Arthroscopic autogenous osteochondral transplantation for treating knee cartilage defects: a 2- to 5-year follow-up study

Isolated Osteochondral Autograft Versus Allograft Transplantation for the Treatment of Symptomatic Cartilage Lesions of the Knee: A Systematic Review and Meta-analysis

BACKGROUND

Focal cartilage lesions of the knee remain a difficult entity to treat. Current treatment options include arthroscopic debridement, microfracture, autograft or allograft osteochondral transplantation, and cell-based therapies such as autologous chondrocyte transplantation. Osteochondral transplantation techniques restore the normal topography of the condyles and provide mature hyaline cartilage in a single-stage procedure. However, clinical outcomes comparing autograft versus allograft techniques are scarce.

PURPOSE

To perform a comprehensive systematic review and meta-analysis of high-quality studies to evaluate the results of osteochondral autograft and allograft transplantation for the treatment of symptomatic cartilage defects of the knee.

STUDY DESIGN

Systematic review and meta-analysis; Level of evidence, 2.

METHODS

A comprehensive search of the literature was conducted using various databases. Inclusion criteria were level 1 or 2 original studies, studies with patients reporting knee cartilage injuries and chondral defects, mean follow-up ≥2 years, and studies focusing on osteochondral transplant techniques. Exclusion criteria were studies with nonknee chondral defects, studies reporting clinical outcomes of osteochondral autograft or allograft combined with other procedures, animal studies, cadaveric studies, non-English language studies, case reports, and reviews or editorials. Primary outcomes included patient-reported outcomes and failure rates associated with both techniques, and factors such as lesion size, age, sex, and the number of plugs transplanted were assessed. Metaregression using a mixed-effects model was utilized for meta-analyses.

RESULTS

The search resulted in 20 included studies with 364 cases of osteochondral autograft and 272 cases of osteochondral allograft. Mean postoperative survival was 88.2% in the osteochondral autograft cohort as compared with 87.2% in the osteochondral allograft cohort at 5.4 and 5.2 years, respectively (P = .6605). Patient-reported outcomes improved by an average of 65.1% and 81.1% after osteochondral autograft and allograft, respectively (P = .0001). However, meta-analysis revealed no significant difference in patient-reported outcome percentage change between osteochondral autograft and allograft (P = .97) and a coefficient of 0.033 (95% CI, -1.91 to 1.98). Meta-analysis of the relative risk of graft failure after osteochondral autograft versus allograft showed no significant differences (P = .66) and a coefficient of 0.114 (95% CI, -0.46 to 0.69). Furthermore, the regression did not find other predictors (mean age, percentage of female patients, lesion size, number of plugs/grafts used, and treatment location) that may have significantly affected patient-reported outcome percentage change or postoperative failure between osteochondral autograft versus allograft.

CONCLUSION

Osteochondral autograft and allograft result in favorable patient-reported outcomes and graft survival rates at medium-term follow-up. While predictors for outcomes such as mean age, percentage of female patients, lesion size, number of plugs/grafts used, and treatment location did not affect the comparison of the 2 cohorts, proper patient selection for either procedure remains paramount to the success and potentially long-term viability of the graft.

Advances in Regenerative Sports Medicine Research

Regenerative sports medicine aims to address sports and aging-related conditions in the locomotor system using techniques that induce tissue regeneration. It also involves the treatment of meniscus and ligament injuries in the knee, Achilles’ tendon ruptures, rotator cuff tears, and cartilage and bone defects in various joints, as well as the regeneration of tendon–bone and cartilage–bone interfaces. There has been considerable progress in this field in recent years, resulting in promising steps toward the development of improved treatments as well as the identification of conundrums that require further targeted research. In this review the regeneration techniques currently considered optimal for each area of regenerative sports medicine have been reviewed and the time required for feasible clinical translation has been assessed. This review also provides insights into the direction of future efforts to minimize the gap between basic research and clinical applications.

[Surgical treatment of focal cartilage defects in the knee : Indications, techniques, modifications and results]

The treatment strategies for focal cartilage damage in the knee are multifarious. For established procedures, such as microfracturing (MFX), autologous matrix-induced chondrogenesis (AMIC), osteochondral transplantation (OCT) and autologous chondrocyte transplantation (ACT), well-founded, partly comparative long-term studies and overlapping size-dependent differential indications are available. Innovative cell sources, the utilization of biological scaffolds as well as biologic agents and various combinations, have recently become the focus of scientific attention; however, high regulatory demands are restricting their use in Germany. The success of every procedure is dependent on the appropriate indications, the treatment of comorbidities, such as axis deviations or ligamentous instability, the surgeon's experience and an adequate follow-up treatment.

Treatment of Juvenile Knee Osteochondritis Dissecans with a Cell-Free Biomimetic Osteochondral Scaffold: Clinical and MRI Results at Mid-Term Follow-up

OBJECTIVE

Osteochondral surgical procedures have been described for the treatment of unfixable osteochondritis dissecans (OCD), but only few of them have been studied for juvenile OCD (JOCD) lesions. A cell-free biomimetic osteochondral scaffold showed positive results in adult patients. The aim of this study was to evaluate the results of this scaffold for the treatment of knee JOCD at mid-term follow-up.

DESIGN

Twenty patients (14 males, 6 females) were included in this study. Mean age was 16.2 ± 1.4 years, average defect size was 3.2 ± 1.8 cm², and mean symptoms duration was 20.2 ± 17.9 months. After the implantation of the osteochondral collagen-hydroxyapatite scaffold (Maioregen, Fin-Ceramica, Faenza, Italy), patients were evaluated preoperatively and prospectively at 1, 2, and at final mean follow-up of 6 years (range 5-7 years) with International Knee Documentation Committee (IKDC) subjective and objective, Tegner, and EuroQol visual analogue scale (VAS) scores. MRI evaluation was performed with the MOCART 2.0 score.

RESULTS

All scores showed a significant improvement. IKDC subjective score went from 50.3 ± 17.4 preoperative score to 75.3 ± 14.6 at 1 year (P = 0.002), 80.8 ± 14.6 at 2 years and 85.0 ± 9.3 at 6 years. The Tegner score improved from the preoperative evaluation of 2.6 ± 1.4 to 5.5 ± 2.0 at 6 years (P < 0.0005), although without reaching the level registered before the onset of symptoms. A longer symptoms duration influenced negatively IKDC subjective and Tegner scores up to 2 years (P = 0.003 and P = 0.002, respectively) but did not affect the final outcome. Lesion size did not affect the final result. The MOCART 2.0 score showed a significant improvement between 1-year and final follow-up, but with persisting subchondral alterations.

CONCLUSIONS

This study demonstrated a clinical improvement stable over time with a high survival rate, although with persisting abnormal MRI findings, especially at subchondral bone level. This procedure can be considered a suitable option for the treatment of young patients affected by knee OCD. Level of evidence. Case series, level IV.

[Surgical treatment of focal cartilage defects in the knee : Indications, techniques, modifications and results]

The treatment strategies for focal cartilage damage in the knee are multifarious. For established procedures, such as microfracturing (MFX), autologous matrix-induced chondrogenesis (AMIC), osteochondral transplantation (OCT) and autologous chondrocyte transplantation (ACT), well-founded, partly comparative long-term studies and overlapping size-dependent differential indications are available. Innovative cell sources, the utilization of biological scaffolds as well as biologic agents and various combinations, have recently become the focus of scientific attention; however, high regulatory demands are restricting their use in Germany. The success of every procedure is dependent on the appropriate indications, the treatment of comorbidities, such as axis deviations or ligamentous instability, the surgeon's experience and an adequate follow-up treatment.

