Search Results (25)

This study evaluated the test–retest reliability, standard error of measurement (SEM), and minimal detectable change (MDC) of frontal plane projection angles (FPPAs) across five single-leg tasks in individuals with patellofemoral pain (PFP). Two-dimensional video data was collected from ten individuals with predominantly unilateral PFP. Participants performed single-leg squat, single-leg landing, single-leg hop, forward step-down, and lateral step-down across two testing sessions. FPPAs were measured at peak knee flexion for each task, including trunk lean angle, knee FPPA, hip FPPA, and dynamic valgus index. Test–retest reliability was assessed using intraclass correlation coefficients (ICCs). Our findings indicate that test–retest reliability and measurement error for trunk and lower limb FPPA varied across tasks in individuals with PFP. The lowest ICC was observed for hip FPPA, particularly during single-leg squat and lateral step-down tasks. Among the five tasks tested, the single-leg squat appeared to be the most demanding task, demonstrating the lowest ICCs, and highest SEM and MDC values across all four outcome measures (trunk lean angle, knee and hip FPPAs, and dynamic valgus index). The dynamic valgus index consistently showed larger SEM and MDC values than isolated hip or knee FPPAs, likely reflecting compounded measurement errors across segments. These findings provide preliminary insights, though confirmation in larger samples in persons with PFP is warranted. Full article

Tibial torsion significantly influences knee biomechanics, yet its interaction with ACL reconstruction history in elite alpine skiers remains under-investigated. In this cross-sectional observational study, we analyzed 20 elite alpine skiers (7 ACL-reconstructed, 13 non-injured) using a markerless motion capture system during dynamic tasks (Squat, Single-Leg Squat, Lunge). Static tibial torsion was assessed via the Transmalleolar Axis and Thigh–Foot Angle. The results revealed a critical divergence in biomechanical strategies based on tibial alignment (p < 0.05). Skiers with rotational deformity adopted a pattern we describe as a “Stiffness Strategy”, characterized by suppressed knee valgus and hip rotation, but relied on excessive ankle dorsiflexion (39.5°)—a compensatory mechanism that may become limited when constrained by rigid ski boots. In contrast, ACL-reconstructed skiers with normal alignment exhibited what we term an “Instability Strategy”, showing dynamic valgus collapse and persistent asymmetry. These findings suggest that “one-size-fits-all” rehabilitation may be insufficient. We propose that injury prevention protocols may benefit from incorporating anatomical screening, focusing on decoupling mobility for skiers with tibial torsion and enhancing dynamic stability for those with normal alignment. Full article

Background/Objectives: Hallux valgus (HV), a common foot deformity, is difficult to quantify beyond traditional angular measurements. This study introduces a novel dynamic distance mapping technique to visualize HV progression and identify spatial features linked to severity. Methods: A retrospective analysis of 335 feet from 178 patients undergoing HV surgery at Hasharon Hospital, Israel (2014–2024), utilized custom Python software to annotate 24 landmarks on preoperative standing anteroposterior radiographs. This generated 276 normalized Euclidean distances, analyzed via Pearson correlation against HV angles (HVA, IMA, DMAA, HIA). Results: Seven distances correlated negatively (r > 0.4, p < 0.05) and seven positively with HVA, involving the distal phalanx, sesamoids, and second metatarsal. Eleven distances showed strong positive correlation (r > 0.4, p < 0.05) with IMA, reflecting displacement patterns. Moderate correlations were observed with DMAA (six negative, r −0.3 to −0.4; two positive, r 0.3 to 0.4, p < 0.05) and HIA (two negative, r −0.3 to −0.4, p < 0.05). Visualizations highlighted progressive spatial changes. Conclusions: Dynamic distance mapping provides valuable insights into hallux valgus (HV) progression, as evidenced by significant correlations with HVA and IMA, supporting its potential role in surgical planning. However, its ability to capture 3D deformities requires validation against weightbearing computed tomography (WBCT). Future research should explore correlations with specific indications for corrective osteotomies to enhance clinical applicability. Full article

