Hybridized deep learning goniometry for improved precision in Ehlers-Danlos Syndrome (EDS) evaluation.

BACKGROUND: Generalized Joint Hyper-mobility (GJH) can aid in the diagnosis of Ehlers-Danlos Syndrome (EDS), a complex genetic connective tissue disorder with clinical features that can mimic other disease processes. Our study focuses on developing a unique image-based goniometry system, the HybridPoseNet, which utilizes a hybrid deep learning model. OBJECTIVE: The proposed model is designed to provide the most accurate joint angle measurements in EDS appraisals. Using a hybrid of CNNs and HyperLSTMs in the pose estimation module of HybridPoseNet offers superior generalization and time consistency properties, setting it apart from existing complex libraries. METHODOLOGY: HybridPoseNet integrates the spatial pattern recognition prowess of MobileNet-V2 with the sequential data processing capability of HyperLSTM units. The system captures the dynamic nature of joint motion by creating a model that learns from individual frames and the sequence of movements. The CNN module of HybridPoseNet was trained on a large and diverse data set before the fine-tuning of video data involving 50 individuals visiting the EDS clinic, focusing on joints that can hyperextend. HyperLSTMs have been incorporated in video frames to avoid any time breakage in joint angle estimation in consecutive frames. The model performance was evaluated using Spearman's coefficient correlation versus manual goniometry measurements, as well as by the human labeling of joint position, the second validation step. OUTCOME: Preliminary findings demonstrate HybridPoseNet achieving a remarkable correlation with manual Goniometric measurements: thumb (rho = 0.847), elbows (rho = 0.822), knees (rho = 0.839), and fifth fingers (rho = 0.896), indicating that the newest model is considerably better. The model manifested a consistent performance in all joint assessments, hence not requiring selecting a variety of pose-measuring libraries for every joint. The presentation of HybridPoseNet contributes to achieving a combined and normalized approach to reviewing the mobility of joints, which has an overall enhancement of approximately 20% in accuracy compared to the regular pose estimation libraries. This innovation is very valuable to the field of medical diagnostics of connective tissue diseases and a vast improvement to its understanding.

Can the Current Thresholds for Synovial Cell Count and Neutrophil Percentage to Diagnose Prosthetic Joint Infection be Applied to Metal-on-Metal Rotating Hinge Total Knee Arthroplasty?

BACKGROUND: Synovial leukocyte count analysis is an important tool in the diagnosis of PJI. However, results can be poor if metallosis is present. The issue of metallosis was established for some rotating hinge knee arthroplasty designs. METHODS: This was a retrospective single-center analysis that included 108 patients who had a single-design metal-on-metal rotating hinge knee arthroplasty who underwent revision surgery and had prior synovial fluid analysis performed. The diagnostic accuracy of leukocyte count and the percentage of polymorphonuclear neutrophiles (% PMN) were investigated. RESULTS: Patients who had a PJI had a higher median leukocyte count and % PMN compared to aseptic revisions (7,905/µL (interquartile range (IQR) 2,419 to 37,400) and 85% (IQR 70.3 to 93.8) versus 450 (IQR 167 to 1,215) and 46% (IQR 28.5 to 67.4%), P < .001). The respective areas under the curves were 0.916 (95% confidence interval 0.862 to 0.970) for leukocyte count and 0.821 (95% confidence interval 0.739 to 0.902) for % PMN. We calculated an optimal cut-off value of 1,200 leukocytes/µL (Sensitivity 94.5%/specificity 75.5%) and 63% PMN (Sensitivity 85.5%/specificity 73.6%) to define PJI. Established thresholds were less sensitive, but more specific. The "infection likely" scenario of the European Bone and Joint Infection Society (EBJIS) definition was closest to the calculated thresholds. CONCLUSION: Currently used thresholds for leukocyte cell count and %PMN to define PJI were less sensitive and specific in the diagnosis of PJI in metal-on-metal RHK knees. Surgeons must consider lower cut-off values when evaluating such implants for PJI.

