Delays in the Reticulospinal System Are Associated With a Reduced Capacity to Learn a Simulated Feeding Task in Older Adults.

Learning declines with age. Recent evidence indicates that the brainstem may play an important role in learning and motor skill acquisition. Our objective was to determine if delays in the reticular formation, measured via the startle reflex, correspond to age-related deficits in learning and retention. We hypothesized that delays in the startle reflex would be linearly correlated to learning and retention deficits in older adults. To determine if associations were unique to the reticulospinal system, we also evaluated corticospinal contributions with transcranial magnetic stimulation. Our results showed a linear relationship between startle onset latency and percent learning and retention but no relationship between active or passive motor-evoked potential onsets or peak-to-peak amplitude. These results lay the foundation for further study to evaluate if (1) the reticular formation is a subcortical facilitator of skill acquisition and (2) processing delays in the reticular formation contribute to age-related learning deficits.

Micro Screw Fixation for Small Proximal Pole Scaphoid Fractures with Distal Radius Bone Graft.

Background Achieving adequate fixation and healing of small proximal pole acute scaphoid fractures can be surgically challenging due to both fragment size and tenuous vascularity. Purpose The purpose of this study was to demonstrate that this injury can be managed successfully with osteosynthesis using a "micro" small diameter compression screw with distal radius bone graft with leading and trailing screw threads less than 2.8 mm. Patients and Methods Patients with proximal pole scaphoid fragments comprising less than 20% of the entire scaphoid were included. Fixation was accomplished from a dorsal approach with a micro headless compression screw and distal radius bone graft. Six patients were included. Average follow-up was 44 months (range, 11-92). Results Mean proximal pole fragment size was 14% (range, 9-18%) of the entire scaphoid. The mean immobilization time was 6 weeks, time-to-union of 6 weeks, and final flexion/extension arc of 88°/87°. All patients had a successful union, and no patient had deterioration in range of motion, avascular necrosis, or fragmentation of the proximal pole. Conclusion Small diameter screws with a maximal thread diameter of ≤ 2.8 mm can be used to fix the union of proximal pole acute scaphoid fractures comprising less than 20% of the total area with good success. Level of Evidence Therapeutic case series, Level IV.

Comparative Evaluation of Surgical Procedures with Clinical Equipoise: the Unique Perspective of Our Hand Therapy Colleagues.

BACKGROUND: There are several accepted surgical treatment options available for carpal tunnel syndrome, thumb carpometacarpal joint (CMC), osteoarthritis (OA), and wrist degenerative joint disease. QUESTIONS/PURPOSES: We sought to obtain the views and preferences from a cohort of certified hand therapists (CHT) and hypothesized that this source may identify differences in procedures that are otherwise widely believed to have clinical equipoise. METHODS: Five hundred twelve CHTs were surveyed regarding their experience, volume, and referral base along with their subjective assessments and preferences regarding open versus endoscopic carpal tunnel release (CTR), various surgical procedures for CMC OA, and proximal row carpectomy (PRC) versus 4-corner fusion (4-CF). RESULTS: The average CHT surveyed had 15.2 years experience and had a referral base of 7.7 different hand surgeons. Twenty-seven percent of respondents perceived superior pain control and incisional tenderness following open CTR compared to that of endoscopic CTR. However, 68% of CHTs would elect to undergo an open CTR themselves. There was no clear consensus for the optimal reconstructive technique for thumb CMC OA. As compared to that of 4-CF, PRC was thought to result in superior pain control (34 versus 22%), motion (43 versus 18%), and earlier discharge from therapy (32 versus 19%); however, 53% of respondents would prefer a 4-CF for themselves. CONCLUSIONS: Hand therapists are intimately involved in the care of surgical patients and provide an educated and unique source for evaluating postoperative outcomes.

Changes in Local Bone Density in Early Thumb Carpometacarpal Joint Osteoarthritis.

