Arthroscopic Autologous Chondrocyte Implantation in Osteochondral Lesions of the Talus

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1 AJSM PreView, published on January 28, 2008 as doi: / Arthroscopic Autologous Chondrocyte Implantation in Osteochondral Lesions of the Talus Surgical Technique and Results Sandro Giannini,* MD, Roberto Buda, MD, Francesca Vannini, MD, Francesco Di Caprio, MD, and Brunella Grigolo, MD From University of Bologna, Rizzoli Orthopaedic Institute, Bologna, Italy Background: Autologous chondrocyte implantation (ACI) in the ankle was considered up to now an extremely technically demanding surgery with considerable morbidity for the patients. Hypothesis: Hyalograft C scaffold allows arthroscopic ACI, thanks to a specifically designed instrumentation. Study Design: Case series; Level of evidence, 4. Methods: Forty-six patients with a mean age of 31.4 years (range, 20-47) underwent operation from 2001 to They had posttraumatic talar dome lesions, type II or IIA. In the first step of surgery, an ankle arthroscopy was performed, with cartilage harvest from the detached osteochondral fragment or from the margins of the lesion. Chondrocytes were cultured on a Hyalograft C scaffold. In the second step of surgery, the Hyalograft C patch was arthroscopically implanted into the lesion, with a specifically designed instrumentation. Lesions >5 mm deep were first filled with autologous cancellous bone. Patients were evaluated clinically with the American Orthopaedic Foot and Ankle Society (AOFAS) score preoperatively and at 12 and 36 months after surgery. At a mean time interval of 18 months, the first 3 patients underwent a second-look arthroscopy with cartilage harvest from the implant and histological examination. Results: The mean preoperative AOFAS score was 57.2 ± At the 12-month follow-up, the mean AOFAS score was 86.8 ± 13.4 (P <.0005), while at 36 months after surgery, the mean score was 89.5 ± 13.4 (P <.0005). Clinical results were significantly related to the age of patients and to previous operations for cartilage repair. The results of the histological examinations revealed hyaline-like cartilage regeneration. Conclusions: The Hyalograft C scaffold and the specifically designed instrumentation allowed arthroscopic implantation of chondrocytes, with excellent clinical and histological results. Keywords: ankle; osteochondral lesion; autologous chondrocyte implantation; arthroscopy; instrumentation Osteochondral lesions of the talus represent a significant problem for the foot surgeon. 19,28,29 Joint cartilage is a highly specialized and multitask tissue. Because of its poor reparative capability, injuries may be irreversible and, as a consequence, may lead to chronic pain, joint swelling, interruption of sport activities, and osteoarthritis. 5,21 *Address correspondence to Sandro Giannini, MD, University of Bologna, Rizzoli Orthopaedic Institute, Via G.C. Pupilli 1, 40136, Bologna, Italy ( giannini@ior.it). No potential conflict of interest declared. The American Journal of Sports Medicine, Vol. X, No. X DOI: / American Orthopaedic Society for Sports Medicine The main goal of autologous chondrocyte implantation (ACI) is to repair the osteochondral lesion with newly regenerated hyaline cartilage. Autologous chondrocyte implantation was first used in the treatment of osteochondral lesions of the knee, 3,6,26 becoming increasingly popular, and later was successfully applied to the ankle. 2,8,10,24,30 Nevertheless, in all the cases described up to now, the surgical technique was extremely technically demanding open surgery; malleolar osteotomy and a periosteal flap sutured to the surrounding cartilage were required, with considerable morbidity for the patient. A biodegradable scaffold for cell support and proliferation has been developed by tissue engineering. 1 The scaffold used is based entirely on the benzylic ester of hyaluronic acid (HYAFF 11), produced by Fidia Advanced 1 Copyright 2008 by the American Orthopaedic Society for Sports Medicine.

