Background and purpose
The increased use of patient-reported outcomes (PROs) in orthopedics requires data on estimated minimal clinically important improvements (MCIIs) and patient-acceptable symptom states (PASSs). We wanted to find cut-points corresponding to minimal clinically important PRO change score and the acceptable postoperative PRO score, by estimating MCII and PASS 1 year after total hip arthroplasty (THA) for the Hip Dysfunction and Osteoarthritis Outcome Score (HOOS) and the EQ-5D.
Patients and methods
THA patients from 16 different departments received 2 PROs and additional questions preoperatively and 1 year postoperatively. The PROs included were the HOOS subscales pain (HOOS Pain), physical function short form (HOOS-PS), and hip-related quality of life (HOOS QoL), and the EQ-5D. MCII and PASS were estimated using multiple anchor-based approaches.
Of 1,837 patients available, 1,335 answered the preoperative PROs, and 1,288 of them answered the 1-year follow-up. The MCIIs and PASSs were estimated to be: 24 and 91 (HOOS Pain), 23 and 88 (HOOS-PS), 17 and 83 (HOOS QoL), 0.31 and 0.92 (EQ-5D Index), and 23 and 85 (EQ-VAS), respectively. MCIIs corresponded to a 38–55% improvement from mean baseline PRO score and PASSs corresponded to absolute follow-up scores of 57–91% of the maximum score in THA patients 1 year after surgery.
This study improves the interpretability of PRO scores. The different estimation approaches presented may serve as a guide for future MCII and PASS estimations in other contexts. The cutoff points may serve as reference values in registry settings.
The Oxford hip score (OHS) is a 12-item questionnaire designed
and developed to assess function and pain from the perspective of
patients who are undergoing total hip replacement (THR). The OHS
has been shown to be consistent, reliable, valid and sensitive to
clinical change following THR. It has been translated into different
languages, but no adequately translated, adapted and validated Danish
language version exists.
The OHS was translated and cross-culturally adapted into Danish
from the original English version, using methods based on best-practice
guidelines. The translation was tested for psychometric quality
in patients drawn from a cohort from the Danish Hip Arthroplasty
The Danish OHS had a response rate of 87.4%, no floor effect
and a 19.9% ceiling effect (as expected in post-operative patients).
Only 1.2% of patients had too many items missing to calculate a
sum score. Construct validity was adequate and 80% of our predefined
hypotheses regarding the correlation between scores on the Danish
OHS and the other questionnaires were confirmed. The intraclass
correlation (ICC) of the different items ranged from 0.80 to 0.95
and the average limits of agreement (LOA) ranged from -0.05 to 0.06.
The Danish OHS had a high internal consistency with a Cronbach’s
alpha of 0.99 and an average inter-item correlation of 0.88.
This Danish version of the OHS is a valid and reliable patient-reported
outcome measurement instrument (PROM) with similar qualities to
the original English language version.
Patient-reported outcome measurement instrument; PRO; PROMs; Oxford hip score; OHS; Validation; Total hip replacement; THR; Danish Hip Arthroplasty Registry (DHR)
Background and purpose
A questionnaire was introduced by the New Zealand Arthroplasty Registry for use when evaluating the outcome of total ankle replacement surgery. We evaluated the reliability, validity, and responsiveness of the modified Swedish version of the questionnaire (SEFAS) in patients with osteoarthritis or inflammatory arthritis before and/or after their ankle was replaced or fused.
Patients and methods
The questionnaire was translated into Swedish and cross-culturally adapted according to a standardized procedure. It was sent to 135 patients with ankle arthritis who were scheduled for or had undergone surgery, together with the foot and ankle outcome score (FAOS), the short form 36 (SF-36) score, and the EuroQol (EQ-5D) score. Construct validity was evaluated with Spearman’s correlation coefficient when comparing SEFAS with FAOS, SF-36, and EQ-5D, content validity by calculating floor and ceiling effects, test-retest reliability with intraclass correlation coefficient (ICC), internal consistency with Cronbach’s alpha (n = 62), agreement by Bland-Altman plot, and responsiveness by effect size and standardized response mean (n = 37).
For construct validity, we correlated SEFAS with the other scores and 70% or more of our predefined hypotheses concerning correlations could be confirmed. There were no floor or ceiling effects. ICC was 0.92 (CI 95%: 0.88–0.95), Cronbach’s alpha 0.96, effect size was 1.44, and the standardized response mean was 1.00.
SEFAS is a self-reported foot and ankle score with good validity, reliability and responsiveness, indicating that the score can be used to evaluate patients with osteoarthritis or inflammatory arthritis of the ankle and outcome of surgery.
