Aims. In this study, we aimed to evaluate incidence trends and potential risk factors associated with Perthes’ disease in Denmark, using publicly available data. Methods. Our population-based case-control study used data from the Danish National Patient Register and Danish Civil Registration System, accessed through the publicly available Danish Biobank Register, to identify 1,924,292 infants born between 1985 and 2016. We estimated age-specific incidence rates for four birth periods of equal duration (1985 to 1992, 1993 to 2000, 2001 to 2008, and 2009 to 2016) and investigated associations with perinatal conditions, congenital malformations, coagulation defects, autism spectrum disorders (ASD), and attention deficit hyperactivity disorders (ADHD). Results. We identified 2,374 (81.6% male) diagnosed with Perthes’ disease aged between two and 12 years, corresponding to an overall incidence of 12.1 per 100,000 live births relative to the year of birth. The incidence declined across all four birth periods, irrespective of sex or age at diagnosis. Several perinatal conditions were associated with higher Perthes’ disease risk. Children with reported birth injuries (vs no reported injuries) exhibited the highest risk (relative risk (RR) 7.48 (95% CI 3.37 to 16.63)) followed by those with versus without coagulation defects (RR 4.77 (95% CI 1.79 to 12.69)). Children diagnosed with syndromic (RR 2.90 (95% CI 2.08 to 4.04)) or non-syndromic major congenital malformations (RR 1.86 (95% CI 1.55 to 2.23)) (vs those with no malformation diagnosis) were also associated with higher Perthes’ disease risk. The development of Perthes’ disease was positively associated with several ASD and ADHD diagnoses. However, once adjusting for the sex of the child and period of birth, the associations with ASD and ADHD were no longer significant. Conclusion. Using publicly available data, we observed a declining incidence of Perthes’ disease in Denmark over a 32-year study period. Our findings also confirm positive associations between Perthes’ disease and various perinatal conditions, coagulation defects, and congenital malformations, highlighting potential aetiological pathways for further investigation. Cite this article: Bone Joint J 2025;107-B(2):268–276

Introduction. Amputation or disarticulation is a reliable option for management of severe foot deformities and limb-length discrepancies, the surgical restoration of which are unpredictable or unfavourable. Of the various surgeries involving foot ablation, Syme's amputation is preferred for congenital deformities as it provides a growing, weight bearing stump with proprioception and cushioning. Materials and Methods. We reviewed data of all children who underwent Syme's amputation over the past 13 years at our institution. Surgical technique followed the same principles for Syme's but varied with surgeons. Results. Ten boys and ten girls, with an average age of 18 months and average follow up of 70 months were included in the study. The most common indication was fibular hemimelia. Wound complications were reported in three children, phantom pain in one, heel pad migration in two. None had wound dehiscence, flap necrosis, stump overgrowth, or calcaneal regrowth. None of this required surgical intervention. One child required an amputation at a higher-level secondary to a congenital malformation of nervous tissue in the affected leg. Prosthetic compatibility was 94.7 % and none used mobility aids. Six children participated in sports. Conclusions. Syme amputation is a safe and potentially advantageous procedure in children, with a low incidence of complications to offer patients with non-salvageable foot conditions. It offers good prosthetic use with minimal risk of complications and can offer patients a functional solution with only one surgical intervention throughout their childhood

Cerebral Palsy (CP) is a group of disorders that affect movement and posture caused by injury to the developing brain. While prematurity and low birth weight are common causes in developed countries, birth asphyxia, kernicterus, and infections have been identified as predominant aetiologies in Africa. There is, however, very little information on the aetiology of CP in South Africa. The purpose of this study was to determine the aetiology, severity, and topographical distribution of CP in children undergoing orthopaedic surgery at our tertiary paediatric unit. A retrospective folder review was performed for patients with CP that underwent orthopaedic surgery from July 2018 to June 2022. Data was collected on perinatal circumstances, aetiology or risk factors for developing CP, severity of disability as classified by the Gross Motor Function Classification Scale (GMFCS) and topographical distribution. Descriptive analysis was performed. Two-hundred-and-thirty-four patients were included in the analysis. No specific aetiology could be identified in 51 (21.9%) patients. Hypoxic ischaemic encephalopathy (HIE) accounted for 23.6% of patients and was the most common aetiology across the different categories except for patients graded as GMFCS 2, in whom prematurity was the most common aetiology. Congenital brain malformations (10.5%) and cerebral infections, including HIV encephalopathy (11.4%) were the next most frequent aetiologies, followed by prematurity (7.6%), ischaemic stroke (6.8%) and intraventricular haemorrhage (6.3%). Fifty-two percent of patients were classified as GMFCS 4 or 5. There was a predominance of quadriplegic patients (37%) compared to hemiplegics (29%), diplegics (30%) and monoplegics (4%). Most patients undergoing orthopaedic surgery for musculoskeletal sequelae of CP were severely disabled quadriplegic patients in whom HIE was the predominant cause of CP. This emphasises the need for intervention at a primary care level to decrease the incidence of this frequently preventable condition

