Total hip and knee arthroplasty in patients with hereditary multiple exostoses.

To the authors' knowledge, few reports have been published in the English literature of using total knee arthroplasty and total hip arthroplasty for the treatment of hereditary multiple exostoses. This article describes 2 patients with hereditary multiple exostoses, 1 treated with total hip arthroplasty and 1 treated with total knee arthroplasty. Bony deformities make arthroplasty uniquely challenging in patients undergoing total hip or knee arthroplasty. An expanded metaphysis of the proximal femur, coxa valga deformity, and the presence of hardware from previous reconstructive surgeries can make total hip arthroplasty technically difficult. Substantial bony deformity of the distal femur, valgus deformity of the knee, and sizing issues that necessitate custom implants can make total knee arthroplasty difficult. The most common bony deformities in hereditary multiple exostoses are short stature, limb-length discrepancy, valgus deformity at the knee and ankle, and asymmetry of the pectoral and pelvic girdles. Most reported surgical treatments for patients with hereditary multiple exostoses focus on the pediatric population or the management of malignant transformation of exostoses. Studies that specifically address the conditions associated with knee deformities focus on extra-articular deformity correction rather than arthroplasty.When arthroplasty is necessary in this patient population, an understanding of the commonly occurring deformities can help with preoperative planning and surgical management. All painful lesions must be evaluated for malignant transformation. Bone scans can be useful during workup. All specimens should be sent for pathologic evaluation. Such patients are challenging because of the distorted hip anatomy and valgus knee deformity. The current 2 cases illustrate specific challenges that can be anticipated and underscore key principles for arthroplasty in the management of hereditary multiple exostoses.

Cementless femoral fixation in total hip arthroplasty.

A number of cementless femoral stems are associated with excellent long-term survivorship. Cementless designs differ from one another in terms of geometry and the means of obtaining initial fixation. Strict classification of stem designs is important in order to compare results among series. Loosening and thigh pain are less prevalent with modern stem designs. Stress-shielding is present in most cases, even with newer stem designs.

Outcomes of unicompartmental knee arthroplasty stratified by body mass index.

Patients who have high body mass indices can have disabling medial compartment knee osteoarthritis, which might benefit from unicompartmental knee arthroplasty (UKA). The purpose of this study was to compare clinical and radiographic outcomes of UKAs in patients with body mass indices (BMIs) greater and less than 35 kg/m(2). Thirty-four patients (40 knees) had BMIs of 35 kg/m(2) or greater, whereas the remaining 33 patients (40 knees) had BMIs below 35 kg/m(2), with 2-year minimum follow-up. In the high-BMI group, 5 knees were revised to total knee arthroplasty, compared with none in the lower BMI group. Knee Society scores were lower in the surviving high-BMI knees. All surviving components were radiographically stable. The results suggest that UKA should be approached with caution in patients who have high BMIs.

Chronic expanding hematoma of the lateral thigh and massive bony destruction after a failed total hip arthroplasty.

Pseudotumors have been described around both stable and failed total hip arthroplasties. The causes are varied and include polyethylene debris and masses associated with metal-on-metal bearings. We present a patient with a massive tumor of the thigh that grossly and pathologically was associated with recurrent bleeding and extensive bony destruction. The characteristics of this tumor most resemble those of a chronic expanding hematoma. To our knowledge, this has not previously been reported in association with a total hip arthroplasty.

Atraumatic bilateral femur fracture in long-term bisphosphonate use.

Postmenopausal women with osteoporosis are commonly treated with the bisphosphonate class of medications, one of the most frequently prescribed medications in the United States. In the past 4 years, reports have been published implying that long-term bisphosphonate therapy could be linked to atraumatic femoral diaphyseal fractures. This article presents a case of a 67-year-old woman who presented with an atraumatic right femur fracture. She had a medical history notable for use of the bisphosphonate alendronate for 16 years before being switched to ibandronate for 1 year before presentation. She had sustained a similar fracture on the contralateral side 3 years previously. This case report, in addition to a review of the literature, shows that use of the bisphosphonate class of medications for an extended period of time may result in an increased susceptibility to atraumatic femoral diaphyseal fractures. Some studies have suggested that the reason may be the mechanism of action of bisphosphonates, resulting in decreased bone turnover and remodeling. Studies have not shown if the entire class of medications produce a similar result, but patients who have been treated with any bisphosphonate for an extended period of time should be considered at risk. In patients who have already sustained a femoral diaphyseal fracture, imaging of the contralateral side should be performed to identify cortical thickening as an early sign of fracture risk. Patients should also be questioned about thigh pain.