The Influence of Sports-Related Concussion on Cognition and Landing Biomechanics in Collegiate Athletes.

Injury surveillance data indicate that collegiate athletes are at greater risk for lower extremity (LE) injuries following sports-related concussion (SRC). While the association between SRC and LE injury appears to be clinically relevant up to 1-year post-SRC, little evidence has been provided to determine possible mechanistic rationales. Thus, we aimed to compare collegiate athletes with a history of SRC to matched controls on biomechanical and cognitive performance measures associated with LE injury risk. Athletes with a history of SRC (n = 20) and matched controls (n = 20) performed unanticipated bilateral land-and-cut tasks and cognitive assessments. Group-based analyses (ANOVA) and predictive modeling (C5.0 decision tree algorithm) were used to compare group differences on biomechanical and cognitive measures. Collegiate athletes with a history of SRC demonstrated approximately six degrees less peak knee flexion on both dominant (p = 0.03, d = 0.71) and nondominant (p = 0.02, d = 0.78) limbs during the land-and-cut tasks compared to controls. Verbal Memory, knee flexion, and Go/No Go total score (C5.0 decision tree algorithm) were identified as the strongest indicators of previous SRC injury history. Reduced knee flexion during sport-specific land-and-cut tasks may be a mechanism for increased LE injury risk in athletes with a history of SRC. There appears to be multiple biomechanical and cognitive predictors for identifying previous SRC in collegiate athletes, providing evidence to support a multifactorial SRC management strategy to reduce future injury risk.

Measured distance from posterior tibia to popliteal artery increases with flexion and subluxation of the knee.

Purpose: Popliteal artery laceration is a devastating complication in total knee arthroplasty (TKA). Its anatomic position relative to the tibia has been studied using ultrasound or magnetic resonance imaging. This is the first study performed in a laboratory using radiographic measurements to determine if increased flexion and subluxation of the knee increase the distance between the tibia and popliteal artery. Methods: The femoral artery was infused with radiopaque dye in six cadavers. The knee was placed in two different degrees of flexion and three of subluxation. The radiographic distance between standardized markers in the posterior tibia and popliteal artery was measured. Results: The average distance from the tibial peg to the popliteal artery at 90° of flexion increased from 0% to 50% to 100% subluxation. The increase was statistically significant (Friedman test p = 0.016). The contrast between neutral and 100% subluxation was statistically significant (Sign test p = 0.031). At 115° flexion, average distance from the peg to popliteal artery significantly increased as subluxation increased (Friedman test p = 0.05). In three specimens, at 115° of flexion and 100% subluxation, a line perpendicular to the axis of the tibia, failed to intersect the popliteal artery. The measured distance increased from 90° to 115° of flexion at a given degree of subluxation, but this difference did not reach statistical significance. Conclusions: Increasing flexion and subluxation of the tibia results in increasing distance between the cut plane of the tibial plateau and popliteal artery and decreases risk of laceration. Level of Evidence: Not applicable.

Association Between Knee Flexor Strength and Preservation of the Tibial Attachment of the Sartorial Fascia During Hamstring Tendon Harvest.

Background: During anterior cruciate ligament (ACL) reconstruction, there are various autograft options. Donor-site morbidity is an important consideration while deciding the type of the autograft. Gracilis and semitendinosus autografts are commonly used in ACL reconstruction, resulting in weakness of the hamstring muscle. Hypothesis: We hypothesized that if we preserved the tibial insertion site of the sartorial fascia (SF) during hamstring tendon harvest, there would be better recovery of knee flexor strength. Study Design: Case-control study; Level of evidence, 3. Methods: In this retrospective study, 34 patients (aged 20-59 years) underwent ACL reconstruction using hamstring tendon autograft with 2 different incision techniques on the SF. The tibial attachment site of the SF was preserved in 17 patients. The insertion site of the muscle was incised transversely in 17 patients. The follow-up duration was ≥2 years. Patients were recalled to the institute for examination and muscle strength assessment. The results were compared between the groups in terms of flexor and extensor knee isokinetic muscle strength at 60 and 180 deg/s. Results: There was no statistical difference between the groups in terms of age, sex, or body mass index. When compared with patients whose SF attachment site was incised, patients with a preserved SF tibial insertion were found to have a higher flexion peak torque at the angular speed of 180 deg/s (P < 002). No statistically significant difference was noted at 60 deg/s. Conclusion: During collection of gracilis and semitendinosus autografts, preserving the SF tibial attachment site was associated with better knee flexion peak torque.

