Dislocation of hemiarthroplasty after hip fracture is common and the risk is increased with posterior approach: result from a national cohort of 25,678 individuals in the Swedish Hip Arthroplasty Register.

Background and purpose - Reported revision rates due to dislocation after hemiarthroplasty span a wide range. Dislocations treated with closed reduction are rarely reported despite the fact that they can be expected to constitute most of the dislocations that occur. We aimed to describe the total dislocation rate on the national level, and to identify risk factors for dislocation.Patients and methods - We co-processed a national cohort of 25,678 patients in the Swedish Hip Arthroplasty Register, with the National Patient Register (NPR) and Statistics Sweden. Dislocation was defined as the occurrence of any ICD-10 or procedural code related to hip dislocation recorded in the NPR, with a minimum of 1-year-follow-up. In theory, all early dislocations should thereby be traced, including those treated with closed reduction only.Results - 366/13,769 (2.7%) patients operated on with direct lateral approach dislocated, compared with 850/11,834 (7.2%) of those with posterior approach. Posterior approach was the strongest risk factor for dislocation (OR = 2.7; 95% CI 2.3-3.1), followed by dementia (OR = 1.3; CI 1.1-1.5). The older the patients, the lower the risk of dislocation (OR = 0.98 per year of age; CI 0.98-1.0). Neither bipolar design nor cementless stems influenced the risk.Interpretation - The choice of posterior approach and dementia was associated with an increased dislocation risk. When hips treated with closed reduction were identified, the frequency of dislocation with use of direct lateral and posterior approach more than doubled and tripled, respectively, compared with when only revisions due to dislocation are measured.

The association of surgical approach and bearing size and type with dislocation in total hip arthroplasty for acute hip fracture.

AIMS: Patients with femoral neck fractures (FNFs) treated with total hip arthroplasty (THA) have an almost ten-fold increased risk of dislocation compared to patients undergoing elective THA. The surgical approach influences the risk of dislocation. To date, the influence of differing head sizes and dual-mobility components (DMCs) on the risk of dislocation has not been well studied. METHODS: In an observational cohort study on 8,031 FNF patients with THA between January 2005 and December 2014, Swedish Arthroplasty Register data were linked with the National Patient Register, recording the total dislocation rates at one year and revision rates at three years after surgery. The cumulative incidence of events was estimated using the Kaplan-Meier method. Cox multivariable regression models were fitted to calculate adjusted hazard ratios (HRs) with 95% confidence intervals (CIs) for the risk of dislocation, revision, or mortality, stratified by surgical approach. RESULTS: The cumulative dislocation rate at one year was 8.3% (95% CI 7.3 to 9.3) for patients operated on using the posterior approach and 2.7% (95% CI 2.2 to 3.2) when using the direct lateral approach. In the posterior approach group, use of DMC was associated with reduced adjusted risk of dislocation compared to 32 mm heads (HR 0.21 (95% CI 0.07 to 0.68); p = 0.009). This risk was increased with head sizes < 32 mm (HR 1.47 (95% CI 1.10 to 1.98); p = 0.010). Neither DMC nor different head sizes influenced the risk of revision following the posterior approach. Neither articulation was associated with a statistically significantly reduced adjusted risk of dislocation in patients where the direct lateral approach was performed, although this risk was estimated to be HR 0.14 (95% CI 0.02 to 1.02; p = 0.053) after the use of DMC. DMC inserted through a direct lateral approach was associated with a reduced risk of revision for any reason versus THA with 32 mm heads (HR 0.36 (95% CI 0.13 to 0.99); p = 0.047). CONCLUSION: When using a posterior approach for THA in FNF patients, DMC reduces the risk of dislocation, while a non-significant risk reduction is seen for DMC after use of the direct lateral approach. The direct lateral approach is protective against dislocation and is also associated with a lower rate of revision at three years, compared to the posterior approach. Cite this article: Bone Joint J 2022;104-B(7):844-851.

Post-discharge use of assistive devices following hemiarthroplasty: comparison of fracture patients with or without hip precautions.

