When more obvious and common causes of elbow pathology are ruled out, it is important to be aware of uncommon causes of elbow pain in throwers. The Lacertus syndrome can be a debilitating problem when overlooked; however, it can be easily diagnosed with a careful history and physical examination. If the description suggests a postexertional compartment-like problem, consider having the patient throw before the examination, and the diagnosis becomes easier to either confirm or rule out. Once the diagnosis is established treatment includes rest or fasciotomy. Recovery is uncomplicated and athletes can return to throwing within a month.
Key points
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It is important to take a complete history and perform a careful examination in order to avoid confirmation bias when evaluating throwers with medial elbow pain. Lacertus syndrome is a postexertional compartment syndrome, and the history can help elucidate this.
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The Lacertus syndrome is more common than pronator syndrome, which involves the median nerve, and can be distinguished with a careful workup. Other more common pathologies should be ruled out with a routine workup.
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Include inspection of the flexor pronator muscle group and consider evaluating after throwing when examining a thrower with postexertional elbow pain.
History of the technique
In 1959, George Bennett summarized his experiences caring for throwing athletes. The following paragraph is excerpted in its entirety from that article.
“There is a lesion which produces a different syndrome. A pitcher in throwing a curveball is compelled to supinate his wrist with a snap at the end of his delivery. On examination, one will note distinct fullness over the pronator radii teres. These are covered by a strong fascial band, a portion of which is the attachment of the biceps, which runs obliquely across the pronator muscle. A pitcher may be able to pitch for two or three innings but then the pain and swelling become so great that he has to retire. A simple linear and transverse division of the fascia covering the muscles has relieved tension on many occasions and rehabilitated these men so that they were able to return to the game.”
This is the first known reference to a condition that has undoubtedly disabled many players and possibly ended careers of an untold number of throwing athletes. Although Bennett did not fully understand the causes or even the mechanics involved (ie, he thought the pitcher supinates instead of pronates on release of the baseball), he did describe a simple operative treatment that has allowed us to prolong the careers of throwing athletes. To help distinguish this condition from pronator teres syndrome that involves compression of the median nerve, we have named it the lacertus syndrome.
History and physical examination
Athletes with the lacertus syndrome usually present with a vague history of slowly increasing discomfort in the flexor-pronator muscles after throwing. The discomfort is described as an achy painful tightness of the medial elbow, which develops in the first few hours after activity. Specifically there are not any distal neurologic symptoms or findings, and a Tinel’s sign over the anteromedial elbow is not present. This would suggest pronator teres syndrome and involvement of the median nerve.
Pronator teres syndrome is an uncommon but distinct condition in which the median nerve is compressed and irritated as it courses across the elbow region. Possible areas of compression classically include between the 2 heads of the pronator muscle, beneath the lacertus fibrosus, proximal to the elbow at the ligament of Struthers, beneath the fibrous arch of the flexor digitorum superficialis, and more rarely as it crosses under the flexor palmaris longus or Gantzer muscle ( Fig. 1 ). Pertinent findings and complaints include symptoms similar to carpal tunnel syndrome and the presence of a Tinel sign at the area of the lacertus fascia and convergence of the 2 heads of the pronator teres muscle anterior and 3 to 5 cm distal to the medial epicondyle. Symptoms of pronator syndrome can also be elicited with resisted protonation and extension in symptomatic patients. One should be thorough and open minded when evaluating any athlete with elbow discomfort in an effort to avoid confirmation bias and perhaps miss the diagnosis of an uncommon condition.
In players with lacertus syndrome the symptoms early on may be minor and are often ignored. A few hours rest leads to complete relief. As the condition progresses, the symptoms may develop earlier during throwing and become more severe. Symptoms may also require longer periods of rest to resolve—days instead of hours. Just as Dr Bennett described, these symptoms may progress to the point that the player cannot continue throwing. For position players in baseball, this problem is often not debilitating; however, for pitchers it may be. Football quarterbacks complain most often during the repetition of practice but rarely after or during games. It is at the point when the symptoms have progressed to a degree that they interfere with competition that a player usually presents to the athletic trainer or doctor.
The duration of symptoms may vary markedly. In the authors’ experience with 60 patients, the duration of acute symptoms ranged from 8 hours to 4 days before resolving, only to begin again when the athlete returned to throwing. Duration of recurrent symptoms ranged from 6 months to 3 years. In all patients the symptoms were disabling if the throwing activity resumed before the acute symptoms had resolved.
The key feature of the history in patients with the lacertus syndrome is the delayed onset of symptoms, which is like that seen in exertional compartment syndromes of the leg in runners. This, together with the history of no neurologic impairment and that a period of rest allows the athlete to resume throwing without discomfort, is diagnostic. Trauma to the elbow is usually not a factor in the etiology of the lacertus syndrome. The physician should take a careful history and perform a thorough physical examination of the elbow to help rule out more common abnormalities such as medial epicondylitis, ulnar collateral ligament injuries, and cubital tunnel syndrome or ulnar neuritis. Other conditions that can cause medial elbow pain and discomfort in throwers are bicipital tendinitis and stress fractures and rarely musculocutaneous nerve entrapment. Pronator teres syndrome or intraarticular pathologies should also be considered and ruled out.
In patients who have a history of postexertional medial elbow pain and tightness and who have the lacertus syndrome as part of their differential diagnosis, it is essential to examine the player after a workout. The examination should begin with a careful inspection of the arm, looking for exaggerated contours of the medial musculature just distal to the medial epicondyle. In players with severe or advanced cases, the proximal portions of the flexor pronator muscles seem grossly swollen, and the distinct oblique band of the lacertus fibrosus is readily visible ( Fig. 2 ). The patient should be asked to flex and pronate the wrist, which may demonstrate more clearly any abnormality in the area of the lacertus fascia. Palpation of this area will likely reveal tenderness in the muscle directly beneath and just distal to the crossing fascial band. Any tenderness should be distinguished from a Tinel’s sign over the median nerve.
