Changes in tissue sodium concentration and sodium relaxation times during the maturation of human knee cartilage: Ex vivo 23 Na MRI study at 10.5 T.

PURPOSE: To evaluate the influence of skeletal maturation on sodium (23 Na) MRI relaxation parameters and the accuracy of tissue sodium concentration (TSC) quantification in human knee cartilage. METHODS: Twelve pediatric knee specimens were imaged with whole-body 10.5 T MRI using a density-adapted 3D radial projection sequence to evaluate 23 Na parameters: B1 + , T1 , biexponential T 2 * $$ {\mathrm{T}}_2^{\ast } $$ , and TSC. Water, collagen, and sulfated glycosaminoglycan (sGAG) content were calculated from osteochondral biopsies. The TSC was corrected for B1 + , relaxation, and water content. The literature-based TSC (TSCLB ) used previously published values for corrections, whereas the specimen-specific TSC (TSCSP ) used measurements from individual specimens. 23 Na parameters were evaluated in eight cartilage compartments segmented on proton images. Associations between 23 Na parameters, TSCLB - TSCSP difference, biochemical content, and age were determined. RESULTS: From birth to 12 years, cartilage water content decreased by 18%; collagen increased by 59%; and sGAG decreased by 36% (all R2 ≥ 0.557). The short T 2 * $$ {\mathrm{T}}_2^{\ast } $$ ( T 2 * S $$ {{\mathrm{T}}_2^{\ast}}_{\mathrm{S}} $$ ) decreased by 72%, and the signal fraction relaxing with T 2 * S $$ {{\mathrm{T}}_2^{\ast}}_{\mathrm{S}} $$ ( fT 2 * S $$ {{\mathrm{fT}}_2^{\ast}}_{\mathrm{S}} $$ ) increased by 55% during the first 5 years but remained relatively stable after that. TSCSP was significantly correlated with sGAG content from biopsies (R2 = 0.739). Depending on age, TSCLB showed higher or lower values than TSCSP . The TSCLB - TSCSP difference was significantly correlated with T 2 * S $$ {{\mathrm{T}}_2^{\ast}}_{\mathrm{S}} $$ (R2 = 0.850), fT 2 * S $$ {{\mathrm{fT}}_2^{\ast}}_{\mathrm{S}} $$ (R2 = 0.651), and water content (R2 = 0.738). CONCLUSION: TSC and relaxation parameters measured with 23 Na MRI provide noninvasive information about changes in sGAG content and collagen matrix during cartilage maturation. Cartilage TSC quantification assuming fixed relaxation may be feasible in children older than 5 years.

Tibial derotational osteotomy for idiopathic tibial torsion: A systematic review of surgical indications based on clinical presentation and measurement technique.

PURPOSE: The aim of this systematic review was to identify the surgical indications of tibial derotational osteotomy (TDO) in patients with idiopathic external tibial torsion (ETT) and identify common measurement thresholds for surgical correction. METHODS: A systematic search of MEDLINE and Embase via Ovid, Cochrane Library via Wiley, Web of Science, Scopus, SPORTDiscus via EBSCOhost, ClinicalTrials.gov, WHO ICTRP and Global Index Medicus databases was performed with search terms reflecting the concepts of idiopathic tibial torsion, TDOs, and surgical indications. Studies reporting surgical indications and measurement methods of idiopathic tibial torsion in patients who underwent TDO were included. Two authors independently screened articles and extracted data that was characterized with descriptive statistics. RESULTS: Seventeen studies were identified for inclusion, with 460 tibias and 351 patients. Nearly all patients who underwent surgery had either anterior knee pain or patellar instability, even if other indications were present. Of all included patients, the most common surgical indications for TDO were anterior knee pain (88%), patellar instability (59%), gait dysfunction (41%) and cosmetic deformity (12%). Twelve studies (71%) cited multiple of these indications as reasons for surgery. On physical exam, tibial torsion was measured most commonly by thigh-foot angle (59%) (TFA) and transmalleolar axis (24%) (TMA). In terms of TFA, the most frequently reported cut-off for ETT was >30° (35%). Computerized tomography (CT) was used by nine studies (53%). The most common CT axes used to measure ETT were the TMA with respect to the posterior tibia condylar axis or the bicondylar tibia axis. CONCLUSION: Anterior knee pain and/or patellar instability are common indications for TDO in patients with idiopathic tibial torsion. Standardized TFA thresholds (>30°) and CT measurement methods (TMA and posterior tibia condylar or bicondylar tibial axis) may help further establish objective surgical indications. LEVEL OF EVIDENCE: IV.