Purpose: To describe which types of assistive devices prescribed and actually used, either due to precautions or due to true functional reasons, after hip fracture-related hemiarthroplasty.Materials and methods: About 394 patients cluster-randomized 2010-2014 at a university hospital. Control group with standard postoperative precautions to reduce dislocations, mandatory assistive devices and knee brace for 6 weeks (in cognitively impaired) compared to non-precaution group with assistive devices only if needed. Postal questionnaire at 6 weeks and 3 months.Results: Both prescription and usage of reacher were higher in the precaution group. About 55% of patients with precautions was instructed to use stocking aids, 21% continued to do so. Significantly fewer without precautions, 11%, used it at 3 months. Raised toilet seat was used by ∼40% of all pre-fracture and was prescribed to 79% with precautions. It was unchanged at 42% in non-precaution group. Nevertheless, 64% in non-precaution group used a raised toilet both at 6 weeks and 3 months. The usage persisted around 70% in precaution group. Usage of raised chair/bed were similar, even if non-precaution patients was not prescribed such. In the precaution group, 102 were prescribed a knee brace, only 5 used it at 6 weeks.Conclusions: The use of assistive devices did not follow what was prescribed from the hospital, regardless of precautions or not. The use of higher furniture was similar regardless of precautions or not. Other devices were more common in the precaution group. The compliance of knee bracing was low, and bracing should not be standard-of-care.Implications for rehabilitationHemiarthroplasty is the most common treatment of displaced femoral neck fracture in elderly. Dislocation occur in 2 to 10% of these patients, and traditionally patients have been instructed to be careful when moving their leg and to use a number of assistive devices, in order to reduce the dislocation risk.The evidence base for such precautions is weak and occupational therapy and assistive devices may be costly. The current study shows that prescriptions and instructions from occupational therapists in hospital is more or less not follow after dismissal.Assistive devices should be prescribed based on the hip fracture patient's true functional needs, and not routinely or due to arthroplasty precautions.

Hip precautions not meaningful after hemiarthroplasty due to hip fracture. Cluster-randomized study of 394 patients operated with direct anterolateral approach.

AIMS: We aimed to compare two treatment regimes, one with and one without postoperative precautions in hemiarthroplasty patients, in terms of dislocation rate and patient-reported outcome. Direct lateral approach was used. PATIENTS AND METHODS: 394 patients were included in a cluster-randomized study 2010-2014. Depending on which ward they were admitted to, they were allotted to free rehabilitation (non-precaution group, NPG, n = 226) or our conventional regime with precautions and mandatory assistive equipment (precaution group, PG, n = 168). Patients were followed during hospital stay, at 6 weeks (postal questionnaire), 3 month (visit) and 6 months (reading of medical records) by means of function tests, health-related quality of life (EQ-5D) and other patient-reported outcome measures (PROM). RESULTS: One patient in each group had dislocation(s). We found no statistically significant differences regarding in-hospital-mortality, severe adverse events, EQ5D index or other PROM. In the NPG, rehabilitation personnel had significantly shorter work effort during hospital stay (p < 0.001). 7 in the NPG and 13 of the PG had reoperations (p = 0.038), 4 and 8 had deep infections, 3 and 5 periprosthetic fractures. CONCLUSION: Rehabilitation precautions are not needed for preventing dislocation when direct lateral approach is used. Without precautions, rehabilitation personnel implement significantly shorter work effort during hospital. We found no statistically significant differences regarding PROM and complications except for somewhat more reoperations in total in the precaution group.

Reduced Revision Risk for Dual-Mobility Cup in Total Hip Replacement Due to Hip Fracture: A Matched-Pair Analysis of 9,040 Cases from the Nordic Arthroplasty Register Association (NARA).

BACKGROUND: The dual-mobility acetabular cup (DMC) has an additional bearing consisting of a mobile polyethylene component between the prosthetic head and the outer metal shell. This design has gained popularity in revision total hip arthroplasty (THA) and in primary treatment of femoral neck fractures with the anticipation of a reduced risk of THA instability. Our primary aim was to evaluate the overall revision risk of these cups on the basis of data from the Nordic Arthroplasty Register Association (NARA) database, and our secondary aim was to study specific revision causes including dislocation. METHODS: Propensity score matching for age, sex, fixation of the cup and stem, and the year of surgery (2001 to 2014) was used to match 4,520 hip fractures treated with a DMC to 4,520 hip fractures treated with conventional THA (control group). Competing risk regression analyses with revision or death as the end point were used. Revision was defined as a secondary surgical procedure in which any component of the implant was removed or exchanged. In addition, revision of the cup was analyzed. RESULTS: The DMCs had a lower risk of revision compared with conventional THA, with an adjusted hazard ratio (AHR) of 0.75 (95% confidence interval [CI] = 0.62 to 0.92). This was consistent after adjusting for surgical approach. DMCs had a lower risk of revision due to dislocation (AHR = 0.45 [95% CI = 0.30 to 0.68]) but we found no difference regarding revision for deep infection. Revision of the acetabular component, both in general and due to dislocation, was more frequent with the use of conventional cups. The risk of death was higher in the DMC group (AHR = 1.49 [95% CI = 1.40 to 1.59]). CONCLUSIONS: The use of a DMC as primary treatment for hip fracture was associated with a lower risk of revision in general and due to dislocation in particular. The total number of DMCs analyzed (4,520) likely exceeds any cohort of DMC-treated fractures published to date. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.