Partial labral resection caused significant decreases in intra-articular fluid pressurization. Through type labral suture repair restored the fluid pressurization better than looped type repairs. Labral reconstruction significantly improved pressurization to levels similar to the intact state. This study demonstrated the effect of labral tears and partial resections on intra-articular fluid pressurization via the hip fluid seal, and it also demonstrated improvements in pressurization seen with through type labral repairs and labral reconstructions.

In situ repair may be an effective treatment to improve tibiofemoral contact profiles after an avulsion of the posterior root of the lateral meniscus or a complete radial tear adjacent to the root. In situ repairs should be further investigated clinically as an alternative to partial lateral meniscectomy.

Adjustable-length loop devices may need to be retensioned after cycling the knee and fixing the tibial side to account for the increased initial displacement seen with these devices.

The acetabular labrum was the primary hip stabilizer to distraction forces at small displacements (1-2 mm). Partial labral resection significantly decreased the distractive strength of the hip fluid seal. Labral reconstruction significantly improved distractive stability, compared to partial labral resection. The results of this study may provide insight into the relative importance of the capsule and labrum to distractive stability of the hip and may help to explain hip microinstability in the setting of labral disease.

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Objectives:Complete radial tears near the medial meniscus posterior root attachment site disrupt the circumferential integrity of the meniscus (similar to a posterior root avulsion). These tears can compromise the circumferential integrity and have been reported in biomechanical studies to simulate the meniscectomized state. The purpose of the study was to quantify the tibiofemoral contact load and contact area changes that occur in cadaveric knees from complete posterior horn radial tears and subsequent repairs of the medial meniscus adjacent to the posterior root attachment site. Methods: Six non-paired fresh-frozen human cadaveric knees each underwent 45 different testing conditions: 9 medial meniscus conditions (intact, root avulsion, root repair, serial radial tear and in-situ repair at 3, 6, and 9 mm from the root attachment site) at 5 flexion angles (0°, 30°, 45°, 60° and 90°); under a 1000-N axial load. Tekscan sensors were used to measure contact area and pressure in the medial and lateral compartments. Results: The medial meniscus root avulsion and all radial tear conditions resulted in significantly decreased contact area and increased mean contact pressure compared with the intact state for knee flexion angles beyond 0° (P < .05). Medial Compartment Contact Area Individual comparisons of meniscus conditions for results at 30°, 45°, 60° and 90° of flexion demonstrated the following. At each angle, the root avulsion and 3, 6 and 9 mm radial tears resulted in a significant reduction (range 33%-45% decrease) in medial compartment contact area. Medial Compartment Contact Pressure Individual comparisons of meniscus conditions were performed at 30°, 45°, 60° and 90° of flexion. At each angle, the root avulsion and all radial tears resulted in a significant increase in average contact pressure (range 46%-110%) when compared to the intact meniscus. Root Repair and In-situ Repairs The root repair and in-situ repairs restored contact area and pressure to levels statistically indistinguishable from the intact meniscus, and increased contact area and decreased contact pressure when compared to the corresponding tear conditions (Figure

Biomechanically, the results show that both suture anchor and direct suture repair of the ATFL provide similar strength and stiffness. Unfortunately, these methods provide less than half the strength and stiffness of the native ATFL at time zero. As a result, regardless of the repair method, it is necessary to sufficiently protect the repair to avoid premature failure.

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