Paul E Harrison

Autologous chondrocyte implantation for cartilage repair: monitoring its success by magnetic resonance imaging and histology

Autologous chondrocyte implantation is being used increasingly for the treatment of cartilage defects. In spite of this, there has been a paucity of objective, standardised assessment of the outcome and quality of repair tissue formed. We have investigated patients treated with autologous chondrocyte implantation (ACI), some in conjunction with mosaicplasty, and developed objective, semiquantitative scoring schemes to monitor the repair tissue using MRI and histology. Results indicate repair tissue to be on average 2.5 mm thick. It was of varying morphology ranging from predominantly hyaline in 22% of biopsy specimens, mixed in 48%, through to predominantly fibrocartilage, in 30%, apparently improving with increasing time postgraft. Repair tissue was well integrated with the host tissue in all aspects viewed. MRI scans provide a useful assessment of properties of the whole graft area and adjacent tissue and is a noninvasive technique for long-term follow-up. It correlated with histology (P = 0.02) in patients treated with ACI alone.

Autologous chondrocyte implantation with bone grafting for osteochondral defect due to posttraumatic osteonecrosis of the hip- : a case report

Copyright© Taylor & Francis 2006. ISSN 1745–3674. Printed in Sweden – all rights reserved. DOI 10.1080/17453670610046208 A 31-year-old man sustained a severe fracture dislocation of the left hip as a result of a road traffic accident in 2001. There was a subcapital fracture of the femoral head with complete separation of the head from the femoral neck, and posterior wall fracture of the acetabulum (Figure 1). The initial management was open reduction and internal fixation, and the immediate postoperative radiograph showed the screws to be in a satisfactory position within the femoral head. After 1 year, the patient was walking with one crutch and the range of movement of the left hip was restricted due to severe pain. At this time, his hip score (HS) was 52 of a possible 100 (Harris 1969). Radiography demonstrated a united femoral fracture, but the fixation screws had penetrated the hip joint due to collapse of the osteonecrotic femoral head, and there was narrowing of the joint space (Figure 2). Taking the young age of the patient into account, we decided to proceed with autologous chondrocyte implantation (ACI). The first stage was performed 21 months after the original injury. During an arthroscopy of the ipsilateral knee, 240 mg of macroscopically normal full depth cartilage was harvested from the low load area of the medial trochlea. The tissue was transported to a dedicated clinical cell culture laboratory for isolation and expansion of the chondrocytes as previously

The in vitro growth of human chondrocytes.

Autologous chondrocyte implantation (ACI) for the treatment of articular cartilage defects has been described by other workers, however, relatively few details of the in vitro growth of the cells have been published. Here we describe the release of cells from adult human articular cartilage and their growth characteristics in vitro.Cultures were successfully established from 29 of 30 biopsies taken from patients aged 20–72 year. No significant relationship was found between donor age and initial cell yield following cartilage digest, however, the time to primary confluence increased in direct proportion to age. Thereafter the kinetics of cell proliferation was independent of donor age.The proportion of apoptotic or necrotic cells in the cartilage digest was low and increased with time in culture only in those cells which remained non-adherent. Conversely, entry into cell cycle was restricted to those cells which had become adherent.These results illustrate that previously reported techniques for isolating and culturing chondrocytes are reproducible, that adherent chondrocytes have considerable proliferative potential, and that concern about cell growth and viability need not, in itself, limit the clinical application of ACI to younger patients.

Midterm to long-term longitudinal outcome of autologous chondrocyte implantation in the knee joint:a multilevel analysis

Background Autologous chondrocyte implantation is a cell therapeutic approach for the treatment of chondral and osteochon-dral defects in the knee joint. The authors previously reported on the histologic and radiologic outcome of autologous chondro-cyte implantation in the short- to midterm, which yields mixed results. Purpose The objective is to report on the clinical outcome of autologous chondrocyte implantation for the knee in the midterm to long term. Study Design Cohort study; Level of evidence, 3. Methods Eighty patients who had undergone autologous chondrocyte implantation of the knee with mid- to long-term follow-up were analyzed. The mean patient age was 34.6 years (standard deviation, 9.1 years), with 63 men and 17 women. Seventy-one patients presented with a focal chondral defect, with a median defect area of 4.1 cm2 and a maximum defect area of 20 cm2. The modified Lysholm score was used as a self-reporting clinical outcome measure to determine the following: (1) What is the typical pattern over time of clinical outcome after autologous chondrocyte implantation; and (2) Which patient-related predictors for the clinical outcome pattern can be used to improve patient selection for autologous chondrocyte implantation? Results The average follow-up time was 5 years (range, 2.7-9.3). Improvement in clinical outcome was found in 65 patients (81%), while 15 patients (19%) showed a decline in outcome. The median preoperative Lysholm score of 54 increased to a median of 78 points. The most rapid improvement in Lysholm score was over the 15-month period after operation, after which the Lysholm score remained constant for up to 9 years. The authors were unable to identify any patient-specific factors (ie, age, gender, defect size, defect location, number of previous operations, preoperative Lysholm score) that could predict the change in clinical outcome in the first 15 months. Conclusion Autologous chondrocyte implantation seems to provide a durable clinical outcome in those patients demonstrating success at 15 months after operation. Comparisons between other outcome measures of autologous chondrocyte implantation should be focused on the clinical status at 15 months after surgery. The patient-reported clinical outcome at 15 months is a major predictor of the mid- to long-term success of autologous chondrocyte implantation.

