Sex differences in patellar facet shape among healthy and osteoarthritic cohorts.

OBJECTIVE: Patellofemoral osteoarthritis (OA) may be more common in females than males. Reasons for this are not fully understood, but sex differences in patellar morphology may help explain this phenomenon. We quantified differences in patellar morphology between males and females in healthy and patellofemoral OA populations. DESIGN: A total of 97 (50F, 47M) healthy and 67 (40F, 27M) OA knees were scanned via computed tomography. OA individuals were on a waitlist for total knee replacement. Patella 3D models were segmented and 2D measurements were recorded: patellar width and height, lateral and medial facet width, and surface area. Medial and lateral facet surface topography was mapped using 81 points to describe 3D articular surface shape. Sex and group differences were assessed using Procrustes analysis of variance (ANOVA). Data were ordinated using Principal Component Analysis. RESULTS: Differences in patellar 2D measurements between healthy and OA individuals were smaller than were differences between males and females from healthy and OA groups. Sex and healthy/OA differences were most pronounced for medial facet shape, which featured a posteriorly-curving facet and taller, narrower facet shape in males compared to females. Lateral facet shape variance was higher in OA cohorts compared to healthy groups. CONCLUSIONS: Medial and lateral facet shapes showed different patterning of variation by sex and healthy/OA status. Lateral facet shape may be of interest in future models of OA risk in the patellofemoral joint, here showing increased magnitudes of variance associated with increased severity of disease (patellofemoral Kellgren and Lawrence score).

Are Kinematics an Indicator of Outcome After Total Knee Arthroplasty?

BACKGROUND: A proportion of total knee arthroplasty (TKA) patients are dissatisfied postoperatively, particularly with their ability to perform higher-demand activities including deep-kneeling and step-up where kinematic parameters are more demanding. The purpose of this study was to examine the relationship between knee kinematics of step-up and deep-kneeling and patient-reported outcome measures following TKA. METHODS: Sixty-four patients were included at minimum 1-year follow-up. Participants performed a step-up and deep-kneeling task which was imaged via single-plane fluoroscopy. 3-dimensional prosthesis computer-aided design models were registered to the fluoroscopy, yielding in-vivo kinematic data. Associations between kinematics and patient-reported outcome measures, including Oxford Knee Score, American Knee Society Score, surgical satisfaction, and pain were assessed using log-transformed step-wise linear regressions. RESULTS: A higher total Oxford Knee Score was associated with more external rotation and more adduction at maximal flexion during kneeling and more external rotation and minimum flexion during step-up. Improved American Knee Society Score was associated with increased internal-external rotation during step-up. Improved surgical satisfaction was associated with greater maximum flexion and more external rotation at maximal flexion during deep-kneeling and more femoral internal rotation at terminal extension during step-up. An improved pain score was associated with greater maximum flexion and more femoral external rotation during deep-kneeling, as well as greater internal femoral rotation during step-up. CONCLUSION: The ability to move through full flexion/extension range and end-of-range rotation is important kinematic parameters that influence patient-reported outcome measures. Implant designs and postoperative rehabilitation should continue to focus on achieving these kinematic targets for enhanced outcomes after TKA.

Antibiotic utilisation in primary and revision total hip replacement patients: A registry linkage cohort study of 106 253 patients using the Australian Orthopaedic Association National Joint Replacement Registry.

PURPOSE: Infection is a major complication following joint replacement (JR) surgery. However, little data exist regarding antibiotic utilisation following primary JR and how use changes with subsequent revision surgery. This study aimed to examine variation in antibiotic utilisation rates before and after hip replacement surgery in those revised for infection, revised for other reasons and those without revision. METHODS: This retrospective cohort analysis used linked data from the Australian Orthopaedic Association National Joint Replacement Registry and Australian Government Pharmaceutical Benefits Scheme. Patients were included if undergoing total hip replacement (THR) for osteoarthritis in private hospitals between 2002 and 2017. Three groups were examined: primary THR with no subsequent revision (n = 102 577), primary THR with a subsequent revision for reasons other than periprosthetic joint infection (PJI) (n = 3156) and primary THR with a subsequent revision for PJI (n = 520). Monthly antibiotic utilisation rates and prevalence rate ratios (PRRs) with 95% confidence intervals (CIs) were calculated in the 2 years pre- and post-THR. RESULTS: Prior to primary THR antibiotic utilisation was 9%-10%. After primary THR, antibiotic utilisation rates were higher among patients revised for PJI (PRR 1.69, 95% CI 1.60-1.79) compared to non-revised patients, while the utilisation rate was lower in patients revised for reasons other than infection (PRR 0.96, 95% CI 0.93-0.98). For those revised for infection, antibiotic utilisation post-revision surgery was two times higher than those revised for other reasons (PRR 2.16, 95% CI 2.08-2.23). Utilisation of injectable antibiotics including, vancomycin, flucloxacillin and cephazolin was higher in those revised for PJI patients 0-2 weeks following surgery but not in those revised for other reasons compared to the non-revised group. CONCLUSIONS: Ongoing antibiotic utilisation after primary surgery may be an early signal of problems with the THR and should be a prompt for primary care physicians to refer patients to specialists for further appropriate investigations and management.

