Rapid evolution of elaborate male coloration is driven by visual system in Australian fairy-wrens (Maluridae).

The interplay between colour vision and animal signalling is of keen interest to behavioural ecologists and evolutionary biologists alike, but is difficult to address in terrestrial animals. Unlike most avian lineages, in which colour vision is relatively invariant among species, the fairy-wrens and allies (Maluridae) show a recent gain of ultraviolet sensitivity (UVS). Here, we compare the rates of colour evolution on 11 patches for males and females across Maluridae in the context of their visual system. We measured reflectance spectra for 24 species, estimating five vision-independent colour metrics as well as metrics of colour contrast among patches and sexual dichromatism in a receiver-neutral colour space. We fit Brownian motion (BM) and Ornstein-Uhlenbeck (OU) models to estimate evolutionary rates for these metrics and to test whether male coloration, female coloration or dichromatism was driven by selective regimes defined by visual system or geography. We found that in general male coloration evolved rapidly in comparison with females. Male colour contrast was strongly correlated with visual system and expanded greatly in UVS lineages, whereas female coloration was weakly associated with geography (Australia vs. Papua New Guinea). These results suggest that dichromatism has evolved in Maluridae as males and females evolve at different rates, and are driven by different selection pressures.

Faithful females receive more help: the extent of male parental care during incubation in relation to extra-pair paternity in songbirds.

Parental care provided by males occurs in a diverse array of animals and there are large differences among species in its extent compared with female care. However, social and ecological factors responsible for interspecific differences in male's share of parental duties remain unclear. Genetic fidelity of females has been long considered important. Theory predicts that females should receive more help from their mates in raising the offspring in species with high genetic fidelity. Using avian incubation behaviour as a model system, we confirmed this prediction. The extent of male's help during incubation increased with decreasing rate of extra-pair paternity across species (22 species of socially monogamous songbirds from 13 families; male's share of incubation ranged from 6% to 58%), even after accounting for covariates, biases in species selection and intraspecific variability. Moreover, this result was not sensitive to two different phylogenies and branch length estimates. We suggest that our findings support the notion, backed by theory, that genetic fidelity is an important factor in the evolution of male parental care. We offer several behavioural scenarios for the coevolution between male's share of parental duties and the genetic mating system.

Why care? Inferring the evolution of complex social behaviour.

Phylogenetic comparative analyses of complex traits often reduce the traits of interests into a single (or a few) component variables. Here, we show that this may be an over-simplification, because components of a complex trait may evolve independently from each other. Using eight components of parental care in 400 bird species from 89 avian families that represent the relative contribution of male vs. female to a particular type of care, we show that some components evolve in a highly correlated manner, whereas others exhibit low (or no) phylogenetic correlation. Correlations were stronger within types of parental activity (brooding, feeding, guarding) than within stages of the breeding cycle (incubation, prefledging care, post-fledging care). A phylogenetically corrected cluster analysis identified two groups of parental care components that evolved in a correlated fashion: one group included incubation and brooding, whereas the other group comprised of the remaining components. The two groups of components provide working hypotheses for follow-up studies to test the underlying genetic, developmental and ecological co-evolutionary mechanism between male and female care. Furthermore, the components within each group are expected to respond consistently to different ambient and social environments.

Randomized comparison of self-fixating and sutured mesh in open inguinal hernia repair.

BACKGROUND: Chronic groin pain after mesh repair of inguinal hernia has been attributed to the presence of sutures. METHODS: This randomized clinical trial compared inguinal hernia repair using a self-fixating composite mesh or a sutured lightweight mesh, with pain at 1 year as primary outcome. Patients completed a self-evaluation questionnaire at 2 weeks and were examined after 1 year. RESULTS: Some 198 patients received self-fixating mesh and 196 sutured mesh. There were no differences between the groups in mean pain scores measured on a visual analogue scale during 2 weeks of immediate convalescence or at 1 year. Chronic pain and discomfort was experienced by 36.3 per cent of patients in the self-fixating and 34.1 per cent in the sutured mesh group (P = 0.658), affecting the everyday life of 1.1 and 2.8 per cent respectively (P = 0.448). CONCLUSION: Open inguinal hernia repair with a composite self-fixating mesh resulted in similar pain in the early postoperative convalescence period and at 1 year as repair with a sutured lightweight mesh.

