[Treatment of osteochondral defects of the knee with autologous bone graft and chondrocyte transplantation: an overview together with our results]

OBJECTIVES

Iliac bone grafting and matrix-guided autologous chondrocyte implantation (MACI) can be combined to treat large osteochondral defects of the knee. In this prospective study, we evaluated clinical and magnetic resonance imaging (MRI) findings after one and two years of this treatment method.

METHODS

The study included 12 patients who completed a follow-up period of two years. Preoperative arthroscopic and MRI studies revealed grade 3 or 4 osteochondritis dissecans in all the cases. In the first operation, a deep debridement of the sclerotic subchondral bone was performed, followed by press-fit filling of the defect with cancellous bone. In the second operation, a double-layer MACI was fixed within the defect with fibrin glue. The clinical outcomes were evaluated using clinical scores.

RESULTS

The clinical outcomes before and 24 months after surgery were as follows: the mean Meyers score increased from 10.2 to 18, Lysholm-Gillquist score increased from 56.6 to 100, and Tegner-Lysholm score increased from 1.8 to 4. These scores did not show notable changes after 12 months. On MRI images, subchondral edema within the bone graft disappeared until the sixth month. Within a year, MRI signal intensity of the cartilage repair tissue well approximated to that of the healthy surrounding cartilage. The thickness of the cartilage repair tissue increased from 1 mm to 1.8 mm within 6 to 12 months.

CONCLUSION

Matrix-guided autologous chondrocyte implantation combined with bone grafting may be successfully used in remodeling the joint surface, without causing donor site morbidity within the knee joint. In addition, subchondral pathologic alterations may be effectively treated. Magnetic resonance imaging is a reliable technique to evaluate the repair process.

Application of osteochondral autografts and allografts in the treatment of articular cartilage lesions in animals

The paper describes current views on the use of osteochondral autografts and allografts in the treatment of articular cartilage lesions in animals. It presents surgical techniques of grafting and the biological features of osteochondral auto- and allografts, and their effect on the recipient's cartilage.

[Osteochondral allograft transplantation in the knee]

Despite significant improvements for the past 20 years in the treatment of full-thickness chondral defects with the use of chondroprotective biological methods (microfracture, autologous chondrocyte transplantation, osteochondral autograft, and periosteal graft), the treatment of large osteochondral defects in young and physically active population is still challenging. Alternatives for the treatment of chondral defects exceeding 3 cm in size are limited, and among them, allografts have been used longer than any other treatment methods with the most favorable results. The success rates for osteochondral allograft transplantation have been reported as 95%, 71%, and 66% at 5, 10, and 20 years, respectively. Factors that adversely affect long-term results include advanced age, allograft transplantation to both sides of the joint, inappropriate loading, osteoarthritis, and osteonecrosis due to steroid use. Today, as a result of improvements in tissue-organ transplantation, increased availability of fresh tissue from donors, and increased demand from patients and physicians, there has been growing interest in the use of osteochondral allografts in selected patients to delay arthroplasty for chondral defects.

[Autologous osteochondral transplantation]

The surface of diarthrodial joints is covered by hyaline cartilage whose regeneration capacity is extremely limited. Conventional surgical techniques enable repair of full-thickness articular cartilage defects only by fibrous cartilage having poor mechanical properties. Recently, new techniques have been developed to provide hyaline or hyaline-like repair tissue in the treatment of full-thickness cartilage defects. Autologous osteochondral transplantation involves press-fit implantation of both bone and cartilage obtained from healthy articular surface. The principal indication for this technique is unifocal full-thickness chondral or osteochondral defects measuring 1 to 4 square centimeters. This surgical procedure can be performed openly or arthroscopically. The graft should be placed vertically and evenly to the joint surface. Although short-term and mid-term results are satisfactory, several problems have been reported including donor site morbidity, damage to cartilage, and incongruity and incorporation of the graft. Autologous osteochondral transplantation provides viable osteochondral units at a single stage and eliminates the need for culturing chondrocytes which is quite expensive. Currently, no surgical technique or medical treatment provide complete healing of articular cartilage defects. Autologous osteochondral transplantation is an important stage worthy of improvement in this respect.

