This prospective study analyses the histological results of autologous chondrocyte transplantation in patients with articular cartilage defects of the knee joint. Chondrocytes from a non-weight bearing area of the knee were harvested and then cultured in vitro.

Re-implantation involved injection of the chondrocytes into the defect, which was then sealed with a collagen membrane. One year post-op, patients were evaluated by clinical, arthroscopic and histological assessment. A biopsy of the transplanted region was examined by staining with Erlich’s H& E and Safranin 0, polarised light microscopy and by analysis with S100 and immunohistochemistry. Hyaline cartilage content was further assessed by examination of Type IIa & lIb collagen mRNA expression using in-situ hybridisation.

The median age was 31 years. 63 knees were treated. Solitary lesions were treated in 61 knees with two defects being treated in three knees (66 defects in total). The defects were located on the medial femoral condyle in 39 cases, lateral femoral condyle in 14, trochlea in 2 and patella in 11. The defect size ranged from 1–7 cm2 (mean area 3cm2 ). 40 patients had at least one-year follow-up. Using the Brittberg Rating, 11 had excellent results, with 15 good, 10 fair and 4 poor. The mean Lysholm and Gillquist scores improved from 44 pre-op to 77 one-year post-op. Biopsy at one year conftrmed the presence of hyaline cartilage in 22 out of 32 cases (69%). In-situ hybridisation confirmed the presence of Collagen type II in the deep zones of the biopsy with a fibrocartilaginous appearance superficially.

Conclusion: This technique can provide an effective treatment for cartilage defects. The histological results are encouraging and chondrocyte transplantation may be the only procedure to allow regeneration of hyaline like articular cartilage.

Aim: This prospective study analyses the histological results of autologous chondrocyte transplantation in patients with articular cartilage defects of the knee joint.

Methods: This is a prospective, single centre, single surgeon study. Consecutive patients undergoing autologous chondrocyte transplantation were studied. Chondrocytes from a non-weight bearing area of the knee were harvested and then cultured in vitro. Re-implantation involved injection of the chondrocytes into the defect, which was then sealed with a collagen membrane. One year post-op, patients were evaluated by clinical, arthroscopic and histological assessment. A biopsy of the transplanted region was examined by staining with Erlich’s H& E and Safranin O, polarised light microscopy and by analysis with S100 and immunohistochemistry. Hyaline cartilage content was further assessed by examination of Type IIa & IIb collagen mRNA expression using in-situ hybridisation.

Results: The median age was 31 years. 63 knees were treated. Solitary lesions were treated in 61 knees with two defects being treated in three knees (66 defects in total). The defects were located on the medial femoral condyle in 39 cases, lateral femoral condyle in 14, trochlea in 2 and patella in 11. The defect size ranged from 1–7 cm2 (mean area 3cm2). 40 patients had at least two-year follow-up. Using the Brittberg Rating, 11 had excellent results, with 15 good, 10 fair and 4 poor. The mean Lysholm and Gillquist scores improved from 44 pre-op to 77 two-years post-op. Biopsy at one year confirmed the presence of hyaline cartilage in 22 out of 32 cases (69%). In-situ hybridisation confirmed the presence of Collagen type II in the deep zones of the biopsy with a fibrocartilaginous appearance superficially.

Conclusion This technique can provide an effective treatment for cartilage defects. The histological results are encouraging. Chondrocyte transplantation appears to regenerate tissue with the features of normal hyaline cartilage.

Aims: Damage to articular hyaline cartilage may predispose to earlyonset osteoarthritis. Hyaline cartilage has not been shown to spontaneously regenerate and previous methods of stimulating repair have often yielded þbrocartilage. Autologous chondrocyte implantation (ACI) offers the potential for hyaline cartilage repair. Methods: A prospective study of 31 patients undergoing ACI using the chondrogide membrane. Patients were assessed clinically using validated knee scores pre-operatively and post-operatively at yearly intervals. Arthroscopy was carried out at one year post implantation and a biopsy of the transplanted area was sent for histological examination. Results: 32 knees (including 2 bilateral) were reviewed clinically at one year, and 15 were reviewed at 2 years. 33 defects (including 2 defects in one knee) were assessed arthroscopically at one year. Only one repair showed hypertrophy at one-year arthroscopy, and 8 had poor integration. Hyaline-like cartilage was demonstrated in 70% of the repairs. Patients showed improvement in the Verbal Numerical Pain scores and in the Lysholm and Gillquist score. Conclusions: In our series, the use of chondrogide membrane shows a low incidence of hypertrophy when compared to periosteum. Improvement in knee scores was statistically signiþcant at one and two years.

We have performed a prospective, single-surgeon study analysing the histological results of autologous chondrocyte implantation.

Fourteen patients underwent autologous chondrocyte implantation of the knee and were evaluated at one year by clinical assessment and arthroscopy. Standard staining was used to examine the sections. In addition, in situ hybridisation was used to establish type-IIa and type-IIb collagen mRNA expression and immunolocalisation techniques demonstrated the positions of type-II and type-X collagen.

