Surgical approach had minor association with femoral stem migration in total hip arthroplasty: radiostereometric analysis of 61 patients after 5-year follow-up.

BACKGROUND AND PURPOSE: Total hip arthroplasty (THA) is usually performed using 1 of 3 surgical approaches: direct lateral (DLA), posterior (PA), or anterior (AA). AA is different from DLA and PA owing to limited intraoperative visibility of the femoral canal. This could affect stem positioning and therefore migration. We aimed to perform an exploratory radiostereometric analysis (RSA) study with 3 groups for surgical approach assessing stem migration up to 5 years postoperatively. PATIENTS AND METHODS: 61 patients with unilateral osteoarthritis of the hip were included. 21 patients were allocated to the DLA, 20 to the PA, and 20 to the AA group. All patients received an uncemented, collarless, double-tapered, fully hydroxyapatite-coated Profemur Gladiator stem. Migration was measured with model-based RSA. Baseline RSA was on day 1 postoperatively. The follow-ups were at day 8, at 5 weeks, and at 3, 6, 12, 24, and 60 months after surgery. Generalized linear mixed models were used to analyze maximum total point motion (MTPM) migrations. RESULTS: Group mean differences in MTPM were 0.4 mm (95% confidence interval [CI] -1.5 to 2.4) for DLA vs. PA, 1.1 mm (CI -1.0 to 3.3) for AA vs. DLA, and 1.6 mm (CI -0.8 to 3.9) for AA vs. PA, when adjusted for sex and age as covariates. 2 stems in the AA group had excessive early migration. For all stems the migrations occurred mainly within 5-week follow-up and then stabilized. CONCLUSION: At 5-year follow-up, there were no statistically significant differences in stem migration associated with the 3 surgical approaches used in this study.

30-day mortality in patients after hip fracture surgery: A comparison of the Charlson Comorbidity Index score and ASA score used in two prediction models.

OBJECTIVE: To compare the Charlson Comorbidity Index (CCI) and American Society of Anesthesiologists (ASA) Physical Status Classification used in two prediction models for 30-day mortality after hip fracture surgery. STUDY DESIGN AND SETTING: Data from 3651 patients (mean age: 83 years) from a Norwegian University Hospital were retrospectively obtained and randomly divided into two cohorts: a model cohort (n = 1825) to develop two prediction models with CCI and ASA as the main predictors, and a validation cohort (n = 1826) to assess the predictive ability of both models. A receiver operating characteristic (ROC) curve determined the best model to predict mortality. RESULTS: Area under the ROC curve at 30 days was 0.726 (p = 0.988) for both the CCI- and ASA-model. The chosen cut-off-points on the ROC curve for CCI- and ASA-model corresponded to similar model sensitivities of 0.657 and specificities of 0.680 and 0.679, respectively. Hence, each model predicts correctly 66% (n = 96) of the mortalities and 68% (n = 1132 and n = 1131) of the survivals. 23% (n = 33) of the mortalities were predicted by neither model. CONCLUSION: The CCI- and ASA-model had equal predictive ability of 30-day mortality after hip fracture. Considering the effort involved in calculating Charlson Comorbidity Index score, the ASA score may be the preferred tool to predict the 30-day mortality after hip fracture.

Health care services and costs after hip fracture, comparing conventional versus standardised care: A retrospective study with 12-month follow-up.

