Western Ontario Osteoarthritis of the Shoulder Index (WOOS) - a validation for use in proximal humerus fractures treated with arthroplasty.

BACKGROUND: The Swedish shoulder and Arthroplasty Registry (SSAR) use the Western Ontario Osteoarthritis of the Shoulder Index (WOOS) as their shoulder-specific score in the follow-up. WOOS is not yet validated for use as the Patient Reported Outcome Measurement (PROM) for proximal humerus fractures (PHF) treated with shoulder hemiarthroplasty (SHA) in the Swedish registry. The aim of this study was to examine the validity, the reliability and the responsiveness of WOOS as a PROM for proximal humerus fractures treated with shoulder arthroplasty. METHODS: Data was collected from the SSAR from the 1st of January 2008 to the 31st of June 2011. A total of 72 subjects were identified with at least 1 year of follow-up. Of these 43 completed all the shoulder-specific PROM together with a clinical examination, including a WOOS retest and general health scores. A group of 29 did not undergo any clinical examination, but they completed all the questionnaires not requiring a clinical examination. The validity was assessed with WOOS compared to satisfaction level, and the Spearman rank coefficient was used for the correlation between WOOS and the shoulder-specific scores (Constant-Murley Score, Oxford Shoulder Score, American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form and EQ-5D. For reliability, Intra Class Correlation (ICC) was used for the test-retest assessment and Cronbach´s alpha for the construct reliability. RESULTS: The validity for WOOS had an excellent correlation (> 0.75) with all the shoulder-specific scores and a good correlation (> 0.6) with EQ-5D. The reliability with the test-retest of the total WOOS score and the subgroups had an excellent correlation. Cronbach´s alpha also supports the construct of WOOS. There were no floor or ceiling effects. CONCLUSIONS: We found that WOOS is a reliable tool for evaluating patients with SHA after PHF. Based on our study, we recommend the continued use of WOOS in shoulder arthroplasty registries and observational studies.

Primary hemiarthroplasty for the elderly patient with cognitive dysfunction and a displaced femoral neck fracture: a prospective, observational cohort study.

BACKGROUND: At least one-third of hip fracture patients have some degree of impaired cognitive status, which may complicate their postoperative rehabilitation. AIM: We aimed to describe the outcome for elderly patients with cognitive dysfunction operated with hemiarthroplasty (HA) for a femoral neck fracture and to study the impact postoperative geriatric rehabilitation has on functional outcome up to 1 year after surgery. METHODS: 98 patients with a displaced femoral neck fracture with a mean age of 86 years were included and followed up to 1 year. The outcomes were hip-related complications and reoperations, the capacity to return to previous walking ability, health-related quality of life, hip function and mortality. RESULTS: The prevalence of hip complications leading to a major reoperation was 6% and the 1-year mortality rate was 31%. The lack of geriatric rehabilitation was correlated with poorer outcomes overall and those who receive geriatric rehabilitation were less likely to be confined to a wheelchair or bedridden at the 1-year follow-up. CONCLUSIONS: Hemiarthroplasty is an acceptable option for elderly patients with a displaced femoral neck fracture and cognitive dysfunction. A lack of structured rehabilitation is associated with a significant deterioration in walking ability despite a well-functioning hip. However, the causality of this could be due to selection bias of healthier patients being sent to geriatric rehabilitation.

The influence of depression on patient-reported outcomes for hip-fracture patients 1 year after surgery: a prospective cohort study.

