Labral augmentation with ligamentum capitis femoris: presentation of a new technique and preliminary results

Tissue Integration and Chondroprotective Potential of Acetabular Labral Augmentation with Autograft Tendon: Study of a Porcine Model

BACKGROUND

The aim of this study was to explore the tissue healing process and changes in articular cartilage following acetabular labral augmentation in a porcine model.

METHODS

The labrum was resected unilaterally from 10 o'clock to 1 o'clock on the capsular side in 36 pigs. Eighteen pigs underwent labral augmentation (AUG group) using autologous Achilles tendon. No additional procedures were performed in the remaining pigs (control group). The pigs were killed at 6, 12, or 24 weeks postoperatively for histological assessment and measurement of the inflammatory cytokines interleukin (IL)-6, IL-1β, and tumor necrosis factor (TNF)-α in synovial fluid.

RESULTS

All autografts were well placed in the labral defect in the AUG group, and good integration of the autograft with the remnant chondrolabral junction was observed at 24 weeks; only scar tissue was observed in the control group at 6, 12, and 24 weeks. Fibrochondrocytes were concentrated at the transition between the autograft and native labrum at early time points, and the cells within the autograft labrum were predominantly fibrochondrocytes at 24 weeks. Rough and irregular articular cartilage surfaces were observed in 3 of the 6 samples in the AUG group at 24 weeks; the others appeared smooth. Focal cartilage erosion (predominantly in the acetabulum) occurred in all samples in the control group at 12 and 24 weeks. The Mankin score at 24 weeks was significantly lower in the AUG group than in the control group (mean [95% confidence interval]: 2.33 [1.06 to 3.6] versus 9 [8.06 to 9.94], p < 0.001). Likewise, the concentrations of all cytokines (in pg/mL) were significantly lower in the AUG group than in the control group at 24 weeks (IL-6: 166.6 [155.22 to 177.94] versus 245.9 [242.66 to 249.14], p < 0.001; IL-1β: 122.1 [116.4 to 127.83] versus 282.9 [280.29 to 285.51], p < 0.001; and TNF-α: 56.22 [53.15 to 59.29] versus 135 [131.66 to 138.24], p < 0.001).

CONCLUSIONS

Autograft tendon used for labral augmentation was able to integrate well with the native labrum, which may help to preserve the articular cartilage.

CLINICAL RELEVANCE

Labral augmentation with autograft tendon may be a feasible option in cases of viable labral remnants.

Tissue Regrowth and Its Vascularization Through Bone Marrow Stimulation: Microfracture at the Acetabular Rim for Irreparable Labral Tear in a Porcine Model

BACKGROUND

The treatment of irreparable acetabular labral tear remains a great challenge. Whether fibrocartilage-like tissue can regrow with sufficient volume to fill the labral defect area through bone marrow stimulation remains unknown.

PURPOSE

To characterize the healing process and vascularization course of the regrown tissue after microfracture at the acetabular rim for irreparable labral tears in a porcine model.

STUDY DESIGN

Descriptive laboratory study.

METHODS

Twelve pigs randomly underwent unilateral microfracture at the acetabular rim after the resection of a 10 mm-long section of labrum from 10 to 1 o'clock. Pigs were randomly sacrificed at 6 and 12 weeks postoperatively. The regrown tissues were harvested for macroscopic evaluation and histologic assessment. The regrown tissue was zoned into 2 halves to observe the vascular distribution: the capsular half (zone I) and the articular half (zone II). Each zone was divided into 2 parts: the peripheral part (IA and IIA) and the part attached to the acetabulum (IB and IIB).

RESULTS

At 6 weeks, all regrown tissue was hypotrophic with <50% filling of the labral defect. Fibrochondrocytes were concentrated at the interface between the acetabulum and the regrown tissue. The vascularization was equal among each part within the regrown tissue. As compared with regrown tissue at 12 weeks, proteoglycan and collagen type 1 and 2 were more evident within the regrown tissue at 6 weeks. At 12 weeks, tissue disintegration occurred in all regrown tissue with <25% filling of the labral defect area. The vascular structure could barely be observed, with few fibrochondrocytes found at the area adjacent to the acetabulum.

CONCLUSION

Fibrocartilage-like tissue did regrow with well-distributed vascular ingrowth of each part of the regrown tissue through bone marrow stimulation at the early stage. However, insufficient volume of the regrown tissue led to loss of the hip suction seal and subsequent tissue disintegration.