AIMS: To compare costs related to a standardised versus conventional hospital care for older patients after fragility hip fracture and determine whether a shift in hospital care led to cost-shifts between specialists and primary health care. METHODS: We retrospectively collected and calculated volumes of care and accompanying costs from fracture time until 12 months after hospital discharge for 979 patients. All patients aged ≥ 65 years had fragility hip fractures. The data set had few missing data points because of the patient registry, administrative databases, and a low migration rate. RESULTS: Total costs per patient at 12 months were EUR 78 164 (standard deviation [SD] 58 056) and EUR 78 068 (SD 60 131) for conventional and standardised care, respectively (p = 0.480). Total specialist care costs were significantly lower for the standardised care group (p < 0.001). Total primary care costs were higher for the standardised care group (p = 0.424). Total costs per day of life for the conventional and standardised care groups were EUR 434 and EUR 371, respectively (p = 0.003). Patients in the standardised care group had 17 more days of life. CONCLUSIONS: Implementation of a standardised care to improve outcomes for patients with hip fracture caused lower specialist care costs and higher primary care costs, indicating care- and cost-shifts from specialist to primary health care.

Mortality and readmission following hip fracture surgery: a retrospective study comparing conventional and fast-track care.

OBJECTIVE: To compare the efficacies of two pathways-conventional and fast-track care-in patients with hip fracture. DESIGN: Retrospective single-centre study. SETTING: University hospital in middle Norway. PARTICIPANTS: 1820 patients aged ≥65 years with hip fracture (intracapsular, intertrochanteric or subtrochanteric). INTERVENTIONS: 788 patients were treated according to conventional care from April 2008 to September 2011, and 1032 patients were treated according to fast-track care from October 2011 to December 2013. PRIMARY AND SECONDARY OUTCOME: Primary: mortality and readmission to hospital, within 365 days follow-up. Secondary: length of stay. RESULTS: We found no statistically significant differences in mortality and readmission rate between patients in the fast-track and conventional care models within 365 days after the initial hospital admission. The conventional care group had a higher, no statistical significant mortality HR of 1.10 (95% CI 0.91 to 1.31, p=0.326) without and 1.16 (95% CI 0.96 to 1.40, p=0.118) with covariate adjustment. Regarding the readmission, the conventional care group sub-HR was 1.02 (95% CI 0.88 to 1.18, p=0.822) without and 0.97 (95% CI 0.83 to 1.12, p=0.644) with adjusting for covariates. Length of stay and time to surgery was statistically significant shorter for patients who received fast-track care, a mean difference of 3.4 days and 6 hours, respectively. There was no statistically significant difference in sex, type of fracture, age or Charlson Comorbidity Index score at baseline between patients in the two pathways. CONCLUSIONS: There was insufficient evidence to show an impact of fast-track care on mortality and readmission. Length of stay and time to surgery were decreased. TRIAL REGISTRATION NUMBER: NCT00667914; results.

Similar migration in computer-assisted and conventional total knee arthroplasty.

Background and purpose - Computer-assisted surgery (CAS) in total knee arthroplasty (TKA) has been used in recent years in the hope of improving the alignment and positioning of the implant, thereby achieving a better functional outcome and durability. However, the role of computer navigation in TKA is still under debate. We used radiostereometric analysis (RSA) in a randomized controlled trial (RCT) to determine whether there are any differences in migration of the tibial component between CAS- and conventionally (CONV-) operated TKA. Patients and methods - 54 patients (CAS, n = 26; CONV, n = 28) with a mean age of 67 (56-78) years and with osteoarthritis or arthritic disease of the knee were recruited from 4 hospitals during the period 2009-2011. To estimate the mechanical stability of the tibial component, the patients were examined with RSA up to 24 months after operation. The following parameters representing tibial component micromotion were measured: 3-D vector of the prosthetic marker that moved the most, representing the magnitude of migration (maximum total point motion, MTPM); the largest negative value for y-translation (subsidence); the largest positive y-translation (lift-off); and prosthetic rotations. The precision of the RSA measurements was evaluated and migration in the 2 groups was compared. Results - Both groups had most migration within the first 3 months, but there was no statistically significant difference in the magnitude of the migration between the CAS group and the CONV group. From 3 to 24 months, the MTPM (in mm) was 0.058 and 0.103 (p = 0.1) for the CAS and CON groups, respectively, and the subsidence (in mm) was 0.005 and 0.011 (p = 0.3). Interpretation - Mean MTPM, subsidence, lift-off, and rotational movement of tibial trays were similar in CAS- and CONV-operated knees.

