Conversion arthroplasty of the hip: mid-term results are good

Long-term outcomes of converting fused hips to total hip arthroplasty are satisfactory: a systematic review and meta-analysis

Background

Although conversion arthroplasty of fused hips can relieve pain and provide patient satisfaction, long-term outcomes of total hip arthroplasty (THA) after hip fusion remain a subject of debate. This meta-analysis aimed to assess the effectiveness of THA for fused hips over a long period with concerns over potential complications.

Methods

A systematic search of five databases from 2000 until 2023 identified English studies evaluating THA for fused hips with at least 100 months of follow-up. Meta-analyses were conducted using random-effect models via the comprehensive meta-analysis software. Sensitivity analysis, in-depth meta-regression, Egger's test, and the trim-and-fill method were performed appropriately.

Results

The meta-analysis assessed 790 patients and 889 hips with a mean follow-up of 11 years. At the final follow-up, the mean Harris Hip Score (HHS) and leg length discrepancy (LLD) improved by 34.755 and 2.3 cm from the baseline, respectively. Regarding survival of hip fusion conversion to THA, most studies (88.8%) reported a 5-year implant survival rate of at least 90%, and the 15-year and 20-year implant survival rates, ranged between 80-90% and 70-90%, respectively. Subjective dissatisfaction with the conversion of hip fusion to THA was only 5.3%. Composite rates of revision, instability, and aseptic loosening were 13.6%, 3.8%, and 8.8%, respectively.

Conclusions

Conversion of fused hips to THA results in favourable long-term outcomes regarding HHS, LLD, survival rates, and subjective satisfaction, leading to improved quality of life in properly selected patients. However, the presence of complications should be considered when evaluating the overall success of the procedure.

Hip arthrodesis conversion to dual mobility total hip arthroplasty in a young adult using a custom-made highly-porous titanium monobloc cup: A case report

INTRODUCTION

Conversion of hip arthrodesis to total hip arthroplasty (THA) is an effective but challenging procedure to restore hip functionality and improve quality of life. Herein, a case of arthrodesis takedown to a dual mobility THA with a custom-made 3D-printed cup.

PRESENTATION OF CASE

Due to higher risk of instability and loosening for the altered and atrophic anatomy, a custom-made highly-porous titanium dual mobility monobloc cup has been used for a cementless conversion THA in 31-year-old patient with hip arthrodesis. At 3-year follow-up clinical and radiographic results were excellent with the custom-made implant found stable and well osseointegrated.

DISCUSSION

To the best of our knowledge, this is the first case of arthrodesis conversion to THA with custom-made highly-porous dual mobility cup in a young adult. The dual mobility construct helped reducing the risk of dislocation, while the highly-porous structure reduced the risk of aseptic loosening.

CONCLUSION

The use of cementless highly-porous dual mobility implant in complex cases young patients is supported.

Outcome and technical consideration of conversion total hip arthroplasty after failed fixation of intracapsular and extracapsular hip fractures: Are they really that different?

INTRODUCTION

Conversion Total Hip Arthroplasty (cTHA) is a rescue strategy for proximal femur osteosynthesis failures. However, it is unclear whether cTHAs performed for extra-capsular fracture fixation failures (ECF) or for intra-capsular fracture fixation failures (ICF) share the same complexity and efficacy. The purpose of our study was to compare cTHAs performed on pre-existing ICFs and pre-existing ECFs, focusing on surgical complications and functional outcomes in both groups.

METHODS

An observational retrospective study was conducted on cTHA patients, treated between 2014 and 2018, divided into 2 groups: ICF-group and ECF-group. The main outcomes were: type of implant used, duration of surgery, need for transfusions, incidence of complications, functional outcomes.

RESULTS

28 patients were included (15 in the ECF group and 13 in the ICF group); the average follow-up was of 31 ± 17.3 months. No significant differences were identified in terms of the type of implant used and duration of surgery. The number of transfused patients was 4 in the ICF group and 12 in the ECF group (p = 0.02); the average transfused units were 0.4 ± 0.7 in the ICF group and 1.3 ± 0.9 in the ECF group (p = 0.01). The incidence of complications - an infection and a dislocation, both of which occurred in the ICF group - and functional outcomes did not present significant differences.

CONCLUSION

The conversion surgery on ECFs patients is technically more difficult for the surgeon and prone to greater blood loss. The outcomes are satisfactory and overlap between the two groups.

