Knee Arthroplasty Design.
J Arthroplasty. 2020 Mar;35(3):752-755. doi: 10.1016/j.arth.2019.10.008. Epub 2019 Oct 10.
Abstract/Text BACKGROUND: High-flexion prostheses have been developed to achieve deep flexion after total knee arthroplasty. The purpose of this study is to compare standard NexGen (CR, cruciate-retaining) and high-flexion NexGen (CR-flex) total knee prostheses in terms of range of motion, clinical and radiologic outcomes, rates of complications, and survivorship in long-term follow-up.
METHODS: From January 2000 to December 2008, 423 consecutive knees underwent total knee arthroplasty using standard CR or CR-flex prostheses. Fifty-three patients were lost to follow-up or declined to participate and 54 died, leaving 290 knees. The minimum duration of follow-up was 8 years (mean 10.1 years). Physical examination and knee scoring of patients were assessed preoperatively, at 6 months and 1 year after surgery, and annually thereafter. Supine anteroposterior and lateral radiographs and standing anteroposterior hip-to-ankle radiographs were obtained preoperatively and at each follow-up.
RESULTS: Mean postoperative range of motions in the standard CR group and the CR-flex group were similar, showing no significant difference between the 2 groups (P = .853). At the time of the final follow-up, mean total Hospital for Special Surgery scores were similar between the 2 groups (P = .118). Mean Knee Society pain (P = .325) and function scores (P = .659) were also comparable between the 2 groups. Western Ontario and McMaster Universities Osteoarthritis Index score showed no intergroup difference either (P = .586). The mean hip-knee-ankle angle at the final follow-up was approximately the same (P = .940). Mean coronal angles of femoral and tibial component at final follow-up were also similar (P = .211 and P = .764, respectively). The prevalence of the radiolucent line was 0.6% in the standard CR group and 0.9% in the CR-flex group. Estimated survival rate according to Kaplan-Meier survival analysis was 97.2% in the standard CR group and 95.6% in the CR-flex group at mean follow-up of 10.1 years.
CONCLUSION: This study suggests that excellent clinical and radiographic outcomes could be achieved with both standard and high-flexion CR total knee designs. High-flexion CR prosthesis did not show any advantages over the standard design.

Copyright © 2019 Elsevier Inc. All rights reserved.
PMID 31676176
Steven Yacovelli, Luis C Grau, William J Hozack, P Maxwell Courtney
Functional Outcomes are Comparable Between Posterior Stabilized and Cruciate-Substituting Total Knee Arthroplasty Designs at Short-Term Follow-up.
J Arthroplasty. 2021 Mar;36(3):986-990. doi: 10.1016/j.arth.2020.09.008. Epub 2020 Sep 12.
Abstract/Text BACKGROUND: Posterior stabilized (PS) polyethylene inserts have been shown to have excellent long-term functional results following total knee arthroplasty (TKA). A cruciate-substituting (CS) design has been introduced to minimize bony resection and eliminate concerns regarding wear on the PS post. The purpose of this study is to compare the outcomes of patients who underwent TKA using either a PS or CS insert.
METHODS: We reviewed a consecutive series of 5970 patients who underwent a cruciate-sacrificing TKA and received either a PS (3,314) or CS (2,656) polyethylene liner. We compared demographics, Knee Injury and Osteoarthritis Outcome Score Jr (KOOS Jr), Short-Form 12 (SF-12) scores, and revision rates between the groups at a minimum 2 years followup. A multivariate regression was performed to identify the independent effect of design on functional outcomes.
RESULTS: Revision rates between the groups were comparably low (0.35% for PS vs 0.51% for CS, P = .466) at an overall mean follow-up of 43 months. Patients in the PS cohort had statistically higher KOOS Jr scores at 2 years (69.8 vs 72.9, P < .001). Multivariate regression analysis found CS patients to have lower postoperative KOOS Jr scores (estimate -2.26, P = .003), and less overall improvement in KOOS Jr scores (estimate -2.42, P = .024) than PS patients, but neither was a clinically significant difference.
CONCLUSION: Patients who undergo TKA with a CS polyethylene insert have comparable functional outcomes and revision rates to those with a PS design at short-term follow-up. Longer follow-up is needed to determine whether CS can match the outstanding track record of PS TKA.