The Association between the Extent of the Osteoarthritic Meniscus Degeneration and Cigarette Smoking-A Pilot Study.

Background and Objectives: The negative effects of smoking on the musculoskeletal system were presented by many authors, although the relationship between smoking and osteoarthritis remains unclear. The aim of this paper was to investigate the negative effects of smoking on meniscal tissue in osteoarthritic knees by microscopic examination, by adapting the Bonar scoring system and its modifications. Materials and Methods: The study involved 34 patients with varus knees, from whom 65 samples of knee menisci were obtained. The mean age in the studied group was 65.385 years. The smoking status of the patients concluded that there were 13 smokers and 21 nonsmokers. Results: Among smokers, the mean classical Bonar score was 8.42 and the mean modified Bonar score was 6.65, while nonsmokers were characterized by scores of 8.51 and 7.35, respectively. There was a statistically significant negative correlation between the number of cigarettes and the collagen in the medial meniscus (p = 0.0197). Moreover, in the medial meniscus, the modified Bonar score correlated negatively with the number of cigarettes (p = 0.0180). Similarly, such a correlation was observed between the number of cigarettes and the modified Bonar score in the lateral meniscus (p = 0.04571). Furthermore, no correlation was identified between the number of cigarettes and the classical Bonar score in the lateral meniscus. There was a statistically significant difference in the collagen variable value between the smokers and nonsmokers groups (p = 0.04525). Conclusions: The microscopic investigation showed no differences in the menisci of smokers and nonsmokers, except for the collagen, which was more organized in smokers. Moreover, the modified Bonar score was correlated negatively with the number of cigarettes, which supports the role of neovascularization in meniscus pathology under the influence of tobacco smoking.

Constitutional alignment predicts medial ligament balancing in mechanically aligned total knee arthroplasty for varus knees.

PURPOSE: The aim of this study was to identify if constitutional alignment and preoperative radiologic parameters determined whether medial gap balancing was required in mechanically aligned total knee arthroplasty (TKA). METHODS: Two hundred and sixty three patients with 394 consecutive knees who underwent primary TKAs were retrospectively analysed in this study. Selective sequential multiple needle puncturing (MNP) was performed for medial ligament balancing when required. Constitutional alignment, which was determined using the Coronal Plane Alignment of the Knee (CPAK) classification, as well as preoperative and postoperative radiologic parameters was evaluated to identify factors which predicted the need for MNP. RESULTS: One hundred and fifty eight (40.1%) knees required medial ligament balancing with MNP. Patients who required MNP during surgery had significantly more constitutional varus, more varus preoperative mechanical Hip-Knee-Ankle angle (mHKA), smaller preoperative medial proximal tibial angle (MPTA) and a larger change in mHKA and MPTA after surgery than those who did not. Patients with constitutional varus also had a higher incidence of having had MNP to both anterior and posterior superficial medial collateral ligament (sMCL) fibres. There was no significant difference in preoperative lateral distal femoral angle (LDFA), posterior tibial slope (PTS) and varus-valgus difference (VVD) between groups. CONCLUSION: Ligament balancing using MNP was determined by constitutional alignment rather than medial soft tissue contracture. Patients with constitutional varus who had a larger medio-lateral gap difference in extension also had a higher incidence of having had MNP to both anterior and posterior sMCL fibres. LEVEL OF EVIDENCE: Retrospective comparative study, level IV.

Comparison of the clinical outcomes following total knee arthroplasty in osseous ankylosed and non-ankylosed knees using propensity-score matching.

