Total hip replacement for the treatment of acute femoral neck fractures: results from the National Joint Registry of England and Wales at 3-5 years after surgery.

INTRODUCTION: This paper describes, for the first time, the outcomes of patients undergoing total hip replacement for acute fractured neck of femur (#NOF) as recorded by the National Joint Registry of England and Wales (NJR). METHODS: In the NJR we identified 1,302 of 157,232 Hospital Episode Statistics linked patients who had been recorded as having a total hip replacement for acute #NOF between April 2003 and November 2008. RESULTS: The revision rate at five years for fully uncemented components was 4.1% (95% confidence interval [CI]: 2.2-7.3%), for hybrid it was 2.2% (95% CI: 0.9%-5.3%) and for fully cemented components 0.9% (95% CI: 0.4-2.0%). Five-year revision rates were increased for those whose operations were performed via a posterior versus a lateral approach. The Kaplan-Meier estimate of 30-day mortality was 1.4% (95% CI: 1.0-2.4%), which is over double the 30-day mortality rate for total hip replacement identified by the Office for National Statistics. The mean length of stay was also increased for those undergoing total hip replacements for #NOF compared with non-emergency indications. CONCLUSIONS: Our data suggest that total hip replacements for acute #NOF give comparable results with total hip replacements for other indications.

Early failure of the Ultima metal-on-metal total hip replacement in the presence of normal plain radiographs.

Metal-on-metal total hip replacement has been targeted at younger patients with anticipated long-term survival, but the effect of the production of metal ions is a concern because of their possible toxicity to cells. We have reviewed the results of the use of the Ultima hybrid metal-on-metal total hip replacement, with a cemented polished tapered femoral component with a 28 mm diameter and a cobalt-chrome (CoCr) modular head, articulating with a 28 mm CoCr acetabular bearing surface secured in a titanium alloy uncemented shell. Between 1997 and 2004, 545 patients with 652 affected hips underwent replacement using this system. Up to 31 January 2008, 90 (13.8%) hips in 82 patients had been revised. Pain was the sole reason for revision in 44 hips (48.9%) of which 35 had normal plain radiographs. Peri-prosthetic fractures occurred in 17 hips (18.9%) with early dislocation in three (3.3%) and late dislocation in 16 (17.8%). Infection was found in nine hips (10.0%). At operation, a range of changes was noted including cavities containing cloudy fluid under pressure, necrotic soft tissues with avulsed tendons and denuded osteonecrotic upper femora. Corrosion was frequently observed on the retrieved cemented part of the femoral component. Typically, the peri-operative findings confirmed those found on pre-operative metal artefact reduction sequence MRI and histological examination showed severe necrosis. Metal artefact reduction sequence MRI proved to be useful when investigating these patients with pain in the absence of adverse plain radiological features.

MRI of early symptomatic metal-on-metal total hip arthroplasty: a retrospective review of radiological findings in 20 hips.

AIM: To perform a retrospective review of all the conventional radiographic and magnetic resonance imaging (MRI) studies performed in patients with early postoperative pain following cobalt-chrome metal-on-metal total hip arthroplasty. METHODS: A retrospective review of the radiology, surgical findings and histology in nineteen patients who had undergone a total of 20 hip arthroplasties using a cobalt-chromium on cobalt-chromium alloy prosthesis was undertaken. RESULTS: Measures of implant placement on the immediate postoperative radiographs were all within the normal ranges (n=20). Where more than one postoperative radiograph was available statistical analysis revealed no evidence of progressive change before the MRI examination (14). The median postoperative time to MRI was 35 months (range 11-63 months). Abnormalities were demonstrated using MRI in all symptomatic hips (n=20). These comprised: periprosthetic fluid collections (20), which were isointense to muscle on T1-weighted images in 19 cases and hyperintense on T2-weighted images in 18 cases, periprosthetic bone marrow oedema (n=6), muscle oedema (n=4), avulsion of the gluteus minimus and medius tendons (n=5), atrophy of piriformis (n=15) and obturator internus (n=17), and fracture of the medial calcar (n=1). Operative findings in patients who had undergone revision surgery (n=15) included: fluid-filled cavities (n=11), soft tissue necrosis (n=8), gluteal tendon avulsion (n=5), proximal femoral diaphyseal necrosis (n=4), and pitting and corrosion of the femoral stems (n=8), which were, in all cases, firmly fixed to the cement mantle. Histology revealed viable tissue in six hips with necrosis (n=12) and fibrin deposition (n=15) being the predominate findings. Other findings included a perivascular lymphocytic infiltrate (n=5), features of active inflammation (n=4), and metallosis (n=1). CONCLUSION: A significant number of patients with metal-on-metal hip replacements presented with early postoperative pain because of an abnormal soft-tissue reaction. MRI can demonstrate characteristic soft-tissue disease in these patients where conventional radiographs are frequently normal.