Diabetes mellitus is a potential risk factor for aseptic loosening around hip and knee arthroplasty.

BACKGROUND: Aseptic loosening is a leading cause of revision following total hip and knee arthroplasty which is caused by chronic inflammation around the prosthesis. Diabetes mellitus causes systemic inflammatory changes which could increase the risk of aseptic loosening. This study investigated the association between diabetes mellitus and aseptic loosening around hip and knee arthroplasty. METHODS: A case-control study was conducted at a single arthroplasty centre over the seven-year period of January 2015 to December 2021. Cases were defined as any adult patient undergoing revision hip or knee arthroplasty for aseptic loosening. Controls were randomly selected patients undergoing primary total hip or knee arthroplasty during the same period at a 1:4 ratio. Risk factors were compared between the two groups. RESULTS: A total of 440 patients were included in our study - 88 in the aseptic loosening group and 352 patients in the control group. The odds of having diabetes mellitus in the aseptic loosening group was 2.78 (95%CI 1.31-5.92, P = 0.01). Other risk factors were not significantly different between the two groups. CONCLUSIONS: The incidence of diabetes mellitus is significantly greater in patients undergoing revision arthroplasty for aseptic loosening. Further research is required to explore whether this association is indeed causative.

Union and Complication Rates After Total Wrist Arthrodesis: A Systematic Review and Meta-Analysis.

PURPOSE: Total wrist arthrodesis (TWA) has been performed using various techniques. We aimed to provide pooled prevalence estimates of union and complications of TWA by technique. A secondary aim was to provide estimates of union and complication rates by treatment of the carpometacarpal joint (CMCJ) in TWA using plates. Given the widespread adoption of wrist arthrodesis plates (WAP), we hypothesized that these implants would result in higher union and lower complication rates. We also hypothesized that TWA with CMCJ arthrodesis would improve these outcomes. METHODS: Online databases including PubMed, Medline, Embase, and Cochrane were searched. Studies reporting union and/or complication rates of 10 or more TWA performed with a similar technique (analyzed as bone graft only, bone graft with minimal fixation, intramedullary, augmented intramedullary, plate, WAP, and other) were included. Studies with fewer than 10 TWA, studies reporting TWA where union or complications could not be analyzed separately, and studies without union and complication rates were excluded. Data extraction was performed independently by two English-speaking reviewers with a translator where required. Pooled prevalence estimates were made using a random-effects meta-analysis model and presented as a percent prevalence with 95% confidence and prediction intervals. RESULTS: One hundred and thirty-six studies with a total of 3,517 patients and 3,969 TWA were analyzed. No differences in union and complication prevalence were observed between TWA techniques and in TWA with different treatments of the CMCJ using plates and WAP. CONCLUSION: Using meta-analysis, we found no difference in union and complication prevalence between TWA techniques and TWA with different treatments of the CMCJ with plates and WAP. It must be acknowledged that this research included low-quality studies with high heterogeneity, and confidence in the precision of the estimates is low. TYPE OF STUDY/LEVEL OF EVIDENCE: Prognostic IV.

Recommendations in the rehabilitation of patients undergoing hip abductor tendon repair: a systematic literature search and evidence based rehabilitation protocol.