2 2 Giannini et al The American Journal of Sports Medicine Biopolymers Laboratories (Abano Terme, Italy). This nonwoven 3-dimensional structure consists of a network of 10- to 15-μm-thick fibers with interstices of variable sizes that constitute an optimal physical support to allow cell-to-cell contact, cluster formation, and extracellular matrix deposition. 4 This hyaluronic acid scaffold was already used for ACI in the knee, thus avoiding open surgery and the use of periosteal flap, with consequent reduced patient morbidity, time, and costs of surgery ,23,27 The technique described for the knee was modified to be used in the ankle joint, thanks to the development of specifically designed instrumentation. The objective of this article is to describe an original arthroscopic procedure for ACI in the ankle by using chondrocytes cultured on Hyalograft C, with analysis of the results. MATERIALS AND METHODS From June 2001 to March 2004, 46 consecutive patients with focal talar dome osteochondral lesions were treated with arthroscopic ACI, using a hyaluronan-based 3-dimensional scaffold (Hyalograft C). The treatment was indicated in cases of symptomatic focal osteochondral lesions of the talar dome, classified as chronic type II (0-5 mm deep) or IIA (>5 mm deep), 7 in patients younger than 50 years of age. Exclusion criteria were age younger than 15 years and older than 50 years, arthritis of the ankle joint, kissing lesions, and rheumatoid arthritis. Instability or axial defects were corrected when present. Patient Data Twenty-nine men and 17 women with a mean age of 31.4 years (range, 20-47) underwent the same surgical procedure. All the patients were affected by posttraumatic talar dome lesions, type II or IIA. 7 All the patients were able to recall an ankle sprain between 6 months and 5 years before surgery. No osteochondritis dissecans lesions were included in the study. The lesion was located medially in 35 cases (76.1%); in 7 cases, it was lateral (15.2%); and in 4 cases, it was double (medial plus lateral) (8.7%). The mean size of the lesion was 1.6 cm 2 (range, cm 2 ). Three patients had a previous ankle fracture. Sixteen patients were previously operated with microfractures (7 cases), arthroscopic ankle debridement (4 cases), chondrectomy (2 cases), drilling (1 case), mosaicplasty (1 case), or lateral ligament reconstruction (1 case). Twenty-nine patients practiced a sport activity: contact sports (soccer, basketball) in 16 cases and noncontact sports (volleyball, tennis, swimming, cycling, ballet, aerobics) in 13 cases. They practiced sports at a recreational level in 25 cases, while 4 patients were professionals. All the patients underwent physical therapy and rehabilitation for 3 to 6 months without being able to resume previous sport activity because of ankle pain, swelling, or stiffness. Seven patients had associated procedures: cheilectomy in 6 cases and first metatarsal osteotomy for cavus foot correction in 1 case. In 5 cases with a lesion deeper than 5 mm (type IIA), the defect was filled by autologous cancellous bone harvested from the proximal tibial metaphysis, during the second-step surgery. Preoperative Evaluation The preoperative evaluation included acquiring a complete history of the patient and a physical and radiographic examination. The history of the likely cause of trauma to the ankle and previous failed treatment attempts were recorded. The ankle was checked for instability, malalignment, and range of motion. A standard radiographic examination, including anteroposterior and lateral weightbearing views of both ankles and magnetic resonance images of the affected ankle, was conducted. Surgical Technique Surgical treatment consisted of 2 steps; in both steps, the patient was placed in the supine position on the operating table with a tourniquet on the proximal thigh. In the first procedure, anterolateral and anteromedial arthroscopic approaches to the ankle were used. The lesion was detected and evaluated, and the status of the surrounding cartilage and underlying bone was checked, as well as the status of the opposing chondral surface. The lesion was accurately shaved and the pathologic tissue removed. The surrounding bone was checked and removed if pathologic until good quality bone was found. If there was a detached osteochondral fragment, it was removed and used for culture, as the cells from the detached osteochondral fragment were demonstrated to be adequate for transplant. 