Outcomes of Early Versus Delayed Manipulation Under Anesthesia for Stiffness Following Total Knee Arthroplasty: A Systematic Review and Meta-Analysis.

BACKGROUND: Stiffness following total knee arthroplasty (TKA) is often treated with manipulation under anesthesia (MUA). However, there is debate regarding the timing of MUA, with many recommending against MUA beyond 3 months after TKA. Therefore, the purpose of this systematic review was to evaluate the functional and clinical outcomes of early versus delayed MUA for stiffness following TKA. METHODS: A search following Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines was performed in the PubMed, Embase, Scopus, and Cochrane databases in November 2023. Data regarding study characteristics, demographics, knee flexion and extension, patient-reported outcomes, complications, and revisions were collected. A quality assessment was performed using the Methodological Index for Non-randomized Studies. Included were 14 studies analyzing 13,445 knees, 72.1% of which underwent early MUA and 27.8% of which underwent delayed MUA. Of the 14 studies, 10 defined early MUA as being performed within 3 months of the index TKA. RESULTS: Pre-MUA and post-MUA knee flexion for the early/delayed groups was 71.3°/77.9° and 103.0°/96.1°, respectively. Upon meta-analysis, pre-MUA knee flexion was significantly higher in the delayed group (P = .003), whereas post-MUA flexion was similar in both groups (P = .36). The mean gain in knee flexion for the early and delayed groups was 32.0°/19.2°. The surgical complication and revision TKA rates for the early and delayed groups were 4.9%/10.3% and 5%/9%, respectively. A meta-analysis found the risk of surgical or medical complications and revision TKA to be significantly higher in the delayed MUA group (P < .00001 and = .002, respectively). CONCLUSIONS: Although post-MUA knee flexion was similar in patients undergoing early and delayed MUA following TKA, the mean gain in flexion for early patients was nearly double that of delayed patients. Delayed patients also had significantly higher risks of surgical or medical complications and revision TKA following MUA.

Patient height is a predictive factor for good postoperative knee flexion after cruciate-retaining total knee arthroplasty with GRADIUS design.

BACKGROUND: A gradually reducing radius (GRADIUS) design implant can facilitate a smooth transition from stability through full range of motion in total knee arthroplasty (TKA). Nonetheless, patient-specific factors associated with good knee flexion remain unclear. OBJECTIVE: This study aimed to determine the factors associated with good knee flexion after cruciate-retaining TKA with a GRADIUS prosthesis in an Asian population. METHODS: This retrospective study included 135 patients that were stratified according to postoperative knee flexion angle (KFA) into Group F (⩾ 120∘; 85 patients [63.2%]) and Group NF (< 120∘; 50 patients [36.8%]). RESULTS: Patients in Group F were taller and had a lower body mass index (BMI) smaller preoperative hipkneeankle angle and better preoperative extension and flexion angle than Group NF patients. The multivariable analysis revealed that patients' height (odds ratio [OR]: 1.07, P= 0.0150), BMI (OR: 0.85, P= 0.0049), and preoperative flexion angle (OR: 1.06, P= 0.0008) predicted good KFA. The ROC curve analysis showed that the cutoff values of a good KFA were height 155.1 cm, BMI 22.1 kg/m2, and preoperative KFA 120∘. CONCLUSIONS: Patient height, BMI, and preoperative KFA were independent factors affecting good postoperative KFA in patients of Asian descent who underwent cruciate-retaining TKA with a GRADIUS design.

Comparative analysis of surgical treatment modalities for a popliteal pterygium: a meta-analysis.