Articular cartilage: injury pathways and treatment options

Articular cartilage injury and degeneration is a frequent occurrence in synovial joints. Treatment of these articular cartilage lesions are a challenge because this tissue is incapable of quality repair and/or regeneration to its native state. Nonoperative treatments endeavor to control symptoms, and include anti-inflammatory medication, viscosupplementation, bracing, orthotics, and activity modification. Techniques to stimulate the intrinsic repair (fibrocartilage) process include drilling, abrasion, and microfracture of the subchondral bone. Currently, the clinical biologic approaches to treat cartilage defects include autologous chondrocyte implantation, periosteal transfer, and osteochondral autograft or allograft transplantation. Newer strategies employing tissue engineering being studied involve the use of combinations of progenitor cells, bioactive factors, and matrices, and the use of focal synthetic devices. Many new and innovative treatments are being explored in this exciting field. However, there is a paucity of prospective, randomized controlled clinical trials that have compared the various techniques, treatment options, indications and efficacy.

Autologous chondrocyte implantation: natural history of postimplantation periosteal hypertrophy and effects of repair-site debridement on outcome

PURPOSE

Our purposes were to report the clinical outcome of autologous chondrocyte implantation (ACI) patients with graft hypertrophy compared with that of unoperated ACI patients and to longitudinally assess the effects of graft hypertrophy debridement.

METHODS

We divided 170 knee ACI patients with a minimum of 2 years' follow-up into groups according to the need for reoperation after ACI and the findings at surgery. Group A (n = 73) comprised patients who did not undergo reoperation, group B (n = 61) comprised patients who underwent reoperation and had findings unrelated to the repair, and group C (n = 36) comprised patients who underwent reoperation and had isolated graft hypertrophy. The International Knee Documentation Committee, modified Cincinnati knee rating, and Short Form 36 physical component scores for the 3 groups were compared. Of the repairs debrided because of graft hypertrophy, 41 were longitudinally assessed with arthroscopy or magnetic resonance imaging.

RESULTS

The mean follow-up was 42.2 months. Patch-related problems were seen in 73.7% of cases undergoing reoperation less than 2 years after implantation, whereas cartilage-related problems were the dominant finding more than 2 years after implantation (70.2%). Group A patients fared significantly better than group B or C patients with regard to all 3 parameters measured, with no difference between groups B and C. Longitudinal assessment of 41 hypertrophied repairs revealed 18 with signs of pathology after graft debridement.

CONCLUSIONS

This study shows that reoperation is frequent after ACI and is associated with a less satisfying outcome. Furthermore, debridement of a hypertrophied ACI graft appears to be detrimental as shown by longitudinal assessment of repairs.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

Repair of superficial osteochondral defects with an autologous scaffold-free cartilage construct in a caprine model: implantation method and short-term results

OBJECTIVE

To compare four different implantation modalities for the repair of superficial osteochondral defects in a caprine model using autologous, scaffold-free, engineered cartilage constructs, and to describe the short-term outcome of successfully implanted constructs.

METHODS

Scaffold-free, autologous cartilage constructs were implanted within superficial osteochondral defects created in the stifle joints of nine adult goats. The implants were distributed between four 6-mm-diameter superficial osteochondral defects created in the trochlea femoris and secured in the defect using a covering periosteal flap (PF) alone or in combination with adhesives (platelet-rich plasma (PRP) or fibrin), or using PRP alone. Eight weeks after implantation surgery, the animals were killed. The defect sites were excised and subjected to macroscopic and histopathologic analyses.

RESULTS

At 8 weeks, implants that had been held in place exclusively with a PF were well integrated both laterally and basally. The repair tissue manifested an architecture similar to that of hyaline articular cartilage. However, most of the implants that had been glued in place in the absence of a PF were lost during the initial 4-week phase of restricted joint movement. The use of human fibrin glue (FG) led to massive cell infiltration of the subchondral bone.

CONCLUSIONS

The implantation of autologous, scaffold-free, engineered cartilage constructs might best be performed beneath a PF without the use of tissue adhesives. Successfully implanted constructs showed hyaline-like characteristics in adult goats within 2 months. Long-term animal studies and pilot clinical trials are now needed to evaluate the efficacy of this treatment strategy.

