Do patients with osteoarthritis lose weight prior to elective joint replacement?

BACKGROUND: Obesity is a known risk factor for the development of osteoarthritis and the subsequent need for joint replacement. Weight loss has been shown to reduce pain, disability, and the need for joint replacement, particularly in patients with knee osteoarthritis. The aim of this study was to investigate pre-operative weight change in patients with hip, knee, and shoulder osteoarthritis at a regional, public hospital in Australia, to identify opportunities for pre-operative weight-loss intervention. METHODS: A retrospective review of patients who underwent elective primary total hip (THR), knee (TKR), and shoulder (TSR) replacement for osteoarthritis was conducted between December 2019 and December 2022. BMI data were collected at three time points: (1) general practitioner (GP) referral; (2) orthopaedic clinic review; and (3) pre-admission clinic (PAC) assessment. RESULTS: A total of 496 patients were included in the study, of which 205 underwent THR, 251 underwent TKR, and 40 underwent TSR. The mean patient age was 67 years, and 46.4% were female. At the time of GP referral, the mean body mass index (BMI) was 31.4 kg/m2. Across the study period, only 2% of patients experienced clinically significant weight loss pre-operatively (≥5% of total body weight). CONCLUSION: This study has demonstrated that very few patients lose weight prior to undergoing joint replacement in the public sector in Australia. This highlights the need for targeted non-surgical weight loss interventions for patients currently awaiting joint replacement.

Muscle Morphology Does Not Solely Determine Knee Flexion Weakness After Anterior Cruciate Ligament Reconstruction with a Semitendinosus Tendon Graft: A Combined Experimental and Computational Modeling Study.

The distal semitendinosus tendon is commonly harvested for anterior cruciate ligament reconstruction, inducing substantial morbidity at the knee. The aim of this study was to probe how morphological changes of the semitendinosus muscle after harvest of its distal tendon for anterior cruciate ligament reconstruction affects knee flexion strength and whether the knee flexor synergists can compensate for the knee flexion weakness. Ten participants 8-18 months after anterior cruciate ligament reconstruction with an ipsilateral distal semitendinosus tendon autograft performed isometric knee flexion strength testing (15°, 45°, 60°, and 90°; 0° = knee extension) positioned prone on an isokinetic dynamometer. Morphological parameters extracted from magnetic resonance images were used to inform a musculoskeletal model. Knee flexion moments estimated by the model were then compared with those measured experimentally at each knee angle position. A statistically significant between-leg difference in experimentally-measured maximal isometric strength was found at 60° and 90°, but not 15° or 45°, of knee flexion. The musculoskeletal model matched the between-leg differences observed in experimental knee flexion moments at 15° and 45° but did not well estimate between-leg differences with a more flexed knee, particularly at 90°. Further, the knee flexor synergists could not physiologically compensate for weakness in deep knee flexion. These results suggest additional factors other than knee flexor muscle morphology play a role in knee flexion weakness following anterior cruciate ligament reconstruction with a distal semitendinosus tendon graft and thus more work at neural and microscopic levels is required for informing treatment and rehabilitation in this demographic.

Stratification of Outpatient Physical Therapy Following Total Knee Arthroplasty: Knee Arthroplasty Physical Therapy Pathways (KAPPA) Nonrandomized Controlled Trial.

BACKGROUND: Outpatient physical therapy following total knee arthroplasty (TKA) is often considered crucial for an effective recovery. However, recent evidence suggests that a self-directed pathway may yield similar benefits to supervised care. Despite this, there appear to be no established criteria to determine who can successfully self-direct their rehabilitation versus those who would benefit from outpatient physical therapy. This study aimed to determine if early postoperative criteria can stratify TKA patients into a self-directed or supervised physical therapy pathway without compromising outcomes. METHODS: Overall, 60 TKA patients were initially allocated to a self-directed, unsupervised protocol for their postoperative rehabilitation. Baseline demographics, along with functional and self-reported outcomes, were assessed preoperatively and at 2 weeks, 6 weeks, and 4 months following surgery. Patients were referred to supervised outpatient physical therapy if they met any of the following Knee Arthroplasty Physical Therapy Pathways (KAPPA) criteria: (1) knee flexion range of motion <90 degrees; (2) knee extension range of motion lacking >10 degrees; or (3) dissatisfaction with the progress of their rehabilitation. RESULTS: At 2 weeks post-TKA, 28 participants met the KAPPA criteria for supervised physical therapy for reasons of knee flexion <90 degrees (61%), a lack of knee extension >10 degrees (36%), or not being satisfied with the progress of their recovery (3%). The remaining 32 participants continued with a self-directed rehabilitation pathway. All outcomes assessed favored the self-directed group at 2 weeks, however, after an average of 4 supervised physical therapy sessions at 4 months there were no longer any differences between the 2 groups. CONCLUSIONS: Over half of the included participants could self-direct their rehabilitation following TKA without supervised physical therapy while also maintaining excellent clinical outcomes. For those who met KAPPA criteria at 2 weeks post-TKA, 4 supervised physical therapy sessions appeared to be beneficial when outcomes were reassessed at 4 months.

