A Biomechanical Comparison of 2 Hip Capsular Reconstruction Techniques: Iliotibial Band Autograft Versus Achilles Tendon Allograft

Abstract

Background: Several techniques for hip capsular reconstruction have been described to address gross instability or microinstability due to capsular deficiency. However, objective biomechanical data to support their use are lacking. Purpose: To compare the kinematic effect of 2 capsular reconstruction techniques (iliotibial band [ITB] graft and Achilles tendon graft). Kinematic effect encompassed rotational range of motion (ROM) as well as joint translation in the coronal, sagittal, and axial planes. Study Design: Controlled laboratory study. Methods: 8 paired, fresh-frozen hemi-pelvises (16 hips) were tested on a custom-designed joint motion simulator in the intact state and after capsulectomy. Pairs were randomly allocated to either ITB or Achilles reconstruction and retested. Testing was performed at 0°, 45°, and 90° of flexion. Internal-external rotation (IR-ER) torques and abduction-adduction torques of 3 N·m were applied to the femur via a load cell at each position, and rotational ROM and joint translation in the coronal, sagittal, and axial planes were recorded. Results: At 45° and 90°, there was a significant effect of the condition of the hip on the total IR-ER ( P = .004, effect size [ES] = 0.305; and P < .001, ES = 0.497; respectively). At 45°, mean ± SD total rotation was significantly greater for the capsulectomy (59.7°± 15.9°) state compared with intact (53.3°± 13.2°; P = .007). At 90°, reconstruction significantly decreased total rotation to 49.0°± 18.9° compared with a mean total rotation of 52.8°± 18.7° after capsulectomy ( P = .02). No difference was seen in the total abduction-adduction of the hip between conditions. Comparisons of the 2 different reconstruction techniques showed no significant differences in total IR-ER or abduction-adduction ROM or joint translation in the coronal, sagittal, or axial planes. For translation, at both 0° and 45° there was a statistically significant effect of the condition on the medial-lateral translation ( P = .033; ES = 0.204). Reconstruction, independent of technique, was successful in significantly decreasing ( P = .030; P = .014) the mean medial-lateral translation at 0° and 45° of hip flexion from 5.2 ± 3.8 mm and 5.6 ± 4.0 mm to 2.8 ± 1.9 mm and 3.9 ± 3.2 mm, respectively. Conclusion: The integrity of the native hip capsule played a significant role in rotational stability, where capsulectomy significantly increased rotational ROM. Both ITB and Achilles reconstruction techniques restored normal rotational ROM of the hip at 90° of flexion as well as coronal plane stability at 0° and 45° of hip flexion. No differences were seen between ITB and Achilles reconstruction techniques. Clinical Relevance: Both capsular reconstruction techniques provide comparable joint kinematics, restoring rotation and translation to normal values with the exception of rotational ROM at 45°, which remained significantly greater than the intact state. The most significant results were the rotational stability at 90° of hip flexion and coronal plane stability at 0° and 45° of hip flexion, which were significantly improved compared with the capsulectomy state.

Is there enough evidence to support hip capsular reconstruction? A systematic review of biomechanical studies

“…investigated eight paired, cadaveric pelvises and recorded rotational ROM and joint translation in the coronal, sagittal and axial planes while applying internal–external rotation and abduction–adduction rotation torques at different degrees of flexion [ 33 ]. Pairs were randomly allocated to either ITB or Achilles reconstruction and were compared to intact and capsulectomy conditions [ 33 ]. Philippon et al .…”

“…Likewise, Pasic et al . showed that at 90° of hip flexion, both reconstruction techniques utilizing ITB and Achilles tendon had significantly lower degrees of total rotation than the capsulectomy state with values similar to the intact state [ 33 ]. Increased coronal plane stability in the hip was also observed with capsular reconstruction, especially with the Achilles tendon allograft [ 33 ].…”

“…[ 39 ]. For studies that reported ROM, the percent increase was calculated from the mean and standard deviation of groups [ 29 , 33 ]. All computations for P values were carried out using a linear random effect model using the log scale data.…”

Arthroscopic Anchor-Based Hip Capsular Reconstruction Without Graft Augmentation

“…In a biomechanical study of 8 paired hemi-pelvises (16 hips), Pasic et al. 13 evaluated the hip joint range of motion in the intact state, after capsulectomy, and in the reconstructed state. Pairs were randomly allocated to either iliotibial band or Achilles reconstruction groups.…”

“…The authors found no difference in range of motion based on graft type. 13 Although early results of our capsular reconstruction technique have been promising in our clinical practice, studies reporting medium- to long-term patient-reported outcomes and biomechanical studies are necessary to support capsular reconstruction without the use of a graft. Given our encouraging early results, we will continue to perform anchor-based reconstruction without allograft augmentation in select patients with capsular deficiency in those who have adequate femoral sided capsular tissue for complete, watertight closure.…”