INTRODUCTION: Popliteal pterygium syndrome is a rare congenital disorder characterized by orofacial, cutaneous, musculoskeletal, and genital anomalies. The popliteal pterygium (PP) affects ambulation due to severe knee flexion contracture and equinovarus deformities. Surgical treatment aims to correct these deformities while preserving limb sensibility. However, due to its rarity, surgical guidelines are lacking. MATERIALS AND METHODS: A meta-analysis according to PRISMA guidelines was conducted to summarize and compare surgical methods for PP. 183 paper were identified in PubMed and data from 32 articles were analyzed, including patient demographics, treatment modalities (Ilizarov fixator, femoral osteotomy, skin/soft tissue procedures, hamstring release, nerve surgery, and amputation), pre- and post-operative abilities to walk, knee joint parameters, complications, and recurrent contractions. RESULTS: Among 58 patients (87 limbs), Ilizarov fixator demonstrated improved knee and ankle mobility postoperatively, but showed a relatively high surgical session count and complication rates. Femoral osteotomy achieved successful knee posture correction with fewer sessions and no complications. Isolated skin/soft tissue procedures improved flexion contracture and mobility, though they required several procedures. Hamstring release achieved notable contracture reduction but also necessitated multiple interventions. Nerve surgery and amputation had limited data, warranting further investigation. CONCLUSION: The management of PP demands a comprehensive approach, considering individual patient characteristics and treatment outcomes. While different surgical modalities offer distinct benefits, a classification or guideline to treat this deformity is still lacking. Further research is essential to validate findings, refine treatment approaches, and enhance the quality of life for individuals with PP.

Comparing Knee Kinetics and Kinematics in Healthy Individuals and Those With Knee Osteoarthritis, With and Without Flat Feet.

Individuals with knee osteoarthritis (KOA) and flat feet are more likely to experience increased pain and cartilage damage. This study aimed to investigate the knee kinetics, kinematics, pain, and physical function in individuals with moderate symptomatic KOA, in comparison to asymptomatic control participants. Thirty volunteers with moderate KOA (with flat feet n = 15, with normal feet n = 15) and 30 asymptomatic people (with flat feet n = 15, with normal feet n = 15) were evaluated. The knee adduction angular impulse, knee flexion moment, knee flexion angular impulse, and knee flexion angle were measured during level walking. The pain was assessed in patients with KOA. The study found that individuals with KOA had a significant increase in the knee adduction angular impulse compared with the asymptomatic people (P < .05). The KOA with flat feet group had significantly lower knee flexion moment, knee flexion angular impulse, and knee flexion angle values than the KOA with normal feet group (P < .05). Furthermore, the KOA with flat feet group had a higher pain score than the KOA with normal feet group. Individuals with osteoarthritis and flat feet had lower knee flexion moments which may indicate reduced knee force exerted through compensatory mechanisms. Despite this reduction, they reported significantly higher levels of pain compared with those without flat feet, a finding that warrants further investigation in future studies.

The Effect of Variations in Knee and Hip Angles on Electromyographic Activity of the Hamstrings and Related Muscles During the Nordic Hamstring Exercise.

Background: The benefit of performing the Nordic Hamstring Exercise (NHE) on an inclined board has been described, however, isometric hamstring activation in different knee and hip angles has not yet been thoroughly explored. Purpose: This study investigated the effect of variations in knee and hip angles during the isometric performance of the NHE on electromyographic activity of the hamstring muscles. Study design: Crossover study. Methods: Thirteen male volunteers performed isometric contractions during the NHE with the knee (30°, 50°, 60°) and the hip (0°, 30°, and 45°) in various angles of flexion on a leg support platform which was inclined at 30°. An electrical goniometer was used to monitor the knee and hip joint angles during 5-s isometric contractions. A multivariate analysis of variance with repeated measures was used to compare normalized electromyographic values of each muscle across different knee and hip angles, followed by pairwise comparisons. Results: The electromyographic activity of the biceps femoris, semitendinosus, and semimembranosus at a knee angle of 30° and hip angle of 0° were significantly higher than those observed with a knee angle of 50° and hip angle of 0°, or a knee angle of 60° and hip angle of 0° (p<0.05). The electromyographic activity of the semimembranosus at a knee angle of 60° and hip angle of 45° was significantly higher than values obtained with knee and hip angles of 60° and 0°, respectively (p<0.05). Conclusions: The results indicate that using a knee flexion of 30° and a hip flexion of 0°, while isometrically performing the NHE on a platform inclined at 30°, may optimize electromyographic activity of the hamstrings. Level of Evidence: 3.

Influence and Clinical Significance of Knee Flexion Angle on the Anatomic Course of the Common Peroneal Nerve in the Posterolateral Corner of the Knee Joint.

