[Treatment of Displaced Patellar Fractures with Multiple Circular Cerclage]

PURPOSE OF THE STUDY The study aims to conduct a mid-term evaluation of results of the treatment of patellar fractures with multiple circular cerclage. MATERIAL AND METHODS The retrospective clinical study with its own group of patients who underwent surgery in our centre in the period from 2008 to 2014. The study included a total of 29 patients with displaced patellar fractures treated with multiple circular cerclage. The available radiographic documentation was assessed and the quality of perioperative reposition, fracture healing, loss of reposition and potential failure of osteosynthesis material was considered. During the clinical examination, the range of motion (ROM) of the operated knee was measured. The current pain was evaluated on the Visual Analogue Scale for Pain (VAS). For evaluation of functional outcomes, the KOOS and LEFS scoring systems were used. RESULTS A total of 27 fractures (93.1%) healed after a mean period of 10.3 weeks after the primary surgery. In 23 cases two circular loops and in six cases 3 loops were used. The mean follow-up period was 66.6 months (range 22-100). The mean duration of the surgery was 59.6 minutes with the mean length of the incision of 11.8 cm (range 9-15). The quality of reposition was evaluated as exact in 23 patients, as adequate in six patients. The mean extension and flexion was 0.2° and 135°, respectively. The individual mean KOOS scores were the following: pain 75.0, symptom 74.5, knee function in daily living 76.7, knee function in sports and recreational activities 48.1, quality of life 57.8. The mean LEFS score was 68.7. The mean VAS score was 2.4. Extraction of osteosynthesis material was done in a total of seventeen cases (58.6%) at a mean of 10 months after osteosynthesis (range 5-14). In altogether five cases (17.2%) the loss of reposition occurred. In two patients pseudoarthrosis developed. Osteosynthesis material failure was reported in two cases (6.9%). DISCUSSION In our study population, by using the technique of multiple circular cerclage 27 fractures (93.1%) healed. In two cases the fractures failed to heal and pseudoarthrosis developed. In one case it was due to non-adherence to the postoperative regimen by the patient. According to the literature, 15-30% of patients suffer from functional limitations. In our study population the mean values of extension and flexion were 0.2° and 135°, respectively. Compared to the group of 17 patellar fractures managed with the modified Pyrford technique where the mean extension and flexion was 0.5° and 131.1°, respectively. According to the data referred to in literature, in up to 80 % cases post-operative pain of anterior knee is reported. In our population the current pain was assessed on the VAS and the mean value of 2.4 was ascertained in comparison to the set of different ORIF surgical procedures and a partial patellectomy, when the final mean VAS score was 2.8. In our population the values of LEFS and KOOS scores are comparable to the values of populations where different surgical techniques were assessed. The post-operative loss of reposition in up to 20% cases is reported by the literature, compared to our population, where it was recorded in a total of 5 cases (17.2%). CONCLUSIONS Multiple circular cerclage is a simple and inexpensive surgical method for treating displaced patellar fractures. It can be used for majority of types of fracture, including comminuted fractures, in which, however, there is a slightly higher risk of loss of reposition. The functional outcomes and the number of complications are comparable to other surgical techniques used. Key words: displaced patellar fracture, multiple circular cerclage, functional outcomes.