Robin N. Kamal

Total wrist arthroplasty.

Abstract Over the past 40 years, total wrist arthroplasty (TWA) has emerged as a cost‐effective treatment option for wrist arthritis. Firstgeneration implant designs have changed tremendously; current devices are designed to enhance wrist stability, provide greater implant longevity, and minimize surgical and postoperative complications. Although arthrodesis remains the standard for surgical management, TWA outcomes demonstrate that the procedure has excellent clinical promise. Additional prospective studies are needed to compare outcomes of wrist arthrodesis with those of TWA with current implants.

In Vivo Kinematics of the Scaphoid, Lunate, Capitate, and Third Metacarpal in Extreme Wrist Flexion and Extension

PURPOSE Insights into the complexity of active in vivo carpal motion have recently been gained using 3-dimensional imaging; however, kinematics during extremes of motion has not been elucidated. The purpose of this study was to determine motion of the carpus during extremes of wrist flexion and extension. METHODS We obtained computed tomography scans of 12 healthy wrists in neutral grip, extreme loaded flexion, and extreme loaded extension. We obtained 3-dimensional bone surfaces and 6-degree-of-freedom kinematics for the radius and carpals. The flexion and extension rotation from neutral grip to extreme flexion and extreme extension of the scaphoid and lunate was expressed as a percentage of capitate flexion and extension and then compared with previous studies of active wrist flexion and extension. We also tested the hypothesis that the capitate and third metacarpal function as a single rigid body. Finally, we used joint space metrics at the radiocarpal and midcarpal joints to describe arthrokinematics. RESULTS In extreme flexion, the scaphoid and lunate flexed 70% and 46% of the amount the capitate flexed, respectively. In extreme extension, the scaphoid extended 74% and the lunate extended 42% of the amount the capitates extended, respectively. The third metacarpal extended 4° farther than the capitate in extreme extension. The joint contact area decreased at the radiocarpal joint during extreme flexion. The radioscaphoid joint contact center moved onto the radial styloid and volar ridge of the radius in extreme flexion from a more proximal and ulnar location in neutral. CONCLUSIONS The contributions of the scaphoid and lunate to capitate rotation were approximately 25% less in extreme extension compared with wrist motion through an active range of motion. More than half the motion of the carpus when the wrist was loaded in extension occurred at the midcarpal joint. CLINICAL RELEVANCE These findings highlight the difference in kinematics of the carpus at the extremes of wrist motion, which occur during activities and injuries, and give insight into the possible etiologies of the scaphoid fractures, interosseous ligament injuries, and carpometacarpal bossing.

Effects on Cytokines and Histology by Treatment with the Ace Inhibitor Captopril and the Antioxidant Retinoic Acid in the Monocrotaline Model of Experimentally Induced Lung Fibrosis

Monocrotaline (MCT), a pyrrolizidine alkaloid extracted from the shrub Crotalaria spectabilis, induces in the lungs of many mammalian species severe hypertension and fibrosis. Previous work with MCT-induced lung disease in rats has shown that some of the steps to progressive fibrosis can be interrupted or decreased by intervention with retinoic acid (RA) or with the angiotensin converting enzyme inhibitor, captopril. This report emphasizes the pathology and cytokines present in lungs of rats in the MCT model of hypertension and fibrosis in 8 treatment groups, six per group: (1) controls, not treated; (2) captopril; (3) RA; (4) combined captopril and RA. Groups 5-8 replicated groups 1-4 and also received MCT subcutaneously. Tissues were harvested at 28 days for histopathology and measurement of cytokines TGFbeta, TNFalpha, interleukin 6, and IFN_. TGFbeta was depressed at 28 days by MCT, an effect reversed by a combination of captopril and RA. RA influences production of an important Th1 cytokine, IFN_, and demonstrated the greatest limitation of MCT-induced TNFalpha. The MCT-induced lung pathology of vasculitis, interstitial pneumonia and fibrosis was limited by captopril. Smooth muscle actin was overexpressed in MCT treated animals receiving RA, an effect reduced with captopril. Overall, the study confirmed the existence of a protective effect for both captopril and RA from MCT-induced lung damage at 30 days. No synergistic or antagonistic activity was observed when the two drugs were administered together. Each of the drugs exerts different and particular effects on serum and tissue levels of various cytokines, suggesting that each drug is efficient at different points of attack in the control of lung fibrosis.

