Novel Rim Plating Technique for Treatment of the Inferior Pole Fracture of the Patella

To aim of the present paper was to introduce a novel fixation technique for the treatment of inferior pole fracture of the patella. We performed a prospective observational study of consecutive cases of inferior pole fracture of the patella that were treated at our institution between January 2018 and June 2019. The patients include three men and one woman, with an average age of 47 years (range: 42-59 years). All patients were treated with the novel rim plating fixation technique for preserving the inferior pole of the patella. During the surgery, a 2.4 mm straight locking compression plate was contoured to adapt to the arc of the lower half of the patella as the rim plate. After reduction of the fracture, the rim plate was fixed to the proximal fragment of the patella through multiple locking screws, against the continuous pull of the patellar tendon. The rim plate encircles and constricts the inferior pole fragments, functioning as a compression and blocking construct. If necessary, an additional anterior tension band or mini locking plate can be used to further prevent anterior displacement of the inferior pole fragments. Under this rigid fixation, motion of the knee and full weight-bearing were encouraged postoperatively. The patients were followed up monthly until 12 months after surgery. The time to achieve 90°pain-free, full range of motion of the knee, and fracture healing, were recorded. Related complications were monitored, including infection, loss of reduction, fixation failure, anterior knee pain, and soft-tissue irritation. The modified Cincinnati knee rating system was used for knee function assessment. The average operative time was 58.8 min (range: 52-63 min). The average blood loss was 59.8 mL (range: 45-71 mL). For all patients, pain-free 90° range of motion was restored in 2-4 weeks, and the full range of motion was restored in 8-11 weeks. All patients achieved bone union in 6-9 weeks with no displacement of the fragments or breakage of the implant. No patient complained of anterior knee pain or soft-tissue irritation. The modified Cincinnati score at 12-month follow up demonstrated excellent outcomes in all four patients. The rim plating technique may be a feasible option for the treatment of the inferior pole fracture of the patella.