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Summary 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.

Hamstrings identification and subsequent graft harvest can be made difficult by body habitus and variability in tendon anatomy. We describe a 'sentinel' blood vessel near the insertions of gracilis and semitendinosus to facilitate identification. A prospective study of 100 patients (100 knees) undergoing primary arthroscopic ACL reconstruction (via the anterior approach) with hamstrings graft was conducted. We searched for a 'sentinel' vessel and studied its position, orientation and perpendicular distance from the pes tendons. The 'sentinel' vessel was present in 98/100 knees. It passed from the superficial fascia to the periosteum at the pes insertion at a mean perpendicular distance of 8 mm from the upper border of the pes tendons. The 'sentinel' vessel was a consistent anatomical finding and served as a reliable guide in determining the pes insertion. Identifying this anatomical landmark allowed a small skin incision with limited wound dissection minimising risk of injury to the infra-patellar branch of the saphenous nerve.

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.

Altered biomechanics are frequently observed following anterior cruciate ligament reconstruction (ACLR). Yet, little is known about knee-joint loading, particularly in the patellofemoral-joint, despite patellofemoral-joint osteoarthritis commonly occurring post-ACLR. This study compared knee-joint reaction forces and impulses during the landing phase of a single-leg forward hop in the reconstructed knee of people 12-24 months post-ACLR and uninjured controls. Experimental marker data and ground forces for 66 participants with ACLR (28 ± 6 years, 78 ± 15 kg) and 33 uninjured controls (26 ± 5 years, 70 ± 12 kg) were input into scaled-generic musculoskeletal models to calculate joint angles, joint moments, muscle forces, and the knee-joint reaction forces and impulses. The ACLR group exhibited a lower peak knee flexion angle (mean difference: -6°; 95% confidence interval: [-10°, -2°]), internal knee extension moment (-3.63 [-5.29, -1.97] percentage of body weight × participant height (body weight [BW] × HT), external knee adduction moment (-1.36 [-2.16, -0.56]% BW × HT) and quadriceps force (-2.02 [-2.95, -1.09] BW). The ACLR group also exhibited a lower peak patellofemoral-joint compressive force (-2.24 [-3.31, -1.18] BW), net tibiofemoral-joint compressive force (-0.74 [-1.20, 0.28] BW), and medial compartment force (-0.76 [-1.08, -0.44] BW). Finally, only the impulse of the patellofemoral-joint compressive force was lower in the ACLR group (-0.13 [-0.23, -0.03] body weight-seconds). Lower compressive forces are evident in the patellofemoral- and tibiofemoral-joints of ACLR knees compared to uninjured controls during a single-leg forward hop-landing task. Our findings may have implications for understanding the contributing factors for incidence and progression of knee osteoarthritis after ACLR surgery.

BackgroundNot meeting functional performance criteria increases reinjury risk after ACL reconstruction (ACLR), but the implications for osteoarthritis are not well known.ObjectiveTo determine if poor functional performance post-ACLR is associated with risk of worsening early osteoarthritis features, knee symptoms, function and quality of life (QoL).MethodsSeventy-eight participants (48 men) aged 28±15 years completed a functional performance test battery (three hop tests, one-leg-rise) 1 year post-ACLR. Poor functional performance was defined as ResultsOnly 14 (18%) passed (≥90% LSI on all tests) the functional test battery. Poor functional performance on the battery (all four tests ConclusionOnly one in five participants met common functional performance criteria (≥90% LSI all four tests) 1 year post-ACLR. Poor function on all four tests was associated with a 3.66 times increased risk of worsening patellofemoral BMLs, and generally not associated with decline in self-reported outcomes.

Background: An anterior cruciate ligament (ACL) injury is a well-established risk factor for the long-term development of radiographic osteoarthritis (OA). However, little is known about the early degenerative changes (ie, Purpose: To describe early degenerative changes between 1 and 5 years after ACL reconstruction (ACLR) on magnetic resonance imaging (MRI) and explore participant characteristics associated with these changes. Study Design: Case-control study; Level of evidence, 3. Methods: Seventy-eight participants (48 men; median age, 32 years; median body mass index [BMI], 26 kg/m2) underwent 3.0-T MRI at 1 and 5 years after primary hamstring autograft ACLR. Early tibiofemoral and patellofemoral OA features were assessed with the MRI Osteoarthritis Knee Score. The primary outcome was worsening (ie, incident or progressive) cartilage defects, bone marrow lesions (BMLs), osteophytes, and meniscal lesions. Logistic regression with generalized estimating equations evaluated participant characteristics associated with worsening features. Results: Worsening of cartilage defects in any compartment occurred in 40 (51%) participants. Specifically, worsening in the patellofemoral and medial and lateral tibiofemoral compartments was present in 34 (44%), 8 (10%), and 10 (13%) participants, respectively. Worsening patellofemoral and medial and lateral tibiofemoral BMLs (14 [18%], 5 [6%], and 10 [13%], respectively) and osteophytes (7 [9%], 8 [10%], and 6 [8%], respectively) were less prevalent, while 17 (22%) displayed deteriorating meniscal lesions. Worsening of at least 1 MRI-detected OA feature, in either the patellofemoral or tibiofemoral compartment, occurred in 53 (68%) participants. Radiographic OA in any compartment was evident in 5 (6%) and 16 (21%) participants at 1 and 5 years, respectively. A high BMI (>25 kg/m2) was consistently associated with elevated odds (between 2- and 5-fold) of worsening patellofemoral and tibiofemoral OA features. Conclusion: High rates of degenerative changes occur in the first 5 years after ACLR, particularly the development and progression of patellofemoral cartilage defects. Older patients with a higher BMI may be at particular risk and should be educated about this risk.

Purpose: Patellofemoral osteoarthritis (PFOA) occurs in approximately half of anterior cruciate ligament (ACL)-injured knees within 10–15 years of trauma. Risk factors for post-traumatic PFOA are poorly understood. Patellofemoral alignment and trochlear morphology may be associated with PFOA following ACL reconstruction (ACLR), and understanding these relationships, particularly early in the post-surgical time period, may guide effective early intervention strategies. In this study, patellofemoral alignment and trochlear morphology were investigated in relation to radiographic features of early PFOA 1-year post-ACLR. Methods: Participants (aged 18–50 years) had undergone ACLR approximately 1 year prior to being assessed. Early PFOA was defined as presence of a definite patellofemoral osteophyte on lateral or skyline radiograph. Sagittal and axial plane alignment and trochlear morphology were estimated using MRI. Using logistic regression, the relationship between alignment or morphology and presence of osteophytes was evaluated. Results: Of 111 participants [age 30 ± 8.5; 41 (37%) women], 19 (17%) had definite osteophytes, only two of whom had had patellofemoral chondral lesions noted intra-operatively. One measure of patellar alignment (bisect offset OR 1.1 [95% confidence interval 1.0, 1.2]) and two measures of trochlear morphology (sulcus angle OR 1.1 [1.0, 1.2], trochlear angle OR 1.2 [1.0, 1.5]) were associated with patellofemoral osteophytes. Conclusions: Patellofemoral malalignment and/or altered trochlear morphology were associated with PFOA 1 year following ACLR compared to individuals post-ACLR without these features. Clarifying the role of alignment and morphology in post-traumatic PFOA may contribute to improving early intervention strategies aimed at secondary prevention. Level of evidence: IV.