Moment arm and torque generating capacity of semitendinosus following tendon harvesting for anterior cruciate ligament reconstruction: A simulation study.

Altered semitendinosus (ST) morphology and distal tendon insertion following anterior cruciate ligament reconstruction (ACLR) may reduce knee flexion torque generating capacity of the hamstrings via impaired ST force generation and/or moment arm. This study used a computational musculoskeletal model to simulate mechanical consequences of tendon harvest for ACLR on ST function by modeling changes in ST muscle tendon insertion point, moment arm, and torque generating capacity across a physiological range of motion. Simulated ST function was then compared between ACLR and uninjured contralateral limbs. Magnetic resonance imaging from 18 individuals with unilateral history of ACLR involving a hamstring autograft was used to analyse bilateral hamstring muscle (ST, semimembranosus, bicep femoris long head and short head) morphology and distal ST tendon insertion. The ACLR cohort was sub-grouped into those with and without ST regeneration. For each participant with ST regeneration (n = 7), a personalized musculoskeletal model was created including postoperative remodeling of ST using OpenSim 4.1. Knee flexion and internal rotation moment arms and torque generating capacities of hamstrings were evaluated. Bilateral differences were calculated with an asymmetry index (%) ([unaffected limb-affected limb]/[unaffected limb + affected limb]*100%). Smaller moment arms or knee torques within injured compared to uninjured contralateral limbs were considered a deficit. Compared to uninjured contralateral limbs, ACLR limbs with tendon regeneration (n = 7) had minor reductions in knee flexion (5.80% [95% confidence interval (CI) = 3.97-7.62]) and internal rotation (4.92% [95% CI = 2.77-7.07]) moment arms. Decoupled from muscle morphology, altered ST moment arms in ACLR limbs with tendon regeneration resulted in negligible deficits in knee flexion (1.20% [95% CI = 0.34-2.06]) and internal rotation (0.24% [95% CI = 0.22-0.26]) torque generating capacity compared to uninjured contralateral limbs. Coupled with muscle morphology, ACLR limbs with tendon regeneration had substantial deficits in knee flexion (19.32% [95% CI = 18.35-20.28]) and internal rotation (15.49% [95% CI = 14.56-16.41]) torques compared to uninjured contralateral limbs. Personalized musculoskeletal models with measures of ST distal insertion and muscle morphology provided unique insights into post-ACLR ST and hamstring function. Deficits in knee flexor and internal rotation moment arms and torque generating capacities were evident in those with ACLR even when tendon regeneration occurred. Future studies may wish to implement this framework in personalized musculoskeletal models following ACLR to better understand individual muscle function for injury prevention and treatment evaluation.

In Vitro Evaluation of Vancomycin-Induced Toxicity in Human Primary Knee Chondrocytes.

Septic arthritis as a complication of orthopaedic joint surgery can have catastrophic outcomes for patients. To minimise infection risk associated with elective orthopaedics, topical vancomycin during surgery has become increasingly common. Evidence suggests that high concentrations of vancomycin, following direct application of the drug to the joint, are toxic towards various local cell types in the joint, including chondrocytes. However, the mechanism of this vancomycin tissue toxicity is yet to be determined. The aim of this study was to evaluate the toxicity of vancomycin on chondrocytes and the mechanisms of cell death involved. Human primary knee chondrocytes were exposed to vancomycin (1.25-10 mg/mL) for 24 h and their viability assessed using the resazurin reduction assay in vitro. Specific cell death mechanisms and their contributors, including reactive oxygen species (ROS) production and apoptosis, were measured. This study showed that high concentrations of vancomycin (5 and 10 mg/mL) were toxic towards human primary knee chondrocyte cells, while lower concentrations (1.25 and 2.5 mg/mL) were not. Cell death studies found that this occurred through an apoptotic pathway. This study provides additional support that vancomycin in high doses is toxic towards chondrocytes and preliminary evidence that this toxicity occurs via apoptotic cell death mechanisms.