BACKGROUND: Depression is common in elderly hip-fracture patients and together with cognitive impairment is associated with increased risk of mortality. AIM: We aimed to examine the influence depression has on patient-reported outcome up to 1 year after acute hip fracture. METHODS: 162 hip-fracture patients participated in the prospective observational cohort study and were followed up at baseline, and 3 and 12 months using patient-reported outcome scores. Patients with cognitive impairment were excluded. Depression was defined as a score ≥ 8 on the depression subscale of the Hospital Anxiety Depression Scale (HADS D), having a diagnosis of depression or being treated with anti-depressant medication. Hip function was assessed using Harris Hip Score (HHS), EQ-5D was used to assess health status and Quality of life, and the Pain Numerical Rating Scale (PRNS) was used to assess pain levels. A linear regression model adjusted for group, age, sex, and ASA class was used to identify risk factors for functional outcome 12 months after fracture. RESULTS: 35 patients were included in the depression group versus 127 in the control group. No statistical differences were found in the demographic data (age, sex, ASA class, fracture type, operation method, living situation, activities of daily living ADL and clinical pathway) between the groups. In the regression model, we found no correlation between depression and the patient-reported outcome. CONCLUSION: In young elderly hip fracture patients without cognitive dysfunction, depression may not be of major importance for the rehabilitation of hip function in the short term.

HOPE-Trial: Hemiarthroplasty Compared with Total Hip Arthroplasty for Displaced Femoral Neck Fractures in Octogenarians: A Randomized Controlled Trial.

BACKGROUND: The choice of primary hemiarthroplasty or total hip arthroplasty in patients ≥80 years of age with a displaced femoral neck fracture has not been adequately studied. As the number of healthy, elderly patients ≥80 years of age is continually increasing, optimizing treatments for improving outcomes and reducing the need for secondary surgery is an important consideration. The aim of the present study was to compare the results of hemiarthroplasty with those of total hip arthroplasty in patients ≥80 years of age. METHODS: This prospective, randomized, single-blinded trial included 120 patients with a mean age of 86 years (range, 80 to 94 years) who had sustained an acute displaced femoral neck fracture <36 hours previously. The patients were randomized to treatment with hemiarthroplasty (n = 60) or total hip arthroplasty (n = 60). The primary end points were hip function and health-related quality of life at 2 years. Secondary end points included hip-related complications and reoperations, mortality, pain in the involved hip, activities of daily living, surgical time, blood loss, and general complications. The patients were reviewed at 3 months and 1 and 2 years. RESULTS: We found no differences between the groups in terms of hip function, health-related quality of life, hip-related complications and reoperations, activities of daily living, or pain in the involved hip. Hip function, activities of daily living, and pain in the involved hip deteriorated in both groups compared with pre-fracture values. The ability to regain previous walking function was similar in both groups. CONCLUSIONS: We found no difference in outcomes after treatment with either hemiarthroplasty or total hip arthroplasty in active octogenarians and nonagenarians with a displaced femoral neck fracture up to 2 years after surgery. Hemiarthroplasty is a suitable procedure in the short term for this group of patients. LEVEL OF EVIDENCE: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Artificial intelligence for analyzing orthopedic trauma radiographs.

Background and purpose - Recent advances in artificial intelligence (deep learning) have shown remarkable performance in classifying non-medical images, and the technology is believed to be the next technological revolution. So far it has never been applied in an orthopedic setting, and in this study we sought to determine the feasibility of using deep learning for skeletal radiographs. Methods - We extracted 256,000 wrist, hand, and ankle radiographs from Danderyd's Hospital and identified 4 classes: fracture, laterality, body part, and exam view. We then selected 5 openly available deep learning networks that were adapted for these images. The most accurate network was benchmarked against a gold standard for fractures. We furthermore compared the network's performance with 2 senior orthopedic surgeons who reviewed images at the same resolution as the network. Results - All networks exhibited an accuracy of at least 90% when identifying laterality, body part, and exam view. The final accuracy for fractures was estimated at 83% for the best performing network. The network performed similarly to senior orthopedic surgeons when presented with images at the same resolution as the network. The 2 reviewer Cohen's kappa under these conditions was 0.76. Interpretation - This study supports the use for orthopedic radiographs of artificial intelligence, which can perform at a human level. While current implementation lacks important features that surgeons require, e.g. risk of dislocation, classifications, measurements, and combining multiple exam views, these problems have technical solutions that are waiting to be implemented for orthopedics.

