Widening of tibial resection boundaries increases the rate of femoral component valgus and internal rotation in functionally aligned TKA.

PURPOSE: The purpose of this study was to investigate the influence of increasing the tibial boundaries in functional alignment on femoral component orientation in total knee arthroplasty (TKA). METHODS: A retrospective review of a database of robotic-assisted TKAs using a digital joint tensioning device was performed (BalanceBot®; Corin). A total of 692 TKAs with correctable deformity were included. Functional alignment with a tibia-first balancing technique was simulated by performing an anatomic tibial resection to recreate the native medial proximal tibial angle within certain boundaries (A, 87-90°; B, 86-90°; C, 84-92°), while accounting for wear. After balancing the knee, the resulting amount of femoral component outliers in the coronal and axial plane was calculated for each group and correlated to the coronal plane alignment of the knee (CPAK) classification. RESULTS: The proportion of knees with high femoral component varus (>96°) or valgus (<87°) alignment increased from 24.5% (n = 170) in group A to 26.5% (n = 183) in group B and 34.2% (n = 237) in group C (p < 0.05). Similarly, more knees with high femoral component external rotation (>6°) or internal rotation (>3°) were identified in group C (33.4%, n = 231) than in group B (23.7%, n = 164) and A (18.4%, n = 127) (p < 0.05). There was a statistically significant (p < 0.01) overall increase in knees with both femoral component valgus <87° and internal rotation >3° from group A (4.0%, n = 28) to B (7.7%, n = 53) and C (15.8%, n = 109), with CPAK type I and II showing a 12.9- and 2.9-fold increase, respectively. CONCLUSION: Extending the tibial boundaries when using functional alignment with a tibia-first balancing technique in TKA leads to a statistically significant higher percentage of knees with a valgus lateral distal femoral angle < 87° and >3° internal rotation of the femoral component, especially in CPAK type I and II. LEVEL OF EVIDENCE: Level IV.

NAVIO RATKA shows similar rates of hemoglobin-drop, adverse events, readmission and early revision vs conventional TKA: a single centre retrospective cohort study.

PURPOSE: Despite widespread adoption of NAVIO robotic-assisted total knee arthroplasty (NAVIO RATKA) in clinical practice, clinical outcome in terms of adverse events and complications remains unclear. The purpose of this study was to compare adverse events, length of stay, surgical time, hemoglobin drop, early readmission rate and revision rate between conventional TKA (CTKA) and NAVIO RATKA. METHODS: This single-centre retrospective cohort analysis compared 230 NAVIO RATKA patients to 489 CTKA patients with a minimal follow-up of 12 months. Baseline demographic and comorbidity parameters were collected, as well as length of stay, revision rate and reason for revision, early readmission rate (< 6w) and reason for readmission, post-operative hemoglobin levels, adverse events, surgical time and operating room time. Data were compared using Mann-Whitney U test for continuous data without normal distribution and ordinal data, categorical variables were compared using the Chi-square or Fisher exact test. RESULTS: There were no clinically relevant baseline demographic or comorbidity differences between groups. CTKA had shorter length of stay than NAVIO RATKA (5.0 days vs 5.4 days, p = 0.010) but trended towards a higher reoperation rate (4.1% vs 1.7%, p = .144, n.s). No differences were found in hemoglobin drop, readmission rate or overall incidence of adverse events, but CTKA showed more hematoma formation (1.6% vs 0%, p = .044) and higher incidence of periprosthetic joint infection (PJI) (1% vs 0%, p = n.s.), whilst NAVIO RATKA showed more periprosthetic fractures and persistent wound drainage (0.4% vs 2.2%, p = .038 and 0.6% vs 4.3%, p = .001, respectively). Surgical time remained significantly longer in NAVIO RATKA during all 230 cases (87 min vs 67.6 min) and showed a continuous downward trend. CONCLUSIONS: This study further validates the usage of NAVIO RATKA as a safe method to perform TKA, with comparable short term outcomes to CTKA in terms of early revisions and adverse events. Surgeons should be mindful of the differing adverse event profile in NAVIO RATKA and adjust their patient selection accordingly to ensure optimal outcomes. In addition, surgeons using NAVIO RATKA should expect a linear learning curve and a surgical time exceeding that of CTKA. LEVEL OF EVIDENCE: Level III (therapeutic retrospective cohort study).