Fewer and older patients with rheumatoid arthritis need total knee replacement.

OBJECTIVES: Recent studies have suggested a decreased need for orthopaedic surgery in patients with rheumatoid arthritis (RA). We analysed trends in total knee replacement (TKR) in RA using TKR in osteoarthritis (OA) as a point of reference. METHODS: Data on TKRs from the Finnish Arthroplasty Register and population data from Statistics Finland were used to analyse the trends in TKRs among patients aged ≥ 40 years with primary osteoarthritis (OA) or RA in Finland for the period from 1980 to 2010. RESULTS: During 1980-2010, the overall incidence of TKRs increased 20-fold from 14.2 to 305.3 operations per 10(5) person-years. After peaking in 1992, the annual incidence of TKRs for RA decreased gradually from 19.6 to 10.8 per 10(5) [incidence rate ratio (IRR) 0.97, p < 0.001]. The decrease was more pronounced in women and the older (≥ 60 years) age group. The mean age at the time of TKR among patients with RA increased over time, converging with that of patients with OA. CONCLUSION: There is a clear decrease in the annual incidence of TKRs in RA, while among OA patients the incidence is increasing steadily. Furthermore, patients with RA seem to receive their TKRs at an older age. Both of these findings suggest improving long-term outcome in RA.

Domestic chickens defy Rensch's rule: sexual size dimorphism in chicken breeds.

Sexual size dimorphism (SSD), i.e. the difference in sizes of males and females, is a key evolutionary feature that is related to ecology, behaviour and life histories of organisms. Although the basic patterns of SSD are well documented for several major taxa, the processes generating SSD are poorly understood. Domesticated animals offer excellent opportunities for testing predictions of functional explanations of SSD theory because domestic stocks were often selected by humans for particular desirable traits. Here, we analyse SSD in 139 breeds of domestic chickens Gallus gallus domesticus and compare them to their wild relatives (pheasants, partridges and grouse; Phasianidae, 53 species). SSD was male-biased in all chicken breeds, because males were 21.5 ± 0.55% (mean ± SE) heavier than females. The extent of SSD did not differ among breed categories (cock fighting, ornamental and breeds selected for egg and meat production). SSD of chicken breeds was not different from wild pheasants and allies (23.5 ± 3.43%), although the wild ancestor of chickens, the red jungle fowl G. gallus, had more extreme SSD (male 68.8% heavier) than any domesticated breed. Male mass and female mass exhibited positive allometry among pheasants and allies, consistently with the Rensch's rule reported from various taxa. However, body mass scaled isometrically across chicken breeds. The latter results suggest that sex-specific selection on males vs. females is necessary to generate positive allometry, i.e. the Rensch's rule, in wild populations.

Mid-term results for three contemporary total knee replacement designs - a comparative study of 104 patients with primary osteoarthritis.

AIMS: The purpose of this study was to compare retrospectively the mid-term clinical and radiological results of three contemporary knee designs in cohorts operated on in the same hospital during the same time period. MATERIALS AND METHODS: We evaluated mid-term clinical and radiographic outcome of three contemporary total knee designs (the AGC V2, the Duracon and the Nexgen) in 104 consecutive patients (129 knees) operate on for primary knee osteoarthritis at our hospital. The mean indexed age at the time of the operation was 69.2 years (range, 49.3 to 81.1 years). The mean follow-up time was 6.0 years (range, 0.2 to 7.9). All patients were followed for at least three years or until the first revision. In the survival analyses, the end point was defined as, revision for any reason. RESULTS: The Kaplan-Meier survival analysis showed a 98% (95% CI 94-100) survival rate for the NexGen, a 98% (95% CI 93-100) for the AGC and a 90% (95% CI 81-99) for the Duracon design at six years. Both the mean KSS for pain, KSS for function and the mean clinical knee score improved significantly in all three groups. There was no difference between the three designs in mid-term survivorship. CONCLUSIONS: Most of the revisions could be directly linked to perioperative surgical errors. In conclusion, the most recently introduced knee replacements of the present study (Duracon and Nexgen) did not show any clinically significant benefit over the older design (AGC) in the mid-term.

