Sagittal accuracy and functional impact of tibial slope in imageless robotic-assisted Total Knee Arthroplasty.

PURPOSE

Study of the sagittal accuracy of the 'Robotic Surgical Assistant' (ROSA), compared to conventional surgery, regarding the application of the tibial slope (TS). Study of the impact of TS on the range of motion (ROM) and patient-reported outcome measures (PROMS).

METHODS

Inclusion of patients who underwent primary Total Knee Arthroplasty (TKA) between 1/1/2021 and 15/4/2024. Divided into robotic-assisted TKA (RA-TKA) and manual TKA (M-TKA). Measurement of pre- and post-operative TS, using the posterior tibial cortex, on profile knee X-rays. 3° TS applied arbitrarily for both groups. ROM was measured pre-operatively and at three, six and 12 months post-operatively. Patient satisfaction assessed via Knee Injury and Osteoarthritis Outcome Score (KOOS) and Oxford Knee Score (OKS).

RESULTS

266 patients were included in the study. The M-TKA (110) had a post-operative TS of 3.11° (± 2.12°). 81.21% were within 2° of the target and 92.87% within 3°. The RA-TKA (82) had a post-operative TS of -0.11° ± (1.93°). 36.83% were within 2° of the target and 56.63% within 3°. RA-TKA had a KOOS of 64.43 ± 12.87 and OKS of 33.05 ± 6.01. M-TKA had a KOOS of 64.18 ± 13.11 and OKS of 32.31 ± 5.97. Maximum flexion at 12 months was 118.74° ± 8.19° for M-TKA and 121.88° ± 7.43° for RA-TKA (p = 0.002).

CONCLUSION

The application of TS using ROSA was less precise than the conventional method in achieving post-operative TS values as measured on X-rays. However, there were no clinical differences in ROM or PROMS.