Fatigue-induced Landing Alterations in ACL Reconstructed Athletes after Return-to-Sport.

At the time of return-to-sport, anterior cruciate ligament reconstructed athletes still show altered neuromechanics in their injured leg during single leg hopping tasks. Part of these alterations can be magnified when these athletes are fatigued. So far, little is known whether fatigue-induced landing alterations persist after return-to-sport. Therefore, the aim of this study was to evaluate whether these alterations persist in the six months following return-to-sport. Sixteen anterior cruciate ligament reconstructed athletes performed five unilateral hop tasks before and after a fatigue protocol. The hop tasks were executed at three different time points (return-to-sport, 3 and 6 months post-return-to-sport). A 2-by-3 repeated measures ANOVA was performed to evaluate whether fatigue-induced landing alterations persisted 3 and 6 months following return-to-sport. At 6 months following return-to-sport, fatigue still induces a reduction in hamstring medialis activation and an increase in the knee abduction moment during a vertical hop with 90-degree inward rotation. Most fatigue-induced landing alterations present at the time of return-to-sport normalize after resumption of sports activities. However, a larger knee abduction moment in the injured leg after resumption of sports activities can still be observed.

A robotic-assisted simulation of kinematic alignment in TKA leads to excessive valgus and internal rotation in valgus knees.

PURPOSE: Strategies to further improve patient satisfaction after total knee arthroplasty include the introduction of new alignment philosophies and more precise instruments such as navigation and robotics. The aim of this study was to investigate the effect of a combination of image-based robotic assistance and the use of modern alignment strategies on the resulting joint line obliquity as well as femoral component rotation and to compare this between varus, neutral and valgus knees. METHODS: This retrospective study included 200 patients who received a robotic-assisted total knee arthroplasty (MAKO®, Stryker) using functional alignment between 2018 and 2020. The patients were divided into a varus (103 patients), neutral (57 patients) and valgus (40 patients) group. The intraoperatively recorded bone cuts and resulting joint line obliquity were identified and compared to values obtained with a robotic computer simulation of kinematic alignment. RESULTS: The mean femoral coronal alignment of the varus, neutral and valgus group, respectively, equalled 0.5° (± 1.1°), 1.1° (± 0.8°) and 1.6° (± 0.7°) of valgus with functional alignment and 2.1° (± 2.1°), 4.1° (± 1.7°) and 6.2° (± 1.7°) of valgus with kinematic alignment. The mean femoral axial alignment of the valgus group resulted in 0.8° (± 2.0°) of internal rotation with functional alignment and 3.9° (± 2.8°) of internal rotation with kinematic alignment. Overall, 186 knees (93%) could be balanced while respecting certain safe zones by using functional alignment as opposed to 54 knees (27% and none in the valgus group) when applying kinematic alignment. Kinematic alignment led to a combination of femoral component valgus and internal rotation of more than 3° in 22 valgus knees (55%), 10 neutral knees (18%) and 3 varus knees (3%) compared to none in each group when applying functional alignment with safe zones. CONCLUSIONS: Robotic-assisted kinematic alignment leads to a combination of excessive valgus and internal rotation of the femoral component in valgus and to a lesser extent also in neutral knees when compared with functional alignment. LEVEL OF EVIDENCE: IV.

A Simple Technique for Reconstruction of the Medial Patellofemoral Ligament With Patellar Soft-Tissue Fixation Using Synthetic Suture Tape Internal Bracing.

Recurrent patellar dislocation is most commonly treated with an isolated medial patellofemoral ligament reconstruction using autograft tissue. Harvest and fixation of these grafts have some theoretical disadvantages. With this Technical Note, we aim to describe a simple reconstruction of the medial patellofemoral ligament using high-strength suture tape with a soft-tissue fixation on the patellar side and an interference screw fixation on the femoral side, avoiding some of these possible disadvantages.