Comparison of standard anteroposterior knee and hip-to-ankle radiographs in determining the lower limb and implant alignment after total knee arthroplasty.

BACKGROUND AND AIMS: The coronal alignment of the lower limb is important for planning and assessing outcome after total knee arthroplasty. This study compared postoperative estimation of alignment and measurement of angles using both hip-to-ankle radiographs and anteroposterior (AP) knee radiographs in standing position. PATIENTS AND METHODS: Consecutive standard AP knee and hip-to-ankle radiographs in 83 patients (103 knees) after total knee arthroplasty were analyzed. RESULTS: The tibiofemoral angle measured from both hip-to-ankle and knee radiographs correlated moderately with the mechanical axis (r = 0.646 and r = 0.540, respectively). The correlation between tibiofemoral angles in the two radiographs was excellent (r = 0.860). Furthermore, measurements of tibial and femoral component alignment between the two radiographs correlated highly (r = 0.718 and r = 0.773, respectively). Intra- and interobserver correlations were high in all analyses. CONCLUSIONS: The standard AP knee radiograph appears to be a valid alternative to the hip-to-ankle radiograph for determining knee coronal plane alignment in routine followup after total knee arthroplasty. However, the hip-to-ankle radiograph alone provides accurate information on weight-bearing mechanical axis in patients with suspected lower limb malalignment.

The function of the hand after operations for obstetric injuries to the brachial plexus.

Hand function was evaluated in 105 patients who had been operated on in early infancy for brachial plexus birth palsy. The mean follow-up after surgery was for 13.4 years (5.0 to 31.5). Fine sensation, stereognosis, grip and pinch strength and the Raimondi scale were recorded. Fine sensation was normal in 34 of 49 patients (69%) with C5-6 injury, 15 of 31 (48%) with C5-7 and in 8 of 25 (32%) with total injury. Loss of protective sensation or absent sensation was noted in some palmar areas of the hand in 12 of 105 patients (11%). Normal stereognosis was recorded in 88 of the 105 patients (84%), whereas only 9 of the 105 (9%) had normal grip strength. The mean Raimondi scale scores were 4.57 (3 to 5) (C5-6), 4.26 (1 to 5) (C5-7) and 2.16 (0 to 5) in patients with total injury. The location of impaired sensation was related to the distribution of the root injury. Avulsion type of injury correlated with poor recovery of hand function.

Shoulder Capsular Surgery in Finland Between 1999 and 2008: A Nationwide Register Analysis.

BACKGROUND AND AIMS: Shoulder capsular surgery is nowadays usually performed arthroscopically, and the proportion of arthroscopic method has rapidly increased during the last two decades. We assessed the incidence of shoulder capsular surgery procedures in Finland between 1999 and 2008. MATERIAL AND METHODS: We gathered the shoulder capsular surgery procedures for all kinds of shoulder instability in Finland between 1999 and 2008 from National Hospital Discharge Register and limited the patient material to include only certain diagnosis (International Classification of Diseases, 10th Edition) and Nordic Medico-Statistical Committee procedure code combinations. We analyzed the data in the whole country, between different age groups, and in university hospital districts. RESULTS: The total incidence of shoulder capsular surgery procedures in Finland increased from 17 to 33 per 100,000 person-years. The incidence of arthroscopic procedures increased from 11 to 30 per 100,000 person-years and the proportion of arthroscopic procedures increased from 63% to 92% between years 1999 and 2007. The incidence of shoulder capsular surgery procedures increased on average around 90% in almost all age groups and particularly in the older age groups. We observed no significant geographical variation between university hospital districts. CONCLUSION: The incidence of shoulder capsular surgery procedures increased on average round 90% in almost all age groups. It seems to be difficult to support the rapidly increased rates of shoulder capsular surgery procedures or the arthroscopic method based on scientific evidence. While also older patients are treated with shoulder capsular surgery, well-defined indications for surgical intervention are needed so that the operations are conducted for the symptomatic patients benefitting most regardless of patients' age.

