Kalpit N. Shah

Pathophysiology and risk factors for osteonecrosis

Osteonecrosis, also known as avascular necrosis or AVN, is characterized by a stereotypical pattern of cell death and a complex repair process of bone resorption and formation. It is not the necrosis itself but rather the resorptive component of the repair process that results in loss of structural integrity and subchondral fracture. Most likely, a common pathophysiological pathway exists involving compromised subchondral microcirculation. Decreased femoral head blood flow can occur through three mechanisms: vascular interruption by fractures or dislocation, intravascular occlusion from thrombi or embolic fat, or intraosseous extravascular compression from lipocyte hypertrophy or Gaucher cells. In this review, we emphasize etiologic relationships derived mostly from longitudinal cohort studies or meta-analyses whose causal relationships to osteonecrosis can be estimated with confidence. Understanding risk factors and pathophysiology has therapeutic implications since several treatment regimens are available to optimize femoral head circulation, interrupt bone resorption, and preserve the subchondral bone.

Outrigger rod technique for supplemental support of posterior spinal arthrodesis

BACKGROUND CONTEXT Instrumentation failure is a recognized complication after complex spinal reconstruction and deformity correction. Rod fracture (RF) is the most frequent mode of hardware failure in long-segment spinal fusion surgery. This complication can negatively impact the clinical outcome by producing spinal pain, functional compromise, instability, and loss of deformity correction. PURPOSE To describe the outrigger rod surgical technique. STUDY DESIGN Review of literature, case review, and surgical technique description. PATIENT SAMPLE Two clinical cases are presented. OUTCOME MEASURES Rod fracture. METHODS Outrigger rod placement in posterior spinal arthrodesis is performed by supplementing primary spinal rods with outrigger rods attached with cranial and caudal side-by-side connectors providing a more robust construct. RESULTS This technique may be beneficial for preventing RF in patients undergoing surgery for three-column osteotomy for sagittal imbalance; pseudarthrosis surgery with previous hardware failure; transforaminal lumbar interbody cage placement at multiple levels in realignment procedures, long-segment spinal arthrodesis with impaired host fusion potential; long-segment instrumented fusions that span the cervicothoracic, thoracolumbar, or lumbosacral junction; and across spinal segments at high risk for RF (eg, after extensive resection of vertebral elements in the management of metastatic malignancy). CONCLUSIONS The risk of rod failure is substantial in the setting of long-segment spinal arthrodesis and corrective osteotomy. Efforts to increase the mechanical strength of posterior constructs may reduce the occurrence of this complication. The outrigger rod technique increases spinal construct stiffness and may improve the longevity of the construct. This technique should reduce the rate of device failure during maturation of posterior fusion mass and limit the need for supplemental anterior column support.

Biomechanical Analysis of Pedicle Screw Fixation for Thoracolumbar Burst Fractures.

Treatment of unstable thoracolumbar burst fractures remains controversial. Long-segment pedicle screw constructs may be stiffer and impart greater forces on adjacent segments compared with short-segment constructs, which may affect clinical performance and long-term out come. The purpose of this study was to biomechanically evaluate long-segment posterior pedicle screw fixation (LSPF) vs short-segment posterior pedicle screw fixation (SSPF) for unstable burst fractures. Six unembalmed human thoracolumbar spine specimens (T10-L4) were used. Following intact testing, a simulated L1 burst fracture was created and sequentially stabilized using 5.5-mm titanium polyaxial pedicle screws and rods for 4 different constructs: SSPF (1 level above and below), SSPF+L1 (pedicle screw at fractured level), LSPF (2 levels above and below), and LSPF+L1 (pedicle screw at fractured level). Each fixation construct was tested in flexion-extension, lateral bending, and axial rotation; range of motion was also recorded. Two-way repeated-measures analysis of variance was performed to identify differences between treatment groups and functional noninstrumented spine. Short-segment posterior pedicle screw fixation did not achieve stability seen in an intact spine (P<.01), whereas LSPF constructs were significantly stiffer than SSPF constructs and demonstrated more stiffness than an intact spine (P<.01). Pedicle screws at the fracture level did not improve either SSPF or LSPF construct stability (P>.1). Long-segment posterior pedicle screw fixation constructs were not associated with increased adjacent segment motion. Al though the sample size of 6 specimens was small, this study may help guide clinical decisions regarding burst fracture stabilization. [Orthopedics. 2016; 39(3):e514-e518.].

