3D Knee Research Articles

Large correction in opening wedge high tibial osteotomy with resultant joint-line obliquity induces excessive shear stress on the articular cartilage.

The purpose of this study was to analyse the resultant stress induced by joint-line obliquity after HTO for varus knee deformity using a three-dimensional (3D) finite element model analysis. The geometrical bone data used in this study were derived from commercially available human bone digital anatomy media. The 3D knee models were developed using 3D computer-aided design software. The articular surface was overlaid with a 2-mm-thick cartilage layer for both femoral and tibial condyles. Ligament structures were simulated based on properties reported in previous anatomical studies. Regarding the loading condition, isolated axial loads of 1200N with lateral joint-line inclinations of 2.5°, 5°, 7.5°, and 10° in reference to the horizontal axis were applied to the femur to simulate the mechanical environment in a knee with joint-line obliquity. A steep rise of shear stress in the medial compartment was noted in the model with obliquity of 5° or more. This laterally directed shear stress exhibited an incremental increase in accordance with the obliquity angle. The maximum shear stress value in the medial cartilage increased from 1.6MPa for the normal knee to 3.3, 5.2, and 7.2MPa in the joint-line obliquity models with 5°, 7.5°, and 10° of obliquity, respectively. The effects of HTO for varus knee deformity on the amount/distribution of stresses in the articular cartilage were analysed using a 3D finite element model. It was shown that joint-line obliquity of more than 5° induced excessive shear stress in the tibial articular cartilage. A large amount of correction in OWHTO with a resultant joint-line obliquity of 5° or more may induce detrimental stress to the articular cartilage. Double-level osteotomy should be considered as a surgical option in this situation.

Transfer of improved movement technique after receiving verbal external focus and video instruction

PurposeIt is unknown how movement patterns that are learned carry over to the field. The objective was to determine whether training during a jump-landing task would transfer to lower extremity kinematics and kinetics during sidestep cutting.MethodsForty healthy athletes were assigned to the verbal internal focus (IF, n = 10), verbal external focus (EF, n = 10), video (VI, n = 10) or control (CTRL, n = 10) group. A jump-landing task was performed as baseline followed by training blocks (TR1 and TR2) and a post-test. Group-specific instructions were given in TR1 and TR2. In addition, participants in the IF, EF and VI groups were free to ask for feedback after every jump during TR1 and TR2. Retention was tested after 1 week. Transfer of learned skill was determined by having participants perform a 45° unanticipated sidestep cutting task. 3D hip, knee and ankle kinematics and kinetics were the main outcome measures.ResultsDuring sidestep cutting, the VI group showed greater hip flexion ROM compared to the EF and IF groups (p < 0.001). The EF (p < 0.036) and VI (p < 0.004) groups had greater knee flexion ROM compared to the IF group.ConclusionsImproved jump-landing technique carried over to sidestep cutting when stimulating an external attentional focus combined with self-controlled feedback. Transfer to more sport-specific skills may demonstrate potential to reduce injuries on the field. Clinicians and practitioners are encouraged to apply instructions that stimulate an external focus of attention, of which visual instructions seem to be very powerful.Level of evidenceII.

Three-dimensional knee kinematic analysis during treadmill gait: Slow imposed speed versus normal self-selected speed.

