Osteochondral defects of the talus treated with fresh osteochondral allograft transplantation

Between 1980 and 1996, 9 patients with osteocartilagenous lesions of the talus were treated surgically using fresh osteochondral allograft transplantation. In 8 cases the reason for surgery was osteochondritis dissecans (4 of these cases had a previous traumatic injury). In 1 case a fresh osteochondral allograft of the talus was required following a traumatic open fracture of the talus sustained in a motor vehicle accident. Of these 9 grafts, 6 grafts remain in situ with a mean survival of 11 years (range 4 to 19). In the three cases requiring fusion the reason for surgery was not related to arthritic deterioration but due to resorption and fragmentation of the graft.

[Microtia: technique for external ear reconstruction with autologous rib cartilage]

Various methods for treatment of classic microtia are known. Beside a prosthesis, the most common way of auricle reconstruction is the use of autogenous rib cartilage; a process that requires two to three operations. In the first operation, rib cartilage is harvested from the 6th to the 9th rib. The base of the framework is the 6th and 7th rib cartilage which is taken under preservation of the synchondrosis. To mimic a 3-dimensional structure, the triangular fossa and scapha are carved into the groundplate and the 8th rib is fixed as a helical rim. After optimising the framework, it is placed in a subcutaneous pocket on the mastoid plane. In a second operation, approximately three months later, the auriculocephalic angle is reconstructed with a cartilage wedge, which is covered by a temporalis fascia flap and split skin-graft from the hairbearing skull. Commonly, a third operation is needed for minor refinements. Currently, autogenous rib cartilage is the ideal material available for ear reconstruction resulting in an excellent cosmetical outcome, although harvesting of the cartilage causes a specific donor-site morbidity. Operations improving the hearing ability by building up the external hearing channel and middle ear are mainly done in cases of bilateral microtia. Ear reconstruction with autogenous rib cartilage produces a replicable aesthetic result. The patients should be at least eight years old.

Technical considerations in periosteal grafting for osteochondral injuries

Periosteum has been used clinically for biologic resurfacing arthroplasty in small series of patients for almost two decades. The author's own experience with this technique in multiple joints, including the knee, has been similar to that already reported in the literature. Observations and considerations are discussed that might help avoid failure in future applications of this technique. Indications and surgical technique, including graft procurement and fixation, and postoperative treatment and possible complications are also described. The rationale for using periosteum as a chondrogenic tissue and the factors affecting its cartilage production are also outlined.

Treatment of osteochondral injuries. Genetic engineering

Articular cartilage injuries are commonly encountered problems in sports medicine and orthopaedics. The treatment of chondral and osteochondral lesions, which possess only a very limited potential for healing, still represents a great challenge to clinicians and to scientists. Experimental investigations reported over the last 20 years have shown that a variety of methods, including implantation of periosteum, perichondrium, artificial matrices, growth factors, and transplanted cells, can stimulate formation of new cartilage. Genetic engineering--a combination of gene transfer techniques and tissue engineering--will facilitate new approaches to the treatment of articular cartilage injuries.

Basic science of articular cartilage repair

As the ability to understand the peculiarities of successful healing of articular cartilage defects moves forward, it becomes clear that this complex orthopaedic problem soon will be successfully addressed. A multidisciplinary approach, combining clinical experience, cogent biomaterial designs, new cell biologic processes, biomechanical assessment, and modern molecular biology, clearly is leading toward clinically acceptable, viable, and consistent articular cartilage regeneration.