INTRODUCTION: Advanced hip imaging and surgical findings have demonstrated that a common cause of greater trochanteric pain syndrome (GTPS) is hip abductor tendon (HAT) tears. Traditionally, these patients have been managed non-operatively, often with temporary pain relief. More recently, there has been an increase in published work presenting the results of surgical intervention. A variety of open and endoscopic transtendinous, transosseous and/or bone anchored suture surgical techniques have been reported, with and without the use of tendon augmentation for repair reinforcement. While patient outcomes have demonstrated improvements in pain, symptoms and function, post-operative rehabilitation guidelines are often vague and underreported, providing no guidance to therapists. MATERIALS AND METHODS: A systematic search of the literature was initially undertaken to identify published clinical studies on patients undergoing HAT repair, over a 3-year period up until May 2020. Following the application of strict inclusion and exclusion criteria, studies were identified and the detail relevant to rehabilitation was synthesized and presented. Published detail was combined with the authors clinical experience, with a detailed overview of rehabilitation proposed for this patient cohort. RESULTS: A total of 17 studies were included, reporting varied detail on components of rehabilitation including post-operative weight bearing (WB) restrictions, the initiation of passive/active hip range of motion (ROM) and resistance exercises. A detailed rehabilitation guide is proposed. CONCLUSION: In combining the current published literature on rehabilitation after HAT repair and our own clinical experience in the surgical management and post-operative rehabilitation of these patients, we present an evidence-based, structured rehabilitation protocol to better assist surgeons and therapists in treating these patients. This rehabilitation protocol has been implemented for several years through our institutions with encouraging published clinical outcomes.

A critical analysis of the 8th edition TNM staging for head and neck cutaneous squamous cell carcinoma with lymph node metastases and comparison to N1S3 stage and ITEM risk score: A multicenter study.

BACKGROUND AND OBJECTIVES: We performed a critical analysis of the 8th edition American Joint Committee on Cancer (AJCC) staging for head and neck cutaneous squamous cell carcinoma (HNcSCC) with nodal metastases and compared the performance to the N1S3 and ITEM systems. METHODS: Multicenter study of 990 patients with metastatic HNcSCC treated with curative intent. The end points of interest were disease-specific (DSS) and overall survival (OS). Model fit was evaluated using Harrell's Concordance Index (C-index), proportion of variation explained (PVE), Akaike information criterion, and Bayesian information criterion. RESULTS: N1S3 and ITEM demonstrated good distribution into risk categories in contrast to the AJCC system, which classified the majority (90.6%) of patients as N2-3 and Stage IV due to the high rate of extranodal extension. The N2c and N3a categories appeared redundant. There was considerable discordance between systems in risk allocation on an individual patient basis. N1S3 was the best performed (DSS: C-index 0.62, PVE 10.9%; OS: C-index 0.59, PVE 4.5%), albeit with relatively poor predictive value. CONCLUSIONS: The AJCC N category and tumor node metastasis stage have poor patient distribution and predictive performance in HNcSCC. The AJCC stage, N1S3, and ITEM score all provide limited prognostic information based on objective measures highlighting the need to develop a staging system specific to HNcSCC.

Total wrist arthrodesis with and without arthrodesis of the carpoMetacarpal joint (WAWWAM): study protocol.

BACKGROUND: It is controversial whether or not the carpometacarpal joint (CMCJ) should be included in total wrist arthrodesis (TWA). Complications commonly occur at this site and studies examining its inclusion and exclusion are conflicting. A randomised clinical trial comparing wrist arthrodesis with CMCJ arthrodesis and spanning plate to wrist arthrodesis with CMCJ preservation and non-CMCJ spanning plate has not been performed. METHOD: A single centre randomised clinical trial including 120 adults with end-stage isolated wrist arthritis will be performed to compare TWA with and without the CMCJ included in the arthrodesis. The primary outcome is complications in the first post-operative year. Secondary outcomes are Disabilities of the Arm, Shoulder and Hand (DASH) score, Patient Rated Wrist Evaluation (PRWE) and grip strength measured at 1, 2 and 5 years. Late complications, return to work and satisfaction will also be recorded. DISCUSSION: It is unknown whether the CMCJ should be included in TWA. This trial will contribute to an improved understanding of optimal management of the CMCJ in total wrist arthrodesis. TRIAL REGISTRATION: This trial was prospectively registered with the Australia New Zealand Clinical Trials Registry with identifying number ACTRN12621000169842 on the 16th February 2021. WHO: U1111-12626523. ANZCTR: ACTRN12621000169842.

Influence of component design on in vivo tibiofemoral contact patterns during kneeling after total knee arthroplasty: a systematic review and meta-analysis.