ObjectivesWhilst gait speed is variable between healthy and injured adults, the extent to which speed alone alters the 3D in vivo knee kinematics has not been fully described. The purpose of this prospective study was to understand better the spatiotemporal and 3D knee kinematic changes induced by slow compared with normal self-selected walking speeds within young healthy adults.MethodsA total of 26 men and 25 women (18 to 35 years old) participated in this study. Participants walked on a treadmill with the KneeKG system at a slow imposed speed (2 km/hr) for three trials, then at a self-selected comfortable walking speed for another three trials. Paired t-tests, Wilcoxon signed-rank tests, Mann-Whitney U tests and Spearman’s rank correlation coefficients were conducted using Stata/IC 14 to compare kinematics of slow versus self-selected walking speed.ResultsBoth cadence and step length were reduced during slow gait compared with normal gait. Slow walking reduced flexion during standing (10.6° compared with 13.7°; p < 0.0001), and flexion range of movement (ROM) (53.1° compared with 57.3°; p < 0.0001). Slow walking also induced less adduction ROM (8.3° compared with 10.0°; p < 0.0001), rotation ROM (11.4° compared with 13.6°; p < 0.0001), and anteroposterior translation ROM (8.5 mm compared with 10.1 mm; p < 0.0001).ConclusionThe reduced spatiotemporal measures, reduced flexion during stance, and knee ROM in all planes induced by slow walking demonstrate a stiff knee gait, similar to that previously demonstrated in osteoarthritis. Further research is required to determine if these characteristics induced in healthy knees by slow walking provide a valid model of osteoarthritic gait.Cite this article: N. Mannering, T. Young, T. Spelman, P. F. Choong. Three-dimensional knee kinematic analysis during treadmill gait: Slow imposed speed versus normal self-selected speed. Bone Joint Res 2017;6:514–521. DOI: 10.1302/2046-3758.68.BJR-2016-0296.R1.

Short-term Impact of Anterior Cruciate Ligament Reconstruction in an Adolescent Population on 3D Knee Kinematics

Objectives:Gait analysis is a proven method for assessing knee biomechanical adaptations in anterior cruciate ligament deficient (ACLD) patients and to quantify the impact of the reconstructive surgery (ACLR). In an adult population, ACLR has shown partial kinematic correction, as they remain in internal tibial rotation, putting them at risk of rotational instability and develop osteoartitis. ACLD adolescents likely adopt similar gait changes to reduce knee instability, but may show quicker or more return to the normal compared to adults. The purpose of this study is to compare the tridimensional (3D) knee kinematics before and after ACLR in adolescents.Methods:25 ACLD patients aged between 13 and 19 years old on a waiting list for ACLR were recruited. Bilateral knee 3D kinematic data was gathered during treadmill walking at comfortable self-selected speed using the KneeKGTM System before and 6-9 months after ACLR. Each participant underwent the same surgical protocol (2-strand hamstring tendon graft, hamstring harvest proximally and kept distally, transphyseal tibial tunnel and transepiphyseal femoral tunnel) by the same experienced surgeon. Three analyses were done: ACLD knee pre vs. post-surgery, contralateral healthy knee pre vs. post-surgery, and ACLR knee vs. healthy contralateral knee.Results:In the sagittal and transverse planes, kinematic patterns remained similar to the pre-op; maintaining the characteristic knee flexion gait pattern during single support phase which is well documented in adult ACLD (hamstring facilitation strategy). The ACLR knee exhibited a more valgus dynamic alignment compared to pre-surgery throughout the gait cycle. The healthy contralateral knee kinematics displayed no significant changes in the frontal and sagittal planes after surgery compared to the pre-op pattern. In the transverse plane, post-op gait analysis showed significantly more external rotation at heel-strike and through weight acceptance. While looking at the gait symmetry post-surgery, ACLR knee revealed significantly more valgus while remaining in greater flexion during single limb support. In the transverse plane, an external rotation tendency is observed in the ACLR knee throughout the gait cycle, except during weight acceptance.Conclusion:This study shows that kinematic adaptations found in ACLD adolescents are likely to endure short term after surgery. For example, the greater knee flexion gait pattern used before surgery is still used after ACLR. Interestingly, adolescents used an external tibial rotation adaptation to limit internal tibial instability before the surgery and this pattern was still present post-surgery. Even if theses protection strategies are efficient, the increased dynamical valgus movement seen could place the graft under pressure while increasing patellofemoral stresses, a common complaint after ACLR. Lastly, post-surgery, the contralateral knee seems to mimic the external tibial rotation gait pattern strategy seen in ACL-knee. This study demonstrates that gait protective strategies are still present short term after the surgery. Biomechanical assessment helps ID these adaptations to optimize post-op rehabilitation and prevent secondary injuries.