Background: Anterior cruciate ligament (ACL) rupture is one of the most common injuries in playing rugby. The aim of this study was to assess the effect of a custom-designed training program on changes in dynamic knee valgus angle (DKV) and Reactive Strength Index (RSI), which are the main risk factors, in a group of female Rugby-7 players. Methods: A total of 16 professional Rugby-7 players completed an 8-week KAT program intervention, which was incorporated twice a week throughout this time. In both the pre- and post-tests, dynamic knee valgus was assessed during the drop jump (DJ) test using the frontal plane projection angle (FPPA) method. The jumps were analyzed using Dartfish 2024 software. Results: The post-tests revealed an increase in RSI values (p = 0.0496; SD = 1.25 ± 0.44 vs. 1.40 ± 0.35) and a reduction in valgus of the left knee joint (p = 0.01; SD = 9.08 ± 11.86 vs.0.00 ± 7.42). The correlation between RSI and the valgus angle produced inconclusive results (rs = −0.69; p < 0.01; rs = −0.35; p = 0.25; rs = −0.38; p = 0.2; rs = −0.2; p = 0.51). Cohen’s d = −0.37964. Conclusions: The training program proved effective in improving RSI scores and reducing the valgus angle of the left lower limb, which functioned as the supporting leg. These findings potential KAT implementation as a warm-up routine in professional women’s rugby clubs. Full article

Dynamic knee valgus is a biomechanical condition often linked to an increased risk of knee injuries, particularly in female athletes, due to greater hip adduction, internal rotation, and knee abduction during dynamic movements. This study aimed to assess the impact of neuromuscular fatigue on dynamic knee valgus in female basketball players during single-leg drop jumps (DJ-SL) and change of direction (COD) tests at 45° and 90°. Thirty-three athletes, divided into national and regional performance groups, performed these movements before and after a fatigue protocol. Fatigue was induced through a series of anaerobic exercises, and frontal plane projection angle (FPPA) was used to measure knee valgus. The results showed that dynamic knee valgus increased with the angle of directional change (from 24.77° ± 8.25 at 45° to 34.55° ± 10.40 at 95° pre-fatigue, and from 26.59° ± 12.30 at 45° to 35.87° ± 10.37 post-fatigue), but was not significantly affected by neuromuscular fatigue. The national group demonstrated lower valgus angles compared to the regional group, indicating potential performance differences based on competitive level. These findings suggest that while neuromuscular fatigue does not notably impact knee valgus, the higher valgus angles during directional changes warrant attention in injury prevention programs for female basketball players. Further research is needed to explore other factors influencing knee mechanics and injury risk. Full article

(1) Background: Dynamic knee valgus (DKV) is a common biomechanical risk factor for knee injuries, particularly in sports involving high-intensity movements, such as basketball. While neuromuscular control and structural alignment contribute to DKV, recent evidence indicates that lower limb muscle power (LLMP) and cardiorespiratory fitness (CRF) may significantly influence DKV. This study aims to examine the relationship among LLMP, CRF, and DKV in adolescent basketball athletes. (2) Methods: A total of 104 adolescent basketball athletes (63.5% boys), 12 to 17 years old (13.87 ± 1.46 years) participated in this study. Anthropometric and demographic characteristics such as sex, age, height, weight, and body mass index (BMI) were recorded. The Counter Movement Jump (CMJ) was used for the evaluation and prediction of the LLMP, the 20 m shuttle run test (20mSRT) was used for the evaluation and prediction of CRF, and the single-leg drop jump (SLDJ) was used for the evaluation of DKV via a two-dimensional (2D) kinematic analysis. Statistical analysis included Pearson and Spearman correlations, as well as multiple linear regression, to determine the relationship among LLMP, CRF, and DKV. (3) Results: A statistical analysis revealed strong correlations among LLMP, CRF, and DKV. Pearson’s correlation coefficients demonstrated significant associations between the VO₂max and frontal plane projection angle (FPPA) (r = 0.78, p < 0.001), as well as between LLMP and FPPA (r = 0.82, p < 0.001). Multiple linear regression analysis showed that VO₂max and LLMP together accounted for 85% of the variance in FPPA (R² = 0.85, p < 0.001). (4) Conclusions: The findings highlight that both aerobic capacity and lower limb muscle power significantly contribute to knee valgus control among adolescent basketball players. Implementing training programs focused on improving lower limb muscle power and cardiorespiratory fitness may enhance knee stability and reduce the risk of lower limb injuries. Given the strong predictive value of VO₂max and LLMP for knee control, targeted training programs focusing on neuromuscular conditioning and aerobic capacity may be effective for injury prevention. Full article

