Christopher Kweon

Amphotericin B Delivery From Bone Cement Increases With Porosity but Strength Decreases

BackgroundAmphotericin B is a highly hydrophobic antifungal used for orthopaedic infections. There is disagreement about whether amphotericin B is released when it is loaded in polymethylmethacrylate (PMMA). It is unknown how much a poragen will increase amphotericin B release or decrease the compressive strength of the PMMA.Questions/purposesWe therefore measured amphotericin B release and the compressive strength of amphotericin B loaded bone cement with and without adding high-dose poragen.MethodsAntifungal-loaded bone cement was formulated with Simplex P cement and 200 mg amphotericin B with and without 10 g cefazolin (poragen) per batch. Twenty standardized test cylinders were eluted in deionized water for each formulation. Cumulative amphotericin B mass and compressive strength were measured. Data were analyzed using repeated-measures analysis of variance.ResultsAntifungal-loaded bone cement (ALBC) with 10 g poragen delivered more amphotericin B than ALBC containing amphotericin B alone by Day 15, 12.76 μg/cylinder (0.5%) versus 1.74 μg/cylinder (0.04%), respectively. With amphotericin B alone, compressive strength was unchanged and compressive strength did not decrease during elution. Adding 10 g poragen to ALBC with 200 mg amphotericin B decreased the compressive strength and compressive strength decreased further during elution, 80, 61, and 46 MPa at 0, 1, and 30 days, respectively.ConclusionsAmphotericin B is released in very small amounts from antifungal-loaded bone cement. Release can be increased by adding high-dose poragen, but compressive strength decreases sufficiently to limit its use for implant fixation.

High Satisfaction Yet Decreased Activity 4 Years After Transphyseal ACL Reconstruction

BackgroundACL injuries in preteens and teens are common occurrences. Reconstruction is believed to be optimum treatment for those wishing to return to running, cutting, and jumping sports. Rates of reoperation, satisfaction, and long-term return to and maintenance of preinjury activity after ACL reconstruction in young athletes are important information for physicians, patients, and parents.Questions/purposesThe purposes of this study were to address the following questions in this skeletally immature patient population undergoing ACL reconstruction: (1) What is the reinjury rate and the need for subsequent surgeries? (2) How do patient satisfaction and function as assessed by patient and physician correlate with return to sport? (3) What factors contribute to failure to return to preinjury activity levels?MethodsThis is a retrospective review of 29 patients who underwent transphyseal ACL reconstruction using soft tissue grafts passed through open physes and followed to skeletal maturity, and at least 2 years from their index surgery, who were invited and returned for a study interview and examination. Pre- and postinjury activity levels were assessed via the Tegner activity score, satisfaction was determined using a 10-point Likert scale, function was assessed via the Lysholm score and IKDC grade, and an open-ended questionnaire was used for explanations of changes in activity levels. Reoperations were classified as major or minor, determined from a review of the medical records conducted after interview and examination.ResultsAt a minimum followup of 2 years (mean, 4 years; range, 2–8 years), four revision reconstructions and seven minor operations were performed for a reoperation rate of 11 of 29 (38%). Eight of 29 patients (28%) sustained contralateral ACL ruptures. The mean satisfaction score was 9 (range, 4–10) and mean Lysholm score was 91 (range, 61–100). Only 12 of 29 (41%) patients returned to and maintained their preinjury level of sport. High satisfaction correlated with return to prior level of sports, although there was no relationship between function and activity level. Reoperation on the index knee or contralateral ACL tear did not correlate with a change in activity level; rather, most patients who were less active indicated a change in interest with advancing age.ConclusionsDespite high satisfaction and function, less than 50% of patients maintained their preinjury level of play 4 years after ACL reconstruction. Satisfaction correlated significantly with knee function; highly satisfied patients were more likely to return to and maintain their prior level of participation in sports. Contributing factors to decreased activity include changes in lifestyle with increasing age. Reoperation did not correlate with lower activity scores or failure to return to sports.Level of EvidenceLevel IV, therapeutic study. See the Instructions for Authors for a complete description of levels of evidence.