PURPOSE: Modern TKR prostheses are designed to restore healthy kinematics including high flexion. Kneeling is a demanding high-flexion activity. There have been many studies of kneeling kinematics using a plethora of implant designs but no comprehensive comparisons. Visualisation of contact patterns allows for quantification and comparison of knee kinematics. The aim of this systematic review was to determine whether there are any differences in the kinematics of kneeling as a function of TKR design. METHODS: A search of the published literature identified 26 articles which were assessed for methodologic quality using the MINORS instrument. Contact patterns for different implant designs were compared at 90° and maximal flexion using quality-effects meta-analysis models. RESULTS: Twenty-five different implants using six designs were reported. Most of the included studies had small-sample sizes, were non-consecutive, and did not have a direct comparison group. Only posterior-stabilised fixed-bearing and cruciate-retaining fixed-bearing designs had data for more than 200 participants. Meta-analyses revealed that bicruciate-stabilised fixed-bearing designs appeared to achieve more flexion and the cruciate-retaining rotating-platform design achieved the least, but both included single studies only. All designs demonstrated posterior-femoral translation and external rotation in kneeling, but posterior-stabilised designs were more posterior at maximal flexion when compared to cruciate retaining. However, the heterogeneity of the mean estimates was substantial, and therefore, firm conclusions about relative behaviour cannot be drawn. CONCLUSION: The high heterogeneity may be due to a combination of variability in the kneeling activity and variations in implant geometry within each design category. There remains a need for a high-quality prospective comparative studies to directly compare designs using a common method. LEVEL OF EVIDENCE: Systematic review and meta-analysis Level IV.

Musculoskeletal Injury in Paddle Sport Athletes.

INTRODUCTION: Kayak racing has been an Olympic sport since 1936. The sport is evolving with the introduction of ocean skis and stand-up-paddle boards (SUP). Musculoskeletal injury incidence surveys have been conducted for ultra-marathon events, but no data have been published for other racing formats. OBJECTIVE: To identify and compare the rates and types of injuries sustained by paddling athletes as a function of discipline and training parameters in Sprint, Marathon, Ultra-Marathon, and Ocean events. METHODS: Competitors from 6 kayak and/or ocean surf-ski races in Australia were surveyed. Before each race, competitors were asked to complete a questionnaire. The questionnaire investigated paddling-related injuries over the previous 5 years, athlete morphology, flexibility, equipment and its setup, training volume, and environment. RESULTS: Five hundred eighty-three competitors were surveyed. Disciplines included 173 racing-kayak (K1), 202 touring-kayak, 146 ocean-skis, 42 SUP, and 20 other. The top 5 paddling-related injuries were shoulder (31%), low back (23.5%), wrist (16.5%), neck (13.7%), and elbow (11.0%). The highest percentage of injury was found in K1 paddlers for shoulder (40.5%), SUP for low back (33.3%), and ocean-ski for wrist (22.6%). After controlling for on-water training hours, the relative risk (RR) of wrist injury was significantly increased in ocean-ski paddlers (1.86) and in paddlers with decreased flexibility (1.53-1.83). Relative risk of shoulder and low-back injury was significantly increased in athletes with lower training volumes (1.82-2.07). Younger athletes had lower RR of wrist and shoulder injury (0.58-0.62).

Total volume of cam deformity alone predicts outcome in arthroscopy for femoroacetabular impingement.

PURPOSE: Rates for arthroscopic surgery for femoroacetabular impingement (FAI) are rising and there is growing concern related to the effectiveness and costs associated with this treatment. There is a general lack of consensus as to the criteria for surgical selection of patients. The purpose of this study was to determine whether patient outcome following arthroscopic surgery for FAI could be predicted based on the size and location of deformity. The specific questions were: (1) what is the morphology of FAI in terms of size and location of deformity in a cohort of patients selected for surgery? (2) Do morphological factors predict postoperative improvement in hip scores? (3) Do morphological factors predict preoperative hip scores? (4) Are there clusters of morphological factors which explain postsurgical improvement in hip scores? MATERIALS AND METHODS: Computer tomography (CT) surgical plans of 90 hips in 79 patients who had undergone primary hip arthroscopy for FAI were retrospectively reviewed. Four parameters for the femur and acetabulum were created: total depth of deformity, maximal depth, extent and the position of maximal deformity. This data were compared with prospectively acquired preoperative and postoperative patient outcome data using generalised linear models. RESULTS: The cohort comprised 33 males and 46 females aged 37.9 (18-61). The majority (74%) had mixed morphology, 23% isolated cam, and 3% isolated pincer. Overall, the bone depth was greatest and more extensive on the femur. Increased total additional cam deformity alone predicted poorer postoperative outcome (p = 0.045). None of the morphological factors were related to preoperative scores and there was no association between the meta-variables and postoperative outcome. CONCLUSIONS: The results of this study indicate that a greater total volume of cam deformity led to poorer postoperative patient outcome scores at 1 year. This information provides the surgeon with more accurate patient-specific data for prediction of expected outcomes. LEVEL OF EVIDENCE: Level III diagnostic.

