Comparison of the responsiveness of the SF-36, the Oxford Knee Score, and the Knee Society Clinical Rating System in patients undergoing total knee replacement.

OBJECTIVES: To compare the responsiveness of the Knee Society (KS) Clinical Rating System, the general health status measure Short Form 36 (SF-36), and both the raw and Rasch-based scores of the condition-specific Oxford Knee Score (OKS) in patients undergoing total knee replacement (TKR) METHODS: Data were prospectively collected as part of routine care from adult patients who underwent TKR between 2001 and 2006. OKS data fit the Rasch partial credit model after removing items regarding limping and kneeling. Responsiveness was assessed using effect size (ES), standardised response mean (SRM), and relative validity (RV). RESULTS: Among 702 patients with complete data at baseline and two follow-ups, the pain subscale of the KS (KS-P), raw-OKS, and Rasch-OKS consistently had higher levels of responsiveness than all eight SF-36 and the other KS subscales. At 6-month follow-up, Rasch-OKS had the largest ES and KS-P had the largest SRM (2.7 and 2.0, respectively). When compared to raw-OKS, the RVs of KS-P, Rasch-OKS, SF-36 bodily pain, and SF-36 physical functioning were 1.1, 0.66, 0.49, and 0.36, respectively. A similar ordering of responsiveness was observed at 24-month follow-up. CONCLUSION: The OKS and KS-P are more responsive than most SF-36 subscales in TKR patients. Raw-OKS and Rasch-OKS have comparable responsiveness. Different responsiveness indices may give different results.

Health-related quality of life after total knee replacement or unicompartmental knee arthroplasty in an urban asian population.

OBJECTIVE: To examine health-related quality of life (HRQoL) after total knee replacement (TKR) or unicompartmental knee arthroplasty (UKA). METHODS: Asian adult patients undergoing either TKR or UKA in a hospital in Singapore between 2001 and 2006 were interviewed before surgery and 6 and 24 months postoperatively to obtain demographic information and HRQoL scores using the Short Form-36 Health Survey (SF-36) and the Oxford Knee Score (OKS). RESULTS: Data were collected from 2243, 1715, and 1113 patients at baseline and at 6 and 24 months, respectively. TKR patients had a lower preoperative OKS than UKA patients and lower preoperative scores on four subscales of the SF-36 (P < 0.01). Both TKR and UKA patients' OKS and SF-36 subscale scores improved 6 months postoperatively except in the general health domain. SF-36 role physical and bodily pain scores showed the most improvement (40.9 and 33.0 points in TKR and 36.9 and 31.4 points in UKA patients, respectively). Two years after surgery, TKR patients' SF-36 scores and OKSs were not significantly different from those of UKA patients except for physical functioning scores. Multiple regression analysis adjusting for demographics showed that baseline scores were a significant predictor of the postoperative OKSs and scores on all SF-36 subscales (P < 0.01), whereas the type of surgery was not associated with the postoperative scores. CONCLUSIONS: Both TKR and UKA patients experienced significant improvements in HRQoL, particularly in the role physical and pain domains. After controlling for potential confounding variables, the type of surgery was not a significant predictor of patients' postoperative HRQoL scores.

Effects of periarticular steroid injection on knee function and the inflammatory response following Unicondylar Knee Arthroplasty.

There is little information on the values of CRP and ESR as markers for inflammation in Unicondylar Knee Arthroplasty. The effect of periarticular steroid injection in post-operative pain relief and clinical recovery has not been well studied. Eighty-three consecutive patients undergoing primary UKAs were randomized to receive either an intra-operative periarticular injection with a local anaesthetic and adrenaline or with the addition of triamcinolone acetonide. CRP and ESR values, pain VAS and other scores, as well as clinical functional parameters, were obtained and analysed. Patients were assessed daily till discharge and up to 6 months post-operatively. Plasma CRP and ESR fluctuate after a UKA, with normalizing values indicating uneventful recovery. Periarticular steroid injections reduce post-operative pain and inflammation, and are clinically relevant as they improve short-term functional recovery and clinical parameters, resulting in better outcomes for patients without having major complications.

Continuous infiltration of local anaesthetic following total knee arthroplasty.