Compositional variation of fibrous callus and joint cartilage in different internal environments

OBJECTIVE

To evaluate the compositional variation of fibrous callus in the fracture site and the joint cavity and joint cartilage after being transplanted in the muscle pouch.

METHODS

Thirty 2 month old New Zealand white rabbits (weighing 1-1.5 kg) were randomly divided into two groups: a callus transplantation group (Group A, n=15) and a cartilage transplantation group (Group B, n=15). In Group A, closed radius fracture was made and the autologous fibrous callus was transplanted in the right knee joint cavity at 12 days postoperatively. In Group B, the right knee joint cartilage of the animals was transplanted in the autologous back muscle pouches under anesthesia. Then all the animals were killed by overdose anesthetic 3 weeks after transplantation. And the transplanted fibrous callus, the healed bones in the fracture sites and the transplanted joint cartilage were obtained for assessment of compositional variation.

RESULTS

Pure fibrous composition was found in the callus at the fracture sites in Group A at 12 days postoperatively. And for 11 out of the 15 animals, the fibrous callus was transformed into cartilaginous tissues after 3 weeks of transplantation, but the fibrous callus was absent in the other 4 animals. The fibrous calluses at the original site and the fracture locus were differentiated into bony tissues. Bony tissue transformation was found in the transplanted joint cartilages in the muscle pouch of all the animals in Group B.

CONCLUSIONS

The fracture sites or joint cavity may facilitate callus differentiation in different ways: the former is helpful for osteogenesis while the latter for the development and maintenance of cartilages, and the muscle pouch is inclined to induce the osteogenic phenotype for cartilages.

[Osteochondritis dissecans of the knee joint]

Osteochondritis dissecans is a disorder with a prevalence of 0.01 to 0.06 %. Men between 16 and 36 years of age are most commonly affected by it. In the western hemisphere, the knee is affected by this progressive disorder in 75 % of the cases, specifically the medial femoral condyle (70 - 80 %). The etiology is uncertain, although genetic defects, micro-trauma, ossification disorders and ischemia have been implicated. Pathogenetically, Osteochondritis dissecans is classified in four stages, whereas in stage one, there is merely a subchondrial edema. Without therapy this could lead to stage 4, with a free osteochondral joint fragment. Treatment is analogous with the stage of the disorder. Whereas conservative treatment may yield full recovery during stage 1, starting in stage 2, invasive treatment should be considered. When the cartilage surface remains intact retrograde procedures are indicated. If the cartilage is injured anterograde therapies, like the chondral or osteochondral transplantation, should be used.

[Focal osteochondral necrosis of the femoral head of an adult after Legg-Calve-Perthes disease in childhood]

In the treatment of circumscribed osteochondral lesions of the knee and the ankle joint autologous osteochondral transplantation (AOT) has been established as one of the possible operative therapies. However, there is less experience with the use of AOT on other joints (shoulder, elbow). The care of osteochondral defects of the hip joint with autologous osteochondral transplantation can still be regarded as an absolute rarity. Facing a focal osteochondral necrosis in a young female adult after LCP disease in childhood, we report about an autologous osteochondral transplantation at the femoral head using the diamond bone cutting system.

Primary total knee arthroplasty with condylar allograft and MCL reconstruction for a comminuted medial condyle fracture in an arthritic knee--a case report

Fractures of the distal femur in the elderly are usually due to low energy ground level fall onto a flexed knee. Pre-existing osteoarthritis and juxta-articular osteopenia in this age group result in high levels of comminution and articular damage at the time of injury, which challenges the management and treatment outcome. Preservation of knee function and early weight bearing should be the objectives of management in the geriatric population. We present in this case report of an elderly patient with comminuted medial condyle fracture with arthritic changes who had primary total knee arthroplasty utilizing condylar allograft and MCL reconstruction as an alternative to internal fixation.