Image intensifier distortion influences a surgeon's ability to aim guidewires during orthopaedic procedures.

OBJECTIVE: Accurate insertion of a guidewire under image intensifier guidance is a fundamental skill required by orthopaedic surgeons. This study investigated how image intensifier distortion, which is composed of pin-cushion and sigmoidal components, changed the apparent trajectory of a guidewire, and the resulting deviation between the intended and actual guidewire tip position. MATERIALS AND METHODS: Intraoperative image intensifier images for 220 consecutive patients with hip fractures were retrospectively corrected for distortion using a global polynomial method. The deviation between the intended and actual guidewire tip positions was calculated. Additional distortion parameters were tested using an image intensifier produced by a different manufacturer, and a flat-panel c-arm. RESULTS: Deviation was approximately 1 cm if the guidewire was aimed from the extremity of the image and almost 0 if the entry point was only 20% from the centre (p < 0.001). The direction of deviation was different for left and right hips, with average deviations measuring 3 mm proximal and 5 mm distal respectively (p < 0.001). The flat-panel c-arm almost completely eliminated distortion. CONCLUSIONS: Image intensifier distortion significantly altered the intended trajectory of a guidewire, with guidewires aimed from the image periphery more affected than guidewires aimed from the centre. Furthermore, for right hips, guidewires should be aimed distal to their intended position, and for left hips they should be aimed proximal to achieve their desired position. The flat-panel c-arm eliminated the effect of distortion; hence, it may be preferable if precision in guidewire positioning is vital.

Bone Turnover Status: Classification Model and Clinical Implications.

Aim: To develop a practical model for classification bone turnover status and evaluate its clinical usefulness. Methods: Our classification of bone turnover status is based on internationally recommended biomarkers of both bone formation (N-terminal propeptide of type1 procollagen, P1NP) and bone resorption (beta C-terminal cross-linked telopeptide of type I collagen, bCTX), using the cutoffs proposed as therapeutic targets. The relationships between turnover subtypes and clinical characteristic were assessed in1223 hospitalised orthogeriatric patients (846 women, 377 men; mean age 78.1±9.50 years): 451(36.9%) subjects with hip fracture (HF), 396(32.4%) with other non-vertebral (non-HF) fractures (HF) and 376 (30.7%) patients without fractures. Resalts: Six subtypes of bone turnover status were identified: 1 - normal turnover (P1NP>32 µg/L, bCTX≤0.250 µg/L and P1NP/bCTX>100.0[(median value]); 2- low bone formation (P1NP ≤32 µg/L), normal bone resorption (bCTX≤0.250 µg/L) and P1NP/bCTX>100.0 (subtype2A) or P1NP/bCTX<100.0 (subtype 2B); 3- low bone formation, high bone resorption (bCTX>0.250 µg/L) and P1NP/bCTX<100.0; 4- high bone turnover (both markers elevated ) and P1NP/bCTX>100.0 (subtype 4A) or P1NP/bCTX<100.0 (subtype 4B). Compared to subtypes 1 and 2A, subtype 2B was strongly associated with nonvertebral fractures (odds ratio [OR] 2.0), especially HF (OR 3.2), age>75 years and hyperparathyroidism. Hypoalbuminaemia and not using osteoporotic therapy were two independent indicators common for subtypes 3, 4A and 4B; these three subtypes were associated with in-hospital mortality. Subtype 3 was associated with fractures (OR 1.7, for HF OR 2.4), age>75 years, chronic heart failure (CHF), anaemia, and history of malignancy, and predicted post-operative myocardial injury, high inflammatory response and length of hospital stay (LOS) above10 days. Subtype 4A was associated with chronic kidney disease (CKD), anaemia, history of malignancy and walking aids use and predicted LOS>20 days, but was not discriminative for fractures. Subtype 4B was associated with fractures (OR 2.1, for HF OR 2.5), age>75 years, CKD and indicated risks of myocardial injury, high inflammatory response and LOS>10 days. Conclusions: We proposed a classification model of bone turnover status and demonstrated that in orthogeriatric patients altered subtypes are closely related to presence of nonvertebral fractures, comorbidities and poorer in-hospital outcomes. However, further research is needed to establish optimal cut points of various biomarkers and improve the classification model.

