Crosswalks between the Oxford hip and knee scores and the HOOS-12 and KOOS-12 instruments

OBJECTIVE

To develop and validate bi-directional crosswalks between the Oxford Hip Score (OHS) and HOOS-12 summary impact score, and between the Oxford Knee Score (OKS) and KOOS-12 summary impact score.

METHODS

Data were sourced from the Australian Orthopaedic Association National Joint Replacement Registry Patient-Reported Outcome Measures Program. Patients undergoing primary joint replacement for osteoarthritis who completed the OHS and HOOS-12 or OKS and KOOS-12 instruments were included in the analysis. An equipercentile method was used to create four crosswalks, with the distribution of scores smoothed using log-linear models prior to equating. Crosswalk validity was assessed through comparison of actual vs derived scores, Pearson correlation coefficients, root mean square errors (RMSE) and Bland-Altman plots.

RESULTS

Paired OHS/HOOS-12 data and paired OKS/KOOS-12 data were available for 4,513 patients undergoing total hip replacement and 5,942 patients undergoing total knee replacement, respectively. Minimal differences were observed between actual and crosswalk-derived mean scores (actual OHS 27.55 vs derived OHS 27.56; actual HOOS-12 53.28 vs derived HOOS-12 53.31; actual OKS 27.34 vs derived OKS 27.34; actual KOOS-12 50.51 vs derived KOOS-12 50.58). High correlation was observed between actual and derived scores (Pearson's r for hip-specific instruments: 0.943-0.946; Pearson's r for knee-specific instruments: 0.925-0.931). Plotted actual vs mean derived scores also indicated robust concordance across the breadth of the instrument scales.

CONCLUSION

These crosswalks provide close approximations of actual OHS, OKS, HOOS-12 and KOOS-12 scores, as indicated by multiple validation metrics. They offer a resource for clinicians, researchers and arthroplasty registries to support PROMs score conversion and data harmonisation efforts.

Rates, costs, return to work and reoperation following spinal surgery in a workers' compensation cohort in New South Wales, 2010-2018: a cohort study using administrative data

BACKGROUND

Internationally, elective spinal surgery rates in workers' compensation populations are high, as are reoperation rates, while return-to-work rates following spinal surgery are low. Little information is available from Australia. The aim of this study was to describe the rates, costs, return to work and reoperation following elective spinal surgery in the workers' compensation population in New South Wales (NSW), Australia.

METHODS

This retrospective cohort study used administrative data from the State Insurance Regulatory Authority, the government organisation responsible for regulating and administering workers' compensation insurance in NSW. These data cover all workers' compensation-insured workers in New South Wales (over 3 million workers/year). We identified a cohort of insured workers who underwent elective spinal surgery (fusion or decompression) between January 1, 2010 and December 31, 2018. People who underwent surgery for spinal fracture or dislocation, or who had sustained a traumatic brain injury were excluded. The main outcome measures were annual spinal surgery rates, cost of the surgical episode, cumulative costs (surgical, hospital, medical and physical therapy) to 2 years post-surgery, and reoperation and return-to-work rates 2 years post-surgery.

RESULTS

There were 9343 eligible claims (39.1 % fusion; 59.9 % decompression); claimants were predominantly male (75 %) with a mean age of 43 (range 18 to 75) years. Spinal surgery rates ranged from 15 to 29 surgeries per 100,000 workers per year, fell from 2011-12 to 2014-15 and rose thereafter. The average cost in Australian dollars for a surgical episode was $46,000 for a spinal fusion and $20,000 for a decompression. Two years post-fusion, only 19 % of people had returned to work at full capacity; 39 % after decompression. Nineteen percent of patients underwent additional spinal surgery within 2 years of the index surgery, to a maximum of 5 additional surgeries.

CONCLUSION

Rates of workers' compensation-funded spinal surgery did not rise significantly during the study period, but reoperation rates are high and return-to-work rates are low in this population at 2 years post- surgery. In the context of the poor evidence base supporting lumbar fusion surgery, the high cost, increasing rates, and the increased likelihood of poor outcomes in the workers' compensation population, we question the value of this procedure in this setting.

