Osteochondral Defects of the Knee

This is a complex case requiring careful planning, realistic counseling, and potentially multi-stage reconstruction. The patient has three major concurrent pathologies contributing to her medial compartment overload and pain: (1) large 5cm² cartilage defect on MFC, (2) 6° varus malalignment, and (3) total medial meniscectomy (meniscal deficiency). The fundamental principle in cartilage restoration is that you cannot successfully treat the cartilage defect without addressing the concurrent pathology - the alignment and meniscal issues must be corrected or the cartilage procedure will fail. I would explain to her that while this is a challenging situation, she is NOT a candidate for knee replacement at age 35 - TKR in young patients (under 50) has poor long-term outcomes with high revision rates, and we should exhaust all joint preservation options first. Her case is complex but potentially salvageable with staged reconstruction. The problems: (1) The 5cm² cartilage defect is large and requires MACI (matrix-induced autologous chondrocyte implantation) or OCA (osteochondral allograft) - too large for microfracture or OAT. MACI is preferred first-line (two-stage, produces hyaline-like cartilage, good evidence for lesions 2-10cm²). (2) The 6° varus malalignment is severe and MUST be corrected with high tibial osteotomy (HTO) - cannot do cartilage procedure in malaligned knee as it will fail due to mechanical overload. Target is 3-5° valgus overcorrection (mechanical axis at 60-65% tibial width from medial, Fujisawa point) to unload the medial compartment and protect the cartilage repair. (3) The total medial meniscectomy has increased medial compartment contact stress by 50-100% (complete loss of load distribution), contributing to both cartilage defect progression and ongoing pain. She will need meniscal allograft transplantation (MAT) to restore meniscal function and protect the cartilage repair. My recommended surgical plan is a staged approach: Stage 1 - High Tibial Osteotomy (HTO): Perform opening or closing wedge HTO to correct the varus and achieve 3-5° valgus. This is the foundation - must correct alignment first before addressing cartilage and meniscus. Opening wedge HTO using medial approach, biplanar cut, achieve correction, fix with locking plate, bone graft to defect. Post-op: NWB 6 weeks, progressive weight-bearing, expect 3-4 months for bone healing. At 6 months post-HTO, confirm alignment correction with repeat full-length standing films and assess pain improvement. Stage 2 - Concurrent MAT + MACI (6-12 months after HTO): Once HTO healed and alignment confirmed corrected, proceed with combined meniscal allograft transplantation and cartilage restoration. MAT: Use fresh-frozen medial meniscal allograft, size-matched (within 5% using Pollard method or contralateral MRI), bone bridge technique for root fixation, suture periphery to capsule. MACI: For 5cm² lesion, this is ideal size. First arthroscopy to harvest chondrocytes (concurrent with MAT if single-stage, or separate if two-stage MACI). Then 3-4 weeks later (or concurrent if using stored chondrocytes), debride cartilage defect back to stable base, implant chondrocytes on collagen membrane, secure with fibrin glue/sutures. Mini-arthrotomy for both MAT and MACI implantation. Post-op for combined MAT + MACI: NWB or partial weight-bearing 6-8 weeks, ROM limited initially (0-90°) for 6 weeks to protect MAT and MACI, then progressive rehabilitation. Return to full activities 12-18 months. Alternative staging: Some surgeons prefer three-stage (HTO → MAT → MACI) to optimize biology, but I would favor two-stage (HTO, then MAT + MACI) to reduce total number of surgeries. Rationale for staging HTO first: (1) HTO creates biological milieu (bone marrow elements, growth factors from osteotomy healing) that may improve subsequent MAT and MACI incorporation, (2) Allows confirmation of alignment correction before committing to MAT + MACI, (3) Some patients (20-30%) get significant pain relief from HTO alone by unloading compartment - can reassess at 6 months if MAT + MACI still needed, (4) Doing all three procedures simultaneously is technically feasible but has high stiffness risk (15-20% vs 5-8% for single procedures) and very complex rehabilitation. Expected outcomes and counseling: This is joint preservation, not cure. With successful staged reconstruction (HTO + MAT + MACI), she has 60-70% chance of good-excellent pain relief and improved function. Goal is to delay knee replacement by 10-15 years (to age 45-50 when TKR is more appropriate). She will require 2-3 surgeries over 12-18 months, prolonged rehabilitation, significant time commitment, and multiple risks (infection, stiffness, graft failure for MAT or MACI, nonunion of HTO, neurovascular injury). Each procedure has 20-30% failure rate, compounded risk with multiple procedures. Alternative is to accept knee replacement now at age 35, which has poor long-term outcomes in young patients (50% revision rate by age 55-60) but is single surgery with predictable short-term relief. I would strongly recommend attempting joint preservation given her age, but she must understand the complexity, commitment, and uncertain outcomes. This is a marathon, not a sprint. If she proceeds, meticulous surgical technique, addressing all three pathologies, and compliant rehabilitation give her best chance. If she is not willing or able to commit to this process, conservative management and eventual TKR is the alternative.