The aim of the study was to evaluate if physical functions usually associated with a younger population were of importance for an older population, and to construct an outcome measure for hip osteoarthritis with improved responsiveness compared to the Western Ontario McMaster osteoarthritis score (WOMAC LK 3.0).
A 40 item questionnaire (hip disability and osteoarthritis outcome score, HOOS) was constructed to assess patient-relevant outcomes in five separate subscales (pain, symptoms, activity of daily living, sport and recreation function and hip related quality of life). The HOOS contains all WOMAC LK 3.0 questions in unchanged form. The HOOS was distributed to 90 patients with primary hip osteoarthritis (mean age 71.5, range 49–85, 41 females) assigned for total hip replacement for osteoarthritis preoperatively and at six months follow-up.
The HOOS met set criteria of validity and responsiveness. It was more responsive than WOMAC regarding the subscales pain (SRM 2.11 vs. 1.83) and other symptoms (SRM 1.83 vs. 1.28). The responsiveness (SRM) for the two added subscales sport and recreation and quality of life were 1.29 and 1.65, respectively. Patients ≤ 66 years of age (range 49–66) reported higher responsiveness in all five subscales than patients >66 years of age (range 67–85) (Pain SRM 2.60 vs. 1.97, other symptoms SRM 3.0 vs. 1.60, activity of daily living SRM 2.51 vs. 1.52, sport and recreation function SRM 1.53 vs. 1.21 and hip related quality of life SRM 1.95 vs. 1.57).
The HOOS 2.0 appears to be useful for the evaluation of patient-relevant outcome after THR and is more responsive than the WOMAC LK 3.0. The added subscales sport and recreation function and hip related quality of life were highly responsive for this group of patients, with the responsiveness being highest for those younger than 66.
Expectations of higher activity levels associated with hip resurfacing arthroplasty (HRA) may be driving better outcomes in this group compared to total hip arthroplasty (THA). Previous studies evaluated expectations before consulting with the surgeon, although these expectations are likely unrealistic and would change after the consultation. We compared HRA and THA patient expectation after consultation with the surgeon.
In a prospective registry setting, patients awaiting HRA were matched to THA patients on age, sex, and preoperative Lower Extremity Activity Scale score (range 1–18, 18 highest activity level). Patients completed a validated 18-item expectations survey preoperatively. Mean overall expectations scores were first compared. Exploratory factor analysis (EFA) was then performed to determine if grouping of individual expectations items represented meaningfully different underlying factors in the 2 groups.
We matched 123 pairs. Mean expectation scores were similar (HRA: 85.2±15.5, THA: 87.3±13.9; p-value=0.249). EFA showed that HRA and THA patients shared in common expectations of 1) pain relief and improvement in daily activities (9 items) and 2) eliminating pain medications, the need for cane and improving sexual activity (3 items). THA patients perceived the remaining 6 items as an overall third expectation of participation in higher-level activities. However, HRA patients perceived a fourth expectation of normal range of motion (2 items) independent of the other higher-level activities (4 items).
Even after consulting with a surgeon, patients’ expectations differed between HRA and THA patients regarding higher-level activities. More counseling of patients seeking hip arthroplasty is thus needed.
Return to sport is a key patient demand after hip arthroplasty and some patients are even involved in high-impact sports. Although polyethylene wear is related to the number of cycles and the importance of the load, it is unclear whether high-impact sport per se influences THA durability.
Therefore, we compared (1) function between the patients involved in high-impact sports and the patients with lower activities as measured by the Harris hip score (HHS) and the Hip Osteoarthritis Outcome Score (HOOS); (2) linear wear rates; and (3) survivorships considering revision for mechanical failure with radiographic signs of aseptic loosening as the end point.
We retrospectively identified 70 patients who engaged in high-impact sports and 140 with low activity levels from among 843 THAs from a prospectively collected database performed between September 1, 1995, and December 31, 2000. Patients were evaluated at a minimum followup of 10 years (mean, 11 years; range, 10–15 years) by two independent observers. We obtained a HHS and HOOS at each followup.
The mean HOOS was higher in the high-impact group for three of the five subscales of the HOOS. Mean linear wear was higher in the high-impact group than in the low-activities group. We also found a higher number of revisions in the high-activity group.
Our observations confirm concern about the risk of THA mechanical failures related to high-impact sport, and patient and surgeons alike should be aware of these risks of mechanical failures.
Level of Evidence
Level III, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.
Despite the common prevalence of lumbar spine and degenerative hip disorders, there are few descriptions of patients with coexisting hip and lumbar spine disorders. The independent economic burden of each disorder is substantial but the financial burden when the disorders are coexisting is unknown.
The purpose of this study is to determine the prevalence of coexisting hip and lumbar spine disorders (LSD) in a large cohort of patients with hip osteoarthritis treated with total hip arthroplasty (THA) and determine the impact on pain and functional THA outcomes and physician charges.
