Sandwich Technique for Large Osteochondral Lesions of the Knee

OBJECTIVE

To evaluate whether a sandwich technique procedure for large osteochondral lesions (OCL) of the medial femur condyle reduces clinical symptoms and improves activity level as well as to assess repair tissue integration on MRI over 2 years.

DESIGN

Twenty-one patients (median age: 29 years, 18-44 years) who received matrix-associated autologous chondrocyte transplantation (MACT) combined with cancellous bone grafting at the medial femur condyle in a 1-step procedure were prospectively included. Patients were evaluated before surgery (baseline) as well as 3, 6, 12, and 24 months postoperatively, including clinical evaluation, Lysholm score, Tegner Activity Rating Scale, and MRI with Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) score and a modified Whole-Organ Magnetic Resonance Imaging Score (WORMS).

RESULTS

Seventeen patients were available for the 24-month (final) follow-up (4 dropouts). Lysholm significantly improved from 48 preoperatively stepwise to 95 at final follow-up (P < 0.05). Tegner improvement from 2.5 at baseline to 4.0 at final follow-up was not significant (P = 1.0). MOCART score improved significantly and stepwise from 65 at 3 months to 90 at 24 months (P < 0.05). Total WORMS improved from 14.5 at surgery to 7.0 after 24 months (P < 0.05). Body mass index and defect size at surgery correlated with total WORMS at final follow-up (P < 0.05) but did not correlate with clinical scores or defect filling.

CONCLUSION

MACT combined with cancellous bone grafting at the medial femoral condyle reduces symptoms continuously over 2 years. A 1-step procedure may reduce perioperative morbidity. However, despite improvements, patients' activity levels remain low, even 2 years after surgery.

Osteochondral Repair and Electromechanical Evaluation of Custom 3D Scaffold Microstructured by Direct Laser Writing Lithography

OBJECTIVE

The objective of this study was to assess a novel 3D microstructured scaffold seeded with allogeneic chondrocytes (cells) in a rabbit osteochondral defect model.

DESIGN

Direct laser writing lithography in pre-polymers was employed to fabricate custom silicon-zirconium containing hybrid organic-inorganic (HOI) polymer SZ2080 scaffolds of a predefined morphology. Hexagon-pored HOI scaffolds were seeded with chondrocytes (cells), and tissue-engineered cartilage biocompatibility, potency, efficacy, and shelf-life in vitro was assessed by morphological, ELISA (enzyme-linked immunosorbent assay) and PCR (polymerase chain reaction) analysis. Osteochondral defect was created in the weight-bearing area of medial femoral condyle for in vivo study. Polymerized fibrin was added to every defect of 5 experimental groups. Cartilage repair was analyzed after 6 months using macroscopical (Oswestry Arthroscopy Score [OAS]), histological, and electromechanical quantitative potential (QP) scores. Collagen scaffold (CS) was used as a positive comparator for in vitro and in vivo studies.

RESULTS

Type II collagen gene upregulation and protein secretion was maintained up to 8 days in seeded HOI. In vivo analysis revealed improvement in all scaffold treatment groups. For the first time, electromechanical properties of a cellular-based scaffold were analyzed in a preclinical study. Cell addition did not enhance OAS but improved histological and QP scores in HOI groups.

CONCLUSIONS

HOI material is biocompatible for up to 8 days in vitro and is supportive of cartilage formation at 6 months in vivo. Electromechanical measurement offers a reliable quality assessment of repaired cartilage.

