Swinging injuries in competitive baseball players.

Injuries are common in competitive baseball players and can occur in all facets of the game. The majority of the existing literature on injuries in baseball players has focused on injuries secondary to the overhead throw with very little attention given to injuries sustained while batting. The baseball swing is a complex, often violent, motion that predisposes batters to a variety of injuries affecting the spine, trunk, pelvis, and extremities. Knowledge of injury patterns that commonly occur during the baseball swing and radiologic findings important to the treating physician can help radiologists provide accurate imaging interpretations that appropriately guide patient management.

Talocalcaneal Tarsal Coalition Size: Evaluation and Reproducibility of MRI Measurements.

BACKGROUND: The size of talocalcaneal tarsal coalitions (TCCs) is one of the main factors that is thought to influence patient outcomes after resection. Magnetic resonance imaging (MRI) is increasingly being used to diagnose and characterize TCCs. However, there is no reproducible MRI-based measurement of TCC size reported in the literature. The purpose of this study was to create a method to reproducibly measure TCC size using MRI. METHODS: Twenty-seven patients with TCCs diagnosed by a hindfoot coronal proton density (PD) MRI between 2017 and 2020 were included. Five independent raters measured coalition width, healthy posterior facet width, and healthy middle facet width on individual slices of coronal PD hindfoot MRIs using discrete MRI measurement guidelines. Individual slice measurements were summed to determine total size of the coalition and the remaining healthy cartilage of the posterior and middle facets. Inter-rater reliability of MRI measurements between the 5 independent examiners was evaluated using intraclass correlation coefficient (ICC). ICC was calculated for total coalition width, total healthy posterior facet width, total coalition width/total healthy posterior facet width, total coalition width/total healthy middle facet width, total coalition width/total healthy subtalar facet width (posterior facet+middle facet), and total coalition width/total subtalar facet width (coalition+posterior facet+middle facet). RESULTS: The ICC scores for all but one of the MRI measurements indicated good to excellent inter-rater reliability among the 5 examiners. The ICC was 0.932 (95% confidence interval: 0.881-0.966) for measurement of total coalition width/total healthy posterior facet width and 0.948 (95% confidence interval: 0.908-0.973) for measurement of total coalition width/total subtalar facet width (middle+posterior+coalition). CONCLUSIONS: Measurements of coalition size using novel MRI guidelines were reproducible with good to excellent inter-rater reliability. These guidelines allow for determination of TCC size using coronal PD MRI. LEVEL OF EVIDENCE: Level II-diagnostic reproducibility study.

Evaluation of Osseous Incorporation After Osteochondral Allograft Transplantation: Correlation of Computed Tomography Parameters With Patient-Reported Outcomes.

BACKGROUND: Studies have reported favorable clinical outcomes after osteochondral allograft (OCA) transplantation to treat osteochondral defects and have demonstrated that healing of the osseous component may be critical to outcomes. However, there is currently no consensus on the optimal modality to evaluate osseous healing. PURPOSE: To define parameters for OCA healing using computed tomography (CT) and to investigate whether osseous healing identified using CT is correlated with improved pain and function on patient-reported outcomes (PROs) collected closest in time to the postoperative CT scan and at final follow-up. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Of 118 patients who underwent OCA transplantation for articular cartilage defects of the knee over the 10-year study period, 60 were included in final analysis based on completion of CT scans at 5.8 ± 1.9 months postoperatively and PROs collected preoperatively and postoperatively. CT parameters, including osseous incorporation, bone density, subchondral bone congruency, and cystic changes, were summarized for each patient relative to the cohort. Parameters were assessed for inter- and intrarater reliability as well as for covariation with patient characteristics and surgical variables. Structural equation modeling was used to assess correlation of CT parameters with change in PROs from preoperatively to those collected closest in time to CT acquisition and at the final follow-up. RESULTS: Bone incorporation was the most reliable CT parameter. The summarized scores for CT scans were normally distributed across the study population. Variance in CT parameters was independent of age, sex, body mass index, prior surgery, number of grafts, lesion size, and location. No significant correlation (P > .12 across all comparisons) was identified for any combination of CT parameter and change in PROs from baseline for outcomes collected either closest to CT acquisition or at the final follow-up (mean, 38.2 ± 19.9 months; range, 11.6-84.9 months). There was a uniformly positive association between change in PROs and host bone density but not graft bone density, independent of patient characteristics and surgical factors. CONCLUSION: CT parameters were independent of clinical or patient variables within the study population, and osseous incorporation was the most reliable CT parameter. Metrics collected from a single postoperative CT scan was not correlated with clinical outcomes at ≥6-month longitudinal follow-up.