The addition of structured lifestyle modifications to a traditional exercise program for the management of patients with knee osteoarthritis: A systematic review and meta-analysis of randomised trials.

BACKGROUND: Guidelines recommend exercise for the management of knee osteoarthritis (OA), however, recently it has been suggested that including additional lifestyle modifications with a traditional exercise program may elicit greater benefits than exercise alone. OBJECTIVES: To investigate the influence of the addition of lifestyle modifications to a traditional exercise program, with respect to functional outcomes and quality of life among individuals with knee OA. DESIGN: Systematic review and meta-analysis. METHODS: Four databases were searched to identify randomised controlled trials comparing an exercise program, which included the addition of lifestyle modifications, to an exercise program alone in individuals with knee OA. Methodological quality of included studies was assessed via the PEDro scale. Results synthesis through meta-analysis using a random effects model was conducted to determine the pooled effect on eligible outcomes and a GRADE approach was utilised to rate the certainty of evidence. RESULTS: Meta-analysis of seven studies showed the inclusion of lifestyle modifications to an exercise program can further decrease pain intensity (SMD -0.68 [95% CI -1.26 to -0.10]), improve joint stiffness (MD -0.69 [95% CI -1.21, -0.17]) and increase physical function (MD -1.26 s ([95% CI -1.34, -1.17]) at six-months. Individual results showed improvements in quality of life with the addition of lifestyle modifications, however, this was not demonstrated through meta-analysis. CONCLUSION: This systematic review supports the inclusion of additional lifestyle modifications to a traditional exercise program, for pain intensity, joint stiffness and physical function for individuals with knee OA. TRIAL REGISTRATION: PROSPERO registration number: CRD42021279594.

Hamstring harvest results in significantly reduced knee muscular protection during side-step cutting two years after anterior cruciate ligament reconstruction.

The purpose of this study was to determine the effect of donor muscle morphology following tendon harvest in anterior cruciate ligament (ACL) reconstruction on muscular support of the tibiofemoral joint during sidestep cutting. Magnetic resonance imaging (MRI) was used to measure peak cross-sectional area (CSA) and volume of the semitendinosus (ST) and gracilis (GR) muscles and tendons (bilaterally) in 18 individuals following ACL reconstruction. Participants performed sidestep cutting tasks in a biomechanics laboratory during which lower-limb electromyography, ground reaction loads, whole-body motions were recorded. An EMG driven neuro-musculoskeletal model was subsequently used to determine force from 34 musculotendinous units of the lower limb and the contribution of the ST and GR to muscular support of the tibiofemoral joint based on a normal muscle-tendon model (Standard model). Then, differences in peak CSA and volume between the ipsilateral/contralateral ST and GR were used to adjust their muscle-tendon parameters in the model followed by a recalibration to determine muscle force for 34 musculotendinous units (Adjusted model). The combined contribution of the donor muscles to muscular support about the medial and lateral compartments were reduced by 52% and 42%, respectively, in the adjusted compared to standard model. While the semimembranosus (SM) increased its contribution to muscular stabilisation about the medial and lateral compartment by 23% and 30%, respectively. This computer simulation study demonstrated the muscles harvested for ACL reconstruction reduced their support of the tibiofemoral joint during sidestep cutting, while the SM may have the potential to partially offset these reductions. This suggests donor muscle impairment could be a factor that contributes to ipsilateral re-injury rates to the ACL following return to sport.

Morphology of proximal and distal human semitendinosus compartments and the effects of distal tendon harvesting for anterior cruciate ligament reconstruction.