Development and Application of 3D Bioprinted Scaffolds Supporting Induced Pluripotent Stem Cells

Three-dimensional (3D) bioprinting is a revolutionary technology that replicates 3D functional living tissue scaffolds in vitro by controlling the layer-by-layer deposition of biomaterials and enables highly precise positioning of cells. With the development of this technology, more advanced research on the mechanisms of tissue morphogenesis, clinical drug screening, and organ regeneration may be pursued. Because of their self-renewal characteristics and multidirectional differentiation potential, induced pluripotent stem cells (iPSCs) have outstanding advantages in stem cell research and applications. In this review, we discuss the advantages of different bioinks containing human iPSCs that are fabricated by using 3D bioprinting. In particular, we focus on the ability of these bioinks to support iPSCs and promote their proliferation and differentiation. In addition, we summarize the applications of 3D bioprinting with iPSC-containing bioinks and put forward new views on the current research status.

Surgical management of focal chondral defects of the knee: a Bayesian network meta-analysis

Background

Focal chondral defects of the knee are common. Several surgical techniques have been proposed for the management of chondral defects: microfractures (MFX), osteochondral autograft transplantation (OAT), autologous matrix-induced chondrogenesis (AMIC) and autologous chondrocyte implantation (ACI)—first generation (pACI), second generation (cACI) and third generation (mACI). A Bayesian network meta-analysis was conducted to compare these surgical strategies for chondral defects in knee at midterm follow-up.

Methods

This Bayesian network meta-analysis was conducted according to the PRISMA extension statement for reporting of systematic reviews incorporating network meta-analyses of health care interventions. PubMed, Google Scholar, Embase and Scopus databases were accessed in July 2021. All the prospective comparative clinical trials investigating two or more surgical interventions for chondral defects of the knee were accessed. The network meta-analyses were performed through a Bayesian hierarchical random-effects model analysis. The log odds ratio (LOR) effect measures were used for dichotomic variables, while the standardized mean difference (SMD) for the continuous variables.

Results

Data from 2220 procedures (36 articles) were retrieved. The median follow-up was 36 (24 to 60) months. The ANOVA test found good baseline comparability between symptoms duration, age, sex and body mass index. AMIC resulted in higher Lysholm score (SMD 3.97) and Tegner score (SMD 2.10). AMIC demonstrated the lowest rate of failures (LOR −0.22) and the lowest rate of revisions (LOR 0.89). As expected, MFX reported the lower rate of hypertrophy (LOR −0.17) followed by AMIC (LOR 0.21). No statistically significant inconsistency was found in the comparisons.

Conclusion

AMIC procedure for focal chondral defects of the knee performed better overall at approximately 3 years’ follow-up.

Sporting participation following the operative management of chondral defects of the knee at mid-term follow up: a systematic review and meta-analysis

PURPOSE

The purpose of this study was to perform a systematic review of the reparticipation in sport at mid-term follow up in athletes who underwent biologic treatment of chondral defects in the knee and compare the rates amongst different biologic procedures.

METHODS

A search of PubMed/Medline and Embase was performed in May 2020 in keeping with Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines. The criteria for inclusion were observational, published research articles studying the outcomes and rates of participation in sport following biologic treatments of the knee with a minimum mean/median follow up of 5 years. Interventions included microfracture, osteochondral autograft transfer (OAT), autologous chondrocyte implantation (ACI), matrix-induced autologous chondrocyte implantation (MACI), osteochondral allograft, or platelet rich plasma (PRP) and peripheral blood stem cells (PBSC). A random effects model of head-to-head evidence was used to determine rates of sporting participation following each intervention.

RESULTS

There were twenty-nine studies which met the inclusion criteria with a total of 1276 patients (67% male, 33% female). The mean age was 32.8 years (13-69, SD 5.7) and the mean follow up was 89 months (SD 42.4). The number of studies reporting OAT was 8 (27.6%), ACI was 6 (20.7%), MACI was 7 (24.1%), microfracture was 5 (17.2%), osteochondral allograft was 4 (13.8%), and one study (3.4%) reported on PRP and PBSC. The overall return to any level of sport was 80%, with 58.6% returning to preinjury levels. PRP and PBSC (100%) and OAT (84.4%) had the highest rates of sporting participation, followed by allograft (83.9%) and ACI (80.7%). The lowest rates of participation were seen following MACI (74%) and microfracture (64.2%).

CONCLUSIONS

High rates of re-participation in sport are sustained for at least 5 years following biologic intervention for chondral injuries in the knee. Where possible, OAT should be considered as the treatment of choice when prolonged participation in sport is a priority for patients. However, MACI may achieve the highest probability of returning to the same pre-injury sporting level.

LEVEL OF EVIDENCE

IV.

Osteochondral Autologous Transplantation for Treating Patellar High-Grade Chondral Defects: A Systematic Review

Background:

Patellar cartilage defects account for 34.6% of defects found during routine arthroscopy. These defects pose a challenge in orthopaedic surgery because they have been associated with worse outcomes after surgical repair compared with other chondral lesions within the knee.

Purpose:

To systematically review the literature for evidence on results of osteochondral autologous transplantation (OAT) for the management of isolated patellar cartilage high-grade defects (International Cartilage Repair Society [ICRS] grade 3-4).

Study Design:

Systematic review; Level of evidence, 4.

Methods:

A systematic review of the literature was performed to find studies that addressed outcomes regarding OAT to treat patellar high-grade cartilage defects (ICRS grade 3-4). Studies addressing patient-reported outcomes, return to sports, or magnetic resonance imaging (MRI) at follow-up after isolated OAT procedures for patellar cartilage defects were included.

Results:

A total of 5 studies were included in this review. We were not able to perform a meta-analysis as no studies had available data. A total of 102 patients who received an isolated OAT for a patellar chondral defect were included in these 5 studies. All patients showed significant improvement at final follow-up based on the following patient-reported outcome scores: Lysholm, International Knee Documentation Committee, Kujala, Tegner, and 36-Item Short Form Health Survey. We found that 4 studies used MRI during the first postoperative year to assess osteochondral plug integration and positioning. The results demonstrated that most plugs were integrated and correctly positioned when evaluated at follow-up, conducted on average after 12 months. Whether patients were able to return to sports was queried in 2 of the included studies, revealing that patients could return to their previous level in most cases (Tegner score, 5-9 at 2 years after surgery).

Conclusion:

Results indicate that OAT is a safe and reliable technique to treat patellar high-grade osteochondral defects, allowing for significant improvement in patient-reported outcomes and return to sports.

