Unilateral Arthroplasty Research Articles

The prevalence of bilateral and ipsilateral radiographic osteoarthritis is high in White, Asian and Native Hawaiian/Pacific Islanders presenting for unilateral knee or hip arthroplasty.

It is estimated that one-third of patients presenting with unilateral joint pain have contralateral osteoarthritis (OA) at first presentation. Most studies have primarily examined White patient cohorts. The purpose of this study was to determine the prevalence of contralateral joint OA for patients presenting for unilateral total knee (TKA), unicompartmental knee (UKA) or total hip arthroplasty (THA) among Asian, Native Hawaiian/Pacific Islander and White patients. Bilateral radiographic reports at initial presentation of 2,312 subjects who underwent unilateral arthroplasties (332 UKAs, 933 TKAs and 1,047 THAs) were reviewed. The presence of contralateral OA was recorded and compared by racial group and type of arthroplasty performed. Parametric statistical analyses were performed to determine differences between groups. Multivariable analyses were completed for each arthroplasty group to determine the influence on the presence of contralateral OA, presented as odds ratios and 95% confidence intervals. Contralateral joint OA was present in 86.7%, 90.4% and 70.4% of UKA, TKA and THA patients, respectively. Concurrent hip OA was present in 41.6% and 59.5% of UKA and TKA patients. No racial differences in the prevalence of contralateral knee OA were found for knee arthroplasty patients. White patients (74.6%) had a greater prevalence of contralateral hip OA compared to Asians (66.5%, p = 0.037) amongst THA recipients. Increased age and body mass index were significantly associated with the presence of contralateral knee OA. Increased age, being male and being White were significant contributors for the presence of contralateral hip OA. The prevalence of contralateral joint OA and concurrent hip OA is high in all three racial groups. Due to the extensive prevalence of contralateral and concurrent knee and hip OA, bilateral radiographic evaluation should be considered for all patients presenting with unilateral hip or knee pain due to OA.

Role of the NeuroCuple™ Device for the Postoperative Pain Management of Patients Undergoing Unilateral Primary Total Knee and Hip Arthroplasty: A Pilot Prospective, Randomized, Open-Label Study

Background: The potential effectiveness of the non-pharmacological and nanotechnology-based NeuroCuple™ device in reducing postoperative surgical pain and opioid consumption remains unknown. Methods: This randomized controlled open-label study was conducted in patients undergoing a primary unilateral total knee or total hip arthroplasty. In the recovery room, patients were randomized to receive either standard of care (control group) or standard of care plus two NeuroCuple™ devices. The outcome variables included pain and opioid consumption (oral morphine equivalent, OME in milligrams). Results: A total of 69 patients were randomized to either the NeuroCuple™ group (n = 38) or the control group (n = 31). Use of the NeuroCuple™ devices was associated with a significant 34% reduction in pain at rest (means of area under the curve: 6.3 vs. 9.5; p = 0.018) during postoperative days 1–3. Opioid consumption was reduced by 9%. More importantly, use of the NeuroCuple™ devices reduced the number of patients requesting an opioid prescription following discharge from the hospital by 52% (26% vs. 55%, p = 0.016). Conclusions: Our data suggest that the NeuroCuple™ device may be an effective non-pharmacological alternative to opioids to manage postoperative pain following unilateral arthroplasty due to its ability to reduce postoperative opioid use.

Transition to Anterior Approach in Primary Total Hip Arthroplasty - Learning Curve Complications

Introduction: The recent emphasis on tissue preservation and minimally invasive outpatient joint replacements has resulted in a significant increase in the use of Direct Anterior Approach (DAA) total hip arthroplasty. It has gained interest recently because of its faster short-term recovery, despite concerns about increased complications and operative time, especially during the learning curve period. The primary objective of this study was to determine whether complications of transitioning to a direct anterior approach for primary total hip arthroplasty may impair patient safety. Methods: A total of 51 primary hip arthroplasties were performed in 44 patients with the direct anterior approach technique: 37 unilateral arthroplasties and 7 bilateral arthroplasties, during the first 3 years of the learning curve of this technique and their complications were analyzed. Results: No patient had severe complications or surgical reinterventions associated to transoperative complications. Tearing of the tensor fascia lata muscle was on average the most frequent complication (19.6%), followed by skin lesions (17.6%), difficulty in implant reduction (9.8%) and fractures of the greater trochanter (7.8%). No severe complications occurred. Conclusion: This study demonstrates that the transition to the direct anterior approach can be done safely without a significant complication rate. These complications are usually associated with the use of inadequate special instruments, inadequate patient selection and the knowledge of maneuvers of the surgeon and his team acquired during the experience and development of the technique. Even so, they do not require additional treatment, which allows us to conclude that this technique is reproducible and can be safely transitioned.