Improved Patient-reported Outcomes in Patients Aged 16 and Younger at Two Years After Anterior Cruciate Ligament Reconstruction Despite Relatively High Rates of Reinjury and Repeat Surgery.

BACKGROUND: Anterior cruciate ligament reconstruction (ACLR) in adolescent patients, particularly those aged 16 and under, are increasingly common procedure that lacks robust clinical and patient-reported outcome (PRO) data. The purpose of this study was to report 2-year PROs of patients receiving ACLR aged 16 or younger using the single assessment numerical evaluation (SANE) and knee injury and osteoarthritis outcome score (KOOS). Secondary aims included characterizing treatment characteristics, return to sport (RTS), and clinical outcomes. METHODS: The institutional PRO database was queried for patients receiving ACLR from 2009 to 2020. Patients aged older than 16, revision procedures, concomitant ligament repairs/reconstructions, and patients without full outcome data at 2 years were excluded. Outcomes over 2 years after ACLR included SANE, KOOS, reinjuries, reoperations, and time to RTS. RESULTS: A total of 98 patients were included with an average age of 15.0 years. Most patients were females (77.6%). Bone-tendon-bone autograft (69.4%) was the most used. Average RTS was 8.7 months (range: 4.8 to 24.0 mo), with 90% of patients eventually returning to sport. A total of 23 patients (23.5%) experienced a reinjury and 24.5% (n = 24) underwent reoperation. Timing to RTS was not associated with reinjury, but patients who returned between 9.5 and 13.7 months did not sustain reinjuries. Mean KOOS and SANE scores at 2 years were 87.1 and 89.1, respectively, with an average improvement of +18.4 and +22.9, respectively. Change in KOOS was negatively impacted by reinjury to the anterior cruciate ligament graft and reoperation (anterior cruciate ligament failure: +10.0 vs 19.3, P = 0.081, respectively; reoperation: +13.2 vs +20.1, P = 0.051, respectively), though these did not reach statistical significance. CONCLUSION: Patients experienced improved SANE and KOOS scores after ACLR. Rates of reinjury and reoperation were relatively high and negatively impacted PRO scores but were not associated with the timing of RTS. Adolescent patients should be counseled regarding the risk of subsequent ipsilateral and contralateral knee injury after ACLR. LEVEL OF EVIDENCE: Level IV-case series.

Rising incidence of stair-related upper extremity fractures among older adults in the United States: a 10-year nationwide analysis.

Upper extremity (UE) fractures are prevalent age-related fractures, and stair-associated falls are a common mechanism for these injuries. Our study has identified an increasing incidence of stair-related UE fractures and associated hospitalization rates among the older United States population between 2012-2021. Targeted prevention efforts should be implemented by health systems. INTRODUCTION: To analyze United States (US) emergency department trends in upper extremity stair-related fractures among older adults and investigate risk factors associated with hospitalization. METHODS: We queried the National Electronic Injury Surveillance System (NEISS) for all stair-related fracture injuries between 2012 and 2021 among adults 65 years or older. The US Census Bureau International Database (IDB) was analyzed to calculate incidence rates. Descriptive analysis, linear regression analysis, and multivariate regression analysis were used to interpret the collected data. RESULTS: Our analysis estimated 251,041 (95% CI: 211,678-290,404) upper extremity stair-related fractures among older adults occurred between 2012 and 2021. The primary anatomical locations were the humeral shaft (27%), wrist (26%), and proximal humerus (18%). We found a 56% increase in injuries (R2 = 0.77, p < 0.001), 7% increase in incidence per 100,000 persons (R2 = 0.42, p < 0.05), and an 38% increase in hospitalization rate (R2 = 0.61, p < 0.01) during the 10-year study period. Women sustained the majority of fractures (76%) and most injuries occurred in homes (89%). Advanced age (p < 0.0001), males (p < 0.0001), proximal humerus fractures (p < 0.0001), humeral shaft fractures (p < 0.0001), and elbow fractures (p < 0.0001) were associated with increased odds of hospitalization after injury. CONCLUSION: Stair-related UE fracture injuries, incidence, and hospitalization rates among older adults are increasing significantly, particularly among older females. Improving bone health, optimizing functional muscle mass, and "fall-proofing" homes of older age groups may help mitigate the rising incidence of these injuries.