Intraoperative Complications and Mid-Term Follow-Up of Large-Diameter Head Metal-on-Metal Total Hip Arthroplasty and Hip Resurfacing Arthroplasty.

BACKGROUND AND AIMS: Large-diameter head total hip arthroplasty and hip resurfacing arthroplasty were popular in Finland from 2000 to 2012 for the treatment of hip osteoarthritis. The aim of this retrospective study was to investigate the mid-term survival of large-diameter head total hip arthroplasty patients operated on in three university hospitals and to compare these results to the survival of hip resurfacing arthroplasty patients. MATERIAL AND METHODS: A total of 3860 hip arthroplasties (3029 large-diameter head total hip arthroplasties in 2734 patients and 831 hip resurfacing arthroplasties in 757 patients) were operated on between January 2004 and December 2009. The mean follow-up was 4.3 years (range: 0.3-8.0 years) in the total hip arthroplasty group and 5.1 years (range: 1.7-7.9 years) in the hip resurfacing arthroplasty group. Cox multiple regression model and Kaplan-Meier survival analysis were used to study the survival of the total hip arthroplasties and the hip resurfacing arthroplasties. Intraoperative complications and reasons for revisions were also evaluated. RESULTS: In Cox regression analysis, the hazard ratio for revision of hip resurfacing arthroplasty was 1.5 compared with large-diameter head total hip arthroplasty (95% confidence interval: 1.0-2.2) ( p = 0.029). The cumulative Kaplan-Meier survival rate was 90.7% at 7.7 years for the large-diameter head total hip arthroplasty (95% confidence interval: 86.8-94.6) and 92.2% at 7.6 years for hip resurfacing arthroplasty (95% confidence interval: 89.9-94.6). There were a total of 166/3029 (5.5%) intraoperative complications in the large-diameter head total hip arthroplasty group and 20/831 (2.4%) in the hip resurfacing arthroplasty group ( p = 0.001). Revision for any reason was performed on 137/3029 (4.5%) of the arthroplasties in the large-diameter head total hip arthroplasty group and 52/831 (6.3%) in the hip resurfacing arthroplasty group ( p = 0.04). CONCLUSION: The mid-term survival of both of these devices was poor, and revisions due to adverse reactions to metal debris will most likely rise at longer follow-up. There were more intraoperative complications in the large-diameter head total hip arthroplasty group than in the hip resurfacing arthroplasty group.

Histochemical examination of energy metabolism in aortic vein grafts in rats.

The duration of the presumed metabolic depression of syngeneic vena cava to aorta transplants was determined in rats and the site and type of energy metabolism in the vein grafts assessed. The aerobic metabolic activity was measured from the histochemical reactivity of the enzymes, succinate dehydrogenase and cytochrome oxidase, and the anaerobic activity by staining with lactate dehydrogenase. The activity of the hexose-monophosphate shunt was assessed by the histochemical demonstration of glucose-6-phosphate dehydrogenase. Sixteen hours after grafting a pronounced metabolic depression was noted. Recovery occurred 24 hours after transplantation. The most intense staining was from lactate dehydrogenase in the vein grafts and in the non-transplanted veins. At the end of the observation period of four months the grafts were definitely more strongly stained than the non-transplanted veins, with most of the activity in the thickened intima. This layer had a metabolic profile resembling that of the media of the adjacent aorta.

Scoliosis in patients with diastrophic dysplasia: a new classification.