Comparison of metal ion concentrations and implant survival after total hip arthroplasty with metal-on-metal versus metal-on-polyethylene articulations.

Background and purpose - Large metal-on-metal (MoM) articulations are associated with metal wear and corrosion, leading to increased metal ion concentrations and unacceptable revision rates. There are few comparative studies of 28-mm MoM articulations with conventional metal-on-polyethylene (MoP) couplings. We present a long-term follow-up of a randomized controlled trial comparing MoM versus MoP 28-mm articulations, focused on metal ions and implant survival. Patients and methods - 85 patients with a mean age of 65 years at surgery were randomized to a MoM (Metasul) or a MoP (Protasul) bearing. After 16 years, 38 patients had died and 4 had undergone revision surgery. 13 patients were unavailable for clinical follow-up, leaving 30 patients (n = 14 MoM and n = 16 MoP) for analysis of metal ion concentrations and clinical outcome. Results - 15-year implant survival was similar in both groups (MoM 96% [95% CI 88-100] versus MoP 97% [95% CI 91-100]). The mean serum cobalt concentration was 4-fold higher in the MoM (1.5 µg/L) compared with the MoP cohort (0.4 µg/L, p < 0.001) and the mean chromium concentration was double in the MoM (2.2 µg/L) compared with the MoP cohort (1.0 µg/L, p = 0.05). Mean creatinine levels were similar in both groups (MoM 93 µmol/L versus MoP 92 µmol/L). Harris hip scores differed only marginally between the MoM and MoP cohorts. Interpretation - This is the longest follow-up of a randomized trial on 28-mm MoM articulations, and although implant survival in the 2 groups was similar, metal ion concentrations remained elevated in the MoM cohort even in the long term.

Waiting time to surgery is correlated with an increased risk of serious adverse events during hospital stay in patients with hip-fracture: A cohort study.

BACKGROUND: Hip fractures are common in the elderly and are associated with a high adverse event and mortality rate. Time to surgery is one of the major modifiable risk factors influencing adverse outcomes in hip-fracture patients. National guidelines and recommendations have been introduced which advocate specific time frames in which surgery should be performed i.e. within 24-48h. These time constraints have been arbitrarily set without being modelled on the linear assumption i.e. that risk increases continually over time and not within specific cut-off times. OBJECTIVES: To investigate how waiting time to surgery influenced the risk of serious adverse events in hip-fracture patients during the hospital stay and to examine how the risk increased over time. DESIGN: An observational single cohort study Participants 576 patients (72.4% females, mean [SD] age 82 [10]) years, with a hip fracture were included in the cohort study. METHODS: The outcomes of the study were the occurrence of serious adverse events during hospital stay, length of stay and one-year mortality. A structured medical record review was carried out to identify outcomes and mortality data was obtained from the Swedish National Death Registry. Waiting time to surgery was used as the exposure variable and age, sex, type of fracture, comorbidities using the American Society of Anaesthesiologists classification score and the presence of cognitive dysfunction were identified as confounders. A logistic regression analysis was performed to identify risk factors influencing outcomes. RESULTS: A total of 119 patients (20.6%) suffered 397 (range 1-5) serious adverse events during hospital stay. Every 10h of waiting time to surgery increased the risk of serious adverse events by 12% (odds ratio 1.12 [95% confidence interval 1.02-1.23]). We found no optimal cut-off times for waiting time to surgery. For every 24h of waiting time, the length of stay from surgery was increased by 0.6days (95% CI 0.1-1.1). We found no correlation between waiting time to surgery and one-year mortality. CONCLUSIONS: A large proportion of patients suffered from at least one serious adverse event after hip-fracture surgery and there are no safe limits for waiting time to surgery for hip-fracture patients. As the risk increases with every hour of waiting time, patients with higher American Society of Anesthesiologists classification scores, males and those with subtrochanteric fractures should be prioritized for surgery.

