Robert Molloy

Failed treatment of peroneal tendon injuries

As with most musculoskeletal disorders, understanding the anatomy and function of the peroneus longus and brevis tendons is paramount to the appropriate diagnosis and treatment of their pathologic conditions. This article helps the reader prevent treatment failures by reviewing the anatomy, function, and common treatment options for various disorders of the peroneal tendons. Finally, a discussion of common treatment failures will highlight pitfalls to be avoided.

A computer model of the position of the combined component in the prevention of impingement in total hip replacement

Dislocation remains a major concern after total hip replacement, and is often attributed to malposition of the components. The optimum position for placement of the components remains uncertain. We have attempted to identify a relatively safe zone in which movement of the hip will occur without impingement, even if one component is positioned incorrectly. A three-dimensional computer model was designed to simulate impingement and used to examine 125 combinations of positioning of the components in order to allow maximum movement without impingement. Increase in acetabular and/or femoral anteversion allowed greater internal rotation before impingement occurred, but decreases the amount of external rotation. A decrease in abduction of the acetabular components increased internal rotation while decreasing external rotation. Although some correction for malposition was allowable on the opposite side of the joint, extreme degrees could not be corrected because of bony impingement. We introduce the concept of combined component position, in which anteversion and abduction of the acetabular component, along with femoral anteversion, are all defined as critical elements for stability.

Rivaroxaban Use for Thrombosis Prophylaxis Is Associated With Early Periprosthetic Joint Infection

BACKGROUND Periprosthetic joint infection is a disastrous complication after total hip arthroplasty (THA) and total knee arthroplasty (TKA). The use of certain agents to prevent deep vein thrombosis after arthroplasty has been linked to an increased risk of adverse effects including wound drainage and infection. Adverse effects of one alternative, rivaroxaban, was studied in a single community hospital. METHODS International Classification of Diseases, Clinical Modification 9 codes were used to identify primary THAs and TKAs in an administrative database at one large-volume community hospital performed in 2012. Patients were divided into 2 groups: the study group received rivaroxaban, whereas the control group received another form of chemical thromboprophylaxis for at least 2 weeks postoperative. Demographics, risk factors, and illness severity scores were collected for each group. The primary measured outcome was the incidence of deep surgical site infection (SSI) within 30 days postoperative. RESULTS A total of 639 TKA or THA patients were included, with 159 patients who received rivaroxaban and 480 who received another form of chemical thromboprophylaxis. There were no significant differences between groups regarding demographics, risk factors, or illness severity scores. Incidence of early deep SSI in the rivaroxaban group was higher than in the control group (2.5% vs 0.2%; P < .015). CONCLUSION The use of rivaroxaban for thromboprophylaxis led to a significantly increased incidence of deep SSI in a continuous series of patients undergoing primary THA and TKA in a single institution.

Comparison of Acetabular Shell Position Using Patient Specific Instruments vs. Standard Surgical Instruments: A Randomized Clinical Trial

Total hip arthroplasty (THA) survivorship relies largely upon appropriate acetabular cup placement. The purpose of this prospective randomized controlled trial was to determine whether the use of a preoperative 3D planning software in combination with patient specific instrumentation (PSI) results in improved cup placement compared with traditional techniques. Thirty-six THA patients were randomized into standard (STD) or PSI technique. Standard approach was completed using traditional techniques, while PSI cases were planned and customized surgical instruments were manufactured. Postoperative CT scans were used to compare planned to actual results. Differences found between planned and actual anteversion were -0.2° ± 6.9° (PSI) and -6.9°±8.9° (STD) (P = 0.018). Use of 3D preoperative planning along with PSIs resulted in significantly greater anteversion accuracy than traditional planning and instrumentation.

