Participation in marathons has increased without any change in mortality or average overall performance from 2000 to 2009.

Background: Impaction fractures of the posterolateral tibial plateau commonly occur in the setting of anterior cruciate ligament (ACL) tears, with considerable variability found in fracture size and morphologic features. Purpose: The primary objective was to characterize different morphologic variants of posterolateral tibial plateau impaction fractures. The secondary objective was to investigate the association between these impaction fracture variants and concomitant meniscal and ligamentous injuries. Study Design: Cross-sectional study; Level of evidence 3. Methods: Patients treated for primary ACL tears and having magnetic resonance imaging available were included in this study, and magnetic resonance images were reviewed with denotation of displaced posterolateral tibial impaction fractures. A classification system was created based on morphologic variants of impaction fractures; associations were evaluated through use of independent chi-square testing. Results: There were 825 knees meeting the inclusion criteria, with displaced posterolateral tibial plateau impaction fractures present in 407 knees (49.3%). We observed 3 distinct morphologic variants of lateral tibial plateau impaction fractures: (I) posterior cortical buckle not involving the articular surface; (II) posterior impaction fracture involving the articular surface, with subtypes based on (A) tibial plateau depth bone loss <10% and (B) bone loss >10%; and (III) displaced osteochondral fragment, with subtypes for (A) shear or (B) depressed fragment. Type IIIA impaction fractures were associated with an increased incidence of lateral meniscus posterior root tears (33.3% vs 12.4%; P = .009) and an increased incidence of lateral meniscal tears (83.3% vs 56.7%; P = .024) compared with all knees without type IIIA impaction fracture. An increased incidence of medial collateral ligament (MCL) tears was noted in patients with type IIIA impaction fractures compared with those who had no fracture or had another fracture type (61.1% vs 20.1%; P < .001). Type IIIB impaction fractures were associated with an increased incidence of lateral meniscal tears (80.0% vs 56.2%; P = .005). Conclusion: A high prevalence of displaced posterolateral tibial plateau impaction fractures occur in the setting of ACL tears, and they can be classified into distinct morphologic subtypes. Posterolateral tibial plateau impaction fractures with displaced depressed or shear fragments were both associated with an increased incidence of lateral meniscal tears, whereas impaction fractures with a shear fragment were associated with an increased incidence of lateral meniscus posterior root tears and MCL tears.

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Background: Bone bruising of the posterolateral tibial plateau and the lateral femoral condyle sulcus terminalis has a well-established association with anterior cruciate ligament (ACL) tears. Impaction fractures of the femur and tibia may occur in these locations; however, there is a paucity of literature describing these fractures. Purpose: The primary objective was to quantify the incidence, size, and location of impaction fractures of the posterolateral tibial plateau and lateral femoral condyle in patients with primary ACL tears. The secondary objective was to investigate the association between impaction fractures and concomitant meniscal and ligamentous injuries. Study Design: Case series; Level of evidence 4. Methods: Patients with available magnetic resonance imaging (MRI) scans who were treated for primary ACL tear by a single surgeon were identified. MRI scans were reviewed with denotation of posterolateral tibial and femoral condylar contusions and displaced impaction fractures. Measurements of the lateral tibial plateau were taken in all patients with displaced lateral tibial plateau fractures and in a subset of control patients without tibial plateau fracture present to characterize the size and location of the bony lesion. Associations of impaction fractures with concomitant meniscal or ligamentous injuries were evaluated through use of chi-square testing. Results: There were 825 knees identified with available MRI scans. Lateral tibial plateau bone bruising was present in 634 knees (76.8%), and lateral femoral condyle bone bruising was present in 407 knees (49.3%). Posterolateral tibial plateau impaction fractures were present in 407 knees (49.3%), and lateral femoral condylar impaction fractures were present in 214 knees (25.9%). Patients with posterolateral tibial plateau impaction fractures were older than patients without these fractures (42.6 vs 32.7 years; P < .001), whereas patients with lateral femoral condylar impaction fractures were younger (23.8 vs 32.7 years; P < .001). There were 71 knees (8.6%) with a posterolateral tibial plateau impaction fracture with greater than 10% loss of lateral tibial plateau depth, and this group had an increased incidence of lateral meniscus posterior root tears (22.1% vs 12.0%; P = .02). Conclusion: Posterolateral tibial plateau impaction fractures occurred with a high incidence (49.3%) in patients with primary ACL tears and demonstrated an increased association with lateral meniscus posterior horn root tears as their size increased. Lateral femoral condylar impaction fractures occurred in 25.9% of patients with primary ACL tears and entailed an increased incidence of lateral meniscal tears and medial meniscal ramp lesions.

