Intracapsular neck of femur fracture is usually evident on plain radiographs and in the case of a young patient can be treated by closed reduction and fixation. A missed diagnosis has serious consequences. Further imaging should be considered if diagnosis is in doubt.We report an interesting case highlighting this point.
A 58 year old gentleman presented to his general practitioner with a painful left hip. He was a diet-controlled diabetic and hypertensive. The pain was deep in his groin and started subsequent to a fall from his pushbike three weeks ago. An initial radiograph was reported as showing moderate degenerative changes (Fig 1) and he was commenced on analgesics. His pain worsened six weeks later. A repeat film showed early collapse of the femoral head with loss of the joint space (Fig 2), and he was referred to an orthopaedic consultant urgently. Prior to his appointment the pain worsened to the point where he could not weight-bear. After struggling with a borrowed walking frame for three days he finally presented to accident & emergency. On examination, he had a surprisingly good range of movement in the hip, with only the extremes of movement limited by pain. His radiograph showed a displaced subcapital femoral neck fracture. (Fig 3) He was treated with a total hip replacement. The histology report of the femoral head showed avascular necrosis.
Avascular necrosis of the femoral head can occur after femoral neck fracture. It is classically associated with intracapsular fractures due to tearing of the retinacular vessels. It is more common with displaced fractures as a result of more extensive disruption of vascular supply to the femoral head. Undisplaced fractures have been quoted as having an incidence of avascular necrosis at 11 percent [1, 2] and this figure increases with increasing displacement. In some cases avascular necrosis can precede the neck of femur fracture. About one third of cases of avascular necrosis are idiopathic [3]. Reported literature recommends further imaging for patients with clinical suspicion of femoral neck fracture. There are different opinions regarding the most suitable modality. Magnetic resonance imaging (MRI), computed tomography (CT), technetium bone scan, and ultrasound scan have been suggested . Most studies have favoured MRI scan, as it is well tolerated even by elderly patients and does not involve ionising radiation. It provides an early diagnosis of occult fractures and thus decreases the hospital stay by accelerating the definitive treatment. [4, 5] While Rizzo PF et al reported the MRI as accurate as bone scanning for the diagnosis of occult hip fractures [5], Schultz E et al have declared it as the only reliable investigation in case of a difficult diagnosis. [6] CT scan has similar advantages to MRI, save for the fact that it employs ionising radiation; however hairline undisplaced or impacted fractures can be missed with older scanning techniques. Bone scan has also been advocated in some other studies. A study by Holder L. E. et al shows that isotope bone scan has a high overall sensitivity (93%) and specificity (95%) in the detection of occult neck of femur fractures. [7] There are, however, concerns that if a bone scan is done too early after trauma a false negative result may occur. Whilst Holder et al suggested that patients can be imaged as soon as they present, Matin P had a different opinion. [8] According to his work, the minimum time for a positive bone scan is age-dependent; 80% of all fractures are abnormal by 24 hours and 95% by 72 hours after injury. This delay in diagnosis may have a significant impact upon patient treatment and morbidity. A bone scan may also give false positive results in the case of adjacent soft tissue trauma, degenerative joint disease, tumour or infection. [9] Ultrasonography provides a quick, cheap, non-invasive; however it relies upon a highly skilled operator identifying a cortical break and joint effusion. Our case had no obvious risk factors for avascular necrosis and had not had any previous history of problems with his hips. A missed intracapsular femoral neck fracture appears to be the most likely cause in this case. CONCLUSION: A neck of femur fracture can go undiagnosed on plain radiograph. This may have serious implications, especially in young patients. Cases of suspicious hip pain must be further investigated; MRI or bone scan is the most suitable modality.
Intracapsular fracture neck of femur
From the provided anteroposterior (AP) pelvic X-ray, both hip joints appear generally symmetrical. In the region of the right femoral neck, there is a possible sign of slight cortical discontinuity or mildly abnormal density, with unclear margins, suggesting a potential minor or occult fracture line. The joint space remains acceptable without obvious collapse or major displacement. No significant swelling of the surrounding soft tissue is noted. However, plain radiographs alone may miss early or mild femoral neck fractures.
Taking into account that the patient is a 58-year-old male with no significant history of other hip issues and only subtle findings in the femoral neck on X-ray, the most likely diagnosis is:
“Occult Femoral Neck Fracture” (with the need to remain vigilant about the risk of femoral head necrosis). Since plain radiography has its limits, if clinical symptoms and tests (e.g., percussion pain or pain on movement) suggest a possible hip fracture, further MRI or bone scan is recommended to confirm the diagnosis.
1. Treatment Strategies:
2. Rehabilitation and Exercise Prescription (FITT-VP Principle):
3. Other Considerations:
Disclaimer:
This report provides a reference analysis based on the provided medical history and imaging information. It does not replace an in-person diagnosis or the advice of a healthcare professional. If you have any questions or if your condition changes, please consult an orthopedic specialist or visit an appropriate medical institution for further examination and treatment.
Intracapsular fracture neck of femur
