Normal postoperative febrile response in the pediatric orthopaedic population.

Postoperative fever in the pediatric orthopaedic population remains a clinical concern even though prior studies concluded that fevers are a poor predictor of surgical complications. In this retrospective study of 177 patients, we established guidelines regarding the degree and time course of fever we should expect based on the perioperative conditions of magnitude of surgery, duration of surgery, need for intraoperative transfusion, estimated blood loss, age, and gender. To provide a more sensitive assessment of fever, we developed composite temperature curves for each patient and defined the area under these curves as the total febrile response (TFR). This allowed us to assess fever as a cumulative event, taking into account both its magnitude and duration. A multivariate model then determined that of the perioperative conditions studied, intraoperative transfusion status and estimated blood loss were most helpful in predicting a patient's TFR. The results of this study can be used as an additional tool for assessing postoperative progress and whether a fever is within the normal limits indicated by a patient's perioperative variables.

Clinical comparison of all-polyethylene and metal-backed tibial components in total knee arthroplasty.

Based primarily on in vitro biomechanical studies, most total knee arthroplasty (TKA) manufacturers have abandoned the all-polyethylene tibial component (APT) in favor of the metal-backed tibial component (MBT). There is little clinical evidence to support this decision. A retrospective review of cemented TKA using the total condylar prosthesis was performed. One hundred eighteen patients with 131 TKAs were evaluated. Sixty-two of these knee prostheses had tibial components made entirely of polyethylene while 69 had the MBT. There were 13 cases of bilateral TKA in which the APT was used for one knee and the MBT for the other. All patients were examined by the authors for an average follow-up period of six years. Hospital for Special Surgery knee scores and a comprehensive roentgenographic evaluation were obtained. No significant difference was noted between the patients with APT and those with MBT, raising serious doubt on the need for the MBT in patients being treated with primary, cemented TKA.

Avoiding paraplegia during anterior spinal surgery. The role of somatosensory evoked potential monitoring with temporary occlusion of segmental spinal arteries.

Three patients paraplegic following anterior spinal fusion for congenital kyphoscoliosis were noted to have complete somatosensory evoked potential signal loss shortly after segmental arterial ligations at the apex of their respective kyphosis. This has prompted us to use temporary segmental arterial occlusion with somatosensory evoked potential monitoring prior to ligation during anterior spinal fusion. As a result, we have noted seven additional cases, out of a total of 44 cases monitored in this fashion, in which complete loss of somatosensory evoked potential signals, reversible by release of vascular clips, has occurred. For each of these additional cases the critical segmental arteries were identified and were not ligated, usually resulting in some modifications in the planned surgical procedure, and the patients remained neurologically intact. We recommend temporary segmental arterial occlusion with somatosensory evoked potential monitoring during thoracolumbar anterior spinal fusion to potentially avert ischemic neurologic injury. Based on published data and the experience described herein, this technique should be especially important in anterior spinal fusion for congenital kyphoscoliosis.

Measurement of femoral head microcirculation by laser Doppler flowmetry.

Perfusion of the capital femoral epiphysis was measured by laser Doppler flowmetry (LDF) in a series of skeletally immature pigs. After induction of balanced general anesthesia, selective occlusion of the arterial blood supply to the hip was performed with continuous monitoring by a laser Doppler probe applied to the articular surface of the femoral head. The lateral femoral circumflex artery, a main branch of the superficial femoral artery in the pig, was largely responsible for femoral head perfusion in eight of nine pigs, according to LDF measurements. This finding was confirmed by postmortem silicone rubber injections and Spalteholz preparations of the femoral heads.

Skeletal disorders in a pediatric renal transplant population.

Relatively little is known about the incidence of musculoskeletal disorders in patients with chronic renal failure, the conditions that give rise to particular types of deformities, and indications for operative management. Two selected patient pools were evaluated for the presence of disorders commonly seen in these patients: bony deformity, epiphysiolysis, and osteonecrosis. Relationships were noted between the occurrence of these abnormalities and age at diagnosis of renal failure, the patient's age at the appearance of the disorder, and age at time of renal transplantation. Recognition of such patterns and relationships should be helpful in earlier identification and management of these disorders.