Prospective Randomized Evaluation of a Collagen/Thrombin and Autologous Platelet Hemostatic Agent During Total Knee Arthroplasty

The purpose of this study was to evaluate the effectiveness of a collagen/thrombin and autologous platelet hemostatic agent in preventing blood loss during primary total knee arthroplasty. This prospective, double-blinded, randomized study was designed to enroll a total of 100 patients. Patients were randomized 1:1 to either the treatment arm (standard hemostasis plus study product) or the control arm (standard hemostasis alone). Transfusion requirements, as determined by a blinded investigator using standardized criteria, were significantly lower in the treatment group (no blood transfusions) compared with the control group (5 transfusions; P = .007). These data support the addition of the study product to prevent blood transfusions after primary total knee arthroplasty.

Classification systems of hip osteonecrosis: an updated review

PurposeOsteonecrosis of the femoral head (ONFH) typically impacts middle-aged patients who are typically more active and in whom many surgeons would try to delay performing a total hip arthroplasty (THA). This poses a clinical decision-making challenge. Therefore, several options for joint preservation have been advocated, but varying indications and success rates have led to debate on when to use the various procedures. This is due in part to the lack of a generalized system for assessing ONFH, as well as the absence of a standardized method of data collection for patient stratification. Due to the paucity of studies, in this review, we aimed to provide an up-to-date review of the most widely utilized classification systems and discuss the characteristics of each system.MethodsA comprehensive literature review was conducted. Studies published between January 1st, 1975 and March 1st, 2018 were reviewed. The following key words were used in combination with Boolean operators AND or OR for the literature search: “osteonecrosis,” “avascular necrosis,” “hip,” “femoral head,” “classification,” “reliability,” and “validity.” We defined the inclusion criteria for qualifying studies for this review as follows: (1) studies that reported on the classification systems for hip osteonecrosis, (2) studies that reported on the inter-observer reliability of the classification systems, and (3) studies that reported on the intra-observer reliability of any ONFH classification systems. In addition, we employed the following exclusion criteria: (1) studies that assessed classification systems for traumatic osteonecrosis, (2) Legg-Calvé-Perthes disease, or (3) Developmental Dysplasia of the Hip. Additionally, we excluded case reports and duplicate studies among searched databases.ResultsThe following classification systems were the most commonly utilized: The Ficat and Arlet, Steinberg, the Association Research Circulation Osseous (ARCO), and the Japanese Investigation Committee (JIC) classification systems. The details of each system have been discussed and their inter- and intra-observer reliability has been compared.ConclusionTo this date, there is a lack of consensus on a universal and comprehensive system, and the use of any of the previous classification systems is a matter of dealer’s choice. The Ficat and Arlet system was the earliest yet remains the most widely utilized system. Newer classification systems have been developed and some such as the JIC shows promising prognostic value while maintaining simplicity. However, larger validating studies are needed. While all of these systems have their strengths, the lack of a unified classification and staging system is still a problem in the diagnosis and prognosis ONFH. Further multi-center collaborative efforts among osteonecrosis experts are needed to adopt a universal classification system that may positively reflect on patient’s outcomes.

Treatment Challenges of Prosthetic Hip Infection with Associated Iliacus Muscle Abscess: Report of 5 Cases and Literature Review

Prosthetic joint infection is an unfortunate though well-recognized complication of total joint arthroplasty. An iliacus and/or iliopsoas muscle abscess is a rarely documented presentation of hip prosthetic joint infection. It is thought an unrecognized retroperitoneal nidus of infection can be a source of continual seeding of the prosthetic hip joint, prolonging attempts to eradicate infection despite aggressive debridement and explant attempts. The current study presents five cases demonstrating this clinical scenario, and discusses various treatment challenges. In each case we report the patients clinical history, pertinent imaging, management and outcome. Diagnosis of the iliacus muscle abscess was made using computed tomography imaging. In brief, the mean number of total drainage procedures (open and percutaneous) per patient was 4.2, and outcomes consisted of one patient with a hip girdlestone, two patients with delayed revisions, and two patients with retained prosthesis. All patients ended with functional pain and on oral antibiotic suppression with an average follow up of 18 months. This article highlights an iliacus muscle abscess as an unrecognized source of infection to a prosthetic hip. It demonstrates resilience to standard treatment protocols for prosthetic hip infection, and is associated with poor patient outcomes. Aggressive surgical debridement appears to remain critical to treatment success, and early retroperitoneal debridement of the abscess should be considered.

