Kirk A. Campbell

Analysis of the Cross-Sectional Area of the Adductor Longus Tendon A Descriptive Anatomic Study

Background Strain injury to the adductor longus muscle is a common cause of groin pain in athletes and generally occurs in the proximal portion of the muscle, near its origin from the anterior aspect of the pubis. The composition and cross-sectional anatomy of this muscles origin has not been previously described. Hypothesis We hypothesize that the adductor longus muscle origin is composed mainly of muscle fibers and that the tendon composes only a small part of the cross section at the origin of the muscle. Study Design Descriptive laboratory study. Methods We harvested 42 adductor longus muscles from 28 cadavers and measured the cross-sectional dimensions of the tendon with microcalipers. Next, we determined the relative contributions of the tendon and muscle fibers to the cross-sectional anatomy of the muscle using optical scanning. These 2 sets of measurements were obtained at 3 locations: at the muscle origin and 1.0 and 2.0 cm distal to the origin. Results The average length and width of the tendon was 11.6 and 3.7 mm, respectively, at the origin. The average cross-sectional areas of the tendon were 49.3, 27.9, and 25.7 mm2 at points 0.0, 1.0, and 2.0 cm from its origin, respectively. The origin of the adductor longus muscle was composed of 37.9% tendon and 62.1% muscle tissue. At 1.0 cm from the origin, the percentage of tendon decreased to 34%. At 2.0 cm from the origin, the tendon composed 26.7% of the cross section. Conclusion The cross-sectional area of the tendon of the adductor longus muscle is relatively small. The muscle origin is composed predominantly of direct attachment of muscle fibers. Clinical Relevance Knowledge of the cross-sectional anatomy of the adductor longus muscle at its origin may help clinicians better understand the complex nature of injuries in this area.

Antibiotic stewardship in orthopaedic surgery: principles and practice.

A thorough knowledge of the principles of antibiotic stewardship is a crucial part of high-quality orthopaedic surgical care. These principles include (1) determining appropriate indications for antibiotic administration, (2) choosing the correct antibiotic based on known or expected pathogens, (3) determining the correct dosage, and (4) determining the appropriate duration of treatment. Antibiotic stewardship programs have a multidisciplinary staff that can help guide antibiotic selection and dosage. These programs also perform active surveillance of antimicrobial use and may reduce Clostridium difficile and other drug-resistant bacterial infections by providing expert guidance on judicious antibiotic usage. The emergence of antibiotic-resistant pathogens, the geographical diversity of these infecting pathogens, and the changing patient population require customization of prophylactic regimens to reduce infectious complications. A multidisciplinary approach to antibiotic stewardship can lead to improved patient outcomes and cost-effective medical care.

Annexin A6 Interacts With p65 and Stimulates NF‐κB Activity and Catabolic Events in Articular Chondrocytes

OBJECTIVE ANXA6, the gene for annexin A6, is highly expressed in osteoarthritic (OA) articular chondrocytes but not in healthy articular chondrocytes. This study was undertaken to determine whether annexin A6 affects catabolic events in these cells. METHODS Articular chondrocytes were isolated from Anxa6-knockout mice, wild-type (WT) mice, and human articular cartilage in which ANXA6 was overexpressed. Cells were treated with interleukin-1β (IL-1β) or tumor necrosis factor α (TNFα), and expression of catabolic genes and activation of NF-κB were determined by real-time polymerase chain reaction and luciferase reporter assay. Anxa6(-/-) and WT mouse knee joints were injected with IL-1β or the medial collateral ligament was transected and partial resection of the medial meniscus was performed to determine the role of Anxa6 in IL-1β-mediated cartilage destruction and OA progression. The mechanism by which Anxa6 stimulates NF-κB activity was determined by coimmunoprecipitation and immunoblot analysis of nuclear and cytoplasmic fractions of IL-1β-treated Anxa6(-/-) and WT mouse chondrocytes for p65 and Anxa6. RESULTS Loss of Anxa6 resulted in decreased NF-κB activation and catabolic marker messenger RNA (mRNA) levels in IL-1β- or TNFα-treated articular chondrocytes, whereas overexpression of ANXA6 resulted in increased NF-κB activity and catabolic marker mRNA levels. Annexin A6 interacted with p65, and loss of Anxa6 caused decreased nuclear translocation and retention of the active p50/p65 NF-κB complex. Cartilage destruction in Anxa6(-/-) mouse knee joints after IL-1β injection or partial medial meniscectomy was reduced as compared to that in WT mouse joints. CONCLUSION Our data define a role of annexin A6 in the modulation of NF-κB activity and in the stimulation of catabolic events in articular chondrocytes.

