Young Adolescent With Restricted Arm Motion During a Preparticipation Physical Exam

Case Presentation

An otherwise healthy 15-year-old right-hand dominant football player presented to the clinic for a preparticipation examination (PPE). He denied previous sports-related injuries. It wasn’t until after an abnormal exam, did he report a non-sports related injury that occurred on a trampoline nearly 2 years prior. While on the trampoline, he attempted a front flip but over-rotated, landing in the prone position, and injuring his right arm. He recalled immediate, intense 9/10 pain in his right proximal arm. After the accident, he was evaluated in the emergency department. His X-rays at that time were negative for acute fracture of the right humerus, without any separation of the AC joint and normal alignment of the glenohumeral joint. There was no elbow joint effusion or significant soft tissue swelling. After his injury, his pain improved but he developed reduced active internal rotation which the patient and their family had assumed would resolve and did not seek further care.

The shoulder exam during his PPE revealed significantly reduced internal rotation that was asymmetric and a painful Apley test and therefore was not cleared for participation. The patient and family were initially reluctant to do further work-up, noting that he was relatively asymptomatic. However, clinicians strongly recommended further investigation with X-ray to which the family was eventually agreeable. Imaging revealed an osseous outgrowth from the medial aspect of the proximal right humeral diaphysis measuring approximately 3.3 cm × 2.4 cm. Such findings were suggestive of an osteochondroma, but advanced imaging was recommended. MRI characterized the bony outgrowth as a heterotrophic ossification center, and also revealed a Hill-Sachs deformity, Bankart lesion, and Humeral Avulsion Glenohumeral Ligament (HAGL) lesion. The bony outgrowth correlated with the location of the inferior glenohumeral ligament, suggesting a traumatic tear at the humeral insertion, creating a heterotopic ossification center within the ligament. Such a mechanism was consistent with the trampoline injury 2 years prior.

Given the severity and number of findings, our pediatric orthopedic colleagues recommended a right shoulder girdle heterotopic ossification excision procedure. This case was surgically complex, due to the outgrowth’s proximity to the brachial plexus, specifically the axillary nerve, in addition to the Anterior Circumflex Artery. Therefore, a multidisciplinary surgical team was assembled including pediatric orthopedics, ortho-hand, and plastic surgery. Ultimately, a deltopectoral approach was performed with a pectoralis major release in order to gain visualization of the medial humerus and allow excision of the outgrowth. He required 4 weeks of immobilization post-operatively and completed twice-weekly physical therapy sessions for 6 weeks. He currently has no limitations or restrictions and has been cleared to return to all activities except wrestling.

Discussion

Preparticipation examinations (PPEs) focus on screening athletes for potential cardiac symptoms with special attention to the musculoskeletal and neurological exam, ideally to allow for safe sport participation.^1,2 Though limited evidence supports its effectiveness in detecting conditions that predispose athletes to injury or illness, regular PPEs are still required by state high school athletic associations. ² This case emphasizes the importance of the PPE in detecting abnormalities through targeted physical examination. It also highlights the benefits of doing a focused history during a PPE to not miss any pertinent details. This patient’s trampoline injury was discovered only after the examination, which revealed significantly reduced internal rotation in the affected shoulder. According to the PPE Monograph 5th edition, there is a standardized history form that includes a question about previous injuries that caused an athlete to miss a game. ³ This case highlights that more specific questions about any type of injury—related to sport or not—may be beneficial to add to a PPE. For instance, providers might get more relevant information by asking: Have you had any major injuries—sport or not sport related—leading to significant pain, an Emergency Room visit or imaging studies? Without asking the right questions, providers may miss pertinent information, especially if they are pain free, which could lead to morbidity and barriers to sport participation in the future.

In this case, limited range of motion in an adolescent’s shoulder examination appropriately led to the diagnosis of a proximal humeral bony abnormality initially thought to be an osteochondroma and later determined to be a heterotopic ossification center. Osteochondromas are the most common benign pediatric bone tumor. ⁴ They generally occur spontaneously and are typically asymptomatic, but can cause pain, decreased range of motion, and pathological fracture. ⁵ Common locations include the knee, distal femur, and proximal humerus. ⁵ They are radiographically identifiable by a cartilaginous coated osteophyte typically arising from an external bony surface whose marrow cavity is continuous with that of the outgrowth. ⁵

Contrastingly, heterotrophic ossification (HO) refers to the formation of bone outside of the normal skeletal system in the surrounding soft tissue. ⁶ There are 2 types of HO: acquired and hereditary. Acquired HO typically occurs after trauma, surgery, neurological injury, or burns, and the most common locations are high trauma locations including the hip, knee, and elbow. ⁷ Hereditary HO, which includes fibrodysplasia ossificans progressiva and progressive osseous heteroplasia, is extremely rare. ⁸

The pathophysiology of HO formation is not fully understood, but thought to be multifactorial, involving increased prostaglandin activity, hypercalcemia, tissue hypoxia, prolonged immobilization, and genetics. ⁷ Specifically, HO begins with an inflammatory reaction, after trauma for example. Over time, the HO matures into aberrant bone formation in soft tissue, localized to the area of the initial trauma. HO is histologically unique in that it has a trabecular bone pattern. ⁹

Clinically significant HO incidence varies from 10% to 20% ⁹ and typically arises 3–12 weeks after a musculoskeletal injury with roentgenographic evolution occurring within 6 months for most patients. ⁶ The roentgenographic appearance of HO depends on the stage of ossification. Mature HO within muscle classically appears as a well-developed and well-demarcated radiodense mass, with a zonal ossification process. ⁸ X-ray imaging with atypical features or unclear categorization typically requires further imaging in the form of an MRI. Nearly 80% of HO have no sequela, though complications include decreased ROM, pain, peripheral nerve entrapment, pressure ulcers, fever, and erythematous rashes. ⁹ Given the manifestation and potential complications of HO, differential diagnosis often includes cellulitis, DVT, abscess hematoma, tumor (osteosarcoma, osteochondroma as previously described), hardware infection, thrombophlebitis, and osteomyelitis. ⁶

Treatment for HO can be divided into prophylactic strategies to prevent additional growth of the HO, or to improve symptoms after their development. ⁸ In the setting of trauma-related injuries, Indomethacin is most commonly used.^8,10 Low-dose radiation has also been studied as a modality to prevent HO in high-risk patients, for example, patients with hypertrophic osteoarthritis, ankylosing spondylitis, or diffuse idiopathic skeletal hyperostosis, ¹¹ and for prophylaxis against HO reccurence. ⁸ Corticosteroids temporarily relieve pain during an HO flare and may represent a new prophylaxis option. ⁸ For patients with neurogenic HO, Etidronate can be an effective therapy option. ¹² Physical therapy programs with passive ROM exercises have conflicting evidence for the prevention or mitigation of HO, but for patients with matured HO, some clinicians recommend PT to improve ROM and prevent contractures. Surgical management with complete excision, ideally performed 6 months after traumatic HO formation is reserved for extensive and symptomatically severe cases. ⁸

Conclusion

This case of a heterotopic ossification center highlights several fundamental concepts that arise from PPEs. Namely, how PPEs serve as an entry point for adolescents to interact with the healthcare system, the importance of precise and clear questions during HPI, and how simple physical exam findings—such as limitations in active range of motion—should prompt further work-up.