The human semitendinosus muscle is characterized by a tendinous inscription separating proximal and distal neuromuscular compartments. As each compartment is innervated by separate nerve branches, potential exists for independent operation and control of compartments. However, the morphology and function of each compartment have not been thoroughly examined in an adult human population. Further, the distal semitendinosus tendon is typically harvested for use in anterior cruciate ligament reconstruction surgery, which induces long-term morphological changes to the semitendinosus muscle-tendon unit. It remains unknown if muscle morphological alterations following anterior cruciate ligament reconstruction are uniform between proximal and distal semitendinosus compartments. Here, we performed magnetic resonance imaging on 10 individuals who had undergone anterior cruciate ligament reconstruction involving an ipsilateral distal semitendinosus tendon graft 14 ± 4 months prior, extracting morphological parameters of the whole semitendinosus muscle and each individual compartment from both the (non-injured) contralateral and surgical legs. In the contralateral leg, volume and length of the proximal compartment were smaller than the distal compartment. No between-compartment differences in volume or length were found for anterior cruciate ligament reconstructed legs, likely due to greater shortening of the distal compared to the proximal compartment after anterior cruciate ligament reconstruction. The maximal anatomical cross-sectional area of both compartments was substantially smaller on the anterior cruciate ligament reconstructed leg but did not differ between compartments on either leg. The absolute and relative between-leg differences in proximal compartment morphology on the anterior cruciate ligament reconstructed leg were strongly correlated with the corresponding between-leg differences in distal compartment morphological parameters. Specifically, greater between-leg morphological differences in one compartment were highly correlated with large between-leg differences in the other compartment, and vice versa for smaller differences. These relationships indicate that despite the heterogeneity in compartment length and volume, compartment atrophy is not independent or random. Further, the tendinous inscription endpoints were generally positioned at the same proximodistal level as the compartment maximal anatomical cross-sectional areas, providing a wide area over which the tendinous inscription could mechanically interact with compartments. Overall, results suggest the two human semitendinosus compartments are not mechanically independent.

Shape differences in the semitendinosus following tendon harvesting for anterior cruciate ligament reconstruction.

Following hamstring autograft anterior cruciate ligament reconstruction (ACLR), muscle length, cross-sectional area, and volume are reduced. However, these discrete measures of morphology do not account for complex three-dimensional muscle shape. The primary aim of this study was to determine between-limb semitendinosus (ST) shape and regional morphology differences in young adults following tendon harvest for ACLR and to compare these differences with those in healthy controls. In this cross-sectional study, magnetic resonance imaging was performed on 18 individuals with unilateral ACLR and 18 healthy controls. Bilaterally, ST muscles were segmented, and shape differences assessed between limbs and compared between groups using Jaccard index (0-1) and Hausdorff distance (mm). Length (cm), peak cross-sectional area (cm2 ), and volume (cm3 ) were measured for the entire muscle and proximal, middle, and distal regions, and compared between limbs and groups. Compared to healthy controls, the ACLR group had significantly (p < 0.001, Cohen's d = -2.33) lower bilateral ST shape similarity and shape deviation was significantly (p < 0.001, d = 2.12) greater. Shape deviation was greatest within the distal region of the ACLR (Hausdorff: 23.1 ± 8.68 mm). Compared to both the uninjured contralateral limb and healthy controls, deficits in peak cross-sectional area and volume in ACLR group were largest in proximal (p < 0.001, d = -2.52 to -1.28) and middle (p < 0.001, d = -1.81 to -1.04) regions of the ST. Overall, shape analysis provides unique insight into regional adaptations in ST morphology post-ACLR. Findings highlight morphological features in distal ST not identified by traditional discrete morphology measures. Clinical significance: Following ACLR, risk of a secondary knee or primary hamstring injury has been reported to be between 2-to-5 times greater compared to those without ACLR. Change in semitendinosus (ST) shape following ACLR may affect force transmission and distribution within the hamstrings and might contribute to persistent deficits in knee flexor and internal rotator strength.

Study protocol for double-blind, randomised placebo-controlled trial evaluating semitendinosus function and morbidity following tendon harvesting for anterior cruciate ligament reconstruction augmented by platelet-rich plasma.