Evaluation of Osseous Morphology of the Hip Using Zero Echo Time Magnetic Resonance Imaging.

BACKGROUND: Femoroacetabular impingement syndrome (FAIS) is a common disorder of the hip resulting in groin pain and ultimately osteoarthritis. Radiologic assessment of FAI morphologies, which may present with overlapping radiologic features of hip dysplasia, often requires the use of computed tomography (CT) for evaluation of osseous abnormality, owing to the difficulty of direct visualization of cortical and subchondral bone with conventional magnetic resonance imaging (MRI). The use of a zero echo time (ZTE) MRI pulse sequence may obviate the need for CT by rendering bone directly from MRI. PURPOSE/HYPOTHESIS: The purpose was to explore the application of ZTE MRI to the assessment of osseous FAI and dysplasia morphologies of the hip. It was hypothesized that angular measurements from ZTE images would show significant agreement with measurements obtained from CT images. STUDY DESIGN: Cohort study (diagnosis); Level of evidence, 2. METHODS: Thirty-eight hips from 23 patients were imaged with ZTE MRI and CT. Clinically relevant angular measurements of hip morphology were made in both modalities and compared to assess agreement. Measurements included coronal and sagittal center-edge angles, femoral neck-shaft angle, acetabular version (at 1-, 2-, and 3-o'clock positions), Tönnis angle, alpha angle, and modified-beta angle. Interrater agreement was assessed for a subset of 10 hips by 2 raters. Intermodal agreement was assessed on the complete cohort and a single rater. RESULTS: Interrater agreement was demonstrated in both CT and ZTE, with intraclass correlation coefficient values ranging from 0.636 to 0.990 for ZTE and 0.747 to 0.983 for CT, indicating "good" to "excellent" agreement. Intermodal agreement was also shown to be significant, with intraclass correlation coefficients ranging from 0.618 to 0.904. CONCLUSION: Significant agreement of angular measurements for hip morphology exists between ZTE MRI and CT imaging. ZTE MRI may be an effective method to quantitatively evaluate osseous hip morphology.

Fluoroscopically guided caudal epidural steroid injections for axial low back pain associated with central disc protrusions: a prospective outcome study.

PURPOSE: To determine if axial low back pain (LBP) associated with central disc protrusions can be improved by caudal epidural steroid injections (ESIs). METHODS: Adults with chronic (> 3 months) moderate-to-severe axial LBP with L4-5 and/or L5-S1 central disc protrusions were enrolled in this prospective study. Participants underwent caudal ESIs under standard-of-care practice. The numerical rating scale (NRS) pain score, modified North American Spine Society satisfaction, and Roland Morris Disability Questionnaire (RMDQ) were collected at one week, one month, three months, six months, and one year post-injection. Pre-injection magnetic resonance images were assessed by a musculoskeletal radiologist. RESULTS: Sixty-eight participants (42 males, 26 females) were analyzed. There were statistically significant improvements in all outcome measures at all follow-up time points, with the exception of NRS best pain at six months. Clinically significant improvements in outcomes were observed at various time points: at three months and one year for current pain; at one week, one month, three months, six months, and one year for worst pain; and at one month and one year for RMDQ. The proportion of satisfied participants ranged from 57 to 69% throughout the study. No adverse events were observed. CONCLUSIONS: This study demonstrated significant improvements in pain and function following caudal ESIs in a cohort of axial LBP with associated central disc protrusions. Further studies, including the use of randomized controlled trials, are needed to determine the ideal subset of candidates for this treatment and to explore additional applications that caudal ESIs may have for chronic LBP.

Magnetic resonance imaging of the quadriceps tendon autograft in anterior cruciate ligament reconstruction.

BACKGROUND: Quadriceps tendon (QT) autograft is emerging as a popular technique for primary anterior cruciate ligament (ACL) reconstruction. Studies have shown that it has comparable outcomes to bone-patellar tendon-bone (BPTB) and hamstring tendon (HT) autografts while mitigating post-operative complications associated with these grafts. PURPOSE: To provide a literature summary of the important pre- and post-operative magnetic resonance imaging (MRI) findings of the quadriceps tendon and pertinent postoperative complications associated with the QT harvest. Radiologists should be familiar with MR findings after autologous graft harvest of the quadriceps tendon for reconstruction of the ACL. LEVEL OF EVIDENCE: Level IV.