Autologous Bone Plug Supplemented With Autologous Chondrocyte Implantation in Osteochondral Defects of the Knee

Background: Structural and functional outcome of bone graft with first- or second-generation autologous chondrocyte implantation (ACI) in treating cartilage and subchondral bone defect has not been reported previously. Purpose: To evaluate the outcome of simultaneous transplantation of an autologous bone plug with first- or second-generation ACI for restoration of concomitant subchondral bone and full-thickness cartilage defect in the femoral condyle of the knee. Study Design: Case series; Level of evidence, 4. Methods: Seventeen patients (mean ± SD age, 27 ± 7 years; range, 17-40 years)—12 with osteochondritis dissecans (International Cartilage Repair Society [ICRS] grades 3 and 4) and 5 with an isolated osteochondral defect (ICRS grade 4)—had the defect reconstructed with implantation of a unicortical autologous bone graft combined with ACI (the OsPlug technique). Functional outcome was assessed with Lysholm scores obtained preoperatively and at 1 and 5 years postoperatively. The repair site was evaluated with the Oswestry Arthroscopy Score (OAS), MOCART score (magnetic resonance observation of cartilage repair tissue), and ICRS II histology score. Formation of a subchondral lamina and lateral integration of the bone grafts were evaluated from magnetic resonance imaging scans. Results: The mean defect size was 4.5 ± 2.6 cm2 (range, 1-9 cm2), and the mean depth was 11.3 ± 5 mm (range, 5-18 mm). The preoperative Lysholm score improved from 45 (interquartile range [IQR], 24; range, 16-79) to 77 (IQR, 28; range, 41-100) at 1 year (P = .001) and 70 (IQR, 35; range, 33-91) at 5 years (P = .009). The mean OAS of the repair site was 6.2 (range, 0-9) at a mean of 1.3 years. The mean MOCART score was 61 ± 22 (range, 20-85) at 2.6 ± 1.8 years. Histology demonstrated generally good integration of the repair cartilage with the underlying bone. Poor lateral integration of the bone graft, as assessed on magnetic resonance imaging scan, and a low OAS were significantly associated with a poor Lysholm score and failure. A total of 3 patients had treatment failure, with 1 requiring total knee replacement at 5 years (Lysholm score of 33 at failure) and the other 2 requiring further surgical intervention because of persistent symptoms at 2 and 4 years, respectively (both had Lysholm score of 45 at failure). The Lysholm score in these patients before failure were still noted to be higher than at the preoperative level. Conclusion: The OsPlug technique shows significant improvement of functional outcome for up to 5 years in patients with high-grade osteochondritis dissecans or osteochondral defect. This is the first report describing association of bone graft integration with functional outcome after such a procedure. It also demonstrates histologic evidence of integration of the repair cartilage with the underlying bone graft.

Serum from Patients Anesthetized with Opiates Less Effective in the Support of Chondrocyte Growth in Vitro

Risk of viral and/or prion disease transmission associated with the use of fetal bovine serum in clinical cell culture has led to the increasing use of autologous human serum in tissue engineering. A relatively large volume of blood is needed and so, to decrease patient discomfort, we have investigated the feasibility of taking blood when the patient is anesthetized. Two serum samples were prepared from each of 22 patients: (1). from the awake patient (PRE) and (2). from the patient 5 min after induction of general anesthesia (PER). The sera were compared for their ability to support the in vitro proliferation of primary human chondrocytes, determined by cell counting. The effects of anesthetic agents on the PER/PRE cell number ratio were established by analysis of variance and stepwise multilinear regression analysis. The PER sample supported higher growth in 2 of 22 patients, equivalent growth in another 11, and significantly lower growth in the remaining 8. Only the opiate analgesics (fentanyl [Sublimaze], alfentanyl [Rapifen], and diamorphine) had a significant and inhibitory effect on chondrocyte proliferation. It is suggested that opiate analgesics be avoided when blood is taken to support the in vitro growth of human cells.

Efficacy and safety of autologous cell therapies for knee cartilage defects (autologous stem cells, chondrocytes or the two): randomized controlled trial design

AIM The main aim of this trial is to test the safety and efficacy of autologous stromal/stem cells, chondrocytes or the two combined in the treatment of knee cartilage defects. PATIENTS & METHODS Patients with symptomatic chondral/osteochondral defects will be randomized to cell therapy treatment with one of three cell populations (1:1:1). The primary efficacy outcome is a functional knee score (Lysholm) at 15 months post-treatment and the primary safety outcome is the incidence of adverse events. Secondary objectives are to analyze repair tissues, quality of life and cost-utility assessments. Exploratory objectives are to identify predictors for success/potency and dose-response relationships. RESULTS & CONCLUSION This trial has been carefully designed so that valuable scientific and clinical information can be gathered throughout and in the final analysis.