More complications with uncemented than cemented femoral stems in total hip replacement for displaced femoral neck fractures in the elderly.

Background and purpose - Total hip replacement (THR) is the preferred method for the active and lucid elderly patient with a displaced femoral neck fracture (FNF). Controversy still exists regarding the use of cemented or uncemented stems in these patients. We compared the effectiveness and safety between a modern cemented, and a modern uncemented hydroxyapatite-coated femoral stem in patients 65-79 years of age who were treated with THR for displaced FNF. Patients and methods - In a single-center, single-blinded randomized controlled trial, we included 69 patients, mean age 75 (65-79) and with a displaced FNF (Garden III-IV). 35 patients were randomized to a cemented THR and 34 to a reverse-hybrid THR with an uncemented stem. Primary endpoints were: prevalence of all hip-related complications and health-related quality of life, evaluated with EuroQol-5D (EQ-5D) index up to 2 years after surgery. Secondary outcomes included: overall mortality, general medical complications, and hip function. The patients were followed up at 3, 12, and 24 months. Results - According to the calculation of sample size, 140 patients would be required for the primary endpoints, but the study was stopped when only half of the sample size was included (n = 69). An interim analysis at that time showed that the total number of early hip-related complications was substantially higher in the uncemented group, 9 (among them, 3 dislocations and 4 periprosthetic fractures) as compared to 1 in the cemented group. The mortality and functional outcome scores were similar in the 2 groups. Interpretation - We do not recommend uncemented femoral stems for the treatment of elderly patients with displaced FNFs.

Proteasome inhibitor MG132 modulates inflammatory pain by central mechanisms in adjuvant arthritis.

AIMS: In rheumatoid arthritis (RA), pain and inflammation are initial symptoms followed by various degrees of bone and cartilage destruction. Previously, we have shown that reversible proteasome inhibitor MG132 attenuates pain and joint inflammation in a rat model of adjuvant-arthritis. Our present study aims to study the effects of MG132 on molecular changes in the dorsal root ganglia (DRG) and in the spinal cord (SC) using the same animal model. METHODS: Arthritis was induced by heat-killed Mycobacterium butyricum in rats. The expression of substance P (SP) was analyzed by quantitative reverse transcription polymerase chain reaction and immunohistochemistry in DRG and in the SC. The nuclear factor-κB (NF-κB) DNA-binding activity in the SC was analyzed by electromobility shift assay. RESULTS: Arthritic rats treated daily with MG132 demonstrated a marked reduction of SP gene expression in the DRG and number of SP-positive cells was reduced. In the spinal cord of arthritic rats elevated SP messenger RNA levels were normalized and NF-κB-DNA-binding activity was down-regulated in arthritic rats treated with MG132. CONCLUSION: Our results indicate that proteasome inhibitor MG132 attenuates pain in adjuvant arthritis by targeting the sensory neuropeptide substance P in the peripheral and central nervous systems. These effects may be mediated through the inhibition of NF-κB activation.

A validation of the Swedish version of the WORC index in the assessment of patients treated by surgery for subacromial disease including rotator cuff syndrome.

