A T-Capsulotomy Provides Increased Hip Joint Visualization Compared to an Extended Interportal Capsulotomy: Implications For Improved Capsular Management

OBJECTIVES: Growing biomechanical and clinical evidence suggests that the treating hip arthroscopist must balance creating a capsulotomy large enough to adequately address underlying pathology while not compromising the integrity of the hip capsule, which can potentially lead to iatrogenic hip instability. The purpose of this study was to compare the cross-sectional area (CSA) of joint visualization between interportal and T-capsulotomies. METHODS: 12 fresh-frozen cadaveric hips were dissected to their capsuloligamentous complexes and fixed in a custom apparatus in neutral hip position. Eight hips underwent sequential interportal capsulotomies at lengths of 2, 4, 6, and 8 cm. Four hips underwent sequential T-capsulotomies, 4 cm interportal and 2 cm T-capsulotomy (Half-T), then expansion of the T-capsulotomy to 4 cm (Full-T). A high-resolution digital photograph was taken of the capsulotomies from a standardized distance and angle with a calibration marker in place. Joint exposure gained from each capsulotomy was determined by measuring joint cross-sectional area (CSA) with ImageJ software (NIH, Bethesda, MD). Comparisons were made using t-tests and analysis of variance (ANOVA). RESULTS: There was no significant difference in the age of cadaveric hips in both groups (65.6 ± 10.83 years: interportal vs 63.3 ± 2.5 years: T capsulotomy, p=0.53). There was statistically significant increase in CSA visualization with each increase in length (2cm: 0.58 ± 0.21cm2; 4cm: 2.14 ± 0.48 cm2; 6cm: 3.57±0.96 cm2; and 8cm: 4.22 ± 1.16 cm2, p<0.001 for all). For the T-capsulotomy group the average CSA visualization significantly increased from 3.54 ± 0.86 cm2 for the Half-T to 6.63 ± 0.90 cm2 for the Full-T (p=0.005). Half-T CSA visualization was statistically comparable to the 6 cm and 8 cm interportal capsulotomy (p=0.09, ). The Full-T had significantly superior CSA visualization area as compared to the 6 cm and 8 cm interportal capsulotomies (p<0.0001 for both). CONCLUSION: When improved joint exposure is necessary, T-capsulotomy should be considered given the decreased morbidity of cutting the IFL inline with its fibers and the significantly increased joint visualization compared to extending the interportal capsulotomy.