Ober testでは腸脛靭帯のtightnessを評価できない？

Ober testといえば理学療法士・作業療法士が大腿筋膜張筋や腸脛靭帯の短縮を評価する際に用いる整形外科テストの1つです．

昔からなじみ深いこのOber testですが腸脛靭帯のtightnessを評価できない可能性を示唆する論文が報告されております．

今回はOber testでは腸脛靭帯のtightnessを評価できないかもしれないといった話です．

今回ご紹介する論文

Am J Sports Med. 2016 Mar;44(3):696-701. doi: 10.1177/0363546515621762. Epub 2016 Jan 11.

An Anatomic Investigation of the Ober Test

Gilbert M Willett 1, Sarah A Keim 2, Valerie K Shostrom 3, Carol S Lomneth 2

Affiliations expand

PMID: 26755689 DOI: 10.1177/0363546515621762

今回ご紹介する論文は2016年に掲載された比較的新しい論文です

研究の背景

Background: Recent studies have questioned the importance of the iliotibial band (ITB) in lateral knee pain. The Ober test or modified Ober test is the most commonly recommended physical examination tool for assessment of ITB tightness. No studies support the validity of either Ober test for measuring ITB tightness.

近年の研究では膝関節外側の疼痛における腸脛靭帯の重要性に関してぎもんしされております．

腸脛靭帯のtightnessを評価するために最も一般的に推奨されている検査としてOber testや修正Ober testが挙げられます．

しかしながら腸脛靭帯のtightnessの評価にOber testが有効か否かを明らかにした研究というのは少ないのが実際です．

研究の目的

Purpose/hypothesis: The purpose of this study was to assess the effects of progressive transection of the ITB, gluteus medius and minimus (med/min) muscles, and hip joint capsule of lightly embalmed cadavers on Ober test results and to compare them with assessment of all structures intact. In addition, thigh position change between gluteus med/min transection and hip capsule transection was also assessed for both versions of the Ober test. It was hypothesized that transection of the ITB would significantly increase thigh adduction range of motion as measured by an inclinometer when performing either Ober test and that subsequent structure transections (gluteus med/min muscles followed by the hip joint capsule) would cause additional increases in thigh adduction.

この研究では検体を用いて，腸脛靭帯，大殿筋，小殿筋，股関節関節包の切除がOber testの結果に及ぼす影響を評価することを目的としております．

またOber testと修正Ober testの2パターンのテストについて，大殿筋，小殿筋，股関節関節包切除時の大腿部の傾斜角度（股関節内転可動域）の変化も評価ししております．

Ober testまたは修正Ober testを行った場合には，腸脛靭帯の切除によって傾斜計で測定した股関節内転可動域が有意に増加し，その後の大殿筋・小殿筋・股関節関節包の切除によって股関節内転可動域がさらに増加するという仮説を立てた上で研究が行われております．

研究デザイン

Study design: Controlled laboratory study.

研究デザインはコントロールされた実験研究となっております．

研究の方法

Methods: The lower limbs of lightly embalmed cadavers were assessed for midthigh ITB transection versus intact by use of the Ober (n = 28) and modified Ober (n = 34) tests; 18 lower limbs were assessed for all conditions (intact band, followed by sequential transections of the ITB midthigh, gluteus med/min muscles, hip joint capsule) by use of both Ober tests. Paired t tests were used to compare changes in Ober test results between conditions.

Ober test（n = 28）ならびに修正Ober test（n = 34）を用いて，腸脛靭帯を部分的に切除した状態と切除していない状態で比較しております．

また18肢をOber testおよび修正Ober testを用いて，すべての条件（腸脛靭帯脾切除，腸脛靭帯部分切除，大殿筋切除，股関節関節包切除）で評価しております．

最終的に対応のあるt検定を用いて比較を行っております．

研究の結果

Results: No significant changes in thigh position (adduction) occurred in either version of the Ober test after ITB transection. Significant differences were noted for intact band versus gluteus med/min transection and intact band versus hip joint capsule transection (P < .0001) for all findings for both tests. Mean inclinometer measurements for the modified Ober were 4.28° (n = 34 for intact vs ITB transection comparisons), 3.33° (n = 18 for subsequent intact vs gluteus muscle and hip capsule transection comparisons), 5.00° (n = 34 for midthigh ITB transection), 11.20° (gluteus med/min transection), and 13.20° (hip capsule transection). For the Ober test, measures were -2.90° (n = 28 for intact vs ITB transection comparisons), -2.20° (n = 18 for subsequent intact vs gluteus muscle and hip capsule transection comparisons), -2.20° (n = 34 for midthigh ITB transection), 6.50° (gluteus med/min transection), and 9.53° (hip capsule transection). Statistically significant differences were also noted between test findings comparing gluteus med/min transection to hip capsule transection (Ober, P < .0001; modified Ober, P = .0036).

腸脛靭帯切除後にはOber test，修正Ober testいずれにおいても股関節内転可動域に有意な変化は認めませんでした．

一方でOber test，修正Ober testいずれにおいても大殿筋・小殿筋・股関節関節包の切除後に内転可動域に有意な変化が生じております．

股関節内転可動域の測定値は上述の通りです．

研究の結論

Conclusion: The study findings refute the hypothesis that the ITB plays a role in limiting hip adduction during either version of the Ober test and question the validity of these tests for determining ITB tightness. The findings underscore the influence of the gluteus medius and minimus muscles as well as the hip joint capsule on Ober test findings.

この研究の結果から，Ober testまたは修正Ober testは腸脛靱帯が股関節内転運動を制限する役割を果たしているという仮説を否定し，腸脛靭帯のtightnessを評価するテストとしての妥当性に疑問が残る結果でありました．

また大殿筋・小殿筋・股関節関節包のtightnessがOber testに影響を与えることが示唆されました．

臨床的関連性

Clinical relevance: The results of this study suggest that the Ober test assesses tightness of structures proximal to the hip joint, such as the gluteus medius and minimus muscles and the hip joint capsule, rather than the ITB.

この研究結果からOber testは腸脛靭帯ではなく，大殿筋・小殿筋・股関節関節包等の股関節近位の軟部組織のtightnessの評価として適切である可能性が示唆されます．