Retrieval analysis of porous-coated components for total knee arthroplasty. A report of two cases

Retrieval analysis of two total knee replacements incorporating porous-coated components for biologic fixation was performed. The significant finding in a 63-year-old woman was fracture of the porous-coated metal backing of the tibial component, secondary to aseptic loosening. The significant findings at the time of revision surgery in an 82-year-old woman were nonuniform bone ingrowth (primarily around fixation pegs) and fracture of metal beads from the metal backing of the patellar component.     

Bone graft for tibial defects in total knee arthroplasty

Twenty-four knees with bone grafts for tibial defects at the time of either primary or revision total knee arthroplasty were followed for three to six years. With 22 of 24 bone grafts, union and revascularization were seen and no clinical collapse was present. In two, nonunion occurred, accompanied by collapse in one. Failure was attributed to varus alignment of the leg in one (a medial condylar graft) and to insufficient preparation of the bony bed in the second (bleeding bone was not exposed). Evidence for incorporation of the grafts was obtained by tomogram, bone scan, and bone biopsy. Incorporation was present by six months, but the time to complete remodeling was not determined. A bone graft is recommended for tibial defect involving 50% or more of the bony support of either tibial plateau. A bone graft is indicated whenever a cement column under the prosthesis would measure more than 5 mm in height.     

Effect of posterior cruciate sacrifice on durability of the cement-bone interface. A nine-year survivorship study of 100 total condylar knee arthroplasties

This article presents a survivorship analysis of the second conservative 100 primary total-condylar knee arthroplasties in 75 patients performed between 1979 and 1980, with a maximum follow-up of 9 years. With this type of knee arthroplasty, the posterior cruciate ligament is routinely sacrificed. Survivorship results revealed that 98.9 per cent of the knees had good outcome at 9 years of follow-up, using revision surgery for aseptic and septic loosening and radiographic evidence of global radiolucency or shift of the component as endpoint. Radiographic survivorship analysis showed well-fixed components in 87 per cent of implants, using endpoint criteria of appearance and progression of radiolucency under tibial component. Sacrificing the posterior cruciate ligament does not adversely affect durability of fixation of the total-condylar knee arthroplasty. Bone cement provides an excellent fixation of total knee implant.     

Trispherical total wrist arthroplasty in rheumatoid arthritis

Thirty-four patients, with 35 trispherical total wrist arthroplasties for treatment of rheumatoid arthritis, were evaluated at an average follow-up of 9 years (range, 5 to 11 years). The average preoperative score was 25 points inasmuch as all patients had severe pain and loss of function. The average postoperative score improved to 87 points since 30 wrists were free of pain. Twenty-eight wrists rated as a good-to-excellent result. The average arc of flexion and extension improved from 35 to 50 degrees. There were no deep infections or dislocations. Two wrists required revision, one for loosening and one for persistent pain, both requiring removal of the implant and arthrodesis. Postoperative tendon attrition occurred in six wrists, all of which had preoperative tendon ruptures necessitating tendon transfer. Radiographs showed radiolucencies in seven wrists, including seven around the metacarpal stem and one around the radial stem. The optimum results were achieved in those patients with intact extensor tendons before operation.     

Total hip arthroplasty in rheumatoid arthritis. A long-term follow-up study

This study was undertaken to assess the clinical and radiographic results of total hip arthroplasty in rheumatoid arthritis patients with a minimum of 10 years of follow-up evaluation. Eighty-three hips in 51 of the original 104 patients were available for follow-up study an average of 12.1 years following surgery. The average age of the patients at the time of surgery was 39.9 years (range, 14-72 years). Fourteen hips were revised, 11 for mechanical loosening and 3 for late infection. The overall revision rate is 16.7%; the revision rate for mechanical loosening was 13.3%. According to Merle D'Aubigne-Postel hip rating scores in the 69 hips that did not require revision, 19 hips were excellent (28%), 37 were good (54%), 11 were fair (15%), and 2 were poor (3%). Therefore, 67 of 83 hips (80.7%) were satisfactory on follow-up study. Radiographic evidence of loosening in nonrevised hips was found in 11 acetabular and 2 femoral components.     

Role of bone grafting in correction of protrusio acetabuli by total hip arthroplasty

A study of 27 hip arthroplasties derived from a pool of more than 200 total hip arthroplasties performed between 1976 and 1981 was conducted to assess the need for and benefits of bone grafting in the surgical management of protrusio acetabuli. The objective of surgery and the reason for augmentation by bone graft was to lateralize the acetabular component, normalize the center of rotation of the hip, and strengthen the deficient medial wall. Based on this study, the authors recommend: when protrusion is less than 5 mm in either direction and the medial wall is reasonably strong, bone graft is not indicated; in protrusion greater than 5 mm with a thin but intact medial wall, autogenous bone graft is indicated but artificial fixation devices need not be used; and a grossly deficient medial wall requires reconstruction with bone graft and additional fixation devices to achieve normalization of the center of rotation of the hip joint.     

Randomized trial of hypotensive epidural anesthesia in older adults.

BACKGROUND: Data are sparse on the incidence of postoperative cognitive, cardiac, and renal complications after deliberate hypotensive anesthesia in elderly patients. METHODS: This randomized, controlled clinical trial included 235 older adults with comorbid medical illnesses undergoing elective primary total hip replacement with epidural anesthesia. The patients were randomly assigned to one of two levels of intraoperative mean arterial blood pressure management: either to a markedly hypotensive mean arterial blood pressure range of 45-55 mmHg or to a less hypotensive range of 55-70 mmHg. Cognitive outcome was assessed by within-patient change on 10 neuropsychologic tests assessing memory, psychomotor, and language skills from before surgery to 1 week and 4 months after surgery. Prospective standardized surveillance was performed for cardiovascular and renal outcomes, delirium, thromboembolism, and blood loss and replacement. RESULTS: The two groups were similar at baseline in terms of age (mean, 72 yr), sex (50% women), comorbid conditions, and cognitive function. After operation, no significant differences in the incidence of early or long-term cognitive dysfunction were observed between the two blood pressure management groups. There were no significant differences in the rates of other adverse consequences, including cardiac, renal, and thromboembolic complications. In addition, no differences occurred in the duration of surgery, intraoperative estimated blood loss, or transfusion rates. CONCLUSIONS: Elderly patients can safely receive controlled hypotensive epidural anesthesia with this protocol. There was no evidence of greater risks, or early benefits, with the use of the more markedly hypotensive range.     

Stem length in revision total knee arthroplasty

Stems are intramedullary extensions of either the femoral or tibial component of a total knee arthroplasty (TKA) designed to increase the mechanical stability to decrease the risk of aseptic loosening. Biomechanical studies have shown that TKA stems increase the mechanical stability by transferring load over a larger area and thereby reduce strain at the bone-component interface [1–4]. The length of a revision TKA stem is determined by the patient’s anatomy and the intended fixation, namely fully cemented or press-fit cortical contact. The advantages and disadvantages of various stem lengths must be weighed against the needs of the patient to achieve an optimal outcome.