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Causes of and treatment protocol for instability of total hip replacement
1Center for Arthritis and Joint Implant Surgery, University of Southern California, Los Angeles 90033, USA.
Insights
Total hip replacement dislocations can be successfully treated with closed reduction. Immediate reoperation is recommended for unstable hips to prevent repeat dislocations and further surgeries.
Area of Science:
- Orthopedic Surgery
- Biomedical Engineering
Background:
- Total hip replacement dislocation is a significant complication impacting patient well-being.
- Predictive factors for recurrent dislocations and indications for reoperation require clarification.
Purpose of the Study:
- To identify radiographic or operative findings predicting repeat total hip replacement dislocations.
- To determine causes of dislocation necessitating immediate reoperation.
Main Methods:
- Utilized a classification system for dislocations: positional, component malposition, soft tissue imbalance, or combined.
- Categorized treatments: closed reduction, reoperation, repeat dislocations with closed reduction, and multiple reoperations.
- Correlated dislocation causes with treatment outcomes.
Main Results:
- Closed reduction is an effective primary treatment for dislocations regardless of origin.
- Immediate reoperation is advised for hips unstable under anesthesia post-reduction to prevent recurrence.
- Hips with soft tissue imbalance and abductor weakness are prone to multiple operations.
Conclusions:
- Closed reduction should be the initial treatment for total hip replacement dislocations.
- Early reoperation for unstable hips minimizes the risk of recurrent dislocations.
- Consideration of constrained acetabular components may benefit hips at high risk for revision surgery.
Abstract:
Dislocation of the total hip replacement is a devastating complication, physically and mentally. It was determined whether there are radiographic or operative findings predictive of repeat dislocation and whether there are causes of dislocation that require immediate reoperation. A previously published classification of dislocations was used which evaluates (1) positional (no radiographic abnormality); (2) component malposition (femur or acetabulum), which is inadequate version or position of the acetabular or femoral component; (3) soft tissue imbalance (change in the length or displacement of the hip), which is a change in the muscle functional length of the hip; and (4) component malposition and soft tissue imbalance. Categories of treatment of dislocations were established that could be correlated to the cause of the dislocation: (1) Category I is a successful closed reduction; (2) Category II is a successful reoperation; (3) Category III is a reoperation with subsequent repeat dislocations successfully treated with closed reduction; and (4) Category IV is comprised of hips that require multiple reoperations for treatment of dislocations. The results are that any dislocation of any origin may be treated successfully with closed reduction so that this should be the first choice of treatment. To avoid multiple treatments, immediate reoperation should be performed if the hip is unstable when the patient is examined under anesthesia after the closed reduction. Hips with soft tissue imbalance and weakness of the abductor musculature, with or without component malposition, are most at risk for multiple operations. These hips may be considered for mechanical stability (constraint in the acetabular replacement) at reoperation.