Background: Patella fractures treated with traditional open approach and tension band fixation are associated with a significant rate of soft tissues complications, including hardware irritation, postoperative adhesions and non-cosmetic scar. An alternative is to utilize cannulated screws and high-strength sutures by the minimally invasive technique.
Methods: This retrospective study comprised 48 patients who had been treated for unilateral closed transverse patellar fracture, type 34C1 according to the AO Foundation and Orthopaedic Trauma Association (AO/OTA) classification, between June 2018 to June 2020. All patients were treated either by closed reduction and internal fixation using cannulated screws combined with high-strength sutures and Nice knots (the CRIF-NK group, n=24), or traditional open reduction and internal fixation using cannulated screws and tension band wiring (the ORIF-TBW group, n=24). The operative time and intraoperative blood loss for each patient were recorded. All the patients were underwent a regularly clinical and radiological follow-up. The clinical evaluation was performed using the Böstman scale and the Visual Analogue Scale (VAS) for pain.
Results: Average follow up was 21.9 months (range, 16-29 months). The mean intraoperative blood loss of the CRIF-NK group (35.21±6.16 mL) was significantly less than that of the ORIF-TBW group (75.42±7.92 mL; P<0.001). The mean VAS scores at 4 and 8 weeks and the mean Böstman scale score at 8 weeks after surgery were significantly better in the CRIF-NK group (3.52±0.42, 1.47±0.40 and 28.13±0.94, respectively) than the ORIF-TBW group (5.16±0.68, 3.14±0.72 and 26.33±1.00, respectively; all P<0.001). No significant differences were observed between the two groups in terms of operative time, Böstman scale score at 1-year follow-up, or fracture healing time. The union rate was 100% (24/24) in both groups. One patient (1/24) in the CRIF-NK group, and all patients (24/24) in the ORIF-TBW group required internal fixation removal.
Conclusions: The percutaneous minimally invasive technique using cannulated screws combined with high-strength sutures and Nice knots exhibited some superiority to traditional open reduction with cannulated screws and tension band wiring for treatment of transverse patellar fractures in terms of efficacy and safety by reducing soft-tissue stimulating complications and promoting functional recovery.
Keywords: Nice knot; Patellar fracture; closed reduction; high-strength suture.