Faculty Bibliography

Restoration of the joint line of the knee during primary and revision total knee arthroplasty is a step that directly influences patient outcomes. In revision total knee arthroplasty, necessary bony landmarks may be missing or obscured, so there remains a lack of consensus on how to accurately identify and restore the joint line of the knee. In this study, 50 magnetic resonance images of normal knees were analyzed to determine a quantitative relationship between the joint line of the knee and 6 bony landmarks: medial and lateral femoral epicondyles, medial and lateral femoral metaphyseal flares, tibial tubercle, and proximal tibio-fibular joint. Wide variability was found in the absolute distance from each landmark to the joint line of the knee, including significant differences between the sexes. Normalization of the absolute distances to femoral or tibial diameters revealed reliable spatial relationships to the joint line of the knee. The joint line was found to be equidistant from the lateral femoral epicondyle and the proximal tibio-fibular joint, representing a reproducible point of reference for joint line restoration. The authors propose a simple 3-step algorithm that can be used with magnetic resonance imaging, computed tomography, or radiography to reliably determine the anatomical location of the joint line of the knee relative to the surrounding bony anatomy. [Orthopedics. 2016; 39(6):381-386.].

BACKGROUND: Considerable debate remains over which anterior cruciate ligament (ACL) reconstruction technique can best restore knee stability. Traditionally, femoral tunnel drilling has been done through a previously drilled tibial tunnel; however, potential nonanatomic tunnel placement can produce a vertical graft, which although it would restore sagittal stability, it would not control rotational stability. To address this, some suggest that the femoral tunnel be created independently of the tibial tunnel through the use of an anteromedial (AM) portal, but whether this results in a more anatomic footprint or in stability comparable to that of the intact contralateral knee still remains controversial. QUESTIONS/PURPOSES: (1) Does the AM technique achieve footprints closer to anatomic than the transtibial (TT) technique? (2) Does the AM technique result in stability equivalent to that of the intact contralateral knee? (3) Are there differences in patient-reported outcomes between the two techniques? METHODS: Twenty male patients who underwent a bone-patellar tendon-bone autograft were recruited for this study, 10 in the TT group and 10 in the AM group. Patients in each group were randomly selected from four surgeons at our institution with both groups demonstrating similar demographics. The type of procedure chosen for each patient was based on the preferred technique of the surgeon. Some surgeons exclusively used the TT technique, whereas other surgeons specifically used the AM technique. Surgeons had no input on which patients were chosen to participate in this study. Mean postoperative time was 13 +/- 2.8 and 15 +/- 3.2 months for the TT and AM groups, respectively. Patients were identified retrospectively as having either the TT or AM Technique from our institutional database. At followup, clinical outcome scores were gathered as well as the footprint placement and knee stability assessed. To assess the footprint placement and knee stability, three-dimensional surface models of the femur, tibia, and ACL were created from MRI scans. The femoral and tibial footprints of the ACL reconstruction as compared with the intact contralateral ACL were determined. In addition, the AP displacement and rotational displacement of the femur were determined. Lastly, as a secondary measurement of stability, KT-1000 measurements were obtained at the followup visit. An a priori sample size calculation indicated that with 2n = 20 patients, we could detect a difference of 1 mm with 80% power at p < 0.05. A Welch two-sample t-test (p < 0.05) was performed to determine differences in the footprint measurements, AP displacement, rotational displacement, and KT-1000 measurements between the TT and AM groups. We further used the confidence interval approach with 90% confidence intervals on the pairwise mean group differences using a Games-Howell post hoc test to assess equivalence between the TT and AM groups for the previously mentioned measures. RESULTS: The AM and TT techniques were the same in terms of footprint except in the distal-proximal location of the femur. The TT for the femoral footprint (DP%D) was 9% +/- 6%, whereas the AM was -1% +/- 13% (p = 0.04). The TT technique resulted in a more proximal footprint and therefore a more vertical graft compared with intact ACL. The AP displacement and rotation between groups were the same and clinical outcomes did not demonstrate a difference. CONCLUSIONS: Although the AM portal drilling may place the femoral footprint in a more anatomic position, clinical stability and outcomes may be similar as long as attempts are made at creating an anatomic position of the graft. LEVEL OF EVIDENCE: Level III, therapeutic study.