[Biomaterials and cell therapy in cartilage disorders]

Joint cartilage has a poor intrinsic ability to heal. Common surgical treatments for traumatic lesions, after debridement of the chondral defect, include stimulation of subchondral bone (microfracture), perichondrial or periosteal grafting, and mosaicplasty (osteochondral cylinder transplantation). Autologous chondrocyte transplantation (ACT) was the first application of cell therapy to orthopaedic surgery. Despite promising results, several groups have tested tissue engineering protocols based on ex vivo colonization of biodegradable polymer matrices that are subsequently transplanted to the target site. Tissue engineering as a treatment for osteoarthritis is even more challenging. Transplantation of genetically modified cells is an interesting concept, based on the production of therapeutic proteins directly at the target site.

Treatment of full-thickness chondral defects in the knee with autologous chondrocyte implantation

Autologous chondrocyte implantation (ACI) has now been performed for over a decade in the United States. ACI has been demonstrated as a reproducible treatment option for large, full-thickness, symptomatic chondral injuries of the knee. As clinical experience has expanded and indications broadened to more complex cartilage defects, it has become evident that aggressive treatment of coexisting knee pathology is essential for optimal results. This includes management of malalignment, ligamentous, and/or meniscal deficiency, and subchondral bone loss to make the intra-articular environment as ideal as possible for successful cartilage restoration. Additionally, refinements in the rehabilitation necessary for biologic cartilage repair have been made, based on better understanding of the maturation process of the repair cartilage, allowing for earlier initiation of knee range of motion, strengthening exercises, and weight bearing. These changes have enhanced the recovery for the patient and decreased the risk of motion deficits. This article will discuss patient selection for ACI, review ACI surgical technique, including management of coexisting knee pathology, present postoperative ACI rehabilitation guidelines, and summarize clinical outcomes after ACI.

Strategies to Promote Chondrogenesis and Osteogenesis from Human Bone Marrow Cells and Articular Chondrocytes Encapsulated in Polysaccharide Templates

The aim of this study was to synthesize functional in vitro and in vivo 3-dimensional (3D) constructs using a mix of human mesenchymal populations and articular chondrocytes encapsulated in biomineralized polysaccharide templates. Single-cell-type populations or mixtures of both cell types were encapsulated in alginate/chitosan and cultured within a rotating-bioreactor, perfused bioreactor system, or static conditions for 28 days. Within single cell-type populations, type II collagen immunopositive cells were present within lacunae in rotating-bioreactor capsules, with an increased proportion of metabolically active cells compared with perfused and static constructs. Biochemical analysis indicated significantly increased ( p < 0.05) DNA and protein in rotating-bioreactor conditions compared with perfused or static. However, in coculture samples, DNA and protein was significantly increased in static cultures owing to the formation of large regions of partially mineralized osteoid. This osteoid was found only in static cultures and when the ratio of human bone marrow cells to chondrocytes was 2:1 or, to a lesser extent, 5:1 ratio capsules. Subcutaneous implantation of capsules into immunocompromised mice also showed optimal osteoid formation when the ratio was 2:1. The current studies demonstrate the pivotal role of robust 3D biomimetic microenvironments and indicate the potential to harness the interactions between different cell types to create specific tissues.

[Articular reconstructions by a costochondral grafting (or osteochondral costal grafting)]

We describe a novel technique of costochondral autografting for the treatment of trapeziometacarpal arthritis, radioscaphoid osteoarthritis, malunion of the distal end of the radius, and osteoarticular loss of the MP joints of long fingers. The costal graft harvest technique is always the same. A 5-cm horizontal incision is made over the 9th rib, and the rib is exposed at the osteocartilaginous junction. Cartilaginous grafts are harvested with a scalpel, and osteocartilaginous grafts with a saw. Since 1992, 116 patients with trapezio-metacarpal arthritis have been treated by partial trapeziectomy and autologous rib cartilage grafting. One hundred patients were reviewed with an average follow-up of 5.6 years. The results were better than those of trapeziectomy with tendon interposition or ligamentous reconstruction, owing to good stability of the thumb ray height. For the treatment of radioscaphoid osteoarthritis following scaphoid non union or chronic scapholunate instability, partial carpal arthrodesis and resection of the first row are the classical techniques. As an alternative to these procedures, 18 patients were treated by resection of the proximal portion of the scaphoid and insertion of an osteochondral costal autograft. Mean follow-up is 4.1 years. The results are excellent or good in 15 cases, fair in 2 cases, and poor in 1 case (luxation of the graft). Four patients with articular malunion of the distal radius received an osteocartilaginous costal graft to reconstruct the articular surface of the radius while avoiding partial or total arthrodesis of the wrist. Four patients with segmental osteoarticular loss of the longfingers were treated with the same technique, thereby avoiding silicone arthroplasty. We review the literature on cartilaginous rib grafts in maxillofajcial and orthopaedic surgery. In our experience, MRI and biopsy show viable cartilage but also histologic changes such as revascularization, fibrous transformation and bone metaplasia.