Operating room efficiency after the implementation of MAKO robotic-assisted total knee arthroplasty.

INTRODUCTION: The aim of this study was to examine if robotic-assisted total knee arthroplasty (RATKA) is cost- and time-effective in terms of implant stock and perioperative parameters, as optimizing perioperative efficiency may contribute to value-based care. MATERIALS AND METHODS: Four hundred thirty-two consecutive patients who received primary total knee arthroplasties (TKAs) from May 2017 to March 2020 in a regional hospital were included in this study. Operating room time (OR time), surgical time, number of trays, insert thickness, and length of stay (LOS) were assessed and compared for a cohort group with navigation-assisted procedures to a group with robotic-assisted procedures (MAKO, Stryker, USA). Prediction of implant size was assessed for the robotic-assisted group. The Mann-Whitney U test was used for comparisons between groups when the normality assumption was not met. Categorical variables were assessed using the Fisher's exact test. p < 0.05 was considered statistically significant. RESULTS: In the RATKA group, we noticed a significant mean reduction of 11 min in total OR time (p < 0.001), the use of thinner insert (p < 0.001), and a shorter mean length of stay of 1 day (p < 0.001). Compared to the navigation group, surgical time was not significantly longer, nor clinically relevant (0.238). In 76.9% of the robotic-assisted cases, the estimated implant size was equal to the final size and in all other cases, the preoperative implant size was oversized. CONCLUSION: The introduction of the MAKO robotic-assisted total knee arthroplasty resulted in a gain in operating room time, a thinner and more predictable insert thickness, a shorter length of stay in hospital, and less instrumentation compared to navigation-assisted procedures. Level of evidence Level III, Retrospective cohort study.

Impact of increasing total knee replacement constraint within a single implant line on coronal stability: an ex vivo investigation.

INTRODUCTION: Despite the existence of diverse total knee implant designs, few data is available on the relationship between the level of implant constraint and the postoperative joint stability in the frontal plane and strain in the collateral ligaments. The current study aimed to document this relation in an ex vivo setting. MATERIALS AND METHODS: Six fresh-frozen lower limbs underwent imaging for preparation of specimen-specific surgical guides. Specimens were dissected and assessed for joint laxity using the varus-valgus stress tests at fixed knee flexion angles. A handheld dynamometer applied tensile loads at the ankle, thereby resulting in a knee abduction-adduction moment of 10 Nm. Tibiofemoral kinematics were calculated using an optical motion capture system, while extensometers attached to medial collateral (MCL) and lateral collateral ligament (LCL) measured strain. Native joint testing was followed by four TKA designs from a single implant line-cruciate retaining, posterior stabilised, varus-valgus constrained and hinged knee (HK)-and subsequent testing after each implantation. Repeated measures linear mixed-models (p < 0.05) were used to compare preoperative vs. postoperative data on frontal plane laxity and collateral ligament strain. RESULTS: Increasing implant constraint reduced frontal plane laxity across knee flexion, especially in deep flexion (r2 > 0.76), and MCL strain in extension; however, LCL strain reduction was not consistent. Frontal plane laxity increased with knee flexion angle, but similar trends were inconclusive for ligament strain. HK reduced joint laxity and ligament strain as compared to the native condition consistently across knee flexion angle, with significant reductions in flexion (p < 0.024) and extension (p < 0.001), respectively, thereby elucidating the implant design-induced joint stability. Ligament strain exhibited a strong positive correlation with varus-valgus alignment (r2 = 0.96), notwithstanding knee flexion angle or TKA implant design. CONCLUSION: The study demonstrated that increasing the constraint of a TKA resulted in lower frontal plane laxity of the knee. With implant features impacting laxity in the coronal plane, consequentially affecting strain in collateral ligaments, surgeons must consider these factors when deciding a TKA implant, especially for primary TKA. LEVEL OF EVIDENCE: V.

The prevalence of frozen shoulder in patients with limited Dupuytren disease.