Malignant hyperthermia (MH) is a pharmacogenetic disorder, potentially lethal, due to the exposure to anesthetic drugs that triggers, a high increase of corporal temperature, progressive muscular stiffness, severe rabdomiolisis and death due to cardiac dysfunction. Many research works relate Malignant Hyperthermia to muscular illnesses or to the King Syndrome. Through this study we present the incidence of MH in patients with congenital vertebrae malformations. (CVM). The objective is to establish the incidence of the MH in patients who were operated on CVM and to alert about this association. 1029 patients with CVM were treated between 1972 and 2000. 390 with congenital vertebrae malformation were operated on. 3 patients (0.76%) (1 girl and 2 boys) developed MH while they underwent surgical treatment for the CVM. 1 patient presented an isolated congenital vertebrae malformation. 1 patient presented King Syndrome and the other presented Robert Syndrome. Only 1 elevated amount of preoperative CPK was found (the are no reports on the others). No muscular biopsy was done to test sensitivity. Two of them were biopsied for a post episode study. At the surgical moment, any patients reported personal or familiar antecedents of MH. No deaths were reported, although it is considered as a potentially lethal disorder. We found no reports in the literature in this subject. Most of the bibliographic data belonged to anesthesiologists or geneticists. Our approach as spine surgeons leaded us to the detailed analysis of this studies and the 0.76% (3 out of 390) incidence suggested us to have an alert attitude when facing patients with surgical MVC and take the necessary precautions

Introduction. Metal-on-Metal (MoM) bearing surfaces were historically used for young patients undergoing total hip arthroplasty, and remain commonplace in modern hip resurfacing. In theory, it has been postulated that metal ions released from such implants may cross the placental barrier and cause harm to the fetus. In light of this potential risk, recommendations against the use of MoM components in women of child-bearing age have been advocated. The purpose of this systematic review was to evaluate: 1) the Metal-on-Metal bearing types and ion levels found; 2) the concentrations of metals in maternal circulation and the umbilical cord; and 3) the presence of abnormalities in the fetus. Methods. A comprehensive literature review was conducted of studies published between January 1st, 1975 and April 1st, 2019 using specific keywords. (See Fig 1). We defined the inclusion criteria for qualifying studies for this review as follows: 1) studies that reported on the women who experienced pregnancy and who had a Metal-on-Metal hip implant; 2) studies that reported on maternal metal ions blood and umbilical cord levels; and 3) studies that reported on the occurrence of fetal complications. Data on cobalt and chromium ion levels in the maternal blood and umbilical cord blood, as well as the presence of adverse effects in the infant were collected. Age at parturition and time from MoM implant to parturition were also collected. A total of 6 studies were included in the final analysis that reported on a total of 21 females and 21 infants born. The mean age at parturition was 40 years (range, 24–41 years), and the mean time from MoM implantation to parturition was 47.2 months (range, 11–119 months). Results. Maternal blood cobalt levels were found as a weighted average of 33.94ug/L (0.972–143), while umbilical cord blood cobalt levels were found to be 22.07 ug/L(0.486–75). Cobalt levels were reduced by an average of 35% between maternal and umbilical cord blood. Maternal cord blood chromium levels were found as a weighted average of 9.25 ug/L (1–25), while umbilical cord chromium levels were found to be 1.30 ug/L(0.288–2.3). Chromium levels were reduced by an average of 86% between maternal and umbilical cord blood. No cobalt or chromium was detected in the umbilical cord blood of three patients. Out of the 21 infants born to women with MoM implants, 20 were born healthy with no adverse effects or complications. Conclusion. To date, there is a lack of consensus as to whether Metal-on-Metal hip arthroplasty implants are to be avoided in the child-bearing female population and whether it constitute a hazard to the fetus in-utero. Both chromium and cobalt ions were markedly reduced in levels when transitioning from maternal to cord blood. In particular, chromium showed a greater reduction on average than cobalt (86% vs. 35%). Based on the current evidence, there appears to be no correlation between the presence of metal ions in umbilical cord blood and complications, particularly congenital malformations in the fetus, as none of the infants experienced abnormalities uniquely attributable to the presence of metal ions. For any figures or tables, please contact the authors directly