OBJECTIVES: Few studies have compared the clinical outcomes and complications of total knee arthroplasty (TKA) in patients with and without osseous ankylosed knees. Thus, we investigated the clinical outcomes and complications of TKA in patients with osseous ankylosed knees, using a propensity-score matching method. METHODS: Thirteen knees in the osseous ankylosed-knees group and 13 knees in the non-ankylosed-knees group were included after excluding those with less than two years of follow-up or a lack of data and after propensity-score matching. The American Knee Society Score-knee (AKSS-knee), American Knee Society Score-function (AKSS-function), knee-flexion angle, knee-extension angle, knee range of motion (ROM) before and after TKA, and the number of knees with postoperative complications were evaluated as primary outcomes. RESULTS: The AKSS-knee, AKSS-function, knee-flexion angle, and knee ROM in the osseous ankylosed-knees group after TKA were significantly lower than those in the non-ankylosed-knees group. The knee-extension angle after TKA and number of knees with postoperative complications within two years were not significantly different between the two groups. CONCLUSIONS: The clinical results of TKA in patients with osseous ankylosed knees were inferior to those in patients with non-ankylosed knees.

Predictive factors for developing osteochondritis dissecans after surgery for discoid lateral meniscus are younger age and shorter meniscal width.

PURPOSE: This study aimed to identify the predictive factors for postoperative osteochondritis dissecans (OCD) in juvenile and adolescent knees with discoid lateral meniscus (DLM). METHODS: In total, 242 patients with symptomatic DLM who underwent surgery were identified. Inclusion criteria were set as follows: (1) age ≤ 17 years with an open growth plate, (2) follow-up magnetic resonance imaging, and (3) absence of preoperative OCD. Consequently, 52 patients were retrospectively investigated. Average age during surgery, body mass index (BMI), and follow-up duration were 12 years [95% confidence interval (CI) 11-13], 19.2 kg/m2 (95% CI 18.4-20.1), and 27.3 months (95% CI 20.9-33.7), respectively. Age, sex, sports activities, BMI, symptomatic OCD in other joints, postoperative rehabilitation, preoperative shift of DLM by Ahn's classification, surgical procedures (saucerization alone or with stabilization, and subtotal meniscectomy), and postoperative meniscal width were analyzed as possible predictive factors. RESULTS: Postoperatively, 42 patients without OCD and 10 with OCD were observed. In univariate analysis, younger age [odds ratio (OR) 1.5; p = 0.003], subtotal meniscectomy (OR 6.3; p = 0.027), and shorter meniscal width (OR 2.7; p = 0.005) were predictive factors for postoperative OCD. Multivariate analysis demonstrated that younger age (OR 1.6; p = 0.009) and shorter meniscal width (OR 1.5; p = 0.003) were predictive factors. CONCLUSIONS: To prevent postoperative OCD after DLM surgeries, achieving stabilization with adequate meniscal width is necessary for juvenile knees. LEVEL OF EVIDENCE: III.

The postoperative shorter meniscal width was the risk factor of lateral meniscal extrusion in the middle portion for juvenile and adolescent knees with discoid lateral meniscus.

PURPOSE: The study aim was to clarify the risk factors for postoperative meniscal extrusion in a middle portion in juvenile and adolescent knees with DLM. METHODS: Forty-six patients with symptomatic DLM who underwent surgery were retrospectively assessed. Inclusion criteria were set as follows: (1) aged ≤ 17 years with an open growth plate, (2) preoperative and postoperative follow-up MRI, and 3) reshaping surgeries comprising of saucerization alone or with meniscal repair. Average (95%CI) age during surgery, body mass index (BMI), and follow-up duration were 12 years (11-13), 19.9 kg/m2 (18.7-21.0), and 26.4 months (19.5-33.3), respectively. Age, sex, sports activities, BMI, postoperative rehabilitation, preoperative shift of DLM by Ahn's classification, surgical procedures, postoperative meniscal width of all portions, and meniscal healing were analyzed. RESULTS: Postoperatively, eight knees in the no-extrusion group and 38 knees in the extrusion group were observed. In the univariate logistic regression analysis, shorter meniscal width in a middle portion (OR = 1.580, p = 0.006), shorter minimum width of all portions (OR = 1.674, p = 0.024), and meniscal healing (OR = 0.160, p = 0.028) were the risk factors for meniscal extrusion in a middle portion. Multiple logistic regression analysis demonstrated that shorter meniscal width in a middle portion was the risk factor. CONCLUSIONS: As the clinical relevance, to prevent postoperative meniscal extrusion of the middle portion with DLM, surgeons are necessary to pay attention to maintain the adequate meniscal width for juvenile and adolescent knees. LEVEL OF EVIDENCE: III.