MACHINE LEARNING PREDICTION AND OPTIMIZATION IMPROVES ELECTIVE ORTHOPAEDIC SURGERY SCHEDULING

Total knee and hip arthroplasty (TKA and THA) are the most commonly performed surgical procedures, the costs of which constitute a significant healthcare burden. Improving access to care for THA/TKA requires better efficiency. It is hypothesized that this may be possible through a two-stage approach that utilizes prediction of surgical time to enable optimization of operating room (OR) schedules.Data from 499,432 elective unilateral arthroplasty procedures, including 302,490 TKAs, and 196,942 THAs, performed from 2014-2019 was extracted from the American College of Surgeons (ACS) National Surgical and Quality Improvement (NSQIP) database. A deep multilayer perceptron model was trained to predict duration of surgery (DOS) based on pre-operative clinical and biochemical patient factors. A two-stage approach, utilizing predicted DOS from a held out “test” dataset, was utilized to inform the daily OR schedule. The objective function of the optimization was the total OR utilization, with a penalty for overtime. The scheduling problem and constraints were simulated based on a high-volume elective arthroplasty centre in Canada. This approach was compared to current patient scheduling based on mean procedure DOS. Approaches were compared by performing 1000 simulated OR schedules.The predict then optimize approach achieved an 18% increase in OR utilization over the mean regressor. The two-stage approach reduced overtime by 25-minutes per OR day, however it created a 7-minute increase in underutilization. Better objective value was seen in 85.1% of the simulations.With deep learning prediction and mathematical optimization of patient scheduling it is possible to improve overall OR utilization compared to typical scheduling practices. Maximizing utilization of existing healthcare resources can, in limited resource environments, improve patient's access to arthritis care by increasing patient throughput, reducing surgical wait times and in the immediate future, help clear the backlog associated with the COVID-19 pandemic.

Determinants of Complex Regional Pain Syndrome Type I among Radial Head Fracture Patients with Unilateral Arthroplasty.

ObjectiveThis study aims to assess the proportions of complex regional pain syndrome type I (CRPS I) in radial head fracture patients undergoing unilateral arthroplasty and to explore associated factors.MethodsThis is a prospective observational study. From March 2016 to May 2019, a total of 221 adult patients with radial head fracture patients were included in consecutive studies and completed the 1‐year follow‐up. All patients were treated by unilateral arthroplasty. At each follow‐up visit, the visual analogue scale was used to measure patients' pain level. Occurrence of CRPS I, which was diagnosed by Budapest criteria, was the main outcome collected at baseline and the 1‐, 3‐, 6‐, and 9‐month follow‐ups. The baseline data were collected before surgery and included demographic and clinical data. Independent t‐tests and χ 2 tests were used as univariate analyses to compare the baseline data of patients with and without CRPS I. Multivariate analysis (Backword‐Wald) was used to identify factors independently associated with CRPS I.ResultsThe proportion of CRPS I cases among radial head fracture patients undergoing unilateral arthroplasty was 11% (n = 24). A total of 19 (79%) patients were diagnosed with CRPS I within 1 month after surgery. Multivariable logistic regression analysis revealed that female gender (odds ratios [OR]: 1.537; 95% confidence interval [CI]: 1.138–2.072), age younger than 60 years (OR: 1.682; 95% CI: 1.246–2.267), moderate and severe Mayo Elbow Performance Score (MEPS) pain (OR: 3.229; 95% CI: 2.392–4.351) and anxiety (OR: 83.346; 95% CI: 61.752–112.320) were independently associated with CRPS I.ConclusionsThis exploratory study reported that the incidence of CRPS I developing after radial head arthroplasty was 11%. Female sex, younger age, moderate and severe MEPS pain and anxiety patients seems more likely to develop CRPS I.