The Use of Near-Infrared Spectrometry for the Diagnosis of Lower-extremity Compartment Syndrome

While intracompartmental pressure monitoring is a widely used diagnostic tool to measure intracompartmental pressures in the setting of compartment syndrome, its invasive nature has prompted the development of noninvasive techniques, such as near-infrared spectrometry. We prospectively assessed the association between tissue oxygen saturation measured by near-infrared spectrometry and compartment pressure measured by intracompartmental pressure monitoring in a cohort of patients with compartment syndrome of the lower extremity. We hypothesized that tissue oxygen saturation measured by near-infrared spectrometry would negatively correlate with intracompartmental pressures. Tissue oxygen saturation was determined for all 4 compartments of the lower extremity in 7 patients using near-infrared spectrometry. All patients subsequently underwent lower-extremity fasciotomies. Mechanism of injury, compartment pressures, blood pressure, near-infrared spectrometry measurement of tissue oxygen saturation, and characteristics of the muscle at the time of fasciotomy were recorded. The strength of the correlations between tissue oxygen saturation and absolute and relative compartment pressures was estimated based on mixed linear (growth) models with repeated observations nested within patients. Our analyses demonstrated no significant relationship between tissue oxygen saturation measured by near-infrared spectrometry and the absolute or relative compartment pressures. This suggests that compartment tissue oxygen saturation measurements by near-infrared spectrometry do not correlate with the diagnosis of compartment syndrome, and that near-infrared spectrometry would not serve as a reliable diagnostic tool.

Salvage of Distal Radius Nonunion With a Dorsal Spanning Distraction Plate

Treatment of nonunion after previous instrumentation of distal radius fractures represents a reconstructive challenge. Resultant osteopenia provides a poor substrate for fixation, often necessitating wrist fusion for salvage. A spanning dorsal distraction plate (bridge plate) can be a useful adjunct to neutralize forces across the wrist, alone or in combination with nonspanning plates to achieve union, salvage wrist function, and avoid wrist arthrodesis in distal radius nonunion.

Quality Measures in Upper Limb Surgery.

BACKGROUND Quality measures are now commonplace and are increasingly tied to financial incentives. We reviewed the existing quality measures that address the upper limb and tested the null hypothesis that structure (capacity to deliver care), process (appropriate care), and outcome (the result of care) measures are equally represented. METHODS We systematically reviewed MEDLINE/PubMed, Embase, Google Scholar, the American Academy of Orthopaedic Surgeons Clinical Practice Guidelines, the National Quality Forum, the Agency for Healthcare Research and Quality, and the Physician Quality Reporting System for quality measures addressing upper limb surgery. Measures were characterized as structure, process, or outcome measures and were categorized according to their developer and their National Strategy for Quality Improvement in Health Care (National Quality Strategy) priority as articulated by the U.S. Department of Health & Human Services. RESULTS We identified 134 quality measures addressing the upper limb: 131 (98%) process and three (2%) outcome measures. The majority of the process measures address the National Quality Strategy priority of effective clinical care (90%), with the remainder addressing communication and care coordination (5%), person and caregiver-centered experience and outcomes (4%), and community/population health (1%). CONCLUSIONS Our review identified opportunities to develop more measures in the structure and outcome domains as well as measures addressing patient and family engagement, public health, safety, care coordination, and efficient use of resources. The most common existing measures-process measures addressing care-might not be the best measures of upper limb surgery quality given the relative lack of evidence for their use in care improvement.

Updates on disaster preparedness and progress in disaster relief.

&NA; Immediately after the January 2010 earthquake in Haiti, many private citizens, governmental and nongovernmental organizations, and medical associations struggled to mount an effective humanitarian aid response. The experiences of these groups have led to changes at their institutions regarding disaster preparedness and response to future events. One of the main challenges in a humanitarian medical response to a disaster is determining when to end response efforts and return responsibility for delivery of medical care back to the host nation. For such a transition to occur, the host nation must have the capacity to deliver medical care. In Haiti, minimal capacity to deliver such care existed before the earthquake, making subsequent transition difficult. If successful, several initiatives proposed to improve disaster response and increase surgical capacity in Haiti could be deployed to other low‐ and middle‐income countries.

