Arthroscopic osteochondral autograft transplantation in anterior cruciate ligament reconstruction: a preliminary clinical study

Surgical options for articular defects of the knee

Cartilage and osteochondral defects of the knee can in most cases be treated with total knee replacement in the elderly population. However, these lesions pose a difficult treatment problem in the younger patient. A number of surgical options are available today to address this increasingly common condition and each has its own indications and limitations. This article reviews debridement and microfracture, fixation, metallic spacing devices, autologous chondrocyte implantation, osteochondral autograft transplantation, fresh cadaveric allografts and osteotomies. In addition, possible future developments are discussed.

Results at 10 to 14 years after osteochondral autografting (mosaicplasty) in articular cartilage defects in the knee

PURPOSE

The aim of this study was to evaluate the medium-term (5-9 years) and long-term (10-14 years) outcomes of mosaicplasty in the knee and identify possible risk factors for poor outcome.

METHODS

We included patients 60 years or younger with symptomatic focal full-thickness chondral lesions. Seventy-three patients (87%) with median age of 34 years were available for analyses. Clinical outcome was evaluated by Lysholm score and VAS of pain.

RESULTS

Both the mean Lysholm score and mean VAS pain score improved significantly from baseline, 49 (SD 17) and 58 (SD 23), respectively, to both the mid-term follow-up, 72 (SD18, p<0.001) and 27 (SD 20, p<0.001), respectively, and the long-term follow-up, 72 (SD 21, p<0.001) and 33 (SD 23, p<0.001), respectively. A poor outcome at the long-term follow-up - defined as a Lysholm score of 64 or less or having had a knee replacement - was found in 40%. A poor outcome was more frequent in patients 40 years or older (59%), in women (61%) and in defects with an area of 3 cm(2) or more (57%). Conversely, in a subgroup of male individuals younger than 40 years with defect size less than 3 cm(2) the failure rate was 12.5% and the mean Lysholm score was 82 (SD 16).

CONCLUSION

We conclude that the long-term clinical outcome after mosaicplasty varies greatly depending on age, gender and the size of the lesion.

LEVEL OF EVIDENCE

IV-Retrospective Case Series.

Results of microfracture in the osteoarthritic knee with focal full-thickness articular cartilage defects and concomitant medial meniscal tears

Purpose

To evaluate the efficacy of arthroscopic microfracture in patients with focal full-thickness cartilage defects in the osteoarthritic knee.

Materials and Methods

Seventy-six patients were enrolled in this study. They were divided into group I (n=38) who underwent microfracture plus meniscectomy and group II (n=38) who underwent only meniscectomy. Clinical and radiological evaluations were performed.

Results

At the time of the three-year follow-up, a total of five failures (6.6%) were reported: four patients in group I and one in group II. The two groups showed no significant difference in the Lysholm score, the Tegner activity score and the visual analog pain scale score at three years after surgery. However, at the time of the three-month follow-up, group II showed significantly more improvement in the Tegner activity and the visual analog pain score compared with group I.

Conclusions

In the osteoarthritic knee, additional microfracture did not confer any additional benefit to meniscectomy.

Microscale surface friction of articular cartilage in early osteoarthritis

Articular cartilage forms the articulating surface of long bones and facilitates energy dissipation upon loading as well as joint lubrication and wear resistance. In normal cartilage, boundary lubrication between thin films at the cartilage surface reduces friction in the absence of interstitial fluid pressurization and fluid film lubrication by synovial fluid. Inadequate boundary lubrication is associated with degenerative joint conditions such as osteoarthritis (OA), but relations between OA and surface friction, lubrication and wear in boundary lubrication are not well defined. The purpose of the present study was to measure microscale boundary mode friction of the articular cartilage surface in an in vivo experimental model to better understand changes in cartilage surface friction in early OA. Cartilage friction was measured on the articular surface by atomic force microscopy (AFM) under applied loads ranging from 0.5 to 5 μN. Microscale AFM friction analyses revealed depth dependent changes within the top-most few microns of the cartilage surface in this model of early OA. A significant increase of nearly 50% was observed in the mean engineering friction coefficient for OA cartilage at the 0.5 μN load level; no significant differences in friction coefficients were found under higher applied loads. Changes in cartilage surface morphology observed by scanning electron microscopy included cracking and roughening of the surface indicative of disruption and wear accompanied by an apparent disintegration of the thin surface lamina from the underlying matrix. Immunohistochemical staining of lubricin - an important cartilage surface boundary lubricant - did not reveal differences in spatial distribution near the cartilage surface in OA compared to controls. The increase in friction at the 0.5 μN force level is interpreted to reflect changes in the interfacial mechanics of the thin surface lamina of articular cartilage: increased friction implies reduced lubrication efficiency and a higher potential for cartilage surface wear in OA. The effects of mechanical or biochemical changes or loss of the thin surface lamina on the remaining tissue with respect to OA progression is unknown and requires further study, but preservation of the surface lamina seems an important early target for the maintenance of cartilage health and prevention of OA.

Fresh osteochondral allograft is a suitable alternative for wide cartilage defect in the knee

INTRODUCTION

There are several surgical options to restore a wide osteochondral defect in the knee. Fresh osteochondral allografts are usually considered a poor alternative due to their difficulties in surgical application. The aim of this work is first to present our experience including the surgical technique and the functional results of patients receiving fresh osteochondral allograft to restore major knee lesions, then, to compare our results with other results presented in literature.

METHODS

Between 2006 and 2011, we treated 11 patients with osteochondral lesion of the knee (Outerbridge IV°). The average lesion size was 10.3 cm(2) (range 3-20 cm(2)). The average age was 34 years (range 18-66). Patients were followed from 12 to 55 months (average of 26.5) through clinical examination, X-ray film and MRI every 3 months for the first year, then every 6 months.

RESULTS

The treatment was successful in 10 patients showing pain regression and mean IKDC subjective score improvements from 27.3 to 58.7. The IKDC objective score also improved of at least one class for each patient except the who failed. The radiographs show good osteointegration in all cases but one.

CONCLUSIONS

Fresh allograft is an effective therapy for osteochondral defects repair because it allows functional recovery in a considerable number of patients. This technique obtains better results in lesion smaller than 8 cm(2). However larger lesion show good results.

LEVEL OF EVIDENCE

Therapeutic study, Level IV.

Arthroscopic mosaicplasty for osteochondral lesions of the knee: computer-assisted navigation versus freehand technique

PURPOSE

The purpose of this study was to compare a freehand arthroscopic approach versus mosaicplasty for treatment of osteochondral lesions of the knee with a navigated arthroscopic technique.

METHODS

Four whole cadaveric lower limbs were used. A conventional navigation system was used in combination with an autologous osteochondral graft transplantation system (Osteochondral Autograft Transfer System [OATS]; Arthrex, Naples, FL). The congruity of the articular surface was measured with the navigation probe to detect any difference between the surface created by the grafts and the surface of the femoral condyle surrounding them. The angle relates to a line perpendicular to the articular surface. This line is made by the cutting instrument for graft harvesting and insertion and the articular surface.

