Myositis ossificans (MO) is the most frequent type of heterotopic ossification, occurring in individuals aged 20–40 years within major muscles, and roughly 75% of cases are triggered by trauma. It is most commonly present in locations with a high risk of injury, such as the quadriceps femoris, thigh abductors, and the arm’s flexor muscles, and it is infrequently found in intra-articular sites. Upper limb heterotrophic ossification is an uncommon consequence of trauma ^[1]. The Brachialis muscle is a common site of the upper limb’s localized MO. Such ossification surrounding a joint can lead to fixed deformities and total inability for a range of movements. Excision is inevitable in situations where the myositic mass interferes with everyday activities, even though the condition is supposed to be self-limiting ^[2]. A clinical diagnosis of this condition requires a high degree of suspicion. When a painless expanding mass appears following single or multiple traumas, MO should be suspected ^[3]. The clinico-radiological diagnosis should be made using radiographs or ultrasound. Our case involved an adolescent male, with an atypically big myositic mass that limited elbow mobility.

A 19-year-old male with a history of pain, swelling, and restriction of movements of the right elbow for the last 6 years. With a history of difficulty in eating and combing hair with the right hand. History of trauma to right elbow 6 years ago for which he underwent conservative native treatment with massage and bandage-old radiographs not available. No history of evening rise in temperature, weight loss, or decreased appetite. No history of bowel and bladder disturbances. No family history or previous history of cancer. Local clinical examination revealed a palpable swelling over the medial aspect of the right-side elbow joint of size approximately 7 cm × 6 cm × 3 cm with no local rise of temperature or local tenderness and the surrounding tissue boundaries were clear. There was a fixed flexion deformity of 75°. The right forearm and arm segment were noted to have muscle wasting compared to the left upper limb. There were no sensory or vascular deficits or generalized lymphadenopathy.

The standard anterior-posterior and lateral radiographs of the right elbow joint showed circumferential calcification with a radiolucent center (Fig. 1a and b). Complete blood workup and erythrocyte sedimentation rate values were within normal. Considering the age and demand of the patient, surgical excision was executed. The patient was taken up for an operative procedure under general anesthesia with the patient in a supine position and a limb abducted at the shoulder. The elbow range of motion was checked and found to have fixed flexion deformity at 75° (Fig. 2). Through the anterior approach, a 9 cm curvilinear skin incision was made. Subcutaneous tissue and deep fascia were incised in the skin incision line, muscles were retracted. Care was taken to identify the neurovascular bundle and then retracted. The irregular calcified mass was adequately exposed and was excised (Fig. 3a and b). Similarly, through the posterior approach, a skin incision was made, subcutaneous tissue, and fascia dissected, muscles retracted, and calcified mass was visualized over the olecranon process and fibrous tissue in olecranon fossa which was excised (Fig. 3c).

The elbow was mobilized intra-operatively. The post-operative period was uneventful. Elbow joint mobilization was started from day 2. There was no motor/sensory deficit. The excised sample which was sent for histopathological examination revealed lamellar bone centrally. Radio graphical examination postoperatively revealed no abnormal mass in the elbow (Fig. 4a and b). The patient was discharged in post-operative on day 10 after suture removal and was asked to continue elbow mobilization exercises. The patient underwent follow-ups at 2 weeks, 4 weeks, 6 weeks, 10 weeks, 14 weeks, 3 months, and every 6 months thereafter. He was able to return to his routine lifestyle in 10 weeks. Elbow flexion was checked and the range of movements was found to have increased to 45–90° at the 6-month follow-up (Fig. 5a and b). The patient regained function and was able to eat food and comb his hair with his right hand. The patient recovered with the best attainable functional status at 2 years. Radiographic or clinical recurrence was not detected at any follow-up.

MO traumatica matches early clinical characteristics, such as localized swelling and discomfort, with osteosarcoma. Ossification creates less pain than osteosarcoma. Upper limb heterotrophic ossification is an uncommon consequence of trauma ^[1]. The exact etiology and pathogenesis are still unknown. The differentiation of connective tissues into fully formed bone following muscle damage has been hypothesized. Muscles that are frequently stressed or injured are more specific for this kind of ossification ^[3]. The condition is said to be self-limiting, and over time, spontaneous remission might take place ^[2]. Only 10–20% of patients experience a major functional deficit ^[4]. The thighs, arms, hips, calves, and foot soles are the most frequently affected areas [5, 6]. There have also been reports of MO at a few other uncommon locations [7, 8]. In many regions of Asia, native splinting with frequent massage is still a common treatment for traumatic diseases. This method of treatment predisposes to myositis, especially around the elbow joint. Triggering factors may include burns, dislocations, bone fractures, soft-tissue trauma (which often occurs 4–12 weeks after injury), or recurrent trauma (which has been shown to occur in as many as 65% of instances). Neurogenic disorders such as brain tumors, spinal cord injuries, strokes, and other neurological etiologies can result in additional non-traumatic causes [9, 10]. In contrast to MO, radiographs of osteosarcoma exhibit periosteal elevation and cortical damage. Computerized computed tomography shows a zoning characteristic in a myositis mass during the early stages. In addition, an ultrasound reveals a less echogenic center with a hyperechoic peripheral rim that resembles an outer sheet. Radiographically, the late stage resembles fully ossified bone. A varying zonal pattern is shown by histological investigation, consisting of a center zone containing rapidly growing fibroblasts, an intermediate zone containing osteoblasts and immature osteoid bone, and a peripheral zone containing mature bone. In the later stage, the marrow space resembles mature bone and the cortex is well-organized ^[11]. It has been reported that conservative treatment, comprising physical therapy, etidronate disodium, magnesium therapy, and acetic acid iontophoresis, is effective ^[12]. A lesion should only be surgically removed if it is fully osseous, as early removal can result in local recurrence.

When a patient exhibits radiologically detectable calcification and complains of a painful lump forming in a muscle, it is necessary to rule out MO. The degree of calcification and mature bone growth varies depending on the stage of the lesion. A biopsy of the lesion can rule out malignant transformation. Surgical excision is required for the management of mature lesions. In conclusion, although MO is rarely found in intra-articular areas, early detection and intervention are crucial. Total surgical excision will lead to marvelous improvement of elbow function.

The case report underscores the importance of early identification, surgical fixation of distal humerus fractures, and patient education to prevent native splinting.