Is the position of dual-mobility cup in THA for femoral neck fractures optimal? A retrospective study

Do Dual-mobility Cups Reduce Revision Risk in Femoral Neck Fractures Compared With Conventional THA Designs? An International Meta-analysis of Arthroplasty Registries

BACKGROUND

Dual-mobility cups in THA were designed to reduce prosthesis instability and the subsequent risk of revision surgery in high-risk patients, such as those with hip fractures. However, there are limited data from clinical studies reporting a revision benefit of dual-mobility over conventional THA. Collaboration between anthroplasty registries provides an opportunity to describe international practice variation and compare between-country, all-cause revision rates for dual-mobility and conventional THA.

QUESTIONS/PURPOSES

We summarized observational data from multiple arthroplasty registries for patients receiving either a dual-mobility or conventional THA to ask: (1) Is dual-mobility use associated with a difference in risk of all-cause revision surgery compared with conventional THA? (2) Are there specific patient characteristics associated with dual-mobility use in the hip fracture population? (3) Has the use of dual-mobility constructs changed over time in patients receiving a THA for hip fracture?

METHODS

Six member registries of the International Society of Arthroplasty Registries (from Australia, Denmark, Sweden, the Netherlands, the United Kingdom, and the United States) provided custom aggregate data reports stratified by acetabular cup type (dual-mobility or conventional THA) in primary THA for hip fracture between January 1, 2002, and December 31, 2019; surgical approach; and patient demographic data (sex, mean age, American Society of Anesthesiologists class, and BMI). The cumulative percent revision and mortality were calculated for each registry. To determine a global hazard ratio of all-cause revision for dual-mobility compared with conventional THA designs, we used a pseudoindividual patient data approach to pool Kaplan-Meier prosthesis revision data from each registry and perform a meta-analysis. The pseudoindividual patient data approach is a validated technique for meta-analysis of aggregate time-to-event survival data, such as revision surgery, from multiple sources. Data were available for 15,024 dual-mobility THAs and 97,200 conventional THAs performed for hip fractures during the study period.

RESULTS

After pooling of complete Kaplan-Meier survival data from all six registries, the cumulative percent revision for conventional THA was 4.3% (95% confidence interval [CI] 4.2% to 4.5%) and 4.7% (95% CI 4.3% to 5.3%) for dual-mobility THA at 5 years. We did not demonstrate a lower risk of all-cause revision for patients receiving dual-mobility over conventional THA designs for hip fracture in the meta-analysis once between-registry differences were adjusted for (HR 0.96 [95% CI 0.86 to 1.06]). A lower proportion of dual-mobility procedures were revised for dislocation than conventional THAs (0.9% versus 1.4%) but a higher proportion were revised for infection (1.2% versus 0.8%). In most registries, a greater proportion of dual-mobility THA patients were older, had more comorbidities, and underwent a posterior approach compared with conventional THA (p < 0.001). The proportion of dual-mobility THA used to treat hip fractures increased in each registry over time and constituted 21% (2438 of 11,874) of all THA procedures in 2019.

CONCLUSION

The proportion of dual-mobility THAs in patients with hip fractures increased over time, but there was large variation in use across countries represented here. Dual-mobility cups were not associated with a reduction in the overall risk of revision surgery in patients with hip fractures. A randomized controlled trial powered to detect the incidence of dislocation and subsequent revision surgery is required to clarify the efficacy of dual-mobility cups to treat hip fractures.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Dual mobility total hip arthroplasty in the treatment of femoral neck fractures

AIMS

To evaluate the rate of dislocation following dual mobility total hip arthroplasty (DM-THA) in patients with displaced femoral neck fractures, and to compare rates of dislocation, surgical-site infection, reoperation, and one-year mortality between DM-THA and bipolar hemiarthroplasty (BHA).

METHODS

Studies were selected based on the following criteria: 1) study design (retrospective cohort studies, prospective cohort studies, retrospective comparative studies, prospective comparative studies, and randomized controlled studies (RCTs)); 2) study population (patients with femoral neck fracture); 3) intervention (DM-THA or BHA); and 4) outcomes (complications during postoperative follow-up and clinical results). Pooled meta-analysis was carried out to evaluate the dislocation rate after DM-THA and to compare outcomes between DM-THA and BHA.

RESULTS

A total of 17 studies (ten cohort studies on DM-THA and seven comparative studies of DM-THA and BHA) were selected. These studies included 2,793 patients (2,799 hips), made up of 2,263 DM-THA patients (2,269 hips) and 530 BHA patients (530 hips). In all, 16 studies were analyzed to evaluate dislocation rate after DM-THA. The cumulative dislocation rate was 4% (95% confidence interval (CI) 3 to 5). Seven studies were analyzed to compare the rates dislocation and surgical-site infection. The rate of dislocation was significantly lower in the DM-THA group than in the BHA group (risk ratio (RR) 0.3; 95% CI 0.17 to 0.53, p < 0.001, Z -4.11). There was no significant difference in the rate of surgical-site infection between the two groups (p = 0.580). Six studies reported all-cause reoperations. The rate of reoperation was significantly lower in the DM-THA group than in the BHA group (RR 0.5; 95% CI 0.32 to 0.78, p = 0.003, Z -3.01). Five studies reported one-year mortality. The mortality rate was significantly lower in the DM-THA group than in the BHA group (RR 0.58 95% CI 0.45 to 0.75, p < 0.0001, Z -4.2).