Congenital Hand Deformities are probably the most frequent cause of non-traumatic complaint in consultations on paediatric hand surgery. The incidence of occurrence is about 1 in 500 live births. Some of these abnormalities are minor and do not interfere with function. Many, however, have a significant functional and/or cosmetic deformity. Only a few congenital malformations have a regular single gene mode of transmission, most have an irregular and unpredictable pattern of inheritance; sometimes occurs as part of a malformation syndrome or skeletal dysplasia, or in a sporadic way. In fact, the cause for 40 to 50% of these anomalies is “unknown”. Themes like handling the patient and parents and the psychological effects of the anomaly, the general principles of treatment, timing of surgery and the principles of reconstructive surgery are discussed. The classification proposed by A.B. Swanson and revised with the assistance of the Congenital Anomalies Committee of the International Federation of Societies fo Surgery of the Hand will be used to propose the general guides of treatment. The most common anomalies will be approached in more detail and the option of treatment is discussed in base of experience of the author

Introduction: Between 1 and 4 per 1000 births worldwide are affected by clubfoot. Clubfoot etiology is unclear, but both genetic and environmental factors are thought to be involved. Low folate status in pregnant women has been implicated in several congenital malformations and folate metabolism may be affected by polymorphisms in the MTHFR gene. Methods: Using a case-parent triad design, we investigated whether the MTHFR C677T polymorphism, and maternal peri-conceptional folic acid supplement use, influenced risk of isolated clubfoot. 375 case-parent triads took part. Results: Among children there was a significant trend of decreasing clubfoot risk with increasing number of Talleles: relative risk (RR ) CT vs CC=0.75 (95% CI: 0.57,0.97); RR TT vs CC=0.57 (95% CI: 0.37,0.91); p trend=0.006. This association was not modified by maternal folic acid use. Conclusion: Maternal MTHFR genotype did not influence risk of clubfoot in the offspring overall, although a possible interaction with folic acid use was found. This is the first report of a specific genetic polymorphism associated with clubfoot. The direction of the association is intriguing and suggests DNA synthesis may be relevant in clubfoot development. However, clubfoot mechanisms are poorly understood and the folate metabolism pathway is complex. Further research is needed to elucidate these relationships

Introduction and purpose: The purpose of this paper is to assess the results of a revision of upper and lower limb lengthening procedures performed between 1998 and 2002 in our limb-lengthening unit. Materials and methods: Twenty patients were revised, 8 males and 12 females (mean age: 12.5 years; range: 4.5 – 20). 11 of these cases had been caused by leg length discrepancy (6 congenital malformations, 2 sequelae of osteoarthritis, 1 posttraumatic, 1 exostosing disease and 1 sequela of poliomyelitis) and in 9 cases the lengthening was performed in cases of short stature (6 achondro-plasias, 2 Turner syndromes and 1 familial short stature). The global number of lengthenings was 44 (22 tibias, 15 femurs, 6 humeruses and 1 ulna). In all cases the Verona school method was employed. The external monolateral railfixator was used (with 4 or 6 pins). Results: The global healing index was 30.1. The lowest scores were those of the humerus and the highest those of the tibia. The most frequent complication was the superficial infection of the pins (36.3%). The most frequently isolated germ in the exudates was S. epidermidis. There were no cases of deep infection. In all cases of leg length discrepancy the desired goal was achieved. Discussion and conclusions: The healing index obtained in our series is a reliable indicator of the good results achieved by limb lengthening procedures performed in our department