The role of ANK interactions with MYBBP1a and SPHK1 in catabolic events of articular chondrocytes

OBJECTIVE To determine the role of progressive ankylosis protein (ANK)/Myb-binding protein 1a (MYBBP1a) and sphingosine kinase 1 (SPHK1) interactions in catabolic events of articular chondrocytes. METHOD ANK/MYBBP1a and SPHK1 interactions were identified using yeast two-hybrid screening and co-immunoprecipitation. To determine the role of these interactions in catabolic events of articular chondrocytes, ank/ank and wild type (WT) mouse chondrocytes transfected with full-length or mutant ank expression vectors (EVs) or femoral heads were treated with interleukin-1beta (IL-1β) in the absence or presence of SPHK inhibitor. Catabolic marker mRNA levels were analyzed by real time PCR; proteoglycan loss using safranin O staining and MMP-13 immunostaining were determined in femoral head explants; NF-κB activity was determined by transfecting chondrocytes with an NF-κB-specific luciferase reporter and analyzing nuclear translocation of p65 by immunoblotting; MYBBP1a nuclear or cytoplasmic amounts were determined by immunohistochemistry and immunoblotting. RESULTS The ANK N-terminal region interacted with SPHK1, whereas a cytoplasmic C-terminal loop interacted with MYBBP1a. Lack of ANK/MYBBP1a and SPHK1 interactions in ank/ank chondrocytes resulted in increased MYBBP1a nuclear amounts and decreased SPHK1 activity, and consequently decreased NF-κB activity, catabolic marker mRNA levels, proteoglycan loss, and MMP-13 immunostaining in IL-1β-treated articular chondrocytes or femoral heads. Transfection with full-length ank EV reduced nuclear MYBBP1a amounts and fully restored SPHK and NF-κB activities in IL-1β-treated ank/ank chondrocytes, whereas transfection with P5L or F376del mutant ank reduced nuclear MYBBP1a or increased SPHK activity, respectively, and consequently either transfection only partially restored NF-κB activity. CONCLUSION ANK/MYBBP1a and SPHK1 interactions stimulate catabolic events in IL-1β-mediated cartilage degradation.

Therapeutic approaches to skeletal muscle repair and healing.

Context: Skeletal muscle is comprised of a highly organized network of cells, neurovascular structures, and connective tissue. Muscle injury is typically followed by a well-orchestrated healing response that consists of the following phases: inflammation, regeneration, and fibrosis. This review presents the mechanisms of action and evidence supporting the effectiveness of various traditional and novel therapies at each phase of the skeletal muscle healing process. Evidence Acquisition: Relevant published articles were identified using MEDLINE (1978-2013). Study Design: Clinical review. Level of Evidence: Level 3. Results: To facilitate muscle healing, surgical techniques involving direct suture repair, as well as the implantation of innovative biologic scaffolds, have been developed. Nonsteroidal anti-inflammatory drugs may be potentially supplanted by nitric oxide and curcumin in modulating the inflammatory pathway. Studies in muscle regeneration have identified stem cells, myogenic factors, and β-agonists capable of enhancing the regenerative capabilities of injured tissue. Furthermore, transforming growth factor-β1 (TGF-β1) and, more recently, myostatin and the rennin-angiotensin system have been implicated in fibrous tissue formation; several antifibrotic agents have demonstrated the ability to disrupt these systems. Conclusion: Effective repair of skeletal muscle after severe injury is unlikely to be achieved with a single intervention. For full functional recovery of muscle there is a need to control inflammation, stimulate regeneration, and limit fibrosis. Strength-of-Recommendation Taxonomy (SORT): B

Annexins: Novel Therapeutic Targets for the Treatment of Osteoarthritis?

Osteoarthritis (OA) is the most common form of arthritis, affecting an estimated 27 million Americans. 1 The lack of current treatments to slow OA progression is due to the lack of both early detection methods and therapeutic targets for OA. Thus, there is an urgent need for the discovery of potential new therapeutic targets for the treatment of OA. Annexins are cytoplasmic proteins that, in the presence of Ca 2+ , translocate and bind to membranes. The role of annexins in disease pathology is an emerging field of investigation, with many studies highlighting the role of annexins not only as prognostic and diagnostic markers but also as being actively involved in causing diseases such as Alzheimer’s disease, autoimmunity, cancer, diabetes, and cardiovascular diseases. Specifically, their modulatory action on major signaling pathways involved in disease pathologies has made the annexins novel and exciting therapeutic targets. 2

Preoperative Bariatric Surgery and the Risk of Readmission Following Total Joint Replacement