Sofa and bed-related pediatric trauma injuries treated in United States emergency departments.

INTRODUCTION: Children under the age of 5 years suffer from the highest rates of fall-related injuries. Caretakers often leave young children on sofas and beds, however, falling and rolling off these fixtures can lead to serious injury. We investigated the epidemiologic characteristics and trends of bed and sofa-related injuries among children aged <5 years treated in US emergency departments (EDs). METHODS: We conducted a retrospective analysis of data from the National Electronic Injury Surveillance System from 2007 through 2021 using sample weights to estimate national numbers and rates of bed and sofa-related injuries. Descriptive statistics and regression analyses were employed. RESULTS: An estimated 3,414,007 children aged <5 years were treated for bed and sofa-related injuries in emergency departments (EDs) in the United States from 2007 through 2021, averaging 115.2 injuries per 10,000 persons annually. Closed head injuries (30%) and lacerations (24%) comprised the majority of injuries. The primary location of injury was the head (71%) and upper extremity (17%). Children <1 year of age accounted for most injuries, with a 67% increase in incidence within the age group between 2007 and 2021 (p < 0.001). Falling, jumping, and rolling off beds and sofas were the primary mechanisms of injury. The proportion of jumping injuries increased with age. Approximately 4% of all injuries required hospitalization. Children <1 year of age were 1.58 times more likely to be hospitalized after injury than all other age groups (p < 0.001). CONCLUSION: Beds and sofas can be associated with injury among young children, especially infants. The annual rate of bed and sofa-related injuries among infants <1 year old is increasing, which underscores the need for increased prevention efforts, including parental education and improved safety design, to decrease these injuries.

An MCL internal brace can withstand cyclic fatigue loading and produce a valgus load to failure similar to that of intact knees.

PURPOSE: The purpose of this study is to report on the biomechanical durability and strength of an MCL internal brace construct. The null hypothesis is that there will be no difference between this construct and the intact MCL in terms of deflection during fatigue testing and the ultimate failure load. METHODS: Eight cadaver knees were used. A grade 3 equivalent MCL tear was created with both the superficial and deep femoral MCL severed. An internal brace was created by placing a cortical button and loop through the center of the femoral MCL origin and secured on the lateral cortex of the distal femur. A FiberTape (Arthrex, Naples, FL) was looped through the cortical button loop and was secured in the center of the tibial insertion of the MCL. After pre-cycling, the specimens underwent 1000 cycles of compressive load between 100 and 300 N, using four point bending testing into direct valgus. Pre and post testing deflection was measured using three dimensional motion data from two sets of reflective markers. A load-to-failure test was then conducted with failure defined as the first significant decrease in the load-displacement curve. RESULTS: The mean increase in deflection between pre- and post-testing was 0.6° (SD ± 0.3°). The mean failure bending moment was 122.4 Nm (SD ± 29 Nm). CONCLUSION: The internal brace construct employed in this study was able to withstand cyclic fatigue loading and recorded a valgus load to failure similar to that of intact knees. It is important for clinicians who are considering using this commercially available technique to be aware of how the construct performs under cyclic loading compared to the intact MCL.

MCL internal brace does not fully recapitulate normal MCL function in valgus stress.

PURPOSE: The null hypothesis is that there would be no difference in medial gapping under valgus load between the intact MCL and the ruptured MCL with an internal brace in place. METHODS: Eight pairs of cadaver knees were used (16 knees). Alternating sides, one knee from each pair was used for one of two "internal brace" constructs. The constructs involved different methods of fixation for securing FiberTape (Arthrex, Naples, FL) to both the femur and tibia in an effort to brace the MCL. The knees were then subjected to valgus stress by applying 10 N m of torque with the knee at 20 degrees of flexion. The amount of medial joint space opening was measured on radiographs. The stress testing was conducted with three MCL states: intact, grade 2 tear, and grade 3 tear. RESULTS: In the Construct I specimens, gapping increased from 0.7 mm with the MCL intact to 1.1 mm with grade 2 tearing (p < 0.01), and to 1.3 mm with grade 3 tearing (p < 0.01). In the Construct II specimens, gapping increased from 0.7 mm with the MCL intact to 1.0 mm with grade 2 tearing (p < 0.01), and to 1.1 mm with grade 3 tearing (n.s.). Construct I specimens failed primarily at the femoral attachment. All Construct II specimens survived the valgus stress testing. CONCLUSION: Construct I did not maintain tension. Construct II did maintain tension during application of valgus load, but did not restore valgus opening to the intact state. It is important for clinicians who are considering using this commercially available technique to be aware of how the construct performs under valgus stress testing compared to the intact MCL.