Elongation of the Dorsal Carpal Ligaments: A Computational Study of In Vivo Carpal Kinematics

PURPOSE The dorsal radiocarpal (DRC) and dorsal intercarpal (DIC) ligaments play an important role in scapholunate and lunotriquetral stability. The purpose of this study was to compute changes in ligament elongation as a function of wrist position for the DRC and the scaphoid and trapezoidal insertions of the DIC. METHODS We developed a computational model that incorporated a digital dataset of ligament origin and insertions, bone surface models, and in vivo 3-dimensional kinematics (n = 28 wrists), as well as an algorithm for computing ligament fiber path. RESULTS The differences between the maximum length and minimum length of the DRC, DIC scaphoid component, and DIC trapezoidal component over the entire range of motion were 5.1 ± 1.5 mm, 2.7 ± 1.5 mm, and 5.9 ± 2.5 mm, respectively. The DRC elongated as the wrist moved from ulnar extension to radial flexion, and the DIC elongated as the wrist moved from radial deviation to ulnar deviation. CONCLUSIONS The DRC and DIC lengthened in opposing directions during wrist ulnar and radial deviation. Despite complex carpal bone anatomy and kinematics, computed fiber elongations were found to vary linearly with wrist position. Errors between computed values and model predictions were less than 2.0 mm across all subjects and positions. CLINICAL RELEVANCE The relationships between ligament elongation and wrist position should further our understanding of ligament function, provide insight into the potential effects of dorsal wrist incisions on specific wrist ranges of motion, and serve as a basis for modeling of the wrist.

The Effect of the Dorsal Intercarpal Ligament on Lunate Extension After Distal Scaphoid Excision

PURPOSE After a distal scaphoid excision, most wrists develop a mild form of carpal instability-nondissociative with dorsal intercalated segment instability. Substantial dysfunctional malalignment is only occasionally seen. We hypothesized that distal scaphoid excision would lead to carpal instability-nondissociative with dorsal intercalated segment instability in cadavers and that the dorsal intercarpal (DIC) ligament plays a role in preventing such complications. METHODS We used 10 cadaver upper extremities in this experiment. A customized jig was used to load the wrist with 98 N. Motion of the capitate and lunate was monitored using the Fastrak motion tracking system. Five specimens had a distal scaphoid excision first, followed by excision of the DIC ligament, whereas the other 5 specimens first had excision of the DIC ligament and then had a distal scaphoid excision. Rotation of the lunate and capitate was calculated as a sum of the relative motions between each intervention and was compared with its original location before intervention (control) for statistical analysis. RESULTS Distal scaphoid excision and subsequent DIC ligament excision both led to significant lunate extension. DIC ligament excision alone resulted in lunate flexion that was not statistically significant. After DIC ligament excision, distal scaphoid excision led to significant lunate extension. Capitate rotation was minimal in both groups, verifying that the overall wrist position did not change with loading. CONCLUSIONS Distal scaphoid excision leads to significant lunate extension through an imbalance in the force couple between the scaphotrapeziotrapezoidal joint and the triquetrum-hamate joint. The DIC ligament may serve as a secondary stabilizer to the lunocapitate joint and prevent further lunate extension with the wrist in neutral position. CLINICAL RELEVANCE The development of a clinically symptomatic carpal instability-nondissociative with dorsal intercalated segment instability with lunocapitate subluxation after distal scaphoid excision may be due to an incompetent DIC ligament.

Orthopaedic Surgeon Burnout: Diagnosis, Treatment, and Prevention.

Burnout is a syndrome marked by emotional exhaustion, depersonalization, and low job satisfaction. Rates of burnout in orthopaedic surgeons are higher than those in the general population and many other medical subspecialties. Half of all orthopaedic surgeons show symptoms of burnout, with the highest rates reported in residents and orthopaedic department chairpersons. This syndrome is associated with poor outcomes for surgeons, institutions, and patients. Validated instruments exist to objectively diagnose burnout, although family members and colleagues should be aware of early warning signs and risk factors, such as irritability, withdrawal, and failing relationships at work and home. Emerging evidence indicates that mindfulness-based interventions or educational programs combined with meditation may be effective treatment options. Orthopaedic residency programs, departments, and practices should focus on identifying the signs of burnout and implementing prevention and treatment programs that have been shown to mitigate symptoms.