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From the Department of Orthopaedic Surgery, University Hospital of Freiburg, Freiburg, Germany
* Address correspondence to Peter Cornelius Kreuz, MD, Department of Orthopaedic Surgery, Albert Ludwig University of Freiburg, Hugstetter Str. 55, 79106 Freiburg, Germany (e-mail: kreuz{at}ch11.ukl.uni-freiburg.de).
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ABSTRACT |
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 TOP ABSTRACT INTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
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Hypothesis: Osteochondral autografting can produce significant clinical improvement and a high rate of healing of osteochondral defects of the talus that have failed arthroscopic treatment.
Study Design: Cohort study; Level of evidence, 4.
Methods: Between 1998 and 2003, 35 patients (18 men, 17 women) with osteochondral talar lesions for which arthroscopic excision, curettage, and drilling had failed, underwent mosaicplasty with an osteochondral graft harvested from the ipsilateral talar articular facet. A malleolar osteotomy or a tibial wedge osteotomy was used for central or posterior lesions that could not otherwise be reached. The mean age of the patients was 30.9 years, and the mean follow-up was 48.9 months.
Results: The American Orthopaedic Foot and Ankle Society Ankle Hindfoot scale score in patients without osteotomy rose by 39 points (P = .0001); with malleolar osteotomy, by 30.1 points (P = .017); with tibial wedge osteotomy, by 34.9 points (P = .0002); and with the posterolateral approach, by 32 points. The Wilcoxon test revealed a significant difference between patients without and with osteotomy (P 
.027) and between patients with malleolar and tibial wedge osteotomies (P = .046). There were no patients with nonunion or malunion in the osteotomy groups. The score values corresponded with the subjective patient evaluation. The Spearman coefficient of correlation was .89.
Conclusion: Osteochondral autografting with tibial wedge osteotomy is a good alternative to malleolar osteotomy in osteochondral talar lesions that have failed arthroscopic treatment and that cannot be reached in spite of a forced plantar flexion of the ankle. Patients with small osteochondral lesions accessible through an anterior approach without additional osteotomy have the best prognostic factors.
Key Words: mosaicplasty • osteochondral lesion • malleolar osteotomy • tibial wedge osteotomy
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INTRODUCTION |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
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The classification of osteochondritis dissecans in 4 stages by Berndt and Harty3 is commonly used.6,18,24 Loomer and Fischer21 have added a fifth stage for cystic lesions.21
Nonoperative treatment is indicated for grade 1 and 2 lesions and includes immobilization, restriction of weight-bearing activity, and physiotherapy.14
Surgical intervention is recommended if nonoperative treatment is unsuccessful and as initial treatment for grade 3 and 4 lesions.13,15,19
Before arthroscopic surgery became the standard in the treatment of osteochondral talar lesions, conventional therapies, such as wound debridement, microfractures, and fragment refixation, were performed by arthrotomy.1,3,10,22,35
Anterolateral,17 anteromedial,8 posterolateral,21 and posteromedial32,33 approaches, as well as medial malleolar and fibula osteotomies,8,11,26 are described in the literature.30
Recent studies have shown that arthroscopic surgery may be advantageous in the treatment of small defects and stable osteochondral lesions, but favorable results have been less predictable for large and unstable osteochondral defects treated arthroscopically.14,16 Hangody and Füles15 treated these lesions with osteochondral transplantation and reported a 10-year follow-up of 76 patients with about 94% good and excellent results.
Because most of the osteochondral lesions, especially medial lesions, are located posteriorly on the dome of the talus, the arthrotomy has to be combined with an additional osteotomy.12 The malleolar osteotomy has become a standard approach for these lesions.31 However, it is an invasive method with risk of malunion, nonunion, or incongruency, leading to secondary osteoarthritis and deterioration of the result.2,12 In cases of symptomatic hardware, a second procedure may be necessary to remove the screws from the malleolus.