Pediatric meniscus morphology varies with age: a cadaveric study.

PURPOSE: In adolescent patients, meniscal tear injury can occur either in isolation (e.g., discoid lateral meniscus tears) or in association with other traumatic injuries including tibial eminence fracture or ACL tear. Damage to meniscal integrity has been shown to increase contact pressure in articular cartilage, increasing risk of early onset osteoarthritis. In symptomatic patients failing conservative management, surgical intervention via meniscus repair or meniscus transplant is indicated. The purpose of this study was to evaluate the radial dimensions of pediatric menisci throughout development. The hypothesis was that the average radial meniscus dimensions will increase as specimen age increases, and mean medial and lateral region measurements will increase at a linear rate. METHODS: Seventy-eight skeletally immature knee cadaver specimens under age 12 years were included in this study. The meniscal specimens were photographed in the axial view with ruler in the plane of the tibial plateau and analyzed using computer-aided design (CAD) software (Autodesk Fusion 360). Measurements were taken from inner to outer meniscus rims at five 45 degree intervals using the clockface as a reference (12:00, 1:30, 3:00, 4:30, 6:00), and total area of meniscus and tibial plateau was recorded. Generalized linear models were used to evaluate the associations of radial width measurements with age, tibial coverage, and lateral vs. medial meniscus widths. RESULTS: All radial width measurements increased significantly with specimen age (p ≤ 0.002), and all lateral-medial meniscal widths increased (p < 0.001). The anterior zones of the meniscus were found to increase at the slowest rate compared to other regions. Tibial plateau coverage was found to not significantly vary with age. CONCLUSIONS: Meniscus radial width and lateral-medial meniscus width are related to age. The anterior width of the meniscus varied least with age. Improved anatomic understanding may help surgeons more effectively plan for meniscus repair, discoid resection/saucerization/repair, and also support appropriate selection of meniscus allograft for transplantation.

American Shoulder and Elbow Surgeons SLAP/Biceps Anchor Study Group evidence review: pathoanatomy and diagnosis in clinically significant labral injuries.

Glenoid superior biceps-labral pathology diagnosis, treatment, and outcomes are an evolving area of shoulder surgery. Historically, described as superior labrum anterior posterior (SLAP) tears, these lesions were identified as a source of pain in throwing athletes. Diagnosis and treatments applied to these SLAP lesions resulted in less than optimal outcomes in some patients and a prevailing sense of confusion. The purpose of this paper is to perform a reappraisal of the anatomy, examination, imaging, and diagnosis by the American Shoulder and Elbow Surgeons/SLAP biceps study group. We sought to capture emerging concepts and suggest a more unified approach to evaluation and identify specific needs for future research.

A new device for patellofemoral instrumented stress-testing provides good reliability and validity.

PURPOSE: To evaluate the reliability of an instrumented patellofemoral (PF) stress-testing-the Porto Patellofemoral Testing Device (PPTD)-and validate the instrumented assessment method comparing to manual physical examination. METHODS: Eight asymptomatic volunteers underwent bilateral PF-instrumented examination with the PPTD and magnetic resonance imaging (MRI) to assess intra-rater reliability of the instrumented assessment methodology. Six patients with unilateral PF instability underwent physical examination and PPTD concomitantly with MRI. Manual examination was performed by two blinded surgeons and compared with PPTD test. Ligament stiffness was calculated and compared between injured and non-injured lower limbs. RESULTS: PPTD showed a pre-determined and reproducible stress-force application with excellent intra-rater agreement (intra-class correlation coefficient 0.83-0.98). The manual exam was imprecise with variable examiner-dependent stress-force application. The PPTD resulted in greater lateral patellar translation (converted in quadrants) than manual exam for patients that have reached maximum translation force. Measurement of patellar position and displacement using PPTD was more accurate and precise than the visual estimation of translated quadrants by manual exam. Ligament stiffness curves showed no relevant changes in patellar displacement after 62 N. CONCLUSION: The PPTD instrumented stress-testing is a valid device to quantify PF position and displacement with high intra-rater reliability, showing more accuracy, more precision and less variability than physical examination. This device provides an accurate and objective measure to quantify the patellar movement which can augment the physical examination procedures and assist clinicians in the management of decision-making and in the assessment of post-treatment outcomes of PF pathological conditions.

