A 57-year-old man presented with a one-month history of severe worsening left buttock pain.
Plain radiographs of the upper thigh show a mineralised density adjacent to the posterior aspect of the femur (Fig 1). No underlying periosteal reaction or erosion of the adjacent cortex was visualised. The linea aspera was seen in profile. CT showed an irregular amorphous focus of calcification at the insertion of the gluteus maximus muscle on the linea aspera of the proximal left femur with no associated soft tissue mass, and no adjacent fluid collection (Fig 2).
Calcific tendonitis is frequently painful condition of unknown aetiology characterised by deposits of poorly mineralised hydroxyapatite (a crystalline calcium phosphate) in tendons, most commonly affecting tendons of the rotator cuff. While not always symptomatic, calcific tendonitis presents with pain and inflammation. It is proposed that calcific tendonitis progresses through four clinico-pathological phases:
1. Formulative: A portion of tendon undergoes fibrocartilagenous transformation due to an unknown trigger and chalk-like calcification is deposited in the transformed tissue.
2. Resting: Once the calcified deposit is formed it undergoes a resting phase that may or may not be painful. It may also cause mechanical symptoms at this stage.
3. Resorpitve: An inflammatory response follows due to increased vascularity at the site of the calcific deposit. Macrophages and multinucleate giant cells attempt to absorb the calcific deposit. At this stage the calcific deposit resembles toothpaste and may leak into adjacent tissues including bursae, causing painful symptoms.
4. Postcalcific: Once the calcific deposit has been resorbed, the collagen pattern of the tendon is reconstituted by fibroblasts.
Two types of calcification have been described: a localized homogenous deposit with well defined borders and a more diffuse, amorphous deposit with an ill-defined periphery that has been associated with the more symptomatic resorptive phase. Although often subtle, plain radiographs may show calcific deposits in characteristic locations of tendon insertion. CT, Ultrasound and MRI are utilized to define the location, distribution and morphology of the calcification, the relationship to and integrity of the adjacent tendon and any associated inflammatory reaction occurring in the adjacent bone.
A number of published descriptions have shown calcific tendinitis at the gluteus maximus insertion (1-3), an uncommon site for this disorder. Atypical and aggressive features have been described in association with calcific tendonitis at this location (4), which is often mistaken by those unfamiliar with this diagnosis for an aggressive process such as surface osteosarcoma.
Treatment includes conservative treatment exercise and physiotherapy and symptomatic relief with analgesic and anti-inflammatory medications. Needling and aspiration (barbotage) with injection of steroid and local anaesthetic has been used to good effect (5). Surgery has been performed in refractory cases.
In the correct clinical setting with the classical imaging appearances, there is rarely a differential diagnosis. Imaging appearances can be atypical however and the calcific deposit may cause underlying osseous erosion. In these cases CT and MRI can be used to further evaluate these lesions.
Calcific tendonitis of gluteus maximus insertion
From the provided X-ray and CT images of the left sacroiliac region and proximal femur, there is a high-density lesion visible within the soft tissue of the left gluteal region. The lesion is relatively well-defined, partially clear in boundary, showing calcification-like changes and located near the insertion of the gluteus maximus tendon.
On the X-ray, a localized calcification can be observed within the soft tissue, though the demarcation from the cortical bone is still discernible.
The axial and coronal CT reconstruction images show that the calcified focus is closely related to the adjacent tendon origin and insertion, and varying degrees of density changes can be seen in the surrounding soft tissue, suggesting local inflammatory reaction or exudation. No obvious bone destruction or periosteal reaction is noted.
Considering the patient’s age (57-year-old male), symptoms (progressive pain in the left gluteal region for 1 month), and imaging findings (marked calcification at the tendon insertion with surrounding soft tissue inflammatory reaction), the most likely diagnosis is Calcific Tendinitis of the Gluteus Maximus Tendon. If there is any clinical uncertainty, further MRI examination or dynamic ultrasound could be performed to evaluate local soft tissue and tendon injuries. Image-guided aspiration or biopsy may be considered if necessary for confirmation.
1. Conservative Treatment:
• Initially, conservative management is advised, including rest, avoidance of excessive weight-bearing, and prevention of repeated irritation of the painful area.
• According to medical advice, non-steroidal anti-inflammatory drugs (NSAIDs) or other analgesics may be used to relieve pain and inflammation.
• Local physical therapy (e.g., warm compresses, ultrasound therapy) can improve blood flow and speed up repair.
• In cases of significant symptoms, ultrasound-guided lavage or “barbotage” could be considered, combined with local anesthesia and steroid injection to reduce inflammation and pain.
2. Surgical Treatment:
• For cases where conservative treatment is ineffective and the pain persists or significantly affects daily activities, surgical removal of the calcific deposits and repair of the damaged tendon tissue can be considered.
• The timing and method of surgery should be determined after a comprehensive evaluation of imaging findings, the severity of pain, and the patient’s preference.
3. Rehabilitation/Exercise Prescription:
After pain relief or during conservative treatment, gradual restoration of hip and gluteal muscle function is essential. The following principles (FITT-VP) can be applied during rehabilitation:
① Type of Exercise (Type): Basic functional training that does not exacerbate local pain, such as seated or supine active hip movements, and low-resistance band exercises focusing on gluteal muscle contraction.
② Frequency (Frequency): 3–5 times per week, adjusted according to pain and fatigue levels.
③ Intensity (Intensity): Start with low intensity (e.g., light resistance band training), limiting each session to a maximum of 30 minutes, and gradually increase resistance. If pain worsens, reduce or pause the activity.
④ Time (Time): Approximately 30 minutes per session, subdivided into sets (e.g., 5–10 minutes per set) with 1–2 minutes of rest in between.
⑤ Progression (Progression): Once pain decreases and muscle strength and range of motion improve, incrementally increase resistance (medium resistance bands or light weights), and introduce functional exercises (e.g., light squats, hip extension drills).
⑥ Volume (Volume): Adjust the total volume based on individual recovery and fatigue levels, consistently monitoring pain and joint mobility.
If marked pain or discomfort occurs during training, stop immediately and consult a rehabilitation specialist or the treating physician to ensure safety. Patients with underlying degenerative changes or other chronic diseases should maintain low-impact, low-load exercise programs and have regular follow-up.
Disclaimer: This report serves as a reference for medical analysis only and cannot replace an in-person consultation or professional medical advice. If you have any questions or if your symptoms worsen, please seek medical attention promptly.
Calcific tendonitis of gluteus maximus insertion