Osteochondritis Dissecans of Smaller Joints: The Elbow

This review presents the current understanding of the etiology, pathogenesis, and how to diagnose and treat osteochondritis dissecans (OCD) at the elbow joint followed by an analysis of particular characteristics and outcomes of the treatment. OCD is seen in patients with open growth plates (juvenile OCD [JOCD] and in adults [AOCD] with closed growth plates [adult OCD). The etiology at smaller joints remains as unclear as for the knee. Mechanical factors (throwing activities [capitulum] seem to play an important role. Clinical symptoms are unspecific. Thus, imaging techniques are most important for the diagnosis. In low-grade and stable lesions, treatment involves rest and different degrees of immobilization until healing. When surgery is necessary, the procedure depends on the OCD stage and on the state of the cartilage. With intact cartilage, retrograde procedures are favorable while with damaged cartilage, several techniques are used. Techniques such as drilling and microfracturing produce a reparative cartilage while other techniques reconstruct the defect with osteochondral grafts or cell-based procedures such as chondrocyte implantation. There is a tendency toward better results when reconstructive procedures for both the bone and cartilage are used. In addition, comorbidities at the joint have to be treated. Severe grades of osteoarthritis are rare.

Validation of the Oswestry Risk of Knee Arthroplasty Index (ORKA-1) for Patients Undergoing Autologous Chondrocyte Implantation

OBJECTIVE

The purpose of this study was first to externally validate the Oswestry Risk of Knee Arthroplasty index (ORKA-1) by applying it to an autologous chondrocyte implantation (ACI) patient cohort in the United States with a broader definition of failure than only arthroplasty, and second, to determine predictive factors for the risk of ACI failure as defined by the senior author.

DESIGN

A total of 171 patients that underwent ACI were included to validate the ORKA-1 as all factors needed for calculation and outcomes were recorded. For Cox regression analysis, 154 patients were included as they completed preoperative Knee Injury and Osteoarthritis Outcome Score (KOOS), Tegner, Lysholm, International Knee Documentation Committee (IKDC), and 12-item Shor Form (SF-12) scores. Patient- and lesion-associated parameters were recorded for each patient.

RESULTS

At final follow-up (maximum of 10 years post-ACI), a total of 27 patients (15.8%) were considered a failure by senior author's definition. With ACI failure as endpoint, the mean survival was 7.96 years in risk group 1 and 5.4 years in risk group 5. Cox regression analysis identified preoperative KOOS Sport/Recreation as the only significant predictive factor for ACI failure (P = 0.007).

CONCLUSION

The ORKA-1 is a helpful tool for surgeons to estimate an individual patient's likelihood of ACI survival. Further studies with larger patient cohorts as well as a consensus definition of failure are needed to further refine predictors of ACI failure.

Autologous Chondrocyte Implantation for Talar Osteochondral Lesions: Comparison Between 5-Year Follow-Up Magnetic Resonance Imaging Findings and 7-Year Follow-Up Clinical Results

Autologous chondrocyte implantation (ACI) is an established surgical procedure that has provided satisfactory results. The aim of the present study was to correlate the clinical outcomes of a series of 20 patients treated by ACI at a 7-year follow-up examination with the magnetic resonance imaging (MRI) T2-mapping 5-year follow-up findings. We evaluated 20 patients using the American Orthopaedic Foot and Ankle Society (AOFAS) score preoperatively and the established follow-up protocol until 87.2 ± 14.5 months. MRI T2-mapping sequences were acquired at the 5-year follow-up examination. At the MRI examination (60 ± 12 months), the mean AOFAS score improved from 58.7 ± 15.7 to 83.9 ± 18.4. At the final follow-up examination at 87.2 ± 14.5 months, the AOFAS score was 90.9 ± 12.7 (p = .0005). Those patients who experienced an improvement between 5 and 7 years after surgery had a significant greater percentage of T2-map value of 35 to 45 ms (hyaline cartilage) compared with those patients who did not improve (p = .038). MRI T2 mapping was shown to be a valuable tool capable of predicting reproducible clinical outcomes after ACI even 7 years after surgery. The quality of the regenerated tissue and the degree of defect filling became statistically significant to the clinical results at the final follow-up examination.

hWJECM-Derived Oriented Scaffolds with Autologous Chondrocytes for Rabbit Cartilage Defect Repairing