Correlation of Measurements of the Prearthritic Hip Between Plain Radiography and Computed Tomography.

BACKGROUND: Previous studies have compared radiographic and computed tomography (CT) imaging for the evaluation of prearthritic hip pain. However, the intermodality, interrater, and intrarater consistencies of those parameters have not been investigated. OBJECTIVE: To determine whether radiographs with an anteroposterior pelvis view and 45°-Dunn lateral view reliably correlate with CT in the context of lateral center edge (LCE), Tonnis, alpha, and beta angle measurements for femoroacetabular impingement or hip dysplasia diagnosis. DESIGN: Retrospective study. SETTING: Academic orthopedic institution. PATIENTS: Fifty consecutive participants with hip pain in the institutional hip registry with radiographs and CT imaging on file were evaluated between 2013 and 2014. MATERIALS AND METHODS: Radiologic data (50 CTs and 50 radiographs) were evaluated by 3 physicians. LCE, Tonnis, alpha, and beta angles were measured on radiographs and CTs in 2 rounds of readings. In round 1, the center of rotation on CT imaging was standardized by 1 rater. In round 2, individual raters chose CT images using a quadrant method, and reproducibility was assessed. Reliability statistics were operationalized with intraclass correlation coefficients (ICCs). MAIN OUTCOME MEASUREMENTS: Intermodality, intrarater, and interrater reliability of CT vs radiographic measurements. RESULTS: The intermodality reliability for all raters was excellent (ICC [95% CI]: 0.84 [0.76-0.90] to 0.97 [0.96-0.98]). Intrarater reliability for both modalities showed excellent reliability (ICC = 0.75-0.96). Interrater reliability of CT measures of LCE, Tonnis, and alpha angles demonstrated excellent agreement (ICC ≥ 0.88). Beta angle measures demonstrated good agreement (ICC [95% CI] = 0.68 [0.49-0.81]). Interrater reliability of radiographic measures showed excellent agreement (ICC = 0.82-0.94). CONCLUSION: Equivalent angle measurement readings on CT and radiographs were consistent among physicians. CT measurements correlated well with radiographic measurements. This suggests that if a standardized procedure is used to find the center of the femoral head, a positive correlation among LCE, alpha, beta, and Tonnis angles measured on CT can be obtained between multiple readers. LEVEL OF EVIDENCE: III.

Risk Factors for Nerve Injury After Total Hip Arthroplasty: A Case-Control Study.

BACKGROUND: Postsurgical acute nerve injury is rare but potentially devastating following total hip arthroplasty (THA). Previous literature suggests a wide range of incidence from 0.1% to 7.6%. Confirmed risk factors for these injuries remain unclear. METHODS: THA patients at our institution who developed nerve injury during their admission for THA between January 1, 1998, and December 31, 2013, were systematically identified and matched with 2 control subjects by surgical date. Relevant patient and surgical data were obtained through review of patient charts and electronic health records. We identified potential risk factors and calculated odds ratios (OR) using a conditional logistic regression model with a parsimonious stepwise approach. RESULTS: We identified 93 nerve injuries in 43,761 THAs (0.21%). The mean age of cases was 63 years. Adjusting for other factors in the model, patients <45 years were found to be at increased risk of developing nerve injury (OR, 7.17; P = .033). Similarly, patients with a history of tobacco use (OR, 1.90; P = .030) and a history of spinal surgery or disease (OR, 10.06; P < .001) were also associated with increased risk of nerve injury. For every 30-minute increase in surgery time after 1 hour, risk of nerve injury risk increased (OR, 1.48; P = .034). Assignment as first operative case of the morning was associated with a decreased risk of nerve injury (OR, 0.37, P = .043). CONCLUSION: This study demonstrates that nerve injury is a rare complication following THA at our institution. We found risk factors that are possibly modifiable factors such as lumbar spine disease, smoking, and time of surgical scheduling.

Prospective respiratory triggering improves high-resolution brachial plexus MRI quality.

