The diagnosis of VEO is based on the athlete’s thorough history, physical examination, and radiographic studies. Throwers with VEO typically complain of pain at the tip of the elbow in the deceleration and follow-through phases of throwing and inability to throw at full speed and loss of ball control. This is different from the throwers only with medial instability symptoms, who experience pain at the medial side during the acceleration phase of throwing. Throwers with VEO will notice a sharp posterior pain exacerbated by forced extension or even a snapping or locking sensation as they release the ball. This pain typically increases over time and only manifests with throwing and not with other activities of daily living. Occasionally, there is associated stress on the ulnar nerve, which is vulnerable to the same stresses and overload that lead to VEO. This can present as numbness or tingling in the ring and little fingers, with clumsiness and weakness in gripping.

Physical examination begins with careful inspection. Any swelling of the elbow, change of the carrying angle (increased valgus), or loss of normal extension should be inspected. However, elbow flexion contracture has been seen in up to 50 % of professional throwers and should not be considered indicative of injury [5]. Palpation of the posterior aspect of the elbow is an important aspect of the physical examination of the thrower’s elbow. Tenderness on the olecranon tip and in the olecranon fossa in full extension suggests the presence of VEO. On the other hand, tenderness in the posterior region that is more proximal or distal to the olecranon tip may present in triceps tendinitis or olecranon stress fracture, respectively. The end-feel to range of motion test is also important in examining thrower’s elbow. The normal end-feel in extension should be the firm sensation, and the end-feel in flexion should be that of soft tissue. If a throwing athlete has a bony end-feel in terminal flexion, a bony osteophyte or loose bodies should be considered, and if a soft end-feel in extension, a soft tissue contracture should be considered [4].

We typically perform the extension jerk test (valgus extension overload test) and the extension impingement test to diagnose VEO. The extension jerk test is performed with the patient seated and the shoulder in slight forward flexion. The examiner repeatedly forces the slightly flexed elbow rapidly into full extension while applying a valgus stress. This maneuver attempts to reproduce pain with impingement of the posteromedial tip of the olecranon on the medial wall of the olecranon fossa. A positive finding often indicates the presence of a posteromedial olecranon osteophyte, which may occasionally be palpable at the time of physical examination or inflammation around olecranon fossa. In addition, the extension impingement test is performed by applying continuous extension forces to the elbow. If the pain occurs at the posterior aspect of elbow and it reproduces the pain or symptoms they experience during throwing, the posterior impingement by the olecranon tip osteophytes can be considered.

In addition, evaluation of elbow medial stability could be performed to check if there is any laxity or injury in the ulnar collateral ligament. Specific test for medial stability includes the moving valgus stress test and the milking maneuver. The moving valgus stress test is the test which the examiner applies a constant valgus force to the elbow and then quickly extends the elbow starting with the arm in full flexion. The milking maneuver is performed by having the patient reach under his injured arm with the opposite hand and grab the thumb of the injured arm. Continued pulling will place a valgus stress on the elbow under examination with palpating the ulnar collateral ligament in approximately 60° of flexion. Reproduction of painful symptoms with an apprehension-like response during the test suggests a problem in the ulnar collateral ligament. In such a case, the staged treatment for the insufficient ulnar collateral ligament such as ligament reconstruction can be considered.

Careful examination of the other susceptible structures of the elbow should be performed. Specifically, palpation of the ulnar nerve, the ulnar collateral ligament, the distal medial triceps, the flexor-pronator muscle mass, the radial head, and the capitellum should be conducted to ensure that these structures are not involved in the process. The ulnar nerve can also be the source of posteromedial pain within the cubital tunnel. The examiner should ensure that the ulnar nerve is stable within the cubital tunnel throughout the range of motion and that no ulnar nerve-distribution symptoms are present.

Standard plain radiographs of the thrower’s elbow includes AP, lateral, axial, and two oblique views of the affected side. An oblique axial view with the elbow in 110° of flexion is helpful to demonstrate posteromedial olecranon osteophytes [6]. The presence of olecranon osteophytes, osteochondral damage, or loose bodies can be visualized on these plain radiographs. However, the absence of osteophytes or loose bodies cannot rule out VEO, as the condition of posteromedial impingement predates the formation of osteophytes. We typically perform three-dimensional CT scan of elbow joint to evaluate the extent of posteromedial impingement accurately and decide the excision level of the olecranon before surgery if indicated. In addition, the CT scan can be helpful for detecting stress fractures of the olecranon and avulsion fractures of medial epicondyle. In cases where the injury of ulnar collateral ligament is suspicious, MRI can be obtained to evaluate the status of ulnar collateral ligament and other pathology within the elbow. The attenuation of the ulnar collateral ligament may accompany the VEO.

The arthroscopic pathology of VEO syndrome includes the presence of posteromedial olecranon osteophyte, chondromalacia, osteochondral damage, or loose bodies. During arthroscopic treatment, the olecranon osteophyte should be resected, loose bodies should be removed, and unstable cartilage flaps or cartilage defects may be debrided.

Initial treatment consists of active rest and anti-inflammatory medication to relieve the pain and modification of the activity that initially caused the problem. Active rest includes discontinuing throwing and avoiding any exercise that causes discomfort. Strengthening exercise to increase the flexor-pronator strength and gradual return to throwing through an interval throwing program will be allowed as symptoms resolve. For those with long duration and multiple episodes of symptoms, a more prolonged period of rest followed by a more gradual interval throwing program may be indicated.