STUDY DESIGN: Scoliosis in patients with diastrophic dysplasia was analyzed. OBJECTIVES: To study the natural history of scoliosis and to classify the patients with different types of scoliosis. SUMMARY OF BACKGROUND DATA: Typical findings in diastrophic dysplasia are short-limbed short stature, multiple joint contractures, early degeneration of joints, and spinal deformities. The largest studies have reported scoliosis in 37% to 88% of the patients with this rare skeletal dysplasia. The natural history of the deformity is unknown. METHODS: Of the 130 unselected patients, 98 (75%) who were older than 16 years and/or had undergone surgery at the time of the last radiograph were included in the final analysis. These 98 patients included 37 males and 61 females. Their ages at the first radiograph ranged from newborn to 78 years (average, 21 years). The mean follow-up period was 20 years (range, 2-41 years) for 80 patients. Standard standing anteroposterior and lateral radiographs were taken. The degrees of scoliosis, kyphosis, and lordosis were measured according to the Cobb method. Classification of the scoliosis was based on the patient's age at onset of scoliosis, the rate of progression, the magnitude of the scoliosis at the end of growth, and the curve pattern. RESULTS: Of the 98 patients in this study, 86 (88%) had scoliosis. This difference was highly significant statistically (P < 0.001), as compared with the normal population. The frequency of scoliosis was 90% among females and 84% among males. Scoliosis can be divided further into three subtypes: early progressive (11 patients), idiopathic-like (41 patients), and mild nonprogressive (33 patients). One patient had a congenital scoliosis. CONCLUSIONS: Scoliosis is very common in patients with diastrophic dysplasia. The natural history of scoliosis varies from severe deformity with rapid progression to mild deformity without any progression. The authors suggest that the classification described in this report offers a tool for the predicting natural history of scoliosis in diastrophic dysplasia, and for adjusting the timing of surgery in individual patients.

Thoracic and lumbar spine in diastrophic dysplasia: a clinical and magnetic resonance imaging analysis.

STUDY DESIGN: Cross-sectional study to evaluate the thoracic and lumbar spine in patients with diastrophic dysplasia (DD). OBJECTIVES: To find the causative factors behind the spinal deformities and restricted mobility of the spine. SUMMARY OF BACKGROUND DATA: Typical findings in this skeletal dysplasia are short-limbed stature, multiple joint contractures, early degeneration of joints, and spinal deformities such as cervical kyphosis, scoliosis, and exaggerated lumbar lordosis. The pathogenic mechanism of scoliosis is unknown. METHODS: A physical examination was performed on 88 patients (55 females, 33 males) with an average age of 31 years (range, 3-56). Magnetic resonance (MR) images from T2 to S1 and radiographs were obtained. Degree of scoliosis was measured according to Cobb from standing radiographs. The anatomy of the medulla and the size of the spinal canal were assessed. The transverse dural tube area was measured from L2 to S1. Disc space, degeneration, and protrusions were evaluated. Vertebral abnormalities, if any, facet joint degeneration and the state of the spinal muscles were also assessed. RESULTS: Physical examination showed diminished mobility of the spine. Scoliosis was noted in 70 patients with an average of 42 degrees (range, 11-188 degrees ). The mean transverse area of the dural tube ranged from 94 mm(2) at L2-L3 to 57 mm(2) at L5-S1. The area was smaller at all levels compared with reference values (P < 0.001). One patient had severe thoracic and lumbar spinal stenosis. Five patients had compression of neural structures in the lumbar spinal canal in MR images, but had no clinical symptoms. All patients exhibited narrowed disc heights and a decrease in the signal intensity of discs on T2-weighted images. The prevalence of disc protrusions was low; three patients had a prolapse in the lumbar spine. Two patients displayed vertebral anomalies. All patients also had muscular atrophy and degenerative-like facet joint hypertrophy. The severity of these changes increased with age. CONCLUSIONS: Abnormal disc structure and rapid degeneration explain the diminished decreased mobility of the spine and may be a causative factor in the development of scoliosis. Muscular atrophy may be caused by reduced physical activity and rigid spinal deformities. The spinal canal is narrowed, but symptomatic lumbar spinal stenosis is uncommon.

Cervical kyphosis in diastrophic dysplasia.