Autobanking of femoral heads for revision total hip replacement, a preliminary report of a new surgical technique.

BACKGROUND AND AIM: Conventional banking of bone allografts has been well documented in the literature. It relies on standardised screening and providing a sterile storage facility. We report a new surgical technique of banking the femoral head in a surgically fashioned subperiosteal iliac pouch and its use for the donor's own surgery. MATERIAL AND METHODS: Thirteen patients with an average age of 60 years and a diagnosis of osteoarthritis of the hip with a contralateral symptomatic loose hip replacement were selected. The femoral head was harvested and banked. On retrieval, histological analysis was performed in four specimens with clinical and radiographic review of all subjects. RESULTS: Radiographic results show good integration of the morselised femoral head bone graft in revision hip surgery. Histological results from four retrieved specimens show viability at eight years and eleven months from insertion into the pouch. DISCUSSION: Autobanking of the patient's own femoral head is suitable in a select group of patients in whom a combined primary and contralateral revision total hip replacement poses an unacceptable anaesthetic risk. It has the advantage of providing a graft with osteoinductive potential and a reduced risk of infection. It eliminates the need for a storage facility and screening programme. It also provides a portable storage facility if the patient moves elsewhere.

Disseminated osteosarcoma arising in the pelvis after total hip arthroplasty.

The development locally of a malignant neoplasm after total hip arthroplasty is rare but increasingly recognized. Its significance is unclear. The association could be fortuitous. If not, the rarity of the complication argues that constitutional factors are likely to be important in pathogenesis. We describe a case of disseminated osteosarcoma of the hip developing 6.5 years after total hip arthroplasty and review the related literature.

The value of MRI in the assessment of an elbow injury in a neonate.

We describe the use of MRI to establish the exact diagnosis in a swollen elbow in a neonate. Urgent diagnosis was needed for medical and social reasons. We accomplished this without the use of an invasive procedure or anaesthesia for a fracture that is recognised to be difficult to diagnose in patients of this age group.

The role of the integument as a barrier to penetration of ice into overwintering hatchlings of the painted turtle (Chrysemys picta).

Hatchlings of the North American painted turtle (Chrysemys picta) spend their first winter of life inside a shallow, subterranean hibernaculum (the natal nest) where they may be exposed for extended periods to ice and cold. Hatchlings seemingly survive exposure to such conditions by becoming supercooled (i.e., by remaining unfrozen at temperatures below the equilibrium freezing point for body fluids), so we investigated the role of their integument in preventing ice from penetrating into body compartments from surrounding soil. We first showed that hatchlings whose epidermis has been damaged are more likely to be penetrated by growing crystals of ice than are turtles whose cutaneous barrier is intact. We next studied integument from a forelimb by light microscopy and discovered that the basal part of the alpha-keratin layer of the epidermis contains a dense layer of lipid. Skin from the forelimb of other neonatal turtles lacks such a layer of lipid in the epidermis, and these other turtles also are highly susceptible to inoculative freezing. Moreover, epidermis from the neck of hatchling painted turtles lacks the lipid layer, and this region of the skin is readily penetrated by growing crystals of ice. We therefore conclude that the resistance to inoculation imposed by skin on the limbs of hatchling painted turtles results from the presence of lipids in the alpha-keratin layer of the epidermis. Neonates apparently are able to avoid freezing during winter by drawing much of the body inside the shell, leaving only the ice-resistant integument of the limbs exposed to ice in the environment. The combination of behavior and skin morphology enables overwintering hatchlings to exploit an adaptive strategy based on supercooling.

Intermittent clamping of suction drains in total hip replacement reduces postoperative blood loss: a randomized, controlled trial.

A randomized, controlled study of 54 patients (28 patients in the trial and 26 in the control group) who had primary total hip replacement was carried out. The 2 suction drains were clamped intermittently 55 minutes in each hour and released for 5 minutes in each hour for 6 hours postoperatively in the trial group. Free drainage was allowed in the control group. The difference in calculated total blood loss was significantly less in the trial group than in the control group (P < .05). Patients in the trial group received 13 fewer blood transfusions than the control group. No difference in wound drainage and wound healing was noted. Using ultrasound, it was also shown that the technique did not lead to hematoma formation.

Endogenous yolk steroid hormones in turtles with different sex-determining mechanisms.

