Watch out your pins! Periprosthetic femoral fracture at tracking pin site early after robotic-assisted knee arthroplasty treated with dual nail-plate fixation

摘要

Robotic-assisted orthopedic surgeries are gaining popularity due to several factors such as its potential for enhanced precision and alignment in prosthetic implant placement, as well as its better pain control and reduction in hospital stay time. However, complications such as pin-related periprosthetic fractures, though rare, highlight the importance of technical precision during pin placement and adequate postoperative monitoring. We present the case of a 76-year-old obese female patient who presented to the Emergency Department with severe pain and deformity around the knee two months after robotic-assisted total knee arthroplasty following a fall from standing height. Radiographs revealed a displaced femoral periprosthetic fracture at tracking pin sites without associated implant instability. Surgical management involved combined nail-plate fixation, which promoted both early weight-bearing and functional recovery. At one year postoperatively, the patient achieved satisfactory fracture healing and functional outcomes, with a Knee Society Score of 92 and an EuroQol-5D index value of 0.78. Combined nail-plate osteosynthesis, though more invasive compared to other fixation methods, could be an effective strategy for managing distal femoral fractures following robotic-assisted arthroplasty, especially in obese and elderly patients, due to its biomechanical advantages, supporting early mobilization and weight-bearing with reliable fracture healing. • We present a rare case of periprosthetic femoral fracture through pin sites after robotic total knee arthroplasty. • Combined nail-plate fixation enables early weight-bearing and functional recovery, especially in the elderly. • Obesity and femoral pin placement are relevant risk factors for pin related complications in robotic-assisted knee arthroplasty. • More distal intra-incisional pin placement is favored.