BACKGROUND: Oblique sagittal MRI sequences, orthogonal to the longitudinal axis of the brachial plexus, can reliably depict morphologic and signal abnormalities. However, nerve visualization may be obscured by ghosting artifact from periodic respiratory motion. Respiratory triggering (RT) with a thoracoabdominal bellows can reduce ghosting artifact, but it is not routinely used for brachial plexus MRI. Furthermore, the efficacy of prospective RT for brachial plexus imaging has not yet been reported. PURPOSE: To compare brachial plexus MRI sequences acquired with and without respiratory triggering. STUDY TYPE: Prospective. SUBJECTS: Five volunteers and 20 patients were included. Each subject was imaged with and without RT during the same session. FIELD STRENGTH/SEQUENCE: Proton density or T2 -weighted Dixon fat suppressed sequences were obtained at 3.0T using receive-only 16-channel flexible array coils. ASSESSMENT: Three musculoskeletal radiologists blindly evaluated each sequence using subjective scoring criteria for ghosting artifact, nerve conspicuity, and diagnostic confidence. Nerve conspicuity scores at three distinct plexus levels were summed to calculate an overall image quality score. STATISTICAL TESTS: Marginal proportional odds logistic regression models were used to compare all scores between RT and non-RT. Gwet's agreement coefficient was used to assess interobserver and intraobserver reliability. RESULTS: Mean scan time per sequence increased from 4:25 minutes (95% confidence interval [CI], 4:02-4:49 min) with non-RT to 6:09 minutes (95% CI, 5:42-6:35 min) with RT. RT reduced ghosting artifact (odds ratio [OR] = 0.21, 95% CI: 0.09-0.46, P < 0.001), improved overall image quality (OR = 4.88, 95% CI: 2.18-10.95, P < 0.001), and increased diagnostic confidence (OR = 3.72, 95% CI: 1.61-8.63, P = 0.002) for all readers. Interobserver agreement for ghosting artifact and image quality was substantial to almost perfect (AC2 = 0.74-0.85). Interobserver agreement for all other scores was moderate to almost perfect (AC2 = 0.61-0.82). Intraobserver agreement was substantial to almost perfect for all parameters (AC2 = 0.76-1.0). DATA CONCLUSION: Prospective RT with bellows can effectively minimize ghosting artifact and improve image quality for brachial plexus MRI within clinically optimal acquisition times. LEVEL OF EVIDENCE: 1 Technical Efficacy: Stage 2.

Intramedullary Fixation of Distal Radius Fractures Using CAGE-DR Implant.

Purpose CAGE-DR implant is a novel Food and Drug Administration approved intramedullary fracture fixation device used for distal radius fractures. We examine a series of 22 patients and report the outcomes with this device. Materials and Methods A total of 24 patients with distal radius fractures (8 articular AO type C1/C2; 16 extra-articular AO type A2/A3) underwent open reduction and internal fixation (ORIF) using CAGE-DR implant by a single surgeon. Data including fracture type, angle of displacement, radiographic consolidation, grip strength, wrist range of motion (ROM), patient-rated wrist evaluation (PRWE), and Visual Analog Scale (VAS) pain scores were recorded at time of surgery and at standard follow-up. Results All 24 patients underwent uneventful ORIF. At first follow-up visit (9 days), all patients had full digital ROM (measured as 0 cm tip-to-palm distance). Two patients were lost to follow-up. Eighteen of the remaining 22 patients had sufficient radiographic follow-up and all 18 demonstrated healing. At latest follow-up (mean 9.7 months, range, 3-20), VAS pain scores averaged 0.6 (range, 0-8) and PRWE averaged 12.1 (range, 0-53.5). Grip strength of the operated hand averaged 58 lbs (range, 20-130). ROM included: wrist flexion 73° (50-95), wrist extension 78° (60-110), pronation 77° (60-90), supination 79° (60-90), ulnar deviation 31° (5-45), and radial deviation 17° (10-30). Three patients underwent screw removal to prevent tendon irritation. One patient underwent hardware removal due to prominence on imaging but was asymptomatic. There were otherwise no major complications, including complex regional pain syndrome, in the series to date. Conclusion The CAGE-DR fracture fixation system is a promising alternative to established methods of distal radius internal fixation. This series has a low reported pain score starting immediately postoperatively and a low complication rate. This novel device is a promising option for internal fixation of displaced distal radius fractures with a low complication profile. Level of Evidence This is a level IV, therapeutic study.

Improving registration accuracy during total hip arthroplasty: a cadaver study of a new, 3-D mini-optical navigation system.

