[Our experience with AES total ankle replacement].

PURPOSE OF THE STUDY

The method of choice for the treatment of severe ankle arthritis is either arthrodesis or joint arthroplasty. Each has its advantages and disadvantages. Arthrodesis is the definitive therapy for severe ankle destruction and instability. Joint arthroplasty has an advantage in maintaining ankle mobility. However, its range of indications and its reliability and durability are more limited. The aim of this study is to present our experience with the AES prosthesis and draw attention to some drawbacks of this surgical treatment.

MATERIAL

From September 2003 till June 2008, 51 AES ankle replacements were carried out in 51 patients (33 women and 18 men). Their average age at the time of surgery was 53.8 years. The youngest patient was 23 and the oldest was 88 years old. The indication for surgery was rheumatoid arthritis in 10, primary arthritis in six and post-traumatic ankle arthritis in 35 patients.

METHODS

The patients were evaluated in 2008. The follow-up ranged from 4 months to 5 years. The patients were examined for ankle joint mobility and pain. Radiographs were assessed for potential signs of component loosening.

RESULTS

The results presented here are short-term ones. The pre-operative AOFAS score of 33.7 increased to 82.3 points post-operatively. The range of motion was on average 20 degrees of plantar flexion and 5 to 10 degrees of dorsiflexion. Thirty- five patients (68.7 %) were free from pain, 11 (21.5 %) experienced slight pain while walking, and five (9.8 %) patients reported more intensive pain in the joint treated. Intra-operative complications included a fracture of the medial malleolus in two (3.9 %) patients subsequently treated with screw osteosynthesis. Post-operatively, seven (13.7 %) patients experienced slow healing of the operative wound. One patient had dislocation of the polyethylene liner at 3 months after surgery. Revision surgery was carried out in seven (13.7 %) patients. Two patients suffering from increasing pain around medial malleolus underwent revision and removal of ossifications. One patient developed necrosis of the talus at 1 year after surgery. She underwent extraction of the prosthesis and ankle arthrodesis with a retrograde locking nail inserted through the heel. A large bony effect arising due to extraction of the necrotic talus was repaired using bone graft. Three (5.8 %) patients developed post-operative instability of the ankle that required revision surgery. The radiographs of another three (5.8 %) patients showed bone cysts and signs of tibial component loosening. Of these, one patient underwent surgical revision with replacement of the polyethylene liner. Cavities were freed from granuloma induced by polyethylene wear debris, and filled with bone graft from the iliac crest.

DISCUSSION

Total ankle replacement is a complicated surgical procedure that may results in various technical difficulties and complications. These are inversely proportional to the surgeon's experience, as also shown by literature data.

CONCLUSIONS

The longevity of a total ankle replacement depends, much more than in other joint replacements, on an accurate implantation technique and correct indication.