Recombinant human FGF18 preserves depth-dependent mechanical inhomogeneity in articular cartilage

Articular cartilage is a specialised tissue that has a relatively homogenous endogenous cell population but a diverse extracellular matrix (ECM), with depth-dependent mechanical properties. Repair of this tissue remains an elusive clinical goal, with biological interventions preferred to arthroplasty in younger patients. Osteochondral transplantation (OCT) has emerged for the treatment of cartilage defects and osteoarthritis. Fresh allografts stored at 4 °C have been utilised, though matrix and cell viability loss remains an issue. To address this, several studies have developed media formulations to maintain cartilage explants in vitro. One promising factor for these applications is sprifermin, a human-recombinant fibroblast growth factor-18, which stimulates chondrocyte proliferation and matrix synthesis and is in clinical trials for the treatment of osteoarthritis. The study hypothesis was that addition of sprifermin during storage would maintain the unique depth-dependent mechanical profile of articular cartilage explants, a feature not often evaluated. Explants were maintained for up to 6 weeks with or without a weekly 24 h exposure to sprifermin (100 ng/mL) and the compressive modulus was assessed. Results showed that sprifermin-treated samples maintained their depth-dependent mechanical profile through 3 weeks, whereas untreated samples lost their mechanical integrity over 1 week of culture. Sprifermin also affected ECM balance by maintaining the levels of extracellular collagen and suppressing matrix metalloproteinase production. These findings support the use of sprifermin as a medium additive for OCT allografts during in vitro storage and present a potential mechanism where sprifermin may impact a functional characteristic of articular cartilage in repair strategies.

[Mid-term results in the treatment of osteochondritis dissecans of the femoral condyles using osteochondral grafting (mosaic arthroplasty)]

Several surgical procedures, including mosaic arthroplasty, can be used to treat patients with cartilage loss in the femoral condyles. This study aims to assess mid-term clinical and radiological results as well as the main prognostics elements. We conducted a retrospective epidemiological study over a period of 15 years. During the study period we collected data from 35 workable medical records of patients with osteochondritis dissecans of the femoral condyles treated by mosaic arthroplasty, with an average follow-up of 24 months. The level of complaints as well as preoperative knee function were evaluated and compared with the healthy knee according to the International Cartilage Repair Society (ICRS) score, the International Knee Documentation Committee (IKDC) score and visual analogue scale (VAS). It was less than 60% in 27 patients. During the follow-up period, the results were analyzed according to Hughston's functional and radiological criteria. After an average follow-up of 24 months, algoneurodystrophy was reported in 5 cases with a single case of haemarthrosis. A net ICRS score improvement was observed with a mean increasing from 54% to 74% on the follow-up visit. Most of patients were satisfied or very satisfied (82.9%). The elements of good prognosis recognized in our study included: a mean time between symptom onset and surgery of less of 18 months, having deep lesions with a diameter less than 02 cm and having lesions in the internal condyle. The treatment of cartilage loss is necessarily based on the correction of its direct and indirect causes namely the morphotype, the laxity and meniscus capital. No consensus in the decision-making was reached and no one could confirm the superiority of a technique in relation to the other but we can say that cartilage defect which sizes from 2 to 4 cm² may be the best indication for mosaic arthroplasty.

Osteochondritis Dissecans: Etiology, Pathology, and Imaging with a Special Focus on the Knee Joint

This article is a review of the current understanding of the etiology, pathogenesis, and how to diagnose and treat knee osteochondritis dissecans (OCD) followed by an analysis of and outcomes of the treatments available. OCD is seen in children and adolescents with open growth plates (juvenile OCD) and adults with closed growth plates (adult OCD). The etiology of OCD lesions remains unclear and is characterized by an aseptic necrosis in the subchondral bone area. Mechanical factors seem to play an important role. Clinical symptoms are unspecific. Thus, imaging techniques are most important. Regarding treatment, a tremendous number of publications exist. Spontaneous healing is expected unless there is an unstable fragment, and treatment involves rest and different degrees of immobilization until healing. Patients with open physes and low-grade lesions have good results with conservative therapy. When surgery is necessary, the procedure depends on the stage and on the state of the cartilage. With intact cartilage, retrograde procedures are favorable. When the cartilage is damaged, several techniques can be used. While techniques such as drilling and microfracturing produce reparative cartilage, other techniques reconstruct the defect with additional osteochondral grafts or cell-based procedures such as chondrocyte transplantation. There is a tendency toward better results when using procedures that reconstruct the bone and the cartilage and there is also a trend toward better long-term results when comorbidities are treated. Severe grades of osteoarthrosis are rare.

Treatment of osteochondral defects with a combination of bone grafting and AMIC technique

INTRODUCTION

Osteochondral defects of the knee may cause functional impairment of young and sportively active patients. Different surgical treatment options have been proposed using either one or two step procedures. The aim of the current study was to evaluate mid-term outcomes of combined bone grafting with autologous matrix-associated chondrogenesis (AMIC) for the treatment of large osteochondral defects.

MATERIALS AND METHODS

15 Patients with osteochondrosis dissecans of the medial femoral condyle grade III or IV according to ICRS classification were treated with a single step surgical procedure combining bone grafting and the AMIC procedure. Mean defect size was 4.98 cm² (± 3.02) and patients were examined at 6, 12 weeks, 6 and 12 month and at mean final follow-up of 49 months (36-61). Patients were evaluated using VAS, IKDC, KOOS, Lysholm, Tegner activity scores and psychological and physical health assessed using the SF 12. MRI evaluation was performed at final follow-up using the MOCART score.

RESULTS

Pain had significantly decreased at final follow-up (7.2 ± 1.4 vs. 2.4 ± 2.6) compared to preoperative baseline. All functional scores had improved significantly throughout the follow-up period (IKDC from 36.6 ± 20.6 vs. 72.2 ± 18.7; KOOS 50.0 ± 18.9 vs. 81.7 ± 13.9; LYSHOLM 39.3 ± 19.5 vs. 79.8 ± 15.1). SF12 evaluation showed a significant increase in physical component summary (PCS) (31.2 ± 11.1 preoperative vs. 46.3 ± 9.9 at final follow-up), while mental component summary (MCS) remained stable (51.8 ± 8.9 vs. 57.3 ± 3.3). MOCART score revealed a mean overall score of 77 ± 15 at final follow-up. Integration to the adjacent cartilage was complete in 79%, incomplete in 21%. Defect filling was complete in 64%, incomplete in 36%.

CONCLUSION

Significant improvement of knee function and restoration of homogenous cartilage morphology could be achieved with simultaneous AMIC procedure and bone grafting in 2/3 of all patients with large osteochondral lesions at 4 years postoperatively.

Large Osteochondral Allografts of the Knee: Surgical Technique and Indications

Large osteochondral allograft (OCA) transplant has become a valid alternative to restore articular surface in challenging articular lesions in young and active patients, either in primary or in revision procedures. Several studies support the effectiveness and safety of OCA, but costs and graft availability limit their use. The indications are the treatment of symptomatic full-thickness cartilage lesions greater than 3 cm ² , deep lesions with subchondral damage, or revision procedures when a previous treatment has failed. The goal of the transplant is to restore the articular surface with a biological implant, allow return to daily/sports activities, relieve symptoms, and delay knee arthroplasty. Grafts can be fresh, fresh-frozen, or cryopreserved; these different storage procedures significantly affect cell viability, immunogenicity, and duration of the storage. Dowel and shell technique are the two most commonly used procedures for OCA transplantation. While most cartilage lesions can be treated with the dowel technique, large and/or geometrically irregular lesions should be treated with the shell technique. OCA transplantation for the knee has demonstrated reliable mid- to long-term results in terms of graft survival and patient satisfaction. Best results are reported: in unipolar lesions, in patients younger than 30 years, in traumatic lesions and when the treatment is performed within 12 months from the onset of symptoms.