Observing the use of knee arthroplasty appropriateness tools in clinical practice: do appropriateness criteria tools predict surgeon decision-making?

OBJECTIVE

The primary aim of this study was to evaluate the agreement between surgeons and two validated total knee arthroplasty (TKA) appropriateness tools, and secondarily to compare Australian appropriateness rates to those reported internationally.

METHODS

A consecutive sample of patients from one public hospital arthroplasty clinic and a convenience sample from private rooms of surgeons in New South Wales, Australia (n = 11), referred for surgical opinion regarding TKA were enrolled over 1 year. Surgeons applied appropriateness tools created by Escobar et al. and the American Academy of Orthopaedic Surgeons (AAOS). Correlation between the appropriateness tools and surgeon's decisions were evaluated.

RESULTS

There were 368 patients enrolled, and contrasting rates of being "appropriate" for surgery were identified between the Escobar (n = 109, 29.6%) and AAOS (n = 292, 79.3%) tools. Surgeon agreement with the Escobar tool was substantial (ĸ = 0.61, 95%CI: 0.53-0.69) compared to slight with the AAOS tool (ĸ = 0.11, 95%CI: 0.06-0.16). Of those advised against TKA (n = 179, 48.6%), the AAOS tool suggested many patients (n = 111, 62.0%) were "appropriate" compared to the Escobar tool (n = 12, 6.7%).

CONCLUSIONS

Surgeons rated patients seeking opinion for TKA as appropriate over half the time, however the AAOS tool had low correlation with surgeons as opposed to the Escobar tool. This was illustrated by both tools rating a majority of patients to be operated on as appropriate, but only the AAOS tool considering most patients not chosen for surgery to be appropriate. When comparing previously published appropriateness rates, appropriateness in Australia, USA, Spain and Qatar was found to be similar.

Performance of the HOOS-12 and KOOS-12 instruments for evaluating outcomes from joint replacement surgery

OBJECTIVE

To evaluate the psychometric properties of the 12-item Hip disability and Osteoarthritis Outcome Score (HOOS-12) and Knee injury and Osteoarthritis Outcome Score (KOOS-12) for use in evaluating outcomes after joint replacement for osteoarthritis.

DESIGN

Patient-reported outcomes data collected by the Australian Orthopaedic Association National Joint Replacement Registry were used for this analysis. HOOS-12 and KOOS-12 domain (pain, function, quality of life) and summary impact data were available. The Oxford Hip Score (OHS), Oxford Knee Score (OKS) and EQ-5D-5L were used as comparators. Instruments were administered pre-operatively and at 6 months post-operatively. Internal consistency reliability, floor and ceiling effects, convergent validity, known groups validity, and responsiveness were evaluated using standard psychometric techniques.

RESULTS

Baseline HOOS-12 and KOOS-12 data were available for 3,023 patients undergoing primary total hip replacement and 4,010 patients undergoing primary total knee replacement. At baseline, high internal consistency was demonstrated for all domains and summary scores (Cronbach's alpha: HOOS-12 = 0.81-0.93; KOOS-12 = 0.82-0.92). Post-operative ceiling effects (>15% of patients scoring the best possible score) were identified for the HOOS-12 pain (46%), function (39%) and quality of life domains (26%) and summary score (17%), and for the KOOS-12 pain (21%) and function domains (18%). The HOOS-12 and KOOS-12 could differentiate between two known groups (lowest/highest OHS or OKS quartiles post-operatively; p < 0.001) and were highly responsive to change (effect sizes for HOOS-12: 2.20-2.83; KOOS-12: 1.82-2.35).

CONCLUSION

The HOOS-12 and KOOS-12 have good psychometric properties for capturing joint replacement outcomes including excellent responsiveness, although ceiling effects may limit monitoring of post-operative improvement.

Practice variation in total hip arthroplasty versus hemiarthroplasty for treatment of fractured neck of femur in Australia

Aims

Displaced femoral neck fractures (FNF) may be treated with partial (hemiarthroplasty, HA) or total hip arthroplasty (THA), with recent recommendations advising that THA be used in community-ambulant patients. This study aims to determine the association between the proportion of FNF treated with THA and year of surgery, day of the week, surgeon practice, and private versus public hospitals, adjusting for known confounders.