INTRODUCTION: Anterior cruciate ligament (ACL) rupture is debilitating, often requiring surgical reconstruction. An ACL reconstruction (ACLR) using a tendon autograft harvested from the semitendinosus results in substantial injury to the donor muscle. Following ACLR, patients rarely return to their preinjury level of physical activity, are at elevated risk of secondary lower limb injuries and early onset knee osteoarthritis. To date, no randomised controlled trial has evaluated the efficacy of platelet-rich plasma (PRP) in aiding knee function and semitendinosus morphology of following ALCR. METHODS AND ANALYSIS: This is a multicentre double-blind randomised placebo-controlled trial. Fifty-four ACLR patients aged 18-50 years will be randomised to receive either a single application of PRP (ACLR+) or placebo saline (ACLR) into the semitendinosus harvest zone at the time of surgery. All patients will undergo normal postoperative rehabilitation recommended by the attending orthopaedic surgeon or physiotherapist. The primary outcome measure is between-limb difference (ACLR compared with intact contralateral) in isometric knee flexor strength at 60o knee flexion, collected 10-12 months postsurgery. This primary outcome measure will be statistically compared between groups (ACLR+ and standard ACLR). Secondary outcome measures include bilateral assessments of hamstring muscle morphology via MRI, biomechanical and electromyographic parameters during an anticipated 45° running side-step cut and multidirectional hopping task and patient-reported outcomes questionaries. Additionally, patient-reported outcomes questionaries will be collected before (baseline) as well as immediately after surgery, and at 2-6 weeks, 3-4 months, 10-12 months and 22-24 months postsurgery 10-12 months following surgery. ETHICS AND DISSEMINATION: Ethics approval has been granted by Griffith University Human Research Ethics Committee, Greenslopes Research and Ethics Committee, and Royal Brisbane & Women's Hospital Human Research Ethics Committee. Results will be submitted for publication in a peer-reviewed medical journal. TRIAL REGISTRATION NUMBER: ACTRN12618000762257p.

A Prospective, Longitudinal Study of the Influence of Obesity on Total Knee Arthroplasty Revision Rate: Results from the Australian Orthopaedic Association National Joint Replacement Registry.

BACKGROUND: The aim of this study was to investigate the relationship of obesity with all-cause revision and revision for infection, loosening, instability, and pain after total knee arthroplasty (TKA) performed in Australia. METHODS: Data for patients undergoing primary TKA for osteoarthritis from January 1, 2015, to December 31, 2020, were obtained from the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR). The rates of all-cause revision and revision for infection, loosening, instability, and pain were compared for non-obese patients (body mass index [BMI], 18.50 to 29.99 kg/m 2 ), class-I and II obese patients (BMI, 30.00 to 39.99 kg/m 2 ), and class-III obese patients (BMI, ≥40.00 kg/m 2 ). The results were adjusted for age, sex, tibial fixation, prosthesis stability, patellar component usage, and computer navigation usage. RESULTS: During the study period, 141,673 patients underwent primary TKA for osteoarthritis in Australia; of these patients, 48.0% were class-I or II obese, and 10.6% were class-III obese. The mean age was 68.2 years, and 54.7% of patients were female. The mean follow-up period was 2.8 years. Of the 2,655 revision procedures identified, the reasons for the procedures included infection in 39.7%, loosening in 14.8%, instability in 12.0%, and pain in 6.1%. Class-I and II obese patients had a higher risk of all-cause revision (hazard ratio [HR], 1.12 [95% confidence interval (CI), 1.03 to 1.22]; p = 0.007) and revision for infection (HR, 1.25 [95% CI, 1.10 to 1.43]; p = 0.001) than non-obese patients. Class-III obese patients had a higher risk of all-cause revision after 1 year (HR, 1.30 [95% CI, 1.14 to 1.52]; p < 0.001), revision for infection after 3 months (HR, 1.72 [95% CI, 1.33 to 2.17]; p < 0.001), and revision for loosening (HR, 1.39 [95% CI, 1.00 to 1.89]; p = 0.047) than non-obese patients. The risks of revision for instability and pain were similar among groups. CONCLUSIONS: Obese patients with knee osteoarthritis should be counseled with regard to the increased risks associated with TKA, so they can make informed decisions about their health care. Health services and policymakers need to address the issue of obesity at a population level. LEVEL OF EVIDENCE: Prognostic Level III . See Instructions for Authors for a complete description of levels of evidence.

Obesity is associated with an increased risk of undergoing knee replacement in Australia.

BACKGROUND: Obesity is associated with the development of knee osteoarthritis (OA). The aim of this study was to examine the incidence of obesity in patients undergoing knee replacement (KR) for OA in Australia compared to the incidence of obesity in the general population. METHODS: A cohort study was conducted, comparing data from the Australian Bureau of Statistics (ABS) 2017-2018 National Health Survey with data from the National Joint Replacement Registry. The distribution of patients who underwent KR from July 2017 to June 2018 by BMI category was compared to the distribution of the general population, in age and gender sub-groups. RESULTS: During the study period, 35.6% of Australian adults were overweight and 31.3% were obese. Of the 56 217 patients who underwent primary KR for OA, 31.9% were overweight and 57.7% were obese. The relative risk of undergoing KR for OA increased with increasing BMI category. Class 1, 2 and 3 obese females aged 55-64 years were 4.7, 8.4 and 17.3 times more likely to undergo KR than their normal weight counterparts, respectively. Males in the same age and BMI categories were 3.4, 4.5 and 5.8 times more likely to undergo KR, respectively. Class 3 obese patients underwent KR 7 years younger, on average, than normal weight individuals. CONCLUSION: Obesity is associated with an increased risk of undergoing KR, and at a younger age, particularly for females. There is an urgent need for a societal level approach to address the prevalence of obesity, to reduce the burden of obesity related KR.