CONCLUSION

While the evidence available consisted mainly of non-randomized studies, DM-THA appeared to be a viable option for patients with displaced fractures of the femoral neck, with better reported rates of dislocation, reoperation, and mortality than BHA. Cite this article: Bone Joint J 2020;102-B(11):1457-1466.

Dual mobility total hip arthroplasty in the treatment of femoral neck fractures

Aims

To evaluate the rate of dislocation following dual mobility total hip arthroplasty (DM-THA) in patients with displaced femoral neck fractures, and to compare rates of dislocation, surgical-site infection, reoperation, and one-year mortality between DM-THA and bipolar hemiarthroplasty (BHA).

Methods

Studies were selected based on the following criteria: 1) study design (retrospective cohort studies, prospective cohort studies, retrospective comparative studies, prospective comparative studies, and randomized controlled studies (RCTs)); 2) study population (patients with femoral neck fracture); 3) intervention (DM-THA or BHA); and 4) outcomes (complications during postoperative follow-up and clinical results). Pooled meta-analysis was carried out to evaluate the dislocation rate after DM-THA and to compare outcomes between DM-THA and BHA.

Results

A total of 17 studies (ten cohort studies on DM-THA and seven comparative studies of DM-THA and BHA) were selected. These studies included 2,793 patients (2,799 hips), made up of 2,263 DM-THA patients (2,269 hips) and 530 BHA patients (530 hips). In all, 16 studies were analyzed to evaluate dislocation rate after DM-THA. The cumulative dislocation rate was 4% (95% confidence interval (CI) 3 to 5). Seven studies were analyzed to compare the rates dislocation and surgical-site infection. The rate of dislocation was significantly lower in the DM-THA group than in the BHA group (risk ratio (RR) 0.3; 95% CI 0.17 to 0.53, p < 0.001, Z −4.11). There was no significant difference in the rate of surgical-site infection between the two groups (p = 0.580). Six studies reported all-cause reoperations. The rate of reoperation was significantly lower in the DM-THA group than in the BHA group (RR 0.5; 95% CI 0.32 to 0.78, p = 0.003, Z −3.01). Five studies reported one-year mortality. The mortality rate was significantly lower in the DM-THA group than in the BHA group (RR 0.58 95% CI 0.45 to 0.75, p < 0.0001, Z −4.2).

Conclusion

While the evidence available consisted mainly of non-randomized studies, DM-THA appeared to be a viable option for patients with displaced fractures of the femoral neck, with better reported rates of dislocation, reoperation, and mortality than BHA.

Outcomes of total hip arthroplasty using dual mobility components in patients with a femoral neck fracture

AIMS

Dislocation is the most common indication for further surgery following total hip arthroplasty (THA) when undertaken in patients with a femoral neck fracture. This study aimed to assess the complication rates of THA with dual mobility components (THA-DMC) following a femoral neck fracture and to compare outcomes between THA-DMC, conventional THA, and hemiarthroplasty (HA).

METHODS

We performed a systematic review of all English language articles on THA-DMC published between 2010 and 2019 in the MEDLINE, EMBASE, and Cochrane databases. After the application of rigorous inclusion and exclusion criteria, 23 studies dealing with patients who underwent treatment for a femoral neck fracture using THA-DMC were analyzed for the rate of dislocation. Secondary outcomes included reoperation, periprosthetic fracture, infection, mortality, and functional outcome. The review included 7,189 patients with a mean age of 77.8 years (66.4 to 87.6) and a mean follow-up of 30.9 months (9.0 to 68.0).

RESULTS

THA-DMC was associated with a significantly lower dislocation rate compared with both THA (OR 0.26; 95% CI 0.08 to 0.79) and HA (odds ratio (OR) 0.27; 95% confidence interval (CI) 0.15 to 0.50). The rate of large articulations and of intraprosthetic dislocation was 1.5% (n = 105) and 0.04% (n = 3) respectively.

CONCLUSION

THA-DMC when used in patients with a femoral neck fracture is associated with a lower dislocation rate compared with conventional arthroplasty options. There was no increase in the rates of other complication when THA-DMC was used. Future cost analysis and prospective, comparative studies are required to assess the potential benefit of using THA-DMC in these patients. Cite this article: Bone Joint J 2020;102-B(7):811-821.