Functional outcomes after patellar autologous osteochondral transplantation

PURPOSE

The aim of the present study was to assess clinical evaluation of patients who underwent autologous osteochondral transplantation of the patella.

METHODS

This prospective study assessed outcomes of 20 patients who underwent patellar autologous osteochondral transplantation at four time-points: preoperatively, 3 days, 6 months, and 2 years after surgery. The following outcomes were assessed at each time-point: pain (VAS), gait, swelling, trophic status, muscle strength, patellar mobility, and range of motion. The Tegner scale was also applied for each time-point.

RESULTS

All parameters improved, except for patellar mobility, which did not show any change. Pain score decreased from 7.1 (SD 2.3) to 2.4 (SD 2.6) at the 2-year assessment; limping decreased from 70 % before surgery to 15 % 2 years later; swelling scores decreased from an average of 1.8 (SD 0.8) 3 days after surgery to 0.5 (SD 0.7) at the 2-year assessment; muscle strength increased from 3.9 (SD 0.8) to 4.7 (SD 0.7) points at final follow-up; and the range of motion increased from 84 (SD 16.2) to 132 (SD 10.7) degrees 2 years later. Tegner score before surgery ranged from 0 to 5, and after 2 years, it ranged from 5 to 9.

CONCLUSION

Autologous osteochondral transplantation for the treatment of patellar chondral lesion was associated with significant improvement in pain, gait, swelling, and range of motion 2 years after surgery, achieving scores similar to uninjured knees. Most of them were able to return to sports activity after 6 months (recreational level) and 2 years (competitive level).

LEVEL OF EVIDENCE

IV.

Osteochondral Allograft Transplantation for Treatment of Medial Femoral Condyle Defect

Chondral lesions of the knee can affect the young, active population, thereby causing severe morbidity and a large economic burden. Although numerous approaches have been described in the literature, restoration of hyaline cartilage has yet to be shown. Specifically, larger, full-thickness cartilage defects remain a challenge. This Technical Note details our technique for biologic unicompartmental osteochondral allograft transplantation for the treatment of large femoral condyle articular cartilage defects.

Combination of Collagen-Based Scaffold and Bioactive Factors Induces Adipose-Derived Mesenchymal Stem Cells Chondrogenic Differentiation In vitro

Recently, multipotent mesenchymal stem cells (MSCs) have attracted much attention in the field of regenerative medicine due to their ability to give rise to different cell types, including chondrocytes. Damaged articular cartilage repair is one of the most challenging issues for regenerative medicine, due to the intrinsic limited capability of cartilage to heal because of its avascular nature. While surgical approaches like chondral autografts and allografts provide symptoms and function improvement only for a short period, MSC based stimulation therapies, like microfracture surgery or autologous matrix-induced chondrogenesis demonstrate to be more effective. The use of adult chondrocytes, which are the main cellular constituent of cartilage, in medical practice, is indeed limited due to their instability in monolayer culture and difficulty to collect donor tissue (articular and nasal cartilage). The most recent cartilage engineering approaches combine cells, biomaterial scaffold and bioactive factors to promote functional tissue replacements. Many recent evidences demonstrate that scaffolds providing specific microenvironmental conditions can promote MSCs differentiation toward a functional phenotype. In the present work, the chondrogenic potential of a new Collagen I based 3D scaffold has been assessed in vitro, in combination with human adipose-derived MSCs which possess a higher chondrogenic potential compared to MSCs isolated from other tissues. Our data indicate that the scaffold was able to promote the early stages of chondrogenic commitment and that supplementation of specific soluble factors was able to induce the complete differentiation of MSCs in chondrocytes as demonstrated by the appearance of cartilage distinctive markers (Sox 9, Aggrecan, Matrilin-1, and Collagen II), as well as by the cartilage-specific Alcian Blue staining and by the acquisition of typical cellular morphology. Such evidences suggest that the investigated scaffold formulation could be suitable for the production of medical devices that can be beneficial in the field of articular cartilage engineering, thus improving the efficacy and durability of the current therapeutic options.

Repair of osteochondral defects with in vitro engineered cartilage based on autologous bone marrow stromal cells in a swine model

Functional reconstruction of large osteochondral defects is always a major challenge in articular surgery. Some studies have reported the feasibility of repairing articular osteochondral defects using bone marrow stromal cells (BMSCs) and biodegradable scaffolds. However, no significant breakthroughs have been achieved in clinical translation due to the instability of in vivo cartilage regeneration based on direct cell-scaffold construct implantation. To overcome the disadvantages of direct cell-scaffold construct implantation, the current study proposed an in vitro cartilage regeneration strategy, providing relatively mature cartilage-like tissue with superior mechanical properties. Our strategy involved in vitro cartilage engineering, repair of osteochondral defects, and evaluation of in vivo repair efficacy. The results demonstrated that BMSC engineered cartilage in vitro (BEC-vitro) presented a time-depended maturation process. The implantation of BEC-vitro alone could successfully realize tissue-specific repair of osteochondral defects with both cartilage and subchondral bone. Furthermore, the maturity level of BEC-vitro had significant influence on the repaired results. These results indicated that in vitro cartilage regeneration using BMSCs is a promising strategy for functional reconstruction of osteochondral defect, thus promoting the clinical translation of cartilage regeneration techniques incorporating BMSCs.

Fresh Osteochondral Allograft Transplantation for Treatment of Articular Cartilage Defects of the Knee

Articular cartilage damage of the knee can cause severe morbidity. Owing to its avascular nature, articular cartilage has limited potential for self-healing and increased propensity to progress to osteoarthritis. Treatment of large, full-thickness cartilage defects is still a challenge for orthopaedic surgeons but has recently achieved high success rates with the use of osteochondral allografts. This article details our technique of osteochondral allograft transplantation for the treatment of articular cartilage defects of the knee.

Osteochondral autografts

The healing potential for articular cartilage lesions is limited due to many physiological, local and mechanical factors. Spontaneous healing of partial- and full-thickness lesions is slow, and subsequent tissue response is usually not durable. In symptomatic, and high-demand, patients, a definitive treatment modality must be offered which allows for a sustained recovery with minimal debilitation. Injuries, which damage the subchondral bone, heal with the formation of fibrocartilage. This tissue fails long-term survival because of its inability to withstand the variable cyclic loads and compression forces that it is subjected to. While regeneration of the damaged cartilage by an entirely new articular surface is a goal beyond current available techniques, repair of the osteochondral defects with normal hyaline cartilage is possible by various options. Osteochondral defects that are larger then 2 cm are best treated by osteochondral autograft technique. The short-term outcomes of the present series show excellent results.

Osteochondral allograft transplant to the medial femoral condyle using a medial or lateral femoral condyle allograft: is there a difference in graft sources?

BACKGROUND

Osteochondral allograft (OCA) transplantation is an effective treatment for defects in the medial femoral condyle (MFC), but the procedure is limited by a shortage of grafts. Lateral femoral condyles (LFCs) differ in geometry from MFCs but may be a suitable graft source. The difference between articular surface locations of the knee can be evaluated with micro-computed tomography imaging and 3-dimensional image analysis.

HYPOTHESIS

LFC OCAs inserted into MFC lesions can provide a cartilage surface match comparable with those provided by MFC allografts.

STUDY DESIGN

Controlled laboratory study.