Patellar-Trochlear Morphology in Pediatric Patients From 2 to 11 Years of Age: A Descriptive Analysis Based on Computed Tomography Scanning.

BACKGROUND: Despite the critical role the trochlea plays in patellofemoral (PF) pathology, the development of the trochlea is poorly understood. The purpose of this study was 2-fold: (1) Describe quantitative osseous and soft tissue anatomy of the patella and trochlea in skeletally immature cadaveric specimens utilizing known measurements used in PF instability, and (2) evaluate additional measurement techniques in the sagittal plane as they relate to PF morphologic development. METHODS: Thirty-one skeletally immature fresh frozen cadaveric knees between the ages of 2 and 11 years old were evaluated using 0.625 mm computed tomography scans. In the axial plane, measurements included condylar height asymmetry, trochlear facet asymmetry, trochlear depth, osseous sulcus angle, cartilaginous sulcus angle, patella sulcus angle, and tibial tubercle-trochlear groove distance. In the sagittal plane, measurements included previously undescribed measurements of trochlear length and condylar height asymmetry which are based on the anterior femoral cortex. RESULTS: Analysis of trochlear morphology using condylar height asymmetry (both axial and sagittal), trochlear facet asymmetry, and trochlear depth and length demonstrated an increase in the size of the medial and lateral trochlea as age increased. There was more variability in the change of size of the medial trochlea (height, length, and facet length) than the lateral trochlea. The osseous sulcus angle, cartilaginous sulcus angle, and patella sulcus angle decreased (became deeper) with age until after 8 years and then plateaued. CONCLUSIONS: This cadaveric analysis demonstrated that there is an increase in the medial and lateral trochlear height as age increased by all measurements analyzed. The findings also demonstrate that the shape of the patella and trochlea change concurrently, which suggests that there may be interplay between the 2 during development. These new sagittal measurement techniques evaluating the medial, central, and lateral trochlear height and length with respect to age may help guide clinicians when investigating patellar instability in skeletally immature patients. LEVELS OF EVIDENCE: Level IV.

Radiographic Landmarks for the Anterior Attachment of the Medial Patellofemoral Complex.

PURPOSE: Because fluoroscopy is often used in graft placement during patellar stabilization surgery, the purpose of this study was to describe the radiographic landmarks for the anterior attachment midpoint of the medial patellofemoral complex (MPFC). METHODS: Seventeen fresh-frozen cadaveric knees were dissected, and the MPFC was exposed from the articular side after a lateral parapatellar approach. The midpoint of the anterior attachment of the MPFC was identified using a ruler and marked with a pin. Lateral fluoroscopic images of the patella were then obtained and analyzed using digital analysis software. The distance from the superior articular pole to the pin was divided by the length of the articular surface to describe the location of the pin as a percentage of patellar articular length. RESULTS: Of the 17 cadaveric knees, 2 were excluded because of lack of MPFC fibers. In the remaining 15 knees, the mean (±standard deviation) proximal-distal width of the attachment to the patella and/or vastus intermedius tendon was 41 ± 10 mm, spanning from 15 ± 6 mm proximal to the superior pole of the patella to 27 ± 8 mm distal to it. When viewed on lateral fluoroscopic images, the MPFC midpoint was 19% ± 14% of the patellar articular length from the superior articular pole. CONCLUSIONS: In this study, the radiographic landmarks that correlate to the anatomic midpoint of the anterior MPFC attachment are 19% ± 14% of the articular surface from the superior pole of the patella. CLINICAL RELEVANCE: Recent reports on medial patellofemoral ligament anatomy now include fibers that extend to the quadriceps tendon, summarized as the MPFC. With the inclusion of these fibers, the midpoint of the anterior MPFC attachment is more proximal than that of the medial patellofemoral ligament alone. Because fluoroscopy is often used intraoperatively to guide graft placement, this study correlates radiographic landmarks with anatomic findings of the MPFC midpoint on its attachment to the extensor mechanism.

