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Minimum Five-Year Outcomes of Modular Dual Mobility in Primary Total Hip Arthroplasty
Colin M Baker1, Camilo Restrepo1, William J Hozack1
1Rothman Orthopaedic Institute at Thomas Jefferson University, Philadelphia, PA.
Background:
Using a modular dual-mobility (MDM) bearing in primary total hip arthroplasty (THA) has not been widely evaluated. The purpose of this study is to evaluate clinical outcomes and survivorship following MDM bearings in primary THA.
Methods:
We used our registry database for patients with an MDM bearing on primary THA, performed by 6 surgeons through supine direct lateral or direct anterior approach. MDM bearings were used most often when impingement or subluxation was present intraoperatively despite proper component position. Another indication was a patient with planned activities who might be at a higher risk of instability postoperatively.
Results:
A total of 127 MDM bearings were used in primary THA in 119 patients. Mean follow-up was 6.77 years (range 5-8.9). Five hips were revised, none of which were due to MDM bearing failure. Preoperative Hip dysfunction and Osteoarthritis Outcome Score for Joint Replacement, Veterans RAND/Short Form 12 Physical Health Score and Mental Health Score increased from 25.81 to 52.40 (P < .0001), 30.42 to 44.50 (P < .0001), and 36.21 to 52.70 (P < .0001) at latest completed survey follow-up, respectively.
Conclusion:
This MDM bearing shows excellent functional outcomes at a minimum 5 years of follow-up with no bearing-related failures. It can be an excellent choice in primary THA specifically in females where the use of increased head size to prevent instability is not possible due to anatomical restrictions and liner thickness.
Insights
Modular dual-mobility (MDM) bearings show excellent outcomes in primary total hip arthroplasty (THA). This study found no bearing failures in 127 hips over 6.77 years, indicating MDM is a viable option for hip replacement.
Area of Science:
- Orthopedic surgery
- Biomedical engineering
- Arthroplasty research
Background:
- Modular dual-mobility (MDM) bearings are not widely studied in primary total hip arthroplasty (THA).
- Assessing clinical outcomes and survivorship of MDM bearings in primary THA is crucial.
Purpose of the Study:
- To evaluate the clinical outcomes and survivorship of modular dual-mobility (MDM) bearings in primary total hip arthroplasty (THA).
Main Methods:
- A registry database of 127 primary THA cases using MDM bearings performed by 6 surgeons was analyzed.
- Indications included intraoperative impingement/subluxation and high-risk patient activity levels.
- Surgical approaches included supine direct lateral or direct anterior.
Main Results:
- Mean follow-up was 6.77 years (range 5-8.9) for 119 patients.
- Five hips required revision, none due to MDM bearing failure.
- Significant improvements were observed in Hip dysfunction and Osteoarthritis Outcome Score (HOOS), SF-12 Physical Health, and SF-12 Mental Health scores (P < .0001).
Conclusions:
- MDM bearings demonstrate excellent functional outcomes and survivorship at a minimum 5-year follow-up.
- No bearing-related failures were reported, supporting MDM as a reliable option in primary THA.
- MDM is particularly beneficial for females where anatomical restrictions limit larger head sizes to prevent instability.