Comparison of long-term immunosuppression for limb transplantation using cyclosporine, tacrolimus, and mycophenolate mofetil: implications for clinical composite tissue transplantation

This study compared the efficacy of long-term intermittent immunosuppression in preventing the rejection of a limb transplant across the strongest histocompatibility barrier in ACI --> Lewis rats using the conventional immunosuppressive agent cyclosporine-A and the newer immunosuppressive agents FK-506 (tacrolimus) and RS-61443 (mycophenolate mofetil). The recipient animals were immunosuppressed daily for 14 days postoperatively, followed by long-term intermittent, twice-weekly immunosuppression using cyclosporine 25 mg/kg, RS-61443 30 mg/kg, or FK-506 2 mg/kg. All three immunosuppressive agents were able to prolong the rejection of the skin component of a limb transplant compared with nonimmunosuppressed controls. Eight of nine animals receiving cyclosporine immunosuppression showed signs of rejection of the skin component of the limb transplant while continuing to receive long-term immunosuppression and had a mean rejection time of 61.6 days. Seven of 10 animals immunosuppressed with RS-61443 also showed signs of rejection while still receiving immunosuppression, with a mean rejection time of 43.6 days. Nine of 10 animals receiving FK-506 immunosuppression showed no signs of skin rejection, but died of bacterial pneumonia between 273 and 334 days after transplantation, with a mean rejection time of 296.1 days. There was no statistically significant difference between intermittent immunosuppression with cyclosporine and RS-61443, but FK-506 was significantly superior to both cyclosporine and RS-61443. The implication of this study is that FK-506, but not cyclosporine or RS-61443, is probably the only single immunosuppressive agent capable of preventing rejection of the skin component of a composite tissue transplant. Combination immunosuppression with FK-506 and RS-61443, therefore, may be required to allow composite tissue transplantation to become a predictable clinical reality in the future.

Topographic matching of selected donor and recipient sites for osteochondral autografting of the articular surface of the femoral condyles

The purpose of this study was to define the topography of the articular surface of the femoral condyles and to develop a method for computerized topographic matching of donor and recipient sites for osteochondral transplantation. The condyles of seven fresh cadaveric femurs were mounted on the rotating stage of a laser-based coordinate measuring machine. An anatomic coordinate system defining the articular surface of the condyles was created. Customized software was developed to allow selection and topographic matching of osteochondral graft donor and recipient sites from any location on the surface of the condyles. For cartilage defects within the weightbearing portions of the medial or lateral femoral condyles, grafts taken from sites from the most medial or lateral portions of the patellar groove provided a significantly better topographic match than did grafts taken from the central intercondylar notch.

Is there an option for harvesting autologous osteochondral grafts without damaging weight-bearing areas in the knee joint?

Within the past few years autologous osteochondral transplantation has become an established standardized procedure in joint surgery. One significant disadvantage of this technique is the harvesting of the osteochondral grafts from the weight-bearing area of the knee joint. The tibiofibular articulation is located close to the knee joint that is operated on. This articulation is covered with cartilage. The purpose of this study was to evaluate whether this joint is suitable as a donor site for osteochondral grafts. Ten human knee specimens were freed of all soft tissues around the proximal calf. The age of the specimens ranged between 58 and 79 years. Next the tibiofibular articulation was identified, and both the ligaments and the capsule were removed. After opening the joint the tibial- and fibular-sided joint surfaces were inspected and measured. In all specimens the articular surfaces showed good cartilage coverage. In only a single joint did the cartilage macroscopically show degeneration. In all other joints the cartilage surface was in surprisingly good condition, especially considering the age of the specimens. The average diameter of the cartilage surface on the tibial side was 1.7 +/- 0.26 x 1.9 +/- 0.22 cm and on the fibular side 1.6 +/- 0.31 x 1.8 +/- 0.32 cm. This results in an area of cartilage for transplantation of 3.23 cm2 at the tibia and of 2.88 cm2 at the fibula. The total area for cartilage transplantation is 6.11 cm2. The tibiofibular joint contains cartilage, which may be a reasonable donor site even for the elderly patient. Harvesting the graft from this area may avoid iatrogenic damaging of intra-articular weight-bearing cartilage of the knee joint.

Articular cartilage transplantation. Current and future limitations and solutions

The ultimate goal of replacing cartilage with a bioengineered graft, autologous graft, or allograft is to replace the damaged articulating surface with tissue containing the anatomical, biomechanical, and functional properties of native articular cartilage, which will have resultant satisfactory clinical outcome. For transplanted articular cartilage to obtain the original histologic arrangement of hyaline cartilage with secure incorporation into host tissue, progressive integrated multidisciplinary research must continue. Although autologous chondrocyte transplantation of the talus is not yet FDA approved, this technique may provide the surgeons with a cutting-edge method to treat patients with nondegenerative osteochondral lesions of the talus and possibly other articulating joints of the foot.

