MRI Evaluation of Posterior Capsular Dehiscence After Posterior Approach Total Hip Arthroplasty
Paul R Allegra1, Ane U Nuño, Carlos M Barrera
1From the Department of Orthopedic Surgery, University of Miami Miller School of Medicine, Miami, FL (Dr. Allegra, Dr. McNamara, Dr. Cohen-Levy, Dr. Rizzo, and Dr. Alba), Department of Radiology, Hospital Universitario Donostia, Donostia-SAN Sebastián, Spain (Dr. Nuño), University of Miami Miller School of Medicine (Mr. Barrera), and the Department of Radiology, University of Miami Miller School of Medicine (Dr. Ezuddin, Dr. Jose), Miami, FL.
Introduction:
To our knowledge, no previous study has evaluated the use of MRI to diagnose posterior capsule dehiscence after posterior approach total hip arthroplasty (THA) with capsular repair and its association with postoperative posterior hip dislocation.
Methods:
A retrospective chart review of patients who underwent posterior approach THA with capsulotomy repair was performed. Patients were identified who subsequently underwent MRI, and these studies were evaluated for signs of posterior capsular disruption. Each chart was then evaluated for episodes of postoperative hip dislocation.
Results:
Six hundred seventy-five patients were included in the retrospective review. Thirty-two patients (17 women [aged 37 to 78 years] and 15 men [aged 34 to 80 years]) met the inclusion criteria. Fifteen patients of 32 (48.4%) developed posterior capsule dehiscence after repair (group 1). Seventeen patients of 32 (51.6%) did not have MRI evidence of posterior capsule dehiscence (group 2). In group 1, 2 patients of 15 (13.3%) experienced a posterior hip dislocation. No group 2 patients experienced a posterior hip dislocation. Overall, only 2 patients of 32 (6.3%) developed posterior hip dislocations. In group 1, 12 patients of 15 (80%) developed dehiscence at the lateral capsule margin at the greater trochanter suture repair site. The two patients in group 1 with posterior hip dislocations displayed MRI evidence of capsular dehiscence in this region. Two patients of 15 (13.3%) in group 1 demonstrated dehiscence at the central third of the posterior capsule, whereas 1 patient of 15 (6.6%) in group 1 demonstrated dehiscence at the medial/acetabular margin. No significant difference was found between the dislocation rates between groups 1 and 2 (P = 0.212). The distribution of capsular dehiscence (lateral, middle, and medial capsule) in group 1 was significant (P = 0.0006).
Discussion:
MRI can effectively diagnose capsular dehiscence in patients who have undergone posterior THA. Most repaired capsules failed in the lateral repair region. MRI offers the potential to identify patients with a higher risk of implant dislocation.
Level Of Evidence:
Therapeutic level III.
Insights
Magnetic resonance imaging (MRI) effectively diagnoses posterior capsule dehiscence after posterior approach total hip arthroplasty (THA). This condition, often occurring at the lateral repair site, may indicate a higher risk of hip dislocation.
Area of Science:
- Orthopedic Surgery
- Radiology
- Biomedical Imaging
Background:
- Posterior approach total hip arthroplasty (THA) with capsular repair can be complicated by posterior capsule dehiscence.
- The diagnostic utility of MRI for detecting this dehiscence and its association with dislocation remains underexplored.
Purpose of the Study:
- To evaluate the effectiveness of MRI in diagnosing posterior capsule dehiscence after posterior approach THA with capsular repair.
- To investigate the association between MRI-detected capsular dehiscence and postoperative posterior hip dislocation.
Main Methods:
- Retrospective chart review of patients undergoing posterior approach THA with capsulotomy repair.
- Analysis of MRI studies for signs of posterior capsular disruption.
- Evaluation of patient charts for episodes of postoperative hip dislocation.
Main Results:
- Fifteen of 32 patients (48.4%) showed MRI evidence of posterior capsule dehiscence.
- Dehiscence occurred most frequently at the lateral capsule margin (80% of cases with dehiscence).
- Two patients (13.3%) with dehiscence experienced posterior hip dislocation; no dislocations occurred in patients without dehiscence.
Conclusions:
- MRI is a reliable method for diagnosing posterior capsule dehiscence following posterior approach THA.
- Capsular failure predominantly occurs at the lateral repair site.
- Identifying capsular dehiscence via MRI may help stratify patients at increased risk for hip dislocation.
