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Early identification of knee osteoarthritis (OA) symptoms after anterior cruciate ligament reconstruction (ACLR) could enable timely interventions to improve long-term outcomes. However, little is known about the change in early OA symptoms from 6 to 12 months post-ACLR. To evaluate the change over time in meeting classification criteria for early knee OA symptoms from 6 to 12 months after ACLR. Prospective cohort study. Research laboratory. Eighty-two participants aged 13 to 35 years who underwent unilateral primary ACLR. On average, participants' first and second visits were 6.2 and 12.1 months post-ACLR. Early OA symptoms were classified using generic (Luyten Original) and patient population–specific (Luyten Patient Acceptable Symptom State [PASS]) thresholds on Knee injury and Osteoarthritis Outcome Score (KOOS) subscales. Changes in meeting early OA criteria were compared between an initial and follow-up visit at an average of 6 and 12 months post-ACLR, respectively. Twenty-two percent of participants exhibited persistent early OA symptoms across both visits using both the Luyten Original and PASS criteria. From initial to follow-up visit, 18% to 27% had resolution of early OA symptoms, while 4% to 9% developed incident symptoms. In total, 48% to 51% had no early OA symptoms at either visit. No differences were found for change in early OA status between adults and adolescents. Nearly one-quarter of participants exhibited persistent early knee OA symptoms based on KOOS thresholds from 6 to 12 months post-ACLR. Determining if this symptom persistence predicts worse long-term outcomes could inform the need for timely interventions after ACLR. Future researchers should examine if resolving persistent symptoms in this critical window improves later outcomes. Tracking early OA symptoms over time may identify high-risk patients who could benefit from early treatment. [ABSTRACT FROM AUTHOR]

The objective of this study was to determine the optimal meniscal radiomic features to classify people who will develop an incident destabilizing medial meniscal tear. We used magnetic resonance (MR) images from an existing case–control study that includes images from the first 4 years of the Osteoarthritis Initiative (OAI). For this exploratory analysis (n = 215), we limited our study sample to people with (1) intact menisci at the OAI baseline visit, (2) 4‐year meniscal status data, and (3) complete meniscal data from each region of interest. Incident destabilizing meniscal tear was defined as progressing from an intact meniscus to a destabilizing tear by the 48‐month visit using intermediate‐weighted fat‐suppressed MR images. One reader manually segmented each participant's anterior and posterior horn of the medial menisci at the OAI baseline visit. Next, 61 different radiomic features were extracted from each medial meniscus horn. We performed a classification and regression tree (CART) analysis to determine the classification rules and important variables that predict incident destabilizing meniscal tear. The CART correctly classified 24 of the 34 cases and 172 out of 181 controls with a sensitivity of 70.6% and a specificity of 95.0%. The CART identified large zone high gray level emphasis (i.e., more coarse texture) from the posterior horn as the most important variable to classify who would develop an incident destabilizing medial meniscal tear. The use of radiomic features provides sensitive and quantitative measures of meniscal alterations, allowing us to intervene and prevent destabilizing meniscal tears. [ABSTRACT FROM AUTHOR]

Visuomotor reaction time (VMRT) is predictive of lower-extremity musculoskeletal injury and may be a modifiable anterior cruciate ligament (ACL) injury risk factor that affects the incidence of primary and secondary ACL injuries in females. However, it is unknown if females with ACL reconstruction (ACLR) experience diminished VMRT compared with their male counterparts. The purpose of this study was to compare lower-extremity VMRT (LEVMRT) between males and females with ACLR. Female (n = 40) and male (n = 20) participants who were between 4 and 12 months after primary, unilateral ACLR completed a LEVMRT task with each limb using a series of wireless light discs. Mann–Whitney U tests were used to compare between-group differences for LEVMRT (in milliseconds). No statistically significant sex differences were observed for LEVMRT when the ACLR limb deactivated the light discs (females = 509.5 [132.5], males = 507.0 [79.8]; p =.77) or when the ACLR limb was stabilizing while the nonsurgical limb deactivated the light discs (females = 528.5 [105.3], males = 546.0 [92.5]; p =.77). Both males and females may benefit from visual motor training to improve VMRT after ACLR. [ABSTRACT FROM AUTHOR]

