Separate vertical wiring for the fixation of comminuted fractures of the inferior pole of the patella.

Abstract

PURPOSE: Among patients over 50 years of age, separate vertical wiring alone may

be insufficient for fixation of fractures of the inferior pole of the patella.

Therefore, mechanical and clinical studies were performed in patients over the

age of 50 to test the strength of augmentation of separate vertical wiring with

cerclage wire (i.e., combined technique). MATERIALS AND METHODS: Multiple

osteotomies were performed to create four-part fractures in the inferior poles of

eight pairs of cadaveric patellae. One patella from each pair was fixed with the

separate wiring technique, while the other patella was fixed with a combined

technique. The ultimate load to failure and stiffness of the fixation were

subsequently measured. In a clinical study of 21 patients (average age of 64

years), comminuted fractures of the inferior pole of the patellae were treated

using the combined technique. Operative parameters were recorded from which

post-operative outcomes were evaluated. RESULTS: For cadaveric patellae, whose

mean age was 69 years, the mean ultimate loads to failure for the separate

vertical wiring technique and the combined technique were 216.4+/-72.4 N and

324.9+/-50.6 N, respectively (p=0.012). The mean stiffness for the separate

vertical wiring technique and the combined technique was 241.1+/-68.5 N/mm and

340.8+/-45.3 N/mm, respectively (p=0.012). In the clinical study, the mean

clinical score at final follow-up was 28.1 points. CONCLUSION: Augmentation of

separate vertical wiring with cerclage wire provides enough strength for

protected early exercise of the knee joint and uneventful healing.