Therefore, we started to access osteochondral talar lesions in the middle and posterior areas of the talar dome with a new anterior approach by temporary removal and replacement of a tibial pyramidal bone block. The osteochondral graft is harvested from a low weightbearing area of the talar articular facet.29
Although we believe that the primary treatment of osteochondral lesions of the talus should be arthroscopic, we reserve osteochondral autografting for cases that have failed arthroscopic surgery. Historically, autogenous osteochondral grafting has been reported primarily for lesions of the knee. Only one large series using this technique in the talus has been reported.15 Our purpose was to report our experience with osteochondral autografting for lesions of the talus that had failed primary arthroscopic management. We use several different surgical approaches, depending on the location of the lesion on the talar dome. During the study, we developed a new technique of tibial wedge osteotomy to replace medial malleolar osteotomy for exposing lesions of the central and posterior talar domes that could not be approached without an osteotomy, so a secondary goal of the study was to describe the technique and report the results of this osteotomy.
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MATERIALS AND METHODS |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
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Thirty patients had experienced a previous trauma with inversion of the foot. Of these patients, 21 underwent primarily a nonoperative treatment with anti-inflammatory medication and temporary dressing to stabilize the joint. Therefore, the time between the onset of symptoms before the diagnosis of osteochondritis dissecans and the first surgical intervention was 23.8 months (range, 3–84 months). Of the 5 patients without trauma, 3 had a body mass index greater than 30 kg/cm2.
At the time of our initial examination, a standard radiograph and an MRI scan were performed on all of the 35 patients, and a CT scan was performed on 2 patients. Twenty-nine osteochondral defects were classified as stage 4 lesions and 6 as stage 3 lesions, according to the classification system of Loomer (Table 1
).21 The mean lesion size was 6.3 mm (4 x 4 mm, 23 x 6 mm, 7 x 8 mm, 1 x 10 mm). Four lesions were located anteromedial; 16, midmedial; 11, posteromedial; 1, central; 2, anterolateral; and 1, in the posterolateral region of the talar dome.
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Inclusion and Exclusion Criteria
Inclusion criteria were joint stability, lack of signs of extensive joint degeneration, an age between 18 and 45 years, and osteochondral lesions of stage 3 and 4 for which previous arthroscopic treatment was not successful. To verify the location of the lesions and choose the appropriate surgical approach, all cases began with a diagnostic arthroscopy.
Exclusion criteria were infection, osteochondral lesions in the early stages 1 and 2, metabolic diseases, axial mal-positioning, joint instability, degeneration, foot deformities with need of correction, and osteochondral talar lesions without previous arthroscopic treatment.
Groups
The surgical approach for osteochondral transplantation was selected according to the location of the defect on the talar dome. The patients therefore were divided into 4 groups (Table 1
). From 1998 to December 1999, we employed a medial malleolar osteotomy to access central and posterior talar lesions. From that time forward, we used a new approach for the same indication group: the tibial wedge osteotomy.
With respect to the parameters age, defect size, defect location, and preoperative American Orthopaedic Foot and Ankle Society Ankle Hindfoot scale (AOFAS) score, the 4 groups were relatively homogeneous and comparable (Tables 1 and 2).
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The preoperative workup included radiographs and MRI, as described before, stability tests of the ankle joint, and the assessment of neurologic status.
After arthroscopic inspection and debridement of the ankle joint and measurement of the defect size and depth, the lesion was approached with a small longitudinal incision of the joint capsule.
With the ankle plantar flexed, the defect was prepared and an osteochondral graft plug, harvested from the ipsilateral talar articular facet of the osteochondritis dissecans lesion, was driven perpendicular to the talar dome into the recipient socket (Soft Delivery System, Sulzer Medica, Winterthur, Switzerland) (Figure 1A).
