Hip Joint Instability After Surgery Performed Through the Surgical Dislocation Approach.

Background: Safe surgical dislocation of the hip is a versatile approach to the hip joint with a low complication rate. Hip joint instability is a devastating complication with poor prognosis.

Methods: All hips treated surgically through the safe surgical dislocation approach were entered in a database and the complication of hip joint instability was studied prospectively from 2000 to 2021. Instability was diagnosed by intraoperative stress examination and on postoperative radiographs. The initial deformities treated, type of instability, presumed causes, treatment provided, response to the treatment, and final result were recorded as they happened during the course of the treatment. We considered patient's age, sex, body mass index (BMI), and initial diagnosis as risk factors. We evaluated the radiographs for femoral neck shortening, lack of greater trochanteric advancement, acetabular deformity, and incongruity of the hip joint. Anterior hip precautions were initiated in the middle of the study period.

Results: 22/459 hips developed hip joint instability after surgical dislocation approach performed for hip preservation. Acetabular deficiency, coxa breva, coxa valga, posterior impingement, increased anteversion, lax soft tissues, medial thigh obesity and lack of postoperative precautions seemed to contribute to instability. 50% of the hips became normal. Chondrolysis and residual subluxation were common in the others.

Conclusion: Surgical dislocation approach disrupts the soft tissue restraints of the hip and joint stability depends on bony morphology, abductor muscle tension, and postoperative precautions. Several risk factors were subjective and speculative, but awareness of all the potential risk factors and prevention and treatment options should decrease this complication.

Level Of Evidence: IV Case series.