Knee osteoarthritis (OA) is a chronic degenerative inflammatory-based condition caused by a cascade of different intra-articular molecules including several cytokines. Among the cytokines, prokineticins (PKs) have recently been identified as important mediators of inflammation and pain. This observational study examined the potential involvement of PK2 in degenerative or traumatic knee disease. Fifteen patients presenting knee osteoarthritis (OA group) and 15 patients presenting a traumatic meniscal tear (TM group) were studied. Synovial fluid samples from affected knees were assessed for PK2, IL-10, and TNF-α using the ELISA method. At a long-term follow-up (minimum 5 years, mean = 6.1 years), patients in the TM group underwent clinical re-evaluation with PROMs (Tegner Activity Scale, IKDC, Lysholm, SKV); in addition, X-ray visualization was used to assess the presence of secondary OA. PK2 was detected in synovial fluids of both TM and OA patients and the levels were comparable between the two groups, while IL-10 levels were significantly greater in the OA group than those in TM patients. PK2 levels correlated with those of IL-10. PK2 levels were greater in blood effusions compared to clear samples, did not differ significantly between sexes, nor were they related to differences in weight, height, or injury (meniscal laterality, time since dosing). No correlation was found between PROMs and radiological classifications in patients in the TM group at final follow-up. These data are the first observations of PK2 in synovial fluid following traumatic meniscus injury. These findings suggest possible further prognostic indices and therapeutic targets to limit the development of secondary OA.

Knee muscle strength recovery after anterior cruciate ligament reconstruction (ACLR) is crucial for a safe return to sport (RTS) but it is poorly described in the adolescent population. Therefore, we compared the knee muscle strength at 6 months post-surgery in adults and adolescents. We hypothesized a greater muscular strength in adolescents 6 months after ACLR. This was a retrospective analysis of 55 adolescents (13-18 years old) and 76 adults (19-39 years old) who underwent ACLR with autograft bone-patellar-tendon-bone (BPTB), subjected to isokinetic tests 6 months after surgery. The following outcomes were analyzed: (1) the maximum torque of hamstrings (H) and quadriceps (Q) during flexion and extension at 30°/s normalized by body weight; (2) hamstrings to quadriceps strength ratio (HQ ratio); (3) injured to uninjured leg muscle strength ratio (limb-symmetry index, LSI). Both adults and adolescents produced lower Q torque with the injured leg compared with uninjured, but similar H torque. In adolescents, the injured Q torque and the Q-LSI were higher compared with adults. In both populations, the Q-LSI was lower than the H-LSI and the HQ ratio in the injured leg was higher compared with uninjured. Adolescents showed a lower HQ ratio in injured legs. At 6 months after ACLR both adolescents and adults did not recover Q strength in the injured leg. However, adolescents showed larger Q strength compared with adults. The HQ ratio analysis showed that 6 months after surgery both groups are not ready for a safe RTS.

Purpose: Paediatric musculoskeletal injuries in association with increased participation in sports activities continue to increase. Arthroscopy is recognized as a safe and effective procedure in children. This study aims to identify trends in European paediatric sports centres over 20 years. Methods: A survey was performed across the European Paediatric Orthopaedic Society (EPOS) Sports Study Group focusing on 3 years (2000, 2009 and 2019). Centres were divided into two groups: Group 1 ( n = 5, with data for 2000, 2009 and 2019) and Group 2 ( n = 8, with data for 2009 and 2019). Data were analysed as the total annual number of cases and separately by anatomical region and patient demographics. A descriptive analysis was performed to characterize the trends. Results: Data from eight centres across Europe showed an increase in total annual arthroscopy cases (G1 from 53 to 202 and G2 from 393 to 615, p -value < 0.001) and as a percentage of paediatric orthopaedic surgeries (G1 from 1.6% to 5.2%; G2 from 5.1% to 6.8%) in seven out of eight centres. The knee remained the most commonly treated joint (G1 from 79.2% to 83.3%; G2 from 78.9% to 84.4%), despite the rise of others such as the elbow ( p -value = 0.020) and decline of the shoulder ( p -value = 0.014). Cases involving paediatric patients over 11 years increased while there was no gender distinction among paediatric patients. Conclusion: Paediatric arthroscopy procedures in Europe have increased in number over the past 3 decades. Technological advancements have allowed a surge in procedures and applications to new anatomical areas. Level of evidence: IV – retrospective database review.

The incidence of Anterior Cruciate Ligament (ACL) tears among pediatric patients has risen. Meniscal and cartilage damage are commonly associated with ACL injuries. Recognizing concurrent injuries during ACL surgery is essential to ensure an appropriate treatment. However, there is a lack of focus on children in Tanner stages 1 and 2. This study aims to describe associated lesions in Tanner 1-2 patients undergoing ACL surgical treatment and identify demographics, injury and surgical factors associated with their presence. This multicentric retrospective study involved 92 patients with Tanner 1-2 treated surgically for ACL injuries from 2002 to 2019. Data included demographic information, injury and surgerical details. Older age was associated with a significantly increased risk of concomitant lesions (p = 0.005). Meniscal tears were observed in 48.9% of patients. Lateral meniscal tears and posterior horn involvement were the most common pattern, neither ACL tear location or mechanism of injury influenced the occurrence of meniscal tears. Concomitant cartilage injuries were detected in 10.9% of patients. Tanner 1-2 patients with ACL tears have a high rate of associated lesions, particularly as age increases. These findings can help the surgical decision making and support the importance of a careful pre and intra-operative evaluation. III; retrospective study.