RESULTS

The mean angle of graft harvest was 3.4° (range, 0° to 10°) in the navigated group versus 14.8° (range, 6° to 26°) in the freehand group (P < .0003). The mean angle for recipient-site coring was 1.5° (range, 0° to 5°) in the navigated group versus 12.6° (range, 4° to 17°) in the freehand group (P < .0003). The mean angle of graft placement was 2° (range, 1° to 5°) in the navigated group versus 10.8° (range, 5° to 15°) in the freehand group (P = .0002). The mean protrusion height of the plug was 0.23 mm (range, 0.1 to 0.5 mm; SD, 0.16) in the navigated group versus 0.34 mm (range, 0.0 to 0.7 mm; SD, 0.25) in the freehand group (P = .336).

CONCLUSIONS

Computer-assisted arthroscopic mosaicplasty for treatment of osteochondral lesions in the cadaveric model presented in this study allows permanent visualization of the angle of recipient-site preparation, the depth of the donor plug and the recipient plug, and the angle of insertion of the graft at the recipient site.

CLINICAL RELEVANCE

This study shows evidence of potentially greater precision and reproducibility of navigated arthroscopic mosaicplasty when compared with an arthroscopic freehand technique in a cadaveric model. However, true clinical outcome benefit will only be elucidated upon performance of appropriate clinical studies.

Cartilage lesions in patellofemoral dislocations: incidents/locations/when to treat

Patellofemoral (PF) dislocations are frequently associated with chondral injury. Chondral and osteochondral lesions are often associated with traumatic (high-energy) PF dislocations, whereas atraumatic (low-energy) PF dislocations in patients with significant PF risk factors have a much lower incidence of osteochondral damage. This article provides a historical overview and delineates the current state of radiographic and clinical outcomes of osteochondral lesions after PF dislocation. The importance of understanding risk factors of redislocation is emphasized, and the current treatment options for these cartilage lesions associated with PF dislocation are briefly summarized.

Cylindrical costal osteochondral autograft for reconstruction of large defects of the capitellum due to osteochondritis dissecans

BACKGROUND

There is a need to clarify the usefulness of and problems associated with cylindrical costal osteochondral autograft for reconstruction of large defects of the capitellum due to osteochondritis dissecans.

METHODS

Twenty-six patients with advanced osteochondritis dissecans of the humeral capitellum were treated with use of cylindrical costal osteochondral autograft. All were males with elbow pain and full-thickness articular cartilage lesions of ≥15 mm in diameter. Clinical, radiographic, and magnetic resonance imaging outcomes were evaluated at a mean follow-up of thirty-six months (range, twenty-four to fifty-one months).

RESULTS

All patients had rapid functional improvement after treatment with costal osteochondral autograft and returned to their former activities, including sports. Five patients needed additional minor surgical procedures, including screw removal, loose body removal, and shaving of protruded articular cartilage. Mean elbow function, assessed with use of the clinical rating system of Timmerman and Andrews, was 111 points preoperatively and improved to 180 points at the time of follow-up and to 190 points after the five patients underwent the additional operations. Mean elbow motion was 126° of flexion with 16° of extension loss preoperatively and improved to 133° of flexion with 3° of extension loss at the time of follow-up. Osseous union of the graft on radiographs was obtained within three months in all patients. Revascularization of the graft depicted on T1-weighted magnetic resonance imaging and congruity of the reconstructed articular surface depicted on T2-weighted or short tau inversion recovery imaging were assessed at twelve and twenty-four months postoperatively. Functional recovery was good, and all patients were satisfied with the final outcomes.

CONCLUSIONS

Cylindrical costal osteochondral autograft was useful for the treatment of advanced osteochondritis dissecans of the humeral capitellum. Functional recovery was rapid after surgery. Additional operations were performed for five of the twenty-six patients, whereas the remaining patients showed essentially full recovery within a year. All patients were satisfied with the results at the time of short-term follow-up.

Augmenting the articular cartilage-implant interface: Functionalizing with a collagen adhesion protein

The lack of integration between implants and articular cartilage is an unsolved problem that negatively impacts the development of treatments for focal cartilage defects. Many approaches attempt to increase the number of matrix-producing cells that can migrate to the interface, which may help to reinforce the boundary over time but does not address the problems associated with an initially unstable interface. The objective of this study was to develop a bioadhesive implant to create an immediate bond with the extracellular matrix components of articular cartilage. We hypothesized that implant-bound collagen adhesion protein (CNA) would increase the interfacial strength between a poly(vinly alcohol) implant and an articular cartilage immediately after implantation, without preventing cell migration into the implant. By way of a series of in vitro immunohistochemical and mechanical experiments, we demonstrated that (i) free CNA can bind to articular cartilage, (ii) implant-bound CNA can bind to collagen type II and (iii) implants functionalized with CNA result in a fourfold increase in interfacial strength with cartilage relative to untreated implants at day zero. Of note, the interfacial strength significantly decreased after 21 days in culture, which may be an indication that the protein itself has lost its effectiveness. Our data suggest that functionalizing scaffolds with CNA may be a viable approach toward creating an initially stable interface between scaffolds and articular cartilage. Further efforts are required to ensure long-term interface stability.

OSTEOCHONDRAL AUTOLOGOUS TRANSPLANTATION FOR TREATING CHONDRAL LESIONS IN THE PATELLA

Objective: The primary aim of this study was to assess the clinical and functional evolution of patients with total-thickness symptomatic cartilaginous injury of the patellar joint surface, treated by means of osteochondral autologous transplantation. Methods: This prospective study was conducted from June 2008 to March 2011 and involved 17 patients. The specific questionnaires of Lysholm, Kujala and Fulkerson were completed preoperatively and one year postoperatively in order to assess the affected knee, and SF-36 was used to assess these patients’ general quality of life. The nonparametric paired Wilcoxon test was used for statistical analysis on the pre and postoperative questionnaires. The data were analyzed using the SPSS for Windows software, version 16.0, and a significance level of 5% was used. Results: The Lysholm preoperative and postoperative average scores were 54.59 and 75.76 points (p < 0.05). The Fulkerson pre and postoperative average scores were 52.53 and 78.41 points (p < 0.05). Conclusions: We believe that autologous osteochondral transplantation is a good treatment method for total-thickness symptomatic chondral lesions of the joint surface of the patella.

Osteochondral Autograft and Mosaicplasty in the Football (Soccer) Athlete

OBJECTIVE

To evaluate the clinical outcomes of mosaicplasty in the treatment of focal chondral and osteochondral defects of joints among elite football players.

METHODS

Case series; Level of evidence, 4. The results of mosaicplasty were prospectively evaluated with 1-year intervals with patient-reported outcome measures, radiographs, and sports participation.