Total, hemi, or dual-mobility arthroplasty for the treatment of femoral neck fractures in patients with neurological disease : analysis of 9,638 patients from the Swedish Hip Arthroplasty Register.

The aim of this study was to investigate the potentially increased risk of dislocation in patients with neurological disease who sustain a femoral neck fracture, as it is unclear whether they should undergo total hip arthroplasty (THA) or hemiarthroplasty (HA). A secondary aim was to investgate whether dual-mobility components confer a reduced risk of dislocation in these patients. We undertook a longitudinal cohort study linking the Swedish Hip Arthroplasty Register with the National Patient Register, including patients with a neurological disease presenting with a femoral neck fracture and treated with HA, a conventional THA (cTHA) with femoral head size of ≤ 32 mm, or a dual-mobility component THA (DMC-THA) between 2005 and 2014. The dislocation rate at one- and three-year revision, reoperation, and mortality rates were recorded. Cox multivariate regression models were fitted to calculate adjusted hazard ratios (HRs). A total of 9,638 patients with a neurological disease who also underwent unilateral arthroplasty for a femoral neck fracture were included in the study. The one-year dislocation rate was 3.7% after HA, 8.8% after cTHA < 32 mm), 5.9% after cTHA (= 32 mm), and 2.7% after DMC-THA. A higher risk of dislocation was associated with cTHA (< 32 mm) compared with HA (HR 1.90 (95% confidence interval (CI) 1.26 to 2.86); p = 0.002). There was no difference in the risk of dislocation with DMC-THA (HR 0.68 (95% CI 0.26 to 1.84); p = 0.451) or cTHA (= 32 mm) (HR 1.54 (95% CI 0.94 to 2.51); p = 0.083). There were no differences in the rate of reoperation and revision-free survival between the different types of prosthesis and sizes of femoral head. Patients with a neurological disease who sustain a femoral neck fracture have similar rates of dislocation after undergoing HA or DMC-THA. Most patients with a neurological disease are not eligible for THA and should thus undergo HA, whereas those eligible for THA could benefit from a DMC-THA. Cite this article: Bone Joint J2022;104-B(1):134-141.

Immortal Time Bias in the Analysis of Time-to-Event Data in Orthopedics

Many outcomes in arthroplasty research are analyzed as time-to-event outcomes using survival analysis methods. When comparison groups are defined after a time-delayed exposure or intervention, a period of immortal time arises and can lead to biased results. In orthopedics research, immortal time bias often arises when a minimum amount of follow-up is required for study inclusion or when comparing outcomes in staged bilateral vs unilateral arthroplasty patients. We present an explanation of immortal time and the associated bias, describe how to correctly account for it using proper data preparation and statistical techniques, and provide an illustrative example using real-world arthroplasty data. We offer practical guidelines for identifying and properly handling immortal time to avoid bias. Please visit the followinghttps://youtu.be/58p8w5o-ci4for a video that explains the highlights of the paper in practical terms.

One-stage bilateral total hip arthroplasty versus unilateral total hip arthroplasty: A retrospective case-matched study