To determine the association between change in physical activity level, as defined as the change from pre-to post-operative Tegner Activity Scale, and quality of life (QOL) after anterior cruciate ligament reconstruction (ACLR), before patients are cleared for return to sport. 1198 participants (42.9% male; 18.7 ± 3.6 years; 7.1 ± 3.7 months post-ACLR). Surveys included Knee Injury and Osteoarthritis Outcome Score QOL (KOOS-QOL) subscale and Tegner Activity Scale. KOOS-QOL score ≥62.5 is considered as meeting a previously established patient acceptable symptom state. The acceptable KOOS-QOL group reported a significantly smaller decrease in activity level from pre-injury to time of data collection (median: 2.00, IQR: 2.00) than the unacceptable KOOS-QOL group (median: 3.00, IQR: 3.00). Across the full cohort, for every one-point larger decrease in Tegner score from pre-to post-ACLR, there is a 52% increase in the odds of having an unacceptable KOOS-QOL score. For adolescents, the odds increase to 60% while the odds for adults were lower at 39%. Following ACLR, greater decreases in physical activity level are associated with poorer QOL for both adolescents and adults at short-term follow-up, and this effect is larger amongst adolescents. • Decreased physical activity is associated with worse quality of life after ACLR. • This effect is greater in adolescents than in adults. • Returning to physical activity is important for short-term quality of life. [ABSTRACT FROM AUTHOR]

Arthrogenic muscle inhibition (AMI) is a common impairment in individuals who sustain an anterior cruciate ligament (ACL) injury. The AMI causes decreased muscle activation, which impairs muscle strength, leading to aberrant movement biomechanics. The AMI is often resistant to traditional rehabilitation techniques, which leads to persistent neuromuscular deficits following ACL reconstruction. To better treat AMI following ACL injury and ACL reconstruction, it is important to understand the specific neural pathways involved in AMI pathogenesis, as well as the changes in muscle function that may impact movement biomechanics and long-term structural alterations to joint tissue. Overall, AMI is a critical factor that limits optimal rehabilitation outcomes following ACL injury and ACL reconstruction. This review discusses the current understanding of the: (1) neural pathways involved in the AMI pathogenesis following ACL injury; (2) consequence of AMI on muscle function, joint biomechanics, and patient function; and (3) development of posttraumatic osteoarthritis. Finally, the authors review the evidence for interventions specifically used to target AMI following ACL injury. [ABSTRACT FROM AUTHOR]

This study aimed to create a conversion equation that accurately predicts cartilage magnetic resonance imaging (MRI) T2 relaxation times using ultrasound echo‐intensity and common participant demographics. We recruited 15 participants with a primary anterior cruciate ligament reconstruction between the ages of 18 and 35 years at 1–5 years after surgery. A single investigator completed a transverse suprapatellar scan with the ACLR limb in max knee flexion to image the femoral trochlea cartilage. A single reader manually segmented the femoral cartilage cross‐sectional area to assess the echo‐intensity (i.e., mean gray‐scale pixel value). At a separate visit, a T2 mapping sequence with the MRI beam set to an oblique angle was used to image the femoral trochlea cartilage. A single reader manually segmented the cartilage cross‐sectional area on a single MRI slice to assess the T2 relaxation time. A stepwise, multiple linear regression was used to predict T2 relaxation time from cartilage echo‐intensity and common demographic variables. We created a conversion equation using the regression betas and then used an ICC and Bland–Altman plot to assess agreement between the estimated and true T2 relaxation time. Cartilage ultrasound echo‐intensity and age significantly predicted T2 relaxation time (F = 7.33, p = 0.008, R2 = 0.55). When using the new conversion equation to estimate T2 relaxation time from cartilage echo‐intensity and age, there was strong agreement between the estimated and true T2 relaxation time (ICC2,k = 0.84). This study provides promising preliminary data that cartilage echo‐intensity combined with age can be used as a clinically accessible tool for evaluating cartilage composition. [ABSTRACT FROM AUTHOR]