Osteochondral lesions of the talus: randomized controlled trial comparing chondroplasty, microfracture, and osteochondral autograft transplantation

PURPOSE

The purpose of this study was to compare outcomes of chondroplasty versus microfracture versus osteochondral autologous transplantation (OAT) in patients with osteochondral lesions of the talus (OLT).

METHODS

After prospective sample size analysis, patients with symptomatic, recalcitrant Ferkel class 2b, 3, and 4 OLT were randomized to chondroplasty, microfracture, or OAT treatment groups. Outcomes were measured with use of the American Orthopaedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot Scale (AHS), the Subjective Assessment Numeric Evaluation (SANE) rating, Numeric Pain Intensity (NPI), and magnetic resonance imaging (MRI).

RESULTS

Eleven patients had chondroplasty, 10 ankles (9 patients) had microfracture, and 12 patients had OAT. Mean time to follow-up was 53 months (range, 24 to 119 months). AHS scores showed no differences at 12 and 24 months, and SANE ratings showed no differences at final follow-up. NPI was significantly lower (P < .001) in chondroplasty and microfracture cases as compared with OAT at 24 hours postoperatively. Pearson's correlation analysis demonstrated an inverse relation between microfracture and OAT groups in that better outcome was associated with smaller lesions, compared with the chondroplasty group, which revealed mixed results with no particular trend. MRI revealed incomplete fill and edema after chondroplasty or microfracture and chondral gaps after OAT.

CONCLUSION

Our results demonstrate no difference between chondroplasty, microfracture, and OAT with regard to AHS and SANE ratings in patients with OLT. However, NPI at 24 hours postoperatively was significantly lower in patients who had chondroplasty and microfracture.

LEVEL OF EVIDENCE

Level I, Therapeutic study, high-quality randomized controlled trial with no statistically significant differences but narrow confidence interval.

Repair of pectus deformities: experience and outcome in 317 cases

BACKGROUND

The most common congenital chest wall deformities are pectus excavatum and pectus carinatum. Various techniques have been described for correction of pectus deformities. We describe our experience with surgical repair of pectus deformity (PD) in adults, including our new technique, which uses a resorbable plaque for fixation of the sternum.

METHODS

We reviewed the records of 317 patients who underwent surgical correction of PD between October 1997 and December 2005.

RESULTS

All of the patients were male and the median age was 21.3 years (range, 16-32 years). Of 317 patients, the type of deformity was a pectus excavatum in 230 patients and a pectus carinatum in 87 of the patients. Four different operative techniques were used. There were no intraoperative deaths or major perioperative morbidity. The complications rate was 17%. Overall mean hospital stay was 14.25 days. In 208 patients who underwent a mid-term outpatient follow up (mean, 8 months), there was no recurrence. Patient satisfaction was excellent in 234 patients, good in 79 patients and fair in 4 patients.

CONCLUSION

The majority of patients with pectus deformity had been operated on during childhood; therefore there is limited published information about the correction of pectus excavatum and pectus carinatum deformities in adults. The most important point in pectus correction is to achieve proper and long-term stability of the sternum following osteotomy. Various techniques can be used for this purpose.