BACKGROUND: Duplex ultrasound is routinely used to evaluate suspected deep venous thrombosis after total joint arthroplasty. When there is a clinical suspicion for a pulmonary embolism, a chest angiogram (chest CTA) is concomitantly obtained. QUESTIONS/PURPOSES: Two questions were addressed: First, for the population of patients who receive duplex ultrasound after total joint arthroplasty, what is the rate of positive results? Second, for these patients, how many of these also undergo chest CTA for clinical suspicion of pulmonary embolus and how many of these tests are positive? Furthermore, what is the correlation between duplex ultrasound results and chest CTA results? METHODS: A retrospective chart review was conducted of total joint replacement patients in 2011 at a single institution. Inclusion criteria were adult patients who underwent a postoperative duplex ultrasonography for clinical suspicion of deep venous thrombosis (DVT). Demographic data, result of duplex scan, clinical indications for obtaining the duplex scan, and DVT prophylaxis used were recorded. Additionally, if a chest CTA was obtained for clinical suspicion for pulmonary embolus, results and clinical indication for obtaining the test were recorded. The rate of positive results for duplex ultrasonography and chest CTA was computed and correlated based on clinical indications. RESULTS: Two hundred ninety-five patients underwent duplex ultrasonography of which only 0.7% were positive for a DVT. One hundred three patients underwent a chest CTA for clinical suspicion of a pulmonary embolism (PE) of which 26 revealed a pulmonary embolus, none of which had a positive duplex ultrasound. CONCLUSION: Postoperative duplex scans have a low rate of positive results. A substantial number of patients with negative duplex results subsequently underwent chest CTA for clinical suspicion for which a pulmonary embolus was found, presumably resulting from a DVT despite negative duplex ultrasound result. A negative duplex ultrasonography should not rule out the presence of a DVT which can embolize to the lungs and thus should not preclude further workup when clinical suspicion exists for a pulmonary embolus.

Spinning is a popular indoor stationary cycling program that uses group classes as a motivational tool. Exertional rhabdomyolysis (ER) is frequently reported in athletes and military recruits; however, infrequently it has been reported after spinning class. ER is diagnosed by clinical history, physical exam, and laboratory values. Hydration, electrolyte management, and pain control are key components to treatment of this condition. Severe cases can be complicated by acute renal failure, compartment syndrome, arrhythmia, and disseminated intravascular coagulation. We describe three cases of admission due to rhabdomyolysis after spinning. The diagnosis, admission criteria, and medical treatment of ER are presented in the context of a literature review. A retrospective review of three cases with review of the current literature. The medical and laboratory records of three patient cases were reviewed. A search of the PubMed database was used to perform a comprehensive review of exertional rhabdomyolysis. Our institution's IRB reviewed this study. We report three cases of exertional rhabdomyolysis after spinning and describe the diagnostic workup and medical management of these patients. The diagnosis of ER is made by clinical history, physical exam, and laboratory values. The disease spectrum ranges from mild to severe with the potential of serious complications in some patients. We demonstrate three cases of ER in deconditioned individuals who presented to the emergency department for evaluation. Careful medical management and patient monitoring resulted in improved patient symptomatology and eventual return to physical activity.

Extensor mechanism disruptions are relatively uncommon injuries involving injury to the quadriceps tendon, patella, or patellar tendon. Patellar tendon avulsions from the tibial tubercle in adults are rare; as such, little technical information has been written regarding surgical management of this injury in the adult. Transosseous-equivalent repairs have been described in the management of several types of tendon ruptures, including rotator cuff and distal triceps tendon ruptures, but not previously in patellar injuries. We present a technique for repairing an avulsion injury of the patellar tendon from the tibial tubercle using suture anchors in a transosseous-equivalent manner. This technique for treating distal patellar tendon avulsion injuries likely increases contact area at the repair site while potentially improving fixation strength.