Vancomycin Soaking Is Highly Cost-Effective in Primary ACLR Infection Prevention: A Cost-Effectiveness Study.

BACKGROUND: Although presoaking grafts in vancomycin has been demonstrated to be effective in observational studies for anterior cruciate ligament reconstruction (ACLR) infection prevention, the economic benefit of the technique is uncertain. PURPOSE: To 1) determine the cost-effectiveness of vancomycin presoaking during primary ACLR to prevent postoperative joint infections and 2) to establish the break-even cost-effectiveness threshold of the technique and determine its cost-effectiveness across various international health care settings. STUDY DESIGN: Economic and decision analysis; Level of evidence, 2. METHODS: A Markov model was used to determine cost-effectiveness and the incremental cost-effectiveness ratio of additional vancomycin presoaking compared with intravenous antibiotic prophylaxis alone. A repeated search of the PubMed, SCOPUS, and Cochrane Central Register of Controlled Trials databases, using the same criteria as a recent meta-analysis, was completed. A repeated meta-analysis of 9 cohort studies (level 3 evidence) was completed to determine the odds ratio of infection with vancomycin presoaking compared with intravenous antibiotics alone. Estimated costs of the vancomycin technique, treatment of infection, and further surgery were sourced from local hospitals and literature. Transitional probabilities for further surgery, including revision reconstruction and primary arthroplasty, were obtained from the literature. Probabilistic sensitivity analyses and a 1-way sensitivity analysis were performed to evaluate the ACLR infection rate break-even threshold for which the vancomycin technique would be no longer cost-effective. RESULTS: The vancomycin soaking technique provides expected cost savings of $660 (USA), A$581 (Australia), and €226 (Spain) per patient. There was an improvement in the quality-adjusted life-years of 0.007 compared with intravenous antibiotic prophylaxis alone (4.297 vs 4.290). If the infection rate is below 0.014% with intravenous antibiotics alone, the vancomycin wrap would no longer be cost-effective. CONCLUSION: The vancomycin presoaking technique is a highly cost-effective method to prevent postoperative septic arthritis after primary ACLR.

Patellar cartilage increase following ACL reconstruction with and without meniscal pathology: a two-year prospective MRI morphological study.

BACKGROUND: Anterior cruciate ligament reconstruction (ACLR) together with concomitant meniscal injury are risk factors for the development of tibiofemoral (TF) osteoarthritis (OA), but the potential effect on the patellofemoral (PF) joint is unclear. The aim of this study was to: (i) investigate change in patellar cartilage morphology in individuals 2.5 to 4.5 years after ACLR with or without concomitant meniscal pathology and in healthy controls, and (ii) examine the association between baseline patellar cartilage defects and patellar cartilage volume change. METHODS: Thirty two isolated ACLR participants, 25 ACLR participants with combined meniscal pathology and nine healthy controls underwent knee magnetic resonance imaging (MRI) with 2-year intervals (baseline = 2.5 years post-ACLR). Patellar cartilage volume and cartilage defects were assessed from MRI using validated methods. RESULTS: Both ACLR groups showed patellar cartilage volume increased over 2 years (p < 0.05), and isolated ACLR group had greater annual percentage cartilage volume increase compared with controls (mean difference 3.6, 95% confidence interval (CI) 1.0, 6.3%, p = 0.008) and combined ACLR group (mean difference 2.2, 95% CI 0.2, 4.2%, p = 0.028). Patellar cartilage defects regressed in the isolated ACLR group over 2 years (p = 0.02; Z = - 2.33; r = 0.3). Baseline patellar cartilage defect score was positively associated with annual percentage cartilage volume increase (Regression coefficient B = 0.014; 95% CI 0.001, 0.027; p = 0.03) in the pooled ACLR participants. CONCLUSIONS: Hypertrophic response was evident in the patellar cartilage of ACLR participants with and without meniscal pathology. Surprisingly, the increase in patellar cartilage volume was more pronounced in those with isolated ACLR. Although cartilage defects stabilised in the majority of ACLR participants, the severity of patellar cartilage defects at baseline influenced the magnitude of the cartilage hypertrophic response over the subsequent ~ 2 years.