Evidence from the literature suggests an association between Dupuytren disease and frozen shoulder syndrome, both clinically and histologically. An increased tendency for fibrotic healing after repetitive microtrauma could be an underlying mechanism. However, it remains unclear how strong this association is and if only mild signs of Dupuytren disease would also increase the risk of frozen shoulder. In 61 patients, we examined the hands for signs of Dupuytren disease and the shoulders for pain and limited motion. We found a 21,7% prevalence of frozen shoulder syndrome in patients with signs of Dupuytren disease versus 13,9% in those without. The other way around, in patients with frozen shoulder syndrome the prevalence of Dupuytren disease was 50% versus 36.7% in those without frozen shoulder syndrome. These differences were not statistically significant, contrary to similar research in the literature. However, methodological issues, especially the choice of control group, may explain the differences between our findings and previous studies. We conclude that the clinical association between Dupuytren disease may not be so strong as previously thought, especially in patients with only limited signs of the disease.

The Impact of Dupuytren Disease on Recovery of Motion at the Knee after Total Knee Arthroplasty.

Background: Arthrofibrosis is a complication of total knee arthroplasty (TKA) that can lead to poor outcome. Idiopathic arthrofibrosis and Dupuytren disease (DD) have similar histological appearance. The aim of this study is to determine the influence of DD on the recovery of motion after TKAy. Methods: Patients older than 50 who underwent a TKA for primary osteoarthritis were examined 1 year later for the presence of DD. They were divided into two groups based on the presence or absence of DD. The groups were compared to each other with regard to arc of motion (AOM) of the operated knee at 6 weeks and 1 year; the need for additional measures to improve the AOM, and the effect of obesity [body mass index (BMI) > 30]. Results: The study included 61 patients of which 25 (41%) had DD. There was no difference in AOM at 6 weeks or 1 year between the two groups. Patients in the DD group required a greater number of additional measures to improve AOM. Also, non-obese patients (BMI < 30) in the DD group had lower AOM at 1 year. Conclusions: Patients in the DD group needed additional physiotherapy or manipulation under anaesthesia (MUA) to achieve the same AOM. This might indicate a possible connection between DD and post-operative stiffness of the knee. Identifying patients with DD in the pre-operative period may help recognise patients who may have difficulty in regaining AOM after TKA. Level of Evidence: Level III (Therapeutic).

Prevalence, interpretation, and management of unexpected positive cultures in revision TKA: a systematic review.

PURPOSE: Unexpected positive intraoperative cultures (UPIC) found in revision total knee arthroplasty (TKA) are difficult to interpret. Management goes along with risks for both over- and undertreating a potential periprosthetic joint infection (PJI). The objective of this systematic review was to determine the prevalence of UPIC in revision TKA surgery, evaluate the diagnostic workup process and the postoperative treatment, and assess outcome regarding re-revision rates. METHODS: Evidence was gathered from Medline (PubMed) and Embase published from January 2000 until April 2021. Nine studies with data of UPIC in revision TKA and outcome after at least 2 years of follow-up were identified. RESULTS: The calculated prevalence of UPIC in aseptic knee revision surgery was 8.32%. However, the diagnostical approach differs as well as the used criteria to confirm PJI in presumed aseptic revision surgery. The work-up generally consists of a serum C-reactive protein and Erythrocyte Sedimentation Rate, joint fluid aspiration for culture and white blood cell count and formula, and radiographic imaging. Collection of intraoperative cultures is widely used, but inconsistent in sample amount and incubation time. Once a single UPIC is found, surgeons tend to treat it in different ways. Regarding re-revision rates, the weighted arithmetic mean in the included studies was 18.45% in the unsuspected PJI group compared to 2.94% in the aseptic group. There also seems to be a trend towards higher re-revision rates when a higher number of intraoperative cultures are positive. CONCLUSION: The interpretation of UPIC in revision TKA is of utmost importance since the decision whether to treat a UPIC as an unsuspected PJI has a major impact on implant survival and re-revision rate. Different criteria are used to differentiate between unsuspected PJI and contamination in true aseptic failure, and the heterogeneity amongst the included papers impedes to state a clear recommendation, integrating not only quantitative findings, but also qualitative data such as virulence of the identified microorganism. LEVEL OF EVIDENCE: Systematic review, III.

