Biomechanical analysis during single-leg squat in individuals with knee osteoarthritis

Backgroud: The single-leg squat (SLS) is a functional task to evaluate the abnormal movement patterns and potential neuromuscular deficits in the lower limbs. Still, it is unknown if SLS could provide information to older adults with knee osteoarthritis (KOA). The study’s objective was to analyze the EMG pattern, kinematics, and postural control in individuals with and without KOA during SLS.Methods: Participated in this study, 60 volunteers of both sexes, 30 had KOA (allocated into the KOA group - KOAG), and 30 were healthy (allocated into the Healthy Group - HG) performing the single-leg squat. Surface electromyography (EMG) was assessed for the gastrocnemius medialis (GM), biceps femoris (BF), gluteus medius (GLM), rectus femoris (RF), vastus medialis (VM), vastus lateralis (VL), and tibialis anterior (TA) in two phases (downward – P1 and upward – P2). The kinematic data was evaluated using an electrogoniometer. The center of pressure (CoP) was obtained using data collected from a force plate.Results: EMG activity was increased for GM and TA muscles during the P1 of the movement and the GM and GLM muscles during P2 of the movement. The angular displacement of the KOAG was lower when compared with the HG. There was no statistical difference for the co-contraction and postural control data.Conclusions: The SLS analysis showed that EMG activity of the muscles TA, GM, and GLM was increased in the KOAG, but this pattern could be affected by fear of movement leading to reduced knee angular displacement.     

A novel single-leg squat test with speed and accuracy requirements: Reliability and validity in anterior cruciate ligament reconstructed individuals

BackgroundSome traditional single-leg squat tests focused on number of repetitions may not demand precise control of lower limb dynamic alignment, especially in the frontal and transverse planes. The primary objective of this study was to evaluate test–retest reliability and construct validity of a novel single-leg squat test – the ‘precision-squat test’ (PST) – designed to assess performance under varying task demands that can impact the execution of lower limb movements. A secondary objective was to investigate whether musculoskeletal factors predict performance in the PST in healthy individuals.MethodsThirty healthy participants were assessed to verify test–retest reliability. To verify the test’s construct validity, we compared the performance of 21 anterior cruciate ligament reconstructed (ACLR) individuals and 21 matched controls. Finally, 36 healthy individuals were assessed to verify the musculoskeletal factors related to PST performance. All participants performed the PST: they executed single-leg squats while moving a laser pointer (attached to the thigh) between two targets. We varied target size and distance between targets to manipulate the task difficulty.ResultsReliability of the PST was excellent at all demand levels (intraclass correlation coefficient (ICC)_(3,2) > 0.93). Squat time increased under test conditions involving higher task difficulty (P < 0.001) and in ACLR individuals compared with age-matched controls (P < 0.05). Regression analyses revealed that reduced knee extensors and hip external rotators torques are related to increased squat time (P < 0.05).ConclusionsPST is a valid and reliable tool to assess performance of healthy and ACLR individuals. In addition, hip and knee strength are associated with performance during the test.     

Can robot-assisted total knee arthroplasty be a cost-effective procedure? A Markov decision analysis

BackgroundTotal knee arthroplasty (TKA) is a frequently and increasingly performed surgery in the treatment of disabling knee osteoarthritis. The rising number of procedures and related revisions pose an increasing economic burden on health care systems. In an attempt to lower the revision rate due to component malalignment and soft tissue imbalance in TKA, robotic assistance (RA) has been introduced in the operating theatre.The primary objective of this study is to provide the results of a theoretical, preliminary cost-effectiveness analysis of RA TKA.MethodsA Markov state-transition model was designed to model the health status of sixty-seven-year-old patients in need of TKA due to primary osteoarthritis over a twenty-year period following their knee joint replacement. Transitional probabilities and independent variables were extracted from existing literature.ResultsThe value attributed to the utility both for primary and revision surgery has the biggest impact on the ICER, followed by the rate of successful primary surgery and the cost of RA-technology. Only 2.18% of the samples yielded from the probabilistic sensitivity analysis proved to be cost-effective (threshold set at $50000/QALY). A calculated surgical volume of at least 253 cases per robot per year is needed to prove cost-effective taking the predetermined parameter values into account.ConclusionBased upon transitional probabilities and independent variables derived from existing studies, RA TKA may be cost-effective at a surgical volume of 253 cases per robot per year when compared to conventional TKA.     