Background: Trochlear dysplasia is the primary anatomic risk factor for patellofemoral instability (PFI), but current classification systems rely on qualitative observations and are limited in their reproducibility. The Dejour Version 3.0 (2025) classification was established on quantitative magnetic resonance imaging (MRI)–based measurements in adults, but its validity in the pediatric population has yet to be evaluated. Purpose: To (1) assess the accuracy of the Dejour MRI-based classification of trochlear dysplasia in the diagnosis of PFI in children and adolescents and (2) derive pediatrics-specific thresholds of MRI-based measurements of dysplasia and additional risk factors to optimally predict PFI. Study Design: Case-control study; Level of evidence, 3. Methods: A total of 144 knees (127 patients) with objective PFI were age- and sex-matched to 144 controls. Four raters had excellent agreement on 7 measures of patellofemoral morphology: cartilaginous sulcus angle, lateral trochlear inclination, patellar tilt, lateral patellofemoral angle (LPFA), tibial tubercle–trochlear groove distance, sagittal central bump size, and Caton-Deschamps Index. Dejour Version 3.0 was assessed for sensitivity, specificity, and diagnostic accuracy, as defined by the area under the curve (AUC) for the respective receiver operating characteristic curves, within this study’s pediatric sample. Regression tree analysis with recursive partitioning was utilized to identify pediatrics-specific threshold values on MRI. Resulting combinations were assessed for their sensitivity, specificity, and diagnostic accuracy. The AUCs for the 2 options with the highest sensitivity were compared using a random forest (RF) model to evaluate optimal diagnostic accuracy. Results: Application of the 4 previously established adult cutoff combinations resulted in low/moderate sensitivity and fair/good diagnostic accuracy (range of AUCs, 0.79-0.87) in the study’s pediatric cohort. Regression tree analysis yielded 5 cutoff combinations, of which 2 achieved a sensitivity >90%. The first cutoff was a singular cartilaginous sulcus angle measurement ≥151° (sensitivity: 93% [95% CI, 87.6%-96.6%]; specificity: 87% [95% CI, 80.2%-91.9%]; AUC, 0.94); the second cutoff combination incorporated an LPFA cutoff <0.45° if the cartilaginous sulcus angle was <151° (sensitivity: 98% [95% CI, 94.0%-99.6%]; specificity: 85% [95% CI, 78.6%-90.7%]; AUC, 0.97). The AUC for the second cutoff combination was noninferior to the AUC (RF) by a prespecified ΔAUC of 0.03 ( P = .33). Conclusion: Application of the Dejour classification of trochlear dysplasia utilizing adult-specific thresholds yielded only moderate accuracy in the diagnosis of PFI in pediatric patients. The authors present an MRI-based classification system utilizing objective measurements of trochlear and patellofemoral morphology, emphasizing a 2-measurement combination of sulcus angle and LPFA that yielded excellent diagnostic accuracy. This new classification system is presented as a practical tool to objectively diagnose pediatric PFI in the clinical setting.

Background: Patella alta is a key anatomic risk factor for patellofemoral instability (PFI), especially among young athletes performing pivoting sports, as it reduces patellofemoral engagement during early knee flexion. The Caton-Deschamps index (CDI) is a commonly used radiographic measure of patella alta, but it does not provide information on patellofemoral engagement, which is relevant in PFI. Magnetic resonance imaging (MRI)-based indices, such as the patellotrochlear index (PTI) and sagittal patellofemoral engagement (SPE), have been proposed as more appropriate assessments of functional patella alta . Purpose: To (1) compare the performance of PTI and SPE in evaluating functional patella alta in pediatric PFI as determined by CDI; and (2) explore the relationship among indices. Study Design: Case-control study; Level of evidence, 4. Methods: We analyzed 252 participants: 126 patients with PFI and 126 age- and sex-matched controls. Radiographic and MRI-based measurements of CDI, PTI, and SPE were compared between groups. Correlations between indices and receiver operating characteristic (ROC) analyses were conducted, using the CDI as a reference standard. Results: The CDI was significantly higher in patients with PFI than controls (1.317 ± 0.215 vs 1.094 ± 0.171; P < .001), whereas PTI and SPE did not differ significantly. SPE values were lower in patients with patella alta (0.403 ± 0.156 vs 0.476 ± 0.169; P = .013). PTI and SPE were strongly correlated ( r = 0.898; P < .001), both demonstrating weak inverse correlations with CDI. When stratifying by patella alta, 40.5% of alta cases had an SPE of >0.45, and 97.3% had a PTI of >0.125. Univariable logistic regression demonstrated that SPE predicted patella alta (odds ratio = 0.263 [95% CI, 0.024-2.847]; P = .031). ROC analysis demonstrated poor discriminative ability of PTI and SPE for patella alta (area under the ROC curve [AUC], 0.534-0.594) and PFI (AUC, 0.461-0.488), while CDI strongly predicted PFI with sensitivity and specificity exceeding 73%. Conclusion: PTI and SPE demonstrated poorer discriminative ability for patella alta than CDI. However, MRI-based indices frequently indicated preserved patellofemoral engagement despite CDI-defined patella alta, underscoring their complementary role.