Polydioxanone biodegradable pins in the knee: MR imaging

OBJECTIVE

Biodegradable solid implants have been developed as an alternative to metallic orthopedic fixation. In animal models, implants degrade within and are replaced by bone. This study documents the resorption of these devices in human patients with MR imaging.

SUBJECTS AND METHODS

One hundred seventy-five 1.3-mm biodegradable pins made of polydioxanone were used to secure a total of 59 osteochondral allografts of the knee. Patients with the pins underwent scanning on a 1.5-T unit with 3.3- to 4-mm contiguous T1-weighted spin-echo (TR/TE, 600/15), fat-saturated proton density-weighted (3000/40), T2-weighted fast spin-echo (3000/63), and three-dimensional spoiled gradient-recalled (47/7; flip angle, 60 degrees ) sequences at 3, 6, 12, 24, or 36 months after surgery. Eighty-nine pins were imaged on multiple occasions. Two osteoradiologists interpreted the MR examinations.

RESULTS

More than 80% of the pin channels were visible at 3 and at 6 months after surgery. By 24 months, only 20% of the pin channels were visible, with the remainder having been replaced by bone. At 3 months, nearly 40% of the pins were associated with adjacent marrow edema. Edema generally diminished, involving less than 20% of pins at later time points. Focal cartilage defects were evident at 32% of the pin insertion sites during the first 6 months, but these defects were present in only 4% of the insertion sites thereafter.

CONCLUSION

Biodegradable polydioxanone pins usually resorb completely by 24 months. Marrow edema, presumably representing inflammation related to pin resorption, is infrequent and tends to resolve. Cartilage defects related to pin placement heal spontaneously.

[Operative therapy of osteochondral lesions of the talus with autologous cartilage-bone transplantation]

Since 1996 we have gained experience in the development and clinical application of the OATS technique in 167 cases. Operative management, technical demands and early results of osteochondral cylindrical autograft plugs at the talus are presented. Between April 1996 and November 2000 we treated 39 patients (21 male, 18 female) with an average age of 28.4 years (range: 16-57 years) for osteochondral defects with an average size of 8 x 15 mm-20 x 15 mm at the medial (n = 31) and lateral (n = 6) talar dome as well as at the distal tibia (n = 2) with an OATS technique. Indications were osteochondral defects after trauma in 12 patients (med., n = 5; lat., n = 5; dist. tibia n = 2) and osteochondrosis dissecans (grades III and IV) in 27 patients (med., n = 26; lat., n = 1). The donor site was the proximal lateral femoral condyle in all patients. An additional osteotomy of the malleolus was necessary in 30 patients. All patients were scored pre- and postoperatively by a Lysholm Bruns score and monitored by postoperative MRI. The follow-up extended for an average of 19.6 months (6-42). The Lysholm score for all patients rose from 62 points (range: 20-77) up to 92 points (range: 63-100). There was no correlation between patients with and without an osteotomy of the malleolus. The postoperative MRI showed a complete incorporation and vitality of the transplanted cylinders as well as a congruence of the joint surface. Complications were pain in three cases in the region of the osteotomy, which decreased after removal of the screws, and synovialitis in one case. One patient reported femoropatellar pain for about 4 weeks. The OATS technique achieves encouraging results in limited osteochondral defects in the talar dome even in preoperated osteochondral defects. Because of the mostly posterior localization of the defect zone, osteotomy of the malleolus is necessary in most cases. Harvesting the donor cylinders from the ipsilateral knee joint by mini-arthrotomy shows a low mortality. The OATS technique is a suitable, causal and cost-effective therapy, which can possibly prevent and at least delay the development of an arthrosis.