RESULTS

Sixty-one patients who received mosaicplasty in the knee joint were followed from 2 to 17 years (average, 9.6 years). The International Cartilage Repair Society (ICRS) score showed 89% good and excellent results. Sixty-seven percent of all players returned to the same level of sport, with 89% of the elite players and 62% of the competitive players. The average time to return to competitions was 4.5 months (range, 3.5-6.1 months). Players who had better clinical outcomes were significantly younger and had smaller lesions. The results of the medial and lateral condyles were significantly better than those in the patella or trochlea. Concomitant adjuvant procedures improved clinical outcomes. Despite a higher rate of preoperative osteoarthritic changes, clinical outcomes demonstrated a success rate similar to that of less athletic patients.

CONCLUSION

Autologous osteochondral mosaicplasty in competitive football players is a good alternative procedure to repair cartilage damage.

Scientific Evidence Base for Cartilage Injury and Repair in the Athlete

Soccer players and athletes in high-impact sports are frequently affected by knee injuries. Injuries to the anterior cruciate ligament and menisci are frequently observed in soccer players and may increase the risk of developing an articular cartilage lesion. In high-level athletes, the overall prevalence of knee articular cartilage lesions has been reported to be 36% to 38%. The treatment for athletic patients with articular cartilage lesions is often challenging because of the high demands placed on the repair tissue by impact sports. Cartilage defects in athletes can be treated with microfracture, osteochondral grafting, and autologous chondrocyte implantation. There is increasing scientific evidence for cartilage repair in athletes, with more extensive information available for microfracture and autologous chondrocyte implantation than for osteochondral grafting. The reported rates and times to return to sport at the preinjury level are variable in recreational players, with the best results seen in younger and high-level athletes. Better return to sport is consistently observed for all repair techniques with early cartilage repair. Besides minimizing sensorimotor deficits and addressing accompanying pathologies, the quality of the repair tissue may be a significant factor for the return to sport.

Effectiveness and limitations of autologous osteochondral grafting for the treatment of articular cartilage defects in the knee

PURPOSE

To evaluate the effectiveness and limitations of autologous osteochondral grafting for the treatment of articular cartilage defects in the knee.

METHODS

The subjects were 40 patients who had undergone autologous osteochondral grafting. Fifteen knees had cartilage defects combined with anterior cruciate ligament tears (ACL group), 15 knees had cartilage defects combined with osteoarthritis (OA group), and 10 knees had cartilage defects combined with osteochondral dissecans (OCD group). From one to five osteochondral pegs were harvested from the less-weight-bearing periphery of the articular surface of the femoral condyle and grafted to cartilage defects. The clinical results were assessed based on the Lysholm score and radiographic and magnetic resonance imaging (MRI) image assessment.

RESULTS

The median follow-up duration was 24 months (range from 12 to 41 months). The mean Lysholm score following treatment was improved in all groups. The patients who had cartilage defects combined with OA had a significantly poorer prognosis than did those with cartilage defects combined with ACL or OCD. In the OA group, advanced stage and an alignment abnormality were correlated with poor prognosis. Advanced age was correlated with poor prognosis. Other parameters showed no significant difference in prognosis.

CONCLUSION

Autologous osteochondral grafting was found to be an effective technique for treating relatively young patients who had cartilage defects combined with ACL injury or OCD, but this technique showed limited results in treating cartilage defects based on advanced patient age and degenerative changes in the cartilage.

LEVEL OF EVIDENCE

Diagnostic studies-investigating a diagnostic test, Level III.

Anterior cruciate ligament deficiency leads to early instability of scaffold for cartilage regeneration: a controlled laboratory ex-vivo study

PURPOSE

The affect of anterior cruciate ligament (ACL) integrity on the early postoperative stability of a collagen type-I gel scaffold was investigated. The value of fibrin glue for graft fixation in ACL deficient porcine knees over a simulated early postoperative period was also studied.

METHODS

Full-thickness articular cartilage defects (11 × 6 mm) were created on the medial femoral condyle of 80 porcine knees. The ACL was left intact or completely transected in each of 40 knees. Gel plugs were tested in each group: press-fitting only in 20 specimens and press-fitting plus fibrin glue in 20 specimens. Each knee underwent 2,000 cycles in a validated ex-vivo continuous passive motion model.

RESULTS

Press-fit-only fixation grafts in knee specimens with an intact ACL showed significantly superior stability than that in ACL deficient knees (p = 0.01). In ACL deficient knees, grafts fixed with press-fitting plus fibrin glue showed significantly superior stability than those using press-fit only fixation (p = 0.01). Press-fitting plus fibrin glue fixation showed no significant differences in worn surface area between knee specimens with intact and deficient ACL.

CONCLUSIONS

ACL deficiency led to early scaffold instability in an ex-vivo porcine knee model. Fibrin glue in ACL deficient knees led to additional graft stability. These findings indicated that cartilage regenerative techniques may give optimum results in ACL intact knees.

MR imaging assessment of articular cartilage repair procedures

Because articular cartilage is avascular and has no intrinsic capacity to heal itself, physical damage to cartilage poses a serious clinical problem for orthopedic surgeons and rheumatologists. No medication exists to treat or reconstitute physical defects in articular cartilage, and pharmacotherapy is limited to pain control. Developments in the field of articular cartilage repair include microfracture, osteochondral autografting, osteochondral allografting, repair with synthetic resorbable plugs, and autologous chondrocyte implantation. MR imaging techniques have the potential to allow in vivo monitoring of the collagen and proteoglycan content of cartilage repair tissue and may provide useful additional metrics of cartilage repair tissue quality.

Fresh osteochondral allograft for the treatment of cartilage defects of the talus: a retrospective review

BACKGROUND

Osteochondral lesions of the talar dome can cause substantial functional impairment and present a difficult treatment dilemma. Interest has recently focused on fresh osteochondral allografts as a promising treatment alternative. The purpose of this study was to evaluate the clinical outcome of osteochondral lesions of the talus treated with a fresh osteochondral allograft.

METHODS

We performed a transfer of fresh osteochondral allograft in forty-two patients with a symptomatic, refractory osteochondral lesion of the talus. Complete postoperative follow-up was achieved for thirty-eight patients with an average age of 44.2 years. Clinical evaluation was performed with use of the American Orthopaedic Foot & Ankle Society ankle-hindfoot score and a visual analog pain scale. All scores were obtained from either a retrospective chart review or a direct patient interview. All patients were also asked about their subjective satisfaction with the procedure. Magnetic resonance images were acquired for fifteen patients, to assess graft incorporation, subsidence, articular cartilage congruity, osteoarthritis, and stability with use of the De Smet criteria.

RESULTS

The average duration of follow-up after osteochondral allograft transplantation was 37.7 months. Graft failure occurred in four patients. With the inclusion of scores before revision for those with graft failure, the mean visual analog pain scale score improved from 8.2 to 3.3 points, and the mean American Orthopaedic Foot & Ankle Society ankle-hindfoot score improved from 52 to 79 points. Patient satisfaction with the outcome was rated as excellent, very good, or good by twenty-eight of the thirty-eight patients and as fair or poor by ten patients. Of the fifteen magnetic resonance imaging scans, most showed minimal graft subsidence, reasonable graft stability, and persistent articular congruence.