PURPOSE: Thumb carpometacarpal (CMC) osteoarthritis (OA) represents a major source of functional morbidity. The effects of early CMC OA on loading and use patterns potentially lead to changes in local bone density and microarchitecture. Hounsfield units (HU), a quantitative attenuation coefficient obtained from computed tomography (CT) scans, have been shown to be a reliable marker of bone density. We hypothesized that early CMC OA is associated with lower local bone density about the CMC joint as assessed by HU. METHODS: We examined HU units from CT scans in 23 asymptomatic subjects and 91 patients with early CMC OA. The HU measurements were obtained within cancellous portions of the trapezium, capitate, first and third metacarpal bases, and distal radius. Linear regression models, with age and sex included as covariates, were used to assess the relationship between CMC OA and HU values at each anatomical site. RESULTS: Early OA patients had significantly lower HU than asymptomatic subjects within the trapezium (mean, 377 HU vs 436 HU) and first metacarpal bases (265 HU vs 324 HU). No significant group differences were noted at the capitate, third metacarpal, or distal radius. Male sex and younger age were associated with significantly higher HU at all the anatomical sites, except the first metacarpal base, where age had no significant effect. CONCLUSIONS: Subjects presenting with early CMC OA had significantly lower bone density as assessed with HU at the thumb CMC joint (trapezium and first metacarpal base). Early thumb CMC OA and discomfort may lead to diminished loading across the basal joint, producing focal disuse osteopenia. These findings in symptomatic early arthritis suggest a relationship between symptoms, functional use of the CMC joint, and local bone density. TYPE OF STUDY/LEVEL OF EVIDENCE: Diagnostic II.

Opportunistic Use of CT Imaging for Osteoporosis Screening and Bone Density Assessment: A Qualitative Systematic Review.

BACKGROUND: The purpose of this study was to determine the clinical opportunities for the use of computed tomography (CT) imaging for inferring bone quality and to critically analyze the correlation between dual x-ray absorptiometry (DXA) and diagnostic CT as reported in the literature. METHODS: A systematic review of the MEDLINE database was performed in February 2016 using the PubMed interface. The inclusion criteria were English language, studies performed using living human subjects, studies pertaining to orthopaedics, use of conventional diagnostic CT scans, studies that measured cancellous bone, and studies that reported Hounsfield unit (HU) measurements directly rather than a computed bone mineral density. RESULTS: Thirty-seven studies that reported on a total of 9,109 patients were included. Of these, 10 studies correlated HU measurements of trabecular bone with DXA-based bone assessment. Reported correlation coefficients ranged between 0.399 and 0.891, and 5 of the studies reported appropriate threshold HU levels for diagnosing osteoporosis or osteopenia. CONCLUSIONS: Direct HU measurement from diagnostic CT scans has the potential to be used opportunistically for osteoporosis screening, but in its current state it is not ready for clinical implementation. There is a lack of exchangeability among different machines that limits its broad applicability. Future research efforts should focus on identifying thresholds at specific anatomic regions in high-risk patients in order to have the greatest impact on patients. However, using diagnostic CT to infer region-specific osteoporosis could be extraordinarily valuable to orthopaedic surgeons and primary care physicians, and merits further research.

Simple Assessment of Global Bone Density and Osteoporosis Screening Using Standard Radiographs of the Hand.

PURPOSE: Osteoporosis and fragility fractures have consequences both at the individual level and to the overall health care system. Although dual-energy x-ray absorptiometry (DXA) is the reference standard for assessing bone mineral density (BMD), other, simpler tools may be able to screen bone quality provisionally and signal the need for intervention. We hypothesized that the second metacarpal cortical percentage (2MCP) calculated from standard radiographs of the hand or wrist would correlate with hip BMD derived from DXA and could provide a simple screening tool for osteoporosis. METHODS: Two hundred patients who had hand or wrist radiographs and hip DXA scans within 1 year of each other were included in this series. Mid-diaphyseal 2MCP was calculated as the ratio of the cortical diameter to the total diameter. We assessed the correlation between 2MCP and total hip BMD. Subjects were stratified into normal, osteopenic, and osteoporotic cohorts based on hip t scores, and thresholds were identified to optimize screening sensitivity and specificity. RESULTS: Second metacarpal cortical percentage correlated significantly with BMD and t scores from the hip. A 2MCP threshold of less than 60% optimized sensitivity (88%) and specificity (60%) for discerning osteopenic subjects from normal subjects, whereas a threshold of less than 50% optimized sensitivity (100%) and specificity (91%) for differentiating osteoporotic from normal subjects. CONCLUSIONS: By demonstrating that global BMD may be assessed from 2MCP, these data suggest that radiographs of the hand and wrist may have a role in accurately screening for osteopenia and osteoporosis. This simple investigation, which is already used ubiquitously for patients with hand or wrist problems, may identify patients at risk for fragility fractures and allow for appropriate referral or treatment. TYPE OF STUDY/LEVEL OF EVIDENCE: Diagnostic II.