Fully automated patellofemoral MRI segmentation using holistically nested networks: Implications for evaluating patellofemoral osteoarthritis, pain, injury, pathology, and adolescent development.

PURPOSE: Our clinical understanding of the relationship between 3D bone morphology and knee osteoarthritis, as well as our ability to investigate potential causative factors of osteoarthritis, has been hampered by the time-intensive nature of manually segmenting bone from MR images. Thus, we aim to develop and validate a fully automated deep learning framework for segmenting the patella and distal femur cortex, in both adults and actively growing adolescents. METHODS: Data from 93 subjects, obtained from on institutional review board-approved protocol, formed the study database. 3D sagittal gradient recalled echo and gradient recalled echo with fat saturation images and manual models of the outer cortex were available for 86 femurs and 90 patellae. A deep-learning-based 2D holistically nested network (HNN) architecture was developed to automatically segment the patella and distal femur using both single (sagittal, uniplanar) and 3 cardinal plane (triplanar) methodologies. Errors in the surface-to-surface distances and the Dice coefficient were the primary measures used to quantitatively evaluate segmentation accuracy using a 9-fold cross-validation. RESULTS: Average absolute errors for segmenting both the patella and femur were 0.33 mm. The Dice coefficients were 97% and 94% for the femur and patella. The uniplanar, relative to the triplanar, methodology produced slightly superior segmentation. Neither the presence of active growth plates nor pathology influenced segmentation accuracy. CONCLUSION: The proposed HNN with multi-feature architecture provides a fully automatic technique capable of delineating the often indistinct interfaces between the bone and other joint structures with an accuracy better than nearly all other techniques presented previously, even when active growth plates are present.

Hyperdiluted calcium hydroxylapatite for skin laxity and cellulite of the skin above the knee: A pilot study.

Despite an increasing request for skin rejuvenation above the knee, very few treatment options have been reported in literature. To evaluate the efficacy and safety of 1:4 hyperdiluted calcium hydroxylapatite (CaHA) in the treatment of skin laxity and dimples of the skin above the knees. A retrospective evaluation of hyperdiluted CaHA treatment for skin laxity and dimples above the knee was performed. Efficacy was classified as blinded evaluation of pre (T0) and 3-month post-treatment (T1) photographs by three investigators according to the validated knee cellulite severity score (KCSS) and patient satisfaction. Safety was evaluated through pain scores and adverse events evaluation. A significant reduction of KCSS at T1, as compared to T0, mainly in subjects with lower KCSS at T0, was observed (P < .05). All blinded assessments resulted in a correct identification of T0 and T1 pictures and evaluations of all investigators were found to be consistent and reliable. All patients were satisfied. Only minor adverse events (swelling, erythema, bruising, and skin irregularities) were reported, lasting 2 to 3 weeks after treatment. Our preliminary results highlight the efficacy and safety of hyperdiluted CaHA in the treatment of skin laxity and cellulite above the knees.

[Common peroneal nerve "pre-release" to avoid nerve palsy in total knee arthroplasty for severe valgus deformities].