Patients and Methods

Data from 67 620 patients in the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) from 1999 to 2016 inclusive were used to generate unadjusted and adjusted analyses of the associations between patient, time, surgeon and institution factors, and the proportion of FNF treated with THA.

Results

Overall, THA was used in 23.7% of patients. THA was more frequently used over time, in younger patients, in healthier patients, in cases performed on weekdays (adjusted odds ratio (OR) 1.27; 95% confidence interval (CI) 1.14 to 1.41), in private hospitals (adjusted OR 4.34; 95% CI 3.94 to 4.79) and by surgeons whose hip arthroplasty practice has a relatively higher proportion of elective patients (adjusted OR 1.65; 95% CI 1.49 to 1.83).

Conclusion

Practice variation exists in the proportion of FNF patients treated with THA due to variables other than patient factors. This may reflect variation in resources available and surgeon preference, and uncertainty regarding the relative indication.

A Comparison of Plain Radiography with Computer Tomography in Determining Coronal and Sagittal Alignments following Total Knee Arthroplasty

Introduction: Optimal coronal and sagittal component positioning is important in achieving a successful outcome following total knee arthroplasty (TKA). Modalities to determine post-operative alignment include plain radiography and computer tomography (CT) imaging. This study aims to determine the accuracy and reliability of plain radiographs in measuring coronal and sagittal alignment following TKA.

Materials and Methods: A prospective, consecutive study of 58 patients undergoing TKA was performed comparing alignment data from plain radiographs and CT imaging. Hip-knee-angle (HKA), sagittal femoral angle (SFA) and sagittal tibial angle (STA) measurements were taken by two observers from plain radiographs and compared with CT alignment. Intra- and inter-observer correlation was calculated for each measurement.

Results: Intra-observer correlation was excellent for HKA (r>0.89) with a mean difference of <1.9°. The least intra-observer correlation was for SFA (mean r=0.58) with a mean difference of 8°. Inter-observer correlation was better for HKA (r>0.95) and STA (r>0.8) compared to SFA (r=0.5). When comparing modalities (radiographs vs CT), HKA estimations for both observers showed the least maximum and mean differences while SFA observations were the least accurate.

Conclusion: Radiographic estimation of HKA showed excellent intra- and inter-observer correlation and corresponds well with CT imaging. However, radiographic estimation of sagittal plane alignment was less reliably measured and correlated less with CT imaging. Plain radiography was found to be inferior to CT for estimation of biplanar prosthetic alignment following TKA.

An equivalence study: Are patient-completed and telephone interview equivalent modes of administration for the EuroQol survey?

Background

To determine if the EuroQol Health Related Quality of Life survey produces equivalent results when administered by phone interview or patient-completed forms.

Methods

People awaiting hip or knee arthroplasty at a major metropolitan hospital participated. They were randomly assigned to receive the EuroQol Health Related Quality of Life survey via telephone, followed by a patient completed form 1 week later, or vice versa. Equivalence was determined using two one-sided tests (TOST) based on minimal clinically-important differences for the visual analogue scale (VAS) and the summary Utility Index. Cohen’s Kappa scores were computed to determine agreement for the individual EuroQoL Likert scale items.

Results

Seventy-six from 90 (84%) participants completed the survey twice. Based on limits set at ±7 and ±0.11 for the VAS and Utility Index, respectively, equivalence was established between the two methods of administration for both the VAS (mean difference 0.05 [90% CI −3.76–3.67]) and the Utility Index (mean difference 0.06 [90% CI 0.02–0.11]). Varying levels of agreement, ranging from slight to substantial (κ = 0.17–0.67), were demonstrated for the individual health domains. The order of telephone and patient-completed survey administration had no significant effect on results.

Conclusions

Equivalent results are obtained between telephone and patient-completed administration for the VAS and Utility Index of the EuroQol Survey in people with advanced hip or knee osteoarthritis. The limits of agreement for the individual health domains vary which prevents the accurate interpretation of real change in these items across modes.