Purpose: Upper cervical spine stabilization in children can be challenging due to anatomic abnormalities such as incomplete posterior elements, vertebral artery variability and small patient size. Several techniques have been described for stabilization of the upper cervical spine, each with its own advantages and disadvantages. Since the introduction of the technique by Harms, many authors have shown C1 lateral mass screws to be safe and effective in the stabilization of the upper cervical spine in adults. No large series of paediatric C1 lateral mass screw fixation has been reported in the literature. The purpose of this study was to describe the indications, technique, and outcomes of C1 lateral mass screw fixation in a consecutive series of 11 paediatric patients. Method: A database generated retrospective review of all patients who underwent C1 lateral mass screw fixation as part of an upper cervical spine stabilization construct was performed. In all patients the C2 dorsal root ganglion was sacrificed. Patient demographics and clinical outcomes were obtained through chart review. Radiographs immediately post-operatively, at six-weeks, three-months, and final follow-up were reviewed. Results: Eleven consecutive paediatric patients underwent bilateral C1 lateral mass screw fixation for a variety of conditions including C1-C2 instability, deformity, congenital malformation, trauma, as well as revision surgery. The average age was 10 years (range 4 to 16 years) with a mean follow-up of 11 months (range 6 – 18 months). There were no iatrogenic vertebral artery, hypoglossal nerve or spinal cord injuries. All 11 patients had solid fusion clinically and radiographically, with no loss of fixation. The C2 dorsal root ganglion was sacrificed in all patients with resulting minor occipital parasthaesia that progressively diminished in severity. Conclusion: This is the largest series of consecutive patients reported in the literature to date showing that the technique is safe and effective, with acceptable morbidity when applied to the paediatric population. We believe that C1 lateral mass screws offer significant advantages over traditional fixation techniques when the C1 vertebra is to be included in an upper cervical instrumented construct

Introduction: Thumb duplication is one of the most common congenital malformations of the hand. The goals of surgery are to ablate the hypoplastic component and to create a stable and well-aligned thumb with a good pinch-function besides a maximum of mobility. Yet this aim is seldom achieved by simple ablative surgery alone which often results in a residual deformity and loss of function. The objective of this review is a critical analysis of the used surgical techniques in 113 cases of thumb duplication. Patients and Methods: Within the 11 year period from 1992 to 2003 113 patients (67 male, 46 female) with 120 duplicated thumbs (7 bilateral) underwent surgery at our institution. Details of primary reconstruction, X-ray findings, follow-up details, analysis of secondary deformities and details of secondary surgery were documented and evaluated. The follow-up time ranged from 6 months to 10 years. The patients were evaluated for functional and cosmetic outcomes. Results: The right thumb was involved in 63 patients, the left in 57 and both sides were affected in 7 cases.11 Patients had associated anomalies. Using the classification proposed by Wassel to grade the thumb duplication the most frequent types were IV with 53 cases (48%), II with 27 cases (24%). Patient age at the time of initial surgery varied from 5 months to 26 years with a mean age of 20 months. 11 patients underwent previous surgery in another institution and had a second surgery at our hospital. 8 Patients underwent only simple ablation, in 88 cases there was an excision combined with reconstruction of collateral ligaments, in 51 cases combined with a tendon transfer or release and reinsertion. Osteotomy of the metacarpal bone or proximal phalanx was performed in 47 cases. 5 patients received a Bilhaut-Cloquet procedure. The most common complications were joint deviation (n = 12), joint stiffness (n = 2), joint instability (n = 11), nail deformity (n = 5) and scarring (n = 7). The 10 patients who under-went primary surgery at another institution and had to be reoperated are included in this listing. The type of secondary reconstruction was in 7 cases scar release, in 6 cases a ligament reconstruction, 4 patients received an arthrodesis and 6 patients needed a corrective osteotomy. Conclusions: Thumb function is critical to hand function. Despite its seeming simplicity surgery of thumb duplication is a complex procedure. Nowadays it is recognized that simple ablation leeds mostly to poor functional and cosmetic results. Treatment requires a thoroughful preoperative assessment, as well as an appreciation and understanding of the bony, capsuloligamentous and tendinous components involved. Taking this into account in mostly all cases a satisfactory cosmetic and functional result can be achieved