Assessment of Vertebral Curves Using the Manual Post-It Technique.

STUDY DESIGN: A prospective study of a new technique. OBJECTIVE: The aims of this study were to report a manual technique for measuring vertebral curves on digital spine radiographs, and to assess the agreement of this technique with that of digital software for measuring vertebral curves. SUMMARY OF BACKGROUND DATA: Modern picture archiving and communication systems (PACS) typically include software for evaluating radiographic measurements. However, in the outpatient spine setting, patients may present with radiographs stored on a physical disc, which may not include software for measuring vertebral curves. Certain smartphone applications may be used to determine curve magnitude; however, the need exists for an accurate manual technique to measure vertebral curves on digital radiographs in the absence of available analytic software or smartphone technology. METHODS: We prospectively reviewed anteroposterior and lateral spine radiographs of 24 spinal deformity patients. Two independent observers measured Cobb angles for: (1) the major coronal curve; (2) the thoracic kyphosis (T2-T12); and (3) the lumbar lordosis (T12-S1). Measurements were made: (1) digitally using our institution's PACS; and (2) by a manual technique, which involves placement of an adhesive Post-It note directly on the computer screen, transcribing the angle onto the Post-It note with a pencil, and measuring the angle with a handheld goniometer. Intraclass correlation coefficients (ICCs) were calculated to determine the agreement between the 2 methods. RESULTS: For both observers, the agreement between the digital PACS and manual Post-It techniques was graded as excellent for both coronal and sagittal plane curves (all ICCs>0.9). Interobserver reliability between the 2 observers was also graded as excellent for both the PACS and Post-It techniques (all ICCs>0.9). CONCLUSIONS: The Post-It technique for measuring Cobb angles demonstrated excellent agreement with the PACS system in our series of spinal deformity patients. Curves on digital radiographs can be accurately measured using a convenient manual technique.

Axon Counts Yield Multiple Options for Triceps Fascicular Nerve to Axillary Nerve Transfer.

PURPOSE: To evaluate the relative axonal match between potential donor and recipient nerves, so that maximal reinnervation potential may be reached with the least chance of donor site morbidity. METHODS: In 10 fresh-frozen cadaveric specimens, the main trunk and anterior, posterior, sensory and teres minor branches of the axillary nerve were identified, as were the radial nerve branches to the long, medial, and lateral heads of the triceps. The swing distances of the triceps fascicular nerve branches and the axillary nerve branches relative to the inferior border of the teres major muscle were recorded. Histomorphological analysis and axon counts were performed on sections of each branch. RESULTS: The median number of axons in the main axillary trunk was 7,887, with 4,052, 1,242, and 1,161 axons in the anterior, posterior, and teres minor branches, respectively. All specimens had a single long head triceps branch (median, 2,302 axons), a range of 1 to 3 branches to the medial head of the triceps (composite axon count, 2,198 axons), and 1 to 3 branches to the lateral head of the triceps (composite average, 1,462 axons). The medial and lateral head branches had sufficient swing distance to reach the anterior branch of the axillary nerve in all 10 specimens, with only 4 specimens having adequate long head branch swing distances. CONCLUSIONS: It is anatomically feasible to transfer multiple branches of the radial nerve supplying the medial, lateral, and sometimes, long head of the triceps to all branches of the axillary nerve in an attempt to reinnervate the deltoid and teres minor muscles. CLINICAL RELEVANCE: Understanding the axon counts of the different possible transfer combinations will improve operative flexibility and enable peripheral nerve surgeons to reinnervate for both abduction and external rotation with the highest donor/recipient axon count ratios.