Clinical and financial benefits of intra-articular tranexamic acid in total knee arthroplasty

PURPOSE

To determine whether intra-articular tranexamic acid (TXA) use after total knee arthroplasty (TKA) results in decreased postoperative blood transfusion and length of hospital stay.

METHODS

Medical records of 1981 patients (mean age, 69.2 years) who underwent primary TKA with (n=1006) or without (n=975) TXA use by any of 4 knee arthroplasty surgeons were reviewed. TXA (3000 mg/30ml) was administered via an epidural catheter into the knee joint after wound closure. Postoperative blood transfusion was given to patients with haemoglobin (Hb) level <80 g/dl on days 1 and 2 or with symptoms of acute anaemia.

RESULTS

Intra-articular TXA use after TKA resulted in a lower blood transfusion rate (4.5% [45/1006] vs. 14.8% [144/975], p<0.0001), fewer units of blood transfused (86 vs. 313 units, p<0.0001), fewer units of blood transfused per 100 patients (8.5 vs. 32.1, p<0.0001), and shorter length of hospital stay (4.7±2.3 vs. 5.3±2.7 days, p<0.0001). Total cost savings with respect to the reduction in blood transfusion was AU$143.68 per patient. When the change in length of hospital stay and TXA costs were included, the overall saving was AU$631.36 per patient.

CONCLUSION

Intra-articular TXA use can reduce costs as a result of decreased blood transfusion rate and length of hospital stay in patients undergoing TKA.

Presence and predictors of persistent pain among persons who sustained an injury in a road traffic crash

BACKGROUND

There is a paucity of prospective studies with long follow-up that have examined a wide range of correlates associated with persistent pain outcomes in persons who sustained a mild or moderate injury in a road traffic crash. This study aimed to establish the independent predictors of pain severity over 24 months.

METHODS

A total of 364, 284 and 252 persons with mild/moderate musculoskeletal injuries sustained in a vehicle-related crash participated in telephone interviews in the subacute phase, and at 12 and 24 months, respectively. The numeric rating scale (NRS) assessed pain severity. Pain-Related Self-Statements Scale-Catastrophizing (PRSS-Catastrophizing) and the Short Form Orebro Musculoskeletal Pain Screening Questionnaire (OMPSQ) were also administered.

RESULTS

After multivariable adjustment, each 1 SD increase in Short Form-12 Physical Component Score (SF-12 PCS) in the subacute phase was associated with 0.73 (p = 0.002) and 1.11 (p < 0.0001) decrease in NRS scores after 12 and 24 months, respectively. Each unit increase in the PRSS-Catastrophizing score in the subacute phase was associated with 0.54 (p = 0.001) and 0.43 (p = 0.03) increase in NRS scores 12 and 24 months later, respectively. Subacute phase OMPSQ scores were positively associated with NRS scores at 12- and 24-month follow-ups (p < 0.0001).

CONCLUSIONS

Self-perceived physical well-being, pain-related work disability and pain catastrophizing could play a role in determining long-term pain-related outcomes following traffic-related injuries.

Mail versus telephone administration of the Oxford Knee and Hip Scores

Telephone and postal methods of administration of the Oxford Knee Score (OKS) and the Oxford Hip Score (OHS) were compared on 85 and 61 patients undergoing total knee arthroplasty (TKA) and total hip arthroplasty (THA), respectively. The test for equivalence was significant for both the knee (P<0.001) and hip participants (P<0.001) indicating that the modes of administration yielded similar results. The ICCs of the OKS and OHS were 0.79 (95% Confidence Interval (CI) 0.70, 0.86) and 0.87 (0.79, 0.92) respectively. The 95% limits of agreement were wide for both scores (OKS LOA, -8.6, 8.2; OHS LOA, -7.7, 5.3). The two modes of administration of the OKS and OHS produce equivalent survey responses at a group level but the same method of administration should be constant for individual monitoring in a clinical setting.

Practice variation in common fracture presentations: a survey of orthopaedic surgeons

BACKGROUND

Practice variation may indicate a lack of clear evidence to guide treatment. This study aims to quantify practice variation for common orthopaedic fractures, and to explore possible predictors of the variation.

