Patellofemoral joint cartilage restoration with particulated juvenile allograft in patients under 21 years old

Charting a quarter-century of commercial cartilage regeneration products

Functional cartilage regeneration remains difficult to achieve despite decades of research. Dozens of commercial products have been proposed, with each targeting different facets of successful cartilage engineering, including mechanical properties, integration, lubrication and inflammation; however, there remains a lack of breakthroughs in meaningful clinical outcomes. Prior research categorized commercial products based on their components and elucidated challenges faced during the market approval process. This paper, for the first time, comprehensively reviews the properties of commercial products covering the last 25 years, including design trends in components, compatibility with minimally invasive surgery, indications for cartilage defects, long-term follow-up, as well as active sponsorship support of the International Cartilage Regeneration and Joint Preservation Society (ICRS). We aim to summarize the key factors for potentially successful commercial products and elucidate overarching trends in technology development in this field. Given that no revolutionary products have yielded significantly improved clinical results, emerging products compete with one another on user-friendliness and cost-efficiency. Other relevant characteristics include compatibility with minimally invasive surgery, extensiveness of required surgery (one-stage vs. two-stage), use of versatile artificial polymers and application of cells and biomaterials. Specific products continue to lead the market due to their cost-efficiency or indications for larger cartilage defects. However, they have been shown to result in no significant improvement upon clinical follow-up. Thus, there is a need for products that surpass current commercial products and show clinical effectiveness. Translation potential of this article: This review analyzes product components, compatibility with minimally invasive surgery, indication for cartilage defect areas, clinical performance as well as sponsorship for the World Conference of International Cartilage Regeneration & Joint Preservation Society, based on information about cartilage regeneration products from 1997 to 2023. It shines a light on future development of design and commercialization of cartilage products.

Particulated Juvenile Articular Cartilage Allograft Transplantation for Patellofemoral Defects Shows Favorable Return-to-Sport Rates and Patient-Reported Outcomes

PURPOSE

To report return-to-sport rates, postoperative patient-reported outcomes (PROs), complication rates, and reoperation rates of a cohort of patients undergoing particulated juvenile articular cartilage (PJAC) allograft transplantation for patellofemoral articular cartilage defects.

METHODS

We performed a single-institution retrospective review of all patients with patellofemoral articular cartilage defects who received PJAC allograft transplantation from 2014 to 2022. Baseline demographic characteristics and surgical data, including concomitant surgical procedures, were collected. Clinical outcomes recorded included return-to-sport rates, complications, reoperations, and the following PRO scores: Kujala knee score, Patient-Reported Outcomes Measurement Information System (PROMIS) Pain Interference score, and PROMIS Physical Function score.

RESULTS

Forty-one knees with a mean age of 23.4 ± 9.7 years and mean follow-up period of 30.3 months (range, 12-107 months) were included. The mean postoperative PROMIS Pain Interference, PROMIS Physical Function, and Kujala knee scores were 47.4 ± 7.7, 52.2 ± 10.8, and 81.7 ± 16.1, respectively, reflecting low residual anterior knee pain and a return to normal function. For patients playing organized sports at the high school and collegiate levels, the overall return-to-sport rate was 100% (17 of 17). During follow-up, complications developed in 12 knees (29.3%), the most common of which was anterior-based knee pain, and 6 knees (14.6%) required a total of 8 reoperations, which occurred from 6 to 32 months postoperatively.

CONCLUSIONS

The 100% return-to-sport rate and satisfactory PRO scores in our study suggest that PJAC allograft transplantation can effectively address patellofemoral cartilage defects in many patients. The complication and reoperation rates of 29.3% and 14.6%, respectively, are consistent with the challenging and heterogeneous etiology and treatment of patellofemoral articular defects.

LEVEL OF EVIDENCE

Level IV, case series.

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.

Outcomes of Particulated Juvenile Articular Cartilage and Association With Defect Fill in Patients With Full-Thickness Patellar Chondral Lesions

Background

Cartilage restoration procedures for patellar cartilage defects have produced inconsistent results, and optimal management remains controversial. Particulated juvenile articular cartilage (PJAC) allograft tissue is an increasingly utilized treatment option for chondral defects, with previous studies demonstrating favorable short-term outcomes for patellar chondral defects.

Purpose

To identify whether there is an association between defect fill on magnetic resonance imaging (MRI) with functional outcomes in patients with full-thickness patellar cartilage lesions treated with PJAC.

