The role of the iliofemoral ligament as a stabilizer of the hip joint

Differentiation of strains in the lateral and medial bands of the iliofemoral ligament: A segmental approach

Iliofemoral ligament strains have been assessed in a circumscribed portion, limiting the information regarding the strains in the proximal, mid and distal portions. The purpose of this study is to describe the longitudinal and transversal strain within the proximal, mid and distal portions of the lateral and medial bands of the iliofemoral ligament. Ten fresh cadaveric specimens were assessed. The iliofemoral ligaments were divided into medial and lateral bands. Hemispherical beads (2.6 mm) were placed on the lateral and medial borders of each band. Four positions were assessed: abduction, extension, internal and external rotations combined with extension. The hemispherical beads were scanned at the end range of motion using a laser scanner. The three-dimensional position of each bead was used to estimate longitudinal and transversal strains. A three-factor ANOVA was used to compare movements, borders, and portions within each ligament for longitudinal strains. A one-way ANOVA was used to compare transversal strains between portions. This technique showed mean reliability (ICC: 2, 1) of 0.90 ± 0.06. The external rotation showed the highest strains in both ligaments (p < 0.05). Abduction showed a significant difference between the lateral and medial borders in both bands (p = 0.001). Eight movement-border combinations showed a significant difference between proximal, medial, and lateral portions (p < 0.005). According to our results, there is a clear effect of portions (proximal, mid and distal) within the ligament and movements. Abduction shows the lowest strains longitudinally but the largest strains transversally. Although we do not know the impact of this phenomenon, future studies should assess the strains following hip arthroscopies. The latter might improve the impact of this procedure on hip biomechanics. Lastly, the iliofemoral ligament should be assessed using a segmental approach rather than as a complete unit.

A higher proportion of patients may reach the MCID with capsular closure in patients undergoing arthroscopic surgery for femoroacetabular impingement: a systematic review and meta-analysis

PURPOSE

The purpose of this review is to provide a summary of the techniques and outcomes of various capsular management strategies in patients undergoing hip arthroscopy for femoroacetabular impingement (FAI). The information this review provides on capsular management strategies will provide surgeons with operative guidance and decision-making when managing patients with FAI lesions arthroscopically.

METHODS

Three databases MEDLINE, EMBASE, and PubMed were searched from database inception to November 2nd 2021, for literature addressing capsular management of patients undergoing hip arthroscopy for FAI. All level I-IV data on capsular management strategy as well as postoperative functional outcomes were recorded. A meta-analysis was used to combine the mean postoperative functional outcomes using a random-effects model.

RESULTS

Overall, there were a total of 36 studies and 4744 patients included in this review. The mean MINORS score was 10.7 (range 8-13) for non-comparative studies and 17.6 (range 15-20) for comparative studies. Three comparative studies in 1302 patients examining the proportion of patients reaching the MCID for the mHHS score in patients undergoing interportal capsulotomy with either capsular repair or no repair found that the capsular repair group had a higher odds ratio of reaching the MCID at 1.46 (95% CI 0.61-3.45, I² = 67%, Fig. 2, Table 3); however, this difference was not significant with a p value of 0.39. When looking at only level 1 and 2 studies, four studies in 1308 patients reporting on the mHHS score in patients undergoing capsular closure regardless of capsulotomy type, found a pooled standardized mean difference in the mHHS score of 2.1 (95% CI 1.7-2.55, I² = 70%, Fig. 3), while four studies in 402 patients reporting on the mHHS score in patients not undergoing capsular closure regardless of capsulotomy type found a pooled standardized mean difference in the mHHS score of 1.46 (95% CI 1.2-1.7, I² = 30%, Fig. 4).

CONCLUSION

This review may demonstrate improved postoperative outcomes in patients undergoing complete capsular closure regardless of capsulotomy type based on postoperative mHHS score. Furthermore, this review may suggest improved postoperative outcomes after closure of an interportal capsulotomy. There are limited published outcome data regarding T-type capsulotomy without closure. This review provides surgeons with operative guidance on capsular management strategies when treating patients with FAI lesions arthroscopically.

LEVEL OF EVIDENCE

IV.

Capsular Mechanics After Periacetabular Osteotomy for Hip Dysplasia

BACKGROUND

Hip dysplasia is characterized by insufficient acetabular coverage around the femoral head, which leads to instability, pain, and injury. Periacetabular osteotomy (PAO) aims to restore acetabular coverage and function, but its effects on capsular mechanics and joint stability are still unclear. The purpose of this study was to examine the effects of PAO on capsular mechanics and joint range of motion in dysplastic hips.

METHODS

Twelve cadaveric dysplastic hips (denuded to bone and capsule) were mounted onto a robotic tester and tested in multiple positions: (1) full extension, (2) neutral 0°, (3) flexion of 30°, (4) flexion of 60°, and (5) flexion of 90°. In each position, the hips underwent internal and external rotation, abduction, and adduction using 5 Nm of torque. Each hip then underwent PAO to reorient the acetabular fragment, preserving the capsular ligaments, and was retested.

RESULTS

The PAO reduced internal rotation in flexion of 90° (∆IR = -5°; p = 0.003), and increased external rotation in flexion of 60° (∆ER = +7°; p = 0.001) and flexion of 90° (∆ER = +11°; p = 0.001). The PAO also reduced abduction in extension (∆ABD = -10°; p = 0.002), neutral 0° (∆ABD = -7°; p = 0.001), and flexion of 30° (∆ABD = -8°; p = 0.001), but increased adduction in neutral 0° (∆ADD = +9°; p = 0.001), flexion of 30° (∆ADD = +11°; p = 0.002), and flexion of 60° (∆ADD = +11°; p = 0.003).

CONCLUSIONS

PAO caused reductions in hip abduction and internal rotation but greater increases in hip adduction and external rotation. The osseous acetabular structure and capsule both play a role in the balance between joint mobility and stability after PAO.