Biomechanics of Knee Joints after Anterior Cruciate Ligament Reconstruction.

This study aimed to investigate the biomechanical properties of anterior cruciate ligament (ACL); tibial, femoral articular cartilage; and meniscus in knee joints receiving computer-aided or conventional ACL reconstruction. Three-dimensional (3D) knee joint finite element models were established for healthy volunteers (normal group) and patients receiving computer-aided surgery (CAS) or conventional (traditional surgery [TS]) ACL reconstruction. The stress and stress distribution on the ACL, tibial, femoral articular cartilage, and meniscus were examined after force was applied on the 3D knee joint finite element models. No significant differences were observed in the stress on ACL among normal group, CAS group, and TS group when a femoral backward force was loaded. However, when a vertical force of 350 N was loaded on the knee joints, TS group had significant higher stress on the articular cartilage and meniscus than the other two groups at any flexion angle of 0, 30, 60, and 90 degrees. However, no significant differences were observed between CAS group and normal group. In conclusion, computer-aided ACL reconstruction has advantages over conventional surgery approach in restoring the biomechanical properties of knee joints, thus reducing the risk of damage to the knee joint cartilage and meniscus after ACL reconstruction.

3D Hip And Knee Mechanics During Hop Tests After ACL Reconstruction Measured With Inertial Sensors

Hop testing after an Anterior Cruciate Ligament reconstruction (ACLR) is a common functional test to determine return to play status. Due to the difficulty in capturing knee and hip mechanics over a large area while hopping little is known of differences in kinematics that may persist. Advancements

3D Knee Bone Shape Predisposes to ACL Rupture: Data from the Osteoarthritis Initiative and the Kanon Study

3D Knee Bone Shape Predisposes to ACL Rupture: Data from the Osteoarthritis Initiative and the Kanon Study

Multiobjective optimization of cartilage stress for non-invasive, patient-specific recommendations of high tibial osteotomy correction angle – a novel method to investigate alignment correction

Medial opening wedge high tibial osteotomy (MOWHTO) is a surgical procedure to treat knee osteoarthritis associated with varus deformity. However, the ideal final alignment of the Hip-Knee-Ankle (HKA) angle in the frontal plane, that maximizes procedural success and post-operative knee function, remains controversial. Therefore, the purpose of this study was to introduce a subject-specific modeling procedure in determining the biomechanical effects of MOWHTO alignment on tibiofemoral cartilage stress distribution. A 3D finite element knee model derived from magnetic resonance imaging of a healthy participant was manipulated in-silico to simulate a range of final HKA angles (i.e. 0.2°, 2.7°, 3.9° and 6.6° valgus). Loading and boundary conditions were assigned based on subject-specific kinematic and kinetic data from gait analysis. Multiobjective optimization was used to identify the final alignment that balanced compressive and shear forces between medial and lateral knee compartments. Peak stresses decreased in the medial and increased in the lateral compartment as the HKA was shifted into valgus, with balanced loading occurring at angles of 4.3° and 2.9° valgus for the femoral and tibial cartilage respectively. The concept introduced here provides a platform for non-invasive, patient-specific preoperative planning of the osteotomy for medial compartment knee osteoarthritis.