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On day 1, passive exercises of the ankle with limited range of motion and active isometric training were started. Toe-touch ambulation with crutches was permitted, accompanied by physical therapy. Six weeks after surgery, a radiograph was taken. In cases of good incorporation of the osteochondral graft, gradual progression from partial to full weightbearing activity was allowed. Ankle radiographs were taken after 3 months, and MRI scans were taken after 6 and 12 months.
The described technique of osteochondral transplantation and the postoperative regimen was identical in the following approaches.
Osteochondral Transplantation With Medial Malleolar Osteotomy.
Before 2000, this approach was used for central and posterior lesions that could not be reached without osteotomy.
The L-shaped incision uses the standard medial approach to the talus but extends posteriorly to the posterior edge of the malleolus. Two screw holes were predrilled for the later refixation of the malleolus. Then, an oblique osteotomy was performed with an oscillating saw (Table 3). To avoid any damage to the cartilage, the last millimeters were completed with a small osteotome, and the talar articular surface was protected with an elevator. The malleolus, which was hinged on the deltoid ligament pedicle, was retracted distally to gain wide access to the joint (Figure 2).
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).
Osteochondral Transplantation With a New Tibial Block Osteotomy.
In 2000 and thereafter, this approach was used for central and posterior lesions that could not be reached without osteotomy.31
After arthroscopic examination of the upper ankle joint, the lesion was approached by temporary removal of a bone block from the tibia, including the articular surface.31
For this purpose, a longitudinal incision of the joint capsule, including the periosteum at the anterior surface of the distal tibia, was performed. The capsular flaps and the periosteum were reflected medially and laterally from the tibia until the area of the projected bone block was exposed. The exposed area lies directly over the defect area. The tibial plafond bone block temporarily removed resembles a triangular pyramid having 3 triangular faces and a triangular base. Consequently, the depth at the vertex is 0. The line going from this point to the posterior point of the base runs in an oblique direction (Table 3; Figure 3). The anterior triangular surface, approximately 4.5 cm high and 1.5 cm wide, was marked with a pen. Two guide wires were drilled from the edges of the base in an oblique direction and therefore crossed posterior in the tibial metaphysis. An image intensifier was used to make sure that the point of crossing was posterior to the defect area. Before removal of the bone block, 2 screw holes were drilled in the tibia from anterior to posterior to achieve an exact refixation of the block after mosaicplasty (Table 3). A 10-mm-wide thin osteotome was then driven into the tibia, following the direction of the guide wires. An elevator was set into the joint space to avoid injuring the uninvolved talar articular surface. The tibial cartilage was cut with a scalpel. The removed bone fragment was wrapped in a moist compress to be replaced later.
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Afterward, the tibial bone pyramid was replaced into its original bed and fixed with 2 resorbable pins placed into the holes that were drilled before the tibial osteotomy (Table 3). Range of motion was tested to ensure that there was no gap between the tibial bone block and the surrounding tibial plafond.
Osteochondral Transplantation With Posterolateral Approach.
This approach was used for posterolateral lesions. After an arched incision over the peroneal tendons at the posterior margin of the fibula, the tendon sheath was opened and the tendons were retracted anteriorly. After the joint capsule was opened, the talar defect was identified with the foot in dorsiflexion. An additional osteotomy was not necessary. For harvesting the osteochondral graft, an additional anterior approach to the talus, as described previously, was necessary.
Statistical Analysis
The patients were evaluated before and after surgery using the AOFAS. The data were analyzed using the Wilcoxon test and categorical data by the 
2 test. P < .05 was considered significant.
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RESULTS |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
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).
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Preoperative AOFAS scoring using the ankle and hind-foot score was 54.5 of 100 points (range, 47–60). After a mean follow-up of 48.9 months, the postoperative score was 89.9 points (range, 80–100). Overall improvement between preoperative and postoperative AOFAS scores was 35.5 points on average (range, 26–48), and it was statistically significant (P .017) (Table 4). The results were independent from the age of the patients.