CONCLUSIONS

In our experience, transplantation of fresh osteochondral allograft is a viable and effective method for the treatment of osteochondral lesions of the talus as evidenced by improvements in pain and function.

Influence of hepatocyte growth factor on autologous osteochondral transplants in an animal model

PURPOSE

Several studies have investigated the influence of different growth factors on hyaline cartilage regeneration. In a rabbit model, hepatocyte growth factor (HGF) was proven to increase the amount of hyaline-like chondrocytes in a mixed fibro-cartilaginous regenerate of small defects. The aim of the current study was to evaluate whether intra-articular administration of HGF influences the ingrowth of osteochondral grafts in a sheep model.

TYPE OF STUDY

Animal experiment.

METHODS

Both knee joints of eight sheep were opened surgically and osteochondral grafts were harvested and simultaneously transplanted to the opposite condyle of the same joint. The sheep were divided into two groups of four sheep, resulting in 16 grafts per group. In one group, HGF was administered by bilateral intra-articular injections given three times a week for 4 weeks. The control group received isotonic sodium chloride injections. The animals were killed after 3 months.

RESULTS

Histological evaluation showed a complete ingrowth of the osseous part of the osteochondral grafts. A healing or ingrowth at the level of the cartilage could not be observed. Histological evaluation of the transplanted grafts according to the modified Mankin score revealed less degeneration in the cartilage of the HGF group, as compared to the control group. In the HGF group, less cloning of chondrocytes and less irregularities of the articular surface were observed. Importantly, no deleterious effects, such as osteophyte formation, cartilage thickening or synovial proliferation, were found.

CONCLUSION

HGF positively influenced the cellularity of the transplanted osteochondral graft, but could not diminish the fissures in the marginal zone of the grafts.

CLINICAL RELEVANCE

Marginal zone fissures and degeneration in the absence of HGF may undermine long-term results of autologous osteochondral grafts.

Direct delayed human adenoviral BMP-2 or BMP-6 gene therapy for bone and cartilage regeneration in a pony osteochondral model

OBJECTIVE

To evaluate healing of surgically created large osteochondral defects in a weight-bearing femoral condyle in response to delayed percutaneous direct injection of adenoviral (Ad) vectors containing coding regions for either human bone morphogenetic proteins 2 (BMP-2) or -6.

METHODS

Four 13mm diameter and 7mm depth circular osteochondral defects were drilled, 1/femoral condyle (n=20 defects in five ponies). At 2 weeks, Ad-BMP-2, Ad-BMP-6, Ad-green fluorescent protein (GFP), or saline was percutaneously injected into the central drill hole of the defect. Quantitative magnetic resonance imaging (qMRI) and computed tomography (CT) were serially performed at 12, 24, and 52 weeks. At 12 (one pony) or 52 weeks, histomorphometry and microtomographic analyses were performed to assess subchondral bone and cartilage repair tissue quality.

RESULTS

Direct delivery of Ad-BMP-6 demonstrated delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) and histologic evidence of greater Glycosaminoglycan (GAG) content in repair tissue at 12 weeks, while Ad-BMP-2 had greater non-mineral cartilage at the surface at 52 weeks (p<0.04). Ad-BMP-2 demonstrated greater CT subchondral bone mineral density (BMD) by 12 weeks and both Ad-BMP-2 and -6 had greater subchondral BMD at 52 weeks (p<0.05). Despite earlier (Ad-BMP-6) and more persistent (Ad-BMP-2) chondral tissue and greater subchondral bone density (Ad-BMP-2 and -6), the tissue within the large weight-bearing defects at 52 weeks was suboptimal in all groups due to poor quality repair cartilage, central fibrocartilage retention, and central bone cavitation. Delivery of either BMP by this method had greater frequency of subchondral bone cystic formation (p<0.05).

CONCLUSIONS

Delivery of Ad-BMP-2 or Ad-BMP-6 via direct injection supported cartilage and subchondral bone regeneration but was insufficient to provide long-term quality osteochondral repair.

Chondral repair of the knee joint using mosaicplasty

Mosaicplasty grafting is performed by transferring one or more cylindral osteochondral autografts from a low weight-bearing area of the knee towards the defective site, usually the femoral condyle. Numerous biomechanical, histological, animal and clinical studies have evaluated the different technical aspects of this procedure. The preoperative work-up encompasses an evaluation of functional disturbances, alignment, knee stability and imaging (CT arthrography or MRI with cartilage sequences). The surgical procedure includes harvesting the grafts by mini-arthrotomy of the medial or lateral trochlea and a stage for arthroscopic graft insertion. The ICRS classification is used to describe the defect (area, depth, location) before and then after debridement. A few, large diameter grafts are harvested from the trochlea across from the defect. The graft plugs are transplanted by press-fit, flush with the cartilage, along a convergent plane in recipient sockets of exactly the same depth. Each stage, harvesting, drilling and insertion is repeated until all the full-thickness gap region has been covered. Postoperative movement is free but weight-bearing is delayed for 2 to 4 weeks. Mosaicplasty is indicated in young patients (under 50), with symptomatic chondral or osteochondral defects of less than 3 cm in the weight-bearing part of the femoral condyle. Pre-osteoarthritis is an absolute contraindictation for this procedure. Any misalignment (of more than 5°) or sagittal instability is treated simultaneously. This is a difficult and demanding procedure.

Effects of a surface matching articular resurfacing device on tibiofemoral contact pressure: results from continuous dynamic flexion-extension cycles

INTRODUCTION

The application of a defect-size metal implant for the treatment of focal articular cartilage lesions of the femoral condyle is of potential concern resulting in cartilage damage to opposing biological structures. This in vitro study aims to determine the tibiofemoral contact pressure with a contoured articular partial femoral resurfacing device under continuous dynamic pressure loads.

METHODS

Peak and area contact pressures were determined in eight fresh-frozen cadaveric specimens using a pressure-sensitive sensor placed in the medial compartment above the menisci. All knees were tested in the untreated condition and after implantation of the prosthetic device in the weight-bearing area of the medial femoral condyle. A robotic knee simulator was used to test each knee under continuous pressure load for 400 s during 40 dynamic knee bending cycles (5°-45° flexion) with body weight ground reaction force (GRF). The GRF was adjusted to the living body weight of the cadaver donor and maintained throughout all cycles.

RESULTS

Comparison of the untreated condition to focal inlay resurfacing showed no statistically significant differences (P ≤ 0.05) between all testing conditions. The average maximum peak contact pressure across all 40 flexion cycles increased by 5.1% after resurfacing compared to the untreated knees. The average area contact pressure essentially stayed the same (+0.9%).

CONCLUSION

The data suggest that resurfacing with the contoured articular prosthetic device does not pose any immediate deleterious effects to the opposing surfaces based on peak and area contact pressure in a continuous dynamic in vitro application. However, long-term in vivo effects remain to be evaluated.

