Single-Leg Squat Performance is Impaired 1 to 2 Years After Hip Arthroscopy

PM R. 2016 Apr;8(4):321-330. doi: 10.1016/j.pmrj.2015.07.004. Epub 2015 Jul 27.


Objective: To evaluate single-leg squat performance 1-2 years after arthroscopy for intra-articular hip pathology compared with control subjects and the nonsurgical limb, and to investigate whether single-leg squat performance on the operated limb was associated with hip muscle strength.

Design: Cross-sectional study.

Setting: Private physiotherapy clinic and university laboratory.

Participants: Thirty-four participants (17 women, 36.7 ± 12.6 years) 1-2 years after hip arthroscopy and 34 gender-matched control subjects (17 women, 33.1 ± 11.9 years).

Methods: Participants performed single-leg squats using a standardized testing procedure. Squat performance was captured using video. Video footage was uploaded and reformatted for analyses. Hip muscle strength was measured with handheld dynamometry using reliable methods.

Outcome measures: Frontal plane pelvic obliquity, hip adduction, and knee valgus were measured. Repeated measures analysis of variance evaluated between-group differences, with limb as a within-subjects factor (surgical versus nonsurgical) and gender as a between-subjects factor (P < .05).

Results: The hip arthroscopy group demonstrated significantly greater apparent hip adduction (mean difference 2.7°, 95% confidence interval [CI] 0.7°-4.8°) and apparent knee valgus (4.0°, 95% CI 1.0°-7.1°) at peak squat depth compared with control subjects. The operated limb also demonstrated significantly greater pelvic obliquity during single-leg stance compared with the nonsurgical limb (1.2°, 95% CI 0.1°-2.3°). Women had significantly greater apparent hip adduction (standing 1.6°, 95% CI 0.5°-2.6°; peak squat depth 2.4°, 95% CI 0.3°-4.4°) and apparent knee valgus (standing 3.3°, 95% CI 1.8°-4.7°; peak squat depth 3.1°, 95% CI 0°-6.1°). Significant positive correlations were found between frontal plane angles and hip flexor and extensor peak torque (P > .05).

Conclusion: One to 2 years after hip arthroscopy, deficits in single-leg squat performance exist that have the potential to increase hip joint impingement and perpetuate postoperative symptoms. Rehabilitation after hip arthroscopy should target retraining in functional single-leg positions.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Arthroscopy / methods*
  • Biomechanical Phenomena
  • Cross-Sectional Studies
  • Electromyography
  • Female
  • Hip Joint / diagnostic imaging
  • Hip Joint / physiopathology*
  • Humans
  • Joint Diseases / diagnosis*
  • Joint Diseases / physiopathology
  • Leg / physiopathology*
  • Muscle Strength / physiology
  • Muscle, Skeletal / diagnostic imaging
  • Muscle, Skeletal / physiopathology*
  • Posture / physiology*
  • Range of Motion, Articular / physiology*