This is a retrospective study performed at a tertiary university.
3206 patients who underwent total hip replacement from 1996-2008.
Self-report measures: Visual Analog Scale. Functional measures: modified Harris Hip Score (mHHS), UCLA hip questionnaire. Economic impact measures: physician medical charges.
International Classification of Diseases (ICD-9) billing codes related to LSDs were cross referenced with the 3206 patients who had undergone a THA to determine which patients were also evaluated by a spine specialist. Demographic, hip clinical outcomes and physician charges for patients with THA alone (THA alone) were compared to patients treated with THA and diagnosed with a LSD (THA + LSD).
Of 3206 patients who underwent THA, 566 (18%) were also evaluated by a spine specialist. Of those with a LSD, 334 (59%) were women with an older average age (64.5+13.3yrs) compared to patients treated with THA alone (51%, 58.5+15.5 yrs, P=0.0001). Patients in the THA alone group as compared to the THA+ LSD group had greater improvement in the mHHS (P =0.0001), UCLA score (P =0.0001) and pain (P=0.0001). Patients in the THA+LSD group incurred on average $2,668 more in charges per episode of care as compared to patients in the THA alone group. (P<0.001) Patients in the THA+LSD group had more days per episode of care (P=0.001).
Patients undergoing THA alone had greater improvement in function and pain relief with fewer medical charges as compared to patients undergoing a THA and treatment for a LSD. The prevalence of coexisting hip and spine disorders is likely higher than currently documented. Further study is needed in order to improve therapeutic recommendations and determine the potential for reduction in medical expenses associated with concurrent treatment of hip osteoarthritis and lumbar spine disorders.
hip; arthroplasty; lumbar spine; low back pain; osteoarthritis; hip-spine syndrome
There is currently no German version of the Oxford hip score. Therefore we sought to cross-culturally adapt and validate the Oxford hip score for use with German-speaking patients (OHS-D) with osteoarthritis of the hip using a forward-backward translation procedure. We then assessed the new score in 105 consecutive patients (mean age, 63.4 years; 48 women) undergoing THA. We specifically determined: the number of fully completed questionnaires, reliability, concurrent validity by correlation with the WOMAC, Harris hip score, and SF-12, and distribution of floor and ceiling effects. We received 96.6% fully completed questionnaires. An intraclass correlation coefficient of 0.90 and Cronbach’s alpha of 0.87 suggested the OHS-D was reliable. Correlation coefficients between the OHS-D and the WOMAC total score, pain subscale, stiffness subscale, and physical function subscale were 0.82, 0.70, 0.68, and 0.82, respectively. OHS-D correlated with the Harris hip score (r = 0.63) and the physical component scale of the SF-12 (r = 0.58). We observed no ceiling or floor effects. The OHS-D appeared a reliable and valid measurement tool for assessing pain and disability with German-speaking patients with hip osteoarthritis.
Level of Evidence: Level I, diagnostic study. See the Guidelines for Authors for a complete description of levels of evidence.
Total hip arthroplasty (THA) is a commonly performed procedure with increasing frequency in the young adult. While most available outcome measures can document postoperative improvement in pain and function, they do not measure the ability to perform high-demand activities.
We present and validate a user-friendly discriminating hip scoring system (the functional hip score) for use in younger, “high-demand” patients undergoing hip arthroplasty surgery.
We studied 38 subjects without any hip symptoms and 72 patients undergoing THA for osteoarthritis of the hip. Preprocedure and postprocedure scores were collected in the latter cohort of patients. SF-36 and WOMAC scores were used to validate our functional scoring system. The functional hip score was tested for internal consistency, reliability, and criterion validity.
The functional hip score had high test–retest reliability, internal consistency, and criterion validity. This can be used to measure functional outcome in the younger high-demand adult patient undergoing THA.
Our discriminating functional hip score can reliably measure improvement in hip function in the younger high-demand adult. Current scoring systems have ceiling effects and are unable to differentiate a high performing hip replacement from the routine hip replacement. The use of functional tasks that are measured objectively allows better documentation of improvement in hip function.
outcomes; functional scores; hip outcomes; young adult hip
Primary total hip arthroplasty (THA) is an effective treatment for hip osteoarthritis, assessed by whatever distribution-based measures of responsiveness. Yet, the group level evaluation has provided very little evidence contributes to our understanding of the large variation of treatment outcome. The objective is to develop criteria that classify individual treatment health related quality of life (HRQOL) outcome after primary THA, adjusted by preoperative scores.