Osteochondral autologous transplantation versus microfracture for the treatment of articular cartilage defects in the knee joint in athletes

The purpose of this prospective randomized clinical study was to compare the outcomes of mosaic type autologous osteochondral transplantation (OAT) and microfracture (MF) procedures for the treatment of the articular cartilage defects of the knee joint in athletes. Between 1998 and 2002, a total of 57 athletes with a mean age of 24.3 years and with a symptomatic lesion of the articular cartilage in the knee were randomized to undergo either OAT or MF procedure. There were 28 athletes in OAT group and 29 in MF group. Patients were evaluated using a modified Hospital for Special Surgery (HSS) and International Cartilage Repair Society (ICRS) scores, MRI and clinical assessment after 6, 12, 24 and 36 months after the surgery. According to the modified HSS and ICRS scores, functional and objective assessment showed that 96% had excellent or good results after OAT compared with 52% after MF procedure (P<0.001). In 12, 24 and 36 months after the operations, the HSS and ICRS showed statistically significantly better results in the OAT group (P=0.03; P=0.006; P=0.006). Twenty-six (93%) athletes following OAT and fifteen (52%) athletes following MF returned to sports activities at the preinjury level at an average of 6.5 months (range, 4-8 months) after the operations. At an average of 37.1 months follow-up, our prospective, randomized, clinical study in athletes has shown significant superiority of the OAT over MF for the repair of articular cartilage defects in the knee.

Mapping of donor and recipient site properties for osteochondral graft reconstruction of subchondral cystic lesions in the equine stifle joint

REASONS FOR PERFORMING STUDY

To improve osteochondral graft reconstruction of subchondral cystic lesions in the medial and lateral femoral condyles by matching the material properties of donor and recipient sites.

OBJECTIVES

To measure biomechanical and biochemical parameters that influence the function and healing of osteochondral grafts used to reconstruct subchondral cystic lesions.

HYPOTHESIS

Suitable donor sites are available within the stifle joint for reconstructing the femoral condyles, despite considerable regional property variation.

METHODS

Fifty-six osteochondral cores were harvested from 6 distal femurs for initial studies that determined subchondral bone modulus of elasticity and ultimate stress. In a second study, 28 osteochondral cores were harvested from 6 distal femurs to measure cartilage aggregate modulus, thickness and sulphated glycosaminoglycan (sGAG) content. Using micro-CT imaging, subchondral bone mineral density and bone volume fraction were also measured. In both studies 2-dimensional contour plots using a bicubic interpolation method and normalised data were generated to allow visual comparison of joint surface characteristics. Statistical comparisons between donor and recipient site raw data were made using an ANOVA for repeated measures with a post hoc Tukey test.

RESULTS

Material properties of cartilage and bone vary considerably over the surface of the stifle joint but the central region of the medial condyle, where subchondral cystic lesions freqdently occur, typically demonstrated bone strength and modulus values of the highest observed. Cartilage thickness and aggregate modulus were highest in the medial femoral condyle and axial aspect of the lateral condyle.

CONCLUSIONS

Material properties of the grafts from the trochlear groove and axial aspect of the lateral trochlear ridge were the closest match for those found in the medial condyle, whereas properties of the lateral condyle were most similar to those found in the trochlear groove and axial aspect of the medial trochlear ridge.

Die Verwendung von frischen Allografts bei der Osteochondrosis dissecans am lateralen Femurkondylus

OBJECTIVE

Reconstruction of joint surface by using allografts to fill extensive bone-cartilage defects.

INDICATIONS

Bone-cartilage defects ranging from a diagonal length of at least 3 cm and a depth of minimum 1 cm to maximum the entire lateral femoral condyle, e. g., following trauma, in the case of osteochondrosis dissecans, or following the resection of benign tumors.

CONTRAINDICATIONS

Arthrosis. Minor or superficial cartilage defects. Bipolar defects.

SURGICAL TECHNIQUE

The transplant bed is reamed precisely into the recipient's knee, the donor knee is opened, the block required for transplantation is measured, prepared and press-fit inserted. A straight leg axis is required for a good surgical result.

POSTOPERATIVE MANAGEMENT

No weight bearing on the operated leg, two underarm crutches for 10 weeks, then partial weight bearing and further increase in weight bearing depending on postoperative allograft healing. CT follow-ups to assess postoperative healing of the transplant after 3 and after 8-12 months. Sporting activities that put pressure on the knee joint should not be undertaken until at least 1 year after surgery; cycling and swimming-depending on the CT-from the 6th postoperative month onward.

