WHAT’S NEW: Bearing use in the United States has evolved where the majority of liners used in the socket portion of a hip replacement are cross-link polyethylene. The head material is evenly split between ceramic and metal with similar results at 10+ years followup. Head sizes larger than 36 mm are discouraged.
MODULARITY: Use of modular implants that have separate stem and neck segments have decreased dramatically due to wear between the modular metal stem and metal neck. Modularity between the stem and ball portion remains the standard of implant design.
COMPLICATIONS FOLLOWING HIP REPLACEMENT: Complications have remained similar, with infection and dislocation being the 2 primary causes of revision in hip replacement. Prevention of infection has become more of a dominant issue, with most centers using some form of preoperative wash to decrease the number of bacteria on the skin and either treating patients with nasal antibiotics or an iodine type solution to minimize staph bacteria in the patient’s nose prior to surgery. Prevention of deep vein thrombosis has evolved over the last several years, with the most common prophylaxis being either low-dose or regular-dose aspirin. There has been an association between formal anticoagulation using either warfarin or some form of oral agent and increased risk of infection due to hematoma formation around the hip.
SURGICAL VOLUME AND COMPLICATIONS: There have been several studies looking at the difference between high-volume and low-volume hospitals, as well as high-volume and low-volume surgeons. They found that there are lower rates of complications in high-volume centers and with high-volume surgeons. They also found that elective joint replacement patients going to rehab centers or skilled nursing facilities are at increased risk of post-discharge adverse events compared to those patients who go directly home after surgery.
OPTIMIZATION OF PATIENTS: There has been increasing emphasis on optimizing patients’ medical comorbidities prior to surgery. These include addressing obesity, medical problems, smoking cessation, and management of diabetes. All of these factors need to be addressed prior to elective hip or knee replacement surgery.
PATIENT-RELATED FACTORS AFFECTING OUTCOMES IN TOTAL HIPS: There been several studies over the last several years looking at the association of prior lumbar spine surgery, specifically fusion, and increased rate of dislocation following hip replacement. It was noted that patients have as high as a 10-fold increase in the risk of dislocation if they have had prior lumbosacral fusions or have a fusion after their hip replacement.
CHRONIC OPIATE USE: Several studies have shown that patients that are using chronic pain medication have a lower success rate following hip replacement.
CURRENT CONTROVERSIES IN HIP REPLACEMENT: The majority of hip replacements done in the United States use cementless implants, and that appears to be the standard of care. Bearing surfaces, as previously mentioned, are either a metal or ceramic ball on cross-link polyethylene. There are several approaches to get into the hip, the most common being a posterolateral approach, but there has been increased enthusiasm for a direct anterior approach and, currently, approximately one-third of hip replacements done in the United States utilize a direct anterior approach. There are several potential advantages, including less postoperative pain, lower dislocation rate, and more accurate placement of the implants. At 1-year follow-up, there is no difference between an anterior or posterolateral approach to the hip.
RETURNING TO DRIVING AFTER JOINT REPLACEMENT: There have been multiple studies reviewing this subject. It is generally recommended that patients wait a minimum of 2 weeks following a right-sided hip replacement and 4 weeks following a right-sided knee replacement before returning to driving. This can vary based on the patient’s preoperative function and physical condition.
READMISSION RATE AFTER ELECTIVE TOTAL HIP REPLACEMENT: Several studies have evaluated this and found that, on average, 5% of patients are readmitted to the hospital within 30 days and 6% were readmitted within 90 days after hip replacement. The reason for readmission varies depending on multiple factors. Multiple authors have evaluated this and found that the actual rate of readmission will never be 0% as the majority of readmissions are not preventable.
Dr. Barrett is an orthopedic surgeon who performs over 500 joint replacement surgeries annually. For more information about total hip and knee replacements, contact Proliance Orthopedic Associates at 425.656.5060.