Articular cartilage tissue engineering based on a mechano-active scaffold made of poly(L-lactide-co-epsilon-caprolactone): In vivo performance in adult rabbits

Our previous studies showed that a mechano-active scaffold made of poly(L-lactide-co-epsilon-caprolactone) (PLCL) exhibited a high potential to realize the formation of a functional, engineered cartilage in vitro. This animal study therefore was designed to investigate the feasibility of repairing on osteochondral defect with the use of bone marrow-derived mesenchymal stem cells (BMSCs) incorporated with a PLCL scaffold. Rabbit BMSCs, isolated and subsequently cultured in monolayer, were seeded into a porous PLCL scaffold sponge following an implantation onto a full-thickness osteochondral defect (diameter of 4.5 mm, depth of 5 mm) that was artificially created on the medial femoral condyles at a high load-bearing site on a rabbit's knee joint. Time-dependent healing of the defect was evaluated by macroscopic, histological examinations at both 3- and 6-month-implantations, respectively. A PLCL sponge incorporated with BMSCs exhibited sufficient structural support, resulting in new osteochondral tissue regeneration: a physiologically well-integrated subchondral bone formation, a hyaline cartilage-like morphology containing chondrocytes surrounded by abundant cartilaginous matrices. In addition, quantitative biochemical assays also demonstrated high potential for the synthesis of sulfated glycosaminoglycan and collagen, both of which are biomolecules essential to extracelluar matrix in normal cartilage tissue. In contrast, defects filled with cell-free PLCL scaffold or left empty showed a very limited potential for regeneration. Our findings suggest that a composite of PLCL-based sponge scaffold and BMSCs promote the repair of osteochondral defects at high load-bearing sites in adult rabbits.

Clinical experiences with autologous osteochondral mosaicplasty in an athletic population: a 17-year prospective multicenter study

BACKGROUND

Several methods are used to treat focal chondral and osteochondral defects on the weightbearing surfaces of synovial joints. Autologous osteochondral grafting is 1 option used to replace hyaline cartilage in the defect.

HYPOTHESIS

Mosaicplasty is effective in returning elite athletes to participation in sports.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

In 3 institutes, 354 of 383 patients were followed from 2 to 17 years (average, 9.6 years). The results of mosaicplasty were prospectively evaluated at 6 weeks, 3 months, 6 months, and yearly with patient-reported outcomes measures and radiographs.

RESULTS

Slight or moderate degenerative changes (Fairbank grade I or II) were detected preoperatively in 27% of the cases and in 36% of the cases at follow-up. Fairbank grade III changes were observed in 5 cases. An average radiographic deterioration of 0.32 on the Fairbank scale was detected (preoperative, 0.34; postoperative, 0.66). Good to excellent results were found in 91% of femoral mosaicplasties, 86% of tibial, and 74% of patellofemoral; 92% of talar mosaicplasties had similar results (Hannover ankle scoring system). Patellofemoral pain related to graft harvest was observed in 5% of cases. Second-look arthroscopies revealed good, congruent, gliding surfaces of the transplants and acceptable fibrocartilage coverage of donor sites in 16 patients and degenerative changes of the transplants in 5 cases. Histological evaluation revealed good graft incorporation in all 11 cases. Two infections and 3 deep venous thromboses occurred.

CONCLUSION

Despite a higher rate of preoperative osteoarthritic changes in the athletic patients, clinical outcomes of mosaicplasty in this group demonstrated a success rate similar to that of less athletic patients. Higher motivation resulted in better subjective evaluation. Slight deterioration in results occurred during the 9.6-year follow-up; thus, autologous osteochondral mosaicplasty may be a useful alternative for the treatment of 1.0- to 4.0-cm(2) focal chondral and osteochondral lesions in competitive athletes.

A prospective, randomized clinical study of osteochondral autologous transplantation versus microfracture for the treatment of osteochondritis dissecans in the knee joint in children

PURPOSE

The aim of this study was to compare the outcomes of the arthroscopic mosaic-type osteochondral autologous transplantation (OAT) and microfracture (MF) procedures for the treatment of osteochondritis dissecans (OCD) defects of the femoral condyles of the knee joint in children under the age of 18 years.

TYPE OF STUDY

Prospective, randomized clinical study.

METHODS

Between 2001 and 2005, a total of 50 children with a mean age of 14.3 years (12 to 18) and with symptomatic lesions of the OCD in the femoral condyle of the knee were randomized to undergo either the OAT or the MF procedure. Only those children with grade 3 or 4 (OCD) in the medial or lateral femoral condyle (according to International Cartilage Repair Society, ICRS) were included in the study. Forty-seven patients (94%) were available for follow-up. There were 25 patients in the OAT group and 22 patients in the MF group. The mean duration of symptoms was 23.54+/-4.24 months and the mean follow-up was 4.2 years (range from 3 to 6 y), and none of the children had prior surgical interventions to the affected knee. Children were evaluated using ICRS score, x-rays, magnetic resonance imaging, and second-look arthroscopies.

RESULTS

After 1 year, both groups had significant clinical improvement (P<0.05) and the ICRS functional and objective assessment showed that 23 of 25 (92%) patients had excellent or good results after OAT compared with 19 of 22 (86%) after MF (NS), but 19 of 23 (83%) after OAT and only 12 of 19 (63%) after MF procedure maintained excellent or good results after 4.2 years (range from 3 to 6 y). The MF group showed significant deterioration over the 4.2 years follow-up (P<0.05), but still had significant clinical improvement compared with pretreatment evaluation (P=0.004). There were 9 of 22 (41%) failures in the MF group, and none in the OAT group. Magnetic resonance imaging evaluation according to the ICRS evaluation system showed excellent or good repairs in 19 of 21 patients (91%) after OAT compared with 10 of 18 (56%) after MF.

CONCLUSIONS

At an average of 4.2 years follow-up, our prospective, randomized, clinical study in children under the age of 18 years has shown significant superiority of the mosaic-type OAT over MF for the treatment of osteochondritis dissecans defects in the knee. However, our study has shown that both MF and OAT give encouraging clinical results for children under the age of 18 years.

LEVEL OF EVIDENCE

Level 1: randomized controlled trial, significant difference.

[Autologous transfer of the posterior femoral condyle for large osteochondral lesions of the knee: 5-year results of the Mega-OATS technique]

BACKGROUND

Large osteochondral defects of the weight-bearing zones of the femoral condyles in young and active patients were treated by autologous transfer of the posterior femoral condyle. This technique is a salvage procedure and aims at pain-free mobility of patients.

MATERIAL AND METHODS

Between July 1999 and December 2000, 18 patients were operated on. Sixteen patients were evaluated using the Lysholm score. X-rays were done, and eight individuals underwent magnetic resonance imaging (MRI) analysis. The average age at the date of surgery was 37.4 (15-59) years, and the mean follow-up time was 55.2 (46-62) months. The mean defect size was 5.4 cm(2) (3.1-7.1). Trauma or osteochondrosis dissecans was pathogenetic in 81%.

RESULTS

The Lysholm score showed a significant (p=0.001) increase from a preoperative median of 65.0 to a postoperative median of 86.0 points. Fifteen patients returned to sport activities. X-rays showed a rounding of the osteotomy edge in 12 patients and a partial bone-dense remodelling of the posterior femoral condyle in 11 patients. All MRI examinations showed vital and congruent grafts.

