The clinical outcome of the reduction of the patellar inferior pole fracture with wire cerclage through a generated bone hole, in combination with patellar concentrator: a retrospective comparative study.

Objective: The patellar inferior pole fracture is typically comminuted. Hence, achieving firm fixation and early activity is highly challenging. In this article, we employed the method of wire cerclage through a generated bone hole to reduce the fracture. Our objective was to compare the clinical efficacy of patellar concentrator alone with a combination of cerclage and patellar concentrator in the treatment of patellar inferior pole fracture.

Methods: We conducted a retrospective review of patients with patellar inferior pole fractures, who underwent patellar concentrator fixation only (the control group) or cerclage combined with patellar concentrator fixation (the experimental group), performed by a single surgeon, between July 2015 and October 2019. Our analysis included surgical indexes like7 aspects (fracture gap after operation, operation time, intra-operative blood loss, intra-operative number of C-arm fluoroscopies conducted, Insall-Salvati ratio calculated immediately after operation, initial range of motion on the 7th day after operation, and fracture healing time), as well as the Bostman score and complications recorded on 1-, 3-, 6-, and 12-month follow up post operation.

Results: A total of 94 patients with patellar inferior pole fracture and a minimum 1-year follow up were recruited. Following operation, the control group had 33 (71.74%) patients with a fracture gap of 0-2 mm and 13 (28.26%) patients with a fracture gap greater than 2 mm (P = 0.002). Conversely, the experimental group had 46 (95.83%) patients with a fracture gap of 0-2 mm and 2 (4.17%) patients with a fracture gap greater than 2 mm (P = 0.002). Compared to the control group, the experimental group did not experience enhanced operation time or intra-operative blood loss (P = 0.811, P = 0.823). The Insall-Salvati ratio and initial range of motion in the experimental group were larger than the control group (P = 0.037, P = 0.000). Alternately, the number of intra-operative C-arm fluoroscopies conducted and fracture healing time of the experimental group were considerably less than the control group (P = 0.003, P = 0.000). Moreover, at 1-, 3-, 6-, and 12-month follow ups after operation, the Bostman scores of the experimental group were remarkably higher than the control group (P < 0.05). At 12 months post operation, 23 cases (50%) were classified as excellent, 22 cases (47.83%) were good, and 1 case (2.17%) was poor in the control group (P = 0.005). In the meantime, in the experimental group, 38 cases (79.17%) were deemed as excellent and 10 cases (20.83%) were good (P = 0.005). Lastly, complications were detected in 3 cases (6.52%; 1 case of internal fixation loss, 2 cases of hematoma) within the control group, and in 1 case(2.08%; marginal wound necrosis) within the experimental group. There was no wound infection, implant discomfort, or broken fixation in either group.

Conclusion: Managing the patellar inferior pole fracture with wire cerclage through a generated bone hole is both simple and effective. Moreover, an additional step of patellar concentrator fixation facilitates early functional exercise, with satisfactory clinical outcome.