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. The best results were achieved by osteochondral autogenous grafting via an anterior approach without osteotomy, followed by access to the talus via tibial block osteotomy. Patients with a posterolateral approach or a malleolar osteotomy scored lower. The independent Wilcoxon test revealed a significant difference between the improvement in groups 1, 2, and 3 (groups 1 and 2: P = .003; groups 1 and 3: P = .027; groups 2 and 3: P = .046).
The score values corresponded with the subjective patient evaluation (Table 4). Better subjective results were given for a surgical treatment via an anterior approach without osteotomy (1.5), followed by the procedure with tibial block osteotomy (1.54), malleolar osteotomy (1.86), and the posterolateral approach (2.0). The Spearman coefficient of correlation was .89.
The pain score on a visual scale was 8.5 (range, 6–10) preoperatively and 1.5 (range, 1–4) postoperatively (P = .0001). There was a significant improvement in all 4 groups (P < .016).
All patients had a period of 6 weeks postoperatively with partial weightbearing (10 kg) activity. Thereafter, a standard radiograph of the ankle in 2 planes revealed incomplete osseous healing in 3 patients with tibial block osteotomy and in 2 patients with malleolar osteotomy. A second radiograph 10 weeks after surgery showed no more gap, and weightbearing activity could be increased gradually to reach full weightbearing activity approximately 12 weeks after surgery.
Radiographs after 2 years revealed no decreased joint space in the ankle, no delayed unions or nonunions, and no osteophytes on the anterior tibial plafond. Follow-up MRI scans after 1 year revealed good integration of the tibial bone block without incongruency to the surrounding tibial articular surface (Figure 4). A subchondral edema, which was still visible in 17 patients on the T2-weighted MRI images after 1 year, had disappeared completely in the further follow-up, except in 1 patient without integration of the osteochondral graft (detailed later).
Clinical examination postoperatively revealed improved range of motion, gait pattern, endurance, and muscle strength, as reflected in the AOFAS scores.
Postoperatively, there was 1 patient with a suture reaction and another patient with a temporary tingling on the dorsum of the foot. Both problems disappeared completely after 1 to 3 months. A patient in group 1 had continued ankle pain 8 months after the surgery. An MRI revealed good osseous integration of the osteochondral graft but an inhomogeneous cartilage signal. Diagnostic arthroscopy showed a soft cartilage layer without bonding to the surrounding tissue. A cartilage biopsy was taken, and the cells were cultivated in a bioengineering laboratory and transplanted into the defect area. Six months after surgery, the patient was free of pain and started engaging in sports activities (Table 5).
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Two other patients had new postoperative trauma to the ankle joint. An MRI for each patient showed only a well-integrated osteochondral graft, which did not explain the persistent pain. Arthroscopy in both patients revealed new cartilage defects different from the former transplanted talar area. One of the lesions was microfractured, and the other defect was treated with osteochondral transplantation. Both patients recovered after a mean follow-up of 3 months, and normal sports activities could be resumed 6 months after surgery (Table 5).
Apart from these complications, none of the patients was limited in the activities of daily life, and the patients stated that they would undergo the procedure again.
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DISCUSSION |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
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In 1985, Flick and Gould10 were the first to describe an anterior approach to posterior talar lesions by removing a tibial bone block. They grooved the anterior articular surface of the tibia overlying the talar lesion with a narrow gouge. The removed area of distal tibia articular surface was 8 mm deep and discarded. However, the study had no statistical analysis because of the small number of 6 patients and no long-term follow-up with regard to the development of osteoarthritis. Furthermore, the method was not suitable for larger and more posteriorly located talar lesions because the amount of bone that must be removed is significant and weakens the tibial plafond if not replaced.
In 2002, Sammarco and Makwana28 published a technique consisting of the temporary removal of a 5-sided bone block with a rectangular basis from the distal tibia and its later reinsertion. It was 10 mm wide, 20 mm deep, 30 mm high, and cut with an oscillating saw. The results from 12 patients with a 2-year follow-up were promising.
