[Use of a silicone metatarsophalangeal joint endoprosthesis in hallux rigidus over a 15-year period].

PURPOSE OF THE STUDY

The aim of this retrospective study was to evaluate the results of a Swanson type, two stem, flexible silicone prosthesis used for first metatarsophalangeal joint replacement in hallux rigidus.

MATERIAL AND METHODS

Between June 1987 and December 2001, we implanted this prosthesis in 145 first toes of 128 patients. This group comprised 83 women (96 replacements) and 45 men (49 replacements); the average age of the group was 49.5 (range, 17 to 82) years. Check-ups carried out in 2002 included clinical and X-ray examination and a questionnaire. Eighty-nine patients presented themselves (63 women and 26 men) and eight patients responded to the questionnaire only. A total of 97 patients (with 108 replacements) were checked up at an average follow-up of 4.75 years (range, 7 months to 15 years). In the questionnaire, we sought information on the patient's satisfaction with the arthroplasty and pain in the joint at rest and when walking in shoes or barefooted. On clinical examination, we assessed the range of motion in the first metatarsophalangeal joint and covering skin status. In X-ray films, we measured the toe axis, replacement status and position, and recorded the presence of bone proliferation.

RESULTS

Of the 97 patients, 38 (43 replacements) were free from any pain; of the remaining 59 patients (65 replacements), 22 experienced pain of varying intensity at rest, 56 (60 replacements) had pain when walking in shoes and 44 (46 replacements) experienced pain when walking barefooted. Satisfaction with the surgical outcome was reported by 85 patients (with 94 operations), which is nearly 79%. Clinical examination showed that, post-operatively, flexion and extension were on average 11 degrees (range, 0 to 30 degrees) and 19 degrees (5 to 50 degrees), respectively. Post-operative infection was recorded in two cases and a pressure sore in the scar in six cases. Only one case required repeat surgery. X-ray examination revealed hallux valgus in 23 cases, failed replacement in six, and osteolytic areas in the vicinities of the distal and the proximal stem were found in 14 and 3 cases, respectively. Calcifications around the implant were recorded in 15 cases and osteophytes were present on the lateral sides of the proximal big toe phalanx and the resected head of the first metatarsal in 65 cases.

DISCUSSION

Several methods have been available for treatment of hallux rigidus. Resection arthroplasty is used most frequently, with interposition arthroplasty second in rank. The osteotomy of either the first metatarsal or the proximal phalanx is preferred in younger patients. Cheilectomy, i.e., removal of dorsal osteophytes involving excision of about 25% of the dorsal part of the head of the first metatarsal, is also a common method, as well as its combination with different types of osteotomy. Total replacement of the first metatarsophalangeal joint is less frequent because neither metal nor hemiphalangeal implants had good outcomes. Flexible silicone two-stem prostheses have been appreciated by the patients but clinical results have been inconsistent; because of frequent failure they have not often been used. The subjective evaluation by our patients was in agreement with assessments reported by other authors; however, our results of clinical examination determining the range of motion were better. Although the average range of motion was not very high (30 degrees), the proportion of our patients in whom the minimal motion was less than 15 degrees was only 11% and this value was markedly lower than reported by other authors. Also our radiographs showed failed implants less frequently than reported in the literature.

CONCLUSIONS

Based on favorable subjective assessments by the patients and a low number of failed implants, this technique can be regarded as an appropriate therapy for middle-aged patients with a diagnosis of hallux rigidus, even though it may not permit a large range of motion in the joint affected.