Labral reconstruction with polyurethane implant

Polyurethane Scaffold vs Fascia Lata Autograft for Hip Labral Reconstruction: Comparison of Femoroacetabular Biomechanics

Background

The integrity of the acetabular labrum is critical in providing normal function and minimizing hip degeneration and is considered key for success in today's hip preservation algorithm. Many advances have been made in labral repair and reconstruction to restore the suction seal.

Purpose/Hypothesis

To compare the biomechanical effects of segmental labral reconstruction between the synthetic polyurethane scaffold (PS) and fascia lata autograft (FLA). Our hypothesis was that reconstruction with a macroporous polyurethane implant and autograft reconstruction of fascia lata would normalize hip joint kinetics and restore the suction seal.

Study Design

Controlled laboratory study.

Methods

Ten cadaveric hips from 5 fresh-frozen pelvises underwent biomechanical testing with a dynamic intra-articular pressure measurement system under 3 conditions: (1) intact labrum, (2) reconstruction with PS after a 3-cm segmental labrectomy, then (3) reconstruction with FLA. Contact area, contact pressure, and peak force were evaluated in 4 positions: 90º of flexion in neutral, 90º of flexion plus internal rotation, 90º of flexion plus external rotation, and 20º of extension. A labral seal test was performed for both reconstruction techniques. The relative change from the intact condition (value = 1) was determined for all conditions and positions.

Results

PS restored contact area to at least 96% of intact (≥0.96; range, 0.96-0.98) in all 4 positions, and FLA restored contact area to at least 97% (≥0.97; range, 0.97-1.19). Contact pressure was restored to ≥1.08 (range, 1.08-1.11) with the PS and ≥1.08 (range, 1.08-1.10) with the FLA technique. Peak force returned to ≥1.02 (range, 1.02-1.05) with PS and ≥1.02 (range, 1.02-1.07) with FLA. No significant differences were found between the reconstruction techniques in contact area in any position (P > .06), with the exception that FLA presented greater contact area in flexion plus internal rotation as compared with PS (P = .003). Suction seal was confirmed in 80% of PSs and 70% of FLAs (P = .62).

Conclusion

Segmental hip labral reconstruction using PS and FLA reapproximated femoroacetabular contact biomechanics close to the intact state.

Clinical Relevance

These findings provide preclinical evidence supporting the use of a synthetic scaffold as an alternative to FLA and therefore avoiding donor site morbidity.

Hip Labral Reconstruction With a Polyurethane Scaffold: Restoration of Femoroacetabular Contact Biomechanics

Background:

Many advances have been made in hip labral repair and reconstruction and in the restoration of the suction seal.

Purpose/Hypothesis:

The purpose of this study was to evaluate the biomechanical effects of segmental labral reconstruction with a synthetic polyurethane scaffold (PS) in comparison with segmental labrectomy. Our hypothesis was that reconstruction with a icroporous polyurethane implant would normalize joint kinetics of the hip and restore the suction seal.

Study Design:

Controlled laboratory study.

Methods:

We used 10 hips from 5 fresh-frozen pelvises with an intact acetabular labrum without osteoarthritis. Using an intra-articular pressure measurement system, the contact area, contact pressure, and peak force were assessed for the following conditions: intact labrum, partial anterosuperior labrectomy, and PS reconstruction. For each condition, all specimens were analyzed in 4 positions (90° of flexion, 90° of flexion and internal rotation, 90° of flexion and external rotation, and 20° of extension) and underwent a labral seal test. The relative change from the intact condition was determined for all conditions and positions.

Results:

Compared with the intact labrum, labrectomy resulted in a significant decrease in the contact area (P < .001) and a significant increase in the peak force (P < .001) and contact pressure (P < .001) across all positions. Compared with labrectomy, PS reconstruction resulted in a significant increase in the contact area (P < .001) and a significant decrease in the contact pressure (P ≤ .02) and peak force (P < .001) across all positions. Compared with the intact labrum, PS reconstruction restored the contact area and peak force to normal values in all positions (P > .05), whereas the contact pressure was significantly decreased compared with labrectomy (P < .05) but did not return to normal values. The labral seal was lost in all specimens after labrectomy but was restored in 80% of the specimens after PS reconstruction.

Conclusion:

Femoroacetabular contact biomechanics significantly worsened after partial labrectomy; reconstruction using a PS restored the contact area and peak force to the intact state and improved the contact pressure increases seen after partial labrectomy. The contact area and peak force were normalized, and the labral seal was re-established in most cases.

Clinical Relevance:

This study provides biomechanical evidence for the use of a scaffold for labral reconstruction.

[Labral lesions in femoroacetabular impingement syndrome: evidence-based treatment]

BACKGROUND

The acetabular labrum and the adjacent rim cartilage are the primary targets of primary or secondary degeneration processes in the hip joint. Currently, femoroacetabular impingement syndrome (FAIS) is considered the main mechanical pathology leading to chondrolabral damage. The treatment options for labrum tears range from a debridement/resection, repair to augmentation or transplantation.

AIM

Description of surgical treatment options for pathologic changes of the acetabulare labrum and their results with a focus on FAIS.

MATERIALS AND METHODS

A literature search was performed on https://pubmed.ncbi.nlm.nih.gov using the following key words: hip, labrum, therapy, resection, repair, augmentation, reconstruction.

RESULTS

The different surgical procedures as labrum therapy reduce pain and increase the joint function. Labral repair, augmentation, and reconstruction tend to have better results compared to resection but are associated with a higher rate of postoperative intraarticular adhesions.

DISCUSSION

In addition to reducing pain and improving function, the goal of surgical treatment of labrum lesions should be to maintain the functions of the labrum. The labrum should be preserved, in cases of adequate tissue quality and width. In the setting of resective procedures, the resection should be limited to the unstable parts of the labrum. The results of labral augmentation and reconstruction are promising, allowing these procedures to be considered for patients with ongoing symptoms in the revision situation with labral defects or an insufficient residual labrum.