In 2000, we started our own investigations, independent from this study, using a modified approach with temporary removal of a smaller 4-sided bone pyramid of different shape (Figures 1 and 3).31 Predrilling of the tibial block for its later accurate replacement and careful, even cutting of the tibial articular cartilage with a scalpel are basic prerequisites to avoid malunion or incongruency with subsequent osteoarthritis. Avascular necrosis of the tibial block was not seen in any of our 13 patients. Chiseling of the bone block produces rough cancellous bone surfaces, promoting interdigitation during its replacement. Furthermore, the periosteum is carefully sutured over the replaced bone block to promote healing. Using resorbable pins for the refixation of the tibial bone block, a second intervention via a malleolar osteotomy to remove metal as necessary can be avoided.
The osteochondral graft plug was harvested from the medial, and in cases of 2 grafts from the medial and lateral, talar articular facet. The knee as an alternative donor remained untouched. Thus, the problem of the donor site morbidity, described in the literature as occurring in up to 15% of cases, could be excluded.12,14 During dorsiflexion and plantar flexion of the ankle, the harvest tube was set on the talus to control the donor site to be in a low weight-bearing articular talar area.29,31 According to our experience, the maximum diameter of the grafts should not exceed 6 to 8 mm. For the reconstruction of larger osteochondral lesions, grafts should be taken from the ipsilateral knee (Table 2).
From our point of view, a controlled period of partial weightbearing activity of at least 6 weeks and follow-up radiographs are of special importance for the success of the surgical intervention. Participating in weightbearing activity too soon may cause micromotion in the osteotomy gap with risk of dislocation of the refixed bone block.
The healing process of the transplanted osteochondral graft with ingrowth of capillaries from the body of the talus can take place only in the absence of motion in the subchondral bed.10 In this context, Flick and Gould stated that motion in the fracture line could have the potential of shearing off the ingrowing capillaries and halting the reparative process.3,10
We therefore monitored the incorporation of the osteochondral graft, the malleolus, and the tibial bone block 6 and 12 weeks after surgery with radiographs. An additional MRI was performed in patients with persisting symptoms. Full weightbearing activity was allowed only after evidence of good integration. To avoid a recurrence, sports activities should not be resumed until 6 months after surgery. One patient with an initially good result started engaging in her usual sports activities, such as jogging, volleyball, and dancing, 4 months after surgery. After 6 months, the pain in the ankle joint increased again, and a control MRI showed no integration of the osteochondral graft.
As listed in Table 1, there are variations in the surgical details, depending on the lesion location. The anterior approach is indicated for anterior lesions and the posterolateral approach for distant posterior lesions. The medial malleolar osteotomy and tibial wedge osteotomy are used for lesions in the more central and posterior locations. Regarding mean age, classification, mean defect size, and preoperative AOFAS score, both groups were relatively homogeneous. The independent Wilcoxon test revealed significant difference between the improvement of both groups (P = .046). The great advantage of the tibial wedge osteotomy is the possibility to vary the approach depending on the lesion location. Thus, the harvest tube and the osteochondral graft plug can be set perpendicular to the defect area. When using the malleolar osteotomy, the instruments can be set only in an oblique angle to the talar dome, avoiding a plane reconstruction of the articular surface.
Group 4 had only 1 patient and therefore was not included in our statistical analysis.
Our study indicates that patients with initially well-integrated grafts, well-healed osteotomies, and good joint function could maintain good results over the mean follow-up of 4 years. The best prognosis was for patients with osteochondral lesions accessible through an anterior approach without additional osteotomy.
Our results are promising and confirm the outcome of long-term studies such as that of Hangody et al,15 with 10 years of good experience with osteochondral grafting in osteochondral talar defects.
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FOOTNOTES |
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No potential conflict of interest declared.
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REFERENCES |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
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