Introduction and Aims: To determine the efficacy of autologous chondrocyte implantation (ACI) in treating focal chondral defects of the knee, we reviewed the two-year treatment outcome of ACI in 53 patients through clinical evaluation, MRI, second-look arthroscopy and core biopsies obtained.

Method: From November 2000 to December 2003, 54 consecutive knees with 72 focal chondral defects (grade III or IV by modified Outerbridge) were treated with ACI using the Peterson periosteal patch technique. In this method, an initial arthroscopy was carried out to confirm the suitability for repair and when appropriate, cells were harvested either from the margins of the lesion, the intercondylar notch or both. The harvested cells were proliferated in vitro. Three to four weeks later, the cells were implanted in the defect with a medial or lateral parapatellar arthrotomy approach. A standardised post-operative rehabilitation protocol was carried out depending on the site of the lesion or lesions.

Results: Improvement in mean subjective score from pre-operative (37.6) to 12 months (56.4) and 24 (60.1) months post-ACI were observed. Knee function levels also improved (86% ICRS III/IV to 66.6% I/II) from pre-operative period to 24 months post-implantation. Objective IKDC score of A or B were observed in 88% pre-operatively. This decreased to 67.9% at three months before improving to 92.5% at 12 months and 94.4% at 24 months post-implantation. Transient deterioration in all these clinical scores was observed at three months before progressive improvement became evident. MRI studies demonstrated 75.3% with at least 50% defect fill, 46.3% with near normal signal, 68.1% with mild/no effusion and also 66.7% with mild/no underlying bone marrow edema at three months. These values improved to 94.2%, 86.9%, 91.3% and 88.4% respectively at 12 months. At 24 months, further improvement to 97%, 97%, 95.6% and 92.6% respectively were observed. Second-look arthroscopy carried out in 22 knees (32 lesions) demonstrated all grafts to be normal / nearly normal based on the International Cartilage Repair Society (ICRS) visual repair assessment while core biopsies from 20 lesions demonstrated 13 (65%) grafts to have hyaline / hyaline-like tissue.

Conclusion: Improvement in clinical and MRI findings obtained from second-look arthroscopy and core biopsies evaluated indicate that, at 24 months post-ACI, the resurfaced focal chondral defects of the knee remained intact and continued to function well.

Introduction Talar dome lesions are a common accompaniment of ankle injury resulting in ongoing symptoms and functional disability with current management resulting in fibrocartilaginous repair and failure to reconstitute the articular surface. In this study, the application of autologous chondrocyte implantation (ACI) for talar dome lesions was evaluated.

Methods Between August 2001 and February 2003, eight patients with osteochondral lesions of the talus were treated with ACI. All patients underwent initial arthroscopy to harvest healthy chondrocytes for cultivation. Cells were re-implanted after three to four weeks, with a medial or lateral malleolar osteotomy using a periosteal patch harvested from the distal tibia. Post-operatively, early ankle motion was allowed but non-weight bearing advised until union of osteotomy. Clinical assessment was pre-operatively and at three, six, nine, and 12 months post-operatively. Second-look arthroscopy with biopsy for histological examination was performed at removal of internal fixation. Four males and four females with a mean age of 40 years (range 22 to 59) are presented. Pre and postoperative clinical evaluation was done using the American Orthopaedic Foot and Ankle Society Hindfoot Score.

Results The mean pre-operative score was 58.4 (range 26 to 97); at three months, it was 62 (range 32 to 84); at six months 70.6 (range 66 to 92); at nine months 79 (range 66 to 92) and at 12 months 81.5 (range 79 to 84). MRI done in four patients at three months post-ACI showed good fill in three and slight over fill in one. Minimal subchondral edema was evident in one patient. Two patients with MRI 12 months post-ACI also revealed good fill with residual bone marrow oedema. Second-look arthroscopy and biopsy at implant removal in five patients were done at a mean of six months (range 2.5 to 9) post-ACI. Arthroscopy showed the transplants were level with the surrounding tissue. Four patients had biopsies showing hyaline-like cartilage which has all the properties of normal hyaline except for the increased cell density while one biopsy revealed fibro-hyaline tissue. Marginal biopsies taken demonstrated integration of neo-cartilage to adjacent cartilage.