CLINICAL RELEVANCE

Microfracture at the rim of the acetabulum alone could not restore the morphology and function of the acetabular labrum. Nonetheless, microfracture at the acetabular rim might be a viable adjunct to labral reconstruction, as the well-distributed vascularization through bone marrow stimulation might overcome the obstacle of poor vascular ingrowth of the articular half of the autograft.

The Vascularization Course of Labral Autograft and Its Effect on Tissue Healing: Acetabular Labral Augmentation Versus Labral Reconstruction in a Porcine Model

BACKGROUND

The preservation of the native labral vascularization is assumed to be the potential advantage of acetabular labral augmentation, the effect of which remains unknown.

PURPOSE

To identify the vascular distribution within the labral autograft and its effect on the healing process between labral augmentation (AUG) and reconstruction (RECON) in a porcine model.

STUDY DESIGN

Controlled laboratory study.

METHODS

A total of 36 pigs randomly underwent unilateral labral augmentation or reconstruction (AUG group, n = 18; RECON group, n = 18). The pigs were randomly sacrificed at 6, 12, and 24 weeks postoperatively. The labral autografts were harvested for macroscopic evaluation and histologic assessment. The labral autograft was zoned into 2 halves to observe the vascular distribution: the capsular half (zone I) and the articular half (zone II). Each zone was divided into 2 parts: the peripheral part (IA and IIA) and the part attached to the acetabulum (IB and IIB).

RESULTS

At 6 weeks, there existed more vascular ingrowth in zone I, whereas zone IIB appeared nearly avascular in both groups. At 12 weeks, the area with the greatest vascularity was zone II in the RECON group and zone IA in the AUG group. The vascularity was concentrated at zones IA and IIA in both groups at 24 weeks. The labral autografts were hypertrophic with sufficient filling of the labral defect in both groups at 6 weeks. At 12 weeks, an insufficient volume of the articular half was observed in 3 of 6 labral autografts in the RECON group, while all autografts remained well integrated with the chondrolabral junction in the AUG group. At 24 weeks, unsatisfactory merging of the labral autograft with the cartilage at the articular side was found in 2 of 6 labral autografts in the RECON group, which was not observed in the AUG group despite the sufficient volume of autografts labrum in both groups.

CONCLUSION

Slow vascular ingrowth within the articular half might account for the poor healing of the reconstructed labral autograft. Labral augmentation provides the possibility of better tissue healing because of the preservation of the original chondrolabral junction compared with labral reconstruction.

CLINICAL RELEVANCE

Labral augmentation might be a feasible alternative to labral reconstruction under the condition of viable labral remnants.

[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.

Arthroscopic acetabular labrum reconstruction with capsular autograft: clinical outcome and preliminary results

To introduce a novel technique to reconstruct the acetabular labrum using capsular autograft, and to evaluate the preliminary clinical outcome, a retrospective review of a prospectively collected registry was undertaken that identified 21 patients (21 hips) who underwent arthroscopic reconstruction of the labrum by capsular autograft from January 2016 to January 2018. Modified Harris Hip Score (mHHS), Hip Outcome Score (HOS), and Hip Outcome Score-Activities of Daily Living (HOS-ADL) were recorded preoperatively and postoperatively. Clinical outcome was analyzed to evaluate the effectiveness of this technique. Twenty-one patients, with an average follow-up time of 25.4 ± 1.6 months, were included in this study: 7 patients were diagnosed with hypoplastic labrum (width <5 mm), 9 patients with complex tear of labrum, and 5 patients with degenerative labrum. The mHHS (61.3 ± 5.5 vs. 87.5 ± 4.2, P<0.001), HOS (52.5 ± 5.1 vs. 87.3 ± 3.8, P<0.001) and HOS-ADL (48.5 ± 5.8% vs. 75.2 ± 3.5%, P<0.001) between preoperative and the 6-month follow-up were significantly different. Gender exerts no influence on the outcome of mHHS, HOS and HOS-ADL. Therefore, local capsular autograft is readily available during arthroscopy with no donor-site morbidity. The reconstruction of the hip labrum may be valuable for patients with hypoplastic or dysplastic labrum, complex tear of labrum and severe degeneration. With appropriate patient selection, this technique is promising in preliminary clinical outcome.