Objective: The objective of this study was to compare the vertical (vGRF), anterior‐posterior (apGRF), and medial‐lateral (mlGRF) ground reaction force (GRF) profiles throughout the stance phase of gait (1) between individuals 6 to 12 months post–anterior cruciate ligament reconstruction (ACLR) and uninjured matched controls and (2) between ACLR and individuals with differing radiographic severities of knee osteoarthritis (KOA), defined as Kellgren and Lawrence (KL) grades KL2, KL3, and KL4. Methods: A total of 196 participants were included in this retrospective cross‐sectional analysis. Gait biomechanics were collected from individuals 6 to 12 months post‐ACLR (n = 36), uninjured controls matched to the ACLR group (n = 36), and individuals with KL2 (n = 31), KL3 (n = 67), and KL4 osteoarthritis (OA) (n = 26). Between‐group differences in vGRF, apGRF, and mlGRF were assessed in reference to the ACLR group throughout each percentage of stance phase using a functional linear model. Results: The ACLR group demonstrated lower vGRF and apGRF in early and late stance compared to the uninjured controls, with large effects (Cohen's d range: 1.35–1.66). Conversely, the ACLR group exhibited greater vGRF (87%–90%; 4.88% body weight [BW]; d = 0.75) and apGRF (84%–94%; 2.41% BW; d = 0.79) than the KL2 group in a small portion of late stance. No differences in mlGRF profiles were observed between the ACLR and either the uninjured controls or the KL2 group. The magnitude of difference in GRF profiles between the ACLR and OA groups increased with OA disease severity. Conclusion: Individuals 6 to 12 months post‐ACLR exhibit strikingly similar GRF profiles as individuals with KL2 KOA, suggesting both patient groups may benefit from targeted interventions to address aberrant GRF profiles. [ABSTRACT FROM AUTHOR]

The objective of this study was to assess the prognostic potential of magnetic resonance (MR)‐detected meniscal degeneration in relation to incident destabilizing meniscal tears (radial, complex, root, or macerated) or accelerated knee osteoarthritis (AKOA). We used existing MR data from a case‐control study of three groups from the Osteoarthritis Initiative without radiographic KOA at baseline: AKOA, typical KOA, and no KOA. From these groups, we included people without medial and lateral meniscal tear at baseline (n = 226) and 48‐month meniscal data (n = 221). Intermediate‐weighted fat‐suppressed MR images annually from baseline to the 48‐month visit were graded using a semiquantitative meniscal tear classification criterion. Incident destabilizing meniscal tear was defined as progressing from an intact meniscus to a destabilizing tear by the 48‐month visit. We used two logistic regression models to assess whether: (1) presence of medial meniscal degeneration was associated with an incident medial destabilizing meniscal tear, and (2) presence of meniscal degeneration in either meniscus was associated with incident AKOA over the next 4 years. People with the presence of a medial meniscal degeneration had three times the odds of developing an incident destabilizing medial meniscal tear within 4 years compared with a person without medial meniscus degeneration (odds ratio [OR]: 3.03; 95% confidence interval [CI]: 1.40–6.59). People with meniscal degeneration had five times the odds of developing incident AKOA within 4 years compared with a person without meniscal degeneration in either meniscus (OR: 5.04; 95% CI: 2.57–9.89). Meniscal degeneration on MR is clinically meaningful as it relates to future poor outcomes. [ABSTRACT FROM AUTHOR]

Context: Ultrasound imaging is a clinically feasible tool to assess femoral articular cartilage and may have utility in tracking early knee osteoarthritis development. Traditional assessment techniques focus on measurements at a single location, which can be challenging to adopt for novice raters. Objective: To introduce a novel semiautomated ultrasound segmentation technique and determine the intrarater and interrater reliability of average regional femoral articular cartilage thickness and echo intensity of a novice and expert rater. Design: Descriptive observational study. Setting: Orthopedic clinic. Patients or Other Participants: Fifteen participants (mean [SD]; age 23.5 [4.6] y, height = 172.6 [9.3] cm, mass = 79.8 [15.7] kg) with a unilateral history of anterior cruciate ligament reconstruction participated. Intervention: None. Main Outcome Measures: One rater captured anterior femoral cartilage images of the participants’ contralateral knees using a transverse suprapatellar ultrasound assessment. The total femoral cartilage cross-sectional area of each image was segmented by a novice and expert rater. A novel custom program automatically separated the cartilage segmentations into medial, lateral, and intercondylar regions to determine the crosssectional area and cartilage length. The average cartilage thickness in each region was calculated by dividing the cross-sectional area by the cartilage length. Echo intensity was calculated as the average gray-scale pixel value of each region. Two-way random effect intraclass correlations coefficient (ICC) for absolute agreement were used to determine the interrater reliability between a novice and expert rater, as well as the intrarater reliability of the novice rater. Results: The novice rater demonstrated excellent intrarater (ICC [2,k] range = .993–.997) and interrater (ICC [2,k] range = .944–.991) reliability with the expert rater of all femoral articular cartilage average thickness and echo intensity regions. Conclusions: The novel semiautomated average cartilage thickness and echo-intensity assessment is efficient, systematic, and reliable between an expert and novice rater with minimal training. [ABSTRACT FROM AUTHOR]