Editorial Commentary: Similar Outcomes Among Surgical Techniques for Unstable Acromioclavicular Injuries: Is There More to the Story?

There are many ways to perform stabilization of unstable acromioclavicular injuries, and there are generally good results with all surgical techniques. Unfortunately, the literature is weak on comparing surgical results with nonsurgical management, so we still have not defined which patients need surgery and which patients do not.

Q-vector measurements: physical examination versus magnetic resonance imaging measurements and their relationship with tibial tubercle-trochlear groove distance.

PURPOSE: An increased lateral quadriceps vector has been associated with lateral patellar dislocation. Surgical correction of this increased vector through tibial tubercle medialization is often recommended when the quadriceps vector is "excessive". This can be evaluated by physical examination measurements of Q-angle and/or tubercle sulcus angle (TSA), as well as the magnetic resonance imaging (MRI) measurement of tibial tubercle-trochlear groove (TT-TG) distance. This study examined the relationship between three objective measurements of lateral quadriceps vector (TT-TG, Q-angle, TSA). A secondary goal was to relate lateral patellar tilt to these measurements. METHODS: Consecutive patients undergoing patellofemoral stabilization surgery from 9/2010 to 6/2011 were included. The Q-angle and TSA were measured on intra-operative physical examination. The TT-TG and patellar tilt were measured on MRI. TSA, Q-angle, and patellar tilt were compared to TT-TG using Pearson correlation coefficient. RESULTS: The study cohort included 49 patients, ages 12-37 (mean 23.2); 62% female. The Pearson correlation coefficients showed (+) significance (p < 0.01) between the TT-TG and both TSA and Q-angle. Tilt and TT-TG were (+) non-significantly correlated. Despite positive correlations of each measurement with TT-TG, there is not uniform intra-patient correlation. In other words, if TT-TG is elevated for a patient, it does not guarantee that all other measurements, including tilt, are elevated in that individual patient. CONCLUSION: The TT-TG distance has significant positive correlation with the measurements of TSA and Q-angle in patients undergoing surgery for patellofemoral instability. The clinical relevance is that the variability within individual patients demonstrates the need for considering both TSA and TT-TG before and during surgical intervention to avoid overcorrection with a medial tibial tubercle osteotomy. LEVEL OF EVIDENCE: Diagnostic study, Level III.

Anatomic patellar instability risk factors in primary lateral patellar dislocations do not predict injury patterns: an MRI-based study.

PURPOSE: The primary goal was to describe the injury patterns in a population of primary (first time) lateral patellar dislocators (LPD) to lend clarity to commonly held notions about injury patterns in this population. METHODS: A prospective study identifying patients presenting with LPD between 2008 and 2012. Inclusion criteria were a history and physical exam consistent with primary LPD, and an MRI consistent with the diagnosis without other significant ligamentous injury. On MRI, location of cartilage, medial patellofemoral ligament (MPFL) injury, and bone bruising were noted. Severity was categorized as partial or complete for MPFL and cartilage lesions. Anatomic patellar instability risk factors (patella alta, trochlear dysplasia, increased TT-TG, and lateral patella tilt) were recorded and compared to the injury patterns. RESULTS: This study involved 157 patients; 107 patients were skeletally mature. Of the 157 patients, 26 had surgery for this injury due to clinician-perceived need for cartilage debridement. MPFL injury severity was complete rupture (N = 69, 44%), partial (N = 67, 43%), and none (N = 19, 13%). MPFL injury location was isolated femoral (N = 16, 10%), isolated patella (N = 26, 17%), isolated mid-substance (0%), multiple locations (N = 95, 61%), and none (N = 20, 13%). Chondral injury location was patella (N = 67, 43%), lateral femoral condyle (N = 11, 7%), multiple locations (N = 53, 34%), and none (N = 26, 17%). A majority (61%) of patellar chondral lesions were at its inferomedial aspect; all medial patellar retinacular partial injuries involved the inferomedial aspect of the patella, consistent with the insertion of the medial patellotibial ligament (MPTL). Skeletally immature patients had a greater risk of isolated patellar MPFL and chondral injury. No clear relationship was found between/across the location and/or severity of bone bruising, MPFL, or chondral injury. CLINICAL RELEVANCE: Underlying anatomic patellar instability risk factors defined by MRI, do not predict injury patterns. MPFL and chondral injury, as well as bone bruising, are common following LPD. The medial patellotibial ligament is torn in patellar-based medial retinacular injuries, based on MRI injury location. Skeletal immaturity plays a role in the location of the injury pattern with isolated patellar-based MPFL/chondral injury being more common in the skeletally immature patient. Sex does not appear to be a factor in injury patterns after primary LPD. Knowledge of these injury trends will help focus the clinician in injury evaluation when managing primary patellar dislocations. LEVEL OF EVIDENCE: Case series, Level IV.