Acetabular labral reconstruction with medial meniscal allograft: preliminary results of a new surgical technique

PURPOSE

Reconstruction of the acetabular labrum during femoroacetabular impingement (FAI) surgery is accepted when the labrum is deficient and irreparable. Here we describe a novel technique using fresh-frozen medial meniscal allograft for labral reconstruction during surgical hip dislocation for correction of pincer FAI due to acetabular overcoverage.

METHODS

The results from seven hips (six patients) that underwent this procedure with 1 year minimum follow-up, and radiographs are presented.

RESULTS

Six of the seven hips had improvements in pain, hip flexion, hip abduction, and Merle d'Aubigné-Postel scores. Only one patient with pre-existing osteoarthritis underwent reoperation with conversion to total hip arthroplasty. All digastric trochanteric osteotomies healed, and there were no cases of femoral head osteonecrosis or progression of Tönnis grades.

CONCLUSIONS

The medial meniscus is a morphologically and clinically suitable option for labral reconstruction and effectively restores the hip fluid seal.

Hip preservation

Classical indications for hip preserving surgery are: femoro-acetabular impingement (FAI) (intra- and extra-articular), hip dysplasia, slipped capital femoral epiphysis, residual deformities after Perthes disease, avascular necrosis of the femoral head.

Pre-operative evaluation of the pathomorphology is crucial for surgical planning including radiographs as the basic modality and magnetic resonance imaging (MRI) and/or computed tomography (CT) to evaluate further intra-articular lesions and osseous deformities.

Two main mechanisms of intra-articular impingement have been described:

(1) Inclusion type FAI (‘cam type’).

(2) Impaction type FAI (‘pincer type’).

Either arthroscopic or open treatment can be performed depending on the severity of deformity.

Slipped capital femoral epiphysis often results in a cam-like deformity of the hip. In acute cases a subcapital re-alignment (modified Dunn procedure) of the femoral epiphysis is an effective therapy.

Perthes disease can lead to complex femoro-acetabular deformity which predisposes to impingement with/without joint incongruency and requires a comprehensive diagnostic workup for surgical planning.

Developmental dysplasia of the hip results in a static overload of the acetabular rim and early osteoarthritis. Surgical correction by means of periacetabular osteotomy offers good long-term results.

Cite this article: EFORT Open Rev 2020;5:630-640. DOI: 10.1302/2058-5241.5.190074

Neurovascular structures of the ligament of the head of femur

The ligament of the head of femur (LHF), or ligamentum teres, is believed to provide blood supply to the head of femur and mechanical stability to the hip joint. But these functions in the adult are often debated. The existence and distribution of neurovascular structures within the ligament are not widely documented. This study examined the blood vessels and nervous tissue within the LHF to determine whether the ligament may have a vascular and proprioceptive function at the hip joint. Histological sections from the LHF from 10 embalmed hips (six female, four male; mean age 80.4 ± 8.7 years) were cut at three levels: the foveal attachment, mid-length and its base where it attaches to the transverse acetabular ligament. Sections were stained with haematoxylin and eosin to study general tissue architecture or with von Willebrand factor and neurofilament to identify blood vessels and nervous tissue, respectively. The proportion of the ligament's cross-sectional area occupied by blood vessels was expressed as a vascularity index (VI). Nerve endings within the ligament were identified and morphologically classified. Comparisons between the VI at the three levels, or between the tissue layers of the ligament, were made using 95% confidence intervals; statistical significance was set P < 0.05. The ligament tissue comprised three distinct layers: a synovial lining with cuboidal cells, a sub-synovial zone formed of loose connective tissue and the ligament proper composed of dense collagen bundles. Patent blood vessels and nerve fibres were present both in the sub-synovial zone and the ligament proper; Pacinian corpuscles and free nerve endings were found scattered only in the sub-synovial zone. The VI of the ligament proper at the fovea was significantly higher than its middle (P = 0.01) and basal levels (P = 0.04); it was also higher than that of the sub-synovial layer (P = 0.04). The LHF has three histologically distinct zones, and blood vessels and nerves are distributed both in the sub-synovial layer and ligament proper. Higher vascularity within the ligament proper at its foveal insertion suggests a possible nutritive role of the LHF to the adult head of femur. The presence of nerves and nerve receptors indicates the ligament is involved in the perception of pain and proprioception, thereby contributing to mechanical stability of the joint.