SLR - February 2013 - Brouyette
References: Taniguchi, Takakura, Sugimoto, Hayashi, Ouchi, Kumai, Tanaka. The use of a Ceramic Taler Body Prosthesis in Patients with Asceptic Necrosis of the Talus. J Bone Joint Surg Br. 2012; 94-B : 1529-33.
Scientific Literature Review
Reviewed by: Nicole M. Brouyette, DPM
Residency Program: St. John Hospital and Medical Center
Podiatric Relevance:
The talus has no muscular or tendinous attachments, and therefore has a relatively poor blood supply when compared to the other articular bones. Interruption of the intraosseous blood supply secondary to fracture of the talar neck or dome can lead to avascular necrosis. Avascular necrosis of the talus from any etiology is a devastating pathology. Although there are a few surgical salvage options available for the treatment of this, the best surgical treatments for talar avascular necrosis is unknown.
Methods:
Using two types of ceramic prostheses, 22 patients with necrosis of the talar dome underwent replacement. Four men and 18 women with a mean age of 65.5 years old were included in the analysis. Necrosis was caused by fracture of the talar neck in two patients and was idiopathic in 20. Diagnosis was confirmed by MRI in all cases.
Two types of prosthesis were made. The first was a first generation prosthesis with a peg placed on the implant to allow fixation to the neck of the surviving talus with bone cement. This was trialed in eight patients. The second was a second-generation prosthesis that was not fixed to the neck of the talus and trialed on 14 patients. The postoperative course included a below-knee, non-weight-bearing cast for the first two weeks. A half weight-bearing cast was applied for the next two weeks and full weight-bearing was allowed at five weeks. Patients were assessed preoperatively and at the time of final examination using the American Orthopaedic Foot and Ankle Society (AOFAS) ankle/hindfoot scoring scale. Radiological results were assessed immediately post-op, and then at six months, one year, two years and three years after surgery. The following parameters were evaluated radiographically: presence of loosening, presence of collapse of talar head, and presence of osteophytes.
Results:
The mean follow-up was 96 months. Using the AOFAS scale, the mean pain score was 15 (zero to 20) pre-op and 32.5 (20-40) at the final follow-up. Mean function improved from 24.8 (18-31) pre-op to 38.8 (25-47) and mean alignment from 6.9 (zero to 10) to 8.9 (five to 10). The total mean score improved from 46.6 (21-60) to 80.0 (50-97) (p<0.001, paired t-test). Radiological evidence of loosening and necrosis of the talar head became evident in all patients one year post-op. Clinical results were excellent in three, good in one, fair in three and poor in one. Aside from two patients, most had no pain or slight pain and resumed normal activity.
The second generation prosthesis mean follow-up was 83 months. Mean pain scores were 20.0 (10-30) pre-op and 31.4 (20-40) at final follow-up. Mean function improved from 24.8 (nine to 37) pre-op to 40 (28-48), and mean alignment from 5.4 (zero to 10) to 9.6 (five to 10). Total mean score improved from 50.4 (29-67) to 81.1 (64-98) (p<0.001). Clinical results were excellent in three, good in five, fair in four and poor in two. Patients with fair and poor results had severe loosening with fractures in the talar neck and head at 19 and 43 months post-op. These went on to total talar implant.
Conclusions:
The principle problems encountered with this prosthesis were loosening and sinkage. Four of eight patients (50 percent) had favorable results with the first generation prosthesis, despite poor radiological features. Two patients with fracture of the talar neck and head underwent revision using total implant. Removing the peg design in the second generation implant to avoid concentration of stress at the site of fixation resulted in eight of 14 patients (57 percent) with favorable results and the mean post-op score was >80, in addition to being radiologically more satisfactory. In review of these complications the authors recommend the use of total talar implant in patients with AVN even if the talar neck and head are preserved.