We prospectively measured 147 patients' disease specific HRQOL on the date of consultation and 12 months post operation by Western Ontario McMaster Universities Osteoarthritis Index (WOMAC). Regression models were used to determine the "expected" outcome for a certain individual baseline score. The ceiling effect of WOMAC measurement is addressed by implementing a left-censoring method.
The classification criteria are chosen to be the lower boundary of the 95% confidence interval (CI) of the estimated median from the regression. The robustness of the classification criteria was demonstrated using the Monte-Carlo simulation.
The classification criteria are robust and can be applied in general orthopaedic research when the sample size is reasonable large (over 500).
There is no current consensus on the most appropriate prosthesis for treating symptomatic osteoarthritis (OA) of the hip in young, active patients. Modern metal on metal hip resurfacing arthroplasty (HR) has gained popularity as it is theoretically more stable, bone conserving and easier to revise than total hip arthroplasty. Early results of metal on metal resurfacing have been encouraging. We have compared two well matched cohorts of patients with regard to function, pain relief and patient satisfaction.
This prospective study compares 2 cohorts of young, active patients treated with hip resurfacing (137 patients, 141 hips) and custom uncemented (CADCAM) stems (134 patients, 141 hips). All procedures were performed by a single surgeon. Outcome measures included Oxford, WOMAC and Harris hip scores as well as an activity score. Statistical analysis was performed using the unpaired student's t-test.
One hundred and thirty four and 137 patients were included in the hip replacement and resurfacing groups respectively. The mean age of these patients was 54.6 years. The mean duration of follow up for the hip resurfacing group was 19.2 months compared to 13.4 months for the total hip replacement group.
Pre operative oxford, Harris and WOMAC scores in the THA group were 41.1, 46.4 and 50.9 respectively while the post operative scores were 14.8, 95.8 and 5.0. In the HR group, pre- operative scores were 37.0, 54.1 and 45.9 respectively compared to 15.0, 96.8 and 6.1 post operatively. The degree of improvement was similar in both groups.
There was no significant clinical difference between the patients treated with hip resurfacing and total hip arthroplasty in the short term.
Little is known about the impact of the reason for revision total hip arthroplasty (THA) on the outcomes following revision THA. In this study, our objective was to assess the association of operative diagnosis with patient-reported outcomes (PROs) after revision THA.
We used prospectively collected data from the Mayo Clinic Total Joint Registry that collects pre- and post-operative pain and function outcomes using a validated Hip questionnaire, on all revision THAs from 1993–2005. We used logistic regression to assess the odds of moderate-severe index hip pain and moderate-severe limitation in activities of daily living (ADLs) 2- and 5-years after revision THA. We calculated odds ratios (OR) and 95% confidence intervals (CIs).
For the 2- and 5-year cohorts, the operative diagnosis was loosening/wear/osteolysis in 73% and 75%; dislocation/bone or prosthesis fracture/instability or non-union in 17% and 15%; and failed prior arthroplasty with components removed/infection in 11% and 11%, respectively. In multivariable-adjusted analyses that included preoperative ADL limitations, compared to patients with loosening/wear/osteolysis, patients with dislocation/fracture/instability/non-union had OR of 2.2 (95% CI, 1.3-3.5; p = 0.002) for overall moderate-severe ADL limitation and those with failed prior arthroplasty/infection had OR of 1.6 (95% CI, 1.0-2.8; p = 0.06). At 5-years, ORs were lower and differences were no longer significant. Moderate-severe pain did not differ significantly by diagnosis, at 2- or 5-years in multivariable adjusted analyses, with one exception, i.e. failed prior arthroplasty/infection had a trend towards significance with odds ratio of 1.9 (95% CI, 0.9-3.8; p = 0.07).
Operative diagnosis is independently associated with ADL limitations, but not pain, at 2-years after revision THA. Patients should be informed of the risk of poorer short-term outcomes based on their diagnosis.
Total hip replacement; Arthroplasty; Joint replacement; Patient-reported outcomes; Diagnosis
Background and purpose
There has been a limited amount of research on survival of total hip arthroplasties (THAs) in rheumatoid arthritis (RA). We therefore performed a population-based, nationwide study to compare the survival of primary THAs in RA patients and in osteoarthritis (OA) patients. We also wanted to identify predictors of THA failure in RA patients.
Using the Danish Hip Arthroplasty Registry, we identified 1,661 primary THAs in RA patients and 64,858 in OA patients, all of which were inserted between 1995 and 2008. The follow-up period was up to 14 years for both groups.
Regarding overall THA survival, the adjusted RR for RA patients compared to OA patients was 0.81 (95% CI: 0.65–1.01). We found no difference in survival of cups between primary THAs in RA and OA patients. In contrast, there was better overall survival of stems in RA patients than in OA patients, both regarding revision due to aseptic loosening (adjusted RR = 0.58; 95% CI: 0.34–0.99) and for any reason (adjusted RR = 0.63; 95% CI: 0.45–0.88). In RA patients, males had a higher risk of revision than females concerning aseptic loosening of the stem, any revision of the stem, and any revision of both components.