Anatomy and Biomechanics of the Cruciate Ligaments and Their Surgical Implications

Multiple ligament knee injuries, although rare, are severe injuries because they result in the loss of the passive and active knee stabilizers as well as often being associated with the compromise of neurovascular structures. Treatment of these injuries is controversial, and results after surgery can sometimes be poor. After sustaining injuries to multiple ligaments, the knee is at a biomechanical disadvantage which poses a reconstructive and rehabilitative challenge to even the most experienced orthopedic surgeon. Surgeons performing reconstructions in patients with these injuries must have a complete understanding of the normal anatomy and biomechanics of the knee to optimize the timing of surgery, surgical approach, tunnel preparation, and the anatomic placement of grafts. This chapter outlines the anatomy and biomechanics of the cruciate ligaments and their surgical implications. The structure and form of the anterior and posterior cruciate ligaments, patterns of injury, structural properties of the cruciate ligaments and graft substitutes, functional biomechanics and interplay between the cruciate ligaments, and the surgical implications related to anatomic reconstruction of the anterior and posterior cruciate ligaments are all reviewed in detail.

Arthroscopic Treatment of Cam-Type Impingement of the Hip.

» Six radiographic views of the hip (anteroposterior and false-profile radiographs of the pelvis, cross-table and frog-leg lateral radiographs of the proximal part of the femur, and 45° and 90° Dunn lateral radiographs of the hip) should be made for accurate characterization of cam morphology for preoperative planning and can be repeated intraoperatively for the assessment of correction. Computed tomography (CT) scans, including three-dimensional reconstructions, can provide valuable information for preoperative planning.

Surgical versus Non-surgical Management of Rotator Cuff Tears: Predictors of Treatment Allocation

Objectives: Rotator cuff tears are a common shoulder disorder resulting in significant disability to patients and strain on the health care system. While both surgical and non-surgical management are accepted treatment options, little data exist to guide the surgeon in treatment allocation. Defining variables to guide treatment allocation may be important for patient education and counseling, as well as to deliver the most efficient care plan at the time of presentation. The objective of this study was to identify patient characteristics at the time of initial clinical presentation that are associated with allocation to surgical versus non-surgical management for patients with known full-thickness rotator cuff tears. Methods: 185 consecutive adult patients with known full-thickness rotator cuff tears were enrolled into a prospective cohort study. Robust data were collected for each subject at baseline, including age, gender, body mass index (BMI), shoulder activity score, smoking status, size of cuff tear, duration of symptoms, functional comorbidity index, treating surgeon, the American Shoulder and Elbow Society (ASES) score, the Western Ontario Rotator Cuff Index (WORC), and the Veterans Rand 12 Item Health Survey (VR-12). Logistic regression was performed in order to identity variables associated with treatment allocation, and the corresponding odds ratios were calculated. Results: Of the 185 subject enrolled, 100 underwent surgical intervention and 85 non-operative management. While controlling for co-variates, significant baseline patient characteristics predictive of eventual allocation to surgical treatment included the following: non-smoking status [OR .039 (0.005, 0.300) p=0.002], lower functional comorbidity index [OR 0.739 (0.518, 1.055) p=0.096], younger age [OR 0.872 (0.820, 0.927) p<0.001], lower BMI [OR 0.895 (0.826, 0.970) p=0.007], and symptoms present for fewer than 4 months [OR 3.258 (1.070, 9.921) p=0.038]. Factors that were not associated with treatment allocation included gender, tear size, diabetes, treating surgeon, or any of the patient derived outcome scores at presentation (ASES, WORC, VR-12, shoulder activity score). Conclusion: This prospective cohort study suggests that the factors predictive of treatment allocation are related more to patient demographics at presentation than patient derived outcome scores or intrinsic characteristics of the rotator cuff such as tear size. Further study is warranted to help define appropriate indications for treatment allocation in patients with rotator cuff tears.

Late Mycobacterium tuberculosis infection in the shoulder of an immunocompromised host after hemiarthroplasty: a case report.

