[Short-term effectiveness of INBONE total ankle prosthesis arthroplasty in the treatment of moderate to severe varus-type ankle arthritis].

OBJECTIVE

To investigate the short-term effectiveness of INBONE Ⅱ total ankle prosthesis arthroplasty in the treatment of moderate to severe varus-type ankle arthritis.

METHODS

The clinical and radiographic data of patients with moderate to severe varus-type ankle arthritis, who were admitted between May 2017 and November 2021 and treated with total ankle arthroplasty (TAA) using INBONE Ⅱ prosthesis, was retrospectively analyzed. A total of 58 patients (58 ankles) met the selection criteria and were included in the study. Among them, there were 24 males and 34 females, with an average age of 62.6 years (range, 41-85 years). According to the preoperative tibiotalar angle (TTA), the patients were divided into a moderate varus group (group A, TTA 5°-15°, =34) and a severe varus group (group B, TTA>15°, =24). There was no significant difference in gender, side, etiology, preoperative American Orthopaedic Foot and Ankle Society (AOFAS) score, ankle dorsiflexion, plantarflexion, and total range of motion, and tibial lateral surface angle (TLS) between the two groups ( >0.05). Yet the patients in group A were younger than group B, the degrees of oesteoarthritis (Takakura stage) and ankle pain [visual analogue scale (VAS) score] were milder, and the TTA, talar tilt angle (TT), hindfoot alignment angle (HAA) were smaller while the tibial articular surface angle (TAS) was larger, showing significant differences ( <0.05). The pre- and post-operative VAS score, AOFAS score, the occurrence of early and late complications, the radiographic parameters of the ankle (TTA, TAS, TT, HAA, TLS), ankle dorsiflexion, plantarflexion, and total range of motion were recorded and compared.

RESULTS

All patients were followed up 19-72 months, with an average of 38.9 months. Compared with the preoperative data, the VAS score of all patients significantly decreased ( <0.05); the AOFAS score, ankle dorsiflexion range of motion, and total range of motion significantly increased ( <0.05); and the TTA, TAS, TT, HAA, and TLS significantly improved at last follow-up ( <0.05); but there was no significant difference in plantarflexion range of motion ( >0.05). Early complications occurred in 13 patients, and only 1 patient underwent revision surgery due to a larger size of the talar component. At last follow-up, there was no significant difference in the difference of clinical parameters before and after operation between the two groups ( >0.05); there was a significant difference in the difference of other radiographic parameters ( <0.05) except TLS. No significant difference in the incidence of complications between the two groups was found ( >0.05).

CONCLUSION

TAA using the INBONE Ⅱtotal ankle prosthesis is an effective treatment for moderate or severe varus-type ankle arthritis, and good clinical and radiographic results can be obtained. Correcting bony deformities and balancing soft tissue are the keys to successful surgery.