STUDY DESIGN: An evaluation of cervical kyphosis in diastrophic dysplasia from newborn to adult life. OBJECTIVES: To discover the prevalence and natural history of cervical kyphosis in diastrophic dysplasia. SUMMARY OF BACKGROUND DATA: Typical findings in this rare skeletal dysplasia are sport-limbed short stature, multiple joint contractures, early degeneration of joints, and spinal deformities such as cervical kyphosis, scoliosis, and exaggerated lumbar lordosis. In diastrophic dysplasia, spontaneous resolution of cervical kyphosis has been reported, but so have severe forms causing medullar compression leading to quadriplegia and death. The prevalence and clinical outcome of the kyphosis are not known. METHODS: The radiographic natural history of the cervical spine was studied in 120 patients. They varied in age from newborns to 63-year-olds. The average follow-up time in 26 living patients with cervical kyphosis was 10.0 years. RESULTS: Midcervical kyphosis was noted in 29 patients (24%) in their first radiograph. In 25 patients, the first radiographs were taken before the age of 18 months, and 24 of these patients (96%) had cervical kyphosis. The most severe case was that of a 32-year-old patient with a 165 degrees kyphosis. In the 24 patients, the kyphosis resolved spontaneously at an average age of 7.1 years. Three patients with a severe kyphosis died; one patient is alive. One patient, a 4-year-old child has mild resolving deformity. CONCLUSIONS: Cervical kyphosis in diastrophic dysplasia usually is shown at the time of birth. It resolves spontaneously during growth and seldom needs treatment. Careful follow-up study and treatment, if necessary, are important tools for avoiding the neurologic problems and fatal outcome.

Assessment of metabolic activity in aortic vein grafts in rats by histochemical examination of hydrolases.

The metabolic pattern of aortic vein grafts in rats was studied by estimating histochemically the activity of the hydrolytic enzymes alfa-esterase, aminopeptidase, adenosine triphosphatase, acid phosphatase and alkaline phosphatase. The enzyme activity was lowest in the 16 hour and 1 day old grafts, and recovery was noted at three days. Five days after transplantation the enzyme activities were higher than in the non-transplanted veins. The rapid increase in enzymatic activity found in histochemical studies on wound healing was not seen in these vein grafts. At four weeks some grafts showed intimal thickening the activity of which did not exceed that of the other layers of the graft wall. At the end of the observation period of sixteen weeks most of the grafts showed intimal thickening, and this layer stained intensely especially for ATPase. The staining pattern of most of the grafts at sixteen weeks resembled that of the aortic media.

Enzyme histochemical studies on microarterial grafts in rats.

In order to evaluate the duration and localization of the metabolic changes elicited by the procedure of transplantation, the sequential changes in enzymatic activity of carotid artery grafts in rats were evaluated by histochemical demonstration of the activity of two oxidoreductases, lactate dehydrogenase (LD) and succinate dehydrogenase (SD), and two hydrolytic enzymes, adenosine triphosphatase (ATPase) and alkaline phosphatase (AFOS). The most intense staining for ATPase, LD and SD was seen in the media, both in the grafts and in the adjacent carotid artery. The activity of AFOS was concentrated to the inner parts of the adventitia. The medial layer of the microarterial graft showed no obvious changes in enzyme activity during the observation period of four weeks. At the anastomoses, LD and SD showed decreased activity from day one onwards. No intimal thickening or other clear structural changes were seen in the grafts.

Hip resurfacing arthroplasty versus large-diameter head metal-on-metal total hip arthroplasty: comparison of three designs from the Finnish Arthroplasty Register.

BACKGROUND AND AIMS: Large headed metal-on-metal total hip arthroplasty may produce more metal ions than hip resurfacing arthroplasty. Increased metal-ion levels may be associated with higher revision rates due to adverse reaction to metal debris. The purpose of our study was to compare the survivorship of three hip resurfacing arthroplasty designs with their analogous cementless large-diameter head metal-on-metal total hip arthroplasties. MATERIAL AND METHODS: Based on data obtained from the Finnish Arthroplasty Register, the revision risks of three metal-on-metal hip resurfacing arthroplasty/total hip arthroplasty design couples performed during 2001-2011 were analyzed using the Cox regression model. RESULTS: In the Cox regression analysis for compared design pairs adjusted for age, gender, operated side, head size, diagnosis, and implant, there was no statistically significant difference in revision risk between ReCap hip resurfacing arthroplasty and Bimetric/ReCap total hip arthroplasty (risk ratio = 1.43, confidence interval = 0.95-2.14, p = 0.09) or between Birmingham hip resurfacing arthroplasty and Synergy/Birmingham hip resurfacing total hip arthroplasty (risk ratio = 1.35, confidence interval = 0.75-2.43, p = 0.31). However, the revision risk of Corail and Summit/articular surface replacement total hip arthroplasty (ASR HRA) was significantly increased compared to ASR HRA. (risk ratio = 0.73, confidence interval = 0.54-0.98, p = 0.04). CONCLUSION: We conclude that the short-term revision risk of large headed metal-on-metal total hip arthroplasties was not increased compared to analogous hip resurfacing arthroplasties in two out of three devices studied at a nationwide level. There may be implant-related factors having an effect on the success of single manufacturer devices. However, more information on the incidence of adverse soft-tissue reactions in these patient cohorts is needed.