Mycobacterium tuberculosis infection of the shoulder is an unusual condition, with few cases reported in the orthopaedic literature. Although skeletal tuberculosis is uncommon in developed countries, several conditions, of which the orthopaedic surgeon should be aware, predispose patients to mycobacterial shoulder infections. We report a case of Mycobacterium tuberculosis infection of the shoulder that occurred thirty-seven years after a shoulder hemiarthroplasty. The patient was informed that data concerning the case would be submitted for publication, and he consented. A seventy-four-year-old man who had a history of left-shoulder posttraumatic arthritis that had been treated thirty-seven years previously with a Neer hemiarthroplasty presented with left shoulder pain, swelling, and induration along with intermittent fever. The medical history was notable for the diagnosis of a gastrointestinal stromal tumor that required multiple debulking resections of the small bowel and liver along with resections of retroperitoneal and subdiaphragmatic metastatic lesions. The patient was undergoing long-term chemotherapy with Sutent (sunitinib malate) for the treatment of extensive metastasis to the liver. At initial presentation, the patient reported that his left shoulder had functioned well except for mild pain and limitations with repetitive overhead activity. His shoulder symptoms had worsened over the preceding three weeks. Physical examination demonstrated intact shoulder motor function along with erythema and fullness in a painful left shoulder. The rotator cuff was intact. Radiographs of the left shoulder revealed a well-aligned hemiarthroplasty without evidence of implant loosening but with moderate glenoid erosion. Magnetic resonance imaging (MRI) and computed tomography (CT) scan of the shoulder were not acquired, but a CT scan of the chest, abdomen, and pelvis acquired two months earlier for surveillance of known gastrointestinal stromal tumor demonstrated mild to moderate glenoid erosion. During his initial hospitalization, the patient underwent two irrigation and debridement procedures of the left shoulder for a suspected abscess. …

Anterior Cruciate Ligament Reconstruction with Hamstring Tendon Autografts and Endobutton Femoral Fixation

The efficacy of ACL reconstruction procedures to improve function in symptomatic ACL-insufficient knees has been well established. Initial satisfactory results utilizing patellar tendon autografts were compromised to varying extent by harvest site morbidity. In an attempt to reduce harvest site morbidity, other autogenous graft sources have been used as ACL substitutes. Several studies now exist comparing results of ACL reconstruction with quadrupled hamstring grafts and patellar tendon grafts and show no significant subjective differences. Successful reconstruction utilizing any appropriate graft is dependent on the adherence to principles and details of graft harvest and preparation, tunnel placement, fixation, and rehabilitation. In this article, the technique specific to ACL reconstruction with double semitendinosus and gracilis tendons utilizing Endobutton femoral fixation is discussed as well as potential complications of the procedure.

Letter to the Editor: Editorial

To the Editors, We read with interest the recent thoughtful editorial from Leopold and colleagues [1]. If the recommendation of the editors—that orthopaedic surgeons should not be present on the sidelines—was made to bring more focus on an aspect of sports medicine and society that clearly needs more attention, we hope the editors succeed. If the recommendation was made because the editors actually want orthopaedic surgeons to refrain frommedical coverage of football games, the decision marks a deviation of the editorial board’s typical consideration of best evidence as well as important contextual and practical information to make recommendations that represent the ideals of our profession. While chronic traumatic encephalopathy (CTE) is a condition that has garnered significant attention within medicine, as well as in the media over the last 5 years, we still do not fully understand its pathophysiology, causes, and clinical manifestations. Studies demonstrate associations between playing football and having pathologic or clinical signs of CTE, and we do not doubt that these associations are real [2, 3]. However, the relationships between playing football, sustaining concussions, the development of pathologic evidence of CTE, and the development of clinical signs of mental illness are still uncertain. The editors acknowledge that the effect that orthopaedic surgeons’ recusal from football team coverage might achieve may be limited, but that the professional obligation to these atrisk players is more important [1]. If we feel that driving under the influence of alcohol is a risky activity, more dangerous than football with clearer associations and immediate consequences [4, 5], would our professional obligation be to stop attending social events where alcohol is served in order to demonstrate that we do not support this activity because of its potential consequences? We believe that our influence as orthopaedic surgeons is