Background: Treatment of meniscal injuries at the time of anterior cruciate ligament reconstruction (ACLR) can result in restrictions on weightbearing and range of motion in the early rehabilitative phases. What is unknown is the effect of (1) meniscal tear type and location at the time of anterior cruciate ligament injury and (2) meniscal treatment at the time of ACLR on quadriceps strength in adolescents during the late rehabilitative phase. Hypothesis: Meniscal tears involving the root and requiring repair would adversely affect quadriceps strength at 6 to 9 months postoperatively. Study Design: Cohort study; Level of evidence, 3. Methods: Patients who underwent ACLR at 1 of 2 research sites between 2013 and 2021 were identified. Adolescent participants were included if they were between the ages of 12 and 20 years at the time of assessment and had undergone primary unilateral ACLR in the previous 6 to 9 months. Participants were subgrouped by meniscal tear type (no tear, nonroot tear, root tear) and meniscal treatment at the time of ACLR (no treatment, meniscectomy, meniscal repair), which were confirmed via chart review. Isokinetic strength testing occurred at 60 deg/s, and quadriceps strength and quadriceps strength limb symmetry index were compared between the meniscal tear type and meniscal procedure subgroups using analysis of covariance while controlling for the effects of age, sex, and ACLR graft source. Results: An overall 236 patients were included in this analysis (109 male, 127 female; mean ± SD age, 16.0 ± 1.9 years). There were no significant differences in ACLR limb quadriceps strength based on meniscal tear type (P =.61) or meniscal procedure at the time of ACLR (P =.61), after controlling for age, biological sex, and ACLR graft source. Similarly, quadriceps strength limb symmetry index did not differ by meniscal tear type (P =.38) or meniscal procedure at the time of ACLR (P =.40). Conclusion: Meniscal tear type and treatment at the time of ACLR did not affect quadriceps strength or quadriceps strength symmetry in adolescents 6 to 9 months after ACLR. [ABSTRACT FROM AUTHOR]

* OBJECTIVE: To describe age-, sex-, and graft source-specific reference values for patient-reported, physical function, and strength outcome measures in adolescents at 5 to 7 months after anterior cruciate ligament reconstruction. * DESIGN: Cross-sectional study. * METHODS: Data were collected at 3 universities and 2 children's hospitals. The participants completed at least one of the International Knee Documentation Committee (IKDC) Subjective Evaluation Form, Pediatric IKDC (Pedi-IKDC), Knee Injury and Osteoarthritis Outcomes Score (KOOS), and Anterior Cruciate Ligament Return to Sport After Injury (ACL-RSI) Scale. Participants also completed single-leg hop tests and/ or isokinetic quadriceps and hamstrings strength assessments (at 60°/s). Reference values were summarized using descriptive statistics and stratified for age, sex, and graft source. * RESULTS: Reference values were reported for common patient-reported outcomes and measures of physical function and strength from 783 participants (56% females, age = 16. 4 ± 2.0 years) who were in early adolescence (12-14 years, N = 183, 52% females), middle adolescence (15-17 years, N = 456, 58% females), or late adolescence (18-20 years, N = 144, 55% females). Three hundred seventy-nine participants (48.4%) received a bone-patellar tendon-bone autograft, 292 participants (37.3%) received hamstring tendon autograft, and 112 participants (14.3%) received autograft or allograft from an alternative source. * CONCLUSION: Reference values for common patient-reported outcomes and measures of physical function and strength differed depending on a patient's age, sex, and graft source. Using patient-specific reference values, in addition to previously described age-appropriate cutoff values, may help clinicians monitor and progress patients through rehabilitation and return to physical activity after anterior cruciate ligament reconstruction. [ABSTRACT FROM AUTHOR]

