MANUAL MINORS
Hip prosthesis dislocation is a common complication following total hip arthroplasty (hip replacement), where the prosthetic head dislocates from the artificial acetabulum.
It generally occurs within the first weeks or months after surgery, when soft tissues have not yet fully healed, although it can also present later due to component wear or trauma.
Diagnosis
The patient typically presents with acute hip pain, inability to move the affected leg, and visible deformity, similar to a traumatic dislocation. The limb may appear shortened, with internal rotation if it is a posterior dislocation or external rotation if it is an anterior dislocation.
The diagnosis is confirmed with hip X-rays, showing the prosthetic femoral head displaced from the acetabulum. In some cases, a computed tomography (CT) scan may be needed to assess the position of the prosthetic components.
Differential Diagnosis
Condition | Key Differentiation |
|---|---|
Prosthetic infection | Chronic pain with inflammatory signs and fever, no visible displacement on imaging |
Periprosthetic fracture | Acute pain with component displacement and visible fracture on X-rays |
Prosthetic loosening | Progressive pain with prosthetic instability on imaging, but no complete dislocation |
Avascular necrosis of the femoral head | Not applicable in patients with a total prosthesis, though possible in hemiarthroplasty patients |
Trochanteric tendinitis | Lateral hip pain without instability or changes in the prosthesis visible on X-rays |
Emergency Management
In the emergency setting, the patient should be stabilised, given adequate analgesia, and a closed reduction should be performed as soon as possible under sedation or general anaesthesia. The reduction manoeuvre is similar to that used for traumatic hip dislocation, with techniques varying depending on the direction of the dislocation (posterior or anterior).
If closed reduction is not possible or there is doubt about the stability of the prosthesis, open reduction is indicated. Post-reduction, control X-rays are obtained to confirm the correct positioning of the components.
Definitive Treatment
Definitive treatment involves closed reduction if the prosthesis is in good condition. Subsequent management includes rest and movement restrictions to prevent recurrence, such as limiting hip flexion beyond 90 degrees, adduction, and internal rotation.
In cases of recurrent dislocations, revision surgery may be necessary to adjust the prosthetic components or implement modifications such as larger femoral heads or dual mobility liners, which increase prosthesis stability.
Physiotherapy is crucial during recovery, focusing on strengthening the abductor and hip stabilising muscles to prevent future dislocations. Regular clinical and radiological follow-up is necessary to monitor the integrity and functionality of the prosthesis.
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