Late Mycobacterium tuberculosis Infection in the Shoulder of an Immunocompromised Host After Hemiarthroplasty

Mycobacterium tuberculosis infection of the shoulder is an unusual condition, with few cases reported in the orthopaedic literature. Although skeletal tuberculosis is uncommon in developed countries, several conditions, of which the orthopaedic surgeon should be aware, predispose patients to mycobacterial shoulder infections. We report a case of Mycobacterium tuberculosis infection of the shoulder that occurred thirty-seven years after a shoulder hemiarthroplasty. The patient was informed that data concerning the case would be submitted for publication, and he consented. A seventy-four-year-old man who had a history of left-shoulder posttraumatic arthritis that had been treated thirty-seven years previously with a Neer hemiarthroplasty presented with left shoulder pain, swelling, and induration along with intermittent fever. The medical history was notable for the diagnosis of a gastrointestinal stromal tumor that required multiple debulking resections of the small bowel and liver along with resections of retroperitoneal and subdiaphragmatic metastatic lesions. The patient was undergoing long-term chemotherapy with Sutent (sunitinib malate) for the treatment of extensive metastasis to the liver. At initial presentation, the patient reported that his left shoulder had functioned well except for mild pain and limitations with repetitive overhead activity. His shoulder symptoms had worsened over the preceding three weeks. Physical examination demonstrated intact shoulder motor function along with erythema and fullness in a painful left shoulder. The rotator cuff was intact. Radiographs of the left shoulder revealed a well-aligned hemiarthroplasty without evidence of implant loosening but with moderate glenoid erosion. Magnetic resonance imaging (MRI) and computed tomography (CT) scan of the shoulder were not acquired, but a CT scan of the chest, abdomen, and pelvis acquired two months earlier for surveillance of known gastrointestinal stromal tumor demonstrated mild to moderate glenoid erosion. During his initial hospitalization, the patient underwent two irrigation and debridement procedures of the left shoulder for a suspected abscess. …

Late : A Case Report mycobacterium tuberculosis : A Case Report Infection in the Shoulder of an Immunocompromised Host After Hemiarthroplasty: A Case Report

Mycobacterium tuberculosis infection of the shoulder is an unusual condition, with few cases reported in the orthopaedic literature. Although skeletal tuberculosis is uncommon in developed countries, several conditions, of which the orthopaedic surgeon should be aware, predispose patients to mycobacterial shoulder infections. We report a case of Mycobacterium tuberculosis infection of the shoulder that occurred thirty-seven years after a shoulder hemiarthroplasty. The patient was informed that data concerning the case would be submitted for publication, and he consented. A seventy-four-year-old man who had a history of left-shoulder posttraumatic arthritis that had been treated thirty-seven years previously with a Neer hemiarthroplasty presented with left shoulder pain, swelling, and induration along with intermittent fever. The medical history was notable for the diagnosis of a gastrointestinal stromal tumor that required multiple debulking resections of the small bowel and liver along with resections of retroperitoneal and subdiaphragmatic metastatic lesions. The patient was undergoing long-term chemotherapy with Sutent (sunitinib malate) for the treatment of extensive metastasis to the liver. At initial presentation, the patient reported that his left shoulder had functioned well except for mild pain and limitations with repetitive overhead activity. His shoulder symptoms had worsened over the preceding three weeks. Physical examination demonstrated intact shoulder motor function along with erythema and fullness in a painful left shoulder. The rotator cuff was intact. Radiographs of the left shoulder revealed a well-aligned hemiarthroplasty without evidence of implant loosening but with moderate glenoid erosion. Magnetic resonance imaging (MRI) and computed tomography (CT) scan of the shoulder were not acquired, but a CT scan of the chest, abdomen, and pelvis acquired two months earlier for surveillance of known gastrointestinal stromal tumor demonstrated mild to moderate glenoid erosion. During his initial hospitalization, the patient underwent two irrigation and debridement procedures of the left shoulder for a suspected abscess. …