Athletes who use wheelchairs are particularly susceptible to overuse injuries affecting the upper limb because of repetitive wheelchair propulsion and transfers. The shoulder is the most common site of injury among wheelchair athletes, and the most frequently affected structures include the rotator cuff and biceps tendon. Ultrasound has been shown to have high accuracy in evaluating for rotator cuff and biceps tendon pathology. Adaptive athletes, specifically those with long-term wheelchair use, often present with degenerative changes in these shoulder structures that may or may not be symptomatic. Therefore, the history and physical examination should always be used in conjunction with the imaging results during clinical decision making. This interplay between shoulder symptoms, wheelchair use/history, physical examination, and shoulder abnormalities on ultrasound has been the subject of several studies. ^,,,

Brose and colleagues investigated the presence of ultrasound abnormalities in the shoulder among wheelchair athletes and correlated the ultrasound findings with history and physical examination. The authors found a significant correlation between the duration of spinal cord injury (SCI) and the severity of shoulder pathology, as assessed by ultrasound, with abnormalities in the ultrasound findings corresponding to physical examination for specific shoulder structures. Another study by Collinger and colleagues investigated ultrasound changes in the biceps and supraspinatus tendons in wheelchair athletes following an intense wheelchair propulsion task. Subjects with a higher stroke frequency or resultant force tended to have more hyperechoic and more organized biceps tendon appearance compared with baseline. Subjects with a longer duration of wheelchair use were at increased likelihood to have a more hypoechoic and more diffuse biceps tendon appearance compared with baseline. Further, the authors found that ultrasound measures of the supraspinatus tendon correlated to clinical signs of shoulder pathology, such as pain with specific physical examination tests, similar to the findings by Brose and colleagues. ^,

A study involving elite wheelchair tennis players found a high prevalence of rotator cuff pathology and acromioclavicular joint pathology in the dominant and nondominant shoulders. Ultrasound was used to identify specific shoulder pathologies, including acromioclavicular pathology and full-thickness rotator cuff tears ( Fig. 1 ), in both the dominant and nondominant shoulders of the participants, with acromioclavicular pathology affecting 63.6% of dominant shoulders in elite wheelchair tennis players. There were no correlations between the shoulder pathology and age, training time per day, length of wheelchair use, or length of career as a wheelchair tennis player.

Ultrasound image of a full-thickness supraspinatus tendon tear ( white arrow ) in a wheelchair athlete in long axis view ( A ) and short axis view ( B ).

Blauwet and colleagues studied the relationship between shoulder pain, physical examination, and tissue pathology, as determined by ultrasound, in manual wheelchair users competing in elite sport. They found a high prevalence of shoulder symptoms, positive signs on physical examination, and ultrasound-determined tissue pathology. However, ultrasound-determined tissue pathology did not correlate with symptoms or signs, suggesting some pathology may be asymptomatic. These degenerative changes may be detected through ultrasound but are not always clinically relevant, highlighting the need for careful interpretation of ultrasound findings alongside a thorough history and physical examination.

Soo Hoo and colleagues compared the prevalence of shoulder pain among wheelchair athletes, nonathletic wheelchair users, and nonwheelchair users, using questionnaire, physical examination, and ultrasound evaluation. The authors found that, although wheelchair use is a risk factor for shoulder pain, participation in amateur wheelchair sports may not be associated with increased risk of shoulder pain.

These studies highlight the importance of combined clinical and ultrasound evaluation when assessing shoulder pathology in adaptive athletes. Although the correlation between shoulder pathology on ultrasound, wheelchair use/history, and physical examination is not entirely certain, the application of ultrasound in accurately evaluating shoulder pathology that is commonly seen in wheelchair athletes is well established. Ultrasound also allows for a low cost and convenient way to monitor shoulder pathology, such as progression of a rotator cuff tear, to optimize treatment.

Wheelchair propulsion and transfers also place repetitive stress on the elbows, often resulting in elbow pain. Lateral epicondylosis or tennis elbow is a common cause of elbow pain caused by repetitive gripping or twisting motions of the wrist. The prevalence of lateral epicondylosis has been found to be higher among manual wheelchair users participating in wheelchair sports compared with the able-bodied population. Cyr and colleagues used ultrasound evaluation and physical examination to assess the prevalence of lateral epicondylosis in wheelchair athletes who attended the National Veteran Wheelchair Games. Thickening and hypoechoic appearance of the common extensor tendon on ultrasound, as well as calcifications, tears, or bony irregularity of the lateral epicondyle were seen in wheelchair athletes with lateral epicondylosis ( Fig. 2 ). These ultrasound changes were associated with increased age and increased years using a manual wheelchair.