Mechanical biomarkers of medial compartment knee osteoarthritis diagnosis and severity grading: Discovery phase

ObjectiveTo investigate, as a discovery phase, if 3D knee kinematics assessment parameters can serve as mechanical biomarkers, more specifically as diagnostic biomarker and burden of disease biomarkers, as defined in the Burden of Disease, Investigative, Prognostic, Efficacy of Intervention and Diagnostic classification scheme for osteoarthritis (OA) (Altman et al., 1986). These biomarkers consist of a set of biomechanical parameters discerned from 3D knee kinematic patterns, namely, flexion/extension, abduction/adduction, and tibial internal/external rotation measurements, during gait recording. Methods100 medial compartment knee OA patients and 40 asymptomatic control subjects participated in this study. OA patients were categorized according to disease severity, by the Kellgren and Lawrence grading system. The proposed biomarkers were identified by incremental parameter selection in a regression tree of cross-sectional data. Biomarker effectiveness was evaluated by receiver operating characteristic curve analysis, namely, the area under the curve (AUC), sensitivity and specificity. ResultsDiagnostic biomarkers were defined by a set of 3 abduction/adduction kinematics parameters. The performance of these biomarkers reached 85% for the AUC, 80% for sensitivity and 90% for specificity; the likelihood ratio was 8%. Burden of disease biomarkers were defined by a 3-decision tree, with sets of kinematics parameters selected from all 3 movement planes. ConclusionThe results demonstrate, as part of a discovery phase, that sets of 3D knee kinematic parameters have the potential to serve as diagnostic and burden of disease biomarkers of medial compartment knee OA.

3D knee kinematics variability pre-operation versus post-operation in adolescence with Anterior Cruciate Ligament injury using functional principle component analysis

&lt;p&gt;&lt;strong&gt;Background: &lt;/strong&gt;Anterior cruciate ligament (ACL) injuries in adolescents have increased in the past decade. The goal of ACL reconstructive surgery is to restore knee stability, however apart from subjective manual testing, there is no objective method to assess the impact of the treatment on knee stability. In clinical biomechanics, decreased variability in three dimensional (3D) kinematic angles can be associated with increased stability of the joint in performing a movement. Typically, the study of variability of 3D knee kinematics proceeds by reducing what are intrinsically functional responses to a single discrete measurement (e.g. peak flexion angle). As a result, many potentially informative data is ignored.&lt;strong&gt;&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Aim&lt;/strong&gt;: Prospective gait variability analysis pre- and 6 months post- ACL reconstructive surgery in adolescence patients using Principle Component Analysis (FPCA). &lt;/p&gt;&lt;p&gt;&lt;strong&gt;Method: &lt;/strong&gt;FPCA is a multivariate statistical data analysis technique that focuses on treating an entire dataset as functions.&lt;strong&gt; &lt;/strong&gt;Twenty eight ACL adolescent patients pre- and post-operation walked on a treadmill and the 3D knee kinematics were collected (flexion/extension, abduction/adduction and internal/external rotation angles). Functional Principle Component (FPCs) scores of the angle data were extracted to compare variability in gait. Repeated measures of ANOVA and box plots on FPC scores provided evidence of significant difference with decreased variability post-operation for both within-group and within-patients studies.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Conclusion&lt;/strong&gt;:&lt;/p&gt;&lt;p&gt;Variability in the 3D knee kinematics have been significantly reduced six months post- versus pre-operation. The proposed functional objective assessment method suggests that ACL reconstructive surgery increases joint stability during walking in adolescents.&lt;/p&gt;

무릎밴드 가압과 가온요법이 퇴행성 무릎관절염 노인의 혈류속도에 미치는 효과

The purpose of this study was to investigate the change in blood velocity(mm/sec) when compression and/or heat were applied to the knee joint for the elderly who has both normal and painful legs with osteoarthritis(OA). Experimental compression knee band was prepared from the 3D knee data of the average women in 60's. 3D replica of knee was reduced by 7, 10, and 13% from the nude pattern in course direction. Clothing pressure was measured at the front and back of each healthy and painful knee of elderly women for one minute while standing and sitting on the chair. Blood velocity was measured at 13 cm upper from the mid-patella for 15 minutes. Results are as follows: first, compression or heating treatment itself did not change blood velocity of both legs; second, combination treatment with heating and compression was effective to increase blood velocity. In details, for healthy legs, combination treatments with compression by 10% reduced pattern(about 1.3kPa) and heating(<TEX>$43^{\circ}C$</TEX>) induced the maximal blood velocity, however, for knees with OA, 7% reduced pattern(about 1.0kPa) with simultaneous heating(<TEX>$43^{\circ}C$</TEX>) was more effective than other cases. These results indicated that pain and spasticity of knee joint with OA could be reduced by applying heat and compression therapy, where the compression level of painful knee should be slightly lower than of healthy leg.