PURPOSE: To determine whether continuous infiltration of local anaesthetic can reduce the pain score and morphine use over 48 hours after total knee arthroplasty (TKA). METHODS: 11 men and 43 women aged 50 to 82 years who underwent unilateral TKA for osteoarthritis were recruited. They were randomised into 3 groups. In group 1, 17 patients who acted as controls received patient-controlled analgesia (PCA) with intravenous morphine for 48 hours. In group 2, 16 patients received continuous infiltration of bupivacaine to the subcutaneous tissue and intra-articular space for 48 hours, in addition to PCA. In group 3, 21 patients received an intra-articular injection of local anaesthetic, followed by continuous infiltration of bupivacaine to the subcutaneous tissue and intraarticular space for 48 hours, in addition to PCA. For each patient, a visual analogue score (VAS) for pain was recorded postoperatively at 2, 4, 6, 12, 24, 36, and 48 hours. The total amount of morphine used was recorded at 24 and 48 hours. RESULTS: Over 48 hours, the VAS for pain and morphine use was significantly higher in controls than patients in groups 2 and 3. CONCLUSION: Continuous infiltration of local anaesthetic into the intra-articular space and subcutaneous tissues, in addition to PCA with intravenous morphine, provides significantly more pain relief and reduces morphine use.

Continuous femoral nerve block in total knee arthroplasty: immediate and two-year outcomes.

We conducted a prospective study to investigate the immediate and 2-year outcomes of total knee arthroplasty patients who received continuous femoral nerve block (FNB) for analgesia. Sixty patients undergoing unilateral total knee arthroplasty were randomized into 3 groups and received high-dose continuous FNB, low-dose continuous FNB, or no FNB. In the immediate postoperative period, we studied their pain scores, cumulative morphine use, any FNB-related complications, time of first ambulation, and patient satisfaction. At 2 years, we assessed their functional outcomes with Oxford knee questionnaire and Knee Society clinical rating system. Immediately after surgery, there was less pain, higher satisfaction, and lower morphine use among patients on continuous FNB regardless of ropivacaine dosage used. At 2 years, there were no significant differences in functional outcomes.

A study on indirect and intangible costs for patients with knee osteoarthritis in Singapore.

OBJECTIVES: To estimate indirect costs through human capital approach and intangible costs through willingness-to-pay (WTP), and identify factors potentially affecting these costs in multiethnic Asian patients with knee osteoarthritis (OA). METHODS: Data were collected through face-to-face interviews among knee OA patients. Human capital approach was used to estimate indirect costs by multiplying: 1) days of absence from work because of OA, with average earnings per capita per day for working patients; or 2) productivity loss with the market price of housekeeping for retirees/homemakers. A closed-ended iterative bidding contingent valuation method was used to elicit willingness-to-pay for a hypothetical cure of OA as a proxy for intangible costs. Mann-Whitney U or Kruskal-Wallis H-tests were performed in univariate analyzes, and linear regression in multivariate analyses. RESULTS: Indirect costs per year and intangible costs were estimated at US$1008 and US$1200, accounting for 2.8% and 3.3% of annual household income, respectively. The indirect costs were significantly higher for male or working patients, while intangible costs were higher for Chinese, working patients, with higher income, or worse global well-being. CONCLUSION: This study demonstrated that eliciting indirect costs through human capital approach and intangible costs through WTP are acceptable and feasible in Asian patients with knee OA. Besides the direct costs, the indirect and intangible costs for the OA patients could be substantial.

Validation of Chinese Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) in patients scheduled for total knee replacement.

OBJECTIVE: Our aim was to cross-culturally validate Chinese Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) in patients with knee osteoarthritis (OA) scheduled for total knee replacement in Singapore. METHODS: Chinese WOMAC was translated from the original English version following standard guidelines. Patients were asked to complete a questionnaire containing the WOMAC (twice within 6 days), the Short Form 36 (SF-36), and the EuroQoL EQ-5D. Reliability was assessed using Cronbach's alpha and intraclass correlation coefficients (ICC), dimensionality using item-to-domain correlations and factor analyses. Convergent and discriminant construct validity was assessed using six each a priori hypotheses. RESULTS: Chinese WOMAC was well accepted by the patients in the pilot test. The Chinese and English versions were therefore administered to a consecutive sample of 131 Chinese- and 127 English-speaking subjects, respectively, with knee OA. Cronbach's alpha exceeded 0.7 for all domains except for Chinese pain domain, whereas the ICC exceeded 0.7 for all domains. Hypothesized item-to-domain correlations were observed for all items except for four items in Chinese physical function domain. The factor analyses yielded seven and five factors with eigenvalues of more than 1.0 in the Chinese and English versions, respectively. A total of 10/12 a priori construct validity hypotheses were satisfied for the Chinese version. Weak correlations between WOMAC pain and SF-36 bodily pain and moderate correlation between WOMAC pain and EQ-5D anxiety/depression were observed. CONCLUSIONS: Chinese WOMAC was well accepted and demonstrated acceptable psychometric properties in Singaporean patients with severe knee OA.

Computer-assisted minimally invasive total knee arthroplasty compared with standard total knee arthroplasty. A prospective, randomized study.

