Computer-Assisted Total Knee Arthroplasty vs. Conventional Total Knee Arthroplasty: Post-Operative Ankle Radiographic Findings and Ankle Clinical Assessment.

BACKGROUND

A number of previous studies have shown that conventional total knee arthroplasty (TKA) can affect talar tilt (TT) in the ankle of the operated leg. We aimed to prevent this problem by utilizing computer-assisted Total Knee Arthroplasty (CAS-TKA).

OBJECTIVE

To compare pre- and post-operative talar tilt and ankle clinical assessment after computer-assisted total knee arthroplasty (CAS-TKA) and conventional total knee arthroplasty (TKA) in the 56 knees of 28 patients who underwent bilateral TKA.

MATERIAL AND METHOD

We studied the 56 knees of 28 patients who underwent computer-assisted total knee arthroplasty (CAS-TKA) in one knee and conventional total knee arthroplasty (TKA) in the other A combination of the Gap Balancing and Measured Resection techniques was used, and the operations were performed by a single surgeon. At follow-up 12 months post-operatively, we examined ankle radiographic findings for tibio-talar angle (TTA), tibial articular surface angle (TAS), and talar tilt (TT) which was taken as the difference between TAS and TTA. Ankle clinical assessment was performed using the foot functional index (FF) in both groups pre- and post-operatively. The study also compared the results of computer-assisted total knee arthroplasty with those of conventional total knee arthroplasty pre- and post-operatively.

RESULTS

We studied the 56 knees of 28 patients whose mean age was 67.79 years and who underwent bilateral total knee arthroplasty. Comparison of pre-operative and postoperative TT in the Conventional group showed a significant difference (p = 0.016), while there was no significant difference in the CAS group (p = 0.657). Ankle clinical assessment using foot functional index (FFI) revealed that there was no significant difference in the pre-operative FFI in the Conventional group = 1.85 (0.81, 6.88) and that of the CAS group = 1.91 (0.24, 66.5) (p = 0.577). The post-operative FFI in the Conventional group was 1.68 (0.24, 7.0) and in the CAS group it was 1.65 (0.24, 6.76), and these results were statistically significant (p = 0.047). In the Conventional group, the postoperative FFI was not significantly different from pre-operative FFI (p = 0.269), but in the CAS group there was a significant difference (p = 0.047).

CONCLUSION

This study showed that conventional total knee arthroplasty affected postoperative talar tilt while computer-assisted total knee arthroplasty had a lesser effect and did not significantly change the axis of rotation of the ankle joint. More research needs to be carried out on larger numbers of patients with longer follow-up periods.