Upper cervical spine fusion in children with skeletal dysplasia.

BACKGROUND: Skeletal dysplasias have been associated with upper cervical instability. Many patients are initially asymptomatic, but the instability may progress to subluxation and dislocation and complications thereof, including death. Surgery is hampered by petite osseous structures and low bone formation rate. AIM: To review the outcomes of surgical fusion of upper cervical instability in children with rare skeletal dysplasias. MATERIAL AND METHODS: A retrospective study of eight children with five different rare skeletal dysplasias needing upper cervical instrumented stabilization. Cases were evaluated for clinical, radiologic, and quality-of-life outcomes, with median follow-up time of 5 years. RESULTS: Six patients underwent posterior, segmental cervical spine instrumentation and fusion (three C1/C2 fusions, three occipitocervical fusions), one anterior cervical instrumented spinal fusion, and one anteroposterior fusion. Autogenous bone grafting was used in all patients, and seven were immobilized using a halo body jacket. Nonunion in occipitocervical fusions was common in these patients (3/8 patients). Rib autograft from occiput to cervical spine with recombinant human BMP-2 was used to salvage nonunions. CONCLUSIONS: Surgical fixation in the pediatric cervical spine is hampered by fragile posterior structures. A postoperative immobilization by halo vest for 4 months is customary. Selective anterior corpectomy and plate fixation is not recommended in pediatric patients with skeletal dysplasias. LEVEL OF EVIDENCE: Level 4, Case Series.

Cementless total hip arthroplasty with large diameter metal-on-metal heads: short-term survivorship of 8059 hips from the Finnish Arthroplasty Register.

BACKGROUND AND AIMS: Population-based register data from the National Joint Register of Australia and England and Wales have revealed that the mid-term outcome of cementless large diameter head metal-on-metal total hip arthroplasty is inferior to that of conventional cemented metal-on-polyethylene total hip arthroplasty. The aim of this study was to compare the results of cementless large diameter head metal-on-metal total hip arthroplasty with conventional cemented arthroplasty in Finland. The second aim of this study was to compare the cementless large diameter head metal-on-metal models with each other. MATERIAL AND METHODS: Based on the data extracted from the Finnish Arthroplasty Register, the risk of revision of 8059 cementless large diameter head metal-on-metal total hip arthroplasties performed during 2002-2009 was analyzed using Cox regression model. The revision risk of these hips was compared to that of 16,978 cemented metal-on-polyethylene total hip arthroplasties performed during the same time period. RESULTS: In the Cox regression analysis, there was no difference in revision risks between cementless large diameter head metal-on-metal total hip arthroplasty and cemented metal-on-polyethylene total hip arthroplasty (relative risk = 0.90, confidence interval = 0.74-1.10, p = 0.3). However, in female patients aged 55 years or above, cementless large diameter head metal-on-metal total hip replacements showed a significantly increased risk of revision as compared to cemented total hip replacements (relative risk = 1.33, confidence interval = 1.04-1.70). Compared to the reference implant in this study (cementless Synergy stem combined with Birmingham Hip Resurfacing [BHR] cup), the CementLess Spotorno (CLS) stem combined with Durom cup had a 2.9-fold (95% confidence interval = 1.17-6.90) increased risk of revision. CONCLUSIONS: We found that cementless large diameter head metal-on-metal total hip arthroplasty had short-term survivorship compared with cemented total hip arthroplasty at a nation-wide level. However, in female patients aged 55 years or above, cementless large diameter head metal-on-metal total hip arthroplasty showed inferior results. Furthermore, implant design had an influence on revision rates. Longer follow-up time is needed to assess the success of large diameter head metal-on-metal total hip arthroplasty.