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To test whether quadriceps strength is associated with measures of patellofemoral (PF) joint loading during running and hopping in people after an anterior cruciate ligament reconstruction (ACLR). Cross-sectional study. Biomechanics laboratory. Sixty-five participants (24 women; 41 men) 1–2 years post-ACLR. Peak isometric quadriceps strength for the surgical limb was measured using a dynamometer. Motion analysis and ground reaction force data were combined with musculoskeletal modelling to measure PF joint loading variables for the reconstructed knee (peak knee flexion angle; peak/impulse of the PF joint contact force; time to peak PF joint contact force) during the stance phase of running and during the landing phase of a standardised forward hop. Linear regression analysis (adjusting for age and sex) assessed the association between quadriceps strength and PF joint loading variables. Two significant, albeit modest, associations were revealed. Quadriceps strength was associated with the time to peak PF joint contact force during running (β = −0.001; 95%CI -0.002 to −0.000; R2 = 0.179) and the impulse of the PF joint contact force during hopping (β = 0.014; 95%CI 0.003 to 0.024; R2 = 0.159). A strong link between quadriceps strength and PF joint loading was not evident in people 1–2 years post-ACLR. • People after anterior cruciate ligament injury often have weak quadriceps muscles. • They also display altered knee joint loading patterns during functional tasks. • The relationship between quadriceps strength and knee joint loading is tenuous. [ABSTRACT FROM AUTHOR]

Following ACL reconstruction (ACLR), deficits in hip muscle strength and relationships to future outcomes are unknown. 111 participants one year after ACLR, completed hip external rotation (ER) and internal rotation (IR) strength assessment. At 1 (n = 111) and 5 (n = 74) years post-ACLR, participants completed a battery of functional, symptomatic (Knee Osteoarthritis Outcome Score (KOOS)) and structural assessments (radiography, magnetic resonance imaging (MRI)). Cartilage health of the patellofemoral and tibiofemoral compartments was assessed with the semiquantitative MRI Osteoarthritis Knee Score. Hip rotation strength was compared between-limbs, and relationships between hip strength at 1 year and functional, symptomatic and cartilage outcomes at 1 and 5 years were investigated with regression models. The index (ACLR) limb had weaker hip ER (but not IR) strength compared to the contralateral side (standardised mean difference ER = −0.33 (95%CI -0.60, −0.07; IR = −0.11 (95%CI -0.37, 0.15). Greater hip ER and IR strength was associated with superior function at 1 and 5 years, and better KOOS-Patellofemoral symptoms at 5 years. Greater hip ER strength was associated with lower odds of worsening tibiofemoral cartilage lesions at 5 years (odds ratio 0.01, 95%CI 0.00, 0.41). Hip rotation strength may play a role in worsening function, symptoms and cartilage health after ACLR. [ABSTRACT FROM AUTHOR]

Objective: To evaluate if returning to pivoting sport following anterior cruciate ligament reconstruction (ACLR) is associated with longitudinal structural and symptomatic osteoarthritis outcomes.Design: Eighty-one adults aged 18-50 years were followed prospectively 1- to 5-years post-ACLR. Return to pivoting sport was assessed at 1-, 3- and 5-years. Longitudinal changes in osteoarthritis features were evaluated from 1- and 5-year magnetic resonance imaging (MRI)s using MRI Osteoarthritis Knee Score (MOAKS). Radiographic osteoarthritis and self-reported knee symptoms, function and quality of life were assessed using the Osteoarthritis Research Society International (OARSI) atlas and Knee injury Osteoarthritis Outcome Score (KOOS), respectively, at 5 years post-ACLR. Generalised linear models (adjusted for baseline characteristics) assessed whether returning to pivoting sport was associated with risk of worsening osteoarthritis features on MRI, radiographic osteoarthritis and KOOS.Results: Thirty participants returned to pivoting sport 1-year post-ACLR and 50 returned at any time (i.e., 1-, 3- or 5-years). Returning to pivoting sport was not associated with worsening of any MRI osteoarthritis feature (risk ratio (RR) range: 0.59-2.91) or 5-year KOOS (β range: -2.73-3.69). Returning to pivoting sport at 1-year and up to 5-years post-ACLR was associated with a 50% (RR 0.49, 95%CI 0.10-2.37) and 40% (RR 0.60, 95%CI 0.16-2.17) reduced risk of radiographic osteoarthritis, respectively, but these risk reductions were inconclusive due to wide confidence intervals.Conclusion: After ACLR, returning to pivoting sport was not associated with increased risk of worsening knee osteoarthritis features on MRI, radiographic osteoarthritis or knee symptoms. Participation in pivoting sport need not be avoided as part of osteoarthritis secondary prevention strategies. [ABSTRACT FROM AUTHOR]

Objectives: Patellofemoral pain is a frequent and troublesome complication following anterior cruciate ligament reconstruction (ACLR), irrespective of graft source. Yet, little is known about the factors associated with patellofemoral pain following hamstring-tendon ACLR.Design: Retrospective analysis of potential patellofemoral pain predictors, and cross-sectional analysis of possible patellofemoral pain consequences.Methods: Potential predictors (pre-injury patellofemoral pain and activity level, concomitant patellofemoral cartilage damage and meniscectomy, age, sex, and surgical delay) and consequences (hopping performance, quality of life, kinesiophobia, and return to sport rates and attitudes) of patellofemoral pain 12 months following hamstring-tendon ACLR were assessed in 110 participants using univariate and multivariate analyses.Results: Thirty-three participants (30%) had patellofemoral pain at 12 months post-ACLR. Older age at the time of ACLR was the only predictor of post-operative patellofemoral pain. Following ACLR, those with patellofemoral pain had a higher body mass index, and worse physical performance, quality of life, kinesiophobia and return to sport attitudes. Patellofemoral pain has a significant burden on individuals 12 months following hamstring-tendon ACLR.Conclusions: Clinicians need to be cognisant of patellofemoral pain, particularly in older individuals and those with a higher body mass index. The importance of considering psychological factors that are not typically addressed during ACLR rehabilitation, such as kinesiophobia, quality of life and return to sport attitudes is emphasised. [ABSTRACT FROM AUTHOR]