INTRODUCTION: Maintaining accuracy of component placement is an important step in ensuring the long-term stability of components during total hip arthroplasty (THA). Computer-assisted navigation has improved accuracy but errors associated with the registration process are known to impact the accuracy of final measurements. The purpose of this cadaver study was to determine the registration error associated with a novel mini-navigation system. METHODS: 3 board-certified orthopaedic surgeons performed 4 THA procedures each via the posterolateral approach on 6 cadavers (12 hips) using the mini-navigation tool. Pre- and post-operative radiographs and post-operative computed tomography (CT) images were obtained. Image analysis was performed by 2 radiologists not involved in the surgical procedures. During registration, surgeons aligned the alignment rod with the anterior pelvic plane (APP) to provide a reference plane for comparison with traditional navigation. Cup position from the device was compared with measurements gathered from post-op imaging. RESULTS: The mean difference between CT and device measurements for inclination was -1.7° (standard deviation [SD] 4.9°), while the mean absolute difference was 4.2° (SD 3.2°). The mean difference between anteversion angles calculated from CT scans and from the device was -3.5° (SD 4.5°), with an absolute difference of 4.0° (SD 4.0°). 100% (12/12) of inclination measurements and 92% (11/12) of anteversion measurements fell within both the clinical and statistical limits of agreement when analyzed via the Bland-Altman technique. CONCLUSIONS: This study demonstrates that the registration error associated with this new mini-navigation system compares favourably with the known registration error associated with traditional navigation systems.

Risk factors for acute nerve injury after total knee arthroplasty.

INTRODUCTION: In this we study identified potential risk factors for post-total knee arthroplasty (TKA) nerve injury, a catastrophic complication with a reported incidence of 0.3%-1.3%. METHODS: Patients who developed post-TKA nerve injury from 1998 to 2013 were identified, and each was matched with 2 controls. A multivariable logistic regression model was built to calculate odds ratios (ORs). RESULTS: Sixty-five nerve injury cases were identified in 39,990 TKAs (0.16%). Females (OR 3.28, P = 0.003) and patients with history of lumbar pathology (OR 6.12, P = 0.026) were associated with increased risk of nerve injury. Tourniquet pressure < 300 mm Hg and longer duration of anesthesia may also be risk factors. DISCUSSION: Surgical planning for females and patients with lumbar pathology should be modified to mitigate their higher risk of neurologic complications after TKA. Our finding that lower tourniquet pressure was associated with higher risk of nerve injury was unexpected and requires further investigation. Muscle Nerve 57: 946-950, 2018.

Early clinical and radiological results of unilateral posterior pedicle instrumentation through a Wiltse approach with lateral lumbar interbody fusion.

BACKGROUND: To assess the clinical outcomes of 44 patients who underwent single-level lateral lumbar interbody fusion (LLIF) with unilateral pedicle screw instrumentation through a paramedian Wiltse approach. METHODS: Demographic, comorbidity, clinical assessment, peri-operative, and complication data were assessed. Visual analog scale (VAS), Oswestry disability index (ODI), and short form-12 (SF-12) were used to assess clinical outcomes. Post-operative plain radiographs were assessed for subsidence, cage migration, and fusion. RESULTS: Average age of patients at surgery was 60.8±10.6 years (range, 32-79 years), with 15 males and 29 females. Recombinant human bone morphogenic protein-2 (rhBMP-2) was used in 32 cases (73%) and 13 posterolateral fusions (30%). Average duration of surgery was 195.2±36.9 minutes (range: 111-295 minutes), with an estimated blood loss of 159.3±90.8 cc (range, 50-500 cc). There were no intra-operative complications. Average length of hospital stay was 4.2±2.5 days (range, 2-13 days). Four patients (9%) experienced neurological deficit, 2 of which resolved by 3-month follow-up and 2 of which improved but did not resolve by final follow-up at 11 and 16 months. There was significant improvement in VAS (P<0.001), ODI (P<0.001), and SF-12 physical component (P<0.001), but not for SF-12 mental component (P=0.053). Patients with minimum 6 months radiographic follow-up demonstrated successful fusion in 90% of cases (35/39), with 2 cases of grade 1 (5%) subsidence of the adjacent cranial vertebra, and no cases higher than grade 0 subsidence of the adjacent caudal vertebra. CONCLUSIONS: Unilateral pedicle screw instrumentation following LLIF was associated with significant improvement in clinical outcomes and favorable radiographic outcomes.