Study Design

Case series; Level of evidence, 4.

Methods

A retrospective review of prospectively collected data was conducted on patients treated with PJAC for a full-thickness symptomatic patellar cartilage lesion between March 2014 and August 2019. MRI was performed for all patients at 6, 12, and 24 months postoperatively. Patient-reported outcome measures (PROMs) were obtained preoperatively and at 1, 2, and >2 years postoperatively. Clinical outcome scores-including the International Knee Documentation Committee (IKDC) score, the Kujala, the Knee injury and Osteoarthritis Outcome Score-Physical Function Short Form (KOOS-PS), the Knee Injury and Osteoarthritis Outcome Score-Quality of Life (KOOS-QoL), and the Hospital for Special Surgery Pediatric Functional Activity Brief Scale (HSS Pedi-FABS)-were analyzed and evaluated for a relationship with tissue fill on MRI.

Results

A total of 70 knees in 65 patients (mean age, 26.6 ± 8.1 years) were identified, of which 68 knees (97%) underwent a concomitant patellar stabilization or offloading procedure. Significant improvements were observed on all postoperative PROM scores at the 1-, 2-, and >2-year follow-up except for the Pedi-FABS, which showed no significant difference from baseline. From baseline to the 2-year follow-up, the KOOS-QoL improved from 24.7 to 62.1, the IKDC improved from 41.1 to 73.5, the KOOS-PS improved from 35.6 to 15, and the Kujala improved from 52 to 86.3. Imaging demonstrated no difference in the rate of cartilage defect fill between the 3-month (66%), 6-month (72%), 1-year (74%), and ≥2-year (69%) follow-ups. No association was observed between PROM scores and the percent fill of cartilage defect on MRI at the 1- and 2-year follow-up.

Conclusion

PROM scores were significantly improved at the 2-year follow-up in patients who underwent PJAC for full-thickness patellar cartilage defects. On MRI, a cartilage defect fill of >66% was achieved by 3 months in most patients. In our sample, PROM scores were not significantly associated with the defect fill percentage at the short-term follow-up.

Regeneration of joint surface defects by transplantation of allogeneic cartilage: application of iPS cell-derived cartilage and immunogenicity

BACKGROUND

Because of its poor intrinsic repair capacity, articular cartilage seldom heals when damaged.

MAIN BODY

Regenerative treatment is expected for the treatment of articular cartilage damage, and allogeneic chondrocytes or cartilage have an advantage over autologous chondrocytes, which are limited in number. However, the presence or absence of an immune response has not been analyzed and remains controversial. Allogeneic-induced pluripotent stem cell (iPSC)-derived cartilage, a new resource for cartilage regeneration, reportedly survived and integrated with native cartilage after transplantation into chondral defects in knee joints without immune rejection in a recent primate model. Here, we review and discuss the immunogenicity of chondrocytes and the efficacy of allogeneic cartilage transplantation, including iPSC-derived cartilage.

SHORT CONCLUSION

Allogeneic iPSC-derived cartilage transplantation, a new therapeutic option, could be a good indication for chondral defects, and the development of translational medical technology for articular cartilage damage is expected.

Engraftment of allogeneic iPS cell-derived cartilage organoid in a primate model of articular cartilage defect

Induced pluripotent stem cells (iPSCs) are a promising resource for allogeneic cartilage transplantation to treat articular cartilage defects that do not heal spontaneously and often progress to debilitating conditions, such as osteoarthritis. However, to the best of our knowledge, allogeneic cartilage transplantation into primate models has never been assessed. Here, we show that allogeneic iPSC-derived cartilage organoids survive and integrate as well as are remodeled as articular cartilage in a primate model of chondral defects in the knee joints. Histological analysis revealed that allogeneic iPSC-derived cartilage organoids in chondral defects elicited no immune reaction and directly contributed to tissue repair for at least four months. iPSC-derived cartilage organoids integrated with the host native articular cartilage and prevented degeneration of the surrounding cartilage. Single-cell RNA-sequence analysis indicated that iPSC-derived cartilage organoids differentiated after transplantation, acquiring expression of PRG4 crucial for joint lubrication. Pathway analysis suggested the involvement of SIK3 inactivation. Our study outcomes suggest that allogeneic transplantation of iPSC-derived cartilage organoids may be clinically applicable for the treatment of patients with chondral defects of the articular cartilage; however further assessment of functional recovery long term after load bearing injuries is required.