Return to Work after Primary Total Knee Arthroplasty under the Age of 65 Years: A Systematic Review.

A growing number of patients undergoing total knee arthroplasty (TKA) is at working age and need to return to work (RTW) after surgery. The aim of this systematic review is to give an overview of the literature regarding RTW after TKA and beneficial and limiting factors influencing this process. A systematic search in four electronic databases was conducted in November 2019 to identify studies describing RTW after primary TKA in patients aged 65 years or younger. Study characteristics and data on work status before and after surgery were extracted. All studies were assessed for risk of bias. Fourteen studies published between 2009 and 2019 were included in this review, accounting for a total of 3,073 patients. The percentage of patients working after TKA ranged from 36 to 89%, and the fraction of patients working before and returning to work after surgery ranged from 40 to 98%. Mean time of RTW ranged from 7.7 to 16.6 weeks. Most important factors associated with a slower or no RTW were a more physical nature of employment and preoperative absence from work. The majority of patients undergoing TKA returned to work postoperatively. However, comparison between studies is seriously hampered by the wide variation regarding the definition and timeframe used to measure the work status. Therefore, standardized outcome measures for studies investigating RTW after TKA are warranted. We identify this review as level-I evidence (systematic review of level-I and level-II studies).

Assessment of in vivo bone activity patterns in medial mobile-bearing unicompartmental knee arthroplasty : a prospective SPECT/CT study.

AIMS: Higher osteoblastic bone activity is expected in aseptic loosening and painful unicompartmental knee arthroplasty (UKA). However, insights into normal bone activity patterns after medial UKAs are lacking. The aim of this study was to identify the evolution in bone activity pattern in well-functioning medial mobile-bearing UKAs. METHODS: In total, 34 patients (13 female, 21 male; mean age 62 years (41 to 79); BMI 29.7 kg/m2 (23.6 to 42.1)) with 38 medial Oxford partial UKAs (20 left, 18 right; 19 cementless, 14 cemented, and five hybrid) were prospectively followed with sequential 99mTc-hydroxymethane diphosphonate single photon emission CT (SPECT)/CT preoperatively, and at one and two years postoperatively. Changes in mean osteoblastic activity were investigated using a tracer localization scheme with volumes of interest (VOIs), reported by normalized mean tracer values. A SPECT/CT registration platform additionally explored cortical tracer evolution in zones of interest identified by previous experimental research. RESULTS: Significant reduction of tracer activity from the preoperative situation was found in femoral and anteromedial tibial VOIs adjacent to the UKA components. Temporarily increased osteoblastic bone activity was observed in VOIs comprising the UKA keel structure at one year postoperatively compared to the preoperative activity. Persistent higher tracer uptake was found in the posterior tibial cortex at final follow-up. Multivariate analysis showed no statistical difference in osteoblastic bone activity underneath cemented or cementless components. CONCLUSION: Well-functioning medial mobile-bearing UKAs showed distinct changes in patterns of normalized bone tracer activity in the different VOIs adjacent to the prosthetic components, regardless of their type of fixation. Compared to the preoperative situation, persistent high bone activity was found underneath the keel and the posterior tibial cortex at final follow-up, with significant reduced activity only being identified in femoral and anteromedial tibial VOIs. Cite this article: Bone Joint J 2022;104-B(1):34-44.

Neuromuscular and biomechanical landing alterations persist in athletes returning to sport after anterior cruciate ligament reconstruction.