Background: The ulnar collateral ligament (UCL) microstructural organization and collagen fiber realignment in response to load are unknown. Purpose/Hypothesis: The purpose was to describe the real-time microstructural collagen changes in the anterior bundle (AB) and posterior bundle (PB) of the UCL with tensile load. It was hypothesized that the UCL AB is stronger and stiffer with more highly aligned collagen during loading when compared with the UCL PB. Study Design: Descriptive laboratory study. Methods: The AB and PB from 34 fresh cadaveric specimens were longitudinally sectioned to allow uniform light passage for quantitative polarized light imaging. Specimens were secured to a tensile test machine and underwent cyclic preconditioning, a ramp-and-hold stress-relaxation test, and a quasi-static ramp to failure. A division-of-focal-plane polarization camera captured real-time pixelwise microstructural data of each sample during stress-relaxation and at the zero, transition, and linear points of the stress-strain curve. The SD of the angle of polarization determined the deviation of the average direction of collagen fibers in the tissue, while the average degree of linear polarization evaluated the strength of collagen alignment in those directions. Since the data were nonnormally distributed, the median 6 interquartile range are presented. Results: The AB has larger elastic moduli than the PB (P \ .0001) in the toe region (median, 2.73 MPa [interquartile range, 1.1-5.6 MPa] vs 0.65 MPa [0.44-1.5 MPa]) and the linear region (13.77 MPa [4.8-40.7 MPa] vs 1.96 MPa [0.58-9.3 MPa]). The AB demonstrated larger stress values, stronger collagen alignment, and more uniform collagen organization during stress-relaxation. PB collagen fibers were more disorganized than the AB during the zero (P = .046), transitional (P = .011), and linear (P = .007) regions of the stress-strain curve. Both UCL bundles exhibited very small changes in collagen alignment (SD of the angle of polarization) with load. Conclusion: The AB of the UCL is stiffer and stronger, with more strongly aligned and more uniformly oriented collagen fibers, than the PB. The small changes in collagen alignment indicate that the UCL response to load is due more to its static collagen organization than to dynamic changes in collagen alignment. Clinical Relevance: The UCL collagen organization may explain its susceptibility to injury with repetitive valgus loads.

Fractures of the anteroinferior aspect of the glenoid rim, known as a bony Bankart lesions, can occur frequently in the setting of traumatic anterior shoulder dislocation. If these lesions are large and are left untreated in active patients, then recurrent glenohumeral instability due to glenoid bone deficiency may occur. Therefore, the clinician must recognize these lesions when they occur and provide appropriate treatment to restore physiological joint stability. This article aims to provide an overview focusing on clinical and technical considerations in the diagnosis and treatment of bony Bankart lesions.