Objective: To investigate the clinical efficacy of common peroneal nerve "pre-release" to avoid nerve palsy in total knee arthroplasty for severe valgus deformities. Methods: Twenty patients (22 knees) with severe valgus deformities were prospectively and continuously included in Fujian Province Hospital from January 2010 to January 2016. Medial parapatellar arthrotomy, femoral distal resection using the intramedullary cutting guide with 3° to 5° of valgus and the common peroneal nerve "pre-release" was performed, the patella was routinely resurfaced. A common peroneal nerve checking was performed (LSUHSC system), then, these outcomes were collected independently using visual analogue scale (VAS) of pain, Knee Society Score (KSS), Hospital for Special Surgery Knee Score (HSS), range of motion of knees (ROM), femorotibial angle (FTA), hip-knee-ankle angle (HKA), condylar-hip angle (CHA), plateau- ankle angle (PAA). The paired t test was used to compare the data before and after the operation. Results: Patients were followed up for 18 to 55 (mean, (38±8) months). According to Krackow's classification, all cases were typed Ⅱ. All the patients had a completely normal motor (grade 5) and sensory (LSUHSC score was 5) nerve function of common peroneal nerve postoperatively. No decrease or loss in muscle strength and cutaneous sensation associated with common peroneal nerve was found. The VAS of pain, KSS, HSS, ROM, HKA, CHA, and PAA were all improved after the operation when compared with those before the operation (t=21.602, -70.238, -82.455, -20.560, 16.058, 9.682, 3.439, all P<0.05). The alignment of lower limbs was corrected basically, and the FTA decreased from 31.7°±8.0° before operation to 5.0°±2.0° at the last follow-up, the differences was statistically significant (t=16.725, P<0.05). No common peroneal nerve palsy and transient or late-onset palsy occurred, and no revision was needed for instability during the follow-up in all the patients. Conclusion: Common peroneal nerve "pre-release" for severe valgus knees may be an effective method in protecting the nerve.

Cartilage loss in radiographically normal knees depends on radiographic status of the contralateral knee - data from the Osteoarthritis Initiative.

OBJECTIVE: To test whether radiographically normal knees with contralateral radiographic knee osteoarthritis (OA), but without contralateral trauma history, display greater cartilage thickness loss than knees from subjects with bilaterally radiographically normal knees. METHODS: 828 radiographically normal knees (Kellgren Lawrence grade [KLG] 0) from the Osteoarthritis Initiative [OAI] were studied; 150 case knees displayed definite radiographic knee OA (KLG ≥ 2) contralaterally, and had MRI double echo steady state (DESS) images available at 12 and 48 month follow-up. 678 reference knees displayed KLG0 at the contralateral side. Cartilage thickness change was determined in femorotibial subregions and location-independent cartilage thinning scores were computed. Case and reference knees were compared using ANCOVA. RESULTS: Of the 150 KLG0 case knees, 108 had a contralateral KLG2 knee (50 without, and 58 with joint space narrowing [JSN]), 31 a KLG3 and 11 a KLG4 knee. The cartilage thinning score tended to be greater in case than reference knees; the cartilage thinning score in KLG0 case knees with contralateral radiographic JSN (-858 µm; [95% confidence interval -1016, -701 µm]) was significantly greater (P = 0.0012) than that in bilaterally KLG0 reference knees (-634 µm; [-673, -596 µm]), whereas KLG0 knees with contralateral KLG2 without JSN only showed relatively small thinning scores (-530 µm, [-631, -428 µm]). Region-specific analysis suggested greater rates of cartilage loss in case than in reference knees in the lateral, rather than medial, femorotibial compartment. CONCLUSIONS: Radiographically normal knees with contralateral JSN may serve as a human model of early OA, for testing disease modifying drugs in clinical trials designed to prevent cartilage loss before the onset of radiographic change. CLINICALTRIALS. GOV IDENTIFICATION: NCT00080171.

Reference values for gait temporal and loading symmetry of lower-limb amputees can help in refocusing rehabilitation targets.