BACKGROUND: The Western Ontario Rotator Cuff Index (WORC) is a widely used instrument to measure quality of life in patients with subacromial pain or rotator cuff syndrome. The purpose of this study was to evaluate the psychometric properties of the Swedish version of the WORC for assessment of subacromial disease including rotator cuff syndrome treated by surgery. METHODS: A total of 65 patients were included in this study, mean age 60 years (range 36-82), 42% women, all were candidates for surgery for subacromial pain conditions at two orthopedic units during 2004-2006 and 2011-2012. Calculations of the validity of Pearson's correlation coefficient, floor and ceiling effects, reliability and responsiveness have formed the basis of assessment of the WORC index properties. WORC has been tested against Western Ontario Osteoarthritis of the Shoulder (WOOS), Oxford Shoulder Score and EQ-5D. An additional 49 patients, mean age 64 years (range 36-74) 20% of whom were women, were analyzed in a WORC test-retest with ICC and also correlated to Constant-Murley Score. RESULTS: The validity analysis of WORC showed high correlations with both the specific and the generic health measurement instrument. The reliability calculations of the WORC resulted in ICC = 0.97 and Cronbach's alpha = 0.97. Responsiveness was also excellent for WORC with Effect size = 1.35 and Standardized Response mean = 1.01. We found that the WORC showed a strong correlation with the WOOS (0.97) and the Constant-Murley Score (0.85). A good correlation was found with the Oxford Shoulder Score (0.74) and the EQ-5D (0.71). CONCLUSIONS: The Swedish version of WORC can be considered reliable, valid and responsive for use as an assessment of outcome and a health measurement instrument for patients treated by surgery for subacromial disease including rotator cuff syndrome.

Increased Long-Term Cardiovascular Risk After Total Hip Arthroplasty: A Nationwide Cohort Study.

Total hip arthroplasty is a common and important treatment for osteoarthritis patients. Long-term cardiovascular effects elicited by osteoarthritis or the implant itself remain unknown. The purpose of the present study was to determine if there is an increased risk of late cardiovascular mortality and morbidity after total hip arthroplasty surgery.A nationwide matched cohort study with data on 91,527 osteoarthritis patients operated on, obtained from the Swedish Hip Arthroplasty Register. A control cohort (n = 270,688) from the general Swedish population was matched 1:3 to each case by sex, age, and residence. Mean follow-up time was 10 years (range, 7-21).The exposure was presence of a hip replacement for more than 5 years. The primary outcome was cardiovascular mortality after 5 years. Secondary outcomes were total mortality and re-admissions due to cardiovascular events.During the first 5 to 9 years, the arthroplasty cohort had a lower cardiovascular mortality risk compared with the control cohort. However, the risk in the arthroplasty cohort increased over time and was higher than in controls after 8.8 years (95% confidence interval [CI] 7.0-10.5). Between 9 and 13 years postoperatively, the hazard ratio was 1.11 (95% CI 1.05-1.17). Arthroplasty patients were also more frequently admitted to hospital for cardiovascular reasons compared with controls, with a rate ratio of 1.08 (95% CI 1.06-1.11).Patients with surgically treated osteoarthritis of the hip have an increased risk of cardiovascular morbidity and mortality many years after the operation when compared with controls.

Similar results comparing early and late surgery in open repair of traumatic rotator cuff tears.

PURPOSE: The purpose was to investigate whether surgical repair earlier or later than 3 months after injury may result in similar outcomes and patient satisfaction. METHODS: Seventy-three patients (75 shoulders, 58 males, mean age 59) who had undergone surgical intervention for traumatic rotator cuff tears from 1999 to 2011 were assessed by MRI, clinical examination and Western Ontario Rotator Cuff Index (WORC) as a primary outcome measure and Oxford Shoulder score (OSS), Constant-Murley score (CS) and EQ-5D as secondary. The patients treated less than 3 months after injury (n = 39) were compared with patients treated more than 3 months after injury (n = 36). The average follow-up time was 56 months (range 14-149), and the average time from injury to repair for all patients was 16 weeks (range 3-104). A single senior radiologist performed a blinded evaluation of all the MRIs. Rotator cuff integrity, presence of arthritis, fatty degeneration and muscle atrophy were evaluated. RESULTS: No differences were found for any of the assessed outcomes (WORC, OSS, CS and EQ-5D) between the two groups. The mean WORC % was 77 % for both groups. Re-tear frequency was 24 %, nine in both groups. Patients with re-tear reported less satisfaction with their outcome. CONCLUSIONS: The surgical treatment of symptomatic traumatic rotator cuff tears repairable later than 3 months after injury yields a good functional outcome, a high level of subjective patient satisfaction, and at the same level for patients receiving earlier treatment. Based on our findings, surgical repair could be encouraged whenever technically possible. LEVEL OF EVIDENCE: Retrospective Comparative Study, Level III.

