Osteochondral defects (OCD) of the patella in skeletally immature patients are diagnostic and therapeutic challenges. These defects, often traumatic or idiopathic, can lead to progressive pain and early degeneration if untreated ^[1]. Traditional management includes microfracture, osteochondral autografts, and autologous chondrocyte implantation (ACI). While ACI has shown promising outcomes in patella-femoral lesions ^[2,3,4], its use in young patients is limited due to the two-staged nature, higher cost, and delayed recovery. Emerging single-stage, biologically augmented techniques utilizing minced autologous cartilage, platelet-rich plasma (PRP), and cartilage scaffolds offer an attractive alternative ^[5,6,7]. This case illustrates the application of such a technique (AutoCart, Arthrex) in an adolescent with an osteochondral patellar lesion.

A 14-year-old healthy, right-hand dominant male football player presented with a 9-month history of anterior knee pain on the right side. Pain was insidious in onset, worsened by stairs, squatting, and prolonged activity. No prior trauma or instability was reported. Mild effusion, positive patellar grind test, and crepitus were observed on physical examination, along with tenderness on the lateral facet of the patella. X-ray and computed tomography scan of the knee showed a smooth osteochondral defect in the lateral facet of the patella (Figs. 1 and 2). Magnetic resonance imaging (MRI) revealed a focal 14 × 12 mm osteochondral defect along the superior pole of the right patella on the lateral facet with >15 mm depth (Fig. 3). There were no signs of instability or ligamentous injury. Initial treatment consisted of physical therapy, activity modification, and NSAIDs for 3 months. Persistent symptoms prompted surgical management.

Surgical technique

Preparation

After a round of diagnostic arthroscopy (Fig. 4a) confirming the diagnosis and loose body removal, autologous minced cartilage, approximately 200 mg, was harvested arthroscopically from a non-weight-bearing area of the lateral femoral condyle and trochlea using an arthroscopic shaver. Simultaneously, nearly 60 mL of the patient’s blood was drawn and processed intraoperatively to isolate PRP.

Graft preparation

The cartilage was minced using a sterile shaver (GraftNet system) and mixed with micronized cartilage scaffold (BioCartilage) and autologous PRP to form a cohesive paste.

Application

The undersurface of the patella cannot be treated arthroscopically by this technique. Hence, an open procedure was carried out. A lateral parapatellar incision was made approximately 10 cm long and dissected by the lateral parapatellar approach. The patella was everted medially, and the large osteochondral defect was visualized (Fig. 4b).

• Cancellous bone graft obtained from the non-weight-bearing area of the lateral femoral condyle
• Defect site was debrided to stable cartilage margins, and bone was prepared using a curette to create a stable bed (Fig. 4c)
• Cancellous bone graft applied (Fig. 4d), followed by the biologic paste (Fig. 4e) to fill the defect and contour flush with the surrounding cartilage surface (Fig. 4f)
• Fibrin glue was applied to secure the construct (Fig. 5)
• The knee was held in extension post-application to ensure adhesion during the initial polymerization
• The knee was taken through a full range of movement to make the graft contoured with the surface of the patella.

The immediate post-operative period involved a hinged knee brace allowing flexion up to 30° flexion in the first 2 weeks, followed by progressive increase in range of motion (ROM) up to 90° in the 1^st month; progressive weight bearing was allowed as tolerated. Return to sports training at 4 months, full return to sports at 6 months.

The patient achieved pain-free walking at 2 months; almost full ROM and returned to football at 6 months (Fig. 6). IKDC pediatric increased from 52 (pre-operative) to 91 (12 months post-operative); KOOS-Child Sports subscore improved from 60 to 95. MRI findings (Fig. 7) at 6 months postoperatively showed a near-complete defect filling with well-defined cartilage of uniform signal intensity, nearly 3 mm thick, and likely to be hyaline. Minimal subchondral edema and cortical irregularity were noted, but without any unstable osteochondral fragments. No hypertrophy or delamination. No complications such as infection, arthrofibrosis, or donor site morbidity.

This case supports the viability of biologic, single-stage cartilage repair techniques in adolescents, particularly for patellar OCD. Compared to traditional matrix-induced autologous chondrocyte implantation or osteochondral autograft transfer system procedures ^[2,3], this approach avoids the need for multiple surgeries, preserves tissue, and leverages the high healing potential in young individuals ^[6]. A similar technique was described by Farr and Yao using BioCartilage and PRP for femoral condyle lesions ^[5], but data in adolescents and for patellar defects remain limited. Recent reports on AutoCart demonstrate promising mid-term results with simplified logistics and similar efficacy to staged ACI ^[7,8,9].

Limitations

Single-patient case study, lack of second-look arthroscopy or histology, and no long-term data beyond 18 months (Table 1 and 2).

Considerations

The regenerative environment in adolescents may enhance outcomes with biologic scaffolds. While long-term outcomes remain under investigation, early results support the feasibility of autologous minced cartilage repair for medium-sized patellar OCDs.

Single-stage autologous cartilage repair using minced cartilage, PRP, and scaffold represents a promising strategy for managing OCD in the adolescent patella. It provides functional improvement, radiographic healing, and high patient satisfaction with low morbidity.

Single-stage autologous minced cartilage repair combined with platelet-rich plasma scaffold is a promising and effective treatment for adolescent patellar osteochondral defects, offering functional improvement, radiographic healing, and high satisfaction with low morbidity, whereas avoiding the complexity and cost of traditional two-stage procedures.