METHODS

Twenty MFCs and 10 LFCs were divided into 3 groups: 10 MFC recipients (MFCr), 10 MFC donors (MFCd), and 10 LFC donors (LFCd). A 20-mm defect was created in the weightbearing portion of the MFCr. Two grafts, 1 MFCd and 1 LFCd, were implanted sequentially into each MFCr. Micro-computed tomography (μCT) images of the MFCr were acquired and analyzed to compare the topography of the original recipient site with the MFCd- and LFCd-repaired sites. Three-dimensional transformations were defined to register the defect site in the 3 scans of each MFCr. Vertical deviations from each voxel of the graft cartilage surface, relative to the intact recipient cartilage surface, were calculated and assessed as root mean square deviation and percentage graft area that was proud, sunk, and within the "acceptable" distance (±1.00 mm). The effect of repair (with MFC vs with LFC) on each of the surface match parameters is presented as mean ± SD and was assessed by t test: height deviation over area (root mean square, mm), graft area acceptable (%), area unacceptably proud (%), area unacceptably sunk (%), step-off height over circumference (root mean square, mm), graft circumference acceptable (%), circumference unacceptably proud (%), and circumference unacceptably sunk (%). Percentage data were arcsin transformed before statistical testing. An alpha level of 0.05 was used to conclude if variations were statistically significant.

RESULTS

MFCr defects were filled with both orthotopic MFCd and nonorthotopic LFCd. Registered μCT images of the MFCr illustrate the cartilage surface contour in the sagittal and coronal planes, in the original intact condyle, as well as after OCA repairs. Specimen-specific surface color maps for the MFCr after implant of the MFCd and after implant of LFCd were generally similar, with some deviation near the edges. On average, the MFCr site exhibited a typical contour, and the MFCd and LFCd were slightly elevated. Both types of OCA-MFCd and LFCd-matched well, showing overall height deviations of 0.63 mm for area and 0.47 mm for step-off, with no significant difference between MFCd and LFCd (P = .92 and .57, respectively) and acceptable deviation based on area (87.6% overall) and step-off (96.7% overall), with no significant difference between MFCd and LFCd (P = .87 and .22, respectively). A small portion of the implant was proud (12.1% of area and 2.6% of circumference step-off height), with no significant difference between MFCd and LFCd (P = .26 and .27, respectively). A very small portion of the implant area and edge was sunk (0.3% of area and 0.6% of circumference), with no significant difference between MFCd and LFCd (P = .29 and .86, respectively).

CONCLUSION/CLINICAL RELEVANCE

The achievement of excellent OCA surface match with an MFCd or LFCd graft into the common MFCr site suggests that nonorthotopic LFC OCAs are acceptable graft options for MFC defects.

Arthroscopic debridement of unicompartmental arthritis: fact or fiction?

Patients with recurrent or mechanical symptoms of unicompartmental knee arthritis that have failed conservative management are candidates for surgical intervention. Surgical options include debridement, lavage, chondroplasty, bone marrow-stimulating techniques, chondrocyte transfer, and chondrocyte implantation. These techniques have been well studied but it is still unclear which technique is superior. Various factors need to be accounted for when choosing the proper technique; among the factors discussed are the patient's age and the size of the articular cartilage defect.

Fate of large donor site defects in osteochondral transfer procedures in the knee joint with and without TruFit plugs

INTRODUCTION

Because of the potential donor site morbidity, cartilage lesions of more than 3 cm(2) in size are considered to be critical regarding autologous osteochondral transplantation (OCT). In this study, the potential donor site morbidity for large defects should be reduced by means of OBI TruFit Plugs.

MATERIALS AND METHODS

An autologous OCT was carried out on 37 patients and the cylinders were received from the dorsal medial femoral condyle. The donor site defects of 21 patients (average defect size 5.5 cm(2)) were filled with artificial TruFit cylinders (study group); the donor site defects (average defect size 4.6 cm(2)) were left untreated for 16 patients.

RESULTS

In the study group, the Tegner, Western Ontario and McMaster Universities (WOMAC), knee society score, and visual analogue scale pain scores improved from preoperatively 3.2 (±0.8), 60.9 (±41.6), 133.6 (±27.1), and 4.8 (±2.3) points, respectively, to 3.9 (±0.6), 35.5 (±27.1), 177.8 (±16.6), and 3.3 (±2.9) points, respectively, at the time of the second follow-up; the control group's preoperative score values came to 2.8 (±0.9), 73.3 (±50.2), 123.8 (±41.5), and 5.3 (±2.7) points, respectively, and changed to 3.6 (±0.8), 41.4 (±28.8), 179.3 (±17.5), and 3.1 (±2.0) points, respectively, at the time of the second follow-up. The smaller the initial chondral defect was in the study group, the better the WOMAC score values became (p < 0.05). The modified Henderson score at the study group's donor sites improved from 19.2 (±3.3) to 13.7 (±2.1) points (p < 0.001); the control group's score values for the donor sites were 18.3 (±3.4) and 15.4 (±4.4) points (p = 0.0015).

CONCLUSIONS

OCT is an effective therapy even for large chondral defects >3 cm(2). By filling the defects with TruFit implants, no clinical improvements could be found since the donor site morbidity was already low anyway. However, the regeneration of defects filled with TruFit implants took more than 2 years.

Evidence-based status of osteochondral cylinder transfer techniques: a systematic review of level I and II studies

PURPOSE

Our purpose was to examine the Level I and II evidence for the use of osteochondral cylinder transfer technique (OCT) for cartilage repair.

METHODS

A literature search was carried out for Level I and II evidence studies on cartilage repair using the PubMed database. All the studies that involved OCT were identified. Only Level I and II studies that compared OCT to other modalities of treatment such as microfracture (MF) and autologous chondrocyte implantation (ACI) were selected.

RESULTS

A total of 8 studies matched the selection criteria with 2 Level I and 6 Level II studies. Four studies compared OCT with MF, 3 compared OCT with ACI, and one compared all 3 techniques. Of 3 studies, 4 came from a single center. Mean age of patients ranged from 24 to 33 years, and mean follow-up ranged from 9 to 124 months. The studies from the single center showed superior results from OCT over MF, especially in younger patients, with one study having long-term follow-up of 10 years. They also showed an earlier return to sports. The size of the lesions were small (average < 3 cm(2)). The 4 other independent studies did not show any difference between OCT and ACI, with one study showing inferior outcome in the OCT group. Magnetic resonance imaging (MRI) showed good osseous integration of the osteochondral plugs to the subchondral bone. Histologic examination showed that there was hyaline cartilage in the transplanted osteochondral plugs but no hyaline cartilage between the plugs.

CONCLUSIONS

From the studies of a single center, OCT had an advantage over MF in younger patients with small chondral lesions. Comparison of outcomes between OCT and ACI showed no significant difference in 2 studies and contrasting results in another 2 studies. There was insufficient evidence for long-term results for OCT.

LEVEL OF EVIDENCE

Level II, systematic review of Level I and II studies.

Microfracture technique versus osteochondral autologous transplantation mosaicplasty in patients with articular chondral lesions of the knee: a prospective randomized trial with long-term follow-up

PURPOSE

To compare long-term functional and radiological outcome following microfracture technique (MF) versus osteochondral autologous transplantation (OAT) mosaicplasty for treating focal chondral lesions of the knee.