BACKGROUND: There is little information on the feasibility of computer navigation when using a minimally invasive approach for total knee arthroplasty, during which the anatomic landmarks for registration may be obscured. The purpose of the present study was to determine the radiographic accuracy of this technique and to compare the rate of functional recovery between patients who underwent computer-assisted minimally invasive arthroplasty and those who underwent conventional total knee arthroplasty. METHODS: One hundred and eight consecutive patients were randomized to undergo computer-assisted minimally invasive total knee arthroplasty or conventional total knee arthroplasty. Perioperative pain management was standardized. The clinical parameters, long-leg radiographs, and functional assessment scores were evaluated for six months postoperatively. RESULTS: Patients who underwent computer-assisted minimally invasive total knee arthroplasty had a significantly longer operative time (by a mean of twenty-four minutes) and a significantly shorter inpatient stay (3.3 compared with 4.5 days) in comparison with those who underwent conventional arthroplasty (p

Randomized controlled trial comparing the radiologic outcomes of conventional and minimally invasive techniques for total knee arthroplasty.

The objective of this study was to compare the radiologic outcomes of total knee arthroplasty using the conventional technique with those using minimally invasive surgery (MIS) techniques. Ninety patients were randomized to undergo conventional (control), MIS mini-incision mid-vastus (mini), or MIS side-cutting (side cut) techniques for their total knee arthroplasty. Long-leg radiographs were assessed postoperatively. The mean overall limb varus alignments were 1.03 degrees (SD, 2.58 degrees ) for the control group, 0.87 degrees (SD, 2.96 degrees ) for the mini group, and 0.37 degrees (SD 4.27 degrees ) for the side cut group. The mean overall limb alignments within +/-3.0 degrees varus/valgus were 83.3%, 83.3%, and 56.7%, respectively. Femoral implant placement (P = .028) and overall limb alignment (P = .024) in the side cut group were significantly poorer as compared with those in the control group. The side cut group also had more outliers in the coronal plane. Results were comparable between the mini and control groups. The side cut technique appears to affect the accuracy of implant placement.

Comparison of the EuroQol and short form 6D in Singapore multiethnic Asian knee osteoarthritis patients scheduled for total knee replacement.

OBJECTIVE: To compare the EuroQol (EQ-5D) and Short Form 6D (SF-6D) among multiethnic Asian patients with knee osteoarthritis (OA) scheduled for total knee replacement in Singapore. METHODS: Patients were asked to complete questionnaires including the EQ-5D, Short Form 36, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and Lequesne knee index. EQ-5D and SF-6D utility scores were calculated using the scoring algorithms developed from the UK general population. Agreement between the 2 instruments was assessed by comparing their score distributions, means, medians, intraclass correlation coefficients (ICCs), and a Bland-Altman plot. Correlations of the EQ-5D and SF-6D with WOMAC and Lequesne knee index scores were also examined. RESULTS: A consecutive sample of 258 knee OA patients (127 English-speaking and 131 Chinese-speaking) participated. The mean +/- SD EQ-5D utility score was 0.49 +/- 0.31 (range -0.25-1.00) and the mean SF-6D utility score was 0.63 +/- 0.12 (range 0.32-0.89). In a hypothetical example, this 0.14-point difference in mean utility scores yielded a difference of $10,000/quality-adjusted life year (QALY) in cost-effectiveness ratios. The score distribution was bimodal for the EQ-5D and normal for the SF-6D. This poor agreement was also demonstrated by the Bland-Altman plot and the low ICC (range 0.18-0.54). Correlations of the WOMAC and Lequesne index with the EQ-5D were higher than with the SF-6D. CONCLUSION: Using different preference-based health-related quality of life instruments may yield different utility scores, which could have a great impact on QALY estimates. This highlights the importance of selecting appropriate instruments for economic evaluation. Additional research is needed to determine which instrument (the EQ-5D or the SF-6D) should be used in OA patients.

Direct and indirect costs of osteoarthritis in Singapore: a comparative study among multiethnic Asian patients with osteoarthritis.