An investigation of 2 techniques for optimizing joint surface congruency using multiple cylindrical osteochondral autografts

PURPOSE

To compare 2 techniques for optimizing joint congruency for miniature osteochondral autografting in the knee: intrinsic postoperative forces acting on overdrilled autografts protruding from the femur versus alignment by a surgeon at the time of grafting.

TYPE OF STUDY

Controlled animal model experiment.

METHODS

A full-thickness cartilage defect was created on the weight-bearing surface of the medial femoral condyle of 13 mature sheep. Three 4.5 x 10 mm cylindrical autografts were inserted into 14-mm deep recipient holes such that the grafts were held in place by side-wall friction alone. One treatment group received grafts that were delivered flush with the surrounding cartilage and the second group received grafts that were left 2-mm proud of the joint surface.

RESULTS

Three months postoperatively, the proud grafts had been repositioned by weight bearing but perigraft fissuring and fibroplasia, and subchondral cavitations were serious complications. It is suspected that these complications were caused by excessive motion between the graft and recipient site in the proud grafts.

CONCLUSIONS

Grafts should be delivered flush with the joint surface when performing osteochondral transfers to avoid graft micromotion and the consequent interference with graft integration and function.

Storing live embryonic and adult human cartilage grafts for transplantation using a joint simulating device

OBJECTIVES

Cartilage transplantation as a means to replace damaged articular surfaces is of interest. A major obstacle is the long-term preservation of cartilage grafts. The commonly used technique of freezing the grafts inevitably leads to cellular death. The current study compares the technique to an innovative approach using a pulsed-pressure perfusion system termed a joint simulating device (JSD), intended to simulate intra-articular mechanical forces.

METHODS

Human articular cartilage explants were harvested from both embryonic epiphyseal tissue and femoral heads of elderly women (over 70 years of age) undergoing a partial joint replacement (hemi-arthroplasty) and were divided in two groups: half of the samples were incubated in the JSD while the remaining half were grown in static culture within tissue culture plates. After 10 days all samples were evaluated for: (a) cell vitality as assessed by image analysis and XTT assay; (b) biosynthetic activity as expressed by radioactive sulfate incorporation into glycosaminoglycans (GAG's); and (c) proteoglycan content as assessed by alcian blue staining intensity.

RESULTS

A 10-fold increase in sulfate incorporation in samples held in the JSD compared to the static culture group was observed in embryonic cartilage. In adult cartilage culture in the JSD elevated sulfate incorporation by threefold as compared to static culture. Central necrosis was observed in specimens grown in the static culture plates, while it did not occur in the samples held in the JSD. Cell vitality as assessed by XTT assay was significantly better in the JSD group as compared to static culture. The difference was more pronounced in the embryonic specimens as compared to adult cartilage. The specimens cultured within the JSD retained proteoglycans significantly better than those cultured in static culture.

CONCLUSIONS

Maintenance of cartilage specimens in a JSD was highly effective in keeping the vitality of cartilage explants in vitro over a 10-day period. A possible future application may be a long-term preservation of chondral grafts, without freezing. Avoidance of freezing of cartilage grafts, might prevent the cartilage degeneration often observed in frozen osteochondral grafts.

Articular cartilage nutrition is mediated by subchondral bone: a long-term autograft study in baboons

OBJECTIVE

To determine the relative importance of subchondral nutrition in cartilage in autologous transplants and its relation to the development of osteoarthritis (OA).

METHOD

The study was performed in non-human primates with two types of autografts placed orthotopically. One type of autograft was placed into vascularized, viable cancellous bone well, and another in an identical bone well, but coated with methylmethacrylate. The latter prevented direct contact between the autograft and the host bone. Observations were continued for 3 years.

RESULTS

Abrogation of the contact between subchondral bone and articular cartilage-bone autograft had little effect on the cartilage during the first 5-12 months. By 3 years, autografts in the methylmethacrylate wells had non-vascularized and non-viable subchondral bone. The cartilage in these wells underwent degenerative changes compatible with OA.

CONCLUSION

Interruption of contact between articular cartilage and vascularized subchondral bone resulted in degeneration of the cartilage. The onset and detection of these degenerative changes required long time periods (3 years). Had the experiments been terminated at 1 year or sooner the above described changes would not be apparent.