BACKGROUND: Anterior cruciate ligament reconstructed (ACLR) athletes show increased hamstrings activation and decreased knee flexion moments (KFMs) during single leg landing tasks at time of return-to-sport (RTS). Although these landing alterations seem protective in the short term, they might become undesirable if they persist after RTS. Therefore, the main aim of this study was to investigate whether those landing alterations persist in the months following RTS. METHODS: Sixteen athletes who had an ACLR performed five unilateral landing tasks at three different time points (at RTS, and at 3 and 6 months after RTS) while KFMs and hamstrings activation were recorded. The following clinical parameters were registered: isokinetic strength of quadriceps and hamstrings, ACL return-to-sport after injury scale (ACL-RSI), Tampa scale of kinesiophobia, self-reported instability and single leg hop distance. A one-way repeated measures analysis of variance (ANOVA) was used to assess whether landing deficits changed over time. Additionally, an explorative analysis was performed to assess whether those athletes whose deficits persisted the most could be identified based on baseline clinical parameters. RESULTS: The ANOVA showed no differences in landing deficits between sessions, indicating persisting reduced KFMs and increased hamstrings activation in the injured leg compared with the contralateral leg. A significant improvement of the quadriceps concentric strength (at 120°/s), ACL-RSI score and jump distance of the single leg hop was found over time. CONCLUSIONS: Landing alterations were not resolved 6 months after RTS. Additional interventions may be needed to normalize landing alterations prior to return to sport.

Can Intraoperative Intra-Articular Loads Predict Postoperative Knee Joint Laxity Following Total Knee Arthroplasty? A Cadaver Study with Smart Tibial Trays.

Ligament balancing during total knee arthroplasty (TKA) often relies on subjective surgeon experience. Although instrumented tibial trays facilitate an objective assessment of intraoperative joint balance through quantification of intra-articular joint loads, postoperative clinical assessment of joint balance relies on passive stress tests quantifying varus-valgus joint laxity. This study aimed at correlating the intraoperative and postoperative metrics used to assess joint balance while also comparing joint loads obtained during passive assessment and active functional motions. Four experienced surgical fellows were assigned a fresh-frozen lower limb each to plan and perform posterior-stabilised TKA. An instrumented tibial insert measured intraoperative intra-articular loads. Specimens were then subjected to passive flexion-extension, open-chain extension, active squatting, and varus-valgus laxity tests on a validated knee simulator. Intra-articular loads were recorded using the instrumented insert and tibiofemoral kinematics using an optical motion capture system. A negative correlation was observed between mean intraoperative intra-articular loads and corresponding mean postoperative tibial abduction angle during laxity tests (medial: R = -0.93, p = 0.02; lateral: R = -0.88, p = 0.04); however, this was not observed for each specimen. Peak intra-articular load distribution for active squatting was lateral-heavy, contrasting to the medial-heavy distribution observed in passive intraoperative measurements, for all specimens. These aspects should be given due consideration while assessing intraoperative and postoperative joint stability following TKA.

Patient-reported outcomes after primary rotating hinge total knee arthroplasty: a multi-centre clinical cohort study.

PURPOSE: Rotating hinge prostheses for total knee arthroplasty (TKA) are mostly used in revision setting; however, evidence on the use of these constrained devices in primary setting is scarce and inconsistent. Therefore, we aimed to evaluate the functional outcomes after third-generation rotating hinge implants in primary TKA with a minimal follow-up of two years in a large dual-centre observational retrospective clinical trial. METHODS: The hospital databases of two centres were searched for primary rotating hinge arthroplasty from January 2007 to January 2015. A minimum follow-up of at least two years was assured. Patients meeting the inclusion criteria were asked to fill out two self-reported functional scores, the Oxford Knee Score (OKS) and Forgotten Joint Score (FJS), to measure the functional status of the knee. RESULTS: In total, 267 primary rotating hinge knee arthroplasties in 242 patients were performed in two centres. The three major indications were axial malalignment (valgus/varus > 15°), 87/267 (33%), persistent ligamentous instability (28%) and neuromuscular disorders (12%). 184 patients with 202 primary rotating hinge knee arthroplasties could be included that provided data of the self-reported outcome measures (OKS and FJS). A mean OKS score of 37.71 (± 9.23) and a mean FJS score of 63.65 (± 31.01) could be obtained. CONCLUSION: This large clinical study suggests that constrained devices provide the best results when treating bone-on-bone tricompartimental osteoarthritis of the knee with severe axial deviation (valgus/varus > 15°) and/or persistent ligamentous instability.

Bicruciate retaining total knee arthroplasty : results throughout history.

