A 55-year-old male patient, with known type-2 diabetes mellitus, presented with
increasing pubalgia since 2 weeks.
Laboratory examination revealed moderately elevated ESR, CRP and white blood cell count.
Radiographs of the pelvis showed widening of the pubic joint and subchondral bone erosions (Fig. 1a and 1b), which were confirmed on subsequent CT of the pelvis (Fig. 2a and 2b). In addition, CT showed soft tissue swelling adjacent to the symphysis in the adductor and rectus abdominis muscles (Fig. 2c and 2d). MRI of the pelvis revealed bone marrow oedema in the iliopubic rami (Fig. 3a and 3b). After administration of gadolinium contrast, bilateral rim-enhancing collections extending from the symphysis pubis were seen along the adductor and rectus abdominis muscles (Fig. 3c, 3d and 3e). The shape of collections along the adductor muscles resembled a butterfly (Fig. 3a and 3b).
Osteomyelitis pubis is an infection of the pubic bone and joint, most frequently caused by S. aureus [1]. It’s a rare condition accounting for less than 1% of all cases of osteomyelitis [1].
The exact pathogenesis is unclear, but the infection usually arises from haematogenous dissemination and more rarely by extension of an adjacent infectious focus [2, 3]. This condition has also been called septic arthritis of the symphysis pubis, but osteomyelitis is a more correct term, because the primary site of infection is the pubic bone adjacent to the joint. The infection starts in one pubic bone and later crosses the joint to affect the contralateral pubic bone, analogous to the course of spondylodiscitis.
Potential risk factors are invasive pelvic procedures, pregnancy or delivery, gracilis-adductor tendinopathy and the presence of infectious foci elsewhere in the body which can spread haematogenously [1, 2].
The presenting symptoms and signs are nonspecific [3]. The patient complains of gradually increasing pubic pain, radiating to the groin, perineum, buttock or genital region [2]. Antalgic gait may be present as hip motion aggravates the pain [1, 3]. Inflammatory parameters are usually elevated, but their absence does not exclude the diagnosis [2]. Bacteraemia may be present [2].
Pelvic radiographs are insensitive and are normal in the early stages of the disease [1, 3]. Diastasis of the symphysis and progressive bony destruction will initially appear in one pubic ramus, while the process crosses the joint space at a later stage [3]. Diastasis is suspicious for abscess formation in the joint [3]. CT examination is more sensitive, but its false negative rate remains 10% [2]. MRI is the imaging modality of choice, with a sensitivity that approaches 100% [2]. Typical findings are joint surface irregularities, subchondral bone destruction, bone marrow oedema in the iliopubic rami, soft tissue oedema adjacent to the pubic symphysis and pus in a widened symphysis [1, 2]. After administration of gadolinium contrast, there is enhancement of the infected pubic bone and joint surface. In later stages, a soft tissue abscess will appear as a collection with peripheral enhancement. The abscesses in the adductor muscles may have a characteristic butterfly morphology [1].
Therapy of osteomyelitis pubis consists of long term intravenous administration of antibiotics [1]. In case of failure of conservative treatment, surgery may be indicated [4, 5]. Follow-up imaging is often required [3].
Our patient was successfully treated with antibiotics and follow-up was uneventful. No surgery was required.
Osteomyelitis pubis with bilateral hip adductor and rectus abdominis abscesses.
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Based on the pelvic X-ray, CT, and MRI images provided by the patient, there is evidence of bony destruction around the pubic symphysis, with irregular joint surfaces, local reduction in bone density, and soft tissue swelling. Significant abnormal marrow signals are noted in the regions of both pubic rami adjacent to the symphysis, and some images suggest a widened joint space with possible pus or fluid collections. Contrast-enhanced MRI shows enhancement in the affected bone and surrounding soft tissue, indicative of local inflammatory or infectious changes. Overall, the imaging findings are consistent with infectious destruction of the pubic symphysis region.
This is the primary diagnosis to consider. The patient has a history of type 2 diabetes, with imaging showing destructive changes in the pubic symphysis and soft tissue swelling, rapid progression, and elevated inflammatory markers, all supportive of an infectious etiology. Common pathogens include Staphylococcus aureus, spreading through the bloodstream or from adjacent infected tissues.
Degenerative changes typically present with local pain at the pubic symphysis but do not usually show significant bony destruction or signs of a soft tissue abscess. Inflammatory markers are generally not markedly elevated. These features do not fully align with the acute presentation in this case.
Bone tumors or metastases may present with bone destruction and pain, but imaging often reveals different margins or masses, and relevant tumor markers can be present. In this case, infection and inflammatory signs predominate, making a tumor less likely.
Taking into account the patient’s age, history of type 2 diabetes, clinical symptoms (increased pain in the pubic region), moderately elevated inflammatory markers, and imaging findings showing significant bony and soft tissue destruction around the pubic symphysis, the most likely diagnosis is:
Osteomyelitis of the Pubis (Infectious Pubic Symphysis).
1. Anti-Infective Therapy: Begin with empirical antibiotics covering Staphylococcus aureus, then adjust based on culture and sensitivity results. The treatment course is typically long, at least 4–6 weeks, and may extend up to 12 weeks if necessary. During treatment, closely monitor inflammatory markers and imaging changes.
2. Surgical Intervention: In cases with extensive abscess formation, unsuccessful conservative management, or significant bone destruction and worsening pain, surgical debridement, drainage, or resection of the affected bone may be necessary. However, for early infections or more localized lesions that respond well to antibiotics, conservative management often yields good outcomes.
3. Rehabilitation and Exercise Prescription:
Focus on pain relief and infection control by restricting weight-bearing or reducing excessive movement around the pubic symphysis. Bed exercises or light daily activities are recommended, avoiding prolonged walking or heavy loading.
As symptoms improve, gradually reintroduce mild core strengthening for the lower limbs, such as bridge exercises or leg lifts. Keep the movements small in range and low in intensity, avoiding excessive stress on the affected area.
Once there is clear clinical improvement and imaging suggests that the inflammation is under control, slowly increase weight-bearing activities, such as short-distance flat walking or resistance band training in a seated position (targeting inner thigh adductor muscles and core stability). Perform these exercises 3–5 times a week, 20–30 minutes each session, increasing gradually.
With further functional recovery, introduce slow, short-distance jogging or cross-training (e.g., elliptical machine, stationary bike) to continuously strengthen core and hip musculature. Avoid abrupt, intense exercise, and carefully manage workout intensity and duration.
Throughout the rehabilitation process, regular follow-up imaging is necessary to assess bone and soft tissue status. If the patient has fragile bones or compromised cardiopulmonary function, further individual adjustments to activity intensity and methods should be made to prevent falls and excessive fatigue.
Disclaimer: This report is based solely on the currently available imaging studies and clinical information, and is for reference only. It cannot replace in-person consultations or professional medical advice. For any definitive diagnosis or treatment plan, please consult the relevant specialist and undertake a comprehensive evaluation based on the actual clinical situation.
Osteomyelitis pubis with bilateral hip adductor and rectus abdominis abscesses.
