Injectable autologous chondrocyte implantation in acetabular cartilage defects: 2-year minimum clinical and MRI results

Treatment of Hip Cartilage Defects in Athletes

Chondral defects in the athlete's hip are a relatively common occurrence, often presenting with debilitating pain and activity limitation. Preoperative identification of cartilage defects is challenging and there are many different modalities for treatment. Nonsurgical interventions, including activity modification, physical therapy, and injections, play a vital role, especially in less severe cases and as adjuncts to surgical intervention. Treating surgeons must be familiar with the cartilage restoration procedures available, including debridement, microfracture, and various implantation and transplantation options. Safe and effective management of cartilage defects is imperative to an athlete's return to sport. It is also imperative that surgeons are aware of all these various treatment options to determine what modality is best for their patients. This review serves to outline these options, cover the published literature, and provide general guidelines for surgeons when they encounter chondral defects in the office and the operating room.

Autologous Matrix-Induced Chondrogenesis for the Treatment of Hip Acetabular Chondral Lesions Demonstrates Improved Outcomes: A Systematic Review

PURPOSE

To systematically investigate the outcomes of patients who underwent autologous matrix-induced chondrogenesis (AMIC) during hip arthroscopy for the treatment of acetabular chondral lesions due to femoroacetabular impingement syndrome.

METHODS

PubMed and Cochrane were queried in June 2022 to conduct this systematic review using the following keywords: "femoroacetabular impingement," "arthroscopy," "microfracture," and "autologous matrix-induced chondrogenesis." Articles were included if they reported on patient-reported outcomes of AMIC during hip arthroscopy to treat chondral lesions of the hip. The review adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses criteria. Each study was queried for demographics, lesion classification, surgical treatment, patient-reported outcome scores, revision arthroscopy, and conversion to total hip arthroplasty (THA). A qualitative subanalysis was performed to compare patients undergoing AMIC to patients undergoing microfracture alone if included studies also assessed results of microfracture alone.

RESULTS

Four studies met inclusion criteria and assessed 209 hips undergoing AMIC. The included studies consisted of 99 male and 110 female patients. Mean postoperative follow-up ranged from 1 to 8 years, and mean patient age ranged from 34.3 to 45 years. Three of the 4 included studies reported the modified Harris Hip Score, and all 3 of these studies reported statistically significant improvement in the modified Harris Hip Score at final follow-up (P < .001) with mean preoperative values ranging from 44.5 to 62.8 and mean postoperative values ranging from 78.8 to 95.8. Two of the 4 studies compared patients treated with AMIC to microfracture alone. In these 2 studies, the AMIC groups reported 0 patients converting to THA while the microfracture-alone groups reported a highly variable rate of conversion to THA (2%-32.6%).

CONCLUSIONS

Patients who underwent hip arthroscopy and AMIC for the treatment of femoroacetabular impingement syndrome and acetabular chondral lesions demonstrated improved patient-reported outcomes and low rates of secondary surgeries at short-term follow-up. STUDY DESIGN: Level IV, systematic review of Level III and IV studies.

Minced Cartilage Implantation in Acetabular Cartilage Defects: Case Series with 2-Year Results

OBJECTIVE

The objective was to evaluate clinical outcome and safety of arthroscopic, autologous minced cartilage implantation for acetabular cartilage lesions observed during hip arthroscopy to treat femoroacetabular impingement syndrome (FAIS).

DESIGN

Eleven male patients, average age: 29.4 ± 5.4 years, average body mass index (BMI): 24.2 ± 2.2 kg/m2, scheduled for hip arthroscopy due to FAIS accompanied by an acetabular cartilage lesion were included in the case series. Cartilage tissue was harvested and minced from the loose cartilage flap at the chondrolabral lesion by arthroscopic shaver, augmented with autologous conditioned plasma, implanted into the defect, and fixated by autologous thrombin. Concomitant interventions were performed as indicated. The patients were evaluated preoperatively and at 24-month follow-up, using the International Hip Outcome Tool-12 (iHOT-12) and Visual Analog Scale (VAS) pain score and by magnetic resonance imaging (MRI) using the Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) grading scale at the 2-year follow-up.

