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Purpose: To evaluate the change in hip distractive stability after a cam over-resection, labral tear, repair, labrectomy, or circumferential 6-mm or 10-mm labral reconstruction in a biomechanical model., Methods: Ten fresh-frozen matched pair human cadaveric hips were analyzed using a materials testing system to measure the force and distance required to disrupt the suction seal of the hip (1) with an intact capsule and labrum, (2) after a capsulectomy and labral repair, (3) after a capsulectomy, 5-mm cam over-resection and labral repair, (4) after a capsulectomy, 5-mm cam over-resection and labral tear, (5) after a capsulectomy, 5-mm cam over-resection and labrectomy, and (6) after a capsulectomy, 5-mm cam over-resection, and a 6- or 10-mm circumferential labral reconstruction with iliotibial band (5 hips each). Each specimen was retested at 0° flexion, 45° flexion, and 45° flexion and 15° internal rotation and analyzed using non-parametric statistical methods., Results: The Friedman test of differences was significant among structural conditions and hip positions (P = 0.001). In all positions, the resistive force that opposed the disruption of the suction seal in an intact hip was significantly greater compared to all other conditions. The resistive force for the capsulectomy, 5-mm cam over-resection and labrectomy condition was significantly less compared to almost all other conditions and hip positions. A qualitative suction seal was achieved in 20% of hip specimens with a 6-mm labral reconstruction while a seal was in achieved 60% of specimens with a 10-mm labral reconstruction., Conclusions: After a cam over-resection, a circumferential labral reconstruction improves the distractive stability of a labral deficient hip, comparable to a labral repair or tear in a biomechanical model., Clinical Relevance: Circumferential labral reconstruction may be a viable treatment option for patients with ongoing symptoms after hip arthroscopy with evidence of a cam over-resection and a deficient labrum., (Copyright © 2024. Published by Elsevier Inc.)

Purpose: To evaluate the change in hip distractive stability after a capsulotomy, labral tear, and simultaneous repair of both the capsule and the labrum in a biomechanical model., Methods: Ten fresh-frozen human cadaveric hips were analyzed using a materials testing system to measure the distractive force and distance required to disrupt the hip suction seal under the following conditions: (1) native intact capsule and labrum, (2) 2- or 4-cm interportal capsulotomy (IPC), (3) labral tear, (4) T extension, (5) labral repair, (6) T extension repair, and (7) IPC repair. Each specimen was retested at 0° of flexion, 45° of flexion, and 45° of flexion with 15° of internal rotation., Results: A significantly higher distractive force was required to rupture the suction seal in the intact condition compared with IPC (P = .012; 95% confidence interval [CI], 4.9-42.4); IPC and labral tear (P = .002; 95% CI, 11.3-49.4); IPC, labral tear, and T extension (P = .001; 95% CI, 13.9-51.5); IPC, labral repair, and T extension (P < .001; 95% CI, 20.8-49.7); IPC, labral repair, and T extension repair (P = .002; 95% CI, 12.5-52.4); and IPC repair, labral repair, and T extension repair (P = .01; 95% CI, 5.8-46.1). The IPC condition required a higher distractive force in isolation than when combined with a labral tear (P = .14; 95% CI, 1.2-12.0), T extension (P = .005; 95% CI, 2.8-15.3), or labral repair (P = .002; 95% CI, 4.4-18.8)., Conclusions: The distractive resistance of an intact hip capsule and labrum was not restored once the soft tissues were violated, despite labral repair with a loop technique and capsular repair with interrupted figure-of-8 sutures., Clinical Relevance: Time-zero complete capsular repair with concomitant labral repair may not be adequate to restore distractive hip stability after hip arthroscopy, reinforcing the use of postoperative precautions in the early postoperative period., Competing Interests: Disclosures The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: R.M.D. reports equipment, drugs, or supplies were provided by Smith & Nephew in kind support. K.C.G.N. reports that financial support was provided by the Natural Sciences and Engineering Research Council of Canada Discovery Grant. All other authors (A.J.H., S.A.S.G., B.A.L.) declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Purpose: To evaluate the impact of capsular management on joint constraint and femoral head translations during simulated activities of daily living (ADL)., Methods: Using 6 (n = 6) cadaveric hip specimens, the effect of capsulotomies and repair was then evaluated during simulated ADL. Joint forces and rotational kinematics associated with gait and sitting, adopted from telemeterized implant studies, were applied to the hip using a 6-degrees of freedom (DOF) joint motion simulator. Testing occurred after creation of portals, interportal capsulotomy (IPC), IPC repair, T-capsulotomy (T-Cap), partial T-Cap repair, and full T-Cap repair. The anterior-posterior (AP), medial-lateral (ML), and axial compression DOFs were operated in force control, whereas flexion-extension, adduction-abduction, and internal-external rotation were manipulated in displacement control. Resulting femoral head translations and joint reaction torques were recorded and evaluated. Subsequently, the mean-centered range of femoral head displacements and peak signed joint restraint torques were calculated and compared., Results: During simulated gait and sitting, the mean range of AP femoral head displacements with respect to intact exceeded 1% of the femoral head diameter after creating portals, T-Caps, and partial T-Cap repair (Wilcoxon signed rank P < .05); the mean ranges of ML displacements did not. Deviations in femoral head kinematics varied by capsule stage but were never very large. No consistent trends with respect to alterations in peak joint restrain torques were observed., Conclusions: In this cadaveric biomechanical study, capsulotomy and repair minimally affected resultant femoral head translation and joint torques during simulated ADLs., Clinical Relevance: The tested ADLs appear safe to perform after surgery, regardless of capsular status, because adverse kinematics were not observed. However, further study is required to determine the importance of capsular repair beyond time-zero biomechanics and the resultant effect on patient-reported outcomes., (Copyright © 2023 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.)