MATERIALS AND METHODS

A nationwide electronic survey of Australian orthopaedic surgeons was performed. Five common fractures (ankle, scaphoid, distal radius, neck of humerus, and clavicle) were presented. Data on management preferences and surgeon background were gathered. Potential predictors of operative (vs. non-operative) treatment were explored.

RESULTS

358 of 760 (47%) surgeons responded. For the ankle, undisplaced scaphoid, distal radius, neck of humerus and clavicle fractures, operative treatment was chosen in 40%, 44%, 77%, 26% and 38%, respectively. Operative treatment was significantly more likely to be chosen by more junior surgeons, and by surgeons specialising in the affected area (i.e., shoulder surgeons for clavicle and neck of humerus fractures, and hand surgeons for scaphoid and distal radius fractures).

CONCLUSIONS

Variations exist in the management of common fractures. Variation may represent legitimate improvisation for varying clinical scenarios, but it may reflect clinician bias, which in turn, may contribute to varying standards of care for the management of common conditions.

Intramedullary nailing versus fixed angle blade plating for subtrochanteric femoral fractures: a prospective randomised controlled trial

PURPOSE

To compare closed intramedullary nailing to open reduction and internal fixation using a fixed angle blade plate for the management of subtrochanteric femoral fractures.

METHODS

58 patients were equally randomised to undergo either an intramedullary nailing (IN) or fixed angle blade plating (BP).

RESULTS

There were no significant differences between the 2 groups with regard to age, time to surgery, operating time, receipt of blood transfusions, duration of hospital stay, or fracture classification. The revision rate was 28% (8/29) in the BP group and none in the IN group; the difference was statistically significant.

CONCLUSION

Internal fixation using a fixed angle blade plate for subtrochanteric femoral fractures has higher implant failure and revision rates, compared to closed intramedullary nailing.

Orthopaedic trauma surgery performed by unsupervised and supervised trainees: complication rates compared

PURPOSE

To compare the complication rates associated with orthopaedic trauma surgery performed by unsupervised and supervised trainees.

METHODS

In our hospital, 6361 orthopaedic trauma operations were performed between 1 January 1998 and 31 December 2002. Data pertinent to the surgeon's supervision and postoperative complications were collected. Elective operations were excluded, as consultants were almost always present. Complication rates ensuing in unsupervised and supervised groups were compared using the Chi squared test.

RESULTS

Of 6361 orthopaedic trauma operations performed, 3754 (59%) were by unsupervised trainees of varying experience, whereas 2494 (39%) were by supervised trainees or consultants. In 113 (2%) of the operations, the supervision status was not recorded. The complication rate was significantly higher in the supervised than unsupervised group (5.3 vs 3.3%, Chi squared=15, df=1, p=0.0001).

CONCLUSION

The complication rate was not higher for operations performed by unsupervised trainees than those performed in the presence of a consultant.

Publication bias in abstracts presented to the annual meeting of the American Academy of Orthopaedic Surgeons

PURPOSE

To examine possible causes of publication bias in the orthopaedic literature so as to avoid inappropriate clinical decisions based on reviews of the literature.

METHODS

Two reviewers independently reviewed abstracts presented to the 1999 American Academy of Orthopaedic Surgeons annual meeting. Data pertaining to sample size, statistical significance, study setting, country of origin, outcome, study type, and sponsorship were extracted from each abstract. The publication rate was measured after 5 years, by electronic searching and author contact. Predictors of publication were identified using logistic regression analysis.

RESULTS

Of the 318 abstracts listed in the proceedings, 175 (55%) were published within 5 years. Publication was associated with positive rather than neutral outcomes (odds ratio, 1.62; 95% confidence interval, 1.01-2.59; p<0.05) and with the reporting of statistical significance (odds ratio, 2.05; 95% confidence interval 1.24-3.39; p=0.005). Sponsorship, country of origin, sample size, study setting, and study type did not significantly influence the publication rate.

CONCLUSION

Evidence of publication bias exists in abstracts presented at the 1999 American Academy of Orthopaedic Surgeons annual meeting. Clinical decisions based on the literature may be biased due to an over-representation of studies with positive outcomes.