Similar failure rate in immediate post-operative weight bearing versus protected weight bearing following meniscal repair on peripheral, vertical meniscal tears.

PURPOSE AND HYPOTHESIS: Post-operative weight bearing after meniscal repair is a point of debate among physicians. This study sought to evaluate whether patients adhering to an immediate WBAT rehabilitation programme have a higher failure rate compared to those adhering to a more traditional, protected, NWB status following meniscal repair. The null hypothesis was that there would be no difference in failure between the two groups. METHODS: A retrospective review of meniscal repair patients greater than 5 years from surgery was performed for patients receiving meniscal repair treatment. Patients were categorized by post-surgical weight-bearing status, either NWB or WBAT, and then analysed for failure of repair. Failure was defined as re-operation on the torn meniscus. The study controlled for variables including age at surgery, sex, height, weight, and BMI, classification of tear type, acuity of the tear, repair location (medial or lateral), repair location within the meniscus, repair technique, and concomitant procedures. RESULTS: Re-operations were performed in 61 of 157 patients [38.9%]. There was no difference between weight-bearing groups for failure of meniscus repair (n.s.). The tears were acute vertical tears located in the posterior horn and body. For the 61 patients with re-operation, the average time to re-operation was 2.2 years with 10 [16%] > 5 years from surgery, 17 [28%] 2-5 years from surgery, and 34 [56%] < 2 years from surgery. In isolated meniscal repair patients (n = 62), there was no difference between weight-bearing groups for rate of re-operation (n.s.). CONCLUSION: Weight bearing as tolerated after meniscal repair for peripheral, vertical tears does not result in a higher failure rate than traditional, non-weight bearing over a five-year follow-up period. The clinical relevance is that, based on these data, it may be appropriate to allow weight bearing as tolerated following meniscal repair of peripheral, vertical tears. LEVEL OF EVIDENCE: Retrospective cohort study, Level III.

What's New in Pediatric Upper Extremity Sports Injuries?

BACKGROUND: Sports injuries are common in pediatric and adolescent patients and the evaluation and treatment of these injuries continues to evolve. The purpose of this review is to provide a comprehensive appraisal of the most recent literature, highlighting updates on sports-related upper extremity injuries in pediatric patients. METHODS: An electronic search of the PubMed, EMBASE, and Google Scholar databases was performed for keywords related to pediatric overhead athletes, osteochondritis dissecans (OCD) of the capitellum, medial epicondyle fractures, shoulder instability, and clavicle fractures. Search results were filtered by publication date to yield articles published electronically or in print on or after January 1, 2013 to May 30, 2017. Papers were selected based on expert opinion and consensus by the authors and included if deemed to have contributed important findings to the above topics. RESULTS: A total of 51 articles were deemed to have contributed significant findings to the literature: 11 overhead athlete, 9 OCD of the capitellum, 6 medial epicondyle fractures, 17 shoulder instability, and 8 clavicle fractures. The level of evidence for most studies was either Level III or IV. CONCLUSIONS: Overuse and traumatic conditions of the pediatric elbow including UCL tear, capitellar OCD, and medial epicondyle fractures represent a significant portion of injuries in the overhead athlete. Research in the prevention and treatment of primary and recurrent shoulder instability in young athletes continues to evolve. The operative treatment of clavicle fractures in adolescents has been increasing without a commensurate increase in the level of evidence supporting such treatment. Advances have been made in the treatment of sports-related upper extremity injuries in pediatric patients, however, high-level, comparative outcomes research in many areas is lacking and this review may help inform topics for future study. LEVEL OF EVIDENCE: Level IV-Literature review.

What's New in Pediatric Sports Conditions of the Knee?