Blunt Force May be an Effective Treatment for Ganglion Cysts.

BACKGROUND: Ganglion cysts are the most common soft tissue tumors of the hand and wrist. There is currently no data available for the recurrence or complication rate of patients that self treat ganglion cysts by using an extrinsic force. Despite this absence of evidence, patients are still using this mode of treatment. QUESTIONS/PURPOSES: The purpose of the study is to evaluate the efficacy of blunt force as a treatment modality for disrupting ganglion cysts. METHODS: We analyzed videos of patients attempting to disrupt their ganglion cysts of the wrist by blunt force on Youtube.com and surveyed them anonymously. Candidates were contacted through YouTube's email server and given a link to an online questionnaire. RESULTS: Two hundred fourteen individuals were reviewed with a total of 1,008,913 views. Eighty three percent of videos were effective in treating the cyst. All 38 individuals that responded to the survey reported that the blunt force was effective in immediate elimination of the cyst in an average of 1.6 attempts (range 1-5). A majority (N = 21, 55%) reported no recurrence since the initial disruption of the cyst at a follow-up of 24 months. CONCLUSIONS: YouTube.com was found to be an effective outlet to study a treatment modality that would otherwise be limited by practical considerations. The study showed that a subset of patients is utilizing blunt force trauma to successfully treat wrist ganglion cysts.

Using Hounsfield Units to Assess Osteoporotic Status on Wrist Computed Tomography Scans: Comparison With Dual Energy X-Ray Absorptiometry.

PURPOSE: Rates of evaluation and treatment for osteoporosis following distal radius fragility fractures remain low. As a subset of patients with these fractures undergo diagnostic computed tomography (CT) scan of the wrist, utilizing bone mineral density (BMD) measurements available with this imaging can be used to detect osteopenia or osteoporosis. This information may consequently prompt intervention to prevent a subsequent fracture. The purpose of this study was to determine if Hounsfield unit (HU) measurements at the wrist correlate with BMD measurements of the hip, femoral neck, and lumbar spine and to assess the ability of these HU measurements to detect osteoporosis of the hip. METHODS: Forty-five female patients with distal radius fractures who underwent CT scan and dual energy x-ray absorptiometry scan as part of the management of their wrist fracture were identified. Bone mineral density measurements were made using the regional cancellous bone HU value at the capitate and compared with values obtained by a dual energy x-ray absorptiometry scan. RESULTS: Hounsfield unit values at the capitate were significantly correlated with BMD and t scores at the femoral neck, hip, and lumbar spine. An HU threshold of 307 in the capitate optimized sensitivity (86%) and specificity (94%) for detecting osteoporotic patients. CONCLUSIONS: By demonstrating that capitate HU measurements from clinical CT scans are correlated with BMD and t scores at the hip, femoral neck, and lumbar spine, our data suggest that clinical CT scans should have a role in detecting osteopenia and osteoporosis. TYPE OF STUDY/LEVEL OF EVIDENCE: Diagnostic III.

Opportunistic Osteoporosis Screening - Gleaning Additional Information from Diagnostic Wrist CT Scans.

