Knee salvage procedures: The indications, techniques and outcomes of large osteochondral allografts

Abstract

The overall incidence of osteochondral defect in the general population is estimated to be 15 to 30 per 100000 people. These lesions can become symptomatic causing pain, swelling and decreased function of the knee, and may eventually progress to osteoarthritis. In the young and active population, partial or total knee arthroplasty (TKA) is rarely the treatment of choice due to risk of early failure. Osteochondral allograft transplantation has been demonstrated to be a safe and effective treatment of large osteochondral and chondral defects of the knee in appropriately selected patients. The treatment reduces pain, improves function and is a viable limb salvage procedure for patients, especially young and active patients for whom TKA is not recommended. Either large dowels generated with commercially available equipment or free hand shell allografts can be implanted in more posterior lesions. Current recommendations for fresh allografts stored at 4C advise implantation within 21-28 d of procurement for optimum chondrocyte viability, following screening and testing protocols. Higher rates of successful allograft transplantation are observed in younger patients, unipolar lesions, normal or corrected malalignment, and defects that are treated within 12 mo of symptom onset. Patients with bipolar lesions, uncorrectable malalignment, advanced osteoarthritis, and those over 40 tend to have less favourable outcomes. Core tip:Osteochondral allograft transplantation has been demonstrated to be a safe and effective treatment of large osteochondral and chondral defects of the knee in appropriately selected patients. The treatment reduces pain, improves function and is a viable limb salvage procedure for patients, especially young and active patients for whom total knee arthroplasty is not recommended. Current recommendations for fresh allografts stored at 4C advise implantation within 21-28 d of procurement for optimum chondrocyte viability, following screening and testing protocols. Higher rates of successful allograft transplantation are observed in younger patients, unipolar lesions, normal or corrected malalignment, and defects that are treated within 12 mo of symptom onset.

Large Osteochondral Allografts of the Knee: Surgical Technique and Indications

“…Absolute contraindications include early and multicompartmental osteoarthritis (OA), inflammatory arthropathies, and altered bone metabolism (i.e., smokers, alcohol abusers, and chronic steroid users). 17 …”

“… 39 40 41 Ligamentous instability, malalignment, and the absence of >50% of the ipsilateral meniscus are relative contraindications that may require concomitant surgical procedures. 17 …”

“…Allograft subsidence may be a milder complication causing persistent slight pain due to a low-grade chronic inflammatory reaction to the graft. 17 Immunological reactions could be the main cause of failure in large OCA with associated soft tissue transplant, as in bipolar OCA of the knee. Progressive OA and instability make these specific knee OCAs unsuitable for the treatment of posttraumatic end-stage OA.…”

“…Osteochondral allograft (OCA) represents a solution for the treatment of large and deep osteochondral lesions, in both primary and revision procedures, with different advantages: possibility of covering virtually all sizes of defects, presence of subchondral bone, possibility of restoring complex surfaces and uncontained lesions, and absence of donor-site morbidity. 17 18 19 20 21 22 23 24 25 26 27 28 The main limitations of OCA are costs and graft availability. 29…”

Fresh Osteochondral Patellar Allograft Resurfacing

“…In addition, osteochondral integration is accomplished because of a creeping substitution phenomenon only in the first 8 to 12 mm layer of bone tissue. 14 , 15

Fig 1 Right knee. A standard short medial parapatellar approach is preferably used.

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