Norman A. Johanson

Prevention of VTE in Nonsurgical Patients: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines

BACKGROUND VTE is a serious, but decreasing complication following major orthopedic surgery. This guideline focuses on optimal prophylaxis to reduce postoperative pulmonary embolism and DVT. METHODS The methods of this guideline follow those described in Methodology for the Development of Antithrombotic Therapy and Prevention of Thrombosis Guidelines: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines in this supplement. RESULTS In patients undergoing major orthopedic surgery, we recommend the use of one of the following rather than no antithrombotic prophylaxis: low-molecular-weight heparin; fondaparinux; dabigatran, apixaban, rivaroxaban (total hip arthroplasty or total knee arthroplasty but not hip fracture surgery); low-dose unfractionated heparin; adjusted-dose vitamin K antagonist; aspirin (all Grade 1B); or an intermittent pneumatic compression device (IPCD) (Grade 1C) for a minimum of 10 to 14 days. We suggest the use of low-molecular-weight heparin in preference to the other agents we have recommended as alternatives (Grade 2C/2B), and in patients receiving pharmacologic prophylaxis, we suggest adding an IPCD during the hospital stay (Grade 2C). We suggest extending thromboprophylaxis for up to 35 days (Grade 2B). In patients at increased bleeding risk, we suggest an IPCD or no prophylaxis (Grade 2C). In patients who decline injections, we recommend using apixaban or dabigatran (all Grade 1B). We suggest against using inferior vena cava filter placement for primary prevention in patients with contraindications to both pharmacologic and mechanical thromboprophylaxis (Grade 2C). We recommend against Doppler (or duplex) ultrasonography screening before hospital discharge (Grade 1B). For patients with isolated lower-extremity injuries requiring leg immobilization, we suggest no thromboprophylaxis (Grade 2B). For patients undergoing knee arthroscopy without a history of VTE, we suggest no thromboprophylaxis (Grade 2B). CONCLUSIONS Optimal strategies for thromboprophylaxis after major orthopedic surgery include pharmacologic and mechanical approaches.

American Academy of Orthopaedic Surgeons Lower Limb Outcomes Assessment Instruments: Reliability, Validity, and Sensitivity to Change

BACKGROUND The American Academy of Orthopaedic Surgeons (AAOS) has developed an array of outcomes assessment instruments designed for the efficient collection of outcomes data from patients of all ages with musculoskeletal conditions in all body regions. The Lower Limb Instruments were developed through a process of literature review, consensus-building, and field-testing. METHODS The instruments were distributed to a total of 290 subjects in twenty orthopaedic practices throughout the United States and Canada. Of the 290 patients, seventy each had a diagnosis in the categories of foot and ankle, sports/knee, and hip and knee and forty each had a diagnosis in the categories of trauma and rehabilitation. Retests to be taken twenty-four hours after the first test were distributed to subsamples of patients for each instrument. Seventy-one one-year follow-up questionnaires (twenty-five Sports/Knee, twenty-five Foot and Ankle, sixteen Hip and Knee, and five Lower Limb Core instruments) were returned. RESULTS The Lower Limb Core Scale and the Hip and Knee Core Scale, each consisting of seven items addressing pain, stiffness and swelling, and function, performed at an acceptable level. Additional Sports/Knee and Foot and Ankle Modules proved to have internal and retest reliability of 0.80 or better, comparable with the values for well-established measures such as the Short Form-36 (SF-36). All of the new scales were moderately to strongly correlated with other measures of pain and function, such as physician ratings, the SF-36, and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Seventy-one patients provided follow-up information for the analysis of sensitivity to change. The Lower Limb Core was found to contribute independently to the prediction of the transition score based on the patient and physician assessments of change. CONCLUSIONS The AAOS Lower Limb Instruments for outcomes assessment are highly reliable and are correlated with other measures for similar constructs. They are also sensitive to change in patient status. The Lower Limb Core Scale may be used with attribution of pain either to the lower limb or to a specific joint or side without sacrificing reliability. Combined with the SF-36, the AAOS outcomes assessment instruments comprehensively and efficiently measure outcomes in orthopaedic patients with lower-limb conditions.