Loss of offset after pertrochanteric hip fractures affects hip function one year after surgery with a short intramedullary nail. A prospective cohort study.

PURPOSE: We hypothesised that protruding collum screws in intramedullary nails used for pertrochanteric fractures cause lateral pain/discomfort and that loss of offset relates to poorer hip function. METHODS: Seventy-six patients with an acute pertrochanteric femoral fracture AO types A1 and A2 were operated upon using a short intramedullary nail and were included in a prospective observational cohort study and followed-up for one year. The main outcome variables were lateral pain and hip function as evaluated with the Harris Hip Score. The main exposure was compression along the collum screw and lateral protrusion measured by anteroposterior X-ray images. Perioperative images were compared to images at the follow-up visit. Outcome variables were adjusted in regression models for reduction, fracture type, body mass index, sex and age. RESULTS: A total of 28 (36 %) patients experienced lateral pain at one year. We found a correlation between lateral protrusion and lateral pain, adjusted OR 4.5 per protruding centimetre (95 % CI, 1.1-17.5). Collum compression correlated with a poorer outcome with Harris Hip Score -14.2 per compressed centimetre (95 % CI, -21.8 to -6.7). CONCLUSIONS: In patients with type A1 and A2 pertrochanteric fractures operated on using intramedullary nailing, a large compression and lateral protrusion of the collum screw are associated with poorer hip function and lateral pain. New technical improvements for implants should focus on these factors to improve functional outcome after surgery.

Lower periprosthetic bone loss and good fixation of an ultra-short stem compared to a conventional stem in uncemented total hip arthroplasty.

BACKGROUND AND PURPOSE: We hypothesized that an ultra-short stem would load the proximal femur in a more physiological way and could therefore reduce the adaptive periprosthetic bone loss known as stress shielding. PATIENTS AND METHODS: 51 patients with primary hip osteoarthritis were randomized to total hip arthroplasty (THA) with either an ultra-short stem or a conventional tapered stem. The primary endpoint was change in periprosthetic bone mineral density (BMD), measured with dual-energy x-ray absorptiometry (DXA), in Gruen zones 1 and 7, two years after surgery. Secondary endpoints were change in periprosthetic BMD in the entire periprosthetic region, i.e. Gruen zones 1 through 7, stem migration measured with radiostereometric analysis (RSA), and function measured with self-administered functional scores. RESULTS: The periprosthetic decrease in BMD was statistically significantly lower with the ultra-short stem. In Gruen zone 1, the mean difference was 18% (95% CI: -27% to -10%). In zone 7, the difference was 5% (CI: -12% to -3%) and for Gruen zones 1-7 the difference was also 5% (CI: -9% to -2%). During the first 6 weeks postoperatively, the ultra-short stems migrated 0.77 mm more on average than the conventional stems. 3 months after surgery, no further migration was seen. The functional scores improved during the study and were similar in the 2 groups. INTERPRETATION: Up to 2 years after total hip arthroplasty, compared to the conventional tapered stem the ultra-short uncemented anatomical stem induced lower periprosthetic bone loss and had equally excellent stem fixation and clinical outcome.

Variability of platelet aggregation in patients with clopidogrel treatment and hip fracture: A retrospective case-control study on 112 patients.