Eight patients regenerated hyaline cartilage and also contained type-X collagen in the deepest layers and type-II collagen in the deep layers. Three demonstrated fibrocartilage and had type-II collagen in the deep layers. In situ hybridisation revealed that all 14 samples had the potential to express both type-IIa and type-IIb collagen.

We have shown that one year after the initial implantation chondrocytes are capable of producing type-II collagen and that they continue to proliferate and mature.

Background: The purpose of this prospective study is to analyse the histological results of the treatment of deep chondral defects with autologous chondrocyte transplantation in patients with articular cartilage defects of the knee joint.

Methods: Patients with articular cartilage defects of the knee joint were recruited prospectively and underwent autologous chondrocyte transplantation. Chondrocytes from a non-weight bearing area of the knee were harvested, isolated and cultured in vitro. Subsequent reimplantation involved injection of the chondrocytes into the defect which was then sealed with a porcine IIIII collagen membrane. Postoperatively, patients were evaluated at one year by clinical assessment, arthroscopy and histological examination. The presence of hyaline cartilage in the transplanted region was determined by staining with Erlich’s H & E, Safranin 0 and polarised light microscopy and by imimmohistochemical analysis with S100. Confirmation of the presence of hyaline cartilage was further assessed by examination of Type 11 collagen messenger RNA expression using PCR.

Results: Thirty four patients were recruited between July 1998 and November 2001, with a median age of 31 years (range 15–51 years). Of the 34 patients treated, 17 had right-sided lesions, 15 had left-sided lesions and two patients had bilateral lesions. Solitary lesions were treated in 36 knees with two defects being treated in one knee (37 defects in total). The defects were located on the medial femoral condyle in 22 cases, the lateral femoral condyle in eight, the trochlea in two and the patella in five cases. The defect size ranged from 1–7 cm2 (mean area 2.88cm2). The follow-up of the patients ranged from 1–39 months (mean 19 months). Twenty five patients had at least one-year follow-up. Of these patients, using the BritIberg Rating, six patients had excellent results, with 11 good, six fair and two poor. The mean Lysholin and GilIquist scores improved from 44.7 pre-op to 76.2 one-year post-op and the mean Verbal Numerical Pain Scores improved from 7.1 to 1.1. Arthroscopy revealed that the transplants were level with the surrounding surface in most cases. Biopsy at one year confirmed the presence of hyaline cartilage in 13 out of 19 cases (70%).

Conclusion: Although long-term follow-up is currently unavailable, autologous chondrocyte transplantation can provide, with careful patient selection and meticulous surgical technique, an effective treatment for cartilage defects of the knee. The histological results are extremely encouraging and chondrocyte transplantation may be the only procedure to allow regeneration of hyaline cartilage.

Introduction: Articular cartilage defects within the knee joint have poor capacity for repair. The purpose of this study is to analyse the short-term clinical and histological results of the treatment of deep chondral defects with autologous chondrocyte transplantation.

Methods: This is a prospective study involving twenty-two consecutive patients receiving autologous chondrocyte transplantation. Chondrocytes from a non weight bearing area of the knee are harvested, then isolated and cultured in vitro. Re-implantation involves injection of the chondrocytes into the defect which is then sealed with a porcine I/III collagen membrane. Evaluation consists of clinical assessment, arthroscopy and histological examination. Histological evaluation consists of examination of a biopsy of the transplanted area one-year post-op. Staining techniques include the use of Erlich’s H & E, Safranin O and S100. Using polarised light, the absence of the fibrillar nature of fibrocartilage confirms the presence of hyaline cartilage. Further confirmation can be gained by the examination of messenger RNA content, confirming the presence of type II collagen.

Results: The patients were treated between July 1998 and December 2000. The age range of the patients was 15–51 years (mean age 31 years). Of the 22 patients treated, 13 had right-sided lesions, 11 had left-sided lesions with two patients receiving bilateral procedures. Solitary lesions were treated in 23 knees with two defects being treated in one knee (25 defects in total). The defects were located on the medial femoral condyle in 17 cases, the lateral femoral condyle in five, the trochlea in two and the patella in one case. The defect size ranged from 1–5.4cm2 (mean area 2.65cm2). The follow-up of the patients ranges from 3-30 months (mean 16 months). Thirteen patients have at least one-year follow-up. Of these patients, using the Brittberg Rating, two patients have excellent results, with six good, four fair and one poor. The mean Lysholm and Gillquist scores improved from 50 pre-op to 72 one-year post-op and the mean Verbal Numerical Pain Scores improved from 7.2 to 2.6. Arthroscopy revealed that the transplants were level with the surrounding surface in most cases. Biopsy at one year confirmed the presence of hyaline cartilage in 10 out of 13 cases.

Conclusion: Although the results are short-term, autologous chondrocyte transplantation can provide, with careful patient selection and meticulous surgical technique, an effective treatment for cartilage defects of the knee. The histological results are extremely encouraging and chondrocyte transplantation may be the only procedure to allow regeneration of hyaline cartilage.