Approximately 20% amongst patients are dissatisfied after total knee arthroplasty (TKA). Bicruciate retaining (BCR) TKA offers superior knee kinematics and proprioception, but many surgeons abandoned its use because of complications and technical difficulties. Recently, two new BCR implant designs were introduced : Vanguard XP (Zimmer Biomet) and Journey XR (Smith&Nephew). We searched Pubmed, Limo, Embase and Cochrane, screened reference lists of eligible studies and included studies that met the inclusion criteria. We included 35 articles reporting on ten different BCR implants, including three articles presenting results of the Vanguard XP prosthesis. Unfortunately, no articles reporting on the results of the Journey XR prosthesis had been published. The BCR implants of the early 1970s showed good functional results, but a high rate of complications, mainly loosening and infections. The Townley Anatomic TKA was the first BCR implant with good clinical results, a low incidence of loosening and a high survivorship. One article of the three reporting on the Vanguard XP yielded high patient satisfaction (94%) with two revisions (1.4%). The two other articles reported three revisions (5%) after one year of follow-up and 19 revisions (13.4%) after three years of follow-up. Throughout history, the functional results of BCR TKA improved, with lessening of the complications. The short-term results of the Vanguard XP implant showed good functional results, but two out of three articles reported a high rate of loosening. Based on the results reported in this review, the use of BCR TKA is still debatable. Further high-level evidence research is necessary to assess the clinical benefit of BCR TKA.

Validated Ultrasound Speckle Tracking Method for Measuring Strains of Knee Collateral Ligaments In-Situ during Varus/Valgus Loading.

Current ultrasound techniques face several challenges to measure strains when translated from large tendon to in-situ knee collateral ligament applications, despite the potential to reduce knee arthroplasty failures attributed to ligament imbalance. Therefore, we developed, optimized and validated an ultrasound speckle tracking method to assess the in-situ strains of the medial and lateral collateral ligaments. Nine cadaveric legs with total knee implants were submitted to varus/valgus loading and divided into two groups: "optimization" and "validation". Reference strains were measured using digital image correlation technique, while ultrasound data were processed with a custom-built speckle tracking approach. Using specimens from the "optimization" group, several tracking parameters were tuned towards an optimized tracking performance. The parameters were ranked according to three comparative measures between the ultrasound-based and reference strains: R2, mean absolute error and strains differences at 40 N. Specimens from the "validation" group, processed with the optimal parameters, showed good correlations, along with small mean absolute differences, with correlation values above 0.99 and 0.89 and differences below 0.57% and 0.27% for the lateral and medial collateral ligaments, respectively. This study showed that ultrasound speckle tracking could assess knee collateral ligaments strains in situ and has the potential to be translated to clinics for knee arthroplasty-related procedures.

Metal wear debris generation in primary total knee arthroplasty: is it an issue?

More durable total knee arthroplasties (TKAs) are needed, due to the rising life expectancy, the higher activity levels of patients and the growing concerns about aseptic loosening being caused by metal hypersensitivity. In response, different hypoallergenic metal coatings have been developed for TKAs. However, possible adverse effects of these different metals (cobalt-chromium-molybdenum, zirconium, titanium and tantalum) have been neglected. The aim was to summarize the local and systemic adverse effects (including metal hypersensitivity), survival ratios, patient-reported outcome measures (PROMs) and the plasma metal ion concentrations of the different TKA coatings. A literature search on PubMed and EMBASE was performed. In total, 15 studies were found eligible. Common adverse effects of TKA were infection, loosening, pain, instability and hyper- coagulation disorders. Serious adverse effects related to TKA implants were not reported. The survival ratios and patient-reported outcome measures seem to confirm these good results. In contrast with chromium and cobalt, no significant differences were reported in the nickel, molybdenum and titanium concentrations. No significant differences between the hypoallergenic and standard TKA implants were found in terms of adverse effects, survival ratios and PROMs. A causal relationship between the common adverse effects and the different metals is unlikely. Due to the heterogeneity of the TKA implants used, no firm conclusions could be made. Further research with longer follow-up studies are needed to find possible adverse effects and differences. Thus far, the hypoallergenic implants seem to perform equal to the standard implants.