Conclusions This study although with a limited sample, demonstrates the viability of ACI as treatment for osteochondral defects of the talus. Short-term results demonstrated clinical improvement from pre-operative to post-operative condition compatible with findings at second-look arthroscopy and histologic examination.

Introduction: Disc degeneration is consistent with advancing age and in many cases is associated with back pain and restricted mobility. The traditional surgical treatment for chronic back pain has been spinal fusion to immobilize the painful level. Long-term studies, however, suggest that fusion actually promotes degeneration at adjacent levels. One of the hallmarks of disc degeneration is aggregation of chondrocytes in the nucleus of chondrones, and more recently apoptosis has been implicated as a factor controlling the longevity of the cells. Recent research suggests that it may be possible to restore normal function to degenerate discs by introducing a fresh population of cells. This study investigated the potential for autologous costal chondrocyte implantation to prevent lumbar disc degeneration after annular injury in the sheep.

Methods: the lumbar spines of eight adult sheep were exposed. In four animals, full thickness annular incisions were made in three alternate discs. No annular incisions were made in the other four sheep. A minimum of 500 mg of cartilaginous tissue was harvested from the twelfth rib of all animals. Tissue was cultured in vitro and the chondrocytes were labelled with a fluorescent marker for retrospective identification. After six weeks the chondrocytes were injected into the lower two alternate discs of all animals, leaving the uppermost discs and those untouched as internal controls. The animals were killed at intervals from three to twenty-four weeks and MRI, plain x-ray, histology and immunocytochemistry were evaluated.

Results: MRI at twelve and twenty-four weeks showed apparent preservation of all incised discs that had been transplanted with autologous chondrocytes. Histology revealed clusters of viable chondrocytes of normal appearance within the nucleus. These cells stained positive for the fluorescent label. The same cells and the surrounding matrix were also positive for collagen type II. Serial X-ray measurements suggested that progressive disc degeneration was arrested in the discs that received autologous costal chondrocytes.

Discussion: This pilot study showed evidence that cultured autologous costal chondrocytes remained viable and produced extracellular matrix following transplantation into normal and degenerate discs. In contrast to other studies that have used mesenchymal stem cells or chondrocytes harvested directly from discs, this study demonstrated success with cells from a source other than the disc. Costal cartilage is a convenient source of cells for transplantation and this technique warrants further investigation as a potential treatment for degenerative disc disease.

INTRODUCTION: The development of laboratory techniques in the last ten years has enabled the successful harvest, in vitro selection, culture and transplant of chondrocytes. The study proposes that transplantation of autologous chondrocytes prevents degeneration of the intervertebral disc following outer annular injury in an ovine model.

METHODS: Eight sheep were anaesthetised and five contiguous lumbar discs were exposed via a left-sided posterolateral approach. Four of the animals were given full thickness annular incisions in three alternate discs. No annular incisions were made in the other four sheep. Costal cartilage was harvested from the left twelfth rib of all animals. Tissue was cultured and the chondrocytes were labelled in vitro with CFSE for verification following transplantation. Six weeks later autologous cultured chondrocytes were injected into the lower two alternate discs of all animals, leaving the uppermost discs and those untouched in between as internal controls. Animals were sacrificed after three, six, twelve and twenty-four weeks. Results were based on X-rays, histological, and immunocytochemical assessments.

RESULTS: Preliminary histological results up to three months showed viability of cultured chondrocytes and matrix production post transplantation. Serial X-rays suggested that progressive disc degeneration was arrested in the treated discs.