BackgroundOne-stage bilateral hip replacement has the advantage of involving a single anesthesia, single hospital admission and single rehabilitation program. The theoretic drawback is increased surgical risk. Few French series have been reported, and none with comparison versus unilateral arthroplasty. We therefore conducted a comparative case-control study between 1-stage bilateral (1B-THA) and unilateral total hip arthroplasty (U-THA), assessing (1) morbidity/mortality, (2) survival, and (3) functional scores and forgotten hip rates. HypothesisIn a selected ASA 1 or 2 population, 1B-THA shows complications rates and implant survival comparable to U-THA. Material and methodBetween 2004 and 2018, 327 patients were included: 109 with 1B-THA, 218 with U-THA. One 1B-THA patient was matched to 2 U-THA patients on age, gender, diagnosis, ASA score 1 or 2, and anterior or posterior approach. Minimum follow-up was 12 months. Complications were collected for all patients in both groups. Early (≤90 days) or late (>90 days) morbidity/mortality and implant survival were recorded for both groups. Secondary endpoints concerned blood-sparing strategy and blood loss, functional scores, and patient satisfaction. ResultsMortality was zero in both groups. There was no significant difference in complications rates (1B-THA 38.5%, U-THA 40.8%) (p=0.69), whether early (8.3% [9/109] and 7.8% [17/218] respectively [p=0.89]) or late (30.3% [33/109] and 33.0% [72/218] respectively [p=0.61]). Limb-length discrepancy was significantly less frequent in 1B-THA (5.5% [6/109] versus 13.3% [29/218] [p=0.03]). Forgotten hip rate was significantly more frequent in 1B-THA (86% [94/109] versus 70% [152/218] [p=0.01]). Five-year Kaplan-Meier implant survival was 97.2% (95% CI [91.9–99.1]) in 1B-THA and 96.6% (95% CI [93.0–98.4]) in U-THA (p=0.08). DiscussionOne-stage bilateral total hip arthroplasty gave acceptable results in disabling bilateral osteoarthritis of the hip with low surgical risk in selected patients (ASA 1 or 2). Mortality, complications and implant survival were unaffected, but the 1-stage bilateral procedure allowed better control of limb-length and provided a higher rate of forgotten hip. Level of evidenceIII, matched case-control study.

Accuracy of Patient-Reported Preoperative Opioid Use and Impact on Continued Opioid Use After Outpatient Arthroplasty

BackgroundThe opioid epidemic has created a national healthcare crisis, and little is known about the accuracy of self-reported narcotic usage in arthroplasty. The purpose of this study is to evaluate the accuracy of self-reported opioid usage in patients undergoing outpatient arthroplasty. MethodsA retrospective review was conducted on all primary unilateral arthroplasty procedures performed in 2018 at a free-standing ambulatory surgery center, yielding a cohort of 959 arthroplasties. Patient’s prescription records were queried in the Ohio Automated Rx Reporting System for 3 months before surgery and minimum 9 months after surgery. These data were cross-referenced against the patient-reported preoperative use of narcotics. Three groups were evaluated: (G1) no preoperative narcotics, (G2) accurately self-reported on narcotics, and (G3) on narcotics but did not disclose. ResultsOne hundred fourteen patients (12%) were on preoperative opioids based on the Ohio Automated Rx Reporting System query, with only 35 of these patients (31%) self-reporting. G2 had significantly lower postoperative knee range of motion, Knee Society Pain score, Knee Society Clinical score, Knee Society Functional score, Harris Hip Score, and University of California Los Angeles activity scores than G1. Overnight stays occurred in 1.2% of patients in G1, 3% of patients in G2 (P = .5), and 6.3% of patient in G3 (P = .002). All aspects of postoperative narcotic use were significantly higher in G2 and G3 compared to G1. The relative risk for narcotic refill after 90 days in G2 was 4.6 (95% confidence interval 3.7-5.8, P < .001). ConclusionThe majority of patients on preoperative narcotics did not disclose their use. Patients on narcotics preoperatively had significantly greater postoperative narcotic use including refills, total morphine milliequivalent, and risk of being on narcotics 90 days after surgery.

Patient-reported activities after bilateral reverse total shoulder arthoplasties.

Reverse shoulder arthroplasty (RSA) improves pain and function with very good satisfaction. Concerns exist about some activities of daily living (ADLs) involving internal rotation. The purpose of this study was to report how patients with bilateral RSA perform various ADLs. Thirty-one primary bilateral RSA patients (average age 76 years; 21 women and 10 men) completed a survey to assess various outcomes. The average time between the second arthroplasty and the survey was 2.7 years (range 1.0-7.8 years). All clinical parameters were favorable. All patients reported being able to easily manage toileting and 87% reaching their back pocket. However, 29% found difficulty and 39% were unable to wash their back or put on bra. In comparison with various unilateral arthroplasty types, there was no statistical difference in overall activities ( p < 0.05). Bilateral RSA can provide good functional outcome and high satisfaction. Patients manage most ADLs easily with some limitations in activities requiring extreme internal rotation.