CONCLUSION

Thus, the procedure is recommended for treating large and deep focal osteochondral lesions in the weight-bearing zone of the femoral condyle.

Chondrocyte function after osteochondral transfer: comparison of concave and plane punches

BACKGROUND

An incongruity between instrument and articular surfaces in osteochondral transfer (OCT) results in unevenly distributed impact forces exerted on the cartilage which may cause a loss of functional chondrocytes. We tested whether a plane instead of a concave design of the punch of an osteotome can reduce these cartilage damages.

METHODS

Osteochondral cylinders were transferred from a donor to a recipient site within porcine humeral heads. Histological sections of the cartilage were assessed for metabolic active chondrocytes by in situ hybridization detecting coll alpha(1)(II) mRNA subsequent to OCT and 24 h thereafter.

RESULTS

The percentage of cartilage harbouring functional chondrocytes in the transferred grafts was 85 +/- 10 and 91 +/- 4% subsequently to OCT using punches with concave or plane surfaces, respectively, and 83 +/- 10% (concave) and 82 +/- 10% (plane) after 24 h. In the superficial layer of the cartilage the percentages were 72 +/- 13% (concave) and 84 +/- 8% (plane) subsequently to OCT, and 68 +/- 15% (concave) and 70 +/- 3% (plane) after 24 h. The analysis did not reveal any statistically significant differences.

CONCLUSIONS

The OCT leads to considerable loss of functional chondrocytes which could not be prevented by the use of a plane instead of a concave punch. Since functional chondrocytes might be of crucial importance for the survival and integration of the graft into the recipient site further work is needed to optimize the OCT procedure.

Anterior cruciate ligament reconstruction and concomitant articular cartilage injury: incidence and treatment

PURPOSE

Articular cartilage injuries commonly occur in conjunction with anterior cruciate ligament (ACL) injury. The exact incidence of this combined injury pattern, as well as the optimal treatment for it, has not been well studied in the literature. The purpose of this study was to systematically review the literature regarding the incidence of concomitant articular cartilage and ACL injury and the results of combined surgical treatment of these injuries.

METHODS

We performed a systematic review of studies investigating the incidence of articular cartilage injury in conjunction with ACL injury and the results of combined surgical treatment for these injuries.

RESULTS

On the basis of 5 studies in the literature, the incidence of severe articular cartilage injury in acute ACL tears is between 16% and 46%. On the basis of 3 studies on combined osteochondral autografts and ACL reconstruction and 2 studies on combined autologous chondrocyte implantation and ACL reconstruction, patients can have reasonable short-term outcomes after combined surgery.

CONCLUSIONS

Articular cartilage injury is often encountered at the time of ACL reconstruction, and combined surgery can result in reasonable outcomes. Additional studies are needed to better define both the incidence of combined injury and the outcome, particularly in the long term, after these procedures.

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 osteochondral defects in the knee joint. The authors previously reported on the histologic and radiologic outcome of autologous chondrocyte 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 cm(2) and a maximum defect area of 20 cm(2). 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.

Osteochondral allografts: state of the art

The use of osteochondral allografts to treat focal osteochondral lesions continues to gain popularity, supported by long-term results. Clinicians must be knowledgeable concerning the possible risks of disease transmission, graft rejection, infection, and graft failure to advise the patient and obtain an informed consent. With advancing scientific and clinical research, future operative indications will likely continue to expand. A significant amount of literature regarding storage methods has recently been published; it is hoped that continued research will lead to techniques for prolonged graft storage to prevent availability concerns.

Comparative study of navigated versus freehand osteochondral graft transplantation of the knee

BACKGROUND

Osteochondral lesions are a common sports-related injury for which osteochondral grafting, including mosaicplasty, is an established treatment. Computer navigation has been gaining popularity in orthopaedic surgery to improve accuracy and precision.

HYPOTHESIS

Navigation improves angle and depth matching during harvest and placement of osteochondral grafts compared with conventional freehand open technique.

STUDY DESIGN

Controlled laboratory study.

METHODS

Three cadaveric knees were used. Reference markers were attached to the femur, tibia, and donor/recipient site guides. Fifteen osteochondral grafts were harvested and inserted into recipient sites with computer navigation, and 15 similar grafts were inserted freehand. The angles of graft removal and placement as well as surface congruity (graft depth) were calculated for each surgical group.

RESULTS

The mean harvesting angle at the donor site using navigation was 4 degrees (standard deviation, 2.3 degrees ; range, 1 degrees -9 degrees ) versus 12 degrees (standard deviation, 5.5 degrees ; range, 5 degrees -24 degrees ) using freehand technique (P < .0001). The recipient plug removal angle using the navigated technique was 3.3 degrees (standard deviation, 2.1 degrees ; range, 0 degrees -9 degrees ) versus 10.7 degrees (standard deviation, 4.9 degrees ; range, 2 degrees -17 degrees ) in freehand (P < .0001). The mean navigated recipient plug placement angle was 3.6 degrees (standard deviation, 2.0 degrees ; range, 1 degrees -9 degrees ) versus 10.6 degrees (standard deviation, 4.4 degrees ; range, 3 degrees -17 degrees ) with freehand technique (P = .0001). The mean height of plug protrusion under navigation was 0.3 mm (standard deviation, 0.2 mm; range, 0-0.6 mm) versus 0.5 mm (standard deviation, 0.3 mm; range, 0.2-1.1 mm) using a freehand technique (P = .0034).

CONCLUSION

Significantly greater accuracy and precision were observed in harvesting and placement of the osteochondral grafts in the navigated procedures. Clinical studies are needed to establish a benefit in vivo.

CLINICAL RELEVANCE

Improvement in the osteochondral harvest and placement is desirable to optimize clinical outcomes. Navigation shows great potential to improve both harvest and placement precision and accuracy, thus optimizing ultimate surface congruity.

MOSAICPLASTY WITH PERIOSTEAL GRAFT FOR RESURFACING LOCAL FULL-THICKNESS CHONDRAL DEFECTS OF THE KNEE

Introduction and Objectives: Clinical and functional assessment comparing cases of full-thickness chondral defects (OC) treated with mosaicplasty or mosaicplasty covered with periosteum (mosaicambium). Methods: 20 knees with chondral defect, (10 mosaicplasty/10 mosaicambium) were operated between 1999 and 2005. All patients were clinically assessed preoperatively using the ICRS scale, VAS scale, X-ray and MRI. During 2008, we reviewed patients using the same protocol. For statistical purposes, the patients were divided into two groups, according to the surgical technique. Statistical analysis was performed with EPI2000 program, using chi-squared test and Student's t test, with a significance level of 0.05. Results: Preoperatively, all patients were in group C/D (ICRS scale). In 2008, 18 cases were in groups A and B according to the ICRS scale (12 in A). Between groups, there were no statistical differences. The X-ray study revealed no changes in 55% of cases. Discussion: With no differences, why mosaicambium option? Morbidity on graft donor zones is not negligible. Mosaicambium uses less chondral grafts, reducing the potential for morbidity at graft donor zones. Conclusion: The mosaicambium technique is an excellent alternative for chondral defects greater than 2 cm2.