BACKGROUND: Sports injuries are common in pediatric and adolescent patients and the evaluation and treatment of these injuries continues to evolve. The purpose of this review is to provide a comprehensive appraisal of the literature, highlighting recent updates on sports-related knee injuries in the pediatric athlete. We specifically examined literature on tibial spine fractures, osteochondritis dissecans (OCD) of the knee, and patellar instability. Because of the volume of literature on the subject, pediatric, and adolescent anterior cruciate ligament injuries were not included in this review. METHODS: An electronic search of the PubMed, EMBASE, and Google Scholar databases was performed for keywords related to pediatric: tibial spine fractures, patellar instability, and osteochondritis dissecans (OCD). Search results were filtered by publication date to yield articles published electronically or in print on or after January 1, 2013. Papers were selected based on expert opinion and consensus by the authors and included if deemed to have contributed important findings to the above topics. RESULTS: A total of 31 articles were deemed to have contributed significant findings to the literature: 5 tibial spine, 17 patellar instability, and 9 OCD. The level of evidence for most studies was either level III or IV. CONCLUSIONS: The optimal treatment for tibial spine fractures remains controversial. The evaluation of risk factors for recurrent patellar instability is important in determining the optimal treatment strategy following first-time patellar dislocation. Future multicenter studies on pediatric OCD have the potential to further understanding of this difficult problem. High-level, comparative outcomes research on a variety of pediatric sports related injuries is lacking and this review may help inform topics for future study. LEVEL OF EVIDENCE: Level IV-literature review.

The angle of inclination of the native ACL in the coronal and sagittal planes.

PURPOSE: The purpose of this cross-sectional study was to evaluate the angle of inclination of the native anterior cruciate ligament (ACL) in both the sagittal and coronal planes and to evaluate these findings based on sex, height, BMI, and skeletal maturity. METHODS: Inclusion criteria for the study included patients undergoing routine magnetic resonance imaging (MRI) of the knee at a single outpatient orthopedic center who had an intact ACL on MRI. Measurements of the angle of inclination were made on MRIs in both the sagittal and coronal planes. Patients were compared based on sex, height, BMI, and skeletal maturity. RESULTS: One-hundred and eighty-eight patients were included (36 skeletally immature/152 skeletally mature; 98 male/90 female). The overall angle of inclination was 74.3° ± 4.8° in the coronal plane and 46.9° ± 4.9° in the sagittal plane. Skeletally immature patients (coronal: 71.8° ± 6.1°; sagittal: 44.7° ± 5.5°) were significantly different in both coronal and sagittal planes (P = 0.04 and 0.01, respectively) from skeletally mature patients (coronal: 75.3° ± 4.7°; sagittal: 47.4° ± 4.7°). There were no differences based on sex, height, or BMI. CONCLUSIONS: There are differences between the angle of inclination findings in this study and other studies, which could be due to MRI and measurement techniques. Clinically, skeletal maturity may be important to account for when using the ACL angle of inclination to evaluate anatomic ACL reconstruction. LEVEL OF EVIDENCE: Prognostic retrospective study, Level of evidence III.

An analysis of knee anatomic imaging factors associated with primary lateral patellar dislocations.

PURPOSE: Various knee anatomic imaging factors have been historically associated with lateral patellar dislocation. The characterization of these anatomic factors in a primary lateral patellar dislocation population has not been well described. Our purpose was to characterize the spectrum of anatomic factors from slice imaging measurements specific to a population of primary lateral patellar dislocation. A secondary purpose was to stratify these data by sex/skeletal maturity to better detail potential dimorphic characteristics. METHODS: Patients with a history of primary lateral patellar dislocation between 2008 and 2012 were prospectively identified. Ten MRI measurements were analysed with results stratified by sex/skeletal maturity. A '4-factor' analysis was performed to detail the number of 'excessive' anatomic factors within a single individual. RESULTS: This study involved 157 knees (79 M/78 F), and 107 patients were skeletally mature. The measurements demonstrate more anatomic risk factors in this population than historical controls. Patella height and trochlear measurements are the most common 'dysplastic' anatomic factors in this population. There were differences based on sex for some patellar height measurements and for TT-TG; there were no differences based on skeletal maturity. CONCLUSION: Primary lateral patellar dislocation patients have MRI measurements of knee anatomic factors that are generally more dysplastic than the normal population; however, there is a broad spectrum of anatomic features with no pattern predominating. Characterizing knee anatomic imaging factors in the patient with a primary lateral patellar dislocation is a necessary first step in characterizing the (potential) differences between the primary and recurrent patellar dislocation patient. LEVEL OF EVIDENCE: IV.