The fate of positive intraoperative cultures following conversion total hip arthroplasty

INTRODUCTION

The objectives of this study are to report the rates of positive intraoperative cultures obtained during conversion total hip arthroplasty (THA) according to index surgery, and to describe the natural history of treatment for a consecutive series of patients with unexpected positive intraoperative cultures during conversion THA.

METHODS

We reviewed all patients at 2 institutions undergoing conversion THA from prior open reduction and internal fixation (ORIF) of acetabular and hip fractures or hemiarthroplasty for displaced femoral neck fractures from 2011 to 2018. Intraoperative cultures were taken in 105 patients. Positive intraoperative cultures during conversion were recorded and managed with an infectious diseases consult. The outcomes including PJI at 90 days and 1 year follow-up were documented.

RESULTS

Overall, 19 of 105 patients (18%) undergoing conversion THA had positive intraoperative cultures, with the highest rates in the hemiarthroplasty 7/16 (44%) and acetabular ORIF 9/48 (19%) groups. All 19 patients were initially treated conservatively: 8 received IV antibiotics, 10 received no additional therapy, and 1 received oral antibiotics. 4/9 acetabular fracture conversions developed PJI at 1 year, with 3 requiring multiple irrigation and debridement/polyethylene exchanges to control the infection while the 4th patient required 2-stage exchange. There were no 1-year PJI from any of the other index procedures after conversion. All 7 hemiarthroplasty patients with positive cultures were treated to resolution with 4-8 weeks IV antibiotics alone.

CONCLUSIONS

Patients undergoing conversion THA from prior hip or acetabular fracture have a high rate of positive intraoperative cultures. As such, all patients undergoing conversion THA from prior hip or acetabular fracture fixation should undergo thorough diagnostic workup prior to surgery, and have intraoperative cultures obtained during surgery if infection remains suspicious. Further work should be performed to develop MSIS criteria for preoperative management of patients undergoing conversion THA.

Prevention of Dislocation After Total Hip Arthroplasty

BACKGROUND

Prevention of dislocation after primary total hip arthroplasty (THA) begins with patient preoperative assessment and planning.

METHODS

We performed a literature search to assess historical perspectives and current strategies to prevent dislocation after primary THA. The search yielded 3458 articles, and 154 articles are presented.

RESULTS

Extremes of age, body mass index >30 kg/m², lumbosacral pathology, surgeon experience, and femoral head size influence dislocation rates after THA. There is mixed evidence regarding the effect of neuromuscular disease, sequelae of pediatric hip conditions, and surgical approach on THA instability. Sex, simultaneous bilateral THA, and restrictive postoperative precautions do not influence the dislocation rates of THA. Navigation, robotics, lipped liners, and dual-mobility acetabular components may improve dislocation rates.

CONCLUSIONS

Risks for dislocation should be identified, and measures should be taken to mitigate the risk. Reliance on safe zones of acetabular component positioning is historical. We are in an era of bespoke THA surgery.

Quantifying Blood Loss and Transfusion Risk After Primary vs Conversion Total Hip Arthroplasty

BACKGROUND

Primary total hip arthroplasty (THA) and conversion THA may result in substantial blood loss, sometimes necessitating transfusion. Despite the complexities of the latter, both are grouped in the same category for quality assessment and reimbursement. This study's purpose was to compare both blood loss and transfusion risk in primary and conversion THA and identify their associated predictors.

METHODS

A total of 1616 patients who underwent primary and conversion THA at a single hospital from 2009-2013 were reviewed (primary THA = 1575; conversion THA = 41). Demographics, comorbidities, and perioperative data were collected from electronic records. Blood loss was calculated using a validated method. Transfusion triggers were based on standardized criteria. Separate multivariable regression models for blood loss and transfusion were performed.

RESULTS

Conversion THA patients were younger (P = .002), had lower age-adjusted Charlson scores (P = .006), longer surgeries (P < .001), higher blood loss (P < .001), and more transfusions (P < .001). Primary and conversion THA groups were different in terms of surgical approach (P < .001), anesthesia type (P = .002), and venous thromboembolism prophylaxis (P = .01). Compared to primary THA, conversion THA had an average 478.9 mL higher blood loss (P = .003) and increased adjusted odds ratio of 3.2 (P = .019) for transfusion.

CONCLUSION

Conversion THA leads to higher blood loss and transfusion compared with primary THA. These differences were quantified in the present study and showed consistent results between the 2 metrics. The differences between these procedures should be addressed during quality assurance because conversion THA is associated with higher resource utilization, which is important in the allocation of resources and tiered reimbursement strategies.