“… articular cartilage defects are a troublesome thing … they don't heal …”. William Hunter (1718-1783).

Transduction of anti-cell death protein FNK suppresses graft degeneration after autologous cylindrical osteochondral transplantation

This study shows that artificial super antiapoptotic FNK protein fused with a protein transduction domain (PTD-FNK) maintains the quality of osteochondral transplant by preventing chondrocyte death. Cylindrical osteochondral grafts were obtained from enhanced green fluorescent protein (EGFP)-expressing transgenic rats, in which living chondrocytes express green fluorescence, and submerged into medium containing PTD-FNK, followed by transplantation into cartilage defects of wild-type rats by impact insertion simulating autologous transplantation. The tissues were histologically evaluated by hematoxylin-eosin and Safranin-O staining. At 1 week, chondrocyte alignment was normal in the PTD-FNK treatment group, whereas all grafts without PTD-FNK treatment showed mixed cluster cell distribution. At 4 weeks, all grafts with PTD-FNK treatment showed almost normal matrix, whereas two grafts without PTD-FNK treatment showed fibrocartilage. Notably, all grafts with PTD-FNK retained high intensity of Safranin-O staining, but all grafts without PTD-FNK largely lost Safranin-O staining. PTD-FNK significantly suppressed a decrease in the survival rate and the density of EGFP-positive cells at 1 and 2 weeks, and this tendency continued at 4 weeks. The results of terminal deoxynucleotidyl transferase (TdT)-mediated deoxyuridine triphosphate (dUTP)-nick end-labeling staining showed that PTD-FNK inhibited cell death, indicating that PTD-FNK protects chondrocyte death and suppresses graft degeneration.

The effect of low-intensity pulsed ultrasound on autologous osteochondral plugs in a canine model

BACKGROUND

Low-intensity pulsed ultrasound promotes the enchondral portion of fracture healing, which has a direct stimulatory effect on cartilage formation and maturation.

HYPOTHESIS

Daily ultrasound treatment positively affects the repair and incorporation of modified autologous osteochondral plugs in a canine model.

STUDY DESIGN

Controlled laboratory study.

METHODS

In 18 dogs, 2 autologous plugs separated from host cartilage by a 1.5-mm gap were created on the medial femoral condyle in both knees of each dog. One knee was treated daily with a clinically available ultrasound bone stimulator. Animals were sacrificed after 6 and 12 weeks of therapy and the articular surfaces evaluated grossly and histologically.

RESULTS

Ultrasound-treated sites had significantly improved gross appearance at 6 weeks and histologic appearance at 6 and 12 weeks. The interface repair tissue of ultrasound-treated sites had a more normal translucent appearance than control sites. Ultrasound treatment improved the cell morphologic characteristics of the interface repair tissue and increased subchondral bone regeneration. Bonding of the interface repair tissue between plug and adjacent cartilage was significantly improved compared with control sites.

CONCLUSION

Low-intensity pulsed ultrasound improved interface cartilage repair of autologous osteochondral plugs compared with controls in a canine model.

CLINICAL RELEVANCE

Improvements in the quality and rate of repair of autologous osteochondral plugs may reduce postoperative recovery time and improve functional outcome.

The location-specific healing response of damaged articular cartilage after ACL reconstruction: short-term follow-up

Although many different interventions have been proposed for treating cartilage lesions at the time of ACL reconstruction, the normal healing response of these injuries has not been well documented. To address this point, we compared the arthroscopic status of chondral lesions at the time of ACL reconstruction with that obtained at second-look arthroscopy. We hypothesized that there might be a location-specific difference in the healing response of damaged articular cartilage. Between September 1998 and March 2000, 383 patients underwent arthroscopically-assisted hamstring ACL reconstruction without any intervention to the articular cartilage. Among these patients, 84 patients underwent second-look arthroscopy (ranging from 6 to 52 months following initial surgery) and make up the population of the present study. Chondral injuries, left untreated at ACL reconstruction, were arthroscopically evaluated using the Outerbridge classification, and were again evaluated at second-look arthroscopy. At second-look arthroscopy, there was significant recovery of chondral lesions by Outerbridge grading on both the medial and lateral femoral condyles. Among the recovered chondral lesions, 69% of cases of the medial femoral condyle, 88% of cases of the lateral femoral condyle were partial thickness injuries (grade I and II). Conversely, there was no significant recovery of chondral lesions observed at the patello-femoral joint or tibial plateaus. Our study revealed that there was a location-specific difference in the natural healing response of chondral injury. Untreated cartilage lesions on the femoral condlyes had a superior healing response compared to those on the tibial plateaus, and in the patello-femoral joint.

The 5.5-year results of MegaOATS--autologous transfer of the posterior femoral condyle: a case-series study

INTRODUCTION

Large osteochondral defects of the weight-bearing zones of femoral condyles in young and active patients were treated by autologous transfer of the posterior femoral condyle (large osteochondral autogenous transplantation system (MegaOATS)). The technique presented is a sound and feasible salvage procedure to address large osteochondral defects in weight-bearing zones.

METHODS

Thirty-six patients between July 1996 and December 2000 were included. Thirty-three patients (10 females, 23 males) were evaluated by the Lysholm score and X-ray scans. A random sample of 16 individuals underwent magnetic resonance imaging analysis. The average age at the date of surgery was 34.3 (15 to 59) years, and the mean follow up was 66.4 (46 to 98) months. The mean defect size was 6.2 (2 to 10.5) cm2, in 27 patients affecting the medial femoral condyle and in six patients affecting the lateral femoral condyle. Trauma or osteochondrosis dissecans were pathogenetic in 82%.

RESULTS

The Lysholm score in all 33 individuals showed a highly significant increase from a preoperative median 49.0 points to a median 86.0 points (P < or = 0.001). Twenty-seven patients returned to recreational sports. X-ray scans showed a rounding of the osteotomy edge in 24 patients, interpreted as a partial remodelling of the posterior femoral condyle. Preoperative osteoarthritis in 17 individuals was related to significant lower Lysholm scores (P = 0.014), but progression in 17 patients did not significantly influence the score results (P = 0.143). All 16 magnetic resonance imaging examinations showed vital and congruent grafts.

CONCLUSION

Patients significantly improve in the Lysholm score, in daily-life activity levels and in return to recreational sports. Thirty-one out of 33 patients were comfortable with the results and would undergo the procedure again. The MegaOATS technique is therefore recommended as a salvage procedure for young individuals with large osteochondral defects in the weight-bearing zone of the femoral condyle.

Magnetic resonance imaging and clinical evaluation of patellar resurfacing with press-fit osteochondral autograft plugs

BACKGROUND

Autologous osteochondral transplantation (AOT) has been successfully used in the femoral condyle and trochlea and is an attractive treatment option for full-thickness patellar cartilage lesions.