OBJECTIVE: To estimate and compare the direct and indirect costs of osteoarthritis (OA) in multiethnic Asian patients with OA in Singapore. METHODS: The study was a retrospective and cross-sectional design. Patients were stratified according to ethnicity and presence or absence of joint surgery. Direct costs were estimated from both a societal and a patient perspective using the Singapore General Hospital database; indirect costs were estimated using the human capital approach. All costs were expressed as mean costs per patient per annum in 2003 Singapore dollars. RESULTS: A total of 1179 patients (83.6% Chinese, 7.2% Malay, 3.5% Indian, 5.7% others) were included in estimating direct costs, of which 513 (43.5%) had total knee replacement (TKR) and 92 (7.8%) total hip replacement (THR), while 105 patients (71.4% Chinese, 14.3% Malay, 14.3% Indian) were included in estimating indirect costs. Direct costs to patients ranged from 1460 dollars to 7477 dollars for Chinese, 1362 dollars-7211 dollars for Malays, 1688 dollars-6226 dollars for Indians, and 1437 dollars-12,140 dollars for other ethnic patients; direct costs to society ranged from 3351 dollars to 15,799 dollars for Chinese, 2939 dollars-15,436 dollars for Malays, 3150 dollars-10,990 dollars for Indians, and 2597 dollars-17,879 dollars for other ethnic patients. In contrast, the indirect costs ranged from 1215 dollars to 3834 dollars for Chinese, 1138 dollars-6116 dollars for Malays, and 1371 dollars-5292 dollars for Indians. However, most ethnic variations were not statistically significant. CONCLUSION: The economic burden of OA to society and patients increased by 3-fold or more in the patients with TKR/THR compared to those without. The ethnic differences in health resources consumed were more apparent when the disease progressed.

Thirty-day mortality and morbidity after total knee arthroplasty.

INTRODUCTION: Total knee arthroplasty (TKA) is one of the most successful orthopaedic procedures to date. It is estimated that over 130,000 of TKAs are performed in the United States every year. Whilst the procedure is safe, it nevertheless carries a risk of perioperative mortality and morbidity. This study aimed to report the mortality rate within 30 days after a TKA, as well as to assess the incidence of early postoperative morbidities. MATERIALS AND METHODS: We reviewed a total of 2219 TKAs performed by multiple surgeons in our centre from 1998 to 2001. All mortalities within 30 days of a TKA were recorded. Morbidities such as infection, thromboembolic phenomenon, and any re-admissions within 30 days of operation or 15 days of discharge were recorded. RESULTS: The mortality rate within 30 days of a TKA was 0.27% (6 of 2219 patients). The incidence of early postoperative infection was 1.8%, of which 1.44% were superficial and 0.36% were deep infections. There were 3 cases (0.13%) of pulmonary embolism and 22 cases (0.99%) of deep vein thrombosis. CONCLUSIONS: The 30-day mortality rate, and the incidence of infection after TKA performed in our institution is comparable to other centres around the world, and further emphasises that TKA is a safe procedure. However, the small number of mortalities in this study does not allow us to identify a predominant cause of perioperative mortality.

Randomized control trial comparing radiographic total knee arthroplasty implant placement using computer navigation versus conventional technique.

The aim of this study is to assess the radiological outcome of conventional techniques versus computer-navigated surgery for total knee arthroplasty. Ninety patients with knee arthritis were prospectively randomized into 3 groups: conventional technique: extramedullary (EM) and intramedullary (IM) tibia guide versus computer navigation surgery (CAS). Two surgeons performed all procedures. Standardized long leg coronal and sagittal x-rays were evaluated by a blinded assessor. Our results showed that CAS had greater consistency and accuracy in implant placement. In the coronal view, 93.3% in the CAS group had better outcomes compared with EM (73.4%) and IM (60.0%). In the sagittal axis, 90.0% CAS also had better outcomes compared with EM (63.3%) and IM (76.7%). Computer-navigated total knee arthroplasty helps increase accuracy and reduce "outliers" for implant placement.

Stress fracture of the medial tibial plateau after minimally invasive unicompartmental knee arthroplasty: a report of 2 cases.

Minimally invasive unicompartmental knee arthroplasty has been increasingly popular for the past few years. Several short- and medium-term published reports have shown it to be as efficacious as open unicompartmental knee arthroplasty, with reduced morbidity. However, complications specifically related to the minimally invasive techniques are not well documented. We report 2 cases of stress fracture of the medial tibial plateau after unicompartmental knee arthroplasty with minimally invasive instrumentation. Awareness of this as a possible complication, with increased care in surgical technique, will help to avoid this problem.

Isolated congenital pseudoarthrosis of the fibula.

Congenital pseudarthrosis of the limb most commonly involves the tibia, although various combinations of bones including fibula, radius, ulna, clavicle and humerus have all been described. Isolated congenital pseudarthrosis of the fibula is a very rare entity with only 12 cases reported in the English literature. We report three cases of this condition treated in our institution. The first child had a varus ankle deformity at the age of 4 months. The other two children presented with valgus ankle deformity after they started to walk. Two patients were treated conservatively while the third had a distal tibio-fibular fusion in view of severe valgus deformity. All three patients showed good early results after 1 to 2 years. We advocate early distal tibio-fibular fusion to prevent valgus deformity in these children.