Effects of Pubertal Maturation on ACL Forces During a Landing Task in Females.

BACKGROUND: Rates of anterior cruciate ligament (ACL) rupture in young people have increased by >70% over the past two decades. Adolescent and young adult females are at higher risk of ACL injury as compared with their prepubertal counterparts. PURPOSE: To determine ACL loading during a standardized drop-land-lateral jump in females at different stages of pubertal maturation. STUDY DESIGN: Controlled laboratory study. METHODS: On the basis of the Tanner classification system, 19 pre-, 19 early-/mid-, and 24 late-/postpubertal females performed a standardized drop-land-lateral jump while 3-dimensional body motion, ground-reaction forces, and surface electromyography data were acquired. These data were used to model external biomechanics, lower limb muscle forces, and knee contact forces, which were subsequently used in a validated computational model to estimate ACL loading. Statistical parametric mapping analysis of variance was used to compare ACL force and its causal contributors among the 3 pubertal maturation groups during stance phase of the task. RESULTS: When compared with pre- and early-/midpubertal females, late-/postpubertal females had significantly higher ACL force with mean differences of 471 and 356 N during the first 30% and 48% to 85% of stance, and 343 and 274 N during the first 24% and 59% to 81% of stance, respectively, which overlapped peaks in ACL force. At the point of peak ACL force, contributions from sagittal and transverse plane loading mechanisms to ACL force were higher in late-/postpubertal compared with pre- and early-/midpubertal groups (medium effect sizes from 0.44 to 0.77). No differences were found between pre- and early-/midpubertal groups in ACL force or its contributors. CONCLUSION: The highest ACL forces were observed in late-/postpubertal females, consistent with recently reported rises of ACL injury rates in females aged 15 to 19 years. It is important to quantify ACL force and its contributors during dynamic tasks to advance our understanding of the loading mechanism and thereby provide guidance to injury prevention. CLINICAL RELEVANCE: Growth of ACL volume plateaus around 10 years of age, before pubertal maturation, meaning that a late-/postpubertal female could have an ACL of similar size to their less mature counterparts. However, late-/postpubertal females have higher body mass requiring higher muscle forces to accelerate the body during dynamic tasks, which may increase ACL loading. Thus, if greater forces develop in these females, in part because of their increased body mass, these higher forces will be applied to an ACL that is not proportionally larger. This may partially explain the higher rates of ACL injury in late-/postpubertal females.

Cost of septic and aseptic revision total knee arthroplasty: a systematic review.

BACKGROUND: The increasing incidence of primary total knee arthroplasty (TKA) has led to an increase in both the incidence and the cost burden of revision TKA procedures. This study aimed to review the literature on the cost of revision TKA for septic and aseptic causes and to identify the major cost components contributing to the cost burden. METHODS: We searched MEDLINE (OvidSp), Embase, Web of Science, Cochrane Library, EconLit, and Google Scholar to identify relevant studies. Selection, data extraction and assessment of the risk of bias and cost transparency within the studies were conducted by two independent reviewers, after which the cost data were analysed narratively for 1- or 2-stage septic revision without re-revision; 2-stage septic revision with re-revision; and aseptic revision with and without re-revision, respectively. The major cost components identified in the respective studies were also reported. RESULTS: The direct medical cost from the healthcare provider perspective for high-income countries for 2-stage septic revision with re-revision ranged from US$66,629 to US$81,938, which can be about 2.5 times the cost of 1- or 2-stage septic revision without re-revision, (range: US$24,027 - US$38,109), which can be about double the cost of aseptic revision without re-revision (range: US$13,910 - US$29,213). The major cost components were the perioperative cost (33%), prosthesis cost (28%), and hospital ward stay cost (22%). CONCLUSIONS: Septic TKA revision with re-revision for periprosthetic joint infection (PJI) increases the cost burden of revision TKA by 4 times when compared to aseptic single-stage revision and by 2.5 times when compared to septic TKA revision that does not undergo re-revision. Cost reductions can be achieved by reducing the number of primary TKA that develop PJI, avoidance of re-revisions for PJI, and reduction in the length of stay after revision. TRIAL REGISTRATION: PROSPERO; CRD42020171988 .

Biomechanical Comparison of an All-Inside Meniscal Repair Device Construct Versus Pullout Sutures for Arthroscopic Transtibial Repair of Posterior Medial Meniscus Root Tears: A Matched-Pair Cadaveric Study.