Background/Objectives: Hindfoot valgus malalignment, characterized by the lateral deviation of the calcaneus and medial tilting of the talus, disrupts hindfoot biomechanics and increases strain on subtalar joint. This study evaluates weightbearing and non-weightbearing imaging modalities to identify dynamic alignment changes and their diagnostic implications. This study aims to (1) quantify changes in subtalar joint parameters between non-weightbearing computed tomography (NWBCT) and weightbearing computed tomography (WBCT) in patients with hindfoot valgus; (2) evaluate correlations between WBCT and standard radiographic parameters; and (3) identify radiographic predictors of subtalar joint status during weightbearing. Methods: We reviewed 70 patients with confirmed hindfoot valgus malalignment (hindfoot valgus angle >5°), identified through radiographic measurements. Of these, 32 underwent both NWBCT and WBCT, while 38 underwent WBCT alone. Hindfoot alignment angle (HAA) and hindfoot alignment ratio (HAR) were measured on hindfoot alignment radiographs, while heel valgus angle (HVA), talocalcaneal distance (TCD), subtalar joint subluxation (SL) and calcaneofibular distance (CF) were assessed on CT. Results: WBCT revealed significant increases in HVA and SL (both, p < 0.001) and decreases in TCD and CF (p < 0.001 and p = 0.002, respectively) compared to NWBCT, reflecting dynamic subtalar joint changes under weightbearing conditions. Receiver operating characteristic (ROC) analysis identified hindfoot alignment angle (HAA) as the most reliable predictor of talocalcaneal osseous contact, with a cutoff value of >9.25° based on Youden’s index, yielding a sensitivity of 73% and specificity of 81.8%. Inter- and intra-observer reliabilities for all parameters were excellent (ICC > 0.81). Conclusions: WBCT provides critical insights into subtalar joint dynamics under physiological loads, surpassing NWBCT in assessing weightbearing-induced alignment changes. Although standard radiographic parameters, particularly HAA, can serve as reliable, cost-effective predictors of subtalar joint pathology in resource-limited settings, WBCT should still be preferred when available, especially in patients with significant malalignment or when detailed dynamic evaluation is needed to guide clinical decision-making. Full article

Background/Objectives: Patellofemoral pain (PFP) is believed to be a precursor to knee osteoarthritis (OA). The primary purpose of this study was to compare matrix metalloproteinase-9 (MMP-9) levels in young adult females with and without PFP. The secondary purpose was to determine the associations between MMP-9, patella position, hip and knee kinematics, and pain in females with PFP. Methods: Plasma was analyzed for MMP-9. Patellar position was measured using diagnostic ultrasound as the degree of offset (RAB angle) from the deepest aspect of the femoral trochlear groove to the inferior pole of the patella. A positive RAB angle suggested patella lateralization. Hip and knee kinematics during a single-leg squat were measured using 2-dimensional motion analysis and quantified as the dynamic valgus index (DVI), a combined measure of hip and knee motion. A higher DVI suggests increased valgus loading at the patellofemoral joint. Pain was measured using a 10 cm visual analog scale. Results: Females with PFP had significantly higher levels of MMP-9 than controls (72.7 vs. 58.0 ng/mL, p = 0.03). Females with PFP had a significant positive association between MMP-9 and patella lateralization (r = 0.38, p = 0.04), suggesting that greater patellar lateralization may contribute to increased joint inflammation. A significant inverse association was observed between MMP-9 and the DVI (r = −0.50, p = 0.007), indicating that individuals with higher inflammatory marker levels may adopt movement patterns that reduce valgus loading. Conclusions: The significant association between MMP-9 and patella lateralization suggested a potential link between patella alignment and joint inflammation, which may contribute to early joint degeneration. The inverse association between MMP-9 levels and the DVI suggested that subjects with higher MMP-9 levels adjusted their movement pattern as a compensatory mechanism to reduce knee valgus stress to reduce joint degeneration. Full article

