Injection Technique for Thigh Splints

Indications and Clinical Considerations

The musculotendinous unit of the distal adductor muscles of the hip joint is susceptible to developing tendinitis and tendinopathy from overuse or trauma from traction injuries at the site of the insertion of these muscles on the femur ( Fig. 130.1 ). Inciting factors may include the vigorous use of exercise equipment for lower extremity strengthening and acute stretching of the musculotendinous units as a result of sports injuries and/or military training. Analogous to shin splints, the pain of thigh splints is localized to the medial thigh and groin and is described as sharp, constant, and severe. Sleep disturbance is often reported. The patient may attempt to splint the inflamed tendons by adopting an adductor lurch type of gait (i.e., shifting the trunk of the body over the affected extremity when walking).

On physical examination, the patient will report pain on palpation of the insertion of the adductor tendons. Active resisted adduction and passive abduction reproduce the pain. Patients with adductor tendinitis will also exhibit a positive Waldman knee squeeze test. This test is performed by having the patient sit on the edge of the examination table. The examiner places a tennis ball between the patient’s knees and asks the patient to gently hold it there with gentle pressure from the knees ( Fig. 130.2A ). The patient is then instructed to quickly squeeze the ball between the knees as hard as possible. Patients with adductor tendinitis will reflexively abduct the affected extremity because of the pain of forced adduction, causing the ball to drop to the floor ( Fig. 130.2B ).

Thigh splints frequently coexist with bursitis of the associated bursae of the hip joint, creating additional pain and functional disability. In addition to the previously mentioned pain, patients with thigh splints often experience a gradual decrease in functional ability with decreasing hip range of motion, making simple everyday tasks such as getting in or out of a car difficult. With continued disuse, muscle wasting may occur and an adhesive capsulitis of the hip may develop.

Plain radiographs are indicated for all patients with hip, groin, and thigh pain. Patients with thigh splints will demonstrate a periosteal reaction, and an avulsion fracture may be seen (see Fig. 130.1 and Fig. 130.3A ). On the basis of the patient’s clinical presentation, additional testing may be indicated, including complete blood cell count, sedimentation rate, and antinuclear antibody testing. Magnetic resonance imaging (MRI) and ultrasound imaging of the hip, groin, and femur are indicated if tendinitis, aseptic necrosis of the hip, tear or avulsion of the adductor muscles, or occult mass is suspected ( Figs. 130.2B and 130.3 ). In patients with thigh splints, MRI will reveal increased signal intensity of the proximal and midshaft of the femur with increased signal on short tau inversion recovery images from the periosteum and endosteal surface ( Fig. 130.4 ). Ultrasound imaging of this area may reveal periosteal edema. Radionuclide scanning may reveal increased uptake at the insertion of the adductor muscles on the femur ( Fig. 130.5 ). A failure to treat distal adductor tendinopathy can result in complete tear of the distal abductor musculotendinous insertional unit with proximal retraction of the adductor muscles ( Fig. 130.6 ).

The injection technique described later serves as both a diagnostic and a therapeutic maneuver.