Impact of the femoral pin tracker on periprosthetic fractures in robotic-assisted total knee arthroplasty
摘要
Robotic-assisted total knee arthroplasty (TKA) requires pin trackers fixed to the femur and tibia. The influence of femoral pin tracker placement (intra-incisional or extra-incisional) on fracture risk remains controversial, with limited clinical and biomechanical evidence.
MethodsA retrospective cohort study included 688 patients who underwent robotic-assisted TKA (505 in intra-incisional group, 183 in extra-incisional group). The incidence of femoral periprosthetic fractures was compared between the two groups within three months postoperatively. Finite-element analysis (FEA) simulated femoral biomechanical behaviour under compression, torsion, and bending loads in three models: control, intra-incisional, and extra-incisional groups.
ResultsOne fracture occurred in the extra-incisional group (1/183, 0.55%), whereas none occurred in the intra-incisional group (0/505), the difference was not statistically significant (Fisher's exact test, P = 0.266). In the FEA, ultimate loads and fracture patterns were similar among the control, intra-incisional, and extra-incisional models under all three loading conditions, and no simulated fracture initiated at nail channels.
ConclusionPerioperative femoral fracture involving tracker nail channels was rare in this cohort, and its incidence did not differ significantly between intra-incisional and extra-incisional placement. When a standardized pin-placement protocol is followed, either location appears to have a limited effect on short-term fracture risk.