INTRODUCTION: Historically, venous thromboembolism (VTE) in the setting of elective knee arthroscopy has been considered rare. However, more recently, the rate of deep vein thrombosis (DVT) has been reported to be approxi - mately 10%. With increasing recognition of the potential for the development of thromboembolic events, several random - ized trials have evaluated the efficacy of chemoprophylaxis in reducing the risk of VTE following knee arthroscopy. However, all of these studies have evaluated the efficacy of low molecular weight heparins (LMWH), with reductions in the risk of DVT ranging from 65% to 93%, but with the potential side effect of bleeding. At the present time, there have been no randomized studies reported evaluating the utility of aspirin, an agent with a reportedly lower bleeding risk than LMWH, as pharmacologic prophylaxis against VTE after arthroscopic knee surgery. METHODS: In a single-center, randomized, single-blind prospective trial, the efficacy of aspirin as postopera - tive pharmacologic VTE prophylaxis was evaluated in a low risk population undergoing knee arthroscopy. One hundred seventy patients were randomized to a treatment group of 325 mg of aspirin daily for 14 days postoperatively (66 patients) or to the control group with no intervention (104 patients). Bilateral, whole leg, com - pression venous duplex ultrasonography was performed 10 to 14 days postoperatively to document the incidence of DVT. The primary endpoint of the current study was the development of DVT or pulmonary embolism (PE), and the secondary endpoint was the development of a postoperative complication. RESULTS: The study cohort was comprised of 104 males (61%) and 66 females (39%) with a mean age of 44.4 +/- 14.4 years (range: 18 to 75 years). Within both the aspirin treatment and control groups, the surgical procedures in - cluded meniscectomy, ACL reconstruction, chondroplasty, and meniscus repair. No cases of postoperative deep vein thrombosis (DVT) or pulmonary embolism (PE) were identi - fied in either arm of the study during the observation period. Twenty-three patients experienced a complication, including pain or swelling (9%), residual joint line tenderness (3%), arthrofibrosis (0.6%), and instability after a fall (0.6%). Three patients developed knee swelling, two of them in the aspirin group and one of whom required a knee aspiration. However, there was no difference in the development of complications between the two patient populations (p = 0.76, odds ratio [OR] 1.14, 95% confidence interval [CI] 0.5-2.56). CONCLUSIONS: With no cases of VTE identified in our pa - tient population, the use of aspirin in a low-risk population undergoing arthroscopic knee surgery is not warranted.

PURPOSE: To evaluate whether screening radiographs as part of the initial workup of knee pain impacts clinical decision-making in a sports medicine practice. METHODS: A questionnaire was completed by the attending orthopaedic surgeon following the initial office visit for 499 consecutive patients presenting to the sports medicine centre with a chief complaint of knee pain. The questionnaire documented patient age, duration of symptoms, location of knee pain, associated mechanical symptoms, history of trauma within the past 2 weeks, positive findings on plain radiographs, whether magnetic resonance imaging was ordered, and whether plain radiographs impacted the management decisions for the patient. Patients were excluded if they had prior X-rays, history of malignancy, ongoing pregnancy, constitutional symptoms as well as those patients with prior knee surgery or intra-articular infections. Statistical analyses were then performed to determine which factors were more likely do correspond with diagnostic radiographs. RESULTS: Overall, initial screening radiographs did not change management in 72 % of the patients assessed in the office. The mean age of patients in whom radiographs did change management was 57.9 years compared to 37.1 years in those patients where plain radiograph did not change management (p < 0.0001). Plain radiographs had no impact on clinical management in 97.3 % of patients younger than 40. In patients whom radiographs did change management, radiographs were more likely to influence management if patients were over age forty, had pain for over 6 months, had medial or diffuse pain, or had mechanical symptoms. A basic cost analysis revealed that the cost of a clinically useful radiographic series in a patient under 40 years of age was $7,600, in contrast to $413 for a useful series in patients above the age of 40. CONCLUSION: Data from the current study support the hypothesis that for the younger patient population, routine radiographic imaging as a screening tool may be of little clinical benefit. Factors supporting obtaining screening radiographs include age greater than 40, knee pain for greater than 6 months, the presence of medial or diffuse knee pain, and the presence of mechanical symptoms. LEVEL OF EVIDENCE: II.

Purpose: Examine the accuracy of diagnosing adhesive capsulitis (AC) on MRI, using physical exam and clinical impression of an orthopedic sports clinician as the diagnostic reference standard. Materials and Methods: Retrospective query of our digital database was performed to identify all shoulder MRIs performed at our institution in 2013. The first 100 consecutive subjects aged >40 were included for further review. MRI reports were assessed for the presence of the following information: 1. Thickening of the capsule at the axillary recess (AR), 2. Thickening of the coracohumeral ligament (CHL), 3. Infiltration/ edema of subcoracoid fat, 4. Disproportionate fluid within the proximal biceps tendon sheath, and 5. Imaging impression ofAC. Orthopedic notes were assessed for documented range of shoulder motion and overall clinical impression (10 sports fellowship-trained orthopedic surgeons, 1 shoulder and elbow fellowship-trained orthopedic surgeon, and 1 sports medicine trained primary care physician). Sensitivity, specificity, negative predictive value (NPV), positive predictive value (PPV) and overall accuracy were calculated. Fisher exact tests were performed to determine whether each imaging finding was predictive of a positive clinical diagnosis of AC, or likely to predispose to a false positive diagnosis of AC. Results: One hundred shoulder MRI reports in 99 patients were analyzed (59men, 40 women;mean age 58, range 40-87). 17 patients were diagnosed with AC based on imaging findings. Of these patients, frequency of imaging findings included: thickening of the AR (11) or the CHL (8), infiltration of subcoracoid fat (13), and disproportionate fluid in the proximal biceps tendon sheath (3). Six patients had a clinical diagnosis of AC. Fifteen MRIs demonstrated false positive results, while false negative results were seen in 4 cases. The overall sensitivity for theMRI diagnosis of AC was 33.3%with a specificity of 84%. The PPV was 11.8 %,NPV 95.2 %, and overall accuracy 81 %. Fisher exact test P values to determine whether each imaging finding was predictive of a reference standard diagnosis of AC ranged from 0.109 to 1.000. P values to determine whether each imaging finding would lead to a false positive MRI diagnosis were <0.001 for subcoracoid fat infiltration, thickening of the AR, and thickening of the CHL, and p = 1.000 for disproportionate fluid in the biceps tendon sheath. Conclusion: The predictive value of the established MRI findings of adhesive capsulitis may not be as strong as previously shown. Radiologists should be aware of potential imaging over diagnosis and should correlate imaging findings with documented physical exam, when available