Indications for total hip and total knee arthroplasties. Results of orthopaedic surveys.

A lack of consensus regarding the indications for total hip arthroplasty (THA) and total knee arthroplasty (TKA) has been cited as one reason for the variations in the rates of THA and TKA across the United States. The purposes of this study were to survey orthopaedists in a specific geographic area (New York City) regarding the candidacy of patients with osteoarthritis for THA or TKA and to compare indications for THA between orthopaedists at two academic medical centers, The Hospital for Special Surgery in the United States and McGill University in Canada. Orthopaedists were sent mail surveys asking about indications, factors affecting outcomes, and factors that might modify decisions for surgery. Approximately 45% of orthopaedists who performed THA and TKA in New York City in 1992 completed the surveys. Although there were wide variations among surgeons, most surgeons required at least severe pain daily, rest pain several days per week, transfer pain either several days per week (THA) or daily (TKA), and destruction of most of the joint space on radiograph. Younger age, comorbidity, technical difficulties, and lack of motivation modified the decision against surgery, whereas the desire to be independent and return to work swayed the decision for surgery. Most surgeons rated that patients with severe pain, osteoarthritis, or rheumatoid arthritis would have a high likelihood of an excellent outcome, whereas those with comorbidity and certain technical factors would have only a moderate likelihood of an excellent outcome. In the U.S.-Canadian survey of THA, in which more than 90% of surgeons responded, Canadian surgeons tended to require more frequent pain and use of assistive devices for walking. Although there was a majority of opinion for several indications, there was no clear consensus among surgeons regarding the indications for THA and TKA. Possible explanations for this are that isolated indications are not as important as integrating and weighing several indications and that the patients desire to proceed with THA or TKA is an important driving force in the decision to operate.

Instructional Course Lectures, The American Academy of Orthopaedic Surgeons - Common Complications of Total Knee Arthroplasty*†

The success of a total joint arthroplasty is contingent on a clear understanding of the potential complications of the procedure. This Instructional Course Lecture presents a review of specific problems related to wound-healing, neurovascular injuries, infections, thromboembolic disease, the extensor mechanism, stiffness, and periprosthetic fractures to provide the reader with a clear understanding of ways to avoid and treat these common complications. Primary wound-healing is critical for the success of any total knee arthroplasty. Any delay in wound-healing increases the risk of infection and failure of the arthroplasty214,216. The prevention of soft-tissue problems through the selection of the proper skin incision, an understanding of the vascular anatomy and patient-related risk factors, and prompt treatment of wound problems (should they arise) are imperative if a good result is to be achieved. ### Vascular Anatomy The blood supply to the soft tissues of the anterior aspect of the knee is completely random, with contributions from multiple vessels2,23,43,161,203,258,295. This blood supply arises predominantly from the terminal branches of the peripatellar anastomotic arterial ring, which has numerous contributing arterial branches, including the medial and lateral superior genicular arteries, the medial and lateral inferior genicular arteries, the supreme genicular artery, the anterior tibial recurrent artery, and a branch of the profunda femoris artery. In contrast to the skin circulation of the thigh proximal to the knee, there is no underlying muscle or intermuscular septum directly anterior to the knee to provide a direct pathway for arterial perforators43,161. Skin circulation in this area is dependent on the dermal plexus, which originates directly from arterioles traveling within the subcutaneous fascia. Any operative dissection performed superficial to this subcutaneous fascia disrupts the arterial supply to the skin and increases …