Background: Impaction fractures of the posterolateral tibial plateau have been previously described to occur in association with anterior cruciate ligament (ACL) tears; however, the effect of these injuries on patient-reported outcomes (PROs) after ACL reconstruction (ACLR) is not well known. Purpose: (1) To assess the effect of posterolateral tibial plateau impaction fractures on preoperative clinical knee stability assessed by the Lachman and pivot-shift examinations and (2) to assess the effect of impaction fractures on PROs after ACLR. Study Design: Cohort study; Level of evidence, 3. Methods: Patients undergoing ACLR for primary ACL tears with available magnetic resonance imaging (MRI) scans were included in this study. MRI scans were reviewed for the presence of posterolateral tibial plateau impaction fractures, which were classified according to the morphological variant. Associations with clinical laxity determined by an examination under anesthesia were assessed using binary logistic regression. Also, 2-year postoperative PROs (12-Item Short Form Health Survey [SF-12] Mental Component Scale and Physical Component Scale [PCS], Lysholm, Western Ontario and McMaster Universities Osteoarthritis Index [WOMAC], and Tegner scores) were modeled using multiple ordinal logistic regression to assess the effect of posterolateral tibial plateau impaction fracture classification while adjusting for other covariates. Pearson correlation coefficients (PCCs) were used to assess for correlations between postoperative PROs and the amount of tibial plateau bone loss present. Results: Displaced posterolateral tibial plateau impaction fractures were present in 407 (49.3%) of 825 total knees included in this study. Knees with type IIIB impaction fractures had an increased likelihood of having a high-grade pivot shift (odds ratio, 2.3; P = .047), with no other impaction fracture types showing a significant association. There were no significant associations between posterolateral tibial plateau impaction fracture type and a higher Lachman grade. Of the 599 eligible knees with 2-year follow-up, postoperative information was obtained for 419 (70.0%). Patients improved in all PROs at a mean of 3.0 years after ACLR ( P < .001). Multiple ordinal logistic regression demonstrated a posterolateral tibial plateau impaction fracture as an independent predictor of the postoperative Lysholm score, with higher grade impaction fractures showing decreased Lysholm scores. Pearson correlation testing demonstrated weak but statistically significant correlations between sagittal bone loss of posterolateral tibial plateau impaction fractures and SF-12 PCS (PCC = –0.156; P = .023), WOMAC total (PCC = 0.159; P = .02), Lysholm (PCC = –0.203; P = .003), and Tegner scores (PCC = –0.151; P = .032). Conclusion: When classified into distinct morphological subtypes, high-grade posterolateral tibial plateau impaction fractures were independently associated with decreased postoperative outcomes after ACLR when controlling for other demographic or clinical variables. Patients with large depression-type posterolateral tibial plateau impaction fractures (type IIIB) had an increased likelihood of having high-grade pivot-shift laxity on clinical examination under anesthesia.

Purpose While the association with acute anterior cruciate ligament (ACL) tears has been established, other risk factors and associated pathologies which occur with a concomitant lateral meniscal posterior root tear (LMPRT) are not well deined. The purpose of this study was to compare the risk factors and concomitant pathologies between patients with LMPRT and patients without LMPRTs in the setting of a primary ACL tear. Methods Patients with a LMPRT identiied at the time of primary ACL reconstruction by a single surgeon were identiied. These patients were matched by age and sex to patients undergoing primary ACL reconstruction who were not found to have lateral meniscus root tears (control group) in a 1:1 ratio. Lateral posterior tibial slope (PTS), medial PTS, lateral femoral condyle height and depth, lateral tibial plateau depth, and lateral tibial plateau subluxation were measured on MRI. Anteroposterior full-limb alignment radiographs were used to measure the medial proximal tibia angle (MPTA), the mechanical lateral distal femoral angle (mLDFA), and the mechanical weightbearing axis for the injured extremity. Results One-hundred three patients were included in both the LMPRT group and the matched control group. Patients with a LMPRT had a signiicantly steeper lateral PTS (9.1° vs. 7.0°, p = 0.001), a steeper medial PTS (7.0° vs. 6.0°, p = 0.03), and a greater lateral-to-medial slope asymmetry (2.0° vs. 1.0°, p = 0.001). There were no diferences in lateral femoral condyle depth or height, lateral tibial plateau depth, lateral tibial plateau subluxation, MPTA, mLDFA, or mechanical weightbearing axis between groups. There was a signiicantly increased incidence of medial meniscus ramp lesions in patients with lateral meniscus posterior root tears compared with controls (34.0% vs. 15.5%, odds ratio: 2.8, p = 0.002). There were no associations with concomitant ligament injuries, medial meniscus root tears, or non-ramp tears based on case/control grouping. ConclusionIn conclusion, LMPRTs in the setting of primary ACL injuries were associated with signiicantly increased lateral and medial PTSs, and increased asymmetry between lateral and medial PTSs. In addition, clinicians should be aware of the increased incidence of concurrent medial meniscal ramp lesions in patients with LMPRTs. Knowledge of these associations helps guide clinical decision-making and counselling of patients in the setting of ACL tears with concomitant LMPRTs. Level of evidence IV.