The overall survival of primary THAs in RA patients is similar to THA survival in OA patients. Stem survival appeared to be better in RA patients, while survival of the total THA concept did not show any statistically significant differences between the two groups. In RA patients, males appear to have a greater risk of revision than females.
International guidelines recommend thrombosis prophylaxis after total hip arthroplasty (THA) and total knee arthroplasty (TKA) for up to 35 days. However, previous studies often have hospital stays (length of stay; LOS) of 8–12 days and not considering early mobilisation, which may reduce incidence of venous thromboembolic events (VTE). We investigated the incidence of any symptomatic thromboembolic events (TEEs) with only in-hospital prophylaxis if LOS ≤5 days after fast-track THA and TKA.
A prospective descriptive multicentre cohort study in fast-track THA and TKA from February 2010 to December 2011, with complete 90-day follow-up through the Danish National Patient Registry and patient files.
6 Danish high-volume centres with a similar standardised fast-track setup, including spinal anaesthesia, opioid-sparing analgesia, early mobilisation, functional discharge criteria and discharge to own home.
4924 consecutive unselected unilateral primary THA and TKAs in patients ≥18 years with no preoperative use of continuous ‘potent’ anticoagulative therapy (vitamin K antagonists).
Prophylaxis with low-molecular-weight heparin or factor Xa-inhibitors only during hospitalisation when LOS ≤5 days.
Incidence of symptomatic TEE-related, VTE-related and VTE-related mortality ≤90 days postoperatively.
LOS ≤5 days and thromboprophylaxis only during hospitalisation occurred in 4659 procedures (94.6% of total). Median LOS and prophylaxis duration was 2 days (IQR 2–3) with 0.84% (95% CI 0.62% to 1.15%) TEE and 0.41% (0.26% to 0.64%) VTE during 90-day follow-up. VTE consisted of five pulmonary embolisms (0.11% (0.05% to 0.25%)) and 14 deep venous thrombosis (0.30% (0.18% to 0.50%)). There were four (0.09% (0.04% to 0.23%)) surgery-related deaths, of which 1 (0.02% (0.00% to 0.12%)) was due to pulmonary embolism, and 6 (0.13% (0.06% to 0.28%)) deaths of unknown causes after discharge.
The low incidence of TEE and VTE suggests that in-hospital prophylaxis only, is safe in fast-track THA and TKA patients with LOS of ≤5 days. Guidelines on thromboprophylaxis may need reconsideration in fast-track elective surgery.
The Displaced Femoral (neck fracture) Arthroplasty Consortium for Treatment and Outcomes (DFACTO) study compared total hip arthroplasty (THA) to hemiarthroplasty in the treatment of displaced femoral neck fractures.
This study was designed as a prospective, randomized clinical trial.
The study was conducted in five US academic and private medical centers.
Patients were composed of independent, mentally competent individuals, >50 years old who suffered a displaced femoral neck fracture without existing arthritis at the hip. Forty-one patients were enrolled.
Main outcome measures
Functional outcomes and quality of life were assessed at 6 and 12 months post-fracture using the SF-36, Western Ontario and McMaster University Osteoarthritis Index (WOMAC), the Harris Hip Score, and the Timed “Up & Go” Test (TUG test).
Groups were equivalent at baseline in terms of age, comorbid conditions, and functional status. At 6 months, there were no significant differences between the groups using the outcome measures or overall rates of complications. There was one dislocation in the THA group (5.8% of patients). At 12 months, the THA group reported significantly less pain (53.2 ± 10.2) than the hemiarthroplasty group (42.4 ± 11.5) using the SF-36 (p = 0.02). Using the TUG Test, we observed a greater proportion of THA patients remain functionally independent 1 year after surgery compared the hemiarthroplasty group (p = 0.08, controlling for age and sex).
These differences in pain and functional outcomes suggest THA is a viable treatment option for the active elderly displaced femoral neck fracture population.
displaced femoral neck fracture; total hip arthroplasty; hemiarthroplasty; pain; functional outcomes
Objective To compare characteristics of patients and outcomes after elective surgery in independent sector treatment centres (ISTCs) and NHS providers.
Design Follow-up study with outcomes reported by patients three to six months after surgery.
Setting 25 ISTCs and 72 NHS providers in England.
Population Consecutive patients undergoing hip or knee replacement (5671 in ISTCs and 14 292 in NHS), inguinal hernia repair (640 and 2023, respectively), or surgery for varicose veins (248 and 1336, respectively).