Nerve Injury in Total Hip Arthroplasty

The causative factors and the clinical course of symptoms related to nerve injury in total hip arthroplasty were evaluated in 34 patients who underwent surgery during the period from 1969 to 1981. The overall incidence of this complication was 0.6%, with an incidence of 1.0% during the first seven years and of 0.3% during the following six years of the study. Female patients, particularly those with congenital hip dislocation, appeared to be at higher risk of sustaining nerve injury. Pathogenetic mechanisms of nerve injury identified in 47% of the patients included lengthening and/or lateral displacement of the proximal femur, subfascial hematoma formation, prosthetic dislocation, and partial nerve transection. Greater blood loss and longer surgical times were distinguishing features of the nerve injury group as compared with large series of total hip arthroplasties performed during similar periods by the same surgical approaches. Causalgic pain was a significant sequela of nerve injury, and its strong association with bleeding problems was observed. With the exception of causalgic pain, persistent neurologic dysfunction in 79% of these patients at an average of 3.7 years after operation did not cause significant disability.

Prevention of Deep-Vein Thrombosis after Total Hip Arthroplasty. Comparison of Warfarin and Dalteparin*

The effectiveness and safety of warfarin were compared with those of a low-molecular-weight heparin (dalteparin) for the prevention of deep-vein thrombosis after total hip arthroplasty in a prospective, randomized, multi-institutional trial. Patients who were older than eighteen years of age and were scheduled to have an elective primary or revision total hip arthroplasty were eligible; 580 patients were randomized, 550 had the operation and received prophylaxis, and 382 had evaluable venograms. Prophylaxis was provided either with warfarin beginning the night before the operation or with dalteparin beginning two hours before the operation and was continued until venography was performed. Bleeding was assessed on the basis of intraoperative blood loss, transfusion requirements, a decrease in hematocrit, and clinically identified bleeding complications. The prevalence of deep-vein thrombosis was found to be significantly lower in the patients who had received dalteparin than in those who had received warfarin (twenty-eight [15 per cent] of 192 patients compared with forty-nine [26 per cent] of 190 patients; p = 0.006). Deep-vein thrombosis occurred in the calf veins of twenty-one patients (11 per cent) who had received dalteparin and of forty-three patients (23 per cent) who had received warfarin; this difference was significant (p = 0.003). Proximal deep-vein thrombosis occurred in ten patients (5 per cent) who had received dalteparin and in sixteen patients (8 per cent) who had received warfarin; however, with the numbers available, no significant difference could be detected (p = 0.185). We also could not detect a significant difference with regard to the intraoperative and postoperative blood loss, the decrease in hematocrit, and the prevalence of major bleeding complications between the two groups; however, the patients who had received dalteparin had a significantly higher prevalence of bleeding complications involving the operative site (p = 0.03), and a significantly greater percentage required postoperative transfusions (p = 0.001). We concluded that preoperative prophylaxis with dalteparin is significantly more effective than that with warfarin in preventing deep-vein thrombosis after total hip arthroplasty. The greater effectiveness of dalteparin must be considered, however, in light of an increased need for postoperative transfusions and an increase in the prevalence of wound-related bleeding complications.

Prevention of Symptomatic Pulmonary Embolism in Patients Undergoing Total Hip or Knee Arthroplasty

This clinical practice guideline is based on a systematic review of published studies on the management of adult patients undergoing total hip replacement (THR) or total knee replacement (TKR) aimed specifically at preventing symptomatic pulmonary embolism (PE). The guideline emphasizes the need to assess the patients risk for both PE and postoperative bleeding. Mechanical prophylaxis and early mobilization are recommended for all patients. Chemoprophylactic agents were evaluated using a systematic literature review. Forty-two studies met eligibility criteria, of which 23 included patients who had TKR and 25 included patients who had THR. The following statements summarize the recommendations for chemoprophylaxis: Patients at standard risk of both PE and major bleeding should be considered for aspirin, low-molecular-weight heparin (LMWH), synthetic pentasaccharides, or warfarin with an international normalized ratio (INR) goal of < or =2.0. Patients at elevated (above standard) risk of PE and at standard risk of major bleeding should be considered for LMWH, synthetic pentasaccharides, or warfarin with an INR goal of < or =2.0. Patients at standard risk of PE and at elevated (above standard) risk of major bleeding should be considered for aspirin, warfarin with an INR goal of < or =2.0, or none. Patients at elevated (above standard) risk of both PE and major bleeding should be considered for aspirin, warfarin with an INR goal of < or =2.0, or none.