RESULTS

Three male patients aged 21 (n = 2) and 28 (n = 1) were operated on for osteochondrosis dissecans of the lateral femoral condyle and observed for an average of 26 months. Postoperative healing of the transplanted tissue was confirmed in all patients by means of CT. For two of them, the vitality of the transplant was confirmed by means of MRT and contrast agents, and good postoperative healing of the transplant was also represented arthroscopically. All patients were subjectively satisfied, without complaints, and had improved range of motion in the operated knee.

Autologous cartilage implantation for full thickness articular cartilage defects of the knee

BACKGROUND

Treatments for managing articular cartilage defects of the knee, including drilling and abrasion arthroplasty, are not always effective. When they are, long-term benefits may not be maintained and osteoarthritis may develop, resulting in the need for a total knee replacement. An alternative is the surgical implantation of healthy cartilage cells into damaged areas (autologous cartilage implantation).

OBJECTIVES

To determine the effectiveness of autologous cartilage implantation (ACI) in people with full thickness articular cartilage defects of the knee.

SEARCH STRATEGY

We searched the Cochrane Bone, Joint and Muscle Trauma Group Specialised Register (15 December 2005), the Cochrane Central Register of Controlled Trials (The Cochrane Library, Issue 3, 2005), MEDLINE (1966 to December 2005), CINAHL (1982 to December Week 2, 2004), EMBASE (1988 to 2005 Week 50), SPORTDiscus (1830 to January 2005) and the National Research Register Issue 3, 2005.

SELECTION CRITERIA

Randomised and quasi-randomised trials comparing ACI with any other type of treatment (including no treatment or placebo) for symptomatic cartilage defects of the medial or lateral femoral condyle, femoral trochlea or patella.

DATA COLLECTION AND ANALYSIS

Two review authors selected studies for inclusion independently. We assessed study quality based on adequacy of the randomisation process, adequacy of the allocation concealment process, potential for selection bias after allocation and level of masking. Data was not pooled due to clinical and methodological heterogeneity in the studies.

MAIN RESULTS

We included four randomised controlled trials (266 participants). One trial of ACI versus mosaicplasty reported statistically significant results for ACI at one year, but only in a post-hoc subgroup analysis of participants with medial condylar defects; 88% had excellent or good results with ACI versus 69% with mosaicplasty. A second trial of ACI versus mosaicplasty found no statistically significant difference in clinical outcomes at two years. There was no statistically significant difference in outcomes at two years in a trial comparing ACI with microfracture. In addition, one trial of matrix-guided ACI versus microfracture did not contain enough long-term results to reach definitive conclusions.

AUTHORS' CONCLUSIONS

The use of ACI and other chondral resurfacing techniques is becoming increasingly widespread. However, there is at present no evidence of significant difference between ACI and other interventions. Additional good quality randomised controlled trials with long-term functional outcomes are required.

Short-duration enzymatic treatment promotes integration of a cartilage graft in a defect

OBJECTIVES

Surgical manipulation of cartilage tissue is associated with chondrocyte death in the wound edges that hinders integration. The objective of this study was to evaluate the effect of a short course of treatment of a cartilage graft with a combination of hyaluronidase and collagenase on chondrocyte density and integrative capacity.

METHODS

Cartilage explants were treated with enzymes for various time periods and at various concentrations. A central core was punched out of a larger explant, treated with enzymes, reimplanted, and placed subcutaneously in athymic mice. The number of chondrocytes in the wound edges was counted, and the integrative capacity of the grafts was evaluated by histology.

RESULTS

Treatment with collagenase for 48 hours led to a significant increase in the number of vital chondrocytes and restored it to normal after 14 days of culture. Treatment with hyaluronidase and collagenase for 48 hours further increased chondrocyte densities to supranormal values. Shortening the treatment to 1 hour restored the chondrocyte density to normal after 14 days of culture. In vivo integration experiments showed increased chondrocyte densities in treated wound edges and extracellular matrix fibers crossing over from enzyme-treated parts to untreated parts.

CONCLUSIONS

Short-duration treatment of a cartilage graft with a combination of hyaluronidase and collagenase increases cell density at wound edges and promotes integrative repair.

Cartilage transplantation

Chondral injuries are common sequelae following musculoskeletal trauma. This article reviews different techniques of cartilage regeneration undertaken in the past, and focuses on the recent advances in the field of tissue engineering.