Main outcomes Symptoms and disability reported by patients (Oxford hip and knee scores on a 48 point scale; Aberdeen varicose vein questionnaire) and quality of life (EuroQol EQ-5D score).
Results Patients in ISTCs were healthier than those in NHS providers, had less severe preoperative symptoms, and were more affluent, though the differences were small. With adjustment, patients undergoing joint replacements in NHS providers had poorer outcomes: difference of −1.7 (95% confidence interval −2.5 to −0.9) on the Oxford hip score and −0.9 (−1.6 to −0.2) on the Oxford knee score. They more often reported complications: odds ratio 1.3 (95% confidence interval 1.1 to 1.5) for hip and 1.4 (1.2 to 1.6) for knee. There were no significant differences in outcomes after surgery for hernia or varicose veins, except that NHS patients more often reported poor results after hernia repair (1.4, 1.0 to 1.9) and additional surgery after varicose vein surgery (2.8, 1.2 to 6.8).
Conclusion Patients undergoing surgery in ISTCs were slightly healthier and had less severe conditions than those undergoing surgery in NHS providers. Some outcomes were better in ISTCs, but differences were small compared with the impact ISTCs could have on the provision of elective services.
AIM: To present the 18 year survival and the clinical and radiological outcomes of the Müller straight stem, cemented, total hip arthroplasty (THA).
METHODS: Between 1989 and 2007, 176 primary total hip arthroplasties in 164 consecutive patients were performed in our institution by the senior author. All patients received a Müller cemented straight stem and a cemented polyethylene liner. The mean age of the patients was 62 years (45-78). The diagnosis was primary osteoarthritis in 151 hips, dysplasia of the hip in 12 and subcapital fracture of the femur in 13. Following discharge, serial follow-up consisted of clinical evaluation based on the Harris Hip Score and radiological assessment. The survival of the prosthesis using revision for any reason as an end-point was calculated by Kaplan-Meier analysis.
RESULTS: Twenty-four (15%) patients died during the follow-up study, 6 (4%) patients were lost, while the remaining 134 patients (141 hips) were followed-up for a mean of 10 years (3-18 years). HSS score at the latest follow-up revealed that 84 hips (59.5%) had excellent results, 30 (22.2%) good, 11 (7.8%) fair and 9 (6.3%) poor. There were 3 acetabular revisions due to aseptic loosening. Six (4.2%) stems were diagnosed as having radiographic definitive loosening; however, only 1 was revised. 30% of the surviving stems showed no radiological changes of radiolucency, while 70% showed some changes. Survival of the prosthesis for any reason was 96% at 10 years and 81% at 18 years.
CONCLUSION: The 18 year survival of the Müller straight stem, cemented THA is comparable to those of other successful cemented systems.
Total hip; Replacement; Muller; Straight stem; Cemented; Survivorship
Background and purpose
There has been a limited amount of research on risk factors for revision due to infection following total hip arthroplasty (THA), probably due to low absolute numbers of revisions. We therefore studied patient- and surgery-related risk factors for revision due to infection after primary THA in a population-based setting.
Materials and methods
Using the Danish Hip Arthroplasty Registry, we identified 80,756 primary THAs performed in Denmark between Jan 1, 1995 and Dec 31, 2008. We used Cox regression analysis to compute crude and adjusted relative risk (RR) of revision due to infection. Revision was defined as extraction or exchange of any component due to infection. The median follow-up time was 5 (0–14) years.
597 primary THAs (0.7%) were revised due to infection. Males, patients with any co-morbidity, patients operated due to non-traumatic avascular femoral head necrosis, and patients with long duration of surgery had an increased RR of revision due to infection within the total follow-up time. A tendency of increased RR of revision was found for patients who had received cemented THA without antibiotic and hybrid THA relative to patients with cementless implants. Hip diagnosis and fixation technique were not associated with risk of revision due to infection within 1 year of surgery (short-term risk).
We identified several categories of THA patients who had a higher risk of revision due to infection. Further research is required to explain the mechanism underlying this increased risk. More attention should be paid by clinicians to infection prevention strategies in patients with THA, particularly those with increased risk.
Objectives—To evaluate the performance of a patient assessed outcome measure, the Oxford Hip Score, in a national study of primary hip replacement surgery.
Design—A survey of patients' health status before undergoing primary hip replacement surgery and three months and one year after surgery.
Setting—143 hospitals in three NHS English regions.
Patients—7151 patients admitted for primary total hip replacement surgery over a period of 13 months from September 1996.
Main measures—For patients, Oxford Hip Score and satisfaction with hip replacement and, for surgeons, American Anesthiologists' Society (ASA) classification of physical status.