Background: Detailed knowledge of the anatomic course of the common peroneal nerve (CPN) is crucial for the surgical treatment of the posterolateral corner (PLC) of the knee. Purpose: To investigate the relationship of the CPN to the PLC of the knee at different flexion angles. Study Design: Descriptive laboratory study. Methods: Ten healthy volunteers were recruited to undergo magnetic resonance imaging (MRI) of the knee joint at knee flexion angles of 0°, 30°, 60°, 90°, and 120°. MRI scans at 3 levels (joint line, tibial cut, and fibular tip) were evaluated to determine (1) the distance from the CPN to the PLC and (2) the distances between the CPN and the anterior-posterior and medial-lateral tibial axes. A 3-dimensional model of the knee joint created from MRI scans of a single participant was used to simulate the creation of a fibular tunnel for PLC reconstruction and investigate the relationship between the CPN, fibular tunnel, and guide pin. Results: The CPN moved posteromedially with increased knee flexion angles. As the flexion angle increased, the distances from the CPN to the anterior-posterior axis and the PLC increased significantly, while the distance to the medial-lateral axis decreased significantly at all 3 measurement levels. The distances between the CPN and anterior-posterior and medial-lateral axes were significantly different among the different knee flexion angles at the different measurement levels. There were no significant differences in the mean distance from the CPN to the posterolateral border of the tibial plateau between 0° and 30° of flexion at the fibular tip level (P = .953). There were statistically significant differences in the distance from the CPN to the PLC of the tibial plateau at the different measurement levels. The 3-dimensional model demonstrated that the position of the CPN relative to the guide pin and the bone tunnel undergoes changes during knee flexion. Conclusion: Changes in the knee flexion angle produced corresponding changes in the course of the CPN on the posterolateral aspect of the knee joint. The CPN moved posteromedially with increased knee flexion angles. Clinical Relevance: Increasing the knee flexion angle during PLC reconstruction can effectively avoid direct injury of the CPN.

Distal femoral osteotomy and patellar tendon advancement for the treatment of crouch gait in patients with bilateral spastic cerebral palsy.

BACKGROUND: Crouch gait, or flexed knee gait, represents a common gait pattern in patients with spastic bilateral cerebral palsy (CP). Distal femoral extension and/or shortening osteotomy (DFEO/DFSO) and patellar tendon advancement (PTA) can be considered as viable options when knee flexion contractures are involved. Better outcomes have been reported after a combination of both, independently of the presence of knee extensor lag. In this study, we evaluated the clinical and kinematic outcomes of these procedures. PATIENTS AND METHODS: We reviewed a cohort of 52 limbs (28 patients) who were treated for crouch gait by DFEO/DFSO alone (group 1, n = 15) or DFEO/DFSO + PTA (group 2, n = 37) as a part of single event multilevel surgery (SEMLS). The mean age at surgery was 14 years, and the mean follow-up time was 18 months. The physical examination data and three-dimensional standardized gait analysis were collected and analyzed before the surgery and postoperatively. RESULTS: Overall knee range of motion improved in all limbs. The knee flexion decreased significantly in both groups at initial, mid, and terminal stance. Hip flexion significantly decreased in mid-stance for limbs in group 2. Both clinical and gait parameters were most improved in limbs who underwent DFEO/DFSO + PTA. Increased pelvic tilt was observed in both groups after surgery. CONCLUSION: Although DFEO/DFSO alone was successful in correcting knee flexion contractures, PTA has helped to improve knee extensor lag and knee extension during gait. LEVEL OF EVIDENCE: Therapeutic level IV.

Minimal clinically important change of knee flexion in people with knee osteoarthritis after non-surgical interventions using a meta-analytical approach.

BACKGROUND: Minimal clinically important change (MCIC) represents the minimum patient-perceived improvement in an outcome after treatment, in an individual or within a group over time. This study aimed to determine MCIC of knee flexion in people with knee OA after non-surgical interventions using a meta-analytical approach. METHODS: Four databases (MEDLINE, Cochrane, Web of Science and CINAHL) were searched for studies of randomised clinical trials of non-surgical interventions with intervention duration of ≤ 3 months that reported change in (Δ) (mean change between baseline and immediately after the intervention) knee flexion with Δ pain or Δ function measured using tools that have established MCIC values. The risk of bias in the included studies was assessed using version 2 of the Cochrane risk-of-bias tool for randomised trials (RoB 2). Bayesian meta-analytic models were used to determine relationships between Δ flexion with Δ pain and Δ function after non-surgical interventions and MCIC of knee flexion. RESULTS: Seventy-two studies (k = 72, n = 5174) were eligible. Meta-analyses included 140 intervention arms (k = 61, n = 4516) that reported Δ flexion with Δ pain using the visual analog scale (pain-VAS) and Δ function using the Western Ontario and McMaster Universities Osteoarthritis Index function subscale (function-WOMAC). Linear relationships between Δ pain at rest-VAS (0-100 mm) with Δ flexion were - 0.29 (- 0.44; - 0.15) (ß: posterior median (CrI: credible interval)). Relationships between Δ pain during activity VAS and Δ flexion were - 0.29 (- 0.41, - 0.18), and Δ pain-general VAS and Δ flexion were - 0.33 (- 0.42, - 0.23). The relationship between Δ function-WOMAC (out of 100) and Δ flexion was - 0.15 (- 0.25, - 0.07). Increased Δ flexion was associated with decreased Δ pain-VAS and increased Δ function-WOMAC. The point estimates for MCIC of knee flexion ranged from 3.8 to 6.4°. CONCLUSIONS: The estimated knee flexion MCIC values from this study are the first to be reported using a novel meta-analytical method. The novel meta-analytical method may be useful to estimate MCIC for other measures where anchor questions are problematic. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42022323927.

