Good long-term outcomes with Buechel-Pappas total ankle replacement

Researchers found several complications during the nine-year follow-up and patients must be carefully selected.

The only long-term outcome results for the Buechel-Pappas total ankle replacement system currently originate from a single surgeon’s experience.

However, new research from the Royal Cornwall Hospital in Truro now shows good long-term results with this prosthesis. Investigators presented their early results to the British Orthopaedic Foot Surgical Society in 1997 and have now followed 19 patients (22 prostheses) for a mean of nine years. They presented their new data at the British Orthopaedic Association (BOA) 2005 Annual Congress.

The study included 12 women and seven men with a mean age of 64 years. Eleven patients had rheumatoid arthritis (12 ankles) and eight had osteoarthritis (10 ankles). The senior author of the study, Stephen W. Parsons, FRCS, operated on all patients.

No patients were lost to follow-up. At the time of review, the researchers noted two prosthesis failures — one for infection and one for avascular necrosis. One prosthesis was also removed when a patient underwent a below-knee amputation for chronic venous ulceration. Four patients (six ankles) had died from non-related events. Of the remaining 13 ankles, only one patient reported impingement pain and another noted intermittent pain. All continued to function well, however.

Total ankle scores improved from 34 points at preop to 81.6 points at long-term follow-up using an assessment derived from the New Jersey LCS Ankle score. Pain scores improved from 8.2 to 34.8 points during this period, with a score of 40 points indicating no pain. Function scores also improved, from 6.5 points at preop to 32.8 points, and range of motion scores improved from 7.1 points preoperatively to 10 points at long-term follow-up.

“We conclude that in a selected group, the Buechel-Pappas total ankle replacement (Endo Tec, US..; Wright Cremascoli Orthopaedics, Europe) offers good pain relief, improved function and preserves range of motion. We can now say that these benefits are maintained in the long-term,” researcher Nicholas J. Talbot, FRCS, said during his presentation at the BOA Congress.

Lucent lines, complications

Radiographic evaluation showed posterior tilt greater than 10° in two talar components early in the series, Talbot said. “Lucent lines developed around eight prostheses and, in three, lucent lines were around both components. However, the development of lucent lines did not correlate adversely with clinical outcome and no component was radiologically loose,” he said. Investigators found significant talar sinking in an avascular necrosis patient, “but there was no other significant component movement,” Talbot added.

The researchers also discovered several complications. One patient developed an infection that led to wound breakdown, two patients experienced a medial malleolar fracture and one patient suffered a medial cortex fracture. “We’ve had three iatrogenic fractures and, in patients who we feel are at high risk for developing a malleolar fracture, we advocate prophylactic fixation with a cannulated screw,” Talbot said.

“We also had a transient neuropraxia to superficial peroneal nerve and an intraoperative iatrogenic transaction of the tibial nerve, which we recognized and repaired with good function and recovery,” he added.

Despite these complications, the researchers hold that the study adds evidence to the effectiveness of the device. “Our results suggest that the Buechel-Pappas total ankle replacement offers good clinical and radiological results to patients with often disabling ankle arthritis,” they wrote in their abstract.

However, the researchers emphasized that the prosthesis is primarily indicated for those with polyarthropathy and less than 10° of coronal plane ankle deformity. Ankle fusion remains the gold standard in the young, active patient with single joint involvement and those with neurological or vascular compromise, Talbot said.

For more information:
Talbot NJ, Trimble KT, Sharpe IT, et al. Long-term outcome of the Buechel-Pappas total ankle replacement. Presented at the British Orthopaedic Association Annual Congress. Sept. 20-23, 2005. Birmingham, England.