Quantification of Imaging Error in the Measurement of Cup Position: A Cadaveric Comparison of Radiographic and Computed Tomography Imaging.

Postoperative radiographs remain the standard for assessment of component placement following total hip arthroplasty (THA), despite the known limitations of radiographs. Computed tomography (CT) scanning offers improved accuracy, but its costs and radiation exposure are prohibitive. The authors performed a cadaver study to compare the error associated with radiographs with that of CT scans following THA. The authors also compared imaging with a novel mini-navigation system. Three board-certified orthopedic surgeons each performed 4 THA procedures (6 cadavers, 12 hips) via the posterior approach using a mini-navigation tool to assist with component placement. Cup position from imaging was compared with corrected CT values for anteversion and inclination, created by correcting the initial scan to align the anterior pelvic plane coplanar with the CT table, thus representing cup position not distorted by imaging or positioning. Anteversion from standard CT scans was within 2.5° (standard deviation [SD], 1.5°) of reference values (P=.25); radiographs showed an average error of 7.8° (SD, 4.3°) vs reference values (all values absolute means) (P<.01). The mini-navigation system provided anteversion values within an average of 4.0° (SD, 4.0°) of reference anteversion (P<.01). Standard CT values for inclination were within 2.4° (SD, 2.0°) of reference values (P=.53), whereas radiographic inclination values were within 2.5° (SD, 2.3°) (P=.12). Mini-navigation values for inclination were within 3.9° (SD, 3.2°) of reference inclination (P=.26). This study demonstrated that cup position as measured by radiographs is significantly less accurate than CT scans and that the mini-navigation system provided anteversion measurements that were of comparable accuracy to CT scans. [Orthopedics. 2017; 40(6):e952-e958.].

A Cadaver Study to Evaluate the Accuracy of a New 3D Mini-Optical Navigation Tool for Total Hip Arthroplasty.

BACKGROUND: Accurate measurement of acetabular cup position (CP), changes in leg length (LL), and offset (OS) are paramount in ensuring proper sizing and implantation of components during total hip arthroplasty (THA). LL/OS inaccuracies can cause low back pain, neurological deficits, and patient dissatisfaction, while inaccurate positioning of the acetabular cup can lead to instability, dislocation, and, ultimately, revision surgery. The objective of this study was to evaluate the accuracy of a mini-navigation tool in measuring CP and LL/OS differential during THA. MATERIALS AND METHODS: Three board-certified orthopedic surgeons each performed four THA procedures via the posterior approach on six cadavers (12 hips) utilizing a novel mini-navigation tool. Imaging included pre- and post-operative radiographs and post-operative CT scans. Image analysis was performed by two radiologists not involved in the surgical procedures. System accuracy regarding measurement of cup position (anteversion and inclination) was determined by comparing the CT measurement of cup orientation with data gathered intraoperatively by probing the face of the implanted cup with the navigation tool and recording the coordinates. RESULTS: The mean absolute difference between CT and device measurements of cup position was 0.74º (SD: 0.47, range: 0.19-1.48) for anteversion and 0.97º (SD: 0.67, range: 0.27-2.57) for inclination. The mean difference between device and radiograph measurements of LL changes was 0.27 mm (SD: 3.61, range: -5.20-7.78) (absolute mean: 2.71±2.25 mm), while the mean difference in OS was 1.75 mm (SD: 3.00, range: -2.47-6.65) (absolute mean: 2.37±2.44 mm). CONCLUSIONS: This novel mini-navigation tool measured CP, LL, and OS accurately when compared with implant position measured on imaging.

MR Imaging in Postreduction Assessment of Developmental Dysplasia of the Hip: Goals and Obstacles.

Developmental dysplasia of the hip is a spectrum disorder of hip development that ranges in severity from abnormal acetabular morphology to complete hip dislocation. While treatment with a Pavlik harness is highly effective in infants younger than 6 months, older infants and children and those with orthotic failure often warrant surgical reduction and placement of a spica cast, which limits subsequent imaging evaluation. Magnetic resonance (MR) imaging has been described in the evaluation of the adequacy of hip reduction for more than 2 decades, but the practice is still not widespread and is performed routinely at relatively few centers. MR imaging is a robust tool for outcome assessment after hip reduction and placement of a spica cast, facilitating multiplanar confirmation of concentric reduction independent of an ossific nucleus or orthopedic hardware. Excellent image contrast of soft tissues allows identification of obstacles to concentric reduction, which may be extra-articular or intra-articular. Extra-articular obstacles include tightening of the adductor muscles and tightening of the iliopsoas tendon with constriction of the joint capsule. Intra-articular obstacles include limbus formation, labral inversion, an enlarged pulvinar, and hypertrophy of the ligamentum teres and/or the transverse acetabular ligament. Intravenous contrast material administration may demonstrate altered epiphyseal blood flow and help identify patients at risk for early ischemia. Imaging technique and image interpretation can be optimized to facilitate the performance of postreduction MR imaging studies where they may be of benefit. (©)RSNA, 2016.