The fate of the syndesmosis in type C ankle fractures: a cadaveric study

Ankle fractures that involve a fracture of the fibula above the syndesmosis (AO type C) associated with a medial lesion are always said to indicate rupture of the inferior tibiofibular syndesmosis. This study shows that fresh cadaver ankles subjected to a combination of abduction and direct lateral force over the shaft of the fibula consistently produce displaced bimalleolar ankle fractures without disruption of the inferior tibiofibular syndesmosis. The results of this study suggest that the presence of an AO type C ankle fracture does not necessarily indicate diastasis of the inferior tibiofibular joint and, therefore, internal fixation of the syndesmosis of the fracture may not be indicated.

Manganese, selenium and other trace elements in spinal cord, liver and bone in motor neurone disease

Trace element levels were measured by neutron activation analysis in spinal cord, liver and bone of 7 control patients dying of non-neurological disease and 15 patients dying of motor neurone disease (MND). The concentration of selenium was significantly elevated in the cervical cord, liver and bone in the MND group. Although spinal cord manganese levels were increased at both the cervical and thoracic levels, the hepatic concentration was reduced in the MND patients. These findings are discussed in relation to current understanding of the pathogenesis of MND.

Trace elements in the spinal cord and other tissues in motor neuron disease

Trace elements were estimated in the spinal cord, liver and bone of five patients dying of motor neuron disease and five control subjects dying of non-neurological disease. The content of selenium in cord and liver and the cord manganese level were significantly increased in the motor neuron disease patients. These findings are discussed in terms of the possible aetiology of motor neuron disease.

Trace elements in cerebrospinal fluid in motor neurone disease

Concentrations of sodium, chlorine, potassium, chromium, iron, cobalt, zinc, rubidium, silver, caesium, and selenium in cerebrospinal fluid from 14 control subjects and 20 patients with motor neurone disease were measured by in vitro neutron activation analysis. No statistically significant correlation was found between the concentrations of any two elements other than sodium and chlorine in either the patient or control group (r = 0.9905; p less than 0.001). The mean cobalt concentration was significantly lower in the patients (p = 0.0015). No other statistically significant difference was shown. The relevance of this finding was examined in relation to current concepts of the pathogenesis of motor neurone disease and the role of cobalt in cellular metabolism.

Analysis of minor and trace elements in gallstones by induction of characteristic ionising radiation

In an investigation of the role of trace elements in gallstone formation and of minor and trace elements in gallstone and bile, samples from five patients were analysed using three different techniques for cross-verification: NAA, PIXE, and XRF. In addition, certified standards of bovine liver and oyster tissue from the NBS, Washington, were re-analysed using the different techniques to confirm the accuracy of the experimental procedures. NAA of five gallstones was used for the quantitative analysis of 19 elements with Z greater than 11. The concentrations of Cl, K + Ca, Mn, Fe and Cu + Zn were determined by PIXE and those of Mg, P, S, K and Ca by XRF. In most cases the concentrations were in the range of a few PPB to a few hundred PPM. The spatial distribution of the component elements was obtained using XRF with a scanning electron microscope and the results demonstrated that calcium was present centrally in all the stones. The analysis of gallbladder bile from four patients showed that the calcium concentration was much greater than normal, indicating that calcium and other elements play an important role in stone formation. Infrared spectroscopy showed that the calcium salts were present in gallstones in three compound forms: calcium carbonate, calcium phosphate and calcium bilirubinate. Reasons for the cause of calcium precipitation are discussed.

The distribution and retention of cadmium 115m in the rat following injection into the prostate

The gonadal effects produced by injection of cadmium in the rats are well known. The effects of direct injection into the prostate are less well understood. The present experiments indicated the retention of cadmium by the various lobes of the rat prostate following direct injection of radioactive cadmium into the organ. The cells of the prostate are capable of retaining cadmium in measurable amounts up to at least 6 weeks following the injection. The subcellular fractions were measured with respect to cadmium activity and these are indicated. In addition measurements were made in organs which are known to be affected by cadmium, that is, kidney and the testicle. The affinity of the kidney for cadmium is confirmed. The areas of the prostate gland with a high zinc content appear to retain less cadmium than areas of the gland which are known to have a low zinc content. This suggests a possible zinc protective mechanism.