BACKGROUND: The literature suggests that optimal levels of gait symmetry might exist for lower-limb amputees. Not only these optimal values are unknown, but we also don't know typical symmetry ratios or which measures of symmetry are essential. Focusing on the symmetries of stance, step, first peak and impulse of the ground reaction force, the aim of this work was to answer to three methodological and three clinical questions. The methodological questions wanted to establish a minimum set of symmetry indexes to study and if there are limitations in their calculations. The clinical questions wanted to establish if typical levels of temporal and loading symmetry exist, and change with the level of amputation and prosthetic components. METHODS: Sixty traumatic, K3-K4 amputees were involved in the study: 12 transfemoral mechanical knee users (TFM), 25 C-leg knee users (TFC), and 23 transtibial amputees (TT). Ninety-two percent used the Ossur Variflex foot. Ten healthy subjects were also included. Ground reaction force from both feet were collected with the Novel Pedar-X. Symmetry indexes were calculated and statistically compared with regression analyses and non-parametric analysis of variance among subjects. RESULTS: Stance symmetry can be reported instead of step, but it cannot substitute impulse and first peak symmetry. The first peak cannot always be detected on all amputees. Statistically significant differences exist for stance symmetry among all groups, for impulse symmetry between TFM and TFC/TT, for first peak symmetry between transfemoral amputees altogether and TT. Regarding impulse symmetry, 25% of TFC and 43% of TT had a higher impulse on the prosthetic side. Regarding first peak symmetry, 59% of TF and 30% of TT loaded more the prosthetic side. CONCLUSIONS: Typical levels of symmetry for stance, impulse and first peak change with the level of amputation and componentry. Indications exist that C-leg and energy-storage-and-return feet can improve symmetry. Results are suggestive of two mechanisms related to sound side knee osteoarthritis: increased impulse for TF and increased first peak for TT. These results can be useful in clinics to set rehabilitation targets, understand the advancements of a patient during gait retraining, compare and chose components and possibly rehabilitation programs.

Mortality and Implant Survival With Simultaneous and Staged Bilateral Total Knee Arthroplasty Experience From the Australian Orthopaedic Association National Joint Replacement Registry.

BACKGROUND: Total knee arthroplasty (TKA) is an effective procedure for relieving pain and restoring function in osteoarthritis, with a significant proportion of patients having severe disease bilaterally. However, although there are differences in patient selection criteria for bilateral procedures, there is no consensus regarding the optimal timing for bilateral TKA. The aim of this study was to compare rates and causes of revision and 30-day mortality between simultaneous and staged bilateral TKA using data from the Australian Orthopaedic Association National Joint Replacement Registry. METHODS: Data for over 36,000 bilateral TKAs were collected from September 1999 to December 2015. Rates and causes of revision and 30-day mortality rates were obtained for simultaneous bilateral and staged procedures with intervals of 1 day-6 weeks, 6 weeks-3 months, and 3-6 months. Yearly cumulative percent revision or cumulative percent survival with 95% confidence intervals calculated using the Kaplan-Meier method and adjusted hazard ratios were used for comparisons. RESULTS: There was no significant difference between revision rates or reasons for revision between staged bilateral and simultaneous TKA (hazard ratio 1.09 [95% confidence interval {CI} 0.85-1.40; P = .511] for 1 day-6 weeks, 0.93 [95% CI 0.77-1.14; P = .494] for 6 weeks-3 months, and 1.10 [95% CI 0.98-1.23; P = .115] for 3-6 months). The most common reasons for revision were loosening/lysis and infection. The 30-day mortality rates were lower in the 6 weeks-3 months group than simultaneous bilaterals (P = .007). CONCLUSION: This study demonstrates that simultaneous and staged bilateral TKA have similar rates of revision over the medium term but that 30-day mortality is reduced in the 6 weeks-3 months group.

Self-Regulation and Academic Measures Across the Early Elementary School Grades: Examining Longitudinal and Bidirectional Associations.