Purpose: iBalance high tibial osteotomy, (iHTO, Arthrex Inc, Naples, Florida), is a recently introduced surgical procedure for correction of knee varus malalignment. iHTO, utilizing a polyetheretherketone (PEEK) implant and osteoinductive compounds (OIC), presents challenging post operative radiographs which can easily be misinterpreted as infection. Our purpose is to report, based on review of 24 cases, the previously undescribed to the best of our knowledge, radiographic features of iHTO and its complications. Materials and Methods: Retrospective query of our digital database was performed to identify iHTO cases. The clinical and postsurgical images in all cases with > 1-month follow up imaging were reviewed with attention to 1. Correction of varus malalignment, 2. Healing at the osteotomy site, 3. Changes in the OIC, and 4. Complications. Results: There were 24 iHTOs in 23 patients (17 men, 6 women, ages 21-59, mean 44, median 46), imaged 1 to 29 months post-surgery, with angle of correction, when available, ranging from 5 to 14degree. Immediate post-surgical correction of varus malalignment was seen in 100 % of patients. 100 % depicted oval radiolucencies, at bone PEEK interface simulating erosions and infection. Four, often overlapping, signs of healing were noted: 1. Blurring of bony margins at the osteotomy site, noted within 2 weeks post surgery, 2. Blurring of sharp interface between OIC and host bone, 3. Anterior, posterior and less commonly medial bridging callus, 4. Resorption of OIC, noted as early as 4 months. Complications, seen in 7 cases (29 %), included genu varum recurrence (n = 2), painful exuberant bone formation, (n = 1), and propagation of the osteotomy through the lateral tibial cortex (n = 4). In patients with >6 months follow-up, nonunion and possible infection was seen in 1 patient. 2 patients required total knee arthroplasty due to iHTO failure. Conclusion: iBalance HTO typically depicts oval radiolucencies at the PEEK bone interface not to be mistaken for infection. Familiarity with this features, as well as with other signs of healing, should aid the radiologist in accurate interpretation of post operative films of iHTO patients

PURPOSE: To ascertain whether placing the humeral attachment of the lateral ulnar collateral ligament (LUCL) at the humeral center of rotation (hCOR) on the humerus would provide the most isometric reconstruction. METHODS: We analyzed 13 cadaver limbs from mid-humerus to the hand. The morphology of the ligament complex was assessed. The hCOR was then found using radiographic parameters. We chose 7 points on the humerus located at and around the hCOR and 3 points paralleling the supinator crest of the ulna and then calculated distances from these points using a digital caliper at 0 degrees , 30 degrees , 60 degrees , 90 degrees , and 130 degrees flexion. Differences in potential ligamentous lengths (termed graft elongation) were then calculated and statistical analysis was performed. RESULTS: There was no perfectly isometric point along the humerus or ulna. However, in all specimens the hCOR was the most isometric point for the humeral reconstruction site, with an average graft elongation of 1.1 mm. Differences in humeral tunnel position dramatically affected graft elongation at all 3 ulnar insertions. Overall, ulnar position had a minimal effect on graft elongation. CONCLUSIONS: Although no perfectly isometric points were found, the humeral center of rotation consistently reproduced the most isometry when assessing graft elongation over range of motion. These data may assist surgeons in proper tunnel placement in LUCL reconstruction. CLINICAL RELEVANCE: In LUCL reconstruction, the humeral tunnel should be placed as close as possible to the center of rotation, whereas placement on the ulna is less critical.