Purpose: Parent worry about torsional or angular anomalies of the lower limbs of their children is widespread. The relationship between a child’s postural habits and torsional anomalies of the lower limbs is often mentioned in the literature despite the lack of a single study demonstrating solid evidence. Active treatment of such anomalies is exceptionally necessary. Postural education is undoubtedly provided by parents. The purpose of this study was not to establish a cause and effect relationship between postural habits and torsional anomalies but rather to determine whether children who exhibit a preferential nocturnal and diurnal posture have torsional anomalies of the lower limbs. Material and methods: This retrospective analysis included all patients consulting one paediatric orthopaedist for in-toeing during a period of six years. Patients with a neurological disorder, bone and joint disease, or a congenital malformation as well as those with a history of orthesis use for fracture or surgery of the lower limbs were excluded. The cohort was composed of 463 children aged 1.5 to 15 years. Five habitual postures were studied: sitting cross-legged, sitting on knees feet under the buttocks, laying on knees with buttocks upward and feet inward, laying on belly knees extended and feet inward, and indifferent sitting and reclining positions. Abnormal torsion was determined clinically. Internal hip rotation greater than 70 (Staheli) observed in the ventral decubitus position with knees flexed 90° was considered to indicate excessive femoral anteversion (EFAV). Internal tibial torsion (ITT) was considered to be present when the thigh-foot angle was 0 measured in the ventral decubitus position or sitting on the table legs hanging. We searched for correlations between habitual posture and abnormal torsion as well as the influence of gender and age using the chi-square test and 95% confidence intervals. Patients with both EFAV and ITT were stratified by group using the Woolf method associated with the Mantel-Haenszel test. Results: Abnormal torsion was found more often in children aged less than 4 years with no difference between boys and girls. Among the children in this study presenting in-toeing, 31% did not have a preferred sitting or reclining position and only 7% presented clearly abnormal torsion. There was a significant direct correlation between EFAV and sitting crosslegged and a significant inverse correlation between EFAV and the other habitual postures. Conversely, there was no significant correlation between ITT and the habitual postures studied. Discussion and conclusion: This study provided objective information concerning widely accepted but poorly documented notions. There were two limitations: 1) the lack of a control group not presenting in-toeing, 2) the absence of precise goniometric measurements, a problem encountered in most studies using clinical methods. Although the presence of abnormal torsion of the lower limb appears to significantly influence the gait pattern in children, it does not appear to affect habitual postures. A significant relationship was found only between habitual posture and EFAV, and not ITT. These results should be taken into consideration when planning treatment

Introduction: Although the ultrasound diagnosis of neural tube defects has been described extensively, anomalies of the fetal vertebral bodies have received little attention. This study aims to document the incidence of congenital hemivertebrae, the association with defects of other organ systems and discuss the outcome. Methods: All fetuses with ultrasonographically detected vertebral anomalies presenting to the above institution over a four year period were included in the study. Those with open neural tube defects were excluded. The level and Cobb angle (where possible) were estimated from the 18 week scan. Associated congenital anomalies were noted. Radiographs were taken soon after birth and checked for accuracy of original diagnosis and patients were monitored for curve progression. Results: Fourteen fetuses with congenital hemivertebrae were found from a total of 12,000 routine antenatal scans. Maternal age ranged from 22–32 years (mean 26.8 years) with an average term of 36.3 weeks (range 29–40). Only two fetuses were born prematurely: one at 33 weeks as part of a twin gestation (only one of the twins had an isolated hemivertebrae) and the other at 29 weeks via emergency caesarian section for fetal distress. This pregnancy was complicated by the oligohydramnios sequence (Potter syndrome). Ten of 14 fetuses had an isolated hemivertebrae. Two had VATER association (oesophageal and anal atresia) and two had multiple mosaic type congenital scoliosis, one of which had associated rib and abdominal wall malformation. All pregnancies resulted in live births. All except one child remain well at latest follow-up (average 25 months). The infant born at 29 weeks has had multiple complications of prematurity. Vertebral anomalies appeared in the thoracic spine in five, the lumbar spine in eight and the sacrum in one resulting in scoliosis in 13 and kyphosis in one. The average antenatal Cobb angle was 30°. The average postnatal Cobb angle was 32° (range 18–42). Accuracy of localisation (level and type) was good with only one error due to inability to see the S1 hemivertebrae. Six of the 14 had surgery before the age of 24 months, with the youngest aged three months. In this group the average pre-operative Cobb angle was 35° (range 25–42°). Three patients had anterior and posterior fusion in-situ without instrumentation. Three patients had hemivertebrectomy with correction and posterior instrumentation of the spine. Conclusion: In general sonographically detected isolated fetal hemivertebrae carry a good prognosis. If associated with the oligohydramnios syndrome the fetus is at high risk. Ultrasound appears accurate in the diagnosis of both the level and type of congenital malformation. The value of early surgical management needs continued assessment

Aims

Periacetabular osteotomy (PAO) is well established for acetabular reorientation and has shown successful improvement in patient-reported outcome measures (PROMs). Nevertheless, studies focusing on postoperative outcomes related to patient individual factors are still underrepresented. Therefore, this study aimed to analyze the functional outcome and activity level in relation to patient sex with a minimum follow-up of two years after PAO for mild to severe hip dysplasia.