Athletes with an ACL reconstruction show a different neuromuscular response to environmental challenges compared to uninjured athletes.

BACKGROUND: Evidence suggests that neuromuscular alterations in patients with an anterior cruciate ligament reconstruction (ACLR) are rooted in neurocognitive and proprioceptive deficits. The aim of this study was to assess neuromuscular control of athletes with ACLR under increased cognitive and environmental challenges. RESEARCH QUESTION: Do athletes with ACLR show a different neuromuscular response to cognitive and environmental challenges relative to controls? METHODS: Cross-sectional study. Twenty athletes who had an ACLR (age: 23.7 ±â€¯4.3 years, 14 males, time post-surgery: 258.6 ±â€¯54 days) and twenty uninjured controls (age: 21.4 ±â€¯1.5 years, 14 males) performed a stepping down-task in four environmental conditions: no additional challenges, while performing a cognitive dual-task, while undergoing an unpredictable support surface perturbation, and with the cognitive dual-task and unpredictable perturbation combined. Muscle activations of the vastus medialis (VM), vastus lateralis, hamstrings medialis (HM), hamstrings lateralis (HL), gastrocnemius medialis, gastrocnemius lateralis (GL) and gluteus medius were recorded with surface EMG. A three-way ANOVA with main effects for group, dual-task and perturbation was used to compare muscle activations. RESULTS: Athletes with ACLR show larger HM (ES = 0.45) and HL activation (ES = 1.32) and lower VM activation (ES = 0.72), compared to controls. Athletes with ACLR show a significantly smaller increase in VM (ES = 0.69), VL (ES = 0.53) and GL activation (ES = 0.52) between perturbed and unperturbed tasks compared to controls. Furthermore, under cognitive loading a significantly larger decrease in HM activation (ES = 0.40) and (medial) co-contraction (ES = 0.75) was found in athletes with ACLR compared to controls. SIGNIFICANCE: Athletes with ACLR show an altered neuromuscular response which might represent an arthrogenic muscle response. They show less additional adaptation to perturbed tasks compared to controls, potentially as result of altered proprioceptive input. Furthermore a larger influence of increased cognitive loading on the neuromuscular control was found in athletes with ACLR, indicating that also neurocognitive limitations may contribute to altered neuromuscular control.

Good long-term survival and patient-reported outcomes after high tibial osteotomy for medial compartment osteoarthritis.

The lateral closing and medial opening wedge high tibial osteotomy can correct a varus malalignment of the knee caused by medial compartment osteoarthritis. These procedures have produced great short-term and mid-term results. As no systematic review has examined their long-term results yet, the goal of this article was to compare the results of all articles about lateral closing and medial opening wedge high tibial osteotomies, published after the year 2000, with a mean follow-up of more than 10 years. A systematic search of the Medline, Web of Science and Cochrane databases resulted in the inclusion of 30 articles. All these studies combined examined the results of 7087 high tibial osteotomies in a total of 6636 patients after a mean follow-up of more than 10 years. Primary outcome measures were the survival rate of the osteotomy, functional scores, patient satisfaction and pain scores. Secondary outcome measures were alignment correction and the identification of factors influencing the survival of the osteotomy. The 5-year, 10-year, 15-year and 20-year survival rates, respectively, ranged from 86 to 100%, 64-97.6%, 44-93.2% and 46-85.1%. The subjective scoring systems showed an improvement postoperatively that was maintained until final follow-up. The anatomical and mechanical tibiofemoral axis were, respectively, corrected to a mean of 7.3°-13.8° of valgus and 0.6°-4° of valgus. The results of the articles evaluating the influence of potential risk factors were contradictory. Despite the low quality of the available evidence, the lateral closing and medial opening wedge high tibial osteotomy seem to remain valid long-term treatment options for patients with painful varus malalignment caused by isolated medial compartment osteoarthritis of the knee. The available results indicate that the need for arthroplasty could be delayed for more than 15 years in the majority of patients. However, higher-quality studies are needed to confirm these findings. As a systematic review is assigned a level of evidence equivalent to the lowest level of evidence used from the analyzed manuscripts, the level of evidence of this systematic review is IV.