Clinical results of modular polyethylene insert exchange with retention of total knee arthroplasty components.

BACKGROUND: Modular polyethylene inserts have enabled surgeons to perform an isolated tibial insert exchange while retaining well fixed components. The purpose of this study was to review the results of insert revision and to clarify the role of this option compared with that of revision total knee arthroplasty. METHODS: Fifty-six patients (sixty-three knees) were managed with revision of a tibial polyethylene insert and retention of well aligned and stable femoral and tibial components. The implants had been in situ for an average of fifty-nine months (range, two to 108 months) at the time of the insert exchange. The inserts that were removed at the time of exchange were evaluated with regard to wear of the articular surface according to the classification system of Hood et al. and with regard to undersurface wear according to the method described by Wasielewski et al. Forty-eight knees were followed for an average of 7.4 years (range, 3.0 to 12.2 years) after the insert exchange. Knees that did not require an additional operation were considered to have had a successful exchange. RESULTS: Seven of the forty-eight exchanges failed, at an average of fifty-four months, because of accelerated wear of the new insert. All seven knees required complete revision of all components. Of the twenty-two exchanges that were performed because of severe wear of the primary insert, six (27 percent) failed at an average of less than five years; thus, knees in which the exchange was performed because of advanced wear were more likely to fail again (p < 0.05). In addition, primary inserts that were removed from knees in which the exchange procedure subsequently failed had higher delamination scores than those that were removed from knees in which the exchange was successful (p < 0.05). Most of the primary inserts had substantial undersurface wear at the time of the exchange procedure. Metallosis (thirty knees) and osteolysis (nineteen knees) were unrelated to failure of the exchange. CONCLUSIONS: An isolated revision of the tibial polyethylene insert should not be performed when there is accelerated wear of the insert with severe delamination and grade-3 or 4 undersurface wear within ten years after the primary procedure. Because a variety of patient-related, implant-related, and technical factors influence polyethylene wear, the orthopaedist must consider multiple variables whenever contemplating a limited revision.

Open reduction and internal fixation of the distal humerus: functional outcome in the elderly.

OBJECTIVE: To examine the functional outcome of a cohort of elderly patients after open reduction and internal plate and screw fixation of distal humerus fractures. DESIGN: Retrospective review of a consecutive series of patients older than 60 years of age who underwent plate and screw fixation of a distal humerus fracture. MATERIALS AND METHODS: Eighteen patients, aged 63 to 85 years (average, 71 years), underwent open reduction and internal fixation of a displaced distal humerus fracture using plates and screws. Three were Arbeitsgemeinschaft für Osteosynthesefragen/Association for the Study of Internal Fixation (AO/ASIF) type A, 2 were type B, and 13 were type C fractures. The patients were reviewed at a minimum follow-up of 1 year after surgery. MEASUREMENTS AND MAIN RESULTS: All patients had a good or excellent clinical result using a standardized method of evaluation. General health status, as measured by the SF-36 Health Survey, was comparable to the published norms for U.S. male and female populations of similar age. CONCLUSION: Open reduction and internal fixation of the distal humerus in the elderly can provide good clinical results. Good clinical results, however, do not imply good general health status.

Surgical maneuvers placing the sciatic nerve at risk during total hip arthroplasty as assessed by somatosensory evoked potential monitoring.

The sciatic nerve in 52 hip arthroplasties was evaluated using intraoperative somatosensory evoked potentials (SSEPs). Twenty-nine of these cases involved the lateral transtrochanteric approach, and 23 involved the posterior approach. A total of 11 incidents of SSEP changes occurred in eight patients. Six episodes occurred during lateral retraction of the proximal femur, and three occurred during anterior retraction of the proximal femur. Tracings returned to baseline with prompt cessation of femoral retraction in each case. One SSEP change occurred in a revision following reduction of the prosthetic components, and this resolved with shortening of the prosthetic neck to less than anatomic length. One change occurred during tightening of cables securing strut allografts to the femur and this resolved spontaneously. No correlation was found between frequency of SSEP changes and age, sex, limb lengthening, or preoperative range of motion. It is concluded that routine lateral or anterior retraction may place the sciatic nerve at risk.

Fracture-dislocation of the neck of the talus in a ten-year-old child: a case report and review of the literature.

A ten-year-old female underwent open reduction and internal fixation of a Hawkins type III fracture of the talar neck. The fracture united within three months. However, avascular necrosis of the body of the talus occurred. Partial collapse of the talar body ensued despite protection from weight-bearing for eight months after surgery. This case illustrates that fracture-dislocation of the talus can occur in a child and has a guarded prognosis.

A septic hip complicated by a ruptured appendix in an intravenous drug user.

This paper reports on a case of hip joint sepsis complicated by a ruptured appendix in an intravenous drug user. A 41-year-old woman underwent open irrigation and débridement of her right hip joint for a methicillin-sensitive Staphylococcus aureus infection. Five days later the patient developed an intraperitoneal mass, requiring laparotomy and débridement of a periappendiceal abscess. The organisms infecting the abscess were different from those infecting the patient's hip. The patient recovered satisfactorily after 6 weeks of intravenous antibiotic therapy.