Proximal Overresection During Femoral Osteochondroplasty Negatively Affects the Distractive Stability of the Hip Joint: A Cadaver Study

The Contribution of Soft Tissue and Bony Stabilizers to the Hip Suction Seal: A Systematic Review of Biomechanical Studies

BACKGROUND

Previous biomechanical studies have identified capsular closure, labral repair or reconstruction, and osteochondroplasty as important surgical interventions to improve hip stability.

PURPOSE

To investigate the outcome metrics used to quantify hip stability and assess and measure the relative contributions of the labrum, capsule, and bone to hip stability through a quantitative analysis.

STUDY DESIGN

Systematic review and meta-analysis; Level of evidence, 4.

METHODS

PubMed and Embase databases were searched using the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Included studies evaluated cadaveric hip biomechanics related to capsular, labral, and bony management during hip arthroscopy. Studies were assessed for distraction force and distance, fluid measures, and contact forces used to quantify the suction seal. Exclusion criteria included open surgery, arthroplasty, reorientation osteotomy, or traumatic dislocation.

RESULTS

A total of 33 biomechanical studies comprising 322 hips that evaluated 1 or more of the following were included: distraction force or distance (24 studies), fluid measures (10 studies), and contact forces (6 studies). Compared with a capsulotomy or capsulectomy, capsular repair or reconstruction demonstrated greater resistance to distraction (standardized mean difference [SMD], 1.13; 95% CI, 0.46-1.80; P = .0009). Compared with a labral tear, a labral repair or reconstruction demonstrated less resistance to distraction (SMD, -0.67; 95% CI, -1.25 to -0.09; P = .02). Compared with a labral debridement, repair or reconstruction demonstrated greater resistance to distraction (SMD, 1.74; 95% CI, 1.23 to 2.26; P < .00001). No quantitative analysis was feasible from studies evaluating the effect of osseous resection due to the heterogeneity in methodology and outcome metrics assessed.

CONCLUSION

Most biomechanical evidence supports capsulotomy repair or reconstruction to improve hip distractive stability at the end of hip arthroscopic surgery. While the repair of a torn labrum does not improve distractive resistance, it is superior to labral debridement in most biomechanical studies.

Image Observation Study on Improving the Effectiveness of Muscle Strength Training for Sprinters

In order to solve the problem of improving the effectiveness of muscle strength training for sprinters, this paper presents a study using image observation technology. The main content of this technology research is to determine the experimental object and method according to the image observation and muscle characteristics. Through the data processing and other processes, it is concluded that the image observation technology has a high accuracy in the observation of muscle movement patterns. The experimental results show that when the relationship number r = 0.99, the average error of prediction is 0.09, and the image observation technology has a high accuracy in the observation of muscle movement. Conclusion. It is proved that the technical research of image observation is effective and accurate for improving the training of sports muscle strength of sprinters.

Editorial Commentary: Postoperative Alpha Angle and Return to Sport: One Piece of the Puzzle

Return-to-sport rates following arthroscopic treatment of femoroacetabular impingement are high; however, the predictors of failure to return to sport must be elucidated. Recent data suggest that the postoperative alpha angle may be a significant predictor of return to sport in athletes, despite the fact that the role of radiographic measurements on postoperative outcomes is debated in the literature. Nonetheless, it is incumbent on surgeons to fully understand the unique biomechanics of the hip in each sport and consider each patient's unique anatomy when undertaking cam resection. Recreation of the motion at-risk during a careful intraoperative dynamic examination is imperative to ensure that all areas of impingement have been eradicated while attentively avoiding over-resection. While the postoperative alpha angle is an important metric for surgeons to keep in mind, it may only represent one piece of the puzzle.

Postoperative Alpha Angle Is Predictive of Return to Sport in Athletes Undergoing Hip Arthroscopy for Femoroacetabular Impingement

PURPOSE

To identify clinical and radiographic factors that predict return to sport in athletes undergoing hip arthroscopy and to determine thresholds for significant predictors.

METHODS

Data were reviewed on all patients who underwent primary hip arthroscopy between November 2008 and August 2018. Patients were included if they played professional, college, or high school sports within 1 year before surgery and had preoperative, 3-month, 1-year, and 2-year postoperative patient-reported outcome scores for modified Harris Hip Score, Hip Outcome Score-Sport Specific-Subscale, and Nonarthritic Hip Score. Rates of achieving the minimal clinically important difference also were evaluated. Patients were divided into groups based on whether they returned to sport at the same or greater level. Multivariate logistic regression and receiver operator characteristic analysis were used to evaluate the correlation between significant variables and return to sport.

RESULTS

A total of 136 patients with a mean age of 20.8 ± 7.07 years were included. Among athletes who attempted to return, professional and collegiate athletes returned to sport at any level at a rate of 85.0% (51/60), and high-school athletes returned at a rate of 88.1% (52/59). Competition level, postoperative alpha angle, change in alpha angle, and postoperative patient-reported outcomes were significantly different between groups. Athletes who returned to sport achieved the minimal clinically important difference for Hip Outcome Score-Sport Specific-Subscale at significantly higher rates than athletes who did not return to sport (91.6% vs 71.7%, P = .002, S = 8.97). The multivariate logistic regression model identified postoperative alpha angle as a statistically significant predictor of return to sport (P < .001, S > 9.97 [odds ratio 0.85, 95% confidence interval 0.79-0.91]). The receiver operator characteristic curve for postoperative alpha angle demonstrated acceptable discrimination between patients returning to sport and patients not returning to sport with an area under the curve of 0.71 and a threshold value of 46°. Athletes with a postoperative alpha angle ≤46° returned to sport at significantly higher rates than those with a postoperative alpha angle >46° [(P < .001, S > 9.97 [odds ratio 6.3, 95% confidence interval 2.6-15.2]).

CONCLUSIONS

Postoperative alpha angle was identified as a predictor of return to sport in athletes. The odds of returning to sport were 6.3 times greater in athletes with postoperative alpha angles ≤46° compared with athletes with angles >46°.

LEVEL OF EVIDENCE

III, retrospective cohort study.