Capsular Repair During Hip Arthroscopy Demonstrates Restoration of Axial Distraction Resistance in an in Vivo Intraoperative Testing Model

Abstract

Background:Cadaveric models demonstrate that failure of hip capsular repair is dependent on the robustness of the repair construct. In vivo data on capsular repair construct efficacy are limited. We investigated the effect of a figure-of-8 capsular repair on hip distraction resistance relative to native and post-capsulotomy states. We hypothesized that an unrepaired capsulotomy would demonstrate increased axial distraction compared with the native state and that capsular repair would restore distraction resistance to native levels.Methods:Patients undergoing primary hip arthroscopy by a single surgeon were prospectively enrolled between March 2020 and June 2020. Prior to any instrumentation, fluoroscopic images of the operative hip were obtained at 12.5-lbs (5.7-kg) traction intervals, up to 100 lbs (45.4 kg). Anterolateral, modified anterior, and distal anterolateral portals were established. Following interportal capsulotomy, labral repair, and osteochondroplasty, fluoroscopic images were reobtained at each traction interval. Capsular repair was performed with use of a figure-of-8 suture configuration. Traction was reapplied and fluoroscopic images were again obtained. Joint distraction distance was measured at each traction interval for all 3 capsular states. Anteroposterior pelvic radiographs were utilized to scale fluoroscopic images to obtain joint space measurements in millimeters.Results:A total of 31 hips in 31 patients were included. Capsulotomy resulted in significant increases in distraction distance from 25 (11.3 kg) to 100 lbs of traction compared with both native and capsular repair states (all comparisons, p ≤ 0.017). Capsular repair yielded a significantly greater distraction distance compared with the native state at 37.5 lbs (17.0 kg; 5.49 versus 4.98 mm, respectively; p = 0.012) and 50 lbs (22.7 kg; 6.08 versus 5.35 mm; p < 0.001). The mean difference in distraction distance between native and capsular repair states from 25 to 100 lbs of traction was 0.01 mm.Conclusions:This in vivo model demonstrates that an unrepaired interportal capsulotomy significantly increases axial distraction distance compared with the native, intact hip capsule. Performing a complete capsular closure reconstitutes resistance to axial distraction intraoperatively. Future research should evaluate the in vivo effects and associated clinical outcomes of other published capsular repair techniques and assess the durability of capsular repairs over time.

Patients With Simple Posterior Hip Dislocations Have Higher Rates of Hip Dysplasia and Borderline Dysplasia

“…Although the trauma literature is limited in this regard, numerous studies on total hip arthroplasty have demonstrated the importance of capsular repair on the rates of prosthetic hip dislocations. 32,33 In addition, there is ample evidence supporting the importance of capsular repair to restore stability after arthroscopic hip procedures 34,35 There were no documented redislocations in either group in this study, but it is likely that the underlying acetabular under coverage along with capsular injury may put these patients at increased risk of dislocation. In follow-up, patients should be counseled on the risks of redislocation and recognition of hip positions that will place these patients at risk of redislocation.…”

Superior outcomes after arthroscopic treatment of femoroacetabular impingement and labral tears with closed versus open capsule

“…Although biomechanical studies favor complete closure of the hip capsule for better restoration of the native joint kinematics [4,15,24,28,34], some clinical studies are not in The major concern about capsular management after hip arthroscopy is postoperative instability. Several case reports discussed postoperative dislocation and subluxation after arthroscopic hip surgery without the attempt of capsular repair due to preoperative dysplasia and/or failure of labral repair [3,6,22,23].…”

“…Although biomechanical studies favor complete closure of the hip capsule for better restoration of the native joint kinematics [4, 15, 24, 28, 34], some clinical studies are not in agreement. According to Atzmon et al [2], capsular closure had no significant influence on clinical outcome scores of patients who underwent arthroscopic hip surgery for FAI or labral tear.…”

Relationship Between Hip Capsular Thickness and Instability After Previous Hip Arthroscopic Surgery: A Matched-Cohort Analysis

“…previously shown to be important in terms of restoring native capsule biomechanics 25 and improving patient outcomes in the postoperative setting, furthering the importance of the hip capsule in overall hip stability. 4,10,11,34 While the hip is regarded as an inherently stable joint, there has been recent investigation into the characterization of hip instability; these topics have come to the forefront as a result of increased recognition of their clinical importance.…”