HSS Ultrasound of the Month Case 82

Clinical History A 62 year old male status post right distal radius open reduction and internal fixation in 2011 presents with the inability to flex his right thumb at the interphalangeal joint after doing heavy housework two weeks prior.

Clinical concern was for flexor tendon attrition.

Ultrasound evaluation of the right wrist was requested.

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Diagnosis: Flexor pollicis longus (FPL) tendon rupture superimposed on moderate to severe FPL tendinosis Treatment Right distal radius hardware removal Right flexor pollicis longus tendon reconstruction with a palmaris longus tendon autograft

Discussion Flexor tendon rupture is a relatively infrequent, yet significant complication following distal radius fracture open reduction and volar plate fixation.

Patients present with worsening pain, crepitus and/or decreased finger active range of motion.

Most flexor tendon ruptures take place approximately 6 months to two years following surgery.

Flexor tendon ruptures resulting from volar plating occur twice as frequently in women and 1/3 of the time present between the ages of 60 and 70; however, this may be related to the increased incidence of distal radius fractures occurring in this population as a result of osteoporosis.

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Discussion - continued Factors contributing to attrition of the flexor tendon include distal plate placement, prominence of the distal edge of the plate, protruding screw heads, insufficient coverage of the distal plate edge by the pronator quadratus, fracture site collapse, tendinopathy (i.e. steroid use) as well as tendon injury.

Treatment of flexor tendon rupture consists of hardware removal and flexor tendon repair.

Possible interventions to prevent flexor tendon injury following distal radius volar plating include proper plate selection and placement, precise surgical technique, repair of the pronator quadratus muscle, and/or early hardware removal.

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