BACKGROUND: Although screening for and treating osteoporosis can prevent subsequent fractures, the rates of such interventions are low following a distal radial fracture. One potential method for identifying metabolic bone disease is via Hounsfield unit (HU) measurements from diagnostic computed tomography (CT) scans. We hypothesized that HU values of the distal aspect of the radius could be used to assess local bone quality and would be predictive of distal radial fracture risk, thereby allowing the identification of patients in need of further management. METHODS: Measurements of bone mineral density (BMD) were made for 100 patients on the basis of HU values of cancellous portions of the distal aspect of the radius, the ulnar head, and the capitate. The HU values in twenty-five male and twenty-five female patients with an acute distal radial fracture documented on CT were compared with those of age and sex-matched control patients who had a CT scan obtained for other indications. RESULTS: Among the control patients, HU values decreased as age increased. When assessed on the basis of sex, both male and female patients with a distal radial fracture had significantly lower regional BMD compared with nonfracture control patients. A distal radial HU value of 218 for females and 246 for males optimized sensitivity and specificity; values below this threshold were associated with an increased risk of distal radial fracture. CONCLUSIONS: HU measurements can be obtained from any diagnostic CT scan using modern software programs and can be obtained by physicians in the office setting with minimal effort and at no additional cost or radiation exposure to the patient. Regardless of imaging indications, we suggest that patients with HU values below the identified thresholds be considered for further metabolic bone disease work-up, such as additional imaging, laboratory assessments, the initiation of osteoporosis treatment, or appropriate referral.

Circulating precursors of human CD1c+ and CD141+ dendritic cells.

Two subsets of conventional dendritic cells (cDCs) with distinct cell surface markers and functions exist in mouse and human. The two subsets of cDCs are specialized antigen-presenting cells that initiate T cell immunity and tolerance. In the mouse, a migratory cDC precursor (pre-CDC) originates from defined progenitors in the bone marrow (BM). Small numbers of short-lived pre-CDCs travel through the blood and replace cDCs in the peripheral organs, maintaining homeostasis of the highly dynamic cDC pool. However, the identity and distribution of the immediate precursor to human cDCs has not been defined. Using a tissue culture system that supports the development of human DCs, we identify a migratory precursor (hpre-CDC) that exists in human cord blood, BM, blood, and peripheral lymphoid organs. hpre-CDCs differ from premonocytes that are restricted to the BM. In contrast to earlier progenitors with greater developmental potential, the hpre-CDC is restricted to producing CD1c(+) and CD141(+) Clec9a(+) cDCs. Studies in human volunteers demonstrate that hpre-CDCs are a dynamic population that increases in response to levels of circulating Flt3L.

Conservative management of elbow dislocations with an overhead motion protocol.

PURPOSE: To report the results of using an overhead motion protocol in 27 patients and to assess final range of motion and incidence of persistent instability in this cohort. METHODS: A total of 27 patients were included who sustained a simple elbow dislocation and were treated nonsurgically with an overhead motion protocol designed to convert gravity from a distracting to a stabilizing force. Motion was initiated within 1 week of injury and average follow-up was 29 months. Final arc of motion and prevalence of instability were the primary outcomes measures. RESULTS: Final mean arc of extension to flexion was from 6° to 137°, and of pronation to supination was from 87° to 86°. No recurrent instability was observed in this cohort and all patients were fully functional and without limitations at latest follow-up. CONCLUSIONS: The overhead motion protocol was a reliable rehabilitation program after elbow dislocation that allowed for controlled early motion by placing the elbow in an inherently stable position. Prompt initiation of motion in a protected position can optimize final motion and satisfaction outcomes, and when done in a mechanically advantageous position it can potentially limit the risk of recurrent instability. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

Optimal axon counts for brachial plexus nerve transfers to restore elbow flexion.

BACKGROUND: Nerve transfer surgery has revolutionized the management of traumatic brachial plexus injures. However, the optimal size ratio of donor to recipient nerve has yet to be elucidated. The authors investigated the axon count ratios of ulnar and median fascicular transfers to restore elbow flexion. The authors hypothesized that donor nerve axon counts would be correlated with historical success of various nerve transfers used to restore elbow flexion. METHODS: Ten cadaveric specimens were used for a histomorphologic analysis of fascicular nerve transfers. Review of previously published axon counts and clinical results following transfer to the musculocutaneous nerve to restore elbow flexion was performed for the following donor nerves: medial pectoral, spinal accessory, intercostal, thoracodorsal, ulnar, and median fascicular. RESULTS: The average number of fascicles identified was 7.9 in the ulnar nerve and 8.0 in the median nerve. The mean fascicular axon count was 1318 for the ulnar nerve and 1860 for the median nerve. Mean recipient nerve axon count was 1826 for the musculocutaneous biceps branch and 1840 for the brachialis branch. A significant correlation between axon count and clinical results of transfers to restore elbow flexion was observed. Donor-to-recipient nerve axon count ratios below 0.7:1 were associated with a decreased likelihood of a successful outcome. CONCLUSIONS: In nerve transfers to restore elbow flexion, an appropriate size match between donor and recipient nerves appears to be a factor affecting clinical success. These data support a donor-to-recipient axon count ratio greater than 0.7:1 as the goal for brachial plexus nerve transfers to restore elbow flexion.