The Natural History of Osteoarthritis: What Happens to the Other Hip?

Idiopathic osteoarthritis (OA) is a common diagnosis leading to hip arthroplasty. Patients undergoing unilateral hip arthroplasty often wonder whether their other hip will follow the same path as the one that was operated on, and if so, when? There also are limited data available to predict from AP radiographs which contralateral hips will have OA develop and which will not. We sought (1) to determine the incidence of contralateral osteoarthritic degeneration in a group of patients who were treated with unilateral hip arthroplasty; and (2) to identify clinical and radiographic features associated with the development of contralateral OA. Between 1998 and 2010, we performed 398 hip arthroplasties on patients with unilateral primary hip OA, who at the time of surgery did not have any symptoms in the contralateral hip. Of those, 367 (92%) had a minimum 2-year radiographic followup (mean, 11 years; range, 2-17 years). The 31 patients dropped from the study for lack of radiographic followup had comparable preoperative features as the study group. We performed a radiographic analysis on the baseline AP radiographs to see what factors were associated with arthritis progression, and we performed Kaplan-Meier survivorship analysis with contralateral hip pain and contralateral THA as the endpoints. Kaplan-Meier survival estimates indicated that 10 years after the baseline evaluation, 59% (95% CI, 53%-65%) of the patients remained free of symptoms on the contralateral hip and 81% (95% CI, 75%-85%) remained free of an arthroplasty on the contralateral hip. Sex, age, weight, or BMI were not associated with the development of OA on the contralateral hip with the numbers available. Reduced minimum joint space width (hazard ratio, 0.299; 95% CI, 0.237-0.378), low center-edge angle (hazard ratio, 0.941; 95% CI, 0.915-0.968), low head-to-neck ratio (hazard ratio, 1.555; 95% CI, 1.088-2.223), and the presence of osteophytes (hazard ratio, 1.453; 95% CI, 1.001-2.110) were associated with the development of contralateral OA. In hips with a center-edge angle greater than 25°, a head-to-neck ratio of 1.3 or less increased the chances of development of OA by 86% (hazard ratio, 1.857; 95% CI, 1.235-2.793). The variables we studied can easily be assessed from an AP pelvis radiograph so physicians can predict the occurrence of contralateral OA and the need for future hip arthroplasty in their patients needing unilateral arthroplasty. However, the data available might have led us to underestimate the need for contralateral arthroplasty. Future studies with a prospective design should aim at completing the list of radiographic features associated with the development of OA by adding a review of lateral radiographs. Level IV, prognostic study.

Tranexamic Acid Decreases Incidence of Blood Transfusion in Simultaneous Bilateral Total Knee Arthroplasty

Blood management for simultaneous bilateral total knee arthroplasty (TKA) patients is more challenging than in unilateral arthroplasty. We examined if administration of tranexamic acid (TXA) to patients undergoing simultaneous bilateral TKA would reduce blood loss and decrease allogeneic blood transfusion requirements. A retrospective review of 103 patients, 57 in the control and 46 in the TXA group, was performed. There was higher postoperative day 1 hemoglobin in patients receiving TXA (2.95±1.33 versus 4.33±1.19, P<0.0001). There was also a decrease in the transfusion incidence with administration of TXA (17.4% versus 57.9%, P<0.0001). In conclusion, we have shown that TXA is an effective tool in reducing the transfusion rates by almost 70% in simultaneous bilateral total knee arthroplasty.

