The Biological Response following Autogenous Bone Grafting for Large-Volume Defects of the Knee

Abstract

Objective:This report focuses on the biological events occurring at various intervals following autogenous bone grafting of large-volume defects of the knee joint’s femoral condyle secondary to osteochondritis dissecans (OCD) or osteonecrosis (ON). It was hypothesized that the autogenous bone graft would integrate and the portion exposed to the articular surface would form fibrocartilage, which would endure for years.Methods:Between September 29, 1987 and August 8, 1994, there were 51 patients treated with autogenous bone grafting for large-volume osteochondral defects. Twenty-five of the 51 patients were available for long-term follow-up up to 21 years. Patient follow-up was accomplished by clinical opportunity and intentional research. Videotapes were available on all index surgeries for review and comparison. All had preoperative and postoperative plain film radiographs. Long-term follow-up included MRI up to 21 years. Second-look arthroscopy and biopsy were obtained on 14 patients between 8 weeks and 20 years.Results:Radiological assessment showed the autogenous bone grafts integrated with the host bone. The grafts retained the physical geometry of the original placement. MRI showed soft tissue covering the grafts in all cases at long-term follow-up. Interval biopsy showed the surface covered with fibrous tissue at 8 weeks and subsequently converted to fibrocartilage with hyaline cartilage at 20 years.Conclusion:Autogenous bone grafting provides a matrix for large osteochondral defects that integrates with the host bone and results in a surface repair of fibrocartilage and hyaline cartilage that can endure for up to 20 years.

The Long-Term Clinical Outcomes Following Autogenous Bone Grafting for Large-Volume Defects of the Knee

“…Two patients in the ON group were not of spontaneous origin, but iatrogenic. 1 One patient’s ON was due to a YAG laser used at time of the previous arthroscopy, and the other patient’s ON was due to leukemia chemotherapy treatment including cortisone.…”

“…This is the companion report to a previously published study on the biological response. 1 At the time this study was initiated, the medical literature held no prospect for sustainable cartilage repair while the biological fate of various approaches to cartilage repair remain controversial. 2 - 8 The surgical treatment in the early 1980s for large-volume femoral condyle defects was total knee arthroplasty or a cadaver osteochondral allograft.…”

“… 18 Biopsies of the previously exposed grafted surfaces of these cases at 8 weeks showed histomorphology similar to that observed after abrasion arthroplasty. 1 It had been observed that fibrocartilage formed over surgically abraded exposed bone in the arthritic knee survived for 2 years. 19 Animal studies supported a similar biological fate of autogenous bone grafting to large osteochondral defects.…”

“…It was hypothesized that the autogenous bone graft would integrate and the articular surface would form fibrocartilage that would endure and provide a clinical benefit. 1 …”

What I Have Seen and Learned Since Looking Through an Arthroscope: 43 Years and Counting

“…To answer this question I refer you to a report on a long-term followup series of the most unlikely candidates for articular cartilage healing. 31 These were patients who had large 3-dimensional osteochondral defects of the medial femoral condyle. They underwent autogenous bone grafting of the defects.…”