Abstract: Throughout the world a number of testing systems are used to obtain the fertiliser spread pattern from spinning disc spreaders. Results of these tests are used to certify the bout width, which is the permitable distance between adjacent transects of the spreader truck across the field. These tests use trays aligned in one or two transverse rows to the direction of travel of the spreader which collects the fertiliser for one or more passes by the spreading vehicle. The tray size, their spacing in each row, the distance apart between transverse rows, and the number of passes all vary between tests. In this study, a field trial was constructed to simulate all international tests. The ground was covered with 0.5×0.5 m trays arranged as 18 transverse rows of 80 trays each, leaving spaces for the truck wheels. The amount of fertiliser landing on each tray was weighed for two replicates at each of three nominal application rates of 80, 100 and 150 kg ha−1 of urea. These trials provide good sample statistics, which are used to estimate the confidence limits of the spread patterns for each international spread test and then to estimate the accuracy of correctly certifying the bout width. The ACCU Spread (Australia) method proved far superior in both aspects; it had the narrowest confidence limits for the spread pattern and the most accurate determination of bout width, which it could predict accurately to within one tray, or 0.5 m. The ES (Europe) method was next best, but is prone to a ‘near neighbour effect’ because the two adjacent rows of trays cannot be guaranteed to have longitudinal independence. Next were the ISO 5690/1, ISO 5690/2 and Spreadmark (New Zealand) tests, which all performed equally well. Interestingly, the ISO 5690/2 test uses a narrower tray (0.25×1.0 m) intended to obtain better transverse resolution, but this did not improve the accuracy of the bout width calculation. The ASAE (USA) method collects only sparse data because the trays are spaced at wide intervals across the swath, which make bout width calculations difficult without interpolation or weighting techniques. This work clearly demonstrates that multiple rows of trays, multiple passes of the spreader and long trays can enhance the accuracy of the test. [Copyright &y& Elsevier]

Purpose: We described patellofemoral alignment and trochlear morphology at one and five years after anterior cruciate ligament reconstruction (ACLR), and evaluated the associations between alignment and trochlear morphology (at one year) and worsening patellofemoral osteoarthritis (OA) features by five years. We also evaluated the associations between alignment and morphology to self-reported pain and function (Knee injury and Osteoarthritis Outcome Score, KOOS) at five years.Materials and Methods: In this longitudinal observational study, we followed 73 participants (mean age 29[9] years, 40% women) from one- to five-years after ACLR. Using MRI, we measured alignment and morphology, and scored cartilage and bone marrow lesions at both time points. We used mixed effects and linear regression models to achieve our stated aims.Results: Greater lateral patella displacement increased risk of cartilage worsening (Odds Ratio [95% CI]: 1.09 [1.01, 1.16]); while less lateral tilt (0.91 [0.83, 0.99]) and greater trochlear angle (0.88 [0.77, 1.00]) were protective. Greater medial trochlear inclination increased risk of bone marrow lesion worsening (1.12 [1.04, 1.19]); while greater trochlear angle was protective (0.80 [0.67, 0.96]). Greater lateral displacement was associated with worse self-reported KOOS sport and recreation scores (β [95% CI]: -11.0 [-20.9, -1.2]) and quality of life scores (-10.5 [-20.4, -0.7]).Conclusions: Lateral displacement, lateral tilt, and morphology at 1 year post-ACLR altered the risk of worsening patellofemoral OA features four years later. Lateral displacement was the only measure associated with worse self-reported symptoms at five years. These findings may lead to novel treatment strategies for secondary prevention after ACLR. [ABSTRACT FROM AUTHOR]

Following anterior cruciate ligament (ACL) rupture, reconstructive surgery (ALCR) is often performed to mechanically stabilise the knee, however functional deficits often persist long after surgery. Impaired single-limb standing balance has been observed in the ACLR limb compared to healthy individuals. However, it remains inconclusive as to whether these same balance deficits exist between the injured and contralateral uninjured limbs, during challenging balance tasks, and at a time when patients are permitted to return to sport. 100 adults who had undergone a primary hamstring-tendon ACLR 12 months previously (68 male; median[IQR] age: 28.1[14.1] years) performed tests of single-limb standing with the knee in a functional position of 20-30° flexion, with their eyes closed, over 20s (Nintendo Wii Balance Board). Two repetitions were performed on the ACLR and uninjured limb. Measures of postural control included centre of pressure (CoP) path velocity, anterior-posterior and mediolateral range and standard deviation, and were averaged across the two trials. Wilcoxon signed-rank tests showed no significant between-leg differences in single-limb balance for any of the CoP measures of interest (all P values>0.686). Further, multiple linear regression analyses showed no significant associations between concomitant meniscectomy or chondral lesions noted at the time of ACLR and measures of single-limb balance on the ACLR limb one year later (all P values>0.213). In the context of prior research, these findings suggest bilateral balance deficits may exist prior to ACL injury, or appear post ACL-injury or ACLR. Treatment of balance deficits should therefore consider both limbs after ACLR. [ABSTRACT FROM AUTHOR]