Comparison of a Novel Tension Band and Patellotibial Tubercle Cerclage in the Treatment of Comminuted Fractures of Inferior Pole of the Patella

OBJECTIVE: To assess the therapeutic effect of a novel tension band using 3.0 mm cannulated screw combined with a titanium cable and specific shims comparatively with patellotibial tubercle cerclage in comminuted fractures of the inferior pole of the patella. METHODS: The retrospective study from March 2012 to July 2017 was conducted in Peking University Third Hospital and comprised 63 patients with comminuted fractures of the inferior pole of the patella: 41 treated with new tension band using 3.0 mm cannulated screw combined with a titanium cable and specific shims (new tension band group) and 22 with patellotibial tubercle cerclage (tubercle cerclage group). Gender, age, AO/OTA fracture type, injury mechanism, inter‐fragmentary gap, and follow‐up time of patients were recorded. Two groups were compared regarding: operation time, blood loss, partial weight‐bearing time, fracture‐healed time, Bostman score and knee mobility at 12‐month follow‐up, and postoperative complications. Continuous and categorical parameters were analyzed by Mann‐Whitney U test and the chi‐squared test, respectively. Fisher's exact test was used for small data subsets. RESULTS: Between the two groups, no statistically significant difference was found in mean age, gender, AO/OTA fracture type, injury mechanism, mean inter‐fragmentary gap, or mean follow‐up time (P > 0.05). The mean operation time of new tension band group was significantly longer than that of tubercle cerclage group (76.4 min vs 64.2 min, P = 0.006), while there was no significant difference in blood loss. After surgery, new tension band group had a significantly earlier mean partial weight‐bearing time (5.2 weeks vs 7.4 weeks, P < 0.001) and fracture‐healed time (9.6 weeks vs 11.6 weeks, P < 0.001). At 12‐month follow‐up, patients of new tension band group had a significantly higher mean Bostman score (28.5 vs 25.8, P < 0.001) and knee mobility (126.7 vs 117.3, P < 0.001). Ten complications related with internal fixation were found in tubercle cerclage group including two cases of loose internal fixation, two cases of cerclage breakage, and six cases of low patella position who undertook secondary operation. No complications were found in new tension band group (0 in 41 vs 10 in 22, P < 0.001). CONCLUSION: Patients with comminuted fractures of the inferior pole of the patella treated with a novel tension band experienced a longer operation time, but earlier partial‐weight‐bearing and fracture‐healed time, better clinical outcomes at 12‐month follow‐up, and less complications. It should be considered an alternative therapy for the treatment of distal pole patellar fractures.