Results—The response rates to the postal questionnaire at three and 12 months follow up were 85.2% and 80.7%, respectively. Including all three administrations of the questionnaire, all except two items of the Oxford Hip Score were completed by 97% or more respondents and only one item at one administration appeared marginally to reduce the reliability of the score. The effect sizes for changes in the score from baseline to three months was 2.50 and to 12 months was 3.05. Patients rated by surgeons as being healthy preoperatively by the ASA classification were somewhat more likely to return a completed questionnaire at three months (79.4% versus 75.3%) and 12 months (72.4% versus 70.3%) than those rated as having poorer health.
Conclusions—Overall there was little evidence of difficulties for patients in completing the Oxford Hip Score or of unreliable data, except in relation to one questionnaire item. The instrument was very responsive to change over time and score changes for the Oxford Hip Score related well to patients' satisfaction with their surgery. The instrument is an appropriate measure in terms of validity, responsiveness, and feasibility for evaluating total hip replacement from the perspective of the patient.
Key Words: total hip replacement surgery; Oxford Hip Score; questionnaire; assessment
Background Patients with hip osteoarthritis (OA) have muscular weakness, impaired balance, and limp. Deficits in the different limb muscles and their recovery courses are largely unknown, however. We hypothesized that there is persisting muscular weakness in lower limb muscles and an impaired balance and gait 2 years after THA.
Patients and methods 20 elderly patients with unilateral OA were assessed before, and 6 and 24 months after surgery for maximal voluntary isometric strength of hip and knee muscles and by gait analysis, postural stability, and clinical scores (HHS, SF-36, EuroQoL).
Results Hip muscles showed a remaining 6% weakness compared to the contralateral healthy limb 2 years after THA. Preoperatively and 6 months postoperatively, that deficit was 18% and 12%, respectively. Knee extensors fully recovered a preoperative 27% deficit after 2 years. Gait analysis demonstrated a shorter single stance phase for the OA limb compared to healthy limb preoperatively, that had already recovered at the 6-month follow-up. Balance of two-foot standing showed improvement in both sagittal and lateral sway after operation. All clinical scores improved.
Interpretation Muscle strength data demonstrated a slow but full recovery of muscles acting about the knee, but there was still a deficit in hip muscle strength 2 years after THA. Gait and balance recovered after the operation. To accelerate improvement in muscular strength after THA, postoperative training should probably be more intense and target hip abductors.
The Kaiser Permanente National Total Joint Replacement Registry (TJRR) is a national level database designed as a postmarket surveillance system for elective total hip and knee replacement. As of March 31, 2007, the TJRR recorded 16,945 primary total hip arthroplasties (THA), 2144 revisions (11.2%); and 30,815 total knee arthroplasties (TKA), 1794 revisions (5.5%). Statistically significant findings include: older age and higher American Society of Anesthesiology risk scores for revision THAs. Osteoarthritis is the most common diagnosis for THA and TKA, and aseptic loosening and instability are most common in revision THAs and TKAs. The TJRR has provided a mechanism for recalls, identified patients at risk for early revisions and changed practice by providing feedback to physicians.
There is a lack of data on the long-term outcome of total hip arthroplasty procedures, as assessed by validated tools.
We conducted a follow-up study to evaluate the quality of life and functionality of 250 patients an average of 16 years (range: 11-23 years) after total hip arthroplasty using a validated assessment set including the SF-36 questionnaire, Harris Hip Score, WOMAC score, Functional Comorbidity Index, and a study specific questionnaire. Models of multiple stepwise linear and logistic regression analysis were constructed to evaluate the relationships between several explanatory variables and these functional outcomes.
The SF-36 physical indexes of these patients compared negatively with the normative values but positively with the results obtained in untreated subjects with severe hip osteoarthritis. Similar results were detected for the Harris Hip Score and WOMAC score. There was a 96% rate of post-surgical satisfaction. Hip functionality and comorbidities were the most important determinants of physical measures on the SF-36.
Patients who had undergone total hip arthroplasty have impaired long-term self-reported physical quality of life and hip functionality but they still perform physically better than untreated patients with advanced hip osteoarthritis. However, the level of post-surgical satisfaction is high.
The proportion of total hip arthroplasties (THAs) associated with corticosteroid use is uncertain, and the mechanisms of corticosteroid-induced osteonecrosis remain unknown. We sought to evaluate the clinical and radiographic outcomes, complications and satisfaction with THA among patients with corticosteroid-induced osteonecrosis.
We retrospectively assessed functional outcome at a minimum 1-year follow-up using the Western Ontario and MacMaster Universities Arthritis Index (WOMAC); Oxford Hip Score; Short Form (SF)-12; University of California, Los Angeles (UCLA) Activity; and patient satisfaction scores.
