Metal-on-metal surface replacement: a triumph of hope over reason: affirms.

Metal-on-metal hip resurfacing offers some potential for total hip arthroplasty (THA) in the young patient. However, short- and intermediate-term results of the currently available implants have failed to demonstrate advantage over conventional THA. The risks of femoral neck fracture or avascular necrosis have been disappointing early limitations of the procedure.

Unexplained pain after THR: what should i do?

Early causes of hip pain within the first year of total hip replacement (THR) include failure of fixation, infection, instability, other sources of pain (eg, lumbar spine), and mechanical dysfunction such as psoas tendon impingement or other soft tissue irritation. Metal-on-metal THRs may present with pain due to hypersensitivity within the first 1 to 3 years after arthroplasty. Late causes of pain include loosening, wear reactions, or mechanical dysfunction such as subluxation associated with wear of the articular couple.

Surface Roughness of CoCr and ZrO(2) Femoral Heads with Metal Transfer: A Retrieval and Wear Simulator Study.

Metal transfer to femoral heads may result from impingement against the metallic acetabular shell following subluxation/dislocation, or when metallic debris enters the articulation zone. Such transfers roughen the head surface, increasing polyethylene wear in total hip replacements. Presently, we examined the surface roughness of retrieved femoral heads with metallic transfer.

Midflexion instability in revision total knee arthroplasty.

Midflexion instability is a new concept associated with revision total knee arthroplasty. It appears as rotational instability with combined external rotation and valgus stress in a knee flexed between 45 degrees and 90 degrees. Three main factors contribute to this instability: anterior medial collateral ligament attenuation, femoral-tibial articular geometry, and tibial post-femoral box geometry.

How have alternative bearings (such as metal-on-metal, highly cross-linked polyethylene, and ceramic-on-ceramic) affected the prevention and treatment of osteolysis?

Osteolysis is a multifactorial process dependent on surgical technique, implant design, patient factors, and material composition. Alternative bearing surfaces, such as highly cross-linked polyethylene, ceramic-on-ceramic, and metal-on-metal articular surfaces, have been introduced in an attempt to reduce wear and osteolysis following total hip arthroplasty. Intermediate-term follow-up data available suggest that the prevalence and severity of osteolysis may be reduced with these materials compared with conventional metal-on-polyethylene bearing surface couples.

The ugly underbelly of the MIS movement: in the affirmative.

Minimally invasive surgery (MIS) for hip or knee arthroplasty has been a recent rage in orthopedics. However, there are no substantial data supporting the use of these techniques, and multiple articles document increased risk of complications with MIS technique. Unfortunately, a huge marketing effort on the part of the implant industry and many surgeons is creating pressure on surgeons to sacrifice the quality of outcome for purported improved cosmesis or shorter length of hospital stay.

The optimal metal-metal arthroplasty is still a total hip arthroplasty: in the affirmative.

Metal-metal hip resurfacing offers the advantage of conservation of femoral bone stock. In addition, the implant may offer enhanced resistance to dislocation in comparison with conventional total hip arthroplasty (THA). However, early and intermediate results of the procedure do not exceed those of conventional THA.

The rationale for metal-on-metal total hip arthroplasty.

Metal-on-metal total hip arthroplasty has the longest clinical history of any of the currently used articular couples. Long-term followup of what are now considered suboptimal designs (eg, McKee Farrar, Ring, Sivash) has produced a wealth of knowledge regarding the safety and efficacy of this articular combination. Retrieval analysis of metal-on-metal total hip arthroplasty articular couples has shown wear between 1 and 5 microns per year after initial wear-in, in comparison with 100 to 200 microns per year associated with metal-on-polyethylene wear.

Limb length and stability in total hip replacement.

Limb-length restoration and maintenance during THR is the result of careful preoperative assessment and planning. Intraoperative objective measurement of limb length is critical to avoid over-lengthening. Stability of the reconstructed hip is the result of a combination of proper implant position, proper soft-tissue tension, component design, and patient education.

The infected total knee: management options.

The management of infection after total knee arthroplasty depends on the chronicity of the infection, host factors, and sensitivity of the infecting bacteria. Two-stage salvage consisting of removal of implants and cement, placement of an antibiotic spacer, and appropriate intravenous antibiotic therapy followed by reimplantation with an antibiotic-impregnated cement appears to be the predominant approach to managing this complication. The use of articulated spacers consisting of the sterilized femoral and polyethylene components with antibiotic cement allows maintenance of motion and bone stock.

Large versus small femoral heads in metal-on-metal total hip arthroplasty.

The recent resurgence of metal-on-metal total hip arthroplasty has afforded the surgeon new options in femoral head diameters that were not previously available. Reduction in the risk for dislocation and potential improvements in articular wear are the obvious advantages of large-diameter femoral heads. Total hips with larger-diameter femoral heads are more resistant to dislocation.

Outcome of hemiresurfacing in osteonecrosis of the femoral head.

Hemiresurfacing of the femoral head for treatment of osteonecrosis has been proposed as a reasonable alternative to total hip arthroplasty. The results of 59 patients with Ficat Stage III osteonecrosis done by a single surgeon are reviewed. At an average followup of 4.

Mid-term results of a polyethylene-free metal-on-metal articulation.

Beginning in December 1995, 193 patients (195 hips) were enrolled into this prospective, randomized, controlled multicenter investigational device exemption study. Ninety-eight patients (99 hips) with 46 polyethylene liners and 53 metal liners had minimum 5-year follow-up (mean, 5.7 years).

Case challenges in knee surgery: what would you do?

This case discussion features knee arthroplasty cases presented to a panel of surgeons. The cases were chosen to represent common clinical problems encountered in everyday practice.

Bone loss in total knee arthroplasty: graft augment and options.

The alternatives available for management of bone defects in total knee arthroplasty include prosthetic augments, autograft, allograft, and the use of bone cement. The selection of the augment technique should be based on the defect size, the patient age and life expectancy, and an assessment of the documented clinical results of each method. Prosthetic augments will address the vast majority of defects.