Does patella lowering as part of multilevel surgery improve knee kinematics in children with cerebral palsy and crouch gait? A meta-analysis of comparative studies.

Purpose: To evaluate differences in knee kinematic outcomes of patellar-lowering surgery, specifically patellar tendon advancement or patellar tendon shortening, compared with no-patellar-lowering surgery in multilevel surgery for children with cerebral palsy and crouch gait. Methods: Four databases were searched to retrieve studies published from inception until 2023. Three reviewers independently screened for studies with observational or randomized control designs, comparing two groups of patients with cerebral palsy and crouch gait who underwent multilevel surgery (with patellar-lowering surgery versus no-patellar-lowering surgery), where various gait analysis outcomes were reported (CRD42023450692). The risk of bias was assessed with the Risk Of Bias In Non-randomised Studies - of Interventions (ROBINS-I) tool. Results: Seven studies (249 patients and 368 limbs) met the eligibility criteria. Patients undergoing patellar-lowering surgery demonstrated statistically significant improvements in knee flexion at initial contact (mean difference = -6.39; 95% confidence interval = [-10.4, -2.75]; p = 0.0006; I2 = 84%), minimum knee flexion in stance (mean difference = -14.27; 95% confidence interval = [-18.31, -10.23]; p < 0.00001; I2 = 89%), and clinical knee flexion contracture (mean difference = -5.6; 95% confidence interval = [-9.59, -1.6]; p = 0.006; I2 = 95%), with a significant increase in anterior pelvic tilt (mean difference = 2.97; 95% confidence interval = [0.58, 5.36]; p = 0.01; I2 = 15%). However, improvements in gait deviation index and decrease in peak knee flexion in swing did not reach statistical significance. Subgroup analysis reduced heterogeneity and revealed (1) greater improvement using patellar tendon shortening versus patellar tendon advancement techniques; (2) lack of knee flexion contracture improvement in high-quality or longer-term studies; (3) longer-term improvement only in minimum knee flexion in stance, with a decrease in peak knee flexion in swing; and (4) an inability to assess the potential benefit of rectus femoris procedure and hamstring preservation. Conclusions: Overall, the combination of patellar-lowering surgery with multilevel surgery demonstrated superior improvements in stance-phase knee kinematics compared with multilevel surgery alone, despite an increase in anterior pelvic tilt and a longer-term knee flexion reduction during the swing phase. Level of evidence: Level III, Systematic review of level III studies.

[Reference values for isometric strength tests]. / Orientierungswerte in der isometrischen Kraftdiagnostik.

BACKGROUND: In the environment of orthopaedic rehabilitation, isometric strength testing is part of the monitoring in order to document the success of the therapy. For clinical applications, reference values, or at least orientation benchmarks, are needed for every single device, because of serious concerns for direct inter-device comparisons. According to functional ratios, there is only little literature covering comparability concerns. This study aimed to demonstrate reference values for two strength diagnosis systems for trunk and knee-joint flexion and extension as well as resulting functional ratios along with analyses of reproducibility and vice-versa comparisons. MATERIALS AND METHODS: In a cross-sectional design, reference values (M, SD, Median, IQR, 5 and 95% percentiles) of 98 healthy adults (47 females, age 25.7±8.2 years, BMI 23.3±2.6 kg/m2) were assessed for trunk and knee flexion and extension and the according functional ratios using either the Myoline or the Frei medical system. For a sub-sample of 20 persons (50% females), the mutual explained total variance (r2) and reliability (ICC3.1, SEM, VK%) were analyzed. RESULTS: Both systems were shown to be reliable (ICC3.1 0.76-0.95), while functional ratios demonstrated a lower reliability (ICC3.1 0.62-0.92). For peak forces, the mutual total explained variance (r2) ranged between 19-68%, for functional ratios on an even lower level (5-21%). CONCLUSION: The resulting strength test values, and especially the related functional ratios, obtained with the two strength test devices are not comparable at all, but each device was shown to be a reliable tool. Distributions of body weight adjusted peak forces and functional ratios may serve as device specific benchmark values for strength testing in clinical environments.