Comparison of the impact of rivaroxaban and low molecular weight heparin on hidden blood loss after unilateral first half artificial hip replacement surgery

Objective To investigate the impact of rivaroxaban and low molecular weight heparin on hidden blood loss after unilateral first half artificial hip replacement surgery. Methods According to the digital table, a total of 80 cases because of femoral neck fractures in elderly patients with unilateral arthroplasty artificial hip and a half after surgery were randomly divided into the rivaroxaban group and low molecular weight heparin(LMWH)group,40 cases in each group. In both groups,respectively, after 12 h begin daily oral rivaroxaban 10 mg and subcutaneous low molecular weight heparin 5 000 u,compared the two groups around the actual amount of perioperative blood loss, blood loss was dominant, recessive blood loss and hidden blood loss accounts, the actual percentage of total blood loss, and recorded 35d bleeding events. Results The total amount of blood loss, dominant blood loss, hidden blood loss and the hidden blood loss accounted for the actual percentage of the total amount of blood loss of the rivaroxaban group were(671.00±55.61)mL,(313.88±14.53) mL,(350.00±29.41)mL,(52.00±5.22)%,respectively,which of the the LMWH group were(662.00±30.19)mL,(288.87±15.33)mL,(372.00±35.10)mL,(56.00±6.71)%,there were no significant differences between the two groups(t= 0.93,0.93,0.83,1.03,all P>0.05). Conclusion For patients first underwent unilateral hip replacement surgery artificial half, perioperative using rivaroxaban or LMWH has no significantly differences in hidden risk of bleeding and bleeding event rate. Key words: Arthroplasty, Replacement, Hip; Postoperative Hemorrhage; Rivaroxaban; Low Molecular Weight Heparin

Changes of thrombelastography in patients undergoing elective primary total knee and total hip replacement with low molecular heparin prophylaxis.

BackgroundThere has been no effective method to monitor the changes of blood coagulation after thromboprophylaxis for elective arthroplasty patients. The objective of this study is to assess the coagulation status of patients undergoing arthroplasty with thromboelastograph (TEG).MethodsNinety patients undergoing primary elective unilateral arthroplasty were investigated. Thromboprophylaxis continued for at least 10 days. TEG was performed on the day before the operation and on postoperative days 1, 4, and 9.ResultsThe total hip and total knee groups showed significant changes in the distribution of different hypercoagulable states on days 1–4 and on days 4–9. On day 9 after operation, 34 out of 90 (37.8%) of the total hip and total knee patients were found with hypercoagulable state. Of these 34 patients with hypercoagulable state, 26 (76.5%) demonstrated platelet or mixed hypercoagulability.ConclusionsThrombelastography was an effective way to identify hypercoagulability in patients undergoing elective primary total knee and total hip replacement. Platelet may play an important role in the progress of blood hypercoagulability.

A Mobile Compression Device for Thrombosis Prevention in Hip and Knee Arthroplasty

Venous thromboembolic events, either deep venous thrombosis or pulmonary embolism, are important complications in patients undergoing knee or hip arthroplasty. The purpose of this study was to evaluate the effectiveness of a mobile compression device (ActiveCare+S.F.T.) with or without aspirin compared with current pharmacological protocols for prophylaxis against venous thromboembolism in patients undergoing elective primary unilateral arthroplasty of a lower-extremity joint. A multicenter registry was established to capture the rate of symptomatic venous thromboembolic events following primary knee arthroplasty (1551 patients) or hip arthroplasty (1509 patients) from ten sites. All patients were eighteen years of age or older with no known history of venous thromboembolism, coagulation disorder, or solid tumor. Use of the compression device began perioperatively and continued for a minimum of ten days. Patients with symptoms of deep venous thrombosis or pulmonary embolism underwent duplex ultrasonography and/or spiral computed tomography. All patients were evaluated at three months postoperatively to document any evidence of deep venous thrombosis or pulmonary embolism. Of 3060 patients, twenty-eight (0.92%) had venous thromboembolism (twenty distal deep venous thrombi, three proximal deep venous thrombi, and five pulmonary emboli). One death occurred, with no autopsy performed. Symptomatic venous thromboembolic rates observed in patients who had an arthroplasty of a lower-extremity joint using the mobile compression device were noninferior (not worse than), at a margin of 1.0%, to the rates reported for pharmacological prophylaxis, including warfarin, enoxaparin, rivaroxaban, and dabigatran, except in the knee arthroplasty group, in which the mobile compression device fell short of the rate reported for rivaroxaban by 0.06%. Use of the mobile compression device with or without aspirin for patients undergoing arthroplasty of a lower-extremity joint provides a noninferior risk for the development of venous thromboembolism compared with current pharmacological protocols.

