Long-Lasting Hyperalgesia Is Common in Patients Following Patella Fractures.

Background: The objective was to investigate the long-term development of pain and hyperalgesia after patella fractures. The secondary objective was to report the association between tibiofemoral and patellofemoral osteoarthritis, pain, and hyperalgesia. Methods: The study used a cohort design. Patients who were treated for patella fractures between January 2006 and December 2009 were identified. Patients age 20 to 78 years were included. The main outcome was the pain pressure threshold (PPT). Moreover, visual analog scale (VAS) for pain, radiological outcomes of patellofemoral and tibiofemoral osteoarthritis, and the pain subscale of the WOMAC and EQ-5D questionnaires were used. Results: Forty-nine patients were included, with a mean age of 53.9 years and a mean follow-up time of 8.5 years. The injured knee region showed significantly decreased PPT levels (P < 0.046), but decreases in PPT were not found for the forearm region (P = 0.24). The VAS score for the worst pain during the last 24 hours was reported, with a mean of 2.9 ± 2.4 cm. The EQ-5D-5L-pain scale was reported, with a mean score of 2.4 (95% confidence interval [CI] = 2.0-2.7). The WOMAC Pain score was reported, with a mean score of 3.9 (95% CI = 2.8-4.9). Moderate correlations were found between the VAS scores and PPT levels (R = 0.428, P = 0.002). Weak correlations were found between VAS scores and PPT levels for site 7 (forearm; R = 0.313, P = 0.03). Conclusions: The present study suggests that long-lasting local hyperalgesia following a patella fracture is common. No side-to-side difference at the forearms were observed, indicating that the observed local hyperalgesia was not part of a generalized sensitization.

Incidence and Epidemiology of Patellar Fractures.

The literature lacks large-scale, up-to-date, population-based epidemiology studies on the incidence of patellar fractures based on complete populations. The purpose of this study was to provide up-to-date information concerning the incidence of patellar fractures in a large and complete population spanning a decade and to report on the distribution of fracture classification, trauma mechanisms, and patient baseline demographics. A retrospective review of clinical and radiological records of 756 patellar fractures treated between 2005 and 2014 was conducted. Mean age at the time of fracture was 54±21 years. Mean age was 46±22 years for males and 61±18 years for females. The sex distribution was 425 (56%) females and 331 (44%) males. The incidence of patellar fractures between 2005 and 2014 was 13.1/100,000/ year with a year-to-year variation between 10.5 and 16.5/100,000/year during the 10-year observation period. The distribution of incidence shows an increase with increasing age. Males have the highest incidence of fracture in the 10-to-19-year age group, approximately 15.4/100,000/year. Females in the 60-to-80-year age group have the highest incidence, approximately 36/100,000/year. AO type 34-C3 was the most common fracture type, representing 25% of all patellar fractures, followed by AO type 34-C1, representing 23%. [Orthopedics. 2016; 39(6):e1154-e1158.].