Maternal transfer of nutrients, including steroid hormones, to embryos during gestation in viviparous amniotes is well known, but the concordant process in oviparous amniotes is poorly understood. Recent evidence suggests that steroid hormones are present in freshly laid eggs of archosaurs and that their concentrations may influence offspring phenotypes. This process might be especially important in reptiles with temperature-dependent sex determination (TSD), because embryonic sex determination as well as other traits is thought to be influenced by temperature-dependent steroid metabolism. To evaluate the potential importance of endogenous steroid hormones to developing reptilian embryos, we (1) measured testosterone and estradiol-17beta levels in fresh eggs from natural populations of three species of turtles with TSD and two with genotypic sex determination (GSD), (2) evaluated testosterone concentrations within and among clutches of two turtle species with TSD, and (3) correlated clutch testosterone concentrations with incubation length, body mass, and sex ratio of offspring of two turtle species with TSD from eggs incubated at pivotal sex-determining temperatures. Turtles with TSD had higher levels of yolk testosterone (up to approximately 300 ng/g) than turtles with GSD (up to approximately 15 ng/g), suggesting a potential functional dichotomy between these two classes of sex-determining mechanisms; concentrations of yolk estradiol-17beta were low and fairly uniform among all five species (approximately 1 ng/g). Yolk testosterone varied substantially among, and relatively little within, clutches, indicating considerable potential as a mechanism behind clutch effects on offspring phenotypes. Steroid concentrations were unrelated to order of oviposition, unlike in birds, but yolk testosterone levels were correlated with incubation length and possibly with offspring sex ratio. Embryos of Chelydra serpentina serpentina from clutches with higher yolk testosterone hatched soonest at 21.8 degreesC; the opposite was true for Trachemys scripta elegans embryos incubated at 28.2 degreesC. At 27.6 degreesC, C. s. serpentina clutches with higher yolk testosterone produced more male-biased offspring sex ratios. Taken together, these results are strikingly consistent with published data on other oviparous amniotes and with the known physiology of follicular development and embryonic sexual differentiation in these disparate taxa. The findings of these experiments suggest that yolk testosterone in turtle eggs may be biologically significant.

Cloning and functional studies of splice variants of the alpha-subunit of the amiloride-sensitive Na+ channel.

The alpha-subunit of the amiloride-sensitive epithelial Na+ channel (alpha ENaC) is critical in forming an ion conductive pore in the membrane. We have identified the wild-type and three splice variants of the human alpha ENaC (h alpha ENaC) from the human lung cell line H441, using RT-PCR. These splice variants contain various structures in the extracellular domain, resulting in premature truncation (h alpha ENaCx), 19-amino acid deletion (h alpha ENaC-19), and 22-amino acid insertion (h alpha ENaC + 22). Wild-type h alpha ENaC and splice variants were functionally characterized in Xenopus oocytes by coexpression with hENaC beta- and gamma-subunits. Unlike wild-type h alpha ENaC, undetectable or substantially reduced amiloride-sensitive currents were observed in oocytes expressing these splice variants. Wild-type h alpha ENaC was the most abundantly expressed h alpha ENaC mRNA species in all tissues in which its expression was detected. These findings indicate that the extracellular domain is important to generate structural and functional diversity of h alpha ENaC and that alternative splicing may play a role in regulating hENaC activity.

Gender-related differences in the amount and functional state of rat liver UDP-glucuronosyltransferase.

The basis for gender-dependent differences in rates of glucuronidation of xenobiotics is uncertain. To clarify this issue, the glucuronidation of p-nitrophenol was compared in liver microsomes from adult male and female rats. The activity of native UDP-glucuronosyltransferase was 47% higher in microsomes from male than from female rats. Immunoblotting of microsomal protein with anti-UDP-glucuronosyltransferase antiserum revealed 66% more immunoreactive protein in male microsomes. A kinetic method for measuring glucuronidating enzyme content confirmed the result of the immunoblot. Responses of UDP-glucuronosyltransferase to activation by palmitoyllysophosphatidylcholine or high pressure indicated that the activity of the enzyme was more latent in male than in female microsomes. Differences in enzyme latency could be due to differences in membrane structure. A comparison of microsomal fatty acid composition revealed significantly higher levels of oleic and linoleic acids and lower levels of stearic and docosahexaenoic acids in male than in female microsomes. The phospholipid composition, ratio of cholesterol:phospholipid, and membrane fluidity were similar in male and female microsomes. These results indicate that gender-dependent differences in UDP-glucuronosyltransferase activity are due to differences in both the amount and functional state of the enzyme.

Radiographic appearances in lumbar disc prolapse.

The pre-operative lumbar spine radiographs of 200 consecutive patients who had undergone discectomy for prolapsed intervertebral disc were reviewed. Prolapse was recognized as bulging or sequestration of the disc with consequent root compromise. Measurement of the lumbar level of the interiliac line was shown to correlate with the level of disc prolapse and the incidence of transitional vertebrae at the lumbosacral junction was significantly higher than normal. A pathological value for the lumbosacral angle could not be identified.

Traumatic intraperitoneal haemorrhage. Diagnosis by paracentesis and lavage.

A method is described for detecting blood in the peritoneal cavity in cases of blunt abdominal trauma. It involves introducing a peritoneal dialysis catheter through a single puncture site in the anterior abdominal wall and in some cases performing lavage. Fifty cases have been investigated by this method and the results are presented.