Copyright © 2020 Elsevier Inc. All rights reserved.
PMID 32994108
Robert B Bourne, Bert M Chesworth, Aileen M Davis, Nizar N Mahomed, Kory D J Charron
Patient satisfaction after total knee arthroplasty: who is satisfied and who is not?
Clin Orthop Relat Res. 2010 Jan;468(1):57-63. doi: 10.1007/s11999-009-1119-9.
Abstract/Text UNLABELLED: Despite substantial advances in primary TKA, numerous studies using historic TKA implants suggest only 82% to 89% of primary TKA patients are satisfied. We reexamined this issue to determine if contemporary TKA implants might be associated with improved patient satisfaction. We performed a cross-sectional study of patient satisfaction after 1703 primary TKAs performed in the province of Ontario. Our data confirmed that approximately one in five (19%) primary TKA patients were not satisfied with the outcome. Satisfaction with pain relief varied from 72-86% and with function from 70-84% for specific activities of daily living. The strongest predictors of patient dissatisfaction after primary TKA were expectations not met (10.7x greater risk), a low 1-year WOMAC (2.5x greater risk), preoperative pain at rest (2.4x greater risk) and a postoperative complication requiring hospital readmission (1.9x greater risk).
LEVEL OF EVIDENCE: Level II, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.

PMID 19844772
Hasan R Mohammad, Louise Strickland, Thomas W Hamilton, David W Murray
Long-term outcomes of over 8,000 medial Oxford Phase 3 Unicompartmental Knees-a systematic review.
Acta Orthop. 2018 Feb;89(1):101-107. doi: 10.1080/17453674.2017.1367577. Epub 2017 Aug 23.
Abstract/Text Background and purpose - There is debate as to the relative merits of unicompartmental and total knee arthroplasty (UKA, TKA). Although the designer surgeons have achieved good results with the Oxford UKA there is concern over the reproducibility of these outcomes. Therefore, we evaluated published long-term outcomes of the Oxford Phase 3 UKA. Patients and methods - We searched databases to identify studies reporting ≥10 year outcomes of the medial Oxford Phase 3 UKA. Revision, non-revision, and re-operation rates were calculated per 100 component years (% pa). Results - 15 studies with 8,658 knees were included. The annual revision rate was 0.74% pa (95% CI 0.67-0.81, n = 8,406) corresponding to a 10-year survival of 93% and 15-year survival of 89%. The non-revision re-operation rate was 0.19% pa (95% CI 0.13-0.25, n = 3,482). The re-operation rate was 0.89% pa (95% CI 0.77-1.02, n = 3,482). The most common causes of revision were lateral disease progression (1.42%), aseptic loosening (1.25%), bearing dislocation (0.58%), and pain (0.57%) (n = 8,658). Average OKS scores were 40 at 10 years (n = 3,417). The incidence of medical complications was 0.83% (n = 1,443). Interpretation - Very good outcomes were achieved by both designer and non-designer surgeons. The PROMs, medical complication rate, and non-revision re-operation rate were better than those found in meta-analyses and publications for TKA but the revision rate was higher. However, if failure is considered to be all re-operations and not just revisions, then the failure rate of UKA was less than that of TKA.

PMID 28831821
Maxime Fabre-Aubrespy, Matthieu Ollivier, Sébastien Pesenti, Sébastien Parratte, Jean-Noël Argenson
Unicompartmental Knee Arthroplasty in Patients Older Than 75 Results in Better Clinical Outcomes and Similar Survivorship Compared to Total Knee Arthroplasty. A Matched Controlled Study.
J Arthroplasty. 2016 Dec;31(12):2668-2671. doi: 10.1016/j.arth.2016.06.034. Epub 2016 Jun 29.
Abstract/Text BACKGROUND: Due to the potential reduction of morbidity and mortality, unicompartmental knee arthroplasty (UKA) may represent an interesting solution for older patients with unicompartmental arthritis. It was our hypothesis that UKA can represent an alternative to total knee arthroplasty (TKA) for patients older than 75. We, thus, aimed to compare in those patients (1) functional results, (2) rates of forgotten joint, and (3) survivorships of UKA vs TKA.
METHODS: In this retrospective matched-pair study, 101 patients who underwent UKA in our institution were included and then matched one-to-one with TKA group based on age, gender, body mass index, preoperative Knee Society Score (KSS). Inclusion criteria were age between 75 and 90 years on the day of surgery, knee arthroplasty performed for primary osteoarthritis or osteonecrosis of the knee. All patients were evaluated clinically (using KSS, Knee Injury Osteoarthritis Outcome Score [KOOS], and Forgotten Joint Score) at 1, 2, and every 5 years, thereafter. Survivorships of UKA and TKA implants were also compared.
RESULTS: At last follow-up, patients from UKA group had better KSS than in TKA group, (respectively, KSS function 82.8 ± 12.2 vs 79.2 ± 13.1 [P = .0448] and KSS knee 88.2 ± 8.9 vs 82.3 ± 12.5 [P = .0005]). Knee Injury Osteoarthritis Outcome Scores were also higher in UKA group (all P < .001) as well as the rate of forgotten knees (42% vs 25% P = .01). Sixteen-year survivorships free from revision for any reason were similar in the 2 groups (91.8% vs 94.6% P = .66).
CONCLUSION: The results of our study showed that UKA provide higher function and better forgotten joint scores with similar survivorship, compared to TKA, for patients older than 75.

Copyright © 2016 Elsevier Inc. All rights reserved.
PMID 27480824

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