AIM: To identify the rate of non-responders to clopidogrel treatment in hip fracture patients and study how non-responders differ from controls. METHODS: In a retrospective case-control study we included 28 cases of acute proximal femoral fracture with clopidogrel treatment 2011 to 2013. Eighty-four controls from the same time period were included. Data collected included response to clopidogrel measured with multiple electrode aggregometry (MEA), intraoperative bleeding, erythrocyte transfusion, time to surgery and the incidence of adverse events up to 3 mo after surgery. RESULTS: Eight (29%) of the 28 cases were non-responders. The median intraoperative bleeding was 300 mL (range, 0-1500), and was lower for non-responders (50 mL) but did not reach statistical significance. Erythrocyte transfusions did not differ between responders, non-responders and controls. Forty-five (40%) of 112 patients had adverse events postoperatively but the rate did not differ between patients with and without clopidogrel treatment. CONCLUSION: Almost one-third of patients with clopidogrel treatment and an acute proximal femoral fracture are non-responders to antiplatelet therapy and can be operated without delay.

No effect of risedronate on femoral periprosthetic bone loss following total hip arthroplasty. A 4-year follow-up of 61 patients in a double-blind, randomized placebo-controlled trial.

BACKGROUND AND PURPOSE: We have previously shown that during the first 2 years after total hip arthroplasty (THA), periprosthetic bone resorption can be prevented by 6 months of risedronate therapy. This follow-up study investigated this effect at 4 years. PATIENTS AND METHODS: A single-center, double-blind, randomized placebo-controlled trial was carried out from 2006 to 2010 in 73 patients with osteoarthritis of the hip who were scheduled to undergo THA. The patients were randomly assigned to receive either 35 mg risedronate or placebo orally, once a week, for 6 months postoperatively. The primary outcome was the percentage change in bone mineral density (BMD) in Gruen zones 1 and 7 in the proximal part of the femur at follow-up. Secondary outcomes included migration of the femoral stem and clinical outcome scores. RESULTS: 61 of the 73 patients participated in this 4-year (3.9- to 4.1-year) follow-up study. BMD was similar in the risedronate group (n = 30) and the placebo group (n = 31). The mean difference was -1.8% in zone 1 and 0.5% in zone 7. Migration of the femoral stem, the clinical outcome, and the frequency of adverse events were similar in the 2 groups. INTERPRETATION: Although risedronate prevents periprosthetic bone loss postoperatively, a decrease in periprosthetic BMD accelerates when therapy is discontinued, and no effect is seen at 4 years. We do not recommend the use of risedronate following THA for osteoarthritis of the hip.

Larger femoral periprosthetic bone mineral density decrease following total hip arthroplasty for femoral neck fracture than for osteoarthritis: a prospective, observational cohort study.

Studies on patients with degenerative joint disease of the hip show that femoral periprosthetic bone mineral decreases following total hip arthroplasty. Scarcely any osteodensitometric data exist on femoral neck fracture (FNF) patients and periprosthetic bone remodelling. In two parallel cohorts we enrolled 87 patients (mean age, 72 ± 12 years; male:female ratio, 30:57) undergoing total hip arthroplasty for either primary osteoarthritis (OA) of the hip (n = 37) or for an acute FNF (n = 50) and followed them for a mean of 5.4 years. Outcomes were bone mineral density (BMD) changes in the periprosthetic Gruen zones 1-7, the incidence of periprosthetic fractures and clinical outcome. The bone mineral loss in the fracture group was more than twice that of the osteoarthritis group, -16.9% versus -6.8% (p = 0.004). The incidence of periprosthetic fractures was 12% (6/50) in the fracture cohort compared with none (0%) in the OA cohort (p = 0.03). Periprosthetic bone mineral loss following total hip arthroplasty is significantly greater in patients who are treated for acute FNF than in OA patients. This decrease of BMD follows a different pattern with the FNF patients losing larger proportions of bone in Gruen zones 1, 2, 6, and 7 while the OA patients tend to have larger losses only in zones 1 and 7.

Vitamin-E diffused highly cross-linked polyethylene liner compared to standard liners in total hip arthroplasty. A randomized, controlled trial.