9 Otherwise, a small slice of cartilage tissue was harvested from the margin of the lesion or from the anterior margin of the tibia and used for cell culture. A standard closure was performed by using 3-0 reabsorbable stitches. Postoperative care consisted of early passive motion with progressive weightbearing as tolerated. The chondrocytes were expanded in the laboratory and then seeded on the scaffold. In the second-step arthroscopy, custom-made specific instrumentation that 2 of the authors (S.G. and R.B.) participated in designing was used for implantation (Citieffe, Calderara di Reno, Bologna, Italy). This consisted of an 8-mm-diameter and 111-mm-long stainless steel cannula with a window on 1 side and a positioner specifically designed to slide inside the cannula delivering the scaffold directly to the site of the lesion. Anterolateral and anteromedial arthroscopic approaches of the ankle were used as in the first procedure. The lesion was detected and accurately measured. The hyaluronic acid scaffold was cut to the same size as the lesion (Figure 1). The cannula was inserted through the arthroscopic approach nearest to the lesion (Figure 2). Saline was removed from the joint. The hyaluronic acid scaffold was applied to the tip of the positioner (Figure 3) and driven into the cannula. The progression of the scaffold inside the cannula was easily checked through the window of the cannula. The scaffold was driven completely inside and

3 Vol. X, No. X, XXXX Arthroscopic ACI in Osteochondral Lesions of the Talus 3 Figure 2. Arthroscopic view of the cannula inserted through the arthroscopic access nearest to the lesion. Figure 1. The hyaluronic acid scaffold is cut by a specific sizer. applied to the lesion with the help of a probe (Figure 4). The cannula was then removed, and the scaffold was made to fill the lesion exactly by using an appropriate flattened probe (Figure 5). Under arthroscopic control, the ankle was moved from flexion to extension to check the stability of the implant. Standard closure was performed by 1 suture thread. The whole second-step procedure was recorded to take 30 to 45 minutes per patient. Postoperative Treatment Continuous passive motion (CPM) was advised the day after surgery. During the first days, CPM was maintained low (1 cycle/min) for an average of 6 to 8 hours a day. The range of motion was gradually increased according to pain tolerance; CPM was maintained for 3 weeks. Walking with crutches and no weightbearing on the affected ankle was advised. Partial weightbearing increasing to full weightbearing was permitted from 6 to 8 weeks after surgery, and at 4 months after surgery, low-impact sport activity could be resumed. After 10 to 12 months, running and progressive training for high-impact activities, such as tennis and soccer, were permitted. Figure 3. The hyaluronic acid self-adhesive scaffold is applied to the tip of the positioner. Patient Evaluation Patients were evaluated clinically with the American Orthopaedic Foot and Ankle Society (AOFAS) score preoperatively and at 12 and 36 months after surgery. Results were rated as follows: excellent, 90 to 100; good, 80 to 89; fair, 60 to 79; and poor, <60. Results were analyzed by age, presence of double lesion, size and location of the lesion, past interventions for cartilage repair, and need for bone implantation. Figure 4. The positioner is driven into the cannula, and then the scaffold is applied to the lesion with the help of a probe.

4 4 Giannini et al The American Journal of Sports Medicine TABLE 1 Results Analyzed by Type of Lesion Patients (n) Preoperative 36 Months Single ± ± 11.6 Double ± ± 26.0 Size <2 cm ± ± 13.1 Size >2 cm ± ± 14.0 Medial ± ± 12.2 Lateral ± ± 4.3 No bone grafting ± ± 13.3 Bone grafting ± ± 15.0 Figure 5. The scaffold is made to fill the lesion exactly with the help of a flattened probe. At a mean time interval of 18 months (range, 15-22), the first 3 patients underwent a second-look arthroscopy. The implant site was inspected and evaluated using the International Cartilage Repair Society (ICRS) visual scoring system, 15 including the degree of defect repair, graft integration to adjacent normal articular surface, and gross appearance. Biopsy specimens from the central portion of the repaired lesion were obtained for histological and immunohistological analysis. The histological analysis was blinded, and the biopsy specimens were evaluated independently by 2 observers. Statistical Analysis All continuous data were expressed in terms of mean and standard deviation of the mean. The paired t test was used to determine any significant differences between the score obtained at set intervals before and after ACI. The Wilcoxon nonparametric test was used to confirm the t test result. The Mann-Whitney test, evaluated by the Monte Carlo method for small samples, was performed to test hypotheses about means of different groups. Pearson correlation was performed to investigate the relationships between continuous variables. For all tests, P <.05 was considered significant. Statistical analysis was carried