Consensus guidelines for management of patellofemoral instability

BackgroundThe aim of this consensus process was to provide robust national guidelines to assist with decision making with regards to surgical management of patellofemoral instability.MethodsA national group of surgeons, physiotherapists, basic scientists and a radiologist with expert experience in patellofemoral instability was convened. A formal consensus process was undertaken using validated methodology. They reviewed the existing literature, performed a group consensus meeting to develop recommendations and followed this with a wider consultation meeting with an open invitation for final ratification. The guidelines were reviewed and authorised by the BASK executive committee, followed by the British Orthopaedic Association prior to final publication.ResultsThe review of the literature confirmed a significant absence of an evidence base to guide clinicians in the surgical management of patellofemoral instability. The consensus process outlined guidance relating to diagnosis and clinical assessment, appropriate imaging modalities, recommendations for surgical options and appropriate post operative physiotherapy. Following wide invitation to contribute to the final document, 102 people responded. Twenty six of those provided additional comments which were blinded, discussed and included or excluded following further discussion amongst the working group.ConclusionPatellofemoral instability is a complex pathology with multiple surgical options available to those who decide surgery is indicated. In the absence of a strong evidence base, these guidelines aim to assist with that decision making process and will pave the way for more robust clinical trials in the future.     

Financial analysis of revision knee surgery at a tertiary referral centre as classified according to the Revision Knee Complexity Classification (RKCC)

BackgroundRevision total knee arthroplasty (rTKA) can be complex, with greater costs to the treating hospital than primary TKA. A rTKA regional network has been proposed in England. The aim of this work was to accurately quantify current costs and reimbursement for the rTKA service and to assess whether costs are proportional to case complexity at a tertiary referral centre within the National Health Service (NHS).MethodsA review of all rTKA performed at our institution over two consecutive financial years (2017–2019) was performed. Cases were classified according to the Revision Knee Complexity Classification (RKCC) and by mode of failure; “infected” and “non-infected”. Financial data was acquired through Patient-Level Information and Costing System (PLICS). The primary outcome was the financial difference between tariff and cost per episode. Comparisons between groups were analysed using analysis of variance and two-tailed unpaired t-test as appropriate.Results159 patients underwent 188 rTKA procedures. Length of stay and cost significantly increased between complexity groups (p < 0.0001) and for infected revisions (p < 0.0001). All groups sustained a mean deficit but this significantly increased with revision complexity (from £1,903 to £5,269 per case) and for infected revisions. The total deficit to the Trust for the two-year rTKA service was £667,091.ConclusionsThe current level of NHS reimbursement are inadequate for centres that offer rTKA and should be more closely aligned to case complexity. An increase in the most complex rTKA at major revision centres will undoubtedly place an even greater strain on the finances of these units.     

Revision knee arthroplasty: Can good outcomes be achieved at lower volumes?

BackgroundThe National Joint Registry (NJR) demonstrates a re-revision rate for primary knee arthroplasty of 14.2% at 7 years. The 2015 Getting it Right First Time (GIRFT) report highlighted that 58% of surgeons undertaking revision knee arthroplasty (RKA) performed fewer than five cases per year. It has been suggested that revision cases be centralised in specialist centres with a multidisciplinary team (MDT) approach. Such a hub and spoke or cluster models may still require revision surgery to be performed at relatively low volume units.MethodsAn analysis of RKA surgery performed in a four surgeon, lower volume revision knee unit over 10 years to December 2016 was undertaken. The effect of the introduction of a MDT was reviewed. The minimum follow up was two years. The primary outcome measure was re-revision. Hospital data as well as individual surgeon NJR reports were used to ensure all re-revisions were accounted for. Outcome scores were available for 68% of cases.ResultsThere were 192 RKAs performed in 187 patients at a mean (stdev) of 6.3 (5.4) years from the index procedure. The mean age at surgery was 68.2 (10.9) years. Twenty nine (15.5%) patients had died at the time of final review. Twelve (6.3%) cases required a further revision procedure. The commonest complication was stiffness requiring MUA. The overall 7 year survivorship was 94.9% (95% CI 90.2–97.3). The mean Oxford score at 5.4 years was 30.4 (10.4).ConclusionsRKA can be reliably performed at lower volume centres with appropriate MDT systems in place.     

Patellar resurfacing has minimal impact on in vitro tibiofemoral kinematics during deep knee flexion in total knee arthroplasty

BackgroundWhile patellar resurfacing can affect patellofemoral kinematics, the effect on tibiofemoral kinematics is unknown. We hypothesized that patellar resurfacing would affect tibiofemoral kinematics during deep knee flexion due to biomechanical alteration of the extensor mechanism.MethodsWe performed cruciate-retaining TKA in fresh-frozen human cadaveric knees (N = 5) and recorded fluoroscopic kinematics during deep knee flexion before and after the patellar resurfacing. To simulate deep knee flexion, cadaver knees were tested on a dynamic, quadriceps-driven, closed-kinetic chain simulator based on the Oxford knee rig design under loads equivalent to stair climbing. To measure knee kinematics, a 2-dimensional to 3-dimensional fluoroscopic registration technique was used. Component rotation, varus-valgus angle, and anteroposterior translation of medial and lateral contact points of the femoral component relative to the tibial component were calculated over the range of flexion.ResultsThere were no significant differences in femoral component external rotation (before patellar resurfacing: 6.6 ± 2.3°, after patellar resurfacing: 7.2 ± 1.8°, p = 0.36), and less than 1° difference in femorotibial varus-valgus angle between patellar resurfacing and non-resurfacing (p = 0.01). For both conditions, the medial and lateral femorotibial contact points moved posteriorly from 0° to 30° of flexion, but not beyond 30° of flexion. At 10° of flexion, after patellar resurfacing, the medial contact point was more anteriorly located than before patellar resurfacing.ConclusionDespite the potential for alteration of the knee extensor biomechanics, patellar resurfacing had minimal effect on tibiofemoral kinematics. Patellar resurfacing, if performed adequately, is unlikely to affect postoperative knee function.     