DISCUSSION: In this pilot study we have shown that cultured autologous chondrocytes can remain viable long term in vivo. These preliminary results suggest that these transplanted chondrocytes have the ability to retard and possibly prevent disc degeneration following annular incision. Previous similar studies have reported the use of chondrocytes cultured from disc, whilst this study showed that chondrocytes from a source foreign to the disc can exert positive effects. The encouraging result from this pilot study needs to be further validated to realise its potential as a treatment for degenerative disc disease.

Introduction: Human autologous chondrocyte transfer requires a small biopsy of articular cartilage (300–500 mg wet weight) obtained by arthroscopy from the patient’s knee joint. Chondrocytes are isolated and seeded at low density in monolayer culture to increase cell number. A common problem with this technique is that chondrocytes lose their phenotype by reverting to a fibroblast phenotype and synthesize a different matrix. Collagen type II and aggrecans are unique to hyaline cartilage-matrix. They form an extensive three-dimensional network of extracellular matrix in which other cell adhesion and growth factor molecules are integrated. It has been shown that a three dimension environment coupled with growth factors are important for the maintenance of the chondrocyte phenotype. Although cells cultured in alginate beads maintain their phenotype they do not proliferate well.

Aim of study: To develop and optimise a bovine chondrocyte culture system as a model for optimising human chondrocyte proliferation without dedifferentiation and their future transplantation. The optimum cell density determined for bovine chondrocyte cultures was used for human chondrocyte cultures. Cell proliferation and matrix synthesis of cultured human chondrocytes from normal as well as damaged knee joint articular cartilage obtained from debridement arthroscopy was investigated.

Methods: Bovine chondrocytes were seeded in collagen type I gels at various densities ranging from 104 to 106 cells/ml to obtain the minimal cell density required in a collagen gel culture system in which chondrocytes can proliferate and yet retain their unique phenotype. The media were supplemented with either bovine foetal calf serum (FCS) or a combination of three growth factors (3GFs), TGF-b1 + IGF-I + b-FGF. Cells and matrix were analysed on day 7, 14, and 21 of culture. Cell proliferation was determined by the trypan blue exclusion test. Cell morphology and matrix present were evaluated with both light and electron microscopy. A collagen type II specific antibody coupled with FITC conjugate was used to detect type II collagen neo-deposit in relation to the seeded type I collagen gels. The newly synthesised matrix was monitored after labelling cells with 35S-sulphate and 3H-proline. The collagen type was determined by SDS-PAGE Fluorography. Analysis of morphology and matrix synthesis was performed as

Results: Cell proliferation: Bovine chondrocytes cultured in collagen type I gels at low density proliferated up to 40 fold after 3 weeks while high density cultures proliferated only about 3 fold. There was no significant difference in cell numbers at day 21 in cultures supplemented with FCS or 3GFs. Therefore all human chondrocyte cultures were cultured at low density. Preliminary results from human chondrocyte cultures were obtained from 4 patients aged 59+19. After 4 weeks, human chondrocytes cultured at low density supplemented with FCS proliferated up to 10 fold in monolayer culture and up to 4 fold in collagen type I gels. Morphology: At all cell densities, the majority of bovine chondrocytes in the gels remained rounded while some cells near the surface of the gels were elongated. Human chondrocytes cultured at low density also demonstrated similar morphology. Matrix synthesis: For bovine chondrocyte culture, after 2 weeks in culture more than 70% of 35S-sulphate and 3H-proline incorporated matrix

Conclusions: This study has shown that bovine chondrocytes cultured at low density in collagen type I gels proliferated better than at high density and retained their phenotype. This low-density bovine chondrocyte culture model is applicable to human chondrocyte culture in vitro. Preliminary results shows that human chondrocytes obtained from patients aged 39–72 can proliferate both in gels and monolayer. Age of chondrocytes and growth factors may affect the growth of cells. This model system needs to be further investigated in normal human chondrocytes.