Ultrasound image of lateral epicondylosis/common extensor tendon tear ( white arrow ) in a wheelchair athlete in long axis view.

Wheelchair athletes have also been found to have a higher prevalence of ulnar neuropathy at the elbow, which is an entrapment neuropathy causing pain and paresthesias into the fourth and fifth fingers and possibly hand weakness. Kakita and colleagues studied wheelchair marathon athletes and ulnar neuropathy at the elbow using questionnaire, physical examination, and ultrasound. The authors found a higher prevalence of ulnar neuropathy at the elbow in wheelchair marathon athletes compared with non-disabled individuals, with a strong association between ulnar nerve dislocation (ulnar nerve moves anterior to the medial epicondyle with elbow flexion) and ulnar neuropathy in this population. Although questionnaire and physical examination were used in this study to make the diagnosis of ulnar neuropathy, and ultrasound was used primarily to assess for ulnar nerve dislocation, it should be noted that ultrasound is commonly used to diagnose ulnar neuropathy at the elbow. An increased maximum cross-sectional area of the ulnar nerve across the elbow on ultrasound is a common diagnostic finding in ulnar neuropathy. Ultrasound can add diagnostic accuracy to the clinical and electrodiagnostic evaluation by revealing specific anatomic pathology or by aiding in localization; however, the accuracy of neuromuscular ultrasound is not sufficient to replace clinical or electrodiagnostic examination.

One practical application for ultrasound may be in the setting of ulnar nerve subluxation or dislocation, also known as ulnar nerve hypermobility. Ulnar nerve hypermobility has been reported in as many as 37% of individuals. A wheelchair user whose ulnar nerve subluxes or dislocates with approximately 90° of elbow flexion may be advised to avoid resting their elbows on the armrest and to avoid prolonged elbow flexion positions to prevent excessive pressure on the ulnar nerve, as it is more vulnerable than an ulnar nerve that is positioned normally in the epicondylar groove.

Multiple studies have found an increased prevalence of carpal tunnel syndrome in wheelchair athletes because of repetitive wrist motions and specifically wrist flexion. It is the most common cause of wrist and hand pain in wheelchair users with paraplegia. Carpal tunnel syndrome is an entrapment neuropathy of the median nerve at the wrist that may cause pain, paresthesias, and/or weakness. Ultrasound has proven to be a valuable tool for diagnosing carpal tunnel syndrome. An increased maximum cross-sectional area of the median nerve across the wrist is a common diagnostic ultrasound finding in carpal tunnel syndrome ( Fig. 3 ).

Ultrasound image of carpal tunnel syndrome in a wheelchair athlete. Median nerve at the wrist ( dotted line ) in short axis reveals increased nerve maximum cross-sectional area (16 mm ²).

Although most studies on carpal tunnel syndrome and wheelchair athletes have used electrodiagnostic criteria, at least 2 studies have used ultrasound as a diagnostic tool. Impink and colleagues used ultrasound to measure the median nerve cross-sectional area, flattening ratio, and swelling ratio before and after a wheelchair basketball game. Physical examination maneuvers were then used between participants with and without positive ultrasound findings. Wheelchair propulsion caused notable alterations in median nerve characteristics, including a change in cross-sectional area. Additionally, participants with carpal tunnel syndrome exhibited distinct changes in median nerve swelling and had significantly longer wheelchair use durations compared to those without symptoms that met sonographic criteria of carpal tunnel syndrome.

Although electrodiagnostic testing remains the gold standard for diagnosis of carpal tunnel syndrome, ultrasound measurement of median nerve cross-sectional area at the wrist is established as accurate for the diagnosis of carpal tunnel syndrome. Given the high prevalence of carpal tunnel syndrome in the wheelchair athlete population, ultrasound can be a valuable tool for early diagnosis of symptoms to implement treatment strategies and prevent symptom progression.