Inflammatory pseudotumor complicating metal-on-highly cross-linked polyethylene total hip arthroplasty.

Inflammatory masses or cysts occurring in the pelvis, thigh, and gluteal regions, often mimicking infection, occasionally arise after total hip arthroplasty procedures. Inflammatory pseudotumors comprise a subgroup of these lesions. Pseudotumors have been associated with pain, rashes, instability, neuropathy, and premature loosening of prosthetic components, often leading to early and difficult revision surgery. The association between such pseudotumors and metal-on-metal bearings has led to questions regarding the performance of these bearings in hip arthroplasty. We present a case of pseudotumor requiring revision surgery, which occurred uniquely around a metal-on-highly cross-linked polyethylene bearing.

Femoral head size does not affect ion values in metal-on-metal total hips.

BACKGROUND: Metal-on-metal articulations can release substantial amounts of particles containing cobalt and chromium into the surrounding milieu, causing concern for cellular toxicity and adverse local soft tissue reactions. The diameter of the femoral head has been one of the variables that inversely affects wear of metal-on-metal total hip arthroplasty (THA). The oxidative stress of increased metal ions can be measured with serum markers. It is still controversial if larger femoral head diameters decrease wear rates in patients with metal-on-metal THA and if the increased metal ions alter the body's antioxidant status. QUESTIONS/PURPOSES: We therefore (1) determined whole blood metal ions in patients with small (28 mm and 36 mm) and large (40 mm and 44 mm) diameter femoral heads; (2) measured oxidative stress markers (total antioxidants, nitrotyrosine, and peroxides); and (3) determined whether acetabular version or inclination influenced ion levels. METHODS: One hundred four patients were retrospectively studied. We recorded Harris hip scores and UCLA activity scores. All patients were followed at 1 year. RESULTS: The activity scores were similar in the two groups. There was no difference in metal ion levels or oxidative stress markers between patients with small- or large-diameter femoral heads. Acetabular inclination and anteversion had no effect on the metal ion levels. CONCLUSIONS: The data suggest there is no difference in ion values in patients with large or small metal-on-metal THA and the increased metal ions do not alter the oxidant status of the patient.

Suture-endobutton fixation of ankle tibio-fibular diastasis: a cadaver study.

Suture-Endobutton fixation is proposed as a minimally invasive, flexible fixation of ankle tibio-fibular diastasis, which would not require routine removal. This study tested the Suture-Endobutton construct in a cadaver syndesmosis injury model and compared this against A.O. syndesmosis screw fixation. Sixteen embalmed cadaver legs were used. Phase one consisted of placing the leg in a jig, generating an external rotation torque and measuring diastasis with increasing intraosseous membrane division. Phase two then compared the Suture-Endobutton construct vs. single four-cortex 4.5 mm A.O. screw fixation. Diastasis increased significantly with increasing intraosseous membrane division (p<0.001). No significant differences were seen in the mean rate of failure between the Suture-Endobutton and A.O. screw fixation. However, the Suture-Endobutton did give a significantly more consistent performance; the distribution of standard deviations for A.O. screw fixation was 0.64 mm higher than that for the Endobutton (95% C.I. 0.46 to 0.84). These results show that Suture-Endobutton fixation at least equals the performance of screw fixation and encourages clinical trials in ankle injuries with a syndesmosis diastasis.

An unusual orthopaedic presentation of acute lymphoblastic leukemia.

A 3-year-old boy of Romanian origin was admitted with the inability to weight bear and pyrexia. He was investigated to rule out septic arthritis. He subsequently developed an atypical clinical picture of fleeting joint arthritis, spiking temperature with poor response to antibiotics and atypical results of investigations. The peripheral blood smear showed a normal leukocyte count, but evidence of blast cells. Bone marrow aspirate confirmed the diagnosis of acute lymphoblastic leukemia. His skeletal radiographic survey had shown evidence of symmetrical metaphyseal sclerosis in the long bones, which has not been previously described as an isolated feature of acute lymphoblastic leukemia. Following a good response to chemotherapy, partial resolution of the sclerosis occurred. This case illustrates that metaphyseal sclerosis can be one of the manifestations of acute lymphoblastic leukemia and delay in diagnosis can easily occur in the absence of classic features of the disease. An early diagnosis is a good prognostic feature of these childhood malignancies.

The evaluation of the inverted supinator reflex in asymptomatic patients.

STUDY DESIGN: A prospective study was undertaken over a 6-month period to determine the incidence of the inverted supinator reflex in asymptomatic, neurologically normal individuals. OBJECTIVE: The objective of our study is to assess asymptomatic patients for the presence of the inverted radial reflex and to determine its clinical relevance. SUMMARY OF BACKGROUND DATA: The inverted radial reflex sign is commonly used in clinical practice to assess cervical myelopathy. It is unknown whether the sign correlates with the presence or severity of myelopathy, and no consensus exists regarding the significance of a positive sign in asymptomatic individuals. METHODS: Patients attending the Trauma Clinic at our institution were invited to participate. Each patient was examined neurologically and specifically for the presence or absence of the Babinski test, Hoffman's sign, the finger escape sign, static and dynamic Romberg's test, and the inverted supinator reflex. Patients were excluded if they had any history of neck pain, any history of neurosurgical procedure or spinal surgery, any known neurologic disorder or deficit, or if there was any outstanding medicolegal case. RESULTS: We examined 277 patients in 6-month period. The male to female ratio was 1.1:1. The mean age was 27 years (range, 16-78). The incidence of the inverted supinator reflex was 27.6% (75/271). Of the 75 positive patients, the inverted supinator reflex was present bilaterally in 39% (29/75). Nine of 75 patients (10%) had an associated positive Hoffman's sign but had no other signs suggestive of myelopathy. The proportion of patients with a positive inverted supinator reflex reduced with increasing age (Pearson correlation coefficient > 0.80). CONCLUSION: This study demonstrates that an isolated, inverted supinator reflex may be a variation of normal clinical examination. We believe that an isolated inverted supinator reflex, in the absence of other clinical findings, is not a reliable sign of cervical myelopathy; however, it must be interpreted with caution in the older patient.

Short segment posterior locking cervical plate fixation after kyphectomy for myelomeningocoele-associated kyphosis.

We report the use of posterior cervical locking plate fixation after apical vertebral excision for congenital lumbar kyphosis in a 3-year-old male myelomeningocoele patient. At 4-year follow-up the fixation was secure and the correction was well preserved.