Muscular strength after total hip arthroplasty. A prospective comparison of 3 surgical approaches.

BACKGROUND AND PURPOSE: Minimizing the decrease in muscular strength after total hip arthroplasty (THA) might allow patients to recover faster. We evaluated muscular strength in patients who were operated on using 3 surgical approaches. PATIENTS AND METHODs: In a prospective cohort study, 60 patients scheduled for primary THA were allocated to the direct lateral, posterior, or anterior approach. Leg press and abduction strength were evaluated 2 weeks or less preoperatively, 2 and 8 days postoperatively, and at 6-week and 3-month follow-up. RESULTS: Differences in maximal strength change were greatest after 2 and 8 days. The posterior and anterior approaches produced less decrease in muscular strength than the direct lateral approach. 6 weeks postoperatively, the posterior approach produced greater increase in muscular strength than the direct lateral approach, and resulted in a greater increase in abduction strength than the anterior approach. At 3-month follow-up, no statistically significant differences between the groups were found. The operated legs were 18% weaker in leg press and 15% weaker in abduction than the unoperated legs, and the results were similar between groups. INTERPRETATION: The posterior and anterior approaches appeared to have the least negative effect on abduction and leg press muscular strength in the first postoperative week; the posterior approach had the least negative effect, even up to 6 weeks postoperatively. THA patients have reduced muscle strength in the operated leg (compared to the unoperated leg) 3 months after surgery.

Small and similar amounts of micromotion in an anatomical stem and a customized cementless femoral stem in regular-shaped femurs. A 5-year follow-up randomized RSA study.

BACKGROUND AND PURPOSE: High primary stability is important for long-term survival of uncemented femoral stems. Different stem designs are currently in use. The ABG-I is a well-documented anatomical stem with a press-fit design. The Unique stem is designed for a tight customized fit to the cortical bone of the upper femur. This implant was initially developed for patients with abnormal anatomy, but the concept can also be used in patients with normal femoral anatomy. We present 5-year radiostereometric analysis (RSA) results from a randomized study comparing the ABG-I anatomical stem with the Unique femoral stem. PATIENTS AND METHODS: 100 hips with regular upper femur anatomy were randomized to either the ABG-I stem or the Unique femoral stem. RSA measurements were performed postoperatively and after 3, 6, 12, 24, and 60 months. RESULTS: RSA measurements from 80 hips were available for analysis at the 5-year follow-up. Small amounts of movement were observed for both stems, with no statistically significant differences between the 2 types. INTERPRETATION: No improvement in long-term stability was found from using a customized stem design. However, no patients with abnormal geometry of the upper femur were included in this study.

The migration pattern of the Charnley femoral stem: a five-year follow-up RSA study in a well-functioning patient group.

BACKGROUND: Implant stability is considered vital to long-time implant survival in total hip arthroplasty (THA), since loose implants are reported to be a major cause of hip revision. There is an association between early implant micromotion and increased risk of revision. More implant-specific data are needed to establish acceptable levels of early implant movement. MATERIALS AND METHODS: Thirty-five patients (36 hips) undergoing Charnley THA were followed with repeated clinical, radiographic, and radiostereometric analysis (RSA) over 5 years. Twenty-three patients attended 5 years postoperatively. RESULTS: The patient group was well functioning based on the radiological and clinical evaluations. The stems constantly moved up to 5 years postoperatively, with subsidence, retroversion, and varus tilt, based on the RSA. CONCLUSION: Continuous movement of the Charnley stem was observed up to 5 years postoperatively in a well-functioning patient group. The migration data presented herein could be useful when defining acceptable migration limits for certain types of cemented femoral stems.

A randomized study on migration of the Spectron EF and the Charnley flanged 40 cemented femoral components using radiostereometric analysis at 2 years.