The effect of the Oxford uncemented medial compartment arthroplasty on the bone mineral density and content of the proximal tibia

We studied the bone mineral density (BMD) and the bone mineral content (BMC) of the proximal tibia in patients with a well-functioning uncemented Oxford medial compartment arthroplasty using the Lunar iDXA bone densitometer. Our hypothesis was that there would be decreased BMD and BMC adjacent to the tibial base plate and increased BMD and BMC at the tip of the keel. There were 79 consecutive patients (33 men, 46 women) with a mean age of 65 years (44 to 84) with a minimum two-year follow-up (mean 2.6 years (2.0 to 5.0)) after unilateral arthroplasty, who were scanned using a validated standard protocol where seven regions of interest (ROI) were examined and compared with the contralateral normal knee. All had well-functioning knees with a mean Oxford knee score of 43 (14 to 48) and mean Knee Society function score of 90 (20 to 100), showing a correlation with the increasing scores and higher BMC and BMD values in ROI 2 in the non-implanted knee relative to the implanted knee (p = 0.013 and p = 0.015, respectively). The absolute and percentage changes in BMD and BMC were decreased in all ROIs in the implanted knee compared with the non-implanted knee, but this did not reach statistical significance. Bone loss was markedly less than reported losses with total knee replacement. There was no significant association with side, although there was a tendency for the BMC to decrease with age in men. The BMC was less in the implanted side relative to the non-implanted side in men compared with women in ROI 2 (p = 0.027), ROI 3 (p = 0.049) and ROI 4 (p = 0.029). The uncemented Oxford medial compartment arthroplasty appears to allow relative preservation of the BMC and BMD of the proximal tibia, suggesting that the implant acts more physiologically than total knee replacement. Peri-prosthetic bone loss is an important factor in assessing long-term implant stability and survival, and the results of this study are encouraging for the long-term outcome of this arthroplasty.

Postoperative complications following primary unilateral and simultaneous bilateral total knee arthroplasty

Objective To compare postoperative complications in patients firstly undergoing primary unilateral total knee arthroplasty (UTAK) and simultaneous bilateral total knee arthroplasty (SBTKA) .Methods From November 2006 to November 2009, 339 patients underwent primary UTAK and SBTKA in our hospital and followed up. The UTKA group had 178 patients (50 men and 128 women) who were aged from 26 to 81 years (mean, 64. 2 years) and a mean American Knee Society Score (KSS) of 34. 0 ± 13. 3points before surgery. The SBTKA group had 161 patients (32 men and 129 women) who were aged from 34 to 80 years (mean, 65. 3 years) and a mean KSS of 33. 4 ± 11. 1 points before surgery. The postoperative complications were compared between the 2 groups and clinical outcomes were evaluated according to KSS system. Results The patients were followed for 18. 4 months on average (range, 3 months to 3 years) . The incidence of postoperative complications was 6. 2% (11/178) in the UTKA group and 4. 3% (7/161) in the SBTKA group, with no significant difference (x2 =0. 564, P = 0. 453) . The KSS score at the final follow-up was all increased in both groups. It was 92. 5 ± 10. 6 in the UTKA group and 91. 9 ± 11. 1 in the SBTKA group, with no significant difference (t =0.511, P = 0.610). Conclusions SBTKA is not an independent risk factor for postoperative complications. Careful operative preparation and assessment, good surgical skills, comprehensive postoperative monitoring and supporting management, and proper rehabilitation can significantly reduce complications following SBTKA. But for a patient who has been complicated with multiple internal diseases, SBTKA decision should not be made before a careful tolerance assessment of the patient. Key words: Arthroplasty, replacement, knee; Postoperative complications

Dynamic hip joint stiffness in individuals with total hip arthroplasty: Relationships between hip impairments and dynamics of the other joints