The effect of surgical approach in total knee replacement on outcomes. An analysis of 875,166 elective operations from the National Joint Registry for England,Wales, Northern Ireland and the Isle of Man

BackgroundTotal knee replacement (TKR) is clinically and cost-effective. The surgical approach employed influences the outcome, however there is little generalisable and robust evidence to guide practice. We compared outcomes between the common primary TKR surgical approaches.Methods875,166 primary TKRs captured in the National Joint Registry, linked to hospital inpatient, mortality and patient reported outcome measures (PROMs) data, with up to 15.75 years follow-up were analysed. There were 10 surgical approach groups: medial parapatellar, midvastus, subvastus, lateral parapatellar, ‘other’ and their minimally invasive versions. Survival methods were used to compare revision rates and 45-day mortality. Groups were compared using Cox proportional hazards regression and Flexible Parametric Survival Modelling (FPM). Confounders included age at surgery, sex, risk group (indications additional to osteoarthritis), American Society of Anesthesiologists grade, TKR fixation, year of primary, body mass index, and for mortality, deprivation and Charlson comorbidity subgroups. PROMs were analysed with regression modelling or non-parametric methods.ResultsThe conventional midvastus approach was associated with lower revision rates (Hazard Rate Ratio (HRR) 0.80 (95% CI 0.71–0.91) P = 0.001) and the lateral parapatellar with higher revision rates (HRR 1.35 (95% CI 1.12–1.63) P = 0.002) compared to the conventional medial parapatellar approach. Mortality rates were similar between approaches. PROMs showed statistically significant, but not clinically important, differences.ConclusionsThere is little difference in PROMs between the various surgical approaches in TKR with all resulting in good outcomes. However, the conventional midvastus approach (used in 3% of cases) was associated with a 20% reduced risk of revision surgery compared to the most commonly used knee approach (the conventional medial parapatellar: used in 91.9% of cases). This data supports the use of the midvastus approach and thus surgeons should consider utilising this approach more frequently. Minimally invasive approaches did not appear to convey any clinical advantage in this study over conventional approaches for primary TKR.     

Wide en bloc resection of an extraskeletal myxoid chondrosarcoma about the knee with single-stage knee extensor mechanism reconstruction: A case report

Soft tissue sarcomas about the patellar tendon necessitate wide resection and thus present a significant reconstructive challenge. This article describes the novel use of a synthetic mesh graft to reconstruct the knee extensor mechanism as a single stage procedure after wide en bloc resection of an extraskeletal myxoid chondrosarcoma (EMC) in a patient with an invasive mass that was intimately associated with her patellar tendon.     

The effect of remotely delivered lifestyle interventions on cognition in older adults without dementia: A systematic review and meta-analysis

Up to 40% of dementias may be preventable via risk factor modification. This inference has motivated the development of lifestyle interventions for reducing cognitive decline. Typically delivered to older adults face-to-face, the COVID-19 pandemic has necessitated their adaptation for remote delivery. We systematically reviewed randomized controlled trials of remotely delivered lifestyle interventions (≥4 weeks duration and delivered >50% remotely), for adults aged ≥ 60 without dementia, examining effects on objective cognitive measures. Comparators were active (face-to-face or remote) or passive. Ten studies (n = 2967) comprising multidomain (k = 4), physical activity (k = 3) or psychosocial (k = 3) remote interventions were included. Data were synthesized using robust variance estimation meta-analysis. The pooled estimate comparing the effect of remote interventions versus comparators on cognition was not significant (g=−0.02; 95%CI [−0.14, 0.09]; p = .66); subgroup analyses by type of intervention or comparator also yielded non-significant effects. Most studies had low risk of bias. Current evidence to support remote lifestyle interventions is limited. Included studies were conducted pre-pandemic, and evaluated individual, rather than group interventions. Future studies may exploit the greater digital connectivity of older people since the pandemic. Group formats, more frequently efficacious than individual interventions in face-to-face dementia prevention trials, may be a rational approach for future remote trials.