The purpose of this study was to compare nonelective and all-cause readmission rates and to identify risk factors for readmission of total joint arthroplasty (TJA) patients who had preoperative bariatric surgery (BS) compared with TJA patients without preoperative BS. The New York Statewide Planning and Research Cooperative System database was queried to identify 343,710 TJA patients between 2005 and 2014. Three patient groups were evaluated: group 1 (patients with preoperative BS within 2 years of TJA [N=1478]); group 2 (obese patients without preoperative BS [N=60,259]); and group 3 (nonobese patients without preoperative BS [N=281,973]). Nonelective and all-cause readmission rates (30 days, 90 days, and 1 year) were compared, and multivariate analyses of readmission risk factors were performed. Group 1 had no significant difference in nonelective readmission rates compared with groups 2 and 3. However, when elective TJA readmissions were included, group 1 had significantly higher all-cause readmission rates at 30 days, 90 days, and 1 year compared with groups 2 and 3. Bariatric surgery was not a risk factor for nonelective readmissions at any time point. When elective TJA admissions were included, BS was an independent risk factor for all-cause readmission at all time points. Patients who have BS prior to TJA do not have higher nonelective readmission rates than obese TJA patients without BS. Bariatric surgery is not a risk factor for nonelective readmissions. However, BS is a significant predictor of elective TJA admissions up to 1 year following the index TJA. [Orthopedics. 2018; 41(2):107-114.].

Posterior Cruciate Ligament Avulsion Fractures

Purpose of ReviewThe purposes of this review are to (1) discuss the epidemiology and workup of the rare posterior cruciate ligament (PCL) avulsion fracture, (2) review the indications for nonoperative and operative management of patients with PCL avulsion fractures, (3) examine surgical outcomes in this patient population, and (4) discuss the authors’ preferred management algorithm and surgical approach.Recent FindingsIn accordance with the rarity of these injuries, the literature is sparse regarding surgical outcomes. Many of these injuries are in the setting of a multi-ligamentous injury. Most authors suggest that displaced PCL avulsion fractures should undergo operative fixation and current data suggests excellent outcomes when treating these patients with either open or arthroscopic fixation, with a low complication rate.SummaryPCL avulsion fractures, although rare, should undergo fixation when displacement is present. Current studies report successful outcomes and a low complication rate.

Clinical Utility of Continuous Radial MRI Acquisition at 3T in Patellofemoral Kinematic Assessment

Objectives: Continuous gradient-echo (GRE) acquisition or “dynamic magnetic resonance imaging”, allows for high-speed examination of pathologies based on joint motion. We sought to assess the efficacy of a radial GRE sequence with in the characterization of patellofemoral maltracking. Methods: Patients with suspected patellofemoral maltracking and asymptomatic volunteers were scanned using GRE (Siemens LiveView WIP; Malvern, PA, USA) at 3T in the axial plane at the patella level through a range of flexion-extension (0-30°). The mean time to perform the dynamic component ranged from 3-7 mins. Lateral maltracking (amount patella moved laterally through knee ranging) was measured. Patella lateralization was categorized as normal (≤ 2mm), mild (2-5mm), moderate (5-10mm), or severe (>10mm). Tibial tuberosity:trochlear groove (TT:TG) distance, trochlea depth, Insall-Salvati ratio, and patellofemoral cartilage quality (according to the modified Outerbridge grading system) were also assessed. Results: Eighteen symptomatic (6 men; 12 women, age range 14-51 years) and 10 asymptomatic subjects (6 men; 4 women, age range 25-68 years) were included. Two symptomatic patients underwent bilateral examinations. Lateralization in the symptomatic group was normal (n=10), mild (n=2), moderate (n=5) and severe (n=3). There was no abnormal maltracking in the volunteer group. Lateral tracking significantly correlated with TT:TG distance (F=38.0; p<.0001), trochlea depth (F=5.8; p=.023), Insall-Salvati ratio (F=4.642; p=.04) and Outerbridge Patella score (F=6.6; p=.016). Lateral tracking did not correlate with Outerbridge Trochlear score. Conclusion: Lateral tracking measured on GRE was found to significantly correlate with current measures of patellar instability including, TT:TG, trochlea depth, and the Insall-Salvati ratio. GRE is a rapid and easily performed addition to the standard protocol for kinematic patellofemoral motion and can add dynamic information on patellofemoral tracking. This may be help determine if an isolated MPFL or an MPFL reconstruction and tibial tubercle osteotomy is needed to treat patella instability.

Meniscal Allograft Transplantation Made Simple: Bridge and Slot Technique

Over recent years, appreciation for the critical role of the meniscus in joint biomechanics has led to an emphasis on meniscal preservation. Meniscal allograft transplant (MAT) is a promising biological solution for the symptomatic young patient with a meniscus-deficient knee that has not developed advanced osteoarthritis. As surgical techniques are refined and outcomes continue to improve, it is vital to consider the utility of such procedures and offer a straightforward approach to MAT. This article and accompanying video provide a step-by-step tutorial on how to perform a MAT using the bridge and slot technique, its key pearls and pitfalls as well as the relevant advantages and disadvantages of MAT.