We included 31 patients (35 hips). The average follow-up was 20 (range 12–55) months, and the average age at surgery was 47 (range 19–78) years. At follow-up, patients showed significant improvement in all 4 components of the WOMAC (means: function 84, stiffness 75, pain 86, global 84), Oxford-12 (mean 83) and SF-12 (means: mental 40 and physical 48) scores. However, there was no significant improvement in the UCLA Activity scores. Mean patient satisfaction scores were good for pain relief (86), function (80), recreation (77.5) and overall results of surgery (86). Radiographic review at follow-up showed that all components were well fixed with no evidence of loosening. The complication rate was high (17%), with 6 complications in 5 patients (6 of 35 hips). Four patients (4 of 35 hips; 11%) required reoperations.
Total hip arthroplasty in patients with corticosteroid-induced osteonecrosis of the femoral head is successful in reducing pain and improving function; however, the rate of complications and reoperation is high.
Objectives To examine mortality and revision rates among patients with osteoarthritis undergoing hip arthroplasty and to compare these rates between patients undergoing cemented or uncemented procedures and to compare outcomes between men undergoing stemmed total hip replacements and Birmingham hip resurfacing.
Design Cohort study.
Setting National Joint Registry.
Population About 275 000 patient records.
Main outcome measures Hip arthroplasty procedures were linked to the time to any subsequent mortality or revision (implant failure). Flexible parametric survival analysis methods were used to analyse time to mortality and also time to revision. Comparisons between procedure groups were adjusted for age, sex, American Society of Anesthesiologists (ASA) grade, and complexity.
Results As there were large baseline differences in the characteristics of patients receiving cemented, uncemented, or resurfacing procedures, unadjusted comparisons are inappropriate. Multivariable survival analyses identified a higher mortality rate for patients undergoing cemented compared with uncemented total hip replacement (adjusted hazard ratio 1.11, 95% confidence interval 1.07 to 1.16); conversely, there was a lower revision rate with cemented procedures (0.53, 0.50 to 0.57). These translate to small predicted differences in population averaged absolute survival probability at all time points. For example, compared with the uncemented group, at eight years after surgery the predicted probability of death in the cemented group was 0.013 higher (0.007 to 0.019) and the predicted probability of revision was 0.015 lower (0.012 to 0.017). In multivariable analyses restricted to men, there was a higher mortality rate in the cemented group and the uncemented group compared with the Birmingham hip resurfacing group. In terms of revision, the Birmingham hip resurfacings had a similar revision rate to uncemented total hip replacements. Both uncemented total hip replacements and Birmingham hip resurfacings had a higher revision rate than cemented total hip replacements.
Conclusions There is a small but significant increased risk of revision with uncemented rather than cemented total hip replacement, and a small but significant increased risk of death with cemented procedures. It is not known whether these are causal relations or caused by residual confounding. Compared with uncemented and cemented total hip replacements, Birmingham hip resurfacing has a significantly lower risk of death in men of all ages. Previously, only adjusted analyses of hip implant revision rates have been used to recommend and justify use of cheaper cemented total hip implants. Our investigations additionally consider mortality rates and suggest a potentially higher mortality rate with cemented total hip replacements, which merits further investigation.
To study the measurement properties of a joint specific patient
reported outcome measure, a measure of capability and a general
health-related quality of life (HRQOL) tool in a large cohort of
patients with a hip fracture.
Responsiveness and associations between the Oxford Hip Score
(a hip specific measure: OHS), ICEpop CAPability (a measure of capability
in older people: ICECAP-O) and EuroQol EQ-5D (general health-related
quality of life measure: EQ-5D) were assessed using data available
from two large prospective studies. The three outcome measures were assessed
concurrently at a number of fixed follow-up time-points in a consecutive
sequence of patients, allowing direct assessment of change from
baseline, inter-measure associations and validity using a range
of statistical methods.
ICECAP-O was not responsive to change. EQ-5D was responsive to
change from baseline, with an estimated standardised effect size
for the two datasets of 0.676 and 0.644 at six weeks and four weeks
respectively; this was almost as responsive to change as OHS (1.14 at
four weeks). EQ-5D correlated strongly with OHS; Pearson correlation
coefficients were 0.74, 0.77 and 0.70 at baseline, four weeks and
four months. EQ-5D is a moderately good predictor of death at 12
months following hip fracture. Furthermore, EQ-5D reported by proxies
(relatives and carers) behaves similarly to self-reported scores.
Our findings suggest that a general HRQOL tool such as EQ-5D
could be used to measure outcome for patients recovering from hip
fracture, including those with cognitive impairment.
Cite this article: Bone Joint Res 2014;3:69–75.
EQ-5D; Oxford Hip Score; Fragility Fractures; Proximal Femur; ICECAP-O; Outcome assessment