Persistent Quadriceps Weakness Presenting As Balance Impairment After Bilateral Quadriceps Tendon Repair: A Case Report

BACKGROUND: Balance concerns and gait instability are common referral diagnoses in older adults, but may not capture underlying impairments amenable to rehabilitation. CASE PRESENTATION: A 78-year-old male was referred to physical therapy for balance impairment and recurrent falls two years after bilateral quadriceps tendon repair. Examination revealed severe, persistent deficits in active knee extension and quadriceps strength, without evidence of neurologic or vestibular pathology. OUTCOME AND FOLLOW-UP: Persistent knee extensor weakness following bilateral quadriceps tendon repair was identified as the primary diagnosis. Over 12 weeks of progressive rehabilitation emphasizing quadriceps strengthening, the patient demonstrated clinically meaningful improvements in strength, balance, and patient-reported outcomes, although intermittent knee buckling persisted. DISCUSSION: This case illustrates how anchoring bias may influence clinical reasoning when older adults present with balance concerns, as reliance on referral diagnoses can narrow examination focus and delay identification of modifiable impairments such as muscle weakness.