Severe Hand Osteoarthritis Strongly Correlates With Major Joint Involvement and Surgical Intervention.

BACKGROUND: The presence of hand osteoarthritis (OA) increases the risk for developing OA in other major joints. Although genetic predisposition has been implicated in its causation, its exact role has yet to be established. The association of hand OA with symptomatic and asymptomatic major joints has not been previously studied. METHODS: Hundred consecutive patients had a hand photo taken for visual documentation of the hand joints. Radiographs of hand and all major symptomatic joints were analyzed and classified using the Kellgren-Lawrence scale by 2 independent observers including an orthopedic radiologist. RESULTS: Severe hand OA was present in 91% of the patients. Radiographic analysis showed that the hip was involved in 88% of the patients, of whom 85.2% (75) were symptomatic and 14.7% (13) were asymptomatic. Hip arthroplasty was required by 62.5% (55) of symptomatic hip patients. Knee involvement was present in 37% of the patients; all were symptomatic and 81.1% (30) of these required knee arthroplasty. Bilateral surgery was performed in 33% (28) and "2 joint (hip and knee)" surgery was performed in 6% (5). Spine involvement was present in 72% of the patients. There was a significant correlation between hand radiographic findings of OA and hip (r = 0.68; P = .03), knee (r = 0.58; P = .042), and spine (r = .39; P = .05) involvement. CONCLUSION: There was a significant correlation between severe hand OA and hip, knee, and spine involvement. Severity of Hand OA can have a predictive value on multiple joint involvement and risk of surgical intervention. This study emphasizes the need to investigate the genetic predisposition in causation of OA.

Magnetic resonance imaging evaluation of the painful total knee arthroplasty.

Optimization of metal artifact reduction pulse sequences over the past decade has rendered MRI valuable in knee arthroplasty assessment. MRI can reliably predict the presence and extent of infection, component loosening and polyethylene wear, and component malrotation, and it can evaluate the integrity of surrounding soft tissue structures. Using dynamic contrast-enhanced angiographic techniques, vascular pathology such as pseudoaneurysm formation and recurrent hemarthrosis can also be assessed.

Secondary ossification centers in the development of the medial malleolus.

BACKGROUND: Accessory ossicles of the medial malleolus have been reported, however, these have not been linked to a pattern of development and are considered anomalies. Here, we describe a pattern of ossification of the medial malleolus in children including a secondary ossification center. METHODS: Twenty anteroposterior (AP) and mortise x-rays of each sex and age from 4 to 12 were randomly selected from skeletally immature patients identified at our institution. X-rays were excluded if there was a cast or splint, fracture, hardware, or obvious tibial deformity. Each x-ray was evaluated and categorized to a 4-part stage of development. These stages were then applied to randomly selected AP hip to ankle films from the same age groups. RESULTS: Four distinct stages of medial malleolus ossification were identified on ankle x-rays. Stage 1 consists of the widening of the epiphysis that did not reach the medial border of the metaphysis. In stage 2, the epiphysis had widened medially to the level of the metaphysis, however, had not extended distally to the level of the dome of the talus. In stage 3, the proximal portion of the medial malleolus has ossified distal to the dome of the talus with ossification centers at this level identified. Stage 4 consisted of a completely fused ossification center extending distally to a mature medial malleolus. The stages were reconfirmed on AP standing hip to ankle to have a similar distribution, secondary ossification centers were more common in females aged 6 to -9 and males aged 8 to 11 years. CONCLUSIONS: The medial malleolus develops in predictable stages which may involve a secondary ossification center in the final stages of development. These findings were initially described on AP and mortise views, then confirmed on AP hip to ankle radiographs were evaluated to exclude potentially confounding ankle pain. These secondary ossification centers were seen at similar ages on both ankle and hip to ankle x-rays. LEVEL OF EVIDENCE: Level III.