Investigation on the kinetic and kinematic characteristics of knee and ankle joints during simulated downhill walking: Implication for ACL injury risk

We investigated 3D kinematic and kinetic changes of knee and ankle during downhill walking as the slope angle increased and evaluated biomechanical injury risk factors related to non-contact ACL injury. Fifteen male subjects performed level walking and 15° and 25° downhill walking. For the kinetic and kinematic parameters, one-way ANOVA and post-hoc tests were performed at a significance level of 0.05. This study revealed significant differences in 3D knee and ankle kinematics and kinetics among 0°, 15° and 25° downhill walking. The peak posterior ground reaction force, the peak knee anterior force and the knee valgus moment (0° vs. 15°: p < 0.05; 0° vs. 25°: p < 0.05) in the early stance phase increased as the slope angle increased. The peak knee internal tibial rotation moments in the late stance also increased (0° vs. 15°: p < 0.05; 0° vs. 25°: p < 0.05; 15° and 25°: p < 0.05) as the slope angle increased. These results showed the risk for ACL injuries may be increased during downhill walking with a greater slope angle.

Data correction to determine a representative pattern of a set of 3D knee kinematic measurements.

The purpose of this study is to determine a representative pattern of a set of three dimensional (3D) knee kinematic measurement curves recorded throughout several trials with a patient walking on a treadmill. The measurements are knee angles, (namely joint angles) with respect to the sagittal, frontal, and transverse planes, as a function of time during a gait cycle. Two serious difficulties met while extracting a representative pattern from the trials are that the curves possess phase variability and there are outliers. We propose a scheme which first removes outliers using the modified band depth index method, and follows with phase variability reduction by curve registration. This scheme leads to retaining the mean curve of the corrected set of curves, as the most representative.

3D knee segmentation based on three MRI sequences from different planes.

In clinical practice, knee MRI sequences with 3.5~5 mm slice distance in sagittal, coronal, and axial planes are often requested for the knee examination since its acquisition is faster than high-resolution MRI sequence in a single plane, thereby reducing the probability of motion artifact. In order to take advantage of the three sequences from different planes, a 3D segmentation method based on the combination of three knee models obtained from the three sequences is proposed in this paper. In the method, the sub-segmentation is respectively performed with sagittal, coronal, and axial MRI sequence in the image coordinate system. With each sequence, an initial knee model is hierarchically deformed, and then the three deformed models are mapped to reference coordinate system defined by the DICOM standard and combined to obtain a patient-specific model. The experimental results verified that the three sub-segmentation results can complement each other, and their integration can compensate for the insufficiency of boundary information caused by 3.5~5 mm gap between consecutive slices. Therefore, the obtained patient-specific model is substantially more accurate than each sub-segmentation results.

Chain-loaded variable resistance warm-up improves free-weight maximal back squat performance

The acute influence of chain-loaded variable resistance exercise on subsequent free-weight one-repetition maximum (1-RM) back squat performance was examined in 16 recreationally active men. The participants performed either a free-weight resistance (FWR) or chain-loaded resistance (CLR) back squat warm-up at 85% 1-RM on two separate occasions. After a 5-min rest, the participants attempted a free-weight 1-RM back squat; if successful, subsequent 5% load additions were made until participants failed to complete the lift. During the 1-RM trials, 3D knee joint kinematics and knee extensor and flexor electromyograms (EMG) were recorded simultaneously. Significantly greater 1-RM (6.2 ± 5.0%; p < .01) and mean eccentric knee extensor EMG (32.2 ± 6.7%; p < .01) were found after the CLR warm-up compared to the FWR condition. However, no difference (p > .05) was found in concentric EMG, eccentric or concentric knee angular velocity, or peak knee flexion angle. Performing a CLR warm-up enhanced subsequent free-weight 1-RM performance without changes in knee flexion angle or eccentric and concentric knee angular velocities; thus a real 1-RM increase was achieved as the mechanics of the lift were not altered. These results are indicative of a potentiating effect of CLR in a warm-up, which may benefit athletes in tasks where high-level strength is required.