Subtrochanteric nonunion is especially challenging. Extramedullary fixation using fixed-angle devices with a closing lateral wedge osteotomy is the standard surgical procedure for restoring the hip’s normal alignment and achieving bone union. However, this procedure is technically demanding and relies on devices that facilitate bone union in a non-dynamic manner, along with the limitations that this type of fixation entails, especially in this highly biomechanically stressed area. This paper aims to describe a novel surgical technique to heal subtrochanteric nonunion based on dynamic fixation performed through an over-valgus correction of the hip and fixed with a dynamic hip screw (DHS). Between March 2022 and July 2023, five patients diagnosed with nonunion of a subtrochanteric fracture were operated on by a single surgeon and followed prospectively. The average age of the patients was 64 (range: 34–85). The mean duration of surgery was 112 min (range: 63–153). The femoral neck angle before surgery was 120° (range: 110°–122°) and 147° (range: 142°–150°) after surgery. The mean leg length increased by 8 mm (range: 6–12). The Harris hip score improved from 38 points (range: 30–44) to 90 points (range: 88–96), corresponding to excellent or good results. All patients healed without major complications and were asymptomatic after 12 months of follow-up. In conclusion, over-valgus correction using a DHS is a novel technique that seems helpful for subtrochanteric nonunion. It allows for dynamic fixation, offering the advantages of dynamic fixation, especially in this high-stress area. It is also performed without osteotomy, making it a less demanding technique than the current methods described. Full article

Background: Improper neuromuscular control with excessive dynamic valgus loading of the knee has been identified as one of the main anterior cruciate ligament injury risk factors. This study aimed to analyze the impact of the FIFA 11+ training program on the valgus loading of the knee in academy soccer players over a competitive season. Methods: A prospective study was conducted on 85 players. The drop vertical jump test was carried out before the match and at the end of the same match at the beginning and at the end of the season over a period of 11 months. Results: An increase of the varus angle on the right limb was noted between the start and the end of the season at the beginning of the match (−4.7 ± 8.9 versus −6.9 ± 6, p = 0.003) and between the start and the end of the match in values measured at the beginning of the season (−4.7 ± 8.9 versus −7.7 ± 9, p < 0.001). An increase of the flexion angle of both limbs was noted between the start and the end of the season in values measured at the start of the match (left limb 76.8 ± 32.8 versus 98.6 ± 17.2, p < 0.001; right limb 76.4 ± 32.8 versus 96.1 ± 16.1, p < 0.001) and between the start and the end of the season in values measured at the end of the match (left limb 92.8 ± 19.1 versus 98.5 ± 16.3, p = 0.002; right limb 92.6 ± 19.2 versus 96.7 ± 14.5, p = 0.013). Conclusions: A decrease in dynamic valgus angle and an increase in knee flexion angle measured with the DVJ test were noted between the start and the end of the season, suggesting a protective role of the FIFA 11+ training program. Full article

Background: Patellofemoral pain is one of the most common injuries in recreational runners, with significant implications for dynamic knee valgus. The knee valgus angle can be corrected surgically or with a more conservative non-operative approach. Increasing running cadence may be an effective biomechanical gait retraining intervention to reduce knee valgus and thus patellofemoral pain. The primary purpose of this study was to examine if an increase in cadence could change the knee valgus angle. Methods: Ten asymptomatic recreational runners were recorded running on a treadmill during control and experimental intervals. Each interval lasted five minutes, and participants ran at 100% and 110% of their baseline cadence. Peak angles of knee valgus were compared between both intervals using the video analysis software application Dartfish Express. A paired sample, a two-tailed t-test, was used to determine the significant difference between bilateral frontal plane knee angle measurements during both intervals. Results: The average decrease in knee valgus measured in control versus experimental intervals was 2.23° for the right leg and 2.05° for the left leg, with a significance of p < 0.001 and p < 0.001, respectively. Conclusion: The results indicated a statistically significant decrease in angles of dynamic knee valgus, attributable to increased cadence. These changes in knee valgus angle are likely to have a positive impact on preventing and reducing pain associated with PFP. Full article

Anterior cruciate ligament (ACL) injuries are a common issue in basketball. Several studies point to subtalar pronation as a relevant risk factor for these injuries, despite their multiarticular and multiplanar nature. This study evaluated the correlation between subtalar pronation and ACL injuries in female basketball players. A total of 30 players were recruited and divided into two groups: 15 with previous ACL injury and 15 without injury. The navicular drop test (NDT) and drop vertical jump test were applied to quantify parameters such as navicular drop, calcaneal eversion, ankle dorsiflexion, knee flexion, and dynamic valgus. The results showed significantly higher NDT values (6.93 ± 1.64 mm vs. 5.41 ± 1.96 mm, p = 0.029) and maximum calcaneal eversion angle (10.94 ± 3.22° vs. 5.30 ± 3.33°, p < 0.001) in the injured group. There were also significant differences in maximum dynamic valgus (152.73 ± 15.00° vs. 165.26 ± 5.628°, p = 0.005) and knee flexion (93.70 ± 7.47° vs. 82.92 ± 11.14°, p = 0.004) between groups. These findings suggest that subtalar pronation, assessed by NDT, and calcaneal eversion could be indicators of higher susceptibility to ACL injuries in female basketball players. Full article