Prospective randomised evaluation of a collagen/thrombin and autologous platelet haemostatic agent during cementless total hip arthroplasty

BACKGROUND Total hip arthroplasty (THA) can be associated with substantial peri-operative blood loss which can negatively influence a patients clinical outcome. Few haemostatic agents have been tested in THA. The aim of this study was to determine whether the use of a collagen/thrombin/ autologous platelet haemostatic agent would result in a significant decrease of blood transfusions for patients undergoing primary THA. MATERIALS AND METHODS THA patients meeting inclusion/exclusion criteria (n=109) were enrolled in this prospective, double-blind trial and randomised to a treatment arm (standard haemostatic methods plus haemostatic agent) or control arm (standard haemostatic methods only). The primary outcome was transfusion. Secondary outcome measures included peri-operative narcotic usage and post-operative haemoglobin levels, pain scores, function, and general health quality of life. RESULTS Transfusions were required by 5/60 (8.3%) patients in the treatment group and 7/49 (14.3%) in the control group (p=0.33). The mean number of units transfused was not significantly different between the treatment group (2.2±1.3) and the control group (1.6±0.5) (p=0.36). Haemoglobin values on post-operative days 1, 2, and 3 were significantly higher in the treatment group (p=0.002, 0.04, and 0.02, respectively). Hip Disability and Osteoarthritis Outcome Score and Short Form-12 scores were not different between the two groups. DISCUSSION In relatively healthy patients undergoing primary cementless THA there was no significant difference in number of transfusions or number of units transfused. It is unlikely that we will routinely use the investigated haemostatic agent to reduce blood loss in a healthy patient undergoing THA. The product may have some benefit in patients who refuse blood transfusions, have minimal ability to increase blood volume, are undergoing total joint revision, or have markedly low pre-operative haemoglobin levels, but this needs to be demonstrated.

Cementless Total Knee Arthroplasty: A Comprehensive Review of the Literature

This review evaluated (1) original and newer cementless implants; (2) outcomes of newer designs; (3) risks and benefits; and (4) newer cementless vs cemented total knee arthroplasties. A search for all reports on cementless total knee arthroplasties published from January 2010 to April 2017 was performed, and 31 studies were included for final analysis. Newer cementless total knee arthroplasty designs have shown excellent survivorship, functional outcomes, and satisfaction rates in both young and elderly populations. Compared with cement fixation, there may be potential benefits with the newer cementless implants. However, these findings need to be further substantiated with additional studies reporting longer-term results. [Orthopedics. 2018; 41(5):263-273.].

Evidence-Based Management of Trunnionosis in Metal-on-Polyethylene Total Hip Arthroplasty: A Systematic Review

Multiple recent reports have indicated a rising awareness of trunnionosis-related implant failures, accounting for up to 3% of all total hip arthroplasty revisions. Moreover, aseptic loosening and osteolysis from local release of metal debris can be the presenting manifestations, and thus the true incidence of trunnionosis is thought to be underreported. Furthermore, the relatively unclear and multifactorial pathogenesis and the widely variable clinical presentations pose a diagnostic challenge. A consensus regarding the ideal intervention and its timing is also lacking. Because of the relative paucity of reports regarding the diagnosis and management of trunnionosis, we conducted this evidence-based review to evaluate the (1) incidence, (2) pathogenesis, (3) diagnosis, and (4) treatment of trunnionosis in metal-on-polyethylene total hip arthroplasty. We then propose an algorithm for the diagnostic work-up and management of this condition.