Post-traumatic Osteoarthritis: The Worst Associated Injuries and Differences in Patients' Profile When Compared With Primary Osteoarthritis

Background: Between 10-12% of all osteoarthritis cases are classified as post-traumatic. Patients with post-traumatic osteoarthritis (PTOA) have a higher risk for complications after total joint arthroplasty than patients with primary OA; however, the possible causes remain unknown. A profile of patients with PTOA, more disabling injuries and comorbidities compared to patients with primary OA might help to elucidate. This work aims 1) to identify the most common past injuries associated with the most painful and disabling PTOA cases in a group of non-athlete patients and 2) compare the comorbidities and characteristics between PTOA and primary OA cases. Methods: . Retrospective hospital-based cohort study with 1290 participants with joint complaints or who received arthroplasty. Medical records included demographic information, diagnosis, medication, smoking, alcohol history and comorbidities. Information from the orthopaedic consult included the type and date of injury (for PTOA), pain score by the numerical rating scale (NRS) and walking disability. Results: . There were 641 cases with primary OA (65% females) and 104 with PTOA (61% males). Patients with PTOA were 7.5 years younger (P<0.001), reported more alcohol consumption (P=0.01) and had higher odds of osteoporotic fractures and bipolar disorder or schizophrenia than patients with primary OA (OR= 2.0, CI=1.06-3.78 and OR=2.90, CI=-0.91-9.18, respectively). Knee fractures were most common in males and hip fractures in females (31% and 37.5%, respectively, P<0.005). The PTOA-associated injuries with the highest pain and disability scores were meniscal injuries and hip fractures (NRS=8.3/10, (P-ANOVA=0.04 and P=0.10). There were more diabetes, hypertension, and hypothyroidism cases in Primary-OA than in PTOA (all P<0.05). Conclusions: . PTOA represented 12.4% of all joint diseases in the orthopaedic consult. Past meniscal injuries and hip fractures were the most relevant PTOA associated injuries regarding pain and walking disability. Patients with PTOA have a different profile than patients with primary OA, which would increase their chances of injuries and complications after arthroplasty.