out via SPSS software version 14.0 (SPSS Inc, Chicago, Ill). RESULTS No intraoperative or postoperative complications were reported. The mean preoperative AOFAS score was 57.2 ± At the 12-month follow-up, the mean AOFAS score was 86.8 ± 13.4 (P <.0005), while at 36 months after surgery, the mean score was 89.5 ± 13.4 (P <.0005). None of the patients were lost to follow-up. The overall scores at 36 months were 25 excellent (55.0%), 13 good (27.5%), 6 fair (12.5%), and 2 poor (5%). Among the 6 cases rated as fair, 3 were previously operated with microfractures, 1 with chondrectomy, and 1 with mosaicplasty; 1 patient had a first metatarsal osteotomy. Of the 2 patients rated as poor, 1 was a 35-year-old patient with a double lesion, already treated with microfractures; the other was a 41-year-old patient with no associated lesions or previous interventions. A significant relationship was found between the age of patients and the clinical outcome; in particular, we found a significant negative correlation between the age and the AOFAS score at 36 months follow-up (P =.05, R =.23). Previous interventions for cartilage repair negatively affected the final outcome: a significant difference was found between never-treated and already-treated patients in the AOFAS score at 12 months follow-up (91.3 ± 9.3 vs 72.6 ± 14.8; P <.0005) and at 36 months follow-up (94.2 ± 8.9 vs 74.6 ± 14.7; P <.0005), although the 2 groups showed similar preoperative AOFAS scores (56.7 ± 14.6 vs 58.5 ± 13.7). No significant relationship was found between the clinical outcomes and the presence of a double lesion, the size of the single lesion more or less than 2 cm 2, the location of the lesion (medial or lateral), or the need for cancellous bone implantation (type IIA lesions) (Table 1). Among the patients who practiced sports, 20 resumed the same sport at the same level, 3 resumed the same sport at a lower level, 2 shifted to a noncontact sport, and 4 patients gave up sports. The 4 professionals were all able to resume their previous activity. A detailed description of patient data and results is provided in Table 2. Second-Look Arthroscopies and Biopsies The 3 second-look arthroscopies revealed a continuous and intact cartilage layer in all 3 cases (Figure 6); in 2 of the 3 case, the integration to border zone was complete, with demarcated border <1 mm. In 1 case slight cartilage softening at the site of implantation was noted (Table 3). The histological evaluation of the biopsy specimens highlighted the presence of all the components of hyaline cartilage, and the tissues showed various degrees of tissue remodeling. The content of glycosaminoglycans was revealed by safranin-o staining (Figure 7A), which also showed the presence of collagen fibers mainly localized in the superficial zone. An initial columnarization of the chondrocytes was observed in the deep layers. Collagen type II was positive mainly in the extracellular matrix (Figure 7B).

5 Vol. X, No. X, XXXX Arthroscopic ACI in Osteochondral Lesions of the Talus 5 TABLE 2 Patient Data and Results a AOFAS Score Patient Site Size (cm 2 ) Age Preoperative 12 Months 36 Months Previous Interventions Associated Procedures Preop Sports Level Postop Sports 1 L Ballet Recreational Same 2 M Microfractures Soccer Recreational None 3 M Microfractures Soccer Recreational Other 4 M Debridement Cheilectomy None 5 M Soccer Recreational Same 6 M Aerobic Professional Same 7 M Microfractures None 8 M None 9 M Debridement Tennis Recreational Lower level 10 M Volleyball Recreational Same 11 L Bone grafting Soccer Recreational Same 12 D Microfractures None 13 M Microfractures None 14 M Soccer Professional Same 15 M None 16 M st metatarsal osteotomy Tennis Recreational None 17 M Cheilectomy Soccer Recreational Lower level 18 M None 19 M Microfractures Bone grafting None 20 M Chondrectomy Bone grafting Soccer Professional Same 21 M Basketball Recreational Same 22 M Bone grafting Soccer Recreational Other 23 L Swimming Recreational Same 24 M Chondrectomy Soccer Recreational None 25 M None 26 L Soccer Recreational Lower level 27 M Basketball Recreational Same 28 M Volleyball Recreational Same 29 M Debridement None 30 M Drilling None 31 M Lateral ligament reconstruction Soccer Recreational Same 32 M Cheilectomy Tennis Recreational Same 33 M Mosaicoplasty None 34 M Cheilectomy None 35 L Volleyball Recreational Same 36 M None 37 M Cycling Recreational Same 38 M Bone grafting None 39 M Cheilectomy Soccer Recreational Same 40 D Microfractures None 41 D Debridement Tennis Recreational None 42 M Cycling Recreational Same 43 M Swimming Recreational Same 44 D Cheilectomy None 45 L Soccer Professional Same 46 L Soccer Recreational Same a AOFAS, American Orthopaedic Foot and Ankle Society; L, lateral; M, medial; D, double.