A Biomechanical Evaluation of a 2-Suture Anchor Repair Technique for Thumb Metacarpophalangeal Joint Ulnar Collateral Ligament Injuries

Background: A complete thumb ulnar collateral ligament (UCL) repaired with 1-suture anchor has been demonstrated to be significantly weaker compared with the intact UCL. The objective of this study is to test the biomechanical strength of a 2-anchor thumb UCL repair. Methods: Nine paired fresh-frozen hands were used for this biomechanical analysis. One thumb from each pair was randomized to the control group and one to the repair group. In the control group, the UCL was loaded to failure in tension. In the repair group, the UCL was dissected off of the proximal phalanx, subsequently repaired with a 2-anchor technique, and then tested to failure. Results: The mean yield load was 342 N (95% confidence interval [CI], 215-470 N) in the control group and 68 N (95% CI, 45-91 N) in the repair group. The mean maximum load at failure was 379 N (95% CI, 246-513 N) in the control group and 84 N (95% CI, 62-105 N) in the repair group. The mean stiffness was 72 N/m (95% CI, 48-96 N/m) in the control group and 17 N/m (95% CI, 13-21 N) in the repair group. The mean displacement at failure was 7.8 mm (95% CI, 7-9 mm) in the control group and 7.8 mm (95% CI, 7-9 mm) in the repair group. Conclusions: The 2-anchor repair technique we tested does not acutely reestablish the strength of the insertion of the native insertion of the UCL with this technique.

Tibial Eminence Fracture Repair With Double Hewson Suture Passer Technique

Displaced tibial eminence fractures are commonly encountered in pediatric patients and are often considered to be functionally equivalent to an anterior cruciate ligament (ACL) rupture. While a variety of techniques are available for fixation of this injury, we describe an anchorless technique relying on suture fixation tied over a bone bridge. This technique also relies on two intra-articular Hewson suture passers to quickly and effectively pass and shuttle sutures through the ACL and tibial bone tunnels in order to reduce and fix the fracture fragment. We also briefly review various types of fixation used for tibial eminence fractures.

Total Joint Arthroplasty in Patients with Human Immunodeficiency Virus

With the advent of highly active antiretroviral therapy (HAART), total joint arthroplasty has become a safe and effective procedure for patients infected with the human immunodeficiency virus (HIV).A correlation between a low CD4+ count (<200 cells/mm3) and major postoperative complications such as deep joint infection has been postulated, although high-level studies are not available in the literature.As most studies have not demonstrated an increase in the incidence of deep-vein thrombosis in patients with HIV/AIDS (acquired immunodeficiency syndrome), our recommendation is to use the standard prophylaxis that is followed by the operating surgeon.

Prevention of paralytic ileus utilizing alvimopan following spine surgery

Postoperative ileus affects a substantial proportion of patients undergoing elective spine surgery, especially in cases of spinal deformity correction and where an anterior lumbar approach is utilized. Though the first line of treatment for postoperative ileus is conservative management, recent advances in pharmacology have yielded promising options for both treatment and prevention. We report a case of a patient who underwent a two-stage posterior spinal fusion. The patient suffered with a severe, prolonged ileus after her initial surgery. To prevent ileus following her second spinal surgery, alvimopan (a µ-opioid receptor antagonist) was administered and she had a rapid return of bowel function with no signs of ileus. Alvimopan, has been shown to reduce the rate of ileus in colorectal surgery patients, and may be useful for preventing ileus in high-risk orthopedic and spine surgery patients, although prospective studies will be needed to test this hypothesis.

Effect of Narcotic Prescription Limiting Legislation on Opioid Utilization Following Lumbar Spine Surgery

