Intra-articular Volume Reduction With Arthroscopic Plication for Capsular Laxity of the Hip: A Cadaveric Comparison of Two Surgical Techniques
Purpose: To compare intracapsular volume reduction between interportal capsular shift and T-capsulotomy plication in a cadaveric model.
Methods: Twelve pair-matched specimens were randomized into T-capsulotomy plication or interportal capsular shift. T-capsulotomy was performed using a 2-cm interportal and 2-cm bisecting, longitudinal limb to the intertrochanteric line. Plication was performed utilizing 5-mm bites on either side of the capsulotomy with arthroscopic knot tying technique standard alternating half hitches. Pair-matched interportal capsular shift specimens underwent 5-cm interportal capsulotomy, and capsular shift was performed utilizing 5 nonabsorbable sutures placed in 45° orientation at 5 mm from the capsulotomy margin. With each specimen in a position of slight flexion and adduction, a spinal needle was used to inject methylene blue-colored saline solution intra-articularly; the volcano method was used to measure capsular volume before and after each respective plication technique. Mean absolute volumes and relative volumetric reduction for each technique were quantified and compared to determine statistical significance.
Results: At baseline, there were no statistically significant differences in capsular volume between pair-matched specimens (T-capsulotomy plication, 42.5 ± 5.1 mL; interportal capsular shift, 45.0 ± 88.6 mL; P = .555). After capsulotomy and secondary plication, both the T-capsulotomy (post: mean = 32.5 ± 8.0 mL; P < .001) and interportal capsulotomy groups (post: mean = 29.4 ± 10.0; P < .0001) demonstrated significant decreases in capsular volume, with average reductions of 10.0 ± 3.3 mL and 15.6 ± 3.2 mL, respectively. Although the interportal capsular shift (35.9% ± 11.3%) demonstrated greater volumetric reduction relative to baseline when compared with the T-capsular plication (24.5% ± 10.8%), these results were not significant (P = .104).
Conclusions: Both T-capsular plication and interportal capsular shift produce statistically significant reductions in overall hip capsular volume. Although the interportal capsular shift may generate modestly higher degrees of capsular reduction, the comparative biomechanical repercussions of each technique are not currently known.
Clinical relevance: Irrespective of arthroscopic technique, capsular plication with 5-mm bites decreases capsular volume by approximately one-third to one-fourth that of baseline measures.