Individuals with anterior cruciate ligament reconstruction and early knee osteoarthritis symptoms commonly exhibit psychological impairments, such as pain catastrophizing. Pain catastrophizing is a negative cognitive–affective response to anticipated or actual pain and has been linked to greater pain intensity and decreased function in this population. However, an examination of the neuromatrix theory of pain and the transactional theory of stress and coping may help to explain the development and consequences of pain catastrophizing in individuals with anterior cruciate ligament reconstruction and early knee osteoarthritis symptoms. Exploration of these theoretical models will help clinicians better understand the impact of pain catastrophizing on post-injury outcomes, as well as help to identify intervention strategies to address maladaptive psychological responses and improve outcomes for individuals with anterior cruciate ligament reconstruction and early knee osteoarthritis symptoms. [ABSTRACT FROM AUTHOR]

Objective: To assess the relationship between walking for exercise and symptomatic and structural disease progression in individuals with knee osteoarthritis (OA). Methods: We assessed a nested cohort of participants age 50 years or older within the Osteoarthritis Initiative, a community‐based observational study in which subjects were enrolled between 2004 and 2006. We focused on 4 dichotomous outcomes from baseline to the 48‐month visit, involving determination of the frequency of knee pain and radiographic severity of knee OA on posteroanterior semiflexed knee radiographs. The outcomes assessed included 1) new frequent knee pain, 2) worsening of radiographic severity of knee OA based on the Kellgren/Lawrence grade, 3) progression of medial joint space narrowing, and 4) improved frequent knee pain. We used a modified version of the Historical Physical Activity Survey Instrument to ascertain those subjects who reported walking for exercise after age 50 years. The survey was administered at the 96‐month visit (2012–2014). Results: Of 1,212 participants with knee OA, 45% were male and 73% reported walking for exercise. The mean ± SD age was 63.2 ± 7.9 years, and the mean ± SD body mass index was 29.4 ± 4.6 kg/m2. The likelihood of new frequent knee pain was reduced in participants with knee OA who walked for exercise as compared to those who were non‐walkers (odds ratio [OR] 0.6, 95% confidence interval [95% CI] 0.4–0.8), and progression of medial joint space narrowing was less common in walkers compared to non‐walkers (OR 0.8, 95% CI 0.6–1.0). Conclusion: In individuals with knee OA who were age 50 years or older, walking for exercise was associated with less frequent development of knee pain. These findings support the notion that walking for exercise should be encouraged for people with knee OA. Furthermore, we offer a proof of concept that walking for exercise could be disease modifying, which warrants further study. [ABSTRACT FROM AUTHOR]

Objective: Occupations involving greater physical activity may increase risk for knee osteoarthritis (OA). Existing studies have not evaluated work-related physical activity before OA onset. Hence, we aimed to evaluate the association between work-related physical activity and knee OA incidence.Methods: We performed a person-based longitudinal study using Osteoarthritis Initiative (OAI) data among people who volunteered or worked for pay without baseline radiographic knee OA or knee pain. Bilateral knee radiographs were obtained at baseline and annual follow-ups. We defined radiographic OA as Kellgren-Lawrence grade ≥2. Questions from the Physical Activity Scale for the Elderly at baseline and annual OAI visits provided information about work-related physical activity level and hours. We performed logistic regression with work-related physical activity level ( mainly sitting , standing and some walking , walking while handling some materials ) and hours as predictors. The outcome was incident person-based radiographic OA within the ensuing 12 months, over 48 months.Results: Among 951 participants (2819 observations), higher work-related physical activity levels had greater adjusted ORs for incident radiographic OA (people with jobs with standing and some walking : 1.11 (0.60-2.08), and walking while handling some materials : 1.90 (1.03-3.52), when compared with those with mainly sitting work-related activity ). There was no association between number of hours worked and incident radiographic OA.Conclusions: People performing work that require walking while handling some materials have greater odds of incident knee OA than those with jobs mostly involving sitting. Strategies are needed to mitigate risk factors predisposing them to radiographic OA. [ABSTRACT FROM AUTHOR]