Previously, we synthesized an articular cartilage extracellular matrix (ECM)-derived oriented scaffold for cartilage tissue engineering, which was biomimetic in terms of structure and biochemical composition. However, the limit resource of the cartilage-derived ECM is a hindrance for its application. In this study, we developed a new material for cartilage tissue engineering-human umbilical cord Wharton's jelly-derived ECM (hWJECM). The hWJECM has an abundant resource and similar biochemistry with cartilage ECM, and the use of it is not associated with ethical controversy. We adopted the method previously used in cartilage ECM-derived oriented scaffold preparation to generate the oriented hWJECM-derived scaffold, and the scaffold properties were tested in vitro and in vivo. The three-dimensional scaffold has a porous and well-oriented structure, with a mean pore diameter of ∼104 μm. Scanning electron microscopy and cell viability staining results demonstrated that the oriented scaffold has good biocompatibility and cell alignment. In addition, we used functional autologous chondrocytes to seed the hWJECM-derived oriented scaffold and tested the efficacy of the cell-scaffold constructs to repair the full-thickness articular cartilage defect in a rabbit model. Defects of 4 mm diameter were generated in the patellar grooves of the femurs of both knees and were implanted with chondrocyte-scaffold constructs (group A) or scaffolds alone (group B); rabbits with untreated defects were used as a control (group C). Six months after surgery, all defects in group A were filled completely with repaired tissue, and most of which were hyaline cartilage. In contrast, the defects in group B were filled partially with repaired tissue, and approximately half of these repaired tissues were hyaline cartilage. The defects in group C were only filled with fibrotic tissue. Histological grading score of group A was lower than those of groups B and C. Quantification of glycosaminoglycan indicated that newly formed cartilage in group A rabbits was comparable with normal cartilage. In conclusion, hWJECM-derived oriented scaffolds loaded with autologous chondrocytes induced cartilage repair in rabbit knees, which was comparable with native cartilage in terms of macroscopic view, microstructure, and biochemical composition.

Correlation of MRI Appearance of Autologous Chondrocyte Implantation in the Ankle with Clinical Outcome

The objective of this study was to characterize magnetic resonance imaging (MRI) findings and correlate with clinical results in patients who underwent autologous chondrocyte implantation (ACI) of osteochondral lesions of the talus (OLT).

METHODS

Twenty-four grafts were evaluated at a mean 65.8 months after ACI for OLT. MRI was performed on a 1.5-T GE scanner using multiple sequences. Graft appearance was compared with preoperative MRI and evaluated for 6 criteria: defect fill, surface regularity, signal pattern, bone marrow edema, subchondral plate irregularity, and presence of cystic lesions. Clinical outcome was measured with the American Orthopaedic Foot and Ankle Society (AOFAS) clinical outcome score.

RESULTS

Of 24 grafts, 22 (92%) demonstrated >75% defect fill. Eighteen (75%) had a mildly irregular and 6 (25%) had a moderately irregular articular surface. The signal pattern of the repair tissue was heterogenous in 23 (96%); 14 (58%) layered and 9 (38%) mottled. Fourteen grafts (58%) showed decreased amount of bone marrow edema while 4 (17%) had no change and 5 (21%) had an increase in the amount of bone marrow edema. The subchondral bone plate was abnormal in most grafts, with focal defects seen in 10, slight depression in 7, and both in 5. Seven had an increase in cystic lesions while the others had no change, decrease or no cysts seen. Mean postoperative AOFAS score was 87.5 with mean improvement of 39.4.

CONCLUSIONS

At 66-month mean follow-up, MRI appearance of the ACI grafts show imaging abnormalities but demonstrate good clinical results. While MRI is an important tool in the postoperative assessment of ACI grafts, the various variations from a normal/nonoperative ankle must be interpreted with caution.