The relationship between three-dimensional knee MRI bone shape and total knee replacement-a case control study: data from the Osteoarthritis Initiative.

Objective. There is growing understanding of the importance of bone in OA. Our aim was to determine the relationship between 3D MRI bone shape and total knee replacement (TKR).Methods. A nested case-control study within the Osteoarthritis Initiative cohort identified case knees with confirmed TKR for OA and controls that were matched using propensity scores. Active appearance modelling quantification of the bone shape of all knee bones identified vectors between knees having or not having OA. Vectors were scaled such that −1 and +1 represented the mean non-OA and mean OA shapes.Results. Compared to controls (n = 310), TKR cases (n = 310) had a more positive mean baseline 3D bone shape vector, indicating more advanced structural OA, for the femur [mean 0.98 vs −0.11; difference (95% CI) 1.10 (0.88, 1.31)], tibia [mean 0.86 vs −0.07; difference (95% CI) 0.94 (0.72, 1.16)] and patella [mean 0.95 vs 0.03; difference (95% CI) 0.92 (0.65, 1.20)]. Odds ratios (95% CI) for TKR per normalized unit of 3D bone shape vector for the femur, tibia and patella were: 1.85 (1.59, 2.16), 1.64 (1.42, 1.89) and 1.36 (1.22, 1.50), respectively, all P < 0.001. After including Kellgren–Lawrence grade in a multivariable analysis, only the femur 3D shape vector remained significantly associated with TKR [odds ratio 1.24 (1.02, 1.51)].Conclusion. 3D bone shape was associated with the endpoint of this study, TKR, with femoral shape being most associated. This study contributes to the validation of quantitative MRI bone biomarkers for OA structure-modification trials.

Side Bending Error Test Correlates with Frontal Plane Cutting Mechanics

PURPOSE: Greater frontal plane trunk and knee angles have been implicated in non-contact ACL injury risk in females during jumping and cutting activities. However, proximal positioning is difficult to assess and few clinical tests exist to quantify this risk. The purpose of this study was to assess the relationship between errors in position sense during a new trunk positioning clinical test and 3D coronal plane trunk and knee mechanics during an unanticipated cutting task. METHODS: Female subjects without a history of significant lower extremity injury participated in this study. Subjects were recorded performing an instrumented unanticipated cutting task. While at a run, just prior to hitting a force plate, an indicator light would indicate which direction the subject was to cut. Kinematic variables were recorded for cuts from the planted right leg while cutting to the left. Subjects were then photographed performing a side-bending task while maintaining a single leg stance. The first picture was taken after they had bent to the side touching a prepositioned guide. Then, a second picture was taken as they attempted to position themselves in the same position without the guide. We then calculated the total side bending error by adding the differences between the bending angles to the right and left sides. Pearson product moment correlation coefficients were used to calculate the relationship between side bending error and frontal plane trunk and knee angles. RESULTS: Fourteen females completed the study. The subjects were 22.8±2.8 years old and had an average Tegner Score of 5.8±1.0. Subjects had an average side bending error of 4.6°±1.7°, lateral trunk angle of 3.6°±5.3° and knee abduction angle 4.0°±4.0°. We found correlations of r=0.64 (p=0.014) and r=0.65 (p=0.012) between side bending error and knee abduction angle and lateral trunk lean respectively. CONCLUSION: Female subjects with higher side bending errors were found to have higher knee abduction angles and higher ipsilateral trunk lean angles during an unanticipated cutting task. This study suggests that females who are poorer at accurately placing their body in space, find themselves in positions that put them at risk for ACL injury. The bending error test could be a useful clinical screening tool to identify those most at risk and in need of preventative strategies.