Both weak muscle strength and impaired neuromuscular control has previous been suggested as risk factors for future traumatic knee injury. However, data on the relationship between these two factors are scarce. Thus, the aim of this study was to investigate the relationship and influence of the one repetition maximum (1RM) barbell squat strength on dynamic knee valgus in elite female and male handball players. In this cross-sectional study 22 elite handball players (7 females) were included. A unilateral drop jump (VDJ) test was used for the assessment of frontal plane dynamic knee valgus. Players also performed a one repetition maximum (1RM) barbell squat test, expressed relative to bodyweight (r1RM), to assess maximal strength, which were dichotomized to analyze ‘weak’ versus ‘strong’ players according to median. Correlations were noted between r1RM in squat and knee valgus angle for both the non-dominant (r = −0.54; p = 0.009) and dominant leg (r = −0.46, p = 0.03). The odds of knee valgus were eight times higher, for the dominant leg, in the weak group compared to the strong group (p = 0.03) and 27 times higher, for the non-dominant leg (p = 0.002). The outcome of the present study suggests that maximum squat strength plays an important role when it comes to neuromuscular control of the knee, and that weak handball players are at higher risk of knee valgus compared to strong players during jumping activity. Full article

Dynamic knee valgus (DKV) is a frontal plane knee kinematic alteration that has been associated with patellofemoral pain (PFP) in female runners. DKV is commonly assessed in clinical practice by measuring frontal plane knee projection angle (FPPA) during squat tests. However, it remains unclear whether the DKV observed in these tests is similar to or correlates with that observed during running in female runners. The aims of this cross-sectional study were to correlate and compare DKV, by measuring FPPA values, in a lateral step-down (LSD) squat test and running in female runners with and without PFP. A two-dimensional (2D) video analysis of the LSD test and running was carried out for 21 asymptomatic female runners and 17 PFP female runners in order to determine FPPA values. A Pearson correlation test and a factorial ANOVA with Bonferroni post hoc correction were used for statistical analysis. The FPPAs recorded in the LSD test were significantly higher than those recorded during running in the asymptomatic (16.32° ± 5.38 vs. 4.02° ± 3.26, p < 0.01) and PFP groups (17.54° ± 7.25 vs. 4.64° ± 3.62, p < 0.01). No significant differences were found in FPPA values between asymptomatic and PFP runners during the LSD test (16.32° ± 5.38 vs. 17.54° ± 7.25, p = 0.55) and running (4.02° ± 3.26 vs. 4.64° ± 3.62, p = 0.58). There was a small (r < 0.3) and non-significant (p > 0.05) correlation in FPPAs between the LSD test and running in both groups. According to our results, DKV was not similar during the LSD test and running, and there was no significant correlation in FPPA values between the LSD test and running in both groups. Therefore, clinicians and therapists should be aware of these findings when using the LSD test in clinical practice to evaluate DKV in female runners with or without PFP. Full article

Background: Anterior cruciate ligament (ACL) injuries have been studied using a variety of methods and tools. However, each is hindered by specific limitations with respect to its application. Aim: To assess the combined effects of external moments and muscle activations on ACL loading using serial, forward dynamics (FD) simulations of single leg, hyperextension landings in OpenSim. Methods: The FD tool of OpenSim was iteratively run using different combinations of knee-spanning muscle activation levels, internal rotation and valgus knee moment magnitudes. A regression was conducted on the data in order to predict ACL loading under different conditions. Results: A purely abduction moment leads to greater mean ACL loading than a purely internal rotation moment or any combination of the two. Additionally, the generalized boosted regression model using both external moments and certain knee muscles identified the internal rotation moment as the most important variable in predicting the ACL load (R² = 0.9; p < 0.0001). Conclusion: This study demonstrated a novel and practical application of an OpenSim musculoskeletal model that supports the ACL injury mechanism of landing with low knee flexion angles, high muscle forces of the Quadriceps muscles and an external knee valgus moment, though further investigation is needed. Full article