BACKGROUND AND PURPOSE: We performed a randomized study to determine the migration patterns of the Spectron EF femoral stem and to compare them with those of the Charnley stem, which is regarded by many as the gold standard for comparison of implants due to its extensive documentation. PATIENTS AND METHODS: 150 patients with a mean age of 70 years were randomized, single-blinded, to receive either a cemented Charnley flanged 40 monoblock, stainless steel, vaquasheen surface femoral stem with a 22.2-mm head (n = 30) or a cemented Spectron EF modular, matte, straight, collared, cobalt-chrome femoral stem with a 28-mm femoral head and a roughened proximal third of the stem (n = 120). The patients were followed with repeated radiostereometric analysis for 2 years to assess migration. RESULTS: At 2 years, stem retroversion was 2.3° and 0.7° (p < 0.001) and posterior translation was 0.44 mm and 0.17 mm (p = 0.002) for the Charnley group (n = 26) and the Spectron EF group (n = 74), respectively. Subsidence was 0.26 mm for the Charnley and 0.20 mm for the Spectron EF (p = 0.5). INTERPRETATION: The Spectron EF femoral stem was more stable than the Charnley flanged 40 stem in our study when evaluated at 2 years. In a report from the Norwegian arthroplasty register, the Spectron EF stem had a higher revision rate due to aseptic loosening beyond 5 years than the Charnley. Initial stability is not invariably related to good long-term results. Our results emphasize the importance of prospective long-term follow-up of prosthetic implants in clinical trials and national registries and a stepwise introduction of implants.

Wear and migration of highly cross-linked and conventional cemented polyethylene cups with cobalt chrome or Oxinium femoral heads: a randomized radiostereometric study of 150 patients.

This randomized study was performed to compare wear and migration of five different cemented total hip joint articulations in 150 patients. The patients received either a Charnley femoral stem with a 22.2 mm head or a Spectron EF femoral stem with a 28 mm head. The Charnley articulated with a γ-sterilized Charnley Ogee acetabular cup. The Spectron EF was used with either EtO-sterilized non-cross-linked polyethylene (Reflection All-Poly) or highly cross-linked (Reflection All-Poly XLPE) cups, combined with either cobalt chrome (CoCr) or Oxinium femoral heads. The patients were followed with repeated RSA measurements for 2 years. After 2 years, the EtO-sterilized non-cross-linked Reflection All-Poly cups had more than four times higher proximal penetration than its highly cross-linked counterpart. Use of Oxinium femoral heads did not affect penetration at 2 years compared to heads made of CoCr. Further follow-up is needed to evaluate the benefits, if any, of Oxinium femoral heads in the clinical setting. The Charnley Ogee was not outperformed by the more recently introduced implants in our study. We conclude that this prostheses still represents a standard against which new implants can be measured.

A prospective randomised radiostereometric analysis trial of SmartSet HV and Palacos R bone cements in primary total hip arthroplasty.

BACKGROUND: Introduction of new bone cements into clinical practice should include radiostereometric studies. MATERIALS AND METHODS: A prospective randomised radiostereometric study was performed, comparing SmartSet HV and Palacos R acrylic bone cements (without antibiotics) using third-generation cementing techniques in primary total hip arthroplasty. Thirty-five patients (36 hips) undergoing Charnley total hip arthroplasty were randomised to receive either of the two cements and were followed with repeated clinical, radiographic and radiostereometric examinations over 24 months. Twenty-seven patients (28 hips) attended 2 years postoperatively. RESULTS: The mean distal translation observed was -0.15 mm for SmartSet HV and -0.16 mm for Palacos R. The mean rotation around the longitudinal axis was 0.9 degrees for SmartSet HV and 1.2 degrees for Palacos R. The Merle d'Aubigne Postel score was the maximum of 18 points for all patients in both groups. CONCLUSIONS: No statistically significant difference in stem fixation with use of SmartSet HV and Palacos R was found at 2-year follow-up.