Effect of suspensory strategy on balance recovery after lateral perturbation.

Postural stability is essential for performing daily activities and preventing falls, whereby suspensory strategy with knee flexion may play a role in postural control. However, the contribution of the suspensory strategy for postural control during sudden lateral perturbation remains unclear. We aimed to determine how suspensory strategy contributed to postural adjustment during sudden perturbation in the lateral direction and what knee flexion setting maximized its effect. Eighteen healthy young adults (10 male and 8 female) participated in this study. Kinematic data during lateral perturbation at three velocities (7, 15, and 20 cm/s) were collected under three knee flexion angle conditions (0°, 15°, and 65°) using motion capture technology. Postural adjustments to the external perturbation were assessed by four parameters related to the temporal aspects of the center of mass (COM): reaction time, peak displacement/time and reversal time, and minimum value of the margin of stability (minimum-MOS). Our results showed that the COM height before the perturbation significantly lowered with increasing knee flexion angle. The COM reaction times for low and mid perturbation velocities were delayed at 65° of knee flexion compared to 0° and 15°, and the COM reversal times were significantly shorter at 65° of knee flexion than at 0° and 15° across all perturbation velocities. The minimum-MOS at the high-velocity of perturbation was significantly smaller at 65° of knee flexion than at 0° and 15°. In conclusion, the adoption of a suspensory strategy with slight knee flexion induced enhanced stability during sudden external and lateral perturbations. However, excessive knee flexion induced instability.

Knee flexion compensation in postoperative adult spinal deformity patients: implications for sagittal balance and clinical outcomes.

PURPOSE: To determine whether maintaining good sagittal balance with significant knee flexion (KF) constitutes a suboptimal outcome after adult spinal deformity (ASD) correction. METHODS: This single-center, single-surgeon retrospective study, assessed ASD patients who underwent posterior spinal fusion between 2014 and 2020. Inclusion criteria included meeting at least one of the following: PI-LL ≥ 25°, T1PA ≥ 20°, or CrSVA-H ≥ 2 cm. Those with lower-extremity contractures were excluded. Patients were classified into four groups based on their 6-week postoperative cranio-hip balance and KF angle, and followed for at least 2 years: Malaligned with Knee Flexion (MKF+) (CrSVA-H > 20 mm + KFA > 10), Malaligned without Knee Flexion (MKF-) (CrSVA-H > 20 mm + KFA < 10), Aligned without Knee Flexion (AKF-) (CrSVA-H < 20 mm + KFA < 10), and Aligned with Knee Flexion (AKF+) (CrSVA-H < 20 mm + KFA > 10). The primary outcomes of this study included one and two year reoperation rates. Secondy outcomes included clinical and patient reported outcomes. RESULTS: 263 patients (mean age 60.0 ± 0.9 years, 74.5% female, and mean Edmonton Frailty Score 3.3 ± 0.2) were included. 60.8% (160/263 patients) exhibited good sagittal alignment at 6-week postop without KF. Significant differences were observed in 1-year (p = 0.0482) and 2-year reoperation rates (p = 0.0374) across sub-cohorts, with the lowest and highest rates in the AKF- cohort (5%, n = 8) and MKF + cohort (16.7%, n = 4), respectively. Multivariable Cox regression demonstrated the AKF- cohort exhibited significantly better reoperation outcomes compared to other groups: AKF + (HR: 5.24, p = 0.025), MKF + (HR: 31.7, p < 0.0001), and MKF- (HR: 11.8, p < 0.0001). CONCLUSION: Our findings demonstrate that patients relying on knee flexion compensation in the early postoperative period have inferior outcomes compared to those achieving sagittal balance without knee flexion. When compared to malaligned patients, those with CrSVA-H < 20 mm and KFA > 10 degrees experience fewer early reoperations but similar delayed reoperation rates. This insight emphasizes the importance of considering knee compensation perioperatively when managing sagittal imbalance in clinical practice.

