Conversion of Fused Hip to Total Hip Arthroplasty: Long-Term Clinical and Radiological Outcomes

BACKGROUND

Despite promising results at the mid-term followup, several aspects of conversion of the fused hip to total hip arthroplasty (THA) remain controversial. The aim of this study was to evaluate clinical and radiological outcomes with a minimum 5-year followup in patients who underwent conversion of the fused hip to THA.

METHODS

Fifty-seven patients (59 hips) were evaluated. The Harris Hip Score (HHS), range of motion (ROM), and the Visual Analogue Scale (VAS) were used to assess hip function and low back pain. Subjective satisfaction with surgery and the presence of the Trendelenburg sign was also evaluated. Radiological assessment was performed pre- and postoperatively to evaluate loosening and heterotopic ossification (HO).

RESULTS

After a mean followup of 13.0 ± 6.2 years, HHS and VAS significantly improved from 46.0 ± 16.7 to 80.8 ± 18.8 and from 4.4 ± 1.5 to 2.1 ± 1.4 (both P < .001), respectively. Twenty-three patients (40.4%) had a positive Trendelenburg sign, and HOs were found in 29 cases (49.1%). An overall 29.8% complication rate was noted. Smoking habits and rheumatoid arthritis were predictive of Trendelenburg sign (P = .046 and P = .038, respectively). Implant survival rate as the end point was 98.7 ± 1.3% at 5 years, 92.4 ± 3.3% at 10 years, 82.1 ± 5.7% at 15 years, and 73.4 ± 8.0% at 20 and 25 years. A worse cumulative implant survival rate was noted in patients who underwent previous hip surgery, defined as any hip operation before fusion (P = .005).

CONCLUSION

Conversion of the fused hip to hip arthroplasty provides high levels of hip functionality and satisfaction with surgery at long-term followup. An implant survival rate higher than 70% can be expected 25 years postoperatively.

Alternative Payment Models Should Risk-Adjust for Conversion Total Hip Arthroplasty: A Propensity Score-Matched Study

BACKGROUND

For Medicare beneficiaries, hospital reimbursement for nonrevision hip arthroplasty is anchored to either diagnosis-related group code 469 or 470. Under alternative payment models, reimbursement for care episodes is not further risk-adjusted. This study's purpose was to compare outcomes of primary total hip arthroplasty (THA) vs conversion THA to explore the rationale for risk adjustment for conversion procedures.

METHODS

All primary and conversion THAs from 2007 to 2014, excluding acute hip fractures and cancer patients, were identified in the National Surgical Quality Improvement Program database. Conversion and primary THA patients were matched 1:1 using propensity scores, based on preoperative covariates. Multivariable logistic regressions evaluated associations between conversion THA and 30-day outcomes.

RESULTS

A total of 2018 conversions were matched to 2018 primaries. There were no differences in preoperative covariates. Conversions had longer operative times (148 vs 95 minutes, P < .001), more transfusions (37% vs 17%, P < .001), and longer length of stay (4.4 vs 3.1 days, P < .001). Conversion THA had increased odds of complications (odds ratio [OR] 1.75; 95% confidence interval [CI] 1.37-2.24), deep infection (OR 4.21; 95% CI 1.72-10.28), discharge to inpatient care (OR 1.52; 95% CI 1.34-1.72), and death (OR 2.39; 95% CI 1.04-5.47). Readmission odds were similar.

CONCLUSION

Compared with primary THA, conversion THA is associated with more complications, longer length of stay, and increased discharge to continued inpatient care, implying greater resource utilization for conversion patients. As reimbursement models shift toward bundled payment paradigms, conversion THA appears to be a procedure for which risk adjustment is appropriate.

Hip Arthroplasty After Surgical Treatment of Intertrochanteric Hip Fractures

BACKGROUND

Although use of intramedullary hip screws (IMHS) for intertrochanteric (IT) hip fractures has become more common, limited data have suggested difficulties in conversion to hip arthroplasty. The present study investigates whether conversion of failed IT fracture fixation with an intramedullary vs extramedullary device leads to different rates or types of complications or decreased arthroplasty survivorship.

METHODS

One hundred eleven patients were converted to hip arthroplasty after previous surgical treatment of an IT fracture from 2000 to 2010. Seventy hips had been treated with an extramedullary fixation device (EFD) and 41 with an IMHS.

RESULTS

Length of hospital stay and operative times were similar (6 days and 206 minutes for EFD vs 6 days and 208 minutes for IMHS; P > .7). The presence of a Trendelenburg gait at last clinical follow-up was similar between groups (37% in EFD group and 38% in IMHS group). Five-year survivorship free of revision was 95% in the EFD group and 94% in the IMHS group (P = 1.0). The overall complication rate was similar (21% for EFD vs 27% for IMHS; P = .51) between groups. The most common complication was late periprosthetic fracture in the EFD patients (6% vs 0% in IMHS; P = .29) and intraoperative femoral fracture in the IMHS patients (12% vs 1% in EFD; P = .02).

CONCLUSION

The short-term survivorship of conversion hip arthroplasty after surgical treatment of an IT fracture is excellent regardless of original fracture fixation method. If early complications, particularly periprosthetic fractures, can be minimized, the likelihood of a successful outcome is high. The risk of intraoperative femoral fracture was greater during conversion from an IMHS compared to an EFD.