Purpose: To assess how biomechanical gait parameters (kinematics, kinetics, and muscle force estimations) differ between patients with cam-type femoroacetabular impingement (FAI) and healthy controls, through a systematic search., Methods: A systematic review of the literature from PubMed, Scopus, and Medline and EMBASE via OVID SP was undertaken from inception to April 2020 using PRISMA guidelines. Studies that described kinematics, kinetics, and/or estimated muscle forces in cam-type FAI were identified and reviewed., Results: The search strategy identified 404 articles for evaluation. Removal of duplicates and screening of titles and abstracts resulted in full-text review of 37 articles, with 12 meeting inclusion criteria. The 12 studies reported biomechanical data on a total of 173 cam-FAI (151 cam-specific, 22 mixed-type) patients and 177 healthy age-, sex-, and body mass index-matched controls. Patients with cam FAI had reduced hip sagittal plane range of motion (mean difference -3.00° [-4.10, -1.90], P < .001), reduced hip peak extension angles (mean difference -2.05° [-3.58, -0.53] , P = .008), reduced abduction angles in the terminal phase of stance, and reduced iliacus and psoas muscle force production in the terminal phase of stance compared to the control groups. Cam FAI cohorts walked at a slower speed compared with controls., Conclusions: In conclusion, patients with cam-type FAI exhibit altered sagittal and frontal plane kinematics as well as altered muscle force production during level gait compared to controls. These findings will help guide future research into gait alterations in FAI and how such alterations may contribute to pathologic progression and furthermore, how such alterations can be modified for therapeutic benefit., Level of Evidence: Systematic review of Level III studies., (Copyright © 2021 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.)

Purpose: The purpose of this in vitro cadaveric study was to examine the contributions of each surgical stage during cam femoroacetabular impingement (FAI) surgery (i.e., intact-cam hip, T-capsulotomy, cam resection, and capsular repair) toward hip range of motion, translation, and microinstability., Methods: Twelve cadaveric cam hips were denuded to the capsule and mounted onto a robotic tester. The hips were positioned in several flexion positions-full extension, neutral (0°), 30° of flexion, and 90° of flexion-and performed internal-external rotations to 5 Nm of torque in each position. The hips underwent a series of surgical stages (T-capsulotomy, cam resection, and capsular repair) and were retested after each stage. Changes in range of motion, translation, and microinstability (overall translation normalized by femoral head radius) were measured after each stage., Results: Regarding range of motion, cam resection increased internal rotation at 90° of flexion (change in internal rotation = +6°, P = .001) but did not affect external rotation. Capsular repair restrained external rotation compared with the cam resection stage (change in external rotation = -8° to -4°, P ≤ .04). In terms of translation, the hip translated after cam resection at 90° of flexion in the medial-lateral plane (change in translation = +1.9 mm, P = .04) relative to the intact and capsulotomy stages. Regarding microinstability, capsulotomy increased microinstability in 30° of flexion (change in microinstability [Δ M ] = +0.05, P = .003), but microinstability did not further increase after cam resection. At 90° of flexion, microinstability did not increase after capsulotomy (Δ M  = +0.03, P = .2) but substantially increased after cam resection (Δ M  = +0.08, P = .03), accounting for a 31% change with respect to the intact stage., Conclusions: Cam resection increased microinstability by 31% during deep hip flexion relative to the intact hip. This finding suggests that iatrogenic microinstability may be due to separation of the labral seal and resected contour of the femoral head., Clinical Relevance: Our in vitro study showed that, at time zero and prior to postoperative recovery, excessive motion after cam resection could disrupt the labral seal. Complete cam resection should be performed cautiously to avoid disruption of the labral seal and postoperative microinstability., (Copyright © 2020 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.)