Non-surgical correction of knee flexion deformity in persons with haemophilia: A staged multidisciplinary approach.

INTRODUCTION: Flexion deformity of the knee is a common complication following recurrent haemarthrosis in persons with haemophilia (PWH) on episodic factor replacement therapy, restricting independent mobility. There is limited literature on the comprehensive management of this condition. This report provides the outcome of a staged multidisciplinary approach for the correction of knee flexion deformity (KFD) even in limited resource settings. PATIENTS AND METHODS: The data of 49 consecutive PWH who were treated for KFD were analysed. The approach included graded physical therapy (PT), followed by serial casting and/or mobilisation under anaesthesia (MUA). MUA was done in carefully selected knees. Surgical correction was opted when non-surgical methods failed. RESULTS: Of the 49 patients (55 knees), with a median KFD of 40 degrees (range: 10-90), 26/55 (47%) were corrected by graded PT. With serial casting, 9/19 (47%) knees had their KFD corrected. MUA was done for 11 knees of which five achieved correction (45%). Surgical correction was required for only seven knees (12.7%). Following this approach, KFD improved from 40 degrees (range: 10-90) to 15 degrees (range: 0-40), with only minor loss of flexion from 105 (range: 60-155) to 90 degrees (range: 30-150). Out of 55 KFD, 46 (83.6%) KFD were corrected; non-surgical, 39 (70.9%) and surgery, seven (12.7%). The remaining patients (nine KFD; 16.4%) were able to achieve their functional goal despite not meeting the correction criteria. CONCLUSION: This study shows that in PWH, functionally significant KFD correction can be achieved in about 71%, through non-surgical methods, even without prophylactic factor replacement.

Restricted kinematically aligned total knee arthroplasty with an anatomically designed implant can restore constitutional coronal lower limb alignment.

PURPOSE: Restricted kinematically aligned total knee arthroplasty (rKA-TKA) may not restore the constitutional varus alignment in most patients with knee osteoarthritis. This study aimed to investigate (1) the extent to which constitutional lower limb alignment can be restored by rKA-TKA using an anatomically designed implant and (2) which lower limb alignment parameters are associated with patient-reported outcome measures (PROMs). METHODS: This study included 60 patients who underwent rKA-TKA using an anatomically designed implant. Radiographic alignment parameters, including mechanical lateral distal femoral angle (mLDFA), medial proximal tibial angle (MPTA), coronal hip-knee-ankle angle (HKA), coronal joint line obliquity (JLO), posterior tibial slope (PTS), single-leg standing knee flexion angle (KFA), sagittal JLO, and arithmetic HKA (aHKA), were evaluated preoperatively and postoperatively. The Western Ontario and McMaster Universities Arthritis Index (WOMAC) was used for clinical evaluation. RESULTS: The mLDFA, MPTA, and aHKA showed no significant differences before and after surgery. Coronal HKA and PTS have significantly changed from 8.1 ± 8.7° and 9.9 ± 8.6° preoperatively to 3.5 ± 3.1° and 2.5 ± 2.0° postoperatively, respectively (p < 0.001 for each comparison). The postoperative WOMAC total score was significantly correlated with the KFA (r = 0.4063, p = 0.0034) and sagittal JLO (r = -0.3435, p = 0.0157). Postoperative KFA is a causal factor for the increased postoperative WOMAC total score (r = 1.416, 95% confidence interval: 0.491-2.342, p = 0.003). CONCLUSION: rKA-TKA using an anatomically designed implant can restore constitutional coronal lower limb alignment, while postoperative KFA and sagittal JLO were associated with poor PROMs. Care should be taken for the postoperative KFA because it is a risk factor for poor PROMs. LEVEL OF EVIDENCE: Level III, case-control study.

Myoelectric interface for neurorehabilitation conditioning to reduce abnormal leg co-activation after stroke: a pilot study.

