Robert H. Ablove

Morphologic changes following endoscopic and two-portal subcutaneous carpal tunnel release.

This study describes the morphologic changes that occur following single incision endoscopic and two-portal subcutaneous carpal tunnel release. Seventeen patients were studied preoperatively and an average of 24 weeks postoperatively. Canal volume, carpal arch width, and median nerve palmar displacement and cross-sectional area were measured by use of multiplanar reformation and three-dimensional reconstruction of magnetic resonance images. Both methods produced a marked increase in canal volume and median nerve cross-sectional area; neither resulted in a significant change in carpal arch width. These data provide a morphologic basis for the belief that endoscopic or subcutaneous carpal tunnel release will produce clinical relief equivalent to open carpal tunnel release.

Pressure changes in Guyon's canal after carpal tunnel release

We measured pressure changes in Guyons canal and the carpal tunnel before and after endoscopic (11 cases) and open (10) carpal tunnel release. We found that release of the flexor retinaculum by endoscopic and open techniques measurably decreased pressure in both the carpal tunnel and Guyons canal. This study provides an explanation for relief of ulnar tunnel syndrome symptoms following carpal tunnel release and may indicate that carpal tunnel release alone may be sufficient to provide symptomatic relief for most patients with carpal and ulnar tunnel syndromes.

Ultrasound Imaging of Normal Displacement of the Extensor Carpi Ulnaris Tendon Within the Ulnar Groove in 12 Forearm-Wrist Positions

OBJECTIVE Instability of the extensor carpi ulnaris (ECU) tendon can be a difficult clinical diagnosis because of normal changes in tendon position during wrist motion. Our goal was to determine the normal variation of ECU tendon displacement in 12 forearm-wrist positions. SUBJECTS AND METHODS Ultrasound imaging of the ECU tendons of 40 symptom-free wrists of healthy volunteers (13 women, seven men; mean age, 22.3 years; range, 20-25 years) was performed. Each ECU tendon was examined in 12 positions: four wrist positions (ulnar deviation, radial deviation, flexion, and extension) in each of three forearm positions (pronation, supination, and neutral). RESULTS ECU tendon displacement in the right hand was not significantly different from that in the left, and displacement in men did not differ significantly from that in women. There was a small but significant difference between displacement in the dominant and that in the nondominant hand (p < 0.02). Mean ECU tendon displacement was greatest in the supinated forearm position (p < 0.001) followed by the neutral position (p < 0.001) and was least in the pronated position (p < 0.001). Both ulnar deviation (p < 0.001) and flexion (p < 0.002) were associated with greater ECU tendon displacement than were radial deviation (p < 0.001) and extension (p < 0.002). Maximum percentage displacement volar to the ulnar border of the groove was 50% in flexed supination and ulnar deviation. The maximum displaced distance volar to the ulnar border of the groove was 5 mm. CONCLUSION Sonographic evaluation of the ECU tendon is simple and practical. Knowledge of normal ECU displacement relative to the ulnar groove may help in evaluation of ulnar-sided wrist pain.

Coronoid Fractures of the Elbow

Coronoid fractures of the ulna are relatively uncommon, yet critical injuries to recognize. They often occur in association with elbow dislocations and play an important role in elbow instability. Historic recommendations are to fix all large coronoid fracture fragments, as well as small fracture fragments associated with instability. There is little data regarding management of small coronoid fracture fragments. The coronoid process acts as a bony buttress to prevent posterior dislocation and has three soft tissue insertions which lend stability as well: the anterior joint capsule of the elbow, the brachialis muscle and the medial ulnar collateral ligament. Injured patients often present with swelling, tenderness and limited range of motion. After obtaining a detailed history and performing a careful physical examination, plain radiographs should be obtained. If present, dislocations are reduced and post-reduction stability is assessed. If the elbow is unstable, management usually consists of a combination of bony and soft-tissue repairs often including coronoid process repair. Loss of motion is the most common complication of these injuries. The current recommendation is to repair virtually all coronoid fractures associated with instability.

Distal Biceps Tendon Ruptures An Epidemiological Analysis Using a Large Population Database

Background: The incidence of distal biceps tendon ruptures was studied more than 10 years ago in a small patient cohort. Recent diagnostic advancements have improved the ability to detect this rare injury. Hypothesis: The incidence of distal biceps tendon ruptures will be significantly greater than previously reported. Study Design: Descriptive epidemiologic study. Methods: A query of the PearlDiver Technologies national database containing public and private insurance patients was used to estimate the national incidence of distal biceps tendon ruptures in the United States. A retrospective chart review of our local population identified demographic groups and risk factors that increased likelihood of injury. Results: The estimated national incidence of distal biceps tendon rupture was 2.55 per 100,000 patient-years. The local incidence was 5.35 per 100,000 patient-years. The mean and median ages of patients in our regional cohort were 46.3 and 46 years, respectively. Males composed the majority of the injured population (national 95%, regional 96%). Smoking and elevated body mass index were found to be associated with increased likelihood of injury, while diabetes mellitus showed no association. Conclusion: The incidence of distal biceps tendon ruptures in this study was higher than previously reported.

