Background Abnormal tibiofemoral contact stress and aberrant kinematics may influence the progression of osteoarthritis in the ACL-deficient and the ACL-reconstructed knee. However, relationships between contact stress and kinematics following ACL reconstruction are poorly understood. Therefore, we posed the following research questions: (1) How do ACL deficiency and reconstruction affect kinematics of and contact stress in the tibiofemoral joint? (2) What kinematic differences are associated with abnormal contact stress following ACL reconstruction? Hypothesis/Purpose Center-center ACL reconstruction will not restore knee kinematics and contact stress. Correlations will exist between abnormal contact stress and aberrant kinematics following ACL reconstruction will exist. Study Design Controlled laboratory study Methods Clinical tests of anterior and rotational stability were simulated on eleven cadaveric knees using an industrial robot. Tests were conducted with the ACL intact, sectioned, and after single bundle ACL reconstruction using a quadrupled hamstring autograft with tunnels drilled through the center of the native footprints. Kinematics were recorded during the tests. Contact stress was continuously recorded from a stress transducer fixed to the tibial plateau and mean contact stress was calculated regionally. Results ACL deficiency resulted in increased mean contact stress in the posterior sectors of the medial and lateral compartments under anterior and rotational loads, respectively. Reconstruction reduced stress in these locations; however contact stress abnormalities remained. On average, kinematics were overconstrained following ACL reconstruction (≤1.8mm and ≤2.6° in all directions). However, combinations of overconstrained and underconstrained motions in ab/adduction and medial-lateral translation in response to combined moments, and axial rotation, anterior-posterior and medial-lateral translation in response to an anterior load were associated with abnormal mean contact stress. Conclusions ACL reconstruction reduces high stresses generated in the posterior compartment of the ACL-deficient knee. Abnormal contact stress following ACL reconstruction is related to multiplanar variations in knee kinematics. Clinical Relevance Clinical measures of multiplanar kinematics may help to better characterize the quality of ACL reconstruction. Such measures may help identify those at increased risk of long-term joint degeneration following this surgery.

Summary:A 22 year old male presented with symptoms of gastric outlet obstruction. Endoscopy showed a hypertrophic nodular lesion around the pyloric opening with pyloric stenosis. The endoscopic biopsy and histopathological examination revealed tuberculosis involving the stomach, an extremely rare lesion.

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Background: Current advanced imaging classification systems for osteochondritis dissecans (OCD) of the knee grade severity of disease by identifying certain lesion characteristics. The most widely used are the Hefti and Nelson systems. A novel classification presents a simpler 3-group approach to diagnose knee OCD by magnetic resonance imaging (MRI), compared with the Hefti (5-group) and Nelson (4-group) classifications. The purpose of this study was to compare the reliability of this novel classification with that of the more complex, established systemsan initial step in establishing validity and clinical utility. Methods: In total, 120 standardized knee MRIs of patients with established knee OCD were preselected to capture the spectrum of lesion types, with regard to both progression and location of the lesion. Each of the MRIs were independently classified by 2 readers into the novel, Hefti, and Nelson classification systems. A random sample was rereviewed by 1 rater 6 weeks after initial review. The inter-rater and intrarater agreements were evaluated by estimating Krippendorff α. Results: In total, 106 knees were classified by the novel, Hefti, and Nelson classification systems, as 14 of the knees lacked the necessary MRI sequences. There were no differences in interrater and intrarater agreement across classification systems. Krippendorff α for inter-rater agreement was 0.51 (95% confidence interval, 0.33-0.66) for the Hefti classification, 0.50 (0.34-0.64) for the Nelson classification, and 0.49 (0.32-0.65) for the novel classification. The intrarater agreement was 0.88 (0.75-0.97) for the Hefti classification, 0.94 (0.86-0.99) for the Nelson classification, and 0.98 (0.94-1.00) for the novel classification system. Conclusions: The novel classification for knee OCD demonstrated near-perfect intrarater agreement and moderate inter-rater agreement, consistent with the current, well-established classification systems. Pending a subsequent study on validity and clinical utility, this simpler classification system may offer an alternative, noninvasive diagnostic method to guide clinical treatment. Level of Evidence: Level IV.

Background: Previous reports of transphyseal drilling in anterior cruciate ligament (ACL) reconstruction have demonstrated good clinical outcomes without subjective changes in further skeletal development. The purpose of this study is to evaluate radiographic changes during continued growth following a transphyseal ACL reconstruction using an anteromedial femoral (AM) drilling technique in patients with >18 months of growth remaining. Methods: A review of consecutive adolescents who underwent a soft tissue transphyseal ACL reconstruction using an AM drilling technique was performed. Inclusion criteria was 18 months of growth remaining based on radiographic bone age and standing radiographs at least one year from the index procedure. Demographic, preoperative, and postoperative data, and follow-up three-foot standing lower extremity radiographs were reviewed. Radiographic data included femoral length, tibial length, total lower extremity length, mechanical axis deviation (MAD), lateral distal femoral angle (LDFA), and medial proximal tibial angle (MPTA). Results: In total 12 adolescent patients with a mean age of 13.4 years (range, 12.3 to 14.4) and bone age of 13.4 years (11.5 to 14) at the time of surgery were included. At an average of 2.27-year follow-up (412 to 1058 d), there was no difference in the total growth of the operative and nonoperative limb (48.5 mm vs. 47 mm; P=0.36). In addition, the average increases in femoral length (23.4 mm) and tibial length (25.8 mm) were not statistically different between the operative and the nonoperative limb (P=0.12; P=0.75). There was no statistical difference in mechanical axis deviation, LDFA, or MPTA between preoperative and postoperative radiographs. Mean differences in operative and nonoperative coronal angular changes were all <1.5 degrees. Conclusions: With at least 2 years of growth remaining, transphyseal ACL reconstruction with anteromedial drilling did not significantly affect the physis or residual growth compared with the contralateral extremity. Although this technique may create a larger defect in the physis, standing radiographs demonstrate there is no change in limb length or angulation in growing adolescents approximately 2 years after surgery. Level of Evidence: This is a case series; Level IV evidence.