BACKGROUND: The ability to walk is an important factor in quality of life after stroke. Co-activation of hip adductors and knee extensors has been shown to correlate with gait impairment. We have shown previously that training with a myoelectric interface for neurorehabilitation (MINT) can reduce abnormal muscle co-activation in the arms of stroke survivors. METHODS: Here, we extend MINT conditioning to stroke survivors with leg impairment. The aim of this pilot study was to assess the safety and feasibility of using MINT to reduce abnormal co-activation between hip adductors and knee extensors and assess any effects on gait. Nine stroke survivors with moderate to severe gait impairment received 6 h of MINT conditioning over six sessions, either in the laboratory or at home. RESULTS: MINT participants completed a mean of 159 repetitions per session without any adverse events. Further, participants learned to isolate their muscles effectively, resulting in a mean reduction of co-activation of 70% compared to baseline. Moreover, gait speed increased by a mean of 0.15 m/s, more than the minimum clinically important difference. Knee flexion angle increased substantially, and hip circumduction decreased. CONCLUSION: MINT conditioning is safe, feasible at home, and enables reduction of co-activation in the leg. Further investigation of MINT's potential to improve leg movement and function after stroke is warranted. Abnormal co-activation of hip adductors and knee extensors may contribute to impaired gait after stroke. Trial registration This study was registered at ClinicalTrials.gov (NCT03401762, Registered 15 January 2018, https://clinicaltrials.gov/study/NCT03401762?tab=history&a=4 ).

The relationship between knee flexion excursion and mechanical stress during gait in medial knee osteoarthritis.

BACKGROUND: A decrease in knee flexion excursion during the loading response may affect not only quadriceps muscle weakness, pain, and inflammatory symptoms, but also lead to physical function decline and activity limitation. The aim of this investigation was to clarify the relationship between knee flexion excursion during the loading response and mechanical stress on the knee joint, muscle strength, pain, and physical function in patients with knee osteoarthritis. METHODS: Twenty patients diagnosed with medial knee osteoarthritis. The participants walked along a 10 m corridor in the laboratory at a comfortable pace. The kinematic and kinetic data were collected using a 3D motion analysis system. We employed to control for gait speed and age while examining the relationship between knee flexion excursion during the loading response and mechanical stress on the knee joint, muscle strength, pain, and physical function. FINDINGS: Knee flexion excursion showed a significant positive correlation with the peak and angular impulse of knee flexion moment. In the partial correlation coefficients controlling for age and gait speed, significant negative correlations were found between knee flexion excursion and knee adduction moment angular impulse. INTERPRETATION: It can be inferred that gait with reduced knee flexion movement during the loading response in patients with knee osteoarthritis may result in increased mechanical stress on the knee joint in the frontal plane. Exercise interventions aimed at increasing knee flexion excursion may result in a reduction in disease progression.

Associations between femoral 3D curvature and sagittal imbalance of spine.

Background: The sagittal imbalance (SI) of spine triggers compensatory mechanisms (CMs) of lower extremity (LE) to restore trunk balance. These CMs can cause long-period stress on the femur and may possibly alter the femoral morphology. This cross-sectional observational study aimed to answer the following questions: (a) Do SI subjects exhibit greater femoral bowing compared to subjects with sagittal balance? (b) Are there associations between femoral bowing and CMs of LE in SI subjects? Methods: Subjects who underwent biplanar full body radiographs with the EOS imaging system between January 2016 and September 2021 were recruited. Sagittal parameters included T1-pelvic angle (TPA), pelvic incidence (PI), pelvic tilt (PT), sacral slope, lumbar lordosis (LL), PI-LL, and PT/PI ratio. LE parameters were femoral obliquity angle (FOA), knee flexion angle (KA), and ankle dorsiflexion angle. Femoral bowing was quantified as 3D radius of femoral curvature (RFC). Associations between 3D RFC and the radiographic parameters were analyzed. Results: A total of 105 subjects were included, classified into balance group (TPA < 14°, n = 40), SI group (TPA ≥ 14° and KA <5°, n = 30), and SI with knee flexion group (TPA ≥ 14° and KA ≥ 5°, n = 35). 3D RFC was significantly lower in SI with knee flexion group compared to the other two groups (both p < 0.001). Stepwise linear regression showed that age, SI and knee flexion, femoral length (FL), FOA, and KA were independent predictors for 3D RFC. Conclusion: Greater femoral bowing is observed in subjects with SI and knee flexion compared to the balanced population. CM parameters, including KA and FOA, are associated with 3D RFC. Further longitudinal study is needed to investigate the cause-and-effect relationship between SI, CMs of LE, and femoral bowing.