METHODS

Twenty-five patients (mean age 32.3 years, SD 7.7) with a full-thickness (International Cartilage Repair Society grade 3 or 4) chondral lesion of the articulating surface of the femur were randomized to either MF (n = 11) or OAT mosaicplasty (n = 14). At a median follow-up of 9.8 years (range 4.9-11.4), the patients were evaluated using Lysholm score (n = 25), Knee Injury and Osteoarthritis Outcome Score (KOOS, n = 25), isokinetic quadriceps measurement and hamstring strength measurement (n = 22) and standing radiographs (n = 23).

RESULTS

There were no significant differences in Lysholm score, KOOS, isokinetic muscle strength or radiographic osteoarthritis between MF-treated patients and OAT mosaicplasty-treated patients at follow-up. Mean Lysholm score at follow-up was 69.7 [95% confidence interval (CI), 55.1-84.4] for the MF group and 62.6 (95% CI, 52.6-72.6) for the OAT mosaicplasty group.

CONCLUSION

At long-term follow-up, there were no significant differences between patients treated with MF and patients treated with OAT mosaicplasty in patient-reported outcomes, muscle strength or radiological outcome.

LEVEL OF EVIDENCE

Therapeutic study, Level II.

An analysis of surface profile for cylindrical osteochondral grafts of the knee quantitative evaluation using a three-dimensional laser scanner

PURPOSE

To investigate the congruency of the articular cartilage surface of the knee between the recipient and donor site during autogenous osteochondral grafting using a three-dimensional (3D) laser scanning.

METHODS

Six cadaveric knees were included in this study. The 3D profiles of the articular surface were obtained by a 3D laser scanner (FastSCAN(®), Polhemus). We divided each of the donor and recipient sites into 6 areas in each. The 2 central areas of the donor site were excluded from evaluation because of the trochlear groove. In the donor site, the peripheral and the middle one-third of the femoral articular surface in the medial and lateral patellofemoral joint were extracted. In the recipient site, the peripheral and the middle one-third of the articular surface in the medial and lateral femoral condyle were assessed. In each recipient area, vertical intervals (VIs) of grafts of 6, 8, and 10 mm diameter, showing the distance between highest and lowest point of articular surface were calculated from the data obtained and to the donor sites for matching.

RESULTS

ϕ6- and ϕ8-mm grafts The VI of the middle area of the donor site did not differ significantly from that of either the peripheral or the middle area of the recipient site. The VI of the peripheral area of the donor site was significantly higher than that of the peripheral area of the recipient site (p < 0.01). ϕ10-mm grafts The VI of the middle area of the donor site was significantly lower than that of the peripheral area of the recipient site. The VI of the peripheral area of the donor site was significantly higher than that of the middle area of the recipient site (p < 0.01).

CONCLUSIONS

An osteochondral graft harvested from the peripheral area of the patellofemoral joint might protrude into the middle area in the recipient site, whereas a ϕ10-mm osteochondral graft harvested from the middle area might be depressed from the peripheral area into the recipient site.

Controlled release strategies for bone, cartilage, and osteochondral engineering--Part I: recapitulation of native tissue healing and variables for the design of delivery systems

The potential of growth factors to stimulate tissue healing through the enhancement of cell proliferation, migration, and differentiation is undeniable. However, critical parameters on the design of adequate carriers, such as uncontrolled spatiotemporal presence of bioactive factors, inadequate release profiles, and supraphysiological dosages of growth factors, have impaired the translation of these systems onto clinical practice. This review describes the healing cascades for bone, cartilage, and osteochondral interface, highlighting the role of specific growth factors for triggering the reactions leading to tissue regeneration. Critical criteria on the design of carriers for controlled release of bioactive factors are also reported, focusing on the need to provide a spatiotemporal control over the delivery and presentation of these molecules.

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.

Factors affecting the outcome of osteochondral autografting (mosaicplasty) in articular cartilage defects of the knee joint: retrospective analysis of 152 cases

OBJECTIVE

The purpose of this retrospective study was to evaluate the results and prognostic factors affecting the outcome of osteochondral autografting (mosaicplasty) in articular cartilage defects of the knee joint.

MATERIALS AND METHODS

One hundred fifty-two patients who underwent mosaicplasty for femoral condylar cartilage defects (modified Outerbridge classification: Grade III and IV) of the knee joint between 1998 and 2007 in our institution were included. There were 126 male and 26 female patients with a mean age of 24.8 ± 4.6 years. The average size of the lesion was 2.7 ± 0.7 cm(2). Of these patients, 33 had concomitant meniscal and/or cruciate ligament injuries which were treated simultaneously. All patients were followed up with a mean of 18.2 ± 4.2 months (range 12-24 months) using Lysholm knee score. We analyzed the relationship between the outcome variable (Lysholm knee score at the final follow-up) and the predictor variables (age, gender, lesion size, lesion grade, localization, accompanying intra-articular injuries and duration of follow-up).

RESULTS

The mean preoperative Lysholm knee score was 55.2 ± 3.6 points and increased to 88.2 ± 2.5 points at the final follow-up. There was a significant increase in Lysholm score during follow-up period (p = 0.0001). The results were excellent in 2 cases (1.3 %), good in 144 cases (94.7 %) and fair in 6 cases (3.9 %). No patients had infection, systemic complication and revision surgery. Backward regression analysis showed that age, lesion size, localization and associated intraarticular injuries are the only predictors of the final Lysholm knee score in best fit model (R (2) = 0.442, p = 0.0001). The linear regression equation was (Lysholm score at final follow-up) = 93.4 - [0.2 (age of patient) + 0.8 (lesion size) + 0.9 (localization) + 2.8 (presence of associated intraarticular injuries)].

CONCLUSIONS

Mosaicplasty is an effective technique for the treatment of articular cartilage defects of the knee joint which restores the joint function in a short period of follow-up. Furthermore, age, lesion size, localization, and concomitant surgical interventions are major factors affecting the final outcome. The final knee score deteriorates as the age of the patient and size of the lesion increases. Furthermore, concomitant surgical interventions and lesions located on the medial femoral condyle have a negative effect on the final knee score.

Image-Guided Techniques Improve the Short-Term Outcome of Autologous Osteochondral Cartilage Repair Surgeries: An Animal Trial

OBJECTIVE

Autologous osteochondral cartilage repair is a valuable reconstruction option for cartilage defects, but the accuracy to harvest and deliver osteochondral grafts remains problematic. We investigated whether image-guided methods (optically guided and template guided) can improve the outcome of these procedures.

DESIGN

Fifteen sheep were operated to create traumatic chondral injuries in each knee. After 4 months, the chondral defect in one knee was repaired using (a) conventional approach, (b) optically guided method, or (c) template-guided method. For both image-guided groups, harvest and delivery sites were preoperatively planned using custom-made software. During optically guided surgery, instrument position and orientation were tracked and superimposed onto the surgical plan. For the template-guided group, plastic templates were manufactured to allow an exact fit between template and the joint anatomy. Cylindrical holes within the template guided surgical tools according to the plan. Three months postsurgery, both knees were harvested and computed tomography scans were used to compare the reconstructed versus the native pre-injury joint surfaces. For each repaired defect, macroscopic (International Cartilage Repair Society [ICRS]) and histological repair (ICRS II) scores were assessed.

RESULTS

Three months after repair surgery, both image-guided surgical approaches resulted in significantly better histology scores compared with the conventional approach (improvement by 55%, P < 0.02). Interestingly, there were no significant differences found in cartilage surface reconstruction and macroscopic scores between the image-guided and the conventional surgeries.