HYPOTHESIS

Patients treated with AOT for the repair of symptomatic, isolated patellar cartilage lesions will demonstrate improvement in functional outcomes and postoperative magnetic resonance imaging appearance.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Between 2002 and 2006, patients with focal patellar cartilage lesions treated with AOT were prospectively followed. The mean age at the time of surgery was 30 years. Clinical assessment was performed with the International Knee Documentation Committee (IKDC), activities of daily living of the Knee Outcome Survey (ADL), and Short Form-36 (SF-36) at baseline and most recent follow-up. Magnetic resonance imaging was used to evaluate the cartilage repair morphologic characteristics in 14 cases.

RESULTS

Twenty-two patients met the study criteria with a mean follow-up of 28.7 months (range, 17.7-57.8 months). The mean patellar lesion size was 165.6 +/- 127.8 mm(2), and the mean size of the donor plug was 9.7 +/- 1.1 mm in diameter with 1.8 +/- 1.4 plugs/defect. The mean preoperative IKDC score was 47.2 +/- 14.0 and improved to 74.4 +/- 12.3 (P = .028). The mean preoperative ADL score was 60.1 +/- 16.9 and increased to 84.7 +/- 8.3 (P = .022). The mean SF-36 also demonstrated an improvement, from 64.0 +/- 14.8 at baseline to 79.4 +/- 15.4 (P = .059). Nine patients underwent concomitant distal realignment and demonstrated improvement between preoperative and postoperative outcomes scores, but these differences were not statistically significant. Magnetic resonance imaging appearance demonstrated that all plugs demonstrated good (67%-100%) cartilage fill, 64% with fissures < 2 mm at the articular cartilage interface, 71% with complete trabecular incorporation, and 71% with flush plug appearance.

CONCLUSION

Patellar AOT is an effective treatment for focal patellar chondral lesions, with significant improvement in clinical follow-up. This study suggests that patients with patellar malalignment may represent a subset of patients who have a poor prognostic outlook compared with patients with normal alignment.

Autologous osteochondral grafting--technique and long-term results

BACKGROUND

Efficacious treatment of chondral and osteochondral defects of weightbearing articular surfaces is a daily challenge in musculoskeletal care. Autogenous osteochondral transplantation represents a possible solution for creating hyaline or hyaline-like repair in the affected area that has a noninflammatory pathoorigin. This paper discusses the experimental background and over 15 years of clinical experience with autologous osteochondral mosaicplasty.

METHODS

Several series of animal studies and subsequent clinical practice of over 1,000 mosaicplasty patients were assessed to confirm the survival of transplanted hyaline cartilage and fibrocartilage filling of donor sites located on relatively less weightbearing surfaces, as well as donor-site disturbances and morbidity. Histological evaluations of dog and horse implantations as well as several series of clinical evaluations in the human material are summarized in this paper. Clinical scores, different types of imaging techniques, second-look arthroscopies, histological examination of biopsy samples, and cartilage stiffness measurements were used to evaluate the clinical outcomes and quality of the transplanted cartilage.

RESULTS

Analysis of clinical scores has shown good to excellent results in 92% of patients with femoral condylar implantations, 87% of tibial resurfacements, 74% of patellar and/or trochlear mosaicplasties and 93% of talar procedures. Longterm donor-site complaints measured by the Bandi score were minor and present only in 3% of patients. 81 out of the 98 control arthroscopies represented congruent and good gliding surfaces and histologically proven survival of the transplanted hyaline cartilage as well as fibrocartilage covering of the donor sites. Complications in the entire patient group were four deep infections and four deep venous thromboses. In nearly 8% of the cases excessive intraarticular bleeding was observed in the early postoperative period, as a minor complication of the procedure. Multicentric, comparative, prospective evaluation of 413 arthroscopic resurfacing procedures (mosaicplasty, Pridie drilling, abrasion arthroplasty and microfracture cases in homogenised subgroups) demonstrated that mosaicplasty resulted in favourable clinical outcome in the long-term follow-up compared to other three techniques. Durability of the early results was confirmed in long-term evaluations both of the femoral condylar implantations and talar mosaicplasties.

CONCLUSIONS

According to our encouraging results in this increasingly large series, supported by similar findings from other centres, it seems that autologous osteochondral mosaicplasty may be an alternative for small and medium-sized focal chondral and osteochondral defects of weightbearing surfaces of the knee and other weightbearing synovial joints.

Treatment of focal articular cartilage defects in the knee: a systematic review

We asked whether autologous chondrocyte implantation or osteochondral autograft transfer yields better clinical outcomes compared with one another or with traditional abrasive techniques for treatment of isolated articular cartilage defects and whether lesion size influences this clinical outcome. We performed a literature search and identified five randomized, controlled trials and one prospective comparative trial evaluating these treatment techniques in 421 patients. The operative procedures included autologous chondrocyte implantation, osteochondral autograft transfer, matrix-induced autologous chondrocyte implantation, and microfracture. Minimum followup was 1 year (mean, 1.7 years; range, 1-3 years). All studies documented greater than 95% followup for clinical outcome measures. No technique consistently had superior results compared with the others. Outcomes for microfracture tended to be worse in larger lesions. All studies reported improvement in clinical outcome measures in all treatment groups when compared with preoperative assessment; however, no control (nonoperative) groups were used in any of the studies. A large prospective trial investigating these techniques with the addition of a control group would be the best way to definitively address the clinical questions.

LEVEL OF EVIDENCE

Level II, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Biochemical, biomechanical and histological properties of osteoarthritic porcine knee cartilage: implications for osteochondral transplantation

INTRODUCTION

Cartilage lesions of the knee joint are frequently observed during arthroscopy and when surgical intervention is required, osteochondral autograft procedures are an established method of treatment. Frequently lesions are located on the medial femoral condyle (MFC), and typical donor locations for osteochondral grafts include the medial and lateral patellar groove. This technique provides good results, even when the quality of cartilage transplanted from an osteoarthritic joint is doubtful. This study characterizes biological, biomechanical and histological properties of cartilage explants from the patellar groove harvested from osteoarthritic joints.

MATERIALS AND METHODS

Cylindrical cartilage explants were harvested from the arthritic areas of the MFC as well as normal appearing regions of the medial and lateral patellar groove from porcine joints revealing various grades of osteoarthritis. Matrix synthesis rates were determined, and explants were investigated by mechanical testing and histology.

RESULTS

Articular cartilage obtained from the typical donor areas of the medial and lateral patellar groove provided constant enhanced material properties, matrix synthesis rates and histological appearance compared to samples from the arthritic lesions of the MFC, even in joints with end-stage osteoarthritis of the MFC. No significant difference was found between patellar groove cartilage samples harvested from joints with different stages of osteoarthritis.

CONCLUSION

Our findings demonstrate that healthy appearing cartilage from the patellar groove does not undergo significant alterations in material properties due to the arthritic milieu present in osteoarthritic joints. Accordingly these locations provide a source of functional tissue for transplant procedures even in joints with end-stage osteoarthritis.