Ulnar coronoid process anatomy : Possible implications for elbow instability

Ulnar coronoid process fractures are relatively uncommon injuries usually occurring with elbow dislocations and contributing to elbow instability. Recent evidence suggests coronoid tip fractures have a role in the instability. We sought to quantify the capsular and brachialis attachments of the ulnar coronoid process to better understand why instability occurs. We prepared eight fresh-frozen cadaveric specimens to ascertain the specific attachment locations. After dissection, we isolated and resected the proximal ulna, including the coronoid process and its soft tissue attachments. We then embedded, sectioned, and stained the specimens. The average distance from the tip of the coronoid to the proximal capsule was 2.36 ± 0.39 mm. The average distance from the tip of the coronoid to the proximal brachialis insertion was10.13 ± 1.6 mm. Most coronoid tip fractures included disruption of the anterior capsule, which potentially explains why instability can be associated with these fractures.

Effect of high-energy phosphates and free radical scavengers on replant survival in an ischemic extremity model

In replantation surgery, preoperative and intraoperative ischemia can lead to irreversible changes that prevent reperfusion during the subsequent re‐establishment of circulation. These changes are termed the no‐reflow phenomenon. Ischemic phase damage was addressed by comparing the dose‐response effects of controls vs. five different high‐energy phosphate compounds on replanted limb survival. Reperfusion damage was evaluated via comparisons of controls with superoxide dismutase (SOD). Ischemic hindlimbs treated with high‐energy phosphates displayed improved survival compared with controls. Limbs treated with SOD demonstrated no change in survival at 4 hours and improved survival at 8 hours. Combining adenosine and SOD had no improved effect on survival. Adenosine was the most effective high‐energy phosphate in limiting ischemic damage. The free radical scavenger (SOD) was beneficial only at the later stages of ischemia. In this experimental model, there appears to be a role for both phosphates and free radical scavengers in enhancing ischemic tissue survival

Body mass index continues to accurately predict percent body fat as women age despite changes in muscle mass and height.

ObjectiveBody mass index (BMI) is commonly used to predict obesity in clinical practice because it is suggested to closely correlate with percent body fat (%BF). With aging, women lose both lean mass and height. Because of this, many clinicians question whether BMI is an accurate predictor of obesity in aging women. In evaluating the equation for BMI (weight/height2), it is clear that both variables can have a dramatic effect on BMI calculation. We evaluated the relationship between BMI and %BF, as measured by dual-energy x-ray absorptiometry, in the setting of age-related changes in height loss and body composition in women. Our objective is to determine whether BMI continues to correlate with %BF as women age. MethodsStudy participants were identified using data from five osteoporosis clinical trials, where healthy participants had full-body dual-energy x-ray absorptiometry scans. Deidentified data from 274 women aged between 35 and 95 years were evaluated. %BF, weight, age, tallest height, actual height, and appendicular lean mass were collected from all participants. BMI was calculated using the actual height and the tallest height of each study participant. %BF was compared with BMI and stratified for age. ResultsBMI calculated using the tallest height and BMI calculated using actual height both had strong correlations with %BF. ConclusionsSurprisingly, the effects of changes in height and lean body mass balance each other out in BMI calculation. There continues to be a strong correlation between BMI and %BF in adult women as they age.

The effect of metacarpal shortening on digital flexion force

Metacarpal shaft fractures are common injuries that frequently unite with some shortening of the metacarpal. The aim of this study was to determine the effect of metacarpal shortening on digital flexion force. The index metacarpal of six cadaveric upper limbs was incrementally shortened. The flexion force produced at the end of the finger was recorded using a small load cell. At full extension, there was no significant change in flexion force produced regardless of the amount of shortening. However, at 50% aggregate flexion the loss of force became statistically significant at a shortening of 7.5 mm or more. At full digital flexion, the loss of force became statistically significant at shortening of 5 mm or more. At increasing amounts of finger flexion, progressive metacarpal shortening produces proportionally greater loss of fingertip flexion force. From this study it appears that metacarpal shortening of up to 5 mm should give minimal loss of finger flexion force.

Elevation in compartment pressure following hypovolemic shock and fluid resuscitation: a canine model.

We induced hemorrhagic shock in seven dogs and then resuscitated them with intravenous (IV) lactated ringers. We then monitored anterior leg compartment pressures via a slit catheter during both bleeding and reperfusion. These values were compared with controls that received IV fluids without being bled. Compartment pressures in resuscitated dogs rose well above control values. These values were statistically significant when compared to controls via the paired student t test (P < .01). This model demonstrates that sufficient swelling occurs to significantly elevate compartment pressures, even in the absence of local trauma. While this elevation may not be sufficient enough to cause a compartment syndrome, it reinforces the notion that extremities that have experienced ischemia and reperfusion are at an increased risk for developing compartment syndrome.