RESULTS

The defect size was on average 3.5 cm2 (1.5-4.5 cm2). From preoperatively to 2 years postoperatively, the iHOT-12 significantly improved from 50.2 ± 18 to 86.5 ± 19 (P < 0.0001), and pain score decreased from 5.6 ± 1.8 to 1.0 ± 1.5 (P < 0.0001) on the Visual Analog Scale pain score. Regarding functional outcome and pain, 10 of the 11 patients and all patients reached the minimal clinically important difference (MCID), respectively. The postoperative average MOCART score was 87.2 (± 9.2). No adverse events or reoperations were observed.

CONCLUSIONS

Arthroscopic, autologous minced cartilage implantation for treating full-thickness acetabular cartilage lesions in FAIS shows statistically and clinically significant improvement at short-term follow-up.

Functionalized Electrospun Scaffold-Human-Muscle-Derived Stem Cell Construct Promotes In Vivo Neocartilage Formation

Polycaprolactone (PCL) is a non-cytotoxic, completely biodegradable biomaterial, ideal for cartilage tissue engineering. Despite drawbacks such as low hydrophilicity and lack of functional groups necessary for incorporating growth factors, it provides a proper environment for different cells, including stem cells. In our study, we aimed to improve properties of scaffolds for better cell adherence and cartilage regeneration. Thus, electrospun PCL–scaffolds were functionalized with ozone and loaded with TGF-β3. Together, human-muscle-derived stem cells (hMDSCs) were isolated and assessed for their phenotype and potential to differentiate into specific lineages. Then, hMDSCs were seeded on ozonated (O) and non-ozonated (“naïve” (NO)) scaffolds with or without protein and submitted for in vitro and in vivo experiments. In vitro studies showed that hMDSC and control cells (human chondrocyte) could be tracked for at least 14 days. We observed better proliferation of hMDSCs in O scaffolds compared to NO scaffolds from day 7 to day 28. Protein analysis revealed slightly higher expression of type II collagen (Coll2) on O scaffolds compared to NO on days 21 and 28. We detected more pronounced formation of glycosaminoglycans in the O scaffolds containing TGF-β3 and hMDSC compared to NO and scaffolds without TGF-β3 in in vivo animal experiments. Coll2-positive extracellular matrix was observed within O and NO scaffolds containing TGF-β3 and hMDSC for up to 8 weeks after implantation. These findings suggest that ozone-treated, TGF-β3-loaded scaffold with hMDSC is a promising tool in neocartilage formation.

An evidence-based update on the management of articular cartilage defects in the hip

Objective

Articular cartilage defects in the hip joint pose a significant surgical challenge and remain one of the most important determinants of success following arthroscopic intervention of the hip. The aim of this literature review was to report on the best available evidence on the various treatment options utilised for articular cartilage defects in the hip.

Material and methods

A comprehensive literature search was performed on PubMed from its inception to October 2021 using the following search strategy: ((hip) and (cartilage or chondral) and (repair or regeneration or restoration or implantation or chondroplasty or chondrogenic)). Two reviewers (KHSK, MG) independently reviewed titles and abstracts to identify articles for the final analysis. Articles were included if they were original research studies (randomised control trials, cohort studies, case-control studies, or comparative studies) on treatment of hip cartilage defects in humans reporting on a minimum of 5 patients. A total of 1172 articles were identified from the initial literature search. Following a thorough selection process, 35 articles were included in the final analysis to synthesise the evidence.

Results

Debridement, microfracture, autologous chondocyte implanatation (ACI) and matrix-induced ACI (MACI) are shown to have good short-to medium-term results. Injectable ACI and MACI have been developed to enable these procedures to be performed via arthroscopic surgery to reduce the post-operative morbidity associated with surgery with promising early results. Large cartilage defects which involved the sub-chondral bone may need the use of osteochondral grafts either autograft or allograft. Newer biological solutions have been developed to potentially deliver a single-stage procedure for hip cartilage injuries but longer-term results are still awaited.

Conclusion

Accurate identification of the extent of the injury helps stratify the defect and plan appropriate treatment. Several surgical techniques have shown good short to medium-term outcomes with ACI, AMIC, mosaicplasty and microfracture. Recent advances have enabled the use of injectable MACI and bioscaffolds which show promising results but in the shorter term. However, one needs to be mindful of the techniques which can be used in their surgical setting with the available resources. In order to thoroughly evaluate the benefits of the different surgical techniques for hip cartilage defects, large scale prospective multi-centre studies are necessary. Perhaps inclusion of such procedures in registries may also yield meaningful and pragmatic results.