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.

Bioabsorbable pins for treatment of osteochondral fractures of the knee after acute patella dislocation in children and young adolescents

A retrospective study was performed on the use of bioabsorbable pins in the fixation of osteochondral fractures (OCFs) after traumatic patellar dislocation in children. Eighteen children (13 females, 5 males) aged 11 to 15 years (mean age 13.1 years) with osteochondral fracture (OCF) of the knee joint were treated at the authors' institution. Followup ranged from 22 months to 5 years. Diagnosis was verified by X-ray and magnetic resonance imaging (MRI) of the knee and patella. In seven patients the osteochondral fragment was detached from the patella and in 11 it was detached from the lateral femoral condyle. All patients were subjected to open reduction and fixation of the lesion with bioabsorbable pins. Postoperatively, the knee was immobilized in a cast and all patients were mobilized applying a standardized protocol. Bone consolidation was successful in 17 of the 18 patients. Bioabsorbable pins reliably fix OCF in children and adolescents, demonstrating a high incidence of consolidation of the detached osteochondral fragment in short- and middle-term followup without requiring further operative procedures.

Surgical treatment of articular cartilage defects in the knee: are we winning?

Articular cartilage (AC) injury is a common disorder. Numerous techniques have been employed to repair or regenerate the cartilage defects with varying degrees of success. Three commonly performed techniques include bone marrow stimulation, cartilage repair, and cartilage regeneration. This paper focuses on current level of evidence paying particular attention to cartilage regeneration techniques.

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.

Mosaic osteochondral transplantations in the knee joint, midterm results of the SFA multicenter study

INTRODUCTION

There are several possible options to treat focal articular cartilage defects of the knee. The aim of this study was to evaluate the results and prognostic factors cartilage defects of the knee treated by autologous osteochondral mosaicplasty after more than five years of follow-up.

PATIENTS AND METHODS

One hundred forty-two cases were included in this retrospective multicenter study. Etiologies included osteochondral fractures (n=79), and osteochondritis dissecans (n=61). Mean age of patients was 31. There was a majority of men (76%). Mean BMI was 25 (range: 21-41). Fifty-three percent of the knees had a history of surgery. Mean delay between the accident and surgery was 2.5 years. Mean area of the defect was 2.29 cm(2) (range: 0.3-12.25 cm(2)). The depth of the defect was 3 or 4 on the ICRS score in 97% of cases. An additional surgical procedure was associated with mosaicplasty in 14% of the cases. The follow-up evaluation was based on the Hughston score, the ICRS score, the IKDC subjective score, and the IKDC radiological score. Evaluation of control MRI was based on a modified MOCART score.

RESULTS

The mean follow-up was 96 ± 28 months. There were complications in 19 patients. Patients were able to begin athletic activities again after a mean 35 weeks. Most patients (81.8%) were satisfied or very satisfied. There was a significant improvement (p<0.001) in the ICRS, IKDC function and Hughston scores at follow-up. The factors for a good prognosis were: male gender, medial femoral condyle defects, osteochondritis dissecans, deep, small defects, and the shortest possible delay to surgery. Obesity, smoking, work-related accidents, the level of sports practiced, the percentage of coverage of the defect, the number of plugs, and associated lesions did not have a statistically significant effect on the functional results in the final follow-up.

DISCUSSION

Autologous osteochondral mosaicplasty seems to be a reliable technique in the short and intermediate term. It has the advantage of being less expensive than reconstructive techniques, is a one-step surgical procedure and results in immediate restoration of cartilage surface. Nevertheless, this is a difficult technique, which may result in complications and requires articular harvesting. This technique is limited by the size of the defect to be treated. The primary indication is deep, small defects on the medial femoral condyle.

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.

The effects of the synovium on chondrocyte growth: an experimental study

PURPOSE

The objective of this study was to evaluate the effects of synovium on the proliferation of the cartilage tissue and chondrocytes using a rabbit knee model as an in vivo synovial culture medium.

METHODS

Twelve New Zealand rabbits were used as the animal model in this investigation. Standard size chondral and osteochondral cartilage grafts were taken from, respectively, the left and right knees of all the animals. Two groups of 6 animals were formed: in Group I (synovium group), grafts were placed into the synovial tissue and in group II (patellar tendon group) behind the patellar tendon of the corresponding knees. After 4 months, samples were collected and evaluated macroscopically by measuring their dimensions (vertical = D1, horizontal = D2, and depth = D3) and volumes, and histologically by counting the chondrocyte number using camera lucida method.

RESULTS

Macroscopically, the increase in average D1, D2, and D3 measurements and volume in the osteochondral specimens were significantly higher compared to the chondral specimens in both groups (P < 0.05). However, no significant difference was observed between the two groups in terms of macroscopic values. Histologically, the mean chondrocyte counts in osteochondral and chondral specimens for Group I (synovium) were 20.2 and 18.1, and for Group II (patellar tendon) were 18.7 and 15.6, respectively. The mean number of chondrocytes was found to be significantly higher in osteochondral specimens than that of chondral specimens in either group (P < 0.05). Overall average chondrocyte count was significantly higher for Group I compared to Group II (P < 0.05).

CONCLUSION

Transplantation of the cartilage grafts into the synovial tissue in rabbit knees significantly enhanced the chondrocyte production compared with the group where the grafts were transplanted into intra-articular patellar tendon. The results of this study indicate that native synovial tissue may have the potential to be used as an in vivo culture medium for osteochondral tissue growth.

We do not have evidence based methods for the treatment of cartilage defects in the knee

PURPOSE

The aim of this study was to perform a systematic review of studies concerning current treatment of chondral defects of the knee.

METHODS

The relevance for evidence based data and for successful surgical treatment of cartilage defects was evaluated. From 56,098 evaluated studies, 133 studies could be further pursued. These supplied data concerning microfracturing, the osteochondral autograft transplantation system (OATS), the autologous chondrocyte implantation (ACI) and the matrix induced chondrocyte implantation (MACI). The modified Coleman Methodical Score (CMS) and the Level of Evidence (LOE) were applied to evaluate the quality.

RESULTS

In these studies, a total of 6,920 patients were reviewed with a median of 32 patients per study and a mean follow-up of 24 months. The mean CMS was 58 of 100 points. No study reached 100 points in the CMS. Three studies reached a level above 90. Ten studies were Level I, five studies reached Level II. Seven studies reached Level III, 111 studies Level IV. MRI scans to verify the clinical data were used by only 72 studies. The means in the modified CMS were for the different procedures as follows: ACI 58 points, MACI 57 points, microfracturing 68 points and OATS 50 points. 24 studies applied the Lysholm Score (LS) for clinical evaluation of cartilage surgery. All operative procedures yielded comparable improvements of the LS (n.s.) meaning that no operative procedure proved superior.

CONCLUSION

As the majority of studies evaluated by this review is insufficient for EBM purposes more coherent studies with LOE of I or II are needed. Co-relating the systems of CMS and LOE and validating the applied scores seems desirable.

Can osteochondral grafting be augmented with microfracture in an extended-size lesion of articular cartilage?

BACKGROUND

Both microfracture and osteochondral autografting procedures have been useful in treating osteochondral lesions.

HYPOTHESIS

Combining microfracture and osteochondral autografting procedures can extend the size of lesions that can be treated with either technique.

