Fourteen Year Follow-Up of Randomized Clinical Trials of Active Robotic-Assisted Total Hip Arthroplasty.

Background: Active robotic total hip arthroplasty (THA) has been used clinically for over 20 years, but long-term results have never been studied. The aims of this study are to determine whether active robotic THA improves clinical outcomes and results in fewer revisions over a long-term follow-up.

Methods: Patients from 2 US Food and Drug Administration clinical trials (1994-1998 and 2001-2006) who had undergone THA using either an active robotic system or a traditional manual technique were examined to determine if any differences existed in radiographic analysis and patient pain and function using the University of California, Los Angeles; visual analog scale; Health Status Questionnaire (HSQ) pain; HSQ role physical; HSQ physical functioning; Harris pain scores; and the total Western Ontario and McMaster Universities Osteoarthritis Index scores at a mean follow-up of 14 years.

A perspective on robotic assistance for knee arthroplasty.

Knee arthroplasty is used to treat patients with degenerative joint disease of the knee to reduce pain and restore the function of the joint. Although patient outcomes are generally quite good, there are still a number of patients that are dissatisfied with their procedures. Aside from implant design which has largely become standard, surgical technique is one of the main factors that determine clinical results.

Robotic-assisted TKA reduces postoperative alignment outliers and improves gap balance compared to conventional TKA.

Background: Several studies have shown mechanical alignment influences the outcome of TKA. Robotic systems have been developed to improve the precision and accuracy of achieving component position and mechanical alignment.

Questions/purposes: We determined whether robotic-assisted implantation for TKA (1) improved clinical outcome; (2) improved mechanical axis alignment and implant inclination in the coronal and sagittal planes; (3) improved the balance (flexion and extension gaps); and (4) reduced complications, postoperative drainage, and operative time when compared to conventionally implanted TKA over an intermediate-term (minimum 3-year) followup period.

Surgical technique: a cup-in-cup technique to restore offset in severe protrusio acetabular defects.

Background: Severe medial and/or superior defects encountered in revision THA are currently managed with jumbo (≥ 66 mm) acetabular components and modular augments, with reconstruction cages, or with the cup-cage technique. Preoperative planning can indicate when these techniques may not restore vertical and horizontal offset. Failure to restore offset can lead to impingement, leg length inequality, abductor weakness, and dislocation.

In vivo assessment of total hip femoral head separation from the acetabular cup during 4 common daily activities.

In vivo video fluoroscopies of well-functioning total hip arthroplasties (THA) have shown that femoral head separation from the medial articular bearing surface occurs during gait. Other activities may cause the same phenomenon. We examined this while patients performed the following 4 activities of daily living: pivoting to each side in stance, shoe tying, sitting down, and standing up.

A painful metal-on-metal total hip arthroplasty: a diagnostic dilemma.

Infection, loosening, osteolysis, or other causes can lead to the development of pain about a previously well-functioning total hip arthroplasty. An inflammatory reaction unique to metal on metal arthroplasty can lead to a painful total hip. A synovial biopsy is needed to make this specific diagnosis, and included in the differential diagnosis is infection.

Femoral anteversion in THA and its lack of correlation with native acetabular anteversion.

Several studies support the concept that, for optimum range of motion in THA, the combined femoral and acetabular anteversion should be some constant or fall within some "safe zone." When using a cementless femoral component, the surgeon has little control of the anteversion of the component since it is dictated by native femoral anteversion. Given this constraint, we asked whether the surgeon should use the native anteversion of the acetabulum as a target for implant position in THA.

Accuracy of computer navigation for acetabular component placement in THA.

The accuracy and precision of any computer-aided surgical device is critical to its utility. We asked the following question: how accurate and precise are the values measured by an imageless computer navigation system as compared with those measured using postoperative CT scans? Twenty-five patients (26 hips) underwent primary THA using an imageless computer navigation system for placement of the acetabular component. Inclination and anteversion were measured in the operative coordinate system as defined by Murray.

Robots in orthopaedic surgery: past, present, and future.

Robots are increasingly being developed for use in surgery to aid physicians in providing more precision, especially during procedures requiring fine movements that may be beyond the scope of the human hand. In addition, robots enable the surgeon to provide improved accuracy and reproducibility with the goal of better outcomes. To date, most robotic surgical systems are in the design and experimental stage.

Time to revision of primary THA is shorter for specialists than nonspecialists.

We asked if there was a shorter time to revision, and different indications for revision, for primary total hip arthroplasties performed in the community by general orthopaedic surgeons (nonspecialists) as compared with primary total hip arthroplasties performed by specialists. We retrospectively reviewed 560 revision total hip arthroplasties performed in 486 patients from 1998 to 2006 at our tertiary referral center. One hundred ninety revisions from the community (nonspecialists cohort) and 109 revisions for which the primary arthroplasty was performed by the specialists (specialist cohort) at our center met the criteria for inclusion.

Early aseptic loosening of a modern acetabular component secondary to a change in manufacturing.

Cementless acetabular reconstruction with a hemispheric acetabular shell in primary total hip arthroplasty has shown reproducible results. Ingrowth of bone into a porous coating of beads, a titanium fiber mesh, or a hydroxylapatite-containing bioactive coating has been histologically documented. Early failures of ingrowth of an acetabular component have been reported using a threaded acetabular design.

Prosthesis cost containment in total joint replacement: a physician-driven free-market approach.

As an alternative to a limited vendor/volume discount approach, our hospital employed a physician-driven free market strategy aimed at reducing joint implant costs. Surgeons were provided with vendor pricing and peer profile comparisons of implant cost data and asked to select implants providing the best value based on patient need. Vendors were challenged to reduce prices where appropriate.

Primary and revision total hip replacement using the Robodoc system.

The ROBODOC system was designed to address potential human errors in performing cementless total hip replacement. The system consists of a preoperative planning computer workstation (called ORTHODOC) and a five-axis robotic arm with a high speed milling device as an end effector. The combined experience of the United States Food and Drug Administration multicenter trial and the German postmarket use of the system are reported.

Incidence and time course of thromboembolic outcomes following total hip or knee arthroplasty.

Background: Little is known about the incidence and time course of clinical thromboembolic events after total hip or knee arthroplasty, particularly after hospital discharge.

Methods: We used a linked hospital discharge database provided by the State of California to identify cases diagnosed as having deep vein thrombosis or pulmonary embolism within 3 months of unilateral total hip or knee arthroplasty. Also, we surveyed orthopedic surgeons to estimate the frequency of postoperative thromboprophylaxis during July 1991 through June 1993.

Use of acetabular models in planning complex acetabular reconstructions.

The number of patients requiring revision total hip arthroplasty continues to increase each year. Accurate preoperative planning is a key factor in obtaining a good result. Radiographs provide little information concerning the actual extent of the acetabular defects.

Classification of femoral abnormalities in total hip arthroplasty.

Bony abnormalities of the femur can significantly complicate total hip arthroplasty both for the primary and revision operations. No standard nomenclature exists for the description of these femoral abnormalities. A classification system is presented to standardize nomenclature, assist in preoperative planning, and to assist in the reporting of these defects.

Robotic systems in surgery.

Computer-driven robots and medical imaging technology may soon enable surgeons to plan and execute intricate procedures with unprecedented precision. Our experience in introducing a robotic system for use in an active role in cementless total hip replacement surgery has convinced us that the marriage of these two technologies-robotics and medical imaging-is likely to change the way many types of surgical procedures are performed. The ability to link an image-based preoperative plan with its surgical execution by a robot may be the key to improved outcomes.