Working Diagnosis:
Bilateral Patellar Tendon Rupture

Treatment:
The patient was provided with bilateral knee immobilizers, crutches and was able to ambulate out of the emergency department. He underwent operative bilateral patellar tendon repairs two days post injury.

Outcome:
He was discharged home on post-operative day 1 with instructions to be weight bearing as tolerated in the bilateral lower extremities with hinged knee braces locked in extension at all times. At 8 weeks post operatively, the patient progressed to ambulating with knee braces, no longer locked in extension, and began physical therapy for range of motion. At 14 weeks post operatively, the patient progressed to ambulating without knee braces. He has no difficulties with activities of daily living though he is hesitant to go down stairs. Physical therapy was advanced to include quad strengthening at this point. At 6 months post-operatively, he is able to do all ADLs without difficulty or bracing. He has not returned to running and jumping. Plan to continue home physical therapy and follow up at 1 year post-op.

Author's Comments:
Patellar tendon rupture has been reported to be misdiagnosed on initial presentation up to 28% of the time. Though a rare diagnosis, it is important for clinicians to make the diagnosis on initial evaluation as delays in care can lead to complications. Simultaneous bilateral patellar tendon rupture is exceedingly rare with approximately 60 case reports in the medical literature. Most of these cases are associated with systemic diseases such as systemic lupus erythematosus, diabetes mellitus, rheumatoid arthritis, chronic kidney disease, hypothyroidism or the use of medications such as corticosteroids, fluoroquinolones or statins. Of the cases with no known systemic illness or medications of cause, the rupture occurs at the inferior pole of the patella with a few occurring in the midsubstance portion of the tendon. This is consistent with our patient experiencing disruptions at the inferior poles of the patella bilaterally.

Editor's Comments:
Patellar tendon rupture can occur following a sudden quadriceps contraction while the knee is in a flexed position. Common mechanisms in athletes include landing from a jump or making a sudden change in direction. Rupture can also occur when falling backwards while the foot or feet are fixed to the ground (thereby exerting a large eccentric force). A sudden pop, tearing sensation or pain can be described by the individual when rupture occurs. They may also have difficulty ambulating after patellar tendon rupture.
On exam, there can be localized tenderness, a palpable gap between the tibial tubercle and patella, ecchymosis, hemarthrosis, and elevation of the patella. One significant exam finding often helping distinguish a complete tear from a partial tear is the ability to perform an active straight leg raise or maintain extension of a passively extended knee.
Imaging can include x-ray, ultrasound, and MRI depending on the patient and presentation. Lateral x-ray will be most useful and will show patella alta (inferior patellar border will lie above Blumensaat's line). Musculoskeletal ultrasound is most useful in demonstrating partial versus complete tendon tears however it is operator dependent. MRI is typically ordered only when the diagnosis remains unclear despite history, exam, and other imaging.
For complete tears, consider secondary causes such as renal disease, metabolic causes such as lupus, hyperthyroidism, or hyperparathyroidism, and medications such as quinolones or steroids. Outcomes are best for complete tears when surgery is performed within one week of the injury. The patient should be placed in an extension splint until surgery is performed. Subsequent physical therapy will be necessary to regain range of motion and quadriceps strength.

Return To The Case Studies List.