Outcomes of anconeus interposition for proximal radioulnar synostosis.

BACKGROUND/HYPOTHESIS: Proximal radioulnar synostosis after elbow injuries can produce debilitating contractures. The estimated range of motion required to perform many activities of daily living is a 100° arc of forearm rotation. We hypothesized that excision of heterotopic bone and anconeus flap interposition could restore functional prono-supination in patients with proximal radioulnar synostosis. METHODS: Patients with proximal radioulnar synostosis were subdivided into 2 groups on the basis of etiology: (1) as a complication after distal biceps tendon repair or (2) as a result of direct trauma to the proximal forearm/elbow. All patients underwent an excision of the synostosis with interposition of an anconeus flap and were observed clinically for a minimum of 6 months. RESULTS: Twenty-three patients (16 men, 7 women) were included, with a mean age of 47 years and mean clinical follow-up of 4.8 years. Mean arc of forearm rotation improved from 21° to 132°, pronation increased from 12° to 70°, and supination increased from 9° to 62° (P < .0001). Patients with biceps tendon repair etiology (n = 7) displayed greater gains in pronation and a trend toward greater total forearm rotation than did those with a traumatic etiology (n = 16). CONCLUSION: Anconeus interposition flap for management of proximal radioulnar synostosis produces significant and reliable clinical improvement in elbow prono-supination. Patients with biceps tendon repair etiology had a trend toward greater motion improvement than that of patients with a traumatic etiology. The degree of improvement seen would provide nearly full restoration of functional motion, resulting in minimal limitations in activities of daily living.

Thoracic outlet syndrome caused by synostosis of the first and second thoracic ribs: 2 case reports and review of the literature.

We present 2 cases of combined arterial and neurogenic thoracic outlet syndrome triggered by trauma in patients with congenital synostoses of the first and second ribs. These patients were successfully treated with supraclavicular resection of the first and second ribs and scalenectomy. We review these cases and the associated literature on thoracic outlet syndrome and rib synostosis.

Use of computed tomography for assessing bone mineral density.

Assessing local bone quality on CT scans with Hounsfield unit (HU) quantification is being used with increasing frequency. Correlations between HU and bone mineral density have been established, and normative data have been defined throughout the spine. Recent investigations have explored the utility of HU values in assessing fracture risk, implant stability, and spinal fusion success. The information provided by a simple HU measurement can alert the treating physician to decreased bone quality, which can be useful in both medically and surgically managing these patients.

Direct repair for managing acute and chronic lateral ulnar collateral ligament disruptions.

PURPOSE: Acute elbow injuries that disrupt the lateral ulnar collateral ligament and result in posterolateral rotatory instability usually require surgical treatment. The 2 technical options reported, direct repair and use of a palmaris longus tendon graft, have usually favored the use of the graft. To balance this emphasis, we report our experience with direct repair of the humeral origin in cases of trauma, whether acute, delayed, or recurrent. It was our hypothesis that because the humeral origin is the point of failure and separation, restoration of this attachment is sufficient to restore stability and durable function without the need for a graft. METHODS: Patients with complete disruption of the posterolateral ligaments of the elbow, who were managed with direct repair to the humeral origin, were included. Patients were separated into an acute treatment group (< 30 d from injury to treatment) and a delayed treatment group (> 30 d). Mayo Elbow Performance Scores and postoperative range of motion were collected from patient records. RESULTS: A total of 34 patients were included with a mean follow-up of 42 months. No difference was seen in Mayo Elbow Performance Scores between acute (mean, 90) or delayed treatment (mean, 89) of the lateral ulnar collateral ligament tear. No difference was seen in final elbow flexion or extension. Two patients in the acute group had failure of the direct repair requiring intervention. In the delayed group, no patients had recurrent instability. CONCLUSIONS: No significant difference in clinical outcome or range of motion was observed after direct repair of traumatic tears of the lateral ulnar collateral ligament tear between acute and delayed treatment cohorts. Despite complete disruption of the posterolateral ligaments, direct repair of the torn ligament to its humeral origin was effective without supplemental tendon graft reconstruction irrespective of interval from injury to repair, mechanism of injury, or associated fractures. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic III.