6 6 Giannini et al The American Journal of Sports Medicine Figure 6. Second-look arthroscopy at 22 months follow-up. The cartilage layer in the site of previous implant in the medial portion of the talar dome is continuous and intact. TABLE 3 Findings at Second-Look Arthroscopies and Biopsies a Size Interval From ICRS ICRS of the Implantation Visual Repair Case Lesion (cm 2 ) (months) Score Category Histology Normal Hyaline-like Nearly Hyaline-like normal Nearly Hyaline-like normal a ICRS, International Cartilage Repair Society. Figure 7. Histological and immunohistological observations of the repair tissue from a representative patient treated with autologous chondrocyte transplantation at 22 months follow-up. A, the safranin-o staining shows a typical cartilaginous structure. B, immunostaining for type II collagen in the patient sample shows a positivity that is diffused in the extracellular matrix. Type II collagen was developed using new fuchsin (red is positive stain). DISCUSSION The present study is a prospective case series and describes an original procedure for the arthroscopic treatment of osteochondral lesions of the ankle, with analysis of the results. It was not possible to conduct a controlled randomized clinical trial because it would require a very large number of patients. Moreover, when comparing a conventional open ACI with an arthroscopic ACI, differences in the clinical outcome could be influenced by a number of variables. Another limitation of the study was the lack of an imaging follow-up study. This could be the aim for further studies. The ideal technique for a chondral defect repair would generate a repair tissue with biomechanical properties closely matching normal hyaline articular cartilage. Autologous chondrocyte implantation is considered to provide a repair tissue that closely approximates the physical characteristics (stiffness) of the cartilage in the majority of cases and may make it more durable in the long term compared with fibrocartilage. 25 The excellent durability of results obtained by ACI over time is well established and contrasts sharply with the long-term results reported for marrow-stimulating techniques (such as abrasion, drilling, or microfractures), which provide a fibrocartilaginous repair tissue. 14,22 Peterson et al 25 underlined the importance of patient status at 2 years as an indicator of future outcome because patients who obtained good results at 2 years were able to maintain the results in the long term. This is also consistent with the findings reported by Henderson et al, 13 who stated that fibrocartilage repair techniques have a higher likelihood of becoming symptomatic earlier compared with ACI repair, and those of Nehrer et al, 20 who reported a more fibrous nature of the repairs that failed before 18 months. In a multicenter, comparative, prospective evaluation of 413 arthroscopic resurfacing procedures (mosaicplasty, drilling, abrasion arthroplasty, and microfracture), Hangody et al 11 demonstrated that mosaicplasty gave a more favorable clinical outcome in the long-term follow-up than the other 3 techniques because of its ability to transplant viable hyaline cartilage in the knee as well as in the ankle. Otherwise considerable drawbacks of mosaicplasty are represented by donor-site morbidity, by the presence of dead spaces between the circular grafts that are left to heal as fibrocartilage, and by the frequent need for a malleolar osteotomy. 10 Autologous chondrocyte implantation in the ankle has been considered up to now as an extremely technically

7 Vol. X, No. X, XXXX Arthroscopic ACI in Osteochondral Lesions of the Talus 7 demanding operation because of the difficulty in managing liquid chondrocyte culture solution and the need to create a hermetic periosteal suture, especially in such a narrow space as the ankle. 2,8,10,24,30 Thanks to improvements in biological engineering, the use of 3-dimensional hyaluronic acid support has enhanced considerably the applicability of ACI. Autologous chondrocyte implantation has already been performed arthroscopically in the knee ,23,27 The arthroscopic application of ACI in the femoral condyles is favorable because the lesion is directly in front of the arthroscopic portal, thus facilitating the application of the scaffold. This is, to our knowledge, the first report describing a completely arthroscopic ACI procedure in the ankle joint. To perform a completely arthroscopic ankle lesion repair, with the tangential perspective and the extremely narrow space available, a specifically designed instrumentation was necessary to permit an easy and rapid positioning of the scaffold inside the lesion. The technique we reported has the advantage of a dramatic reduction in surgical trauma because it avoids open surgery, the need for periosteal harvest, the necessity of a malleolar osteotomy, and a subsequent operation for hardware removal. The results obtained with the described procedure were excellent or good in more than 80% of cases and did not show any negative tendency over time. Unfavorable factors were found to be the age of the patients and previous surgery for cartilage repair. The presence of a double lesion, the size and location of the lesion, and the need for bone implantation were not proven to significantly affect the final outcome (this could be due to the small number of patients in these subgroups). Resumption of sports was achieved in 86% of the patients. Patients who gave up sports or who changed the type or level of activity all practiced at a recreational level and specifically declared that their choice was not obliged but fear of reinjury played a role in their decision. A restricted number of small biopsies were performed because of the obvious difficulties in obtaining such material; therefore the observed results might be due to a sampling error that underrepresents a possibly more robust remodeling repair response. However, in the samples analyzed, there was evidence of the formation of a new tissue that displayed varying degrees of organization with some fibrous and fibrocartilaginous features. Long-term followup investigations, supported also by MRI analysis, are needed to verify if, once all the remodeling processes are completed, the newly formed tissue will acquire the more typical features of articular cartilage. 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