Medical Errors in Orthopaedics. Results of an AAOS Member Survey

BACKGROUND There has been widespread interest in medical errors since the publication of To Err Is Human: Building a Safer Health System by the Institute of Medicine in 2000. The Patient Safety Committee of the American Academy of Orthopaedic Surgeons has compiled the results of a member survey to identify trends in orthopaedic errors that would help to direct quality assurance efforts. METHODS Surveys were sent to 5540 Academy fellows, and 917 were returned (a response rate of 16.6%), with 53% (483) reporting an observed medical error in the previous six months. RESULTS A general classification of errors showed equipment (29%) and communication (24.7%) errors with the highest frequency. Medication errors (9.7%) and wrong-site surgery (5.6%) represented serious potential patient harm. Two deaths were reported, and both involved narcotic administration errors. By location, 78% of errors occurred in the hospital (54% in the surgery suite and 10% in the patient room or floor). The reporting orthopaedic surgeon was involved in 60% of the errors; a nurse, in 37%; another orthopaedic surgeon, in 19%; other physicians, in 16%; and house staff, in 13%. Wrong-site surgeries involved the wrong side (59%); another wrong site, e.g., the wrong digit on the correct side (23%); the wrong procedure (14%); or the wrong patient (5% of the time). The most frequent anatomic locations were the knee and the fingers and/or hand (35% for each), the foot and/or ankle (15%), followed by the distal end of the femur (10%) and the spine (5%). CONCLUSIONS Medical errors continue to occur and therefore represent a threat to patient safety. Quality assurance efforts and more refined research can be addressed toward areas with higher error occurrence (equipment and communication) and high risk (medication and wrong-site surgery).

Challenges with health-related quality of life assessment in arthroplasty patients: problems and solutions.

Assessment of health‐related quality of life (HRQOL) using patient‐reported outcomes in arthroplasty has become popular because it provides a unique perspective on successful elective procedures. However, challenges exist in the assessment of HRQOL in clinical practice and in clinical research. Patient compliance with multiple and sometimes lengthy HRQOL assessments administered at multiple follow‐up visits is problematic. Many well‐validated HRQOL instruments are available, and progress has been made in defining the minimal clinically important difference in hip and knee arthroplasty that denotes the minimal change perceived to be important by patients. Challenges in understanding the literature are attributable to the use of various HRQOL scales, with different scoring ranges and scoring algorithms, different interpretations of highest score, and differences in the presentation of raw versus transformed scores.

The microscopic anatomy of the bone-cement interface in failed total hip arthroplasties.

Thirty specimens were removed from the bone-cement interface in 25 hips revised for aseptic loosening of total hip arthroplasty. Histologic examination of the membranous tissues revealed that histiocytosis, fibrosis, and necrosis were present in every specimen. Other prominent features included particles of acrylic cement, polyethylene debris, and fragments of necrotic bone. Mechanical failure was characterized by cement fractures, and microfracture of bone. The presence of cement debris and bone detritus in the membranes, and smooth appearance of the removed cement mantles substantiated the presence of mechanical failure. The process of loosening was characterized by the recruitment of histiocytes into the interface and the subsequent resorption of bone around the prosthesis. This may be a manifestation of the rate of cement wear and tear, particle size, and the immunologic predispositions of the host. These observations on interfaces of loosened prostheses are reexamined and reinterpreted in the light of radiologic observations on interface radiolucent zones and well-functioning prostheses.