This study evaluated the association between children's (N = 301) self-regulation and math and reading achievement in kindergarten, first grade, and second grade. Children's self-regulation was assessed using the Head-Toes-Knees-Shoulders (HTKS) task (involving control of gross body movements) and a computerized continuous performance task (CPT; assessing primarily inhibitory control) in kindergarten, first grade, and second grade. Research findings: Based on cross-lagged structural equation panel models, HTKS task performance positively predicted later math and reading achievement. Math achievement significantly and positively predicted later HTKS and CPT scores. Earlier math and reading achievement moderated the association between CPT scores and later math and reading achievement; inhibitory control-based self-regulation assessed with the CPT predicted higher math or reading achievement in subsequent grades for children with lower math or reading achievement in prior grades. Performance on the CPT moderated the paths from HTKS scores to later reading achievement; behavioral self-regulation assessed with the HTKS task predicted higher reading achievement in subsequent grades for children with low or average CPT performance in prior grades. Practice: Results from this study have the potential to inform targeted academic interventions focused on enhancing self-regulation in school contexts. The findings highlight the utility of assessing multiple measures of self-regulation.

Clinical outcomes after multiligament injured knees: medial versus lateral reconstructions.

PURPOSE: The purpose of this study was to analyse the clinical outcomes of multiligament injured knees with respect to the medial collateral ligament and posteromedial corner (PMC) repair or reconstruction versus the posterolateral corner (PLC) reconstruction in patients operated according to a codified surgical protocol. METHODS: Patients were divided into two groups depending on whether PMC or PLC was injured. Cruciate ligaments as well as PMC or PLC were reconstructed/repaired in a one-stage procedure. At minimum of 1-year follow-up, objective and subjective International Knee Documentation Committee (IKDC) forms, Lysholm score and sports activity level were recorded. RESULTS: Thirty-nine patients with a median follow-up time of 57 months (range 12-129) were reviewed. No significant difference was found for functional scores between acute PMC and PLC subgroups. In Group PLC, subjective outcomes tend to be better in the acute than in chronic reconstruction subgroup. CONCLUSIONS: A one-stage protocol with early surgery rather than delayed reconstruction produced better clinical outcomes whatever the injured collateral ligament, medial or lateral. In the future, early and chronic reconstructions as well as each injury pattern should be considered as separate entities in studies on multiple ligament injured knees to reach a better level of evidence. LEVEL OF EVIDENCE: IV.

Does Achieving High Flexion Increase Polyethylene Damage in Posterior-Stabilized Knees? A Retrieval Study.

BACKGROUND: Increased range of motion to higher degrees of flexion following total knee arthroplasty has been postulated to increase implant damage and revision rates, even in designs modified to accommodate high flexion. METHODS: We examined posterior-stabilized and high-flexion retrieved tibial inserts to look for differences in polyethylene surface damage with light microscopy and 3D deviation with laser scanning between inserts from patients who achieved a high degree of flexion (≥120° postoperatively) and inserts from patients who did not reach a high degree of flexion. RESULTS: No differences were found in damage scores on the articular and backside surfaces, except for abrasion in the posterior articular regions, or in 3D deviations between patients who reached a high degree of flexion and patients who did not. These results were independent of the reason for revision. CONCLUSION: In our series, reaching a high degree of flexion did not influence surface damage or 3D deviation of the polyethylene inserts.

A Comparative Study on the Long-Term Outcome of Total Knee Arthroplasty Performed for Knees Stiff in Extension and Those Stiff in Flexion.