BACKGROUND CONTEXT Prescription opioid abuse is a public health emergency. Opioid prescriptions for spine patients account for a large proportion of use. Some states have implemented statutory limits on prescribers, however it remains unclear whether such laws are effective. PURPOSE This investigation compares opioid prescription patterns for patients undergoing lumbar spine surgery before and after the passage of statewide narcotic-limiting legislation in Rhode Island. STUDY DESIGN/SETTING Retrospective review of prospectively-collected medical and pharmacologic data. PATIENT SAMPLE Two patient cohorts (pre-law January 1, 2016-June 31, 2016 and post-law June 1, 2017-December 31, 2017) that included all patients undergoing selected lumbar spine surgeries (lumbar discectomy, lumbar decompression without fusion, and posterior lumbar fusion). METHODS Demographic and surgical variables were collected from the patients medical charts, and information on controlled substances was collected from the state prescription drug monitoring program database. Variables collected included the number of pills and total morphine milligram equivalents (MMEs) of the first prescription, number of prescriptions filled within 30 days of surgery, total MMEs filled in the 30-day postoperative period, and total MMEs filled from 30 to 90 days after surgery. For comparison of continuous variables, t test or Mann-Whitney U test were used as appropriate. Chi-squared analysis was utilized for comparison of categorical variables. Independent risk factors for prolonged postoperative opioid use were evaluated using logistic regression. RESULTS There were no significant differences between pre-law (n = 241) and post-law (n = 311) cohorts in terms of age, sex, preoperative opioid use, or preoperative anxiolytic use (p > .05). A greater than 50% decline was observed among all patients from the pre-law to the post-law period in terms of the number of pills (51.61 vs 23.60 pills, p < .001) and MMEs (525.56 vs 218.77 MMEs, p < .001) provided in the first postoperative opioid prescription. The mean total MMEs provided in the first 30 days decreased significantly (891.26 vs 628.63 MMEs, p < .001) despite an increase in the average number of opioid prescriptions filled (1.75 vs 2.04 prescriptions, p = .002) during this time. There was no significant difference in mean MMEs filled from 30 to 90 days. Upon subgroup analysis, there was a statistically significant decline in both the mean first prescription and total 30-day MMEs regardless of preoperative opioid status (all p < .05) or specific procedure performed (all p < .05). Preoperative opioid use was strongly associated with prolonged postoperative opioid requirements throughout the study period (OR 4.71, 95% CI 3.11-7.13, p < .001). There were no significant differences between cohorts in terms of emergency department (ED) visits or unplanned hospital readmissions at 30 and 90 days following surgery (all p > .05). CONCLUSIONS The institution of mandatory statewide opioid prescription limits has resulted in a significant reduction in initial and 30-day opioid prescriptions following lumbar spine surgery. Decreased opioid utilization was observed in all patients, regardless of preoperative opioid tolerance or procedure performed. No significant change in postoperative ED visits or unplanned hospital readmissions was seen following implementation of the legislation. This investigation provides preliminary evidence that narcotic limiting legislation may be effective in decreasing opioid prescriptions after lumbar spine surgery for both opioid-naïve and opioid-tolerant patients.

Trends in research productivity of residents applying for orthopedic sports medicine fellowship

ABSTRACT Objectives: Though there are no research requirements to match into an orthopaedic sports medicine fellowship, many applicants are productive in research endeavors during residency. We hypothesize that the number of publications by Orthopaedic sports medicine applicants are increasing. Methods: A list of current and recent sports medicine fellows was compiled from publicly accessible information on sports medicine fellowship websites. Articles published while the fellow was a resident were identified via publicly available search engines. The following information was collected: year of fellowship and years of residency, fellowship program, geographic location of fellowship program, total number of publications (noting specifically first and last author publications), number of publications in high impact orthopaedic journals (AJSM, JBJS Am, JSES, or Arthroscopy). Results: Overall, 189 fellowship-matched surgeons from 2010 – 2017 were identified. There were 746 publications (average of 3.95 per fellow), with 218 (29.2%) in high impact orthopaedic journals. Surgeons who completed their fellowship during the 2016–17 academic year, published on average 5.42 publications per fellow. Fellowship applicants in the Northeast region had the highest number of total publications (359 publications, 48.1% of all publications; 6.41 publications per fellow). Applicants were listed most often as middle authors (462 publications, 61.9%). Conclusions: There has been an overall increase in the number of publications among sports medicine fellowship applicants in the last several academic years. Fellowship programs in the northeast United States tended to match applicants with a higher number of publications.

Epidemiology of fishing related upper extremity injuries presenting to the emergency department in the United States

ABSTRACT Objective: Fishing injuries commonly affect the hands. The goal of this study was to quantify the incidence of fishing-related upper extremity injuries that present to emergency departments in the United States. Methods: We examined the reported cases of fishing-related upper extremity injuries in the National Electronic Injury Surveillance System database. Analysis was performed based on age, sex and the type of injury reported. Results: The national incidence of fishing-related upper extremity injuries was 119.6 per 1 million person-years in 2014. The most common anatomic site for injury was the finger (63.3%), followed by the hand (20.3%). The most common type of injury in the upper extremity was the presence of a foreign body (70.4%). The incidence of fishing-related upper extremity injuries in males was 200 per 1 million person-years, which was significantly higher than the incidence in females (41 per 1 million person-years). Conclusion: The incidence of fishing-related upper extremity injuries that present to the Emergency Department was 120 per 1 million person-years. The incidence was significantly higher in males. With the widespread popularity of the activity, it is important for Emergency Physicians and Hand Surgeons to understand how to properly evaluate and manage these injuries.