PURPOSE: We hypothesized that a vitamin E-treated polyethylene articulating liner had lower femoral head penetration than a conventional liner. METHODS: Fifty-one patients with primary hip osteoarthritis were randomized to an uncemented cup with either vitamin E-treated highly cross-linked polyethylene (HXLPE) (vitamin-e group, n = 25) or a standard HXLPE liner (control group, n = 26) and followed for two years after surgery. The outcome variable was polyethylene (PE) linear head penetration, measured with radiostereometry (RSA). RESULTS: The head penetration in x- (medial/lateral) and y- (vertical) axes was significantly lower for the vitamin E-treated liner up to two years with a mean difference between the groups of 0.10 mm (95 % CI 0.04-0.18) and 0.08 mm (95 % CI 0.01-0.15), respectively. The initial total penetration was lower for the vitamin-E group but did not reach statistical significance at two years with a mean difference between the groups of 0.07 mm (95 % CI -0.001 to 0.15, p = 0.09). We found no differences in clinical outcome between the groups. CONCLUSIONS: In this prospective, randomized, controlled trial on a new vitamin-E diffused HXLPE liner we found, compared to a conventional HXLPE liner, lower initial head penetration and lower superior and medial wear. A longer follow-up than two years is necessary to demonstrate lower overall head penetration in vitamin-E liners compared to contemporary highly cross-linked PE.

Porous titanium construct cup compared to porous coated titanium cup in total hip arthroplasty. A randomised controlled trial.

PURPOSE: The purpose of this study was to determine if a new titanium cup with increased porosity resulted in different periacetabular bone loss and migration compared to a porous coated cup. METHODS: Fifty-one patients with primary hip osteoarthritis were randomized to either a cup with porous titanium construct backside (porous titanium group, n = 25) or a conventional porous coated titanium cup (control group, n = 26). The primary outcome variable was change in periacetabular bone mineral density two years after surgery measured with dual energy X-ray absorptiometry (DXA). Secondary outcomes were implant fixation measured with radiostereometry (RSA) and clinical outcome scores. RESULTS: The pattern of bone remodelling was similar in the two groups with almost complete restoration to baseline values. BMD diminished in the two proximal zones and increased in the two distal zones. After minimal migration up to six months all implants in both groups became stable. We found no difference between the two groups in clinical outcome scores. CONCLUSIONS: In this prospective, randomized, controlled trial on a new porous titanium cup we found, compared to the control group, no clinically relevant differences regarding periacetabular bone preservation, implant fixation or clinical outcome up to two years postoperatively.

Unstable hip arthroplasties. A prospective cohort study on seventy dislocating hips followed up for four years.

PURPOSE: Dislocating hip prosthesis remains a substantial clinical problem. The aim of this study is to describe the risk of recurrent instability after a primary dislocation of primary hip arthroplasty performed for osteoarthritis (OA) or femoral neck fracture (FNF). METHODS: Seventy patients (male/females: 25/45; mean age 77 [range 46-94]) with dislocating hip arthroplasties were included in a prospective cohort study and followed for four years. Radiographs and all surgical records were reviewed. We compared stable hips to those who either continued to dislocate or were revised due to recurrent instability (unstable group). RESULTS: Forty-two hips (60 %) had episodes of recurrent instability leading to repeated closed reductions or major revision surgery and were classified as unstable. A diagnosis of FNF and cognitive dysfunction (OR 9.3 [95 % CI 1.4-64.1]) or postoperative radiological discrepancies such as leg-lengthening and offset reduction increased the risk of further instability (OR 13.5 [95 % CI 1.3-148.1]). The surgical approach at primary surgery and ASA class did not significantly influence the risk of continued instability. CONCLUSIONS: Patients with a FNF and cognitive dysfunction or with sub-optimal postoperative radiographs after hip arthroplasty surgery are at high risk of recurrent instability after a primary dislocation. For hip fracture patients, all efforts should be made to avoid the first dislocation.