Supervised or Unsupervised Rehabilitation After Total Hip Replacement Provides Similar Improvements for Patients: A Randomized Controlled Trial.

OBJECTIVE: To determine whether patients do better with unsupervised (home-based) physiotherapy or in an outpatient setting. SETTING: Acute care public hospital in the region, supporting a population of ∼540,000. DESIGN: Single-blind randomized controlled trial. PARTICIPANTS: Adult patients (N=98) after unilateral elective total hip replacement (THR) were randomly assigned to a supervised (center-based) exercise (n=56) or a unsupervised (home-based) exercise (n=42) program and followed for 6 months postsurgery. INTERVENTIONS: The supervised group attended a 4-week outpatient rehabilitation program supervised by a physiotherapist. The unsupervised group was given written and pictorial instructions to perform rehabilitation independently at home. MAIN OUTCOME MEASURES: Western Ontario and McMaster Universities Osteoarthritis Index; Short-Form 36-item Health Questionnaire (SF-36) mental and physical component summary measures; University of California, Los Angeles activity scale; and timed Up and Go test. RESULTS: There were no differences between the groups for any measure. The overall differences between the adjusted means were as follows: Western Ontario and McMaster Universities Osteoarthritis Index, 0.50 (95% confidence interval [CI], -6.8 to 5.7); SF-36 physical component summary, 0.8 (95% CI, -6.5 to 8.1); SF-36 mental component summary, 1.7 (95% CI, -4.1 to 7.4); University of California, Los Angeles activity scale, 0.3 (95% CI, 5.2 to 6.1); and timed Up and Go test, 0 seconds (95% CI, -1.4 to 1.3s). CONCLUSIONS: The results demonstrated that outcomes in response to rehabilitation after THR are clinically and statistically similar whether the program was supervised or not. The results suggest that early rehabilitation programs can be effectively delivered unsupervised in the home to low-risk patients discharged home after THR. However, the relative effect of late-stage rehabilitation was not tested.

Arthritogenic alphaviral infection perturbs osteoblast function and triggers pathologic bone loss.

Arthritogenic alphaviruses including Ross River virus (RRV), Sindbis virus, and chikungunya virus cause worldwide outbreaks of musculoskeletal disease. The ability of alphaviruses to induce bone pathologies remains poorly defined. Here we show that primary human osteoblasts (hOBs) can be productively infected by RRV. RRV-infected hOBs produced high levels of inflammatory cytokine including IL-6. The RANKL/OPG ratio was disrupted in the synovial fluid of RRV patients, and this was accompanied by an increase in serum Tartrate-resistant acid phosphatase 5b (TRAP5b) levels. Infection of bone cells with RRV was validated using an established RRV murine model. In wild-type mice, infectious virus was detected in the femur, tibia, patella, and foot, together with reduced bone volume in the tibial epiphysis and vertebrae detected by microcomputed tomographic (µCT) analysis. The RANKL/OPG ratio was also disrupted in mice infected with RRV; both this effect and the bone loss were blocked by treatment with an IL-6 neutralizing antibody. Collectively, these findings provide previously unidentified evidence that alphavirus infection induces bone loss and that OBs are capable of producing proinflammatory mediators during alphavirus-induced arthralgia. The perturbed RANKL/OPG ratio in RRV-infected OBs may therefore contribute to bone loss in alphavirus infection.

Total Knee Arthroplasty Using Bicruciate-Stabilized or Posterior-Stabilized Knee Implants Provided Comparable Outcomes at 2 Years: A Prospective, Multicenter, Randomized, Controlled, Clinical Trial of Patient Outcomes.