Purpose: Ligament laxity is a common feature of trisomy 21 and is incriminated in most of the orthopaedic disorders observed. Early diagnosis and management is essential. C1-C2 instability is a recognised manifestation in trisomy 21 and is associated, at least theoretically, with significant risk of cord complications. The purpose of this work was to provide a descriptive analysis of the C1-C2 joint in trisomy 21 and to analyse instability factors in order to determine the tolerable C1-C2 distance. Material and methods: Within the framework of a French national epidemiology survey of trisomy 21, we focused on the C1-C2 joint. A total of 472 children with trisomy 21 were identified; 458 who were examined were included in this study. Careful history taking and a detailed physical examination with neurological tests (search for even minimal signs of neurological disorders) was conducted. The Carter and Wilkinson method was used to assess joint laxity. The same specialist searched for other orthopaedic disorders. Patients were divided into two groups depending on the presence or absence of neurological signs. Two groups were also distinguished according to the presence or absence of generalised laxity (Carter and Wilkinson). Lateral x-rays centred on C1-C2 were performed by the same technician on the same machine with the patient in a neutral position, hyperflexion and hyperextension. The same technique inspired by the method described by Singer et al. and modified for simplification was used in all cases. The same observer interpreted the images using a single-blinded protocol to search for congenital malformations and signs of degeneration, measure the C1-C2 distance the minimal sagittal diameter and the C1-C2 angle (not reported in the literature and described for this study). These measures were then compared with data in the literature as available and correlated by age, gender, presence of neurological signs and joint laxity. Seven patients were excluded from the study due to insufficient cooperation for the x-rays and nine because of incomplete clinical or radiological data. The statistical analysis was performed on data from 442 patients. Quantitative variables were compared with the Pearson test and parameteric ANOVA was used to search for correlations of quantitative and qualitative variables. Significance was set at p< 0.05. Results: Mean patient age was 13.8 years. There were 184 girls and 258 boys. Minor neurological anomalies were found in 42% of the patients. There were no cases of major motor deficit. Generalised laxity as defined by Carter and Wilkinson was observed in 24% of patients. Other orthopaedic problems, basically of the foot, were found in 85%. The radiograms revealed a very wide range of measures were thus expressed as means. The C1-C2 distance was greater than 4 mm in 34 patients on the flexion films (limit established in the literature for instability in trisomy 21). The maximal C1-C2 distance in the neutral position was 8 mm, 9.6 mm in flexion. The lowest minimal sagittal distance was 8 mm in flexion and 10 mm in the neutral position (the lower limit reported in the literature before considering the cord to be threatened in 14 mm). The greatest variability was found for the C1-C2 angle. Ligament laxity and atlantoaxial distance were inversely proportional to patient age, but there was no significant correlation between atlantoaxial instability (C1-C2 distance > 4 mm) and gender or generalised hyperlaxity. There was no significant correlation between C1-C2 instability or laxity and neurological signs. Discussion and conclusion: Compared with earlier publications, our series offers the advantage of a large unselected population providing epidemiological data on trisomy 21. A standard radiography protocol was used. The large majority of the radiographic measures reported in the literature do not take into account the magnification effect nor position variability between patients. Our findings confirm certain data in the literature and also provide new information suggesting it could be useful to revisit certain pathogenic hypotheses about C1-C2 instability and its neurological consequences in trisomy 21. Two important observations were the absence of a correlation between general laxity and C1-C2 instability and the absence of correlation between C1-C2 instability and the presence of neurological signs

Purpose: We reviewed a series of pollicizations in children with congenital thumb malformations. The purpose of this study was to assess the influence of anatomic or technical factors on functional and cosmetic outcome. Material: The series included 33 operations in 26 children. The Blauth classification was: grade IIIA (n=1), grade IIIB (n=8), grade IV (n=8), grade V (n=13), mirror hand (n=8). We noted the type of skin incision, technique used to fix the metacarpal head on the carpus, and tendon shortenings. Results were assessed at mean 4 years follow-up on the basis of the cosmetic aspect (parent satisfaction) and functional outcome measured with the Kapandji index and flexion-extension of inter-phalangeal joint, thumb finger opposition, and sensitivity. Results: Mean age at surgery was 32 months. Fixation was achieved with sutures in 24 cases and pinning in nine. Tendon shortening was performed in 16 cases on the extensor system and in one case on the deep flexor system. Mean follow-up was four years. There was no significant difference between groups A and B for cosmetic outcome. The main factor influencing objective functional outcome was the association of a grade III or IV radial club hand. In these patients, the final outcome was compromised by the stiffness or deformation of the radiocarpal joint and the stiffness of