Background Little is known about hip joint stiffness during walking (dynamic joint stiffness) and the effect of hip impairments on biomechanical alterations of other joints in patients with total hip arthroplasty. Methods Twenty-four patients (mean age 61.7 years) who underwent unilateral ( n = 12) or bilateral total hip arthroplasty ( n = 12) and healthy subjects ( n = 12) were recruited. In addition to kinematic and kinetic variables, dynamic hip joint stiffness which was calculated as an angular coefficient of linear regression of the plot of the hip flexion moment vs. hip extension angle during the late stance of gait, was measured. Group differences were compared using one-way ANOVA and Tukey's post-hoc test, and relationships between primary hip impairments and secondary gait impairments were found using partial correlation coefficients adjusted for gait speed and stride length. Findings Dynamic hip joint stiffness was 47% higher on the side with the more pronounced limp in patients with bilateral arthroplasty than in healthy controls. In the same patients, increased dynamic hip joint stiffness was significantly associated especially with increased ankle plantarflexion moment on the ipsilateral side. In patients with unilateral arthroplasty, decreased hip power was significantly related to increased ankle plantarflexor power, only on the non-operated side. Interpretation We found that dynamic hip joint stiffness was an important factor in assessing relationships between hip impairments and dynamics in other joints, especially in patients with bilateral total hip arthroplasty. The effects of altering hip joint stiffness on gait biomechanics need to be explored.

The comparison of the effects of intraoperative bleeding control and postoperative drain clamping methods on the postoperative blood loss and the need for transfusion following total knee arthroplasty

We aimed to determine and compare the effects of intraoperative bleeding control and two hours postoperative drain clamping method on postoperative wound drainage and the need for donor blood transfusion following total knee arthroplasty (TKA). Seventy-one patients who underwent TKA were randomly assigned into two groups. Fourty-four knees of 32 patients comprised Group A and 51 knees of 39 patients comprised Group B. In Group A, no bleeding control was done and postoperatively, the drain was clamped for 2 hours. Then it was unclamped to begin aspiration after the 2nd hour. In Group B, the bleeding was controlled intraoperatively, and the drain was not clamped after the surgery. Drains were removed 48 hours after the surgery in both groups. Bilateral and unilateral arthroplasty patients were evaluated separately. The groups were compared for their preoperative and postoperative 3-day haemoglobin (Hb) levels, total drainage amount and total number of blood transfusions. The haemoglobin levels were similar in both groups preoperatively and at the 1st, 2nd and 3rd postoperative days. In Group A, the wound drainage was 696.1±235.4 ml in unilateral TKA patients and was 1010.8±535.5 ml in bilateral arthroplasty patients. In Group B, the wound drainage was 710.1±380.1 ml in unilateral TKA patients and was 878.3±489.6 ml in bilateral arthroplasty patients. The mean number of transfusions was 1.41 units with no significant differences between the groups. The two hour drain clamping method without intraoperative bleeding control does not seem to affect the amount of blood loss and the need for transfusion when compared to intraoperative bleeding control in total knee arthroplasty patients. Hovewer, it is a simple and feasible method and can be used to decrease the operation time.

The effect of surgeon volume on the need for transfusion following primary unilateral hip and knee arthroplasty

Introduction We reviewed transfusion practice following primary hip and knee arthroplasty with emphasis on the relationship between surgeon volume and the need for transfusion. Materials/methods Review of a consecutive series of 508 primary, elective, unilateral arthroplasties (248 THR/260 TKR) performed over a 12-month period. Data were analysed to determine the overall rate of transfusion and the details of any such transfusion. Secondarily, multivariate regression was performed to determine the effects of surgeon volume and other recorded variables upon the need for transfusion. For the purpose of analysis we classified surgeons doing more than 52 arthroplasties a year as “high volume” and surgeons performing less than this number as “low volume”. Results Transfusion rates were 10% and 7% following THR and TKR. Multivariate analysis demonstrated that surgeon volume (<52 operations/yr vs. >52 operations/yr) and preoperative Hb<12 g/dl were the only significant determinants of a need for postoperative transfusion ( p < 0.01). High volume and low volume surgeons transfused 5% vs. 17%, respectively (RR = 3.3 (95%CI 1.5–9.1) p = 0.003) following THR and 4% vs. 13% (RR = 3.6 (95%CI 1.4–9.3) p = 0.006) following TKR. Discussion and conclusion High volume surgeons have significantly lower transfusion rates when compared to nationally accepted figures.