BACKGROUND: Patients with chronic stiff knee with extremely restricted arc of motion (AOM ≤ 20°) may present with stiffness either in extension (stiff in extension [SE]) or in flexion (stiff in flexion [SF]). The difference in the functional outcome after total knee arthroplasty between these 2 groups has not been elaborated in literature. METHODS: We retrospectively analyzed 96 patients (115 knees), who had undergone total knee arthroplasty between January 1990 and December 2010 for stiff or spontaneously ankylosed knees (AOM ≤ 20°). This included 51 knees in SE group and 64 knees in SF group. RESULTS: The average duration of follow-up was 9.7 years (2-17.5 years). The total AOM improved from an average of 10.9° ± 7.4° preoperatively to 86.5° ± 13.5° postoperatively in SE group and 8.7° ± 6.8° to 92.2° ± 16.8° in the SF group. The mean Knee Society Score in the SE group improved from 23.2 ± 5.7 preoperatively to 74.1 ± 8.9 postoperatively and that of SF group from 14 ± 5.2 to 71.2 ± 12.5. At 3 months follow-up, Knee Society Score for SE group were higher than that for SF group (P = .03). This difference was not noted beyond 1 year. Complications were noted in 24 (20.9%) knees-10 (23.5%) in SE group and 14 (21.9%) in SF group. CONCLUSION: The maximum mean AOM achieved was higher in SF group but the incidence of residual flexion contracture was also higher as compared to SE group. The long-term functional outcome scores in SE and SF groups are similar.

Investigation on Inter-Limb Coordination and Motion Stability, Intensity and Complexity of Trunk and Limbs during Hands-Knees Crawling in Human Adults.

This study aimed to investigate the inter-limb coordination pattern and the stability, intensity, and complexity of the trunk and limbs motions in human crawling under different speeds. Thirty healthy human adults finished hands-knees crawling trials on a treadmill at six different speeds (from 1 km/h to 2.5 km/h). A home-made multi-channel acquisition system consisting of five 3-axis accelerometers (ACC) and four force sensors was used for the data collection. Ipsilateral phase lag was used to represent inter-limb coordination pattern during crawling and power, harmonic ratio, and sample entropy of acceleration signals were adopted to depict the motion intensity, stability, and complexity of trunk and limbs respectively. Our results revealed some relationships between inter-limb coordination patterns and the stability and complexity of trunk movement. Trot-like crawling pattern was found to be the most stable and regular one at low speed in the view of trunk movement, and no-limb-pairing pattern showed the lowest stability and the greatest complexity at high speed. These relationships could be used to explain why subjects tended to avoid no-limb-pairing pattern when speed was over 2 km/h no matter which coordination type they used at low speeds. This also provided the evidence that the central nervous system (CNS) chose a stable inter-limb coordination pattern to keep the body safe and avoid tumbling. Although considerable progress has been made in the study of four-limb locomotion, much less is known about the reasons for the variety of inter-limb coordination. The research results of the exploration on the inter-limb coordination pattern choice during crawling from the standpoint of the motion stability, intensity, and complexity of trunk and limbs sheds light on the underlying motor control strategy of the human CNS and has important significance in the fields of clinical diagnosis, rehabilitation engineering, and kinematics research.

Stand up: comparison of two electrical screed levelling machines to reduce the work demands for the knees and low back among floor layers.

Electrical screed levelling machines are developed to reduce kneeling and trunk flexion of sand-cement-bound screed floor layers. An observational intervention study among 10 floor layers was performed to assess the differences between a self-propelled and a manually moved machine. The outcome measures were work demands, production time, perceived load, discomfort and applicability. Compared to the self-propelled machine, the duration of kneeling (∆13 min; p = 0.003) and trunk flexion (∆12 min; p < 0.001) was shorter using the manually moved machine, and the duration of pushing and pulling increased (∆39 min; p < 0.001). No significant or relevant differences were found for production time, perceived load and discomfort. Nine out of ten floor layers found the manually moved machine applicable and three out of ten found the self-propelled machine applicable. When compared with the traditional manner of floor laying, both electrical machines reduced the exposure towards kneeling and trunk flexion. Practitioner Summary: Electrical machines may help to reduce high physical work demands on floor layers. A manually moved machine is better applicable for the installation of screed floors in residences with smaller floor areas. A self-propelled machine is better applicable on large floor areas with a minimum width of 4 m.