BACKGROUND: The bicruciate-stabilized (BCS) knee arthroplasty was developed to replicate normal knee kinematics. We examined the hypothesis that patients with osteoarthritis requiring total knee arthroplasty (TKA) will have better functional outcome and satisfaction with the BCS implant compared with an established posterior cruciate-stabilized implant. METHODS: This multicenter, randomized, controlled trial compared the clinical outcomes of a BCS implant against an established posterior cruciate-stabilized implant with 2-year follow-up. Of the patients awaiting primary knee arthroplasty for osteoarthritis, 228 were randomized to receive either a posterior-stabilized or BCS implant. Primary outcomes were knee flexion and Oxford Knee Score. Secondary outcomes were rate of complications and adverse events (AEs). Tertiary outcomes included Knee Society Score, University of California, Los Angeles, activity score, Patella scores, EQ-5D, 6-minute walk time, and patient satisfaction. RESULTS: Complete data were recorded for 98 posterior-stabilized implants and 97 BCS implants. Twelve patients had bilateral knee implants. There was no difference between the groups for any of the measures at either 1 or 2 years. At 2 years, knee flexion was 119 ± 0.16 and 120 ± 1.21 degrees for the posterior-stabilized and BCS implants, respectively, (mean, standard error, P = .538) and Oxford Knee Scores were 40.4 ± 0.69 and 40.0 ± 0.67 (P = .828), respectively. There were similar device-related AEs and revisions in each group (AEs 18 vs 22; P = .732; revisions 3 vs 4; P = .618). CONCLUSION: There was no evidence of clinical superiority of one implant over the other at 2 years.

Anatomic variations of levator scapulae in a normal cohort: an MRI study.

PURPOSE: Accessory attachments of the levator scapulae (LS) muscle have been described in the literature in previous cadaveric studies, but there is little knowledge about the incidence and distribution. Knowledge of LS accessory attachments is relevant to clinicians working in the fields of radiology, surgery, neurology, and musculoskeletal medicine. The purpose of this study was to explore the incidence and spectrum of LS caudal accessory attachments in vivo using magnetic resonance (MR) imaging in a young cohort. METHODS: MR images of the cervical spine were obtained from 37 subjects (13 males and 24 females) aged 18-36 years using an axial T1-weighted spin echo sequence acquired from a 3-Tesla MR scanner. The LS muscle was identified, and the presence of caudal accessory attachments was recorded and described. RESULTS: LS caudal accessory attachments were identified in 16 subjects (4 right, 6 left, and 6 bilateral; 12 female). Ten had unilateral accessory attachments to the serratus anterior, serratus posterior superior or the first/second rib. Four had bilateral accessory attachments to serratus anterior. One had bilateral accessory attachments to serratus posterior superior and unilateral accessory attachment to serratus anterior. One had bilateral attachments to both muscles. CONCLUSIONS: Both unilateral and bilateral LS caudal accessory attachments were present in nearly half of the subjects examined. They were relatively more frequent in females than males. The findings indicate that these accessory attachments are common, and in some cases, those accessory attachments can occur bilaterally and to more than one site.

Unexpected dependence of RyR1 splice variant expression in human lower limb muscles on fiber-type composition.

The skeletal muscle ryanodine receptor Ca(2+) release channel (RyR1), essential for excitation-contraction (EC) coupling, demonstrates a known developmentally regulated alternative splicing in the ASI region. We now find unexpectedly that the expression of the splice variants is closely related to fiber type in adult human lower limb muscles. We examined the distribution of myosin heavy chain isoforms and ASI splice variants in gluteus minimus, gluteus medius and vastus medialis from patients aged 45 to 85 years. There was a strong positive correlation between ASI(+)RyR1 and the percentage of type 2 fibers in the muscles (r = 0.725), and a correspondingly strong negative correlation between the percentages of ASI(+)RyR1 and percentage of type 1 fibers. When the type 2 fiber data were separated into type 2X and type 2A, the correlation with ASI(+)RyR1 was stronger in type 2X fibers (r = 0.781) than in type 2A fibers (r = 0.461). There was no significant correlation between age and either fiber-type composition or ASI(+)RyR1/ASI(-)RyR1 ratio. The results suggest that the reduced expression of ASI(-)RyR1 during development may reflect a reduction in type 1 fibers during development. Preferential expression of ASI(-) RyR1, having a higher gain of in Ca(2+) release during EC coupling than ASI(+)RyR1, may compensate for the reduced terminal cisternae volume, fewer junctional contacts and reduced charge movement in type 1 fibers.