Report on the 2nd symposium of the International Cartilage Repair Society

The articular cartilage is a unique tissue and a functional articular cartilage is critical to proper joint function. The inability of the articular cartilage to heal traumatic defects with a similar quality tissue has been appreciated since the time of hippocrates. Although a variety of surgical procedures have been developed over the past 50 years in attempt to overcome this treatment challenge, none has been successful in achieving regeneration of normal articular cartilage. It is these treatment challenges that form the reasoning behind the formation of the International Cartilage Repair Society (ICRS) and her 2nd annual symposium is presented.

An investigation of the frequency of co-existence of osteophytes and circumscribed full thickness articular surface defects in the knee joint

Osteophytes are osteochondral repair tissues formed usually at the margins of synovial joints in response to a more central full thickness articular cartilage defect. These defects can be managed using the autologous chondrocytes implantation technique or with composite osteochondral grafting. Materials for osteochondral grafting of circumscribed full thickness articular surface defects may be obtained from osteophytes. In this study, the frequency of co-existence of these two intra-articular lesions was studied prospectively in patients undergoing therapeutic arthroscopy for painful knee conditions. Thirty-three of 88 knees (37.5%) had full thickness articular surface defects and 23 of these (69.7%) had associated osteophytes formation.

High tibial osteotomy and ligament reconstruction for varus angulated anterior cruciate ligament-deficient knees

In a consecutive series, we treated 41 young patients who had anterior cruciate ligament deficiency, lower limb varus angulation, and varying amounts of posterolateral ligament deficiency. Seventy-three percent of the patients (N = 30) had lost the medial meniscus and 63% (N = 26) had marked articular cartilage damage in the medial compartment. All patients were treated with high tibial osteotomy and, in the majority (N = 34), anterior cruciate ligament reconstruction a mean of 8 months later. Posterolateral reconstructions were also required in 18 knees. A 100% follow-up was obtained at a mean of 4.5 years after osteotomy. Gait analysis testing was done in 17 knees before and after osteotomy. At follow-up, a reduction in pain was found in 71% (29 knees); elimination of giving way, in 85% (35 knees); and resumption of light recreational activities without symptoms, in 66% (27 knees). The patient rating of the knee condition was normal or very good in 37% (15 knees) and good in 34% (14 knees). The mean Cincinnati Knee Rating Score significantly improved from 63 to 82 points. The mean adduction moment, 35% higher than controls preoperatively, significantly decreased to below normal values postoperatively. Correction of varus alignment was maintained in 33 knees (80%). We recommend osteotomy in addition to ligament reconstructive procedures in these knees with complex injury patterns.

[Autologous chondrocyte transplantation--from science fiction to routine clinical practice]

Adult articular cartilage lacks the capacity for self-repair. The limiting factor appears to be the inability of chondrocytes to proliferate while embedded in the extracellular matrix typical of hyaline cartilage. Cartilage defects larger than 1 cm2 change articular biomechanics and lead to eventual osteoarthritis and joint destruction. During the past decade, several competing techniques have evolved to stimulate articular cartilage repair. Small lesions can be successfully treated by either micro-fracture or osteochondral cylinder grafting. The latter technique allows immediate weight bearing but leads to damage of previously uninvolved areas of articular cartilage, which limits its application to lesions of less than 2 cm2. When the damaged area is more extensive, grafting of autologous chondrocytes should be considered. First a diagnostic arthroscopy is performed to assess the damaged area and a small cartilage biopsy is taken. 6 weeks later, arthrotomy and chondrocyte transplantation are performed. In the interval, the antologous chondrocytes have expanded by 2 to 3 orders of magnitude. Our experience to date includes 10 cases with follow-up of 6 months to 5 years. Preoperative complaints of crepitation and locking disappear. There is functional improvement and pain reduction of approximately 50%. This procedure, currently limited to patients under 55 years of age with limited damage to an articular surface, for the first time allows reconstruction of damaged articular areas without resorting to allografts.