STUDY DESIGN

Descriptive laboratory study.

METHODS

Eight adult goats underwent osteochondral autograft transfer of a 4.5-mm femoral trochlea plug into an 8-mm full-thickness chondral defect. Microfracture was performed in the gap region surrounding the autograft. The animals were allowed normal activity until the end of the experiment at 6 months. At harvest, the knees were assessed grossly, and then evaluation was performed by histology, histomorphometry, biochemistry, and biomechanics.

RESULTS

The osteochondral plugs healed well, with integration of the bone and preservation of the chondral cap. The chondral gap between the host site articular cartilage and the transferred plug had decreased from 3 mm at implant to less than 0.1 mm. Histologic analysis demonstrated regions of variable cartilage repair, with integration of the cartilage layer at some sites but incomplete healing at others. Histomorphometry demonstrated filling of the chondral gap to 75% to 85% of the normal volume. Biochemical analysis revealed greater than 90% type II collagen at most sites, with some areas containing 80% type II collagen. Biomechanical indentation testing indicated that the repaired area had variable thickness and stiffness, with a trend of increased stiffness in the bulk graft and decreased softness at the proximal microfracture interface site.

CONCLUSION

The performance of a combined microfracture and osteochondral autograft transfer procedure to resurface a large chondral defect appears promising.

CLINICAL RELEVANCE

This combined technique shows promise for treatment of large chondral defects with a single operative procedure with autogenous tissue that is safe and potentially would have a shorter period of rehabilitation, similar to that of osteochondral transfers and microfracture, in a cost-effective setting.

Articular Cartilage Injury in Athletes

Articular cartilage lesions in the athletic population are observed with increasing frequency and, due to limited intrinsic healing capacity, can lead to progressive pain and functional limitation over time. If left untreated, isolated cartilage lesions can lead to progressive chondropenia or global cartilage loss over time. A chondropenia curve is described to help predict the outcome of cartilage injury based on different lesion and patient characteristics. Nutriceuticals and chondroprotective agents are being investigated as tools to slow the development of chondropenia. Several operative techniques have been described for articular cartilage repair or replacement and, more recently, cartilage regeneration. Rehabilitation guidelines are being developed to meet the needs of these new techniques. Next-generation techniques are currently evaluated to optimize articular cartilage repair biology and to provide a repair cartilage tissue that can withstand the high mechanical loads experienced by the athlete with consistent long-term durability.

Bone scintigraphy after osteochondral autograft transplantation in the knee: 13 patients followed for 4 years

BACKGROUND AND PURPOSE

Autologous osteochondral transplantation (OCT) is an established method of treating articular cartilage defects in the knee. However, the potential for donor site morbidity remains a concern. Both the restoration of the original cartilage defect and the evolution of the donor site defects can be evaluated by bone scintigraphy. Thus, we performed a prospective bone scintigraphic evaluation in patients who were treated with OCT.

PATIENTS AND METHODS

In 13 patients with a symptomatic articular cartilage defect, bone scintigraphies were obtained preoperatively, 1 year after osteochondral transplantation, and finally at an average follow-up of 4 (2.5-5.5) years. The evolution of scintigraphic activity was evaluated for both the recipient and the donor site. Parallel, clinical scoring was performed using the Lysholm knee scoring scale, the Cincinnati knee rating system, and the Tegner activity score.

RESULTS

The bone scintigraphic uptake was elevated at the involved femoral condyle preoperatively, and gradually decreased to normal levels in 7 of 11 cases. The originally normal uptake at the trochlea increased 1 year after transplantation. Then, a gradual decrease in uptake occurred again at this donor site to remain elevated at the final scintigraphy. A correlation was found between elevated scintigraphic activity and the presence of retropatellar crepitus. The mean Lysholm and Cincinnati scores had increased 1 year after transplantation. The mean Tegner score had increased 3 years after transplantation.

INTERPRETATION

Elevated bone scintigraphic activity from an osteochondral lesion in the knee can be restored with OCT. However, increased scintigraphic activity is introduced at the donor site, which becomes reduced with longer follow-up. The use of fairly large osteochondral plugs appears to correlate with retropatellar crepitus and increased scintigraphic activity, and is not therefore recommended.

Osteochondral transfer using a transmalleolar approach for arthroscopic management of talus posteromedial lesions

Characterizing osteochondral lesions of the talus has enabled the strategies of surgical management to be better specified. The main technical problem is one of access for arthroscopy instruments to posteromedial lesions. A range of techniques and approaches has been described in ankle arthroscopy in general, and a transmalleolar approach provides reliable and efficient access in these cases. It is frequently used for transchondral drilling, but also enables satisfactory implant positioning in autologous osteochondral mosaicplasty procedures. We report our technique and results on five cases with a minimum 1.2 years' follow-up.

Mesenchymal stem cells: innovative therapeutic tools for rheumatic diseases

Mesenchymal stem cells (MSCs), or multipotent mesenchymal stromal cells as they are also known, have been identified in bone marrow as well as in other tissues of the joint, including adipose, synovium, periosteum, perichondrium, and cartilage. These cells are characterized by their phenotype and their ability to differentiate into three lineages: chondrocytes, osteoblasts and adipocytes. Importantly, MSCs also potently modulate immune responses, exhibit healing capacities, improve angiogenesis and prevent fibrosis. These properties might be explained at least in part by the trophic effects of MSCs through the secretion of a number of cytokines and growth factors. However, the mechanisms involved in the differentiation potential of MSCs, and their immunomodulatory and paracrine properties, are currently being extensively studied. These unique properties of MSCs confer on them the potential to be used for therapeutic applications in rheumatic diseases, including rheumatoid arthritis, osteoarthritis, genetic bone and cartilage disorders as well as bone metastasis.

Osteochondral grafting: effect of graft alignment, material properties, and articular geometry

Osteochondral grafting for cartilage lesions is an attractive surgical procedure; however, the clinical results have not always been successful. Surgical recommendations differ with respect to donor site and graft placement technique. No clear biomechanical analysis of these surgical options has been reported. We hypothesized that differences in graft placement, graft biomechanical properties, and graft topography affect cartilage stresses and strains. A finite element model of articular cartilage and meniscus in a normal knee was constructed. The model was used to analyze the magnitude and the distribution of contact stresses, von Mises stresses, and compressive strains in the intact knee, after creation of an 8-mm diameter osteochondral defect, and after osteochondral grafting of the defect. The effects of graft placement, articular surface topography, and biomechanical properties were evaluated. The osteochondral defect generated minimal changes in peak contact stress (3.6 MPa) relative to the intact condition (3.4 MPa) but significantly increased peak von Mises stress (by 110%) and peak compressive strain (by 63%). A perfectly matched graft restored stresses and strains to near intact conditions. Leaving the graft proud by 0.5 mm generated the greatest increase in local stresses (peak contact stresses = 6.7 MPa). Reducing graft stiffness and curvature of articular surface had lesser effects on local stresses. Graft alignment, graft biomechanical properties, and graft topography all affected cartilage stresses and strains. Contact stresses, von Mises stresses, and compressive strains are biomechanical markers for potential tissue damage and cell death. Leaving the graft proud tends to jeopardize the graft by increasing the stresses and strains on the graft. From a biomechanical perspective, the ideal surgical procedure is a perfectly aligned graft with reasonably matched articular cartilage surface from a lower load-bearing region of the knee.