Axial loading studies of unstable intertrochanteric fractures of the femur.

An experimental four-part unstable intertrochanteric (IT) femoral fracture was created with either a large or small posteromedial fragment (PMF). Sixty-eight adult embalmed femoral anatomic specimens were fractured and subjected to axial loading after fixation. The maximum load prior to failure for femora from the same anatomic specimen was compared to differentiate between different methods of fixation. In the presence of the large PMF variation, anatomic reduction and fixation allowed the femur to resist an average maximum load 57% greater than identical fractures with the fragment excluded. Fixation of the small PMF increased construct strength by an average of 17% over no fixation. The PMF is the keystone to mechanical stability for IT fractures of the femur. When anatomic reduction is possible, its fixation becomes progressively more critical as its size increases.

Hip fracture in a heart transplant patient.

The considerable risks of osteonecroses and fractures after renal transplantation are well described. Whether or not these transplantation risks are unique to those with renal failure is uncertain. A 56-year-old man developed multiple spontaneous fractures, including a fracture of the femoral neck, following cardiac transplantation.

Threaded cup acetabuloplasty. Early clinical experience.

Loosening of the acetabular cup component in total hip arthroplasty (THA) remains a source of ongoing concern. Threaded cup acetabuloplasty (TCA) utilizes torque and compression to gain purchase of the acetabular cup into the bony margin of the acetabulum. In an earlier study of 121 patients who had THA with TCA, patient assessments and roentgenograms were examined at an average of 30 months after surgery. Twenty percent of the cases were carried out for failed arthroplasty and 20% of the procedures required bone-graft reconstruction. A 22% incidence of moderate to severe postoperative pain, a 3% incidence of cup dislodgement, and a 24% incidence of radiolucencies between 1-2 mm were observed. The four cup dislodgements occurred in patients with severe osteopenia or in those requiring extensive bone-graft acetabular reconstruction. Good clinical results were obtained for osteoarthritic patients treated with primary THA. These early findings suggest that there is no advantage, but there are possible disadvantages, to threaded cup acetabuloplasty when compared to cup fixation with cement.

Symptomatic spondylolisthesis in adults: four decades later.

An average follow-up of 40 years was obtained for 12 patients with spondylolisthesis treated at Hines Veterans Administration Hospital between 1944 and 1951. In each case, the slip had been Grade 1 and at the L5-S1 level. Five had been treated conservatively and seven surgically with a Hibbs fusion from L4 to S1. Of the conservatively managed patients, all functioned well during their working years, although one did have chronic, nondisabling, low-back pain. This same patient demonstrated radiographic evidence of progression to a Grade 2 spondylolisthesis. Among those undergoing surgery, the poor results were confined to those patients whose fusion attempts failed. Management for low-grade spondylolisthesis should be conservative where possible. When the low-back pain is disabling and surgery becomes necessary, failure to obtain a fusion portends a poor clinical result.

Flexible intramedullary nails for ipsilateral femoral and tibial fractures.

Between June 1981 and August 1983, six patients were treated with flexible intramedullary nails for both femoral and tibial fractures in six floating knees. All six patients were males averaging 26 years of age and all six were involved in motor vehicle accidents. Concomitant associated injuries were common. Two femoral and five tibial fractures were open. All fractures were stabilized within 24 hours of injury by closed intramedullary nailing with Ender nails. At final followup, there was one femoral and one tibial nonunion in the same patient. For the remaining patients, femoral union averaged 10.3 weeks and tibial union averaged 18 weeks. Five patients regained full motion at the hip, and four regained full motion at the knee and ankle. Four patients returned to their preinjury level of function; two were less active, one ambulating without the use of external assistive devices, and one using a cane.