Spontaneous Bilateral Quadriceps Tendon Rupture without Traditional Risk Factors: A Case Report

Case Diagnosis: Spontaneous nontraumatic bilateral quadriceps tendon rupture.

Case Description or Program Description: Patient was a 59 year old male who was in the process of kneeling down when he felt a pop in both knees, and subsequently was found to have bilateral quadricep tendon rupture. He was diagnosed via ultrasound, with bilateral repair 1 day after injury. He had a recent traumatic left full-thickness supraspinatus tear with repair 5 weeks prior, and remained non-weightbearing to this extremity at the time of this injury. He also had bilateral knee arthrocentesis for osteoarthritis 5 days before his injury. Other comorbidities included prediabetes, hyperlipidemia on low-dose rosuvastatin, and hypogonadism on transdermal testosterone. He had evidence of testosterone use with erythrocytosis 5 weeks before the injury, but with testosterone levels on the lower limit of normal on admission to rehab.

Setting: Inpatient Acute Rehabilitation Unit

Assessment/Results: The patient was required to keep his knees locked in extension with Bledsoe braces for 6 weeks while completing physical therapy for his injuries.

Discussion (relevance): Typical risk factors associated with bilateral quadriceps tendon rupture include calcific tendinosis associated with chronic kidney disease, gout, or hyperparathyroidism, vitamin D deficiency, anabolic steroids, uncontrolled diabetes mellitus, and connective tissue or autoimmune disorders. Rare associations include bone spurs associated with knee osteoarthritis, as well as intra-articular steroid injections. Meghani et al. (2023) noted a significant association with testosterone prescription and quadricep tendon injury, but the study did not distinguish between systemic and transdermal testosterone. Other than testosterone use, our patient possessed no major risk factors. Although he took rosuvastatin, his prescription was low-dose, for which there is little supportive literature as a major risk factor for tendon rupture.

Conclusions: This is a case of bilateral quadriceps tendon rupture with recent supraspinatus tendon rupture in a relatively healthy 59 year old man with no known risk factors except for transdermal testosterone use.