Do Patients’ Perceptions of Leg Length Correlate With Standing 2- and 3-Dimensional Radiographic Imaging?

BackgroundThis study compared 2- and 3-dimensional (2D and 3D) radiographic measurements of anatomical and functional leg length and knee coronal and sagittal alignments and correlated these measurements with patients’ leg-length perceptions. MethodsPatients without symptomatic spinal pathology, previous surgery of the spine, and lower extremities (140 lower extremities) were evaluated on EOS images obtained in standing position. Numerous measurements of each limb were compared to the contralateral limb. All 2D/3D measures were evaluated and compared for repeatability and reproducibility. ResultsMean 2D functional and anatomical lengths were 78.7 cm (64.7-88.4, confidence interval [CI] 95%: 77.4-80) and 78.3 cm (64.9-87.9, CI 95%: 77-79.6), respectively. Mean 3D functional and anatomical lengths were 78.9 cm (65.1-88.7, CI 95%: 77.6-80.2) and 78.9 cm (65.6-88.3, CI 95%: 77.8-80.5), respectively (P < .001). Mean 2D and 3D knee varus/valgus angles were −1.9° (−26.4 to 9.1, CI 95%: −3.5 to −0.7) and −0.9° (−19.2 to 11.8, CI 95%: −2.4 to 0.2), respectively (P = .004). Multiple regression analysis found that patients with >10° of flexum/recurvatum were 2.1× more likely to perceive unequal length (P < .1). Patients with irreducible varus/valgus knee deformity were 4× more likely to perceive unequal length (P < .04). ConclusionEOS imaging allows more accurate assessment of anatomical and functional lengths. Patients’ perceptions of lower extremity length may correlate more closely with coronal and sagittal alignments of the knee than with femoral or tibial length. This study highlights the importance of physical examination of all the joints and 3D measurements in functional standing position.

Cricket pace bowling: The trade-off between optimising knee angle for performance advantages v. injury prevention

Background. The cricket pace bowler utilises various strategies, including a more extended front knee angle, to achieve optimal performance benefits. At times this is done to the detriment of injury prevention.Objective. To investigate the relationship between three-dimensional (3D) knee kinematics during pace bowling action, injury incidence and bowling performance at the start and end of a cricket season.Methods. Knee angle and ball release (BR) speed of injury-free premier league (club level) cricket pace bowlers over the age of 18 years were measured at the start and end of the cricket season. Kinematic, injury- and bowling performance-related (BR speed and accuracy) data were analysed using paired and independent Student's t-tests, Pearson's correlation coefficient,χ2 test and a two-way analysis of covariance with repeated measures.Results. Thirty-one bowlers participated in this study, and kinematic data of a subset of 17 were analysed. Nine bowlers (53%) sustained injuries during the cricket season. No statistically significant relationship was found between knee angle and injury. Bowlers who did not sustain an injury bowled with more knee flexion at the start of the season (mean (standard deviation) 157.07° (12.02°)) than at the end of it (163.95° (6.97°)) (p=0.01). There was no interaction between accuracy and knee angle. There was a good to excellent inverse correlation between BR speed and knee angle among bowlers who remained injury free (r=.0.79; p=0.18).Conclusion. Bowlers who remain injury free during the course of the season may use strategies other than the front knee angle to facilitate high BR speeds. Technique-related variables which are more 'protective' against injuries while allowing for higher BR speeds should be further investigated among bowlers.

The relationship between knee symptoms and 3D MRI knee bone shape: Data from the Osteoarthritis Initiative

The relationship between knee symptoms and 3D MRI knee bone shape: Data from the Osteoarthritis Initiative