An association can be found between hounsfield units and success of lumbar spine fusion.

BACKGROUND: Measuring Hounsfield units (HUs) from computed tomography (CT) scans has recently been proposed as a tool for assessing vertebral bone quality, as it has been associated with bone mineral density, compressive strength, and fracture risk. Vertebral bone quality is believed to be an important determinant of outcome and complication rates following spine surgery and potentially influences success of interbody spinal fusion. QUESTIONS/PURPOSES: The purpose of this study was to investigate the association between HU on CT scans and fusion success in patients with lateral transpsoas surgery for lumbar interbody fusion (LIF). METHODS: The CT scans of 28 patients with a combined 52 levels of stand-alone LIF were evaluated at a minimum of 12 weeks postoperatively. Coronal and sagittal images were evaluated for evidence of fusion, and HU values were collected from axial images. HU measurements were also taken from vertebral bodies proximal to the construct to evaluate global bone quality. RESULTS: Of the 52 LIF levels, 73% were assessed as fused and 27% were nonunited at the time of evaluation. The successful fusion levels had significantly higher HU measurements than the nonunion levels (203.3 vs. 139.8, p < 0.001). Patients with successful fusion constructs also had higher global bone density when vertebral bodies proximal to the construct were compared (133.7 vs. 107.3, p < 0.05). CONCLUSION: With the aging population and increasing prevalence of osteoporosis, preoperative assessment of bone quality prior to spinal fusion deserves special consideration. We found that a successful lumbar fusion was associated with patients with higher bone density, as assessed with HU, both globally and within the fusion construct, as compared to patients with CT evidence of nonunion.

Magnetic resonance imaging findings in acute elbow dislocation: insight into mechanism.

PURPOSE: To identify with magnetic resonance imaging the location and severity of ligamentous injury after acute elbow dislocations. Based on observations that many elbow dislocations arise from an initial acute valgus load, we hypothesized that all patients would have a high-grade medial injury but not all would demonstrate injury of the lateral ligaments. METHODS: The medial collateral ligament was subdivided into anterior bands of the anterior bundle of the medial collateral ligament (MCL) and posterior bands of the anterior bundle of the MCL, whereas the lateral collateral ligament was divided into the lateral ulnar collateral ligament and the radial collateral ligament. Distinction on magnetic resonance imaging was made between normal morphology and low-grade partial tear (< 50% of the ligament fibers), high-grade partial tear (≥ 50%), and full-thickness disruption. The site of disruption was also characterized. RESULTS: Acute magnetic resonance imaging studies for 16 patients were included. No low-grade tears or intact evaluations of either the anterior or posterior bands of the anterior bundle of the MCL were observed; most demonstrated complete tears. The lateral ulnar collateral ligament most frequently showed complete disruption but was occasionally intact. The radial collateral ligament infrequently showed full disruption. Complete tears involving either the anterior or posterior portions of the anterior band of the MCL were significantly more common than complete tears involving the ligaments on the lateral side. CONCLUSIONS: After elbow dislocation, complete ligamentous tears were more common on the medial versus the lateral side. Whereas the lateral ligaments were occasionally preserved, this was never observed on the medial side. These data suggest a sequence of failure starting on the medial side with subsequent variable energy dissipation laterally. TYPE OF STUDY/LEVEL OF EVIDENCE: Diagnostic IV.