Evaluation and Management of Osteochondral Lesions of the Talus

Osteochondral lesions of the talus are common injuries that affect a wide variety of active patients. The majority of these lesions are associated with ankle sprains and fractures though several nontraumatic etiologies have also been recognized. Patients normally present with a history of prior ankle injury and/or instability. In addition to standard ankle radiographs, magnetic resonance imaging and computed tomography are used to characterize the extent of the lesion and involvement of the subchondral bone. Symptomatic nondisplaced lesions can often be treated conservatively within the pediatric population though this treatment is less successful in adults. Bone marrow stimulation techniques such as microfracture have yielded favorable results for the treatment of small (<15 mm) lesions. Osteochondral autograft can be harvested most commonly from the ipsilateral knee and carries the benefit of repairing defects with native hyaline cartilage. Osteochondral allograft transplant is reserved for large cystic lesions that lack subchondral bone integrity. Cell-based repair techniques such as autologous chondrocyte implantation and matrix-associated chondrocyte implantation have been increasingly used in an attempt to repair the lesion with hyaline cartilage though these techniques require adequate subchondral bone. Biological agents such as platelet-rich plasma and bone marrow aspirate have been more recently studied as an adjunct to operative treatment but their use remains theoretical. The present article reviews the current concepts in the evaluation and management of osteochondral lesions of the talus, with a focus on the available surgical treatment options.

Outcome of combined autologous chondrocyte implantation and anterior cruciate ligament reconstruction

BACKGROUND

Instability of the knee joint, after anterior cruciate ligament (ACL) injury, is contraindication to osteochondral defect repair. This prospective study is to investigate the role of combined autologous chondrocyte implantation (ACI) with ACL reconstruction.

MATERIALS AND METHODS

Three independent groups of patients with previous ACL injuries undergoing ACI were identified and prospectively followed up. The first group had ACI in combination with ACL reconstruction (combined group); the 2(nd) group consisted of individuals who had an ACI procedure having had a previously successful ACL reconstruction (ACL first group); and the third group included patients who had an ACI procedure to a clinically stable knee with documented nonreconstructed ACL disruption (No ACL group). Their outcomes were assessed using the modified cincinnati rating system, the Bentley functional (BF) rating system (BF) and a visual analog scale (VAS).

RESULTS

At a mean followup of 64.24 months for the ACL first group, 63 months for combined group and 78.33 months for the No ACL group; 60% of ACL first patients, 72.73% of combined group and 83.33% of the No ACL group felt their outcome was better following surgery. There was no significant difference demonstrated in BF and VAS between the combined and ACL first groups. Results revealed a significant affect of osteochondral defect size on outcome measures.

CONCLUSION

The study confirms that ACI in combination with ACL reconstruction is a viable option with similar outcomes as those patients who have had the procedures staged.

Advances in the Surgical Management of Articular Cartilage Defects: Autologous Chondrocyte Implantation Techniques in the Pipeline

OBJECTIVE

The purpose of this review is to gain insight into the latest methods of articular cartilage implantation (ACI) and to detail where they are in the Food and Drug Administration approval and regulatory process.

DESIGN

A PubMed search was performed using the phrase "Autologous Chondrocyte Implantation" alone and with the words second generation and third generation. Additionally, clinicaltrials.gov was searched for the names of the seven specific procedures and the parent company websites were referenced.

RESULTS

Two-Stage Techniques: BioCart II uses a FGF2v1 culture and a fibrinogen, thrombin matrix, whereas Hyalograft-C uses a Hyaff 11 matrix. MACI uses a collagen I/III matrix. Cartipatch consists of an agarose-alginate hydrogel. Neocart uses a high-pressure bioreactor for culturing with a type I collagen matrix. ChondroCelect makes use of a gene expression analysis to predict chondrocyte proliferation and has demonstrated significant clinical improvement, but failed to show superiority to microfracture in a phase III trial. One Step Technique: CAIS is an ACI procedure where harvested cartilage is minced and implanted into a matrix for defect filling.

CONCLUSION

As full thickness defects in articular cartilage continue to pose a challenge to treat, new methods of repair are being researched. Later generation ACI has been developed to address the prevalence of fibrocartilage with microfracture and the complications associated with the periosteal flap of first generation ACI such as periosteal hypertrophy. The procedures and products reviewed here represent advances in tissue engineering, scaffolds and autologous chondrocyte culturing that may hold promise in our quest to alter the natural history of symptomatic chondral disease.