BACKGROUND: Meniscus root repairs are important for restoring knee function after a complete meniscus root tear. Various suturing patterns have been proposed for the root repair. The 2-simple-stitches (TSS) method is currently the preferred technique, as it is simplest to perform and allows the least displacement of the meniscus root. PURPOSE: To compare the biomechanical properties of a posterior medial meniscus transtibial root repair consisting of an all-inside meniscal repair device (AMRD) construct with the TSS pullout suture pattern. STUDY DESIGN: Controlled laboratory study. METHODS: Ten pairs of cadaveric medial menisci were prepared with 1 of the 2 constructs. The constructs were randomized between pairs. All constructs were subjected to preloading with 2 N for 10 seconds and then cyclic loading from 5 N to 20 N for 1000 cycles at a frequency of 0.5 Hz. Subsequently, the menisci were loaded to failure at a rate of 0.5 mm/s. All loads were applied in-line with the circumferential meniscal fibers near the posterior medial meniscal horn. RESULTS: The mean yield load and stiffness were similar for both constructs. The elongation after cyclic loading was greater for the AMRD. The displacement at both yield load and ultimate failure were also higher for the AMRD. The ultimate failure load of the AMRD was also significantly higher. During load to failure, the mode of failure in the AMRD was heterogeneous. All the TSS constructs failed by suture cutout. CONCLUSION: Posterior medial meniscus root repairs using both the AMRD and TSS constructs have elongation under the biomechanically acceptable threshold of 3 mm. The stiffness and yield loads indicate similar mechanical properties of the constructs. However, the significantly higher elongation for the AMRD leaves the TSS method as the preferred option for transtibial repairs. Despite this, the AMRD construct may still represent a viable alternative to the TSS suture pattern, comparable to alternative suture patterns with similar limitations. CLINICAL RELEVANCE: The AMRD construct may represent a viable alternative to the TSS suture pattern.

Editorial Commentary: Is It Time for the Vancomycin Wrap to Become a Universal Recommendation for the Prevention of Septic Arthritis Following Anterior Cruciate Ligament Reconstruction?

Septic arthritis is a devastating complication of anterior cruciate ligament (ACL) reconstruction, which can still occur in approximately 1% of patients despite appropriate intravenous antibiotic prophylaxis and other recommended preventative measures being undertaken. The infection is most likely secondary to the autograft becoming contaminated during harvest and preparation, introducing bacteria into the joint on insertion. Presoaking ACL grafts in 5 mg/mL vancomycin is a novel method developed to eradicate this bacterial contamination and is supported by compelling Level III evidence from multiple observational trials showing a dramatic reduction in infection rates without any evidence of increased graft failure. As such, it is time for this technique to become a universal recommendation? That said, as observational studies using a historical cohort as a comparator are at risk of various biases, Level I evidence is ultimately required for infection prophylaxis methods to be recognized as a universal recommendation in infection control guidelines. Consequently, future research endeavors on the "vancomycin wrap" should focus on randomized controlled trials, possibly nested within ACL registries.

Cost of Revision Total Knee Replacement: A Protocol for Systematic Review and Meta-Analysis.

BACKGROUND: A major limitation of total knee replacement (TKR), as with other joint replacements, is the risk of revision. Revision TKR is associated with high risk and economic burden to patients, healthcare providers, and societies. It will be worthwhile to assess the economic burden of revision TKR across countries or different study settings. This study aims to review the literature on the cost of revision TKR to assess costs across countries and studies, estimate a pooled cost estimate for homogenous data, and identify major cost components that contribute to the cost burden. METHODS: We will conduct a search of the MEDLINE (OvidSp), EMBASE, Web of Science, Cochrane Library, EconLit, and Google Scholar databases to identify relevant studies, and will use an optimally designed search approach to search for relevant studies. EndNote library will be used to manage the searched studies. Selection will be undertaken in two phases-screening and eligibility. Study selection, data extraction, and assessment of the risk of bias will be performed in duplicate, after which the data will be analysed narratively and a meta-analysis performed for homogenous studies, if possible. DISCUSSION: This protocol provides a proposed stepwise plan for conducting a systematic review and meta-analysis of the cost of revision TKR. Findings from this systematic review will provide information about the cost across settings and identify the major cost drivers of revision TKR, which will, in turn, stimulate efforts to minimize the cost. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42020171988.