(Kiosk 2) Recurrent Dislocations Following Total Knee Arthroplasty Secondary to Quadriceps Tendon Rupture: A Case Report

Case Diagnosis: Total knee arthroplasty dislocation secondary to quadriceps tendon rupture.

Case Description or Program Description: An 88-year-old female who underwent an elective left total knee arthroplasty (TKA) at an outside facility presented with generalized weakness and post-operative pain complicated by mechanical falls at home. As a result, she was admitted to our acute inpatient rehabilitation facility due to physical deconditioning post-operatively. Initial functional status included maximal assistance for transfers, contact guard to ambulating 3 meters with a rolling walker (RW), and moderate assistance with certain activities of daily living. Rescue alert was called on the day of admission due to intractable pain with a left knee deformity appreciated on exam. Imaging revealed a TKA dislocation. Upon further questioning, she reports similar incidents at home which resolved with self-reduction. Patient subsequently required reduction with further investigation and close communication with her surgeon at the outside facility.

Setting: Acute rehabilitation hospital

Assessment/Results: Patient was advised to remain weight bearing as tolerated (WBAT) with utilization of a knee immobilizer for 3 weeks at all times until follow up. Magnetic resonance imaging (MRI) of the left knee revealed a quadriceps tendon rupture requiring left quadriceps tendon repair. Post-procedure patient’s functional status significantly improved, with progression to modified independence for transfers and ambulating 100 meters using RW without further episodes of dislocation.

Discussion (relevance): Knee dislocations are considered rare and consist of 0.02-0.2% of orthopedic cases in the general population. Those in the general population who have required a TKA will have a risk of knee dislocation between 0.15–0.5%.

Conclusions: This case report highlights the rare scenario of a TKA dislocation secondary to a quadriceps tendon rupture in the setting of a multidisciplinary team approach within a tertiary care center. Although rare, clinicians should be aware of the potential risk of a TKA dislocation which may warrant further investigation with the potential to improve overall care.