Inferior patellar pole avulsion fractures: osteosynthesis compared with pole resection.

BACKGROUND

The ideal treatment for avulsion fractures of the inferior pole of the patella has not yet been identified. The options include (1) internal fixation of the pole fragment and (2) resection of the avulsed fragment and repair of the patellar ligament to the patella. We are not aware of any previous study in which the results of internal fixation have been compared with those of pole resection. The purpose of the present study was to compare the long-term results of internal fixation (with use of a basket plate) with those of pole resection.

METHODS

We retrospectively studied two groups of patients who had had operative treatment of an avulsion fracture of the inferior patellar pole between 1990 and 1997. Fourteen patients had had internal fixation with a basket plate, and fourteen had had pole resection with patellar ligament repair. Eleven patients who had had internal fixation (Group A) and thirteen patients who had had pole resection (Group B) were followed for an average of 4.6 years. The final evaluation was based on the patellofemoral score, and the patellar height was measured radiographically.

RESULTS

The average patellofemoral score (maximum, 100 points) was 94.1 points in Group A and 81.2 points in Group B. Significant differences between the groups were noted with regard to knee pain, level of activity, and range of motion. Normal patellar height was found in ten of eleven patients in Group A and in three of thirteen patients in Group B. Patella baja was significantly associated with a poor functional outcome.

CONCLUSIONS

In patients who have sustained an avulsion fracture of the inferior patellar pole, the normal height of the patella can be maintained by preserving the patellar pole. In contrast with pole resection, which requires postoperative immobilization, internal fixation with a basket plate allows for immediate mobilization and early weight-bearing. The present study indicates that internal fixation with use of a basket plate can provide better clinical results.