Repetitive joint use is a risk factor for osteoarthritis, which is a leading cause of disability. Sports requiring a racket or bat to perform repetitive high-velocity impacts may increase the risk of thumb-base osteoarthritis. However, this hypothesis remains untested. To determine if a history of participation in racket or bat sports was associated with the prevalence of thumb-base osteoarthritis. Descriptive epidemiologic study. Four US clinical sites associated with the Osteoarthritis Initiative. We recruited 2309 men and women from the community. Eligible participants had dominant-hand radiographic readings, hand symptom assessments, and historical physical activity survey data. A history of exposure to racket or bat sports (badminton, baseball or softball, racketball or squash, table tennis [or ping pong], tennis [doubles], or tennis [singles]) was based on self-reported recall data covering 3 age ranges (12–18, 19–34, and 35–49 years). Prevalent radiographic thumb-base osteoarthritis was defined as Kellgren-Lawrence grade >2 in the first carpometacarpal joint or scaphotrapezoidal joint at the Osteoarthritis Initiative baseline visit. Symptomatic thumb-base osteoarthritis was defined as radiographic osteoarthritis and hand or finger symptoms. Radiographic or symptomatic thumb-base osteoarthritis was present in 355 (34%) and 56 (5%), respectively, of men (total = 1049) and 535 (42%) and 170 (13%), respectively, of women (total = 1260). After adjusting for age, race, and education level, we found no significant associations between a history of any racket or bat sport participation and thumb-base osteoarthritis (radiographic or symptomatic; odds ratios ranged from 0.82 to 1.34). In a community-based cohort, a self-reported history of participation in racket or bat sports was not associated with increased odds of having radiographic or symptomatic thumb-base osteoarthritis in the dominant hand. [ABSTRACT FROM AUTHOR]

Objective: To compare the prevalence of participants meeting different patient‐reported criteria for early osteoarthritis (OA) illness after anterior cruciate ligament reconstruction (ACLR). Methods: Participants completed the Knee Injury and Osteoarthritis Outcomes Score (KOOS) at a single time point 5.0–7.9 months post‐ACLR. We used established KOOS subscale criteria (i.e., Luyten original and Englund original) to define patient‐reported early OA illness. A two‐by‐two contingency table and McNemar's test were used to compare the prevalence of participants who met the Luyten original versus Englund original KOOS criteria for early OA illness. These analyses were repeated using KOOS subscale thresholds based on established population‐specific patient acceptable symptom state (PASS) within the Luyten and Englund KOOS criteria (i.e., Luyten PASS and Englund PASS). Results: A greater prevalence of participants with ACLR met the Luyten original criteria (n = 165 [54%]) compared to those who met the Englund original criteria (n = 128 [42%]; χ2 = 19.3, P < 0.001). When using the KOOS subscale PASS as thresholds, a significantly greater prevalence of participants with ACLR met the Luyten PASS criteria (n = 133 [43%]) compared to those who met the Englund PASS criteria (n = 85 [28%]; χ2 = 48.0, P < 0.001). When combining the Luyten and Englund KOOS criteria and using the original/PASS subscale thresholds, respectively, 40%/57% of participants met neither, 24%/15% met only 1, and 36%/28% met both KOOS criteria. Conclusion: Regardless of the classification criteria used to define early OA illness, it is concerning that 28–54% of patients report considerable symptoms ~6 months post‐ACLR. Our findings will improve the classification criteria to define early OA illness, which may raise awareness for the need of population‐specific criteria. [ABSTRACT FROM AUTHOR]

Hypertrophy of the infrapatellar fat pad (IFP) in idiopathic knee osteoarthritis has been linked to deleterious synovial changes and joint pain related to mechanical tissue impingement. Yet little is known regarding the IFP's volumetric changes after anterior cruciate ligament reconstruction (ACLR). To examine changes in IFP volume between 6 and 12 months after ACLR and determine associations between patient-reported outcomes and IFP volume at each time point as well as the volume change over time. In a subset of individuals, we examined interlimb IFP volume differences 12 months post-ACLR. Prospective cohort study. Laboratory. We studied 26 participants (13 women, 13 men, age = 21.88 ± 3.58 years, body mass index = 23.82 ± 2.21 kg/m2) for our primary aims and 13 of those participants (8 women, 5 men, age = 21.15 ± 3.85 years, body mass index = 23.01 ± 2.01 kg/m2) for our exploratory aim. Using magnetic resonance imaging, we evaluated the IFP volume change between 6 and 12 months post-ACLR in the ACLR limb and between-limbs differences at 12 months in a subset of participants. International Knee Documentation Committee subjective knee evaluation (IKDC) scores were collected at 6-month and 12-month follow-ups, and associations between IFP volume and patient-reported outcomes were determined. The IFP volume in the ACLR limb increased from 6 months (19.67 ± 6.30 cm3) to 12 months (21.26 ± 6.91 cm3) post-ACLR. Greater increases of IFP volume between 6 and 12 months were significantly associated with better 6-month IKDC scores (r =.44, P =.03). The IFP volume was greater in the uninjured limb (22.71 ± 7.87 cm3) than in the ACLR limb (20.75 ± 9.03 cm3) 12 months post-ACLR. The IFP volume increased between 6 and 12 months post-ACLR; however, the IFP volume of the ACLR limb remained smaller than that of the uninjured limb at 12 months. In addition, those with better knee function 6 months post-ACLR demonstrated greater increases in IFP volume between 6 and 12 months post-ACLR. This suggests that greater IFP volumes may play a role in long-term joint health after ACLR. [ABSTRACT FROM AUTHOR]

We assessed whether pre-operative femoral cartilage thickness and echo intensity on ultrasound are different between individuals who are symptomatic (n = 6) and asymptomatic (n = 7) at 1 year after a primary unilateral anterior cruciate ligament (ACL) reconstruction (age, 23 ± 4 y; 31% women, 69% men; body mass index, 24.9 ± 3.7 kg/m2). A pre-operative, bilateral ultrasound assessment was used to quantify average thickness and echo intensity in the medial, middle and lateral femoral trochlear regions. An inter-limb ratio (ACL/contralateral limb) was calculated for average thickness and echo intensity. At 1 y after ACL reconstruction, we operationally defined the presence of symptoms as scoring ≤85% on at least two Knee Injury and Osteoarthritis Outcome Score subscales. Independent-sample t-tests and Cohen's d effect sizes were used to compare ultrasound pre-operative inter-limb ratios between participants with and without symptoms at 1 y after ACL reconstruction. For medial femoral cartilage, symptomatic participants had significantly greater average cartilage thickness inter-limb ratios (p = 0.01, d = -1.65) and significantly lower echo intensity inter-limb ratios (p = 0.01, d = 1.72) compared with asymptomatic participants. Middle and lateral femoral cartilage average thickness and echo intensity were not different between symptomatic and asymptomatic participants. These findings provide preliminary evidence that a clinically feasible ultrasound assessment of the femoral trochlear cartilage may be prognostic of self-reported symptoms at 1 y after ACL reconstruction. [ABSTRACT FROM AUTHOR]

Background: Osteoarthritis is generally a slowly progressive disorder. However, at least 1 in 7 people with incident knee osteoarthritis develop an abrupt progression to advanced-stage radiographic disease, many within 12 months. We summarize what is known - primarily based on findings from the Osteoarthritis Initiative - about the risk factors and natural history of accelerated knee osteoarthritis (AKOA) - defined as a transition from no radiographic knee osteoarthritis to advanced-stage disease < 4 years - and put these findings in context with typical osteoarthritis (slowly progressing disease), aging, prior case reports/series, and relevant animal models. Risk factors in the 2 to 4 years before radiographic manifestation of AKOA (onset) include older age, higher body mass index, altered joint alignment, contralateral osteoarthritis, greater pre-radiographic disease burden (structural, symptoms, and function), or low fasting glucose. One to 2 years before AKOA onset people often exhibit rapid articular cartilage loss, larger bone marrow lesions and effusion-synovitis, more meniscal pathology, slower chair-stand or walking pace, and increased global impact of arthritis than adults with typical knee osteoarthritis. Increased joint symptoms predispose a person to new joint trauma, which for someone who develops AKOA is often characterized by a destabilizing meniscal tear (e.g., radial or root tear). One in 7 people with AKOA onset subsequently receive a knee replacement during a 9-year period. The median time from any increase in radiographic severity to knee replacement is only 2.3 years. Despite some similarities, AKOA is different than other rapidly progressive arthropathies and collapsing these phenomena together or extracting results from one type of osteoarthritis to another should be avoided until further research comparing these types of osteoarthritis is conducted. Animal models that induce meniscal damage in the presence of other risk factors or create an incongruent distribution of loading on joints create an accelerated form of osteoarthritis compared to other models and may offer insights into AKOA.Conclusion: Accelerated knee osteoarthritis is unique from typical knee osteoarthritis. The incidence of AKOA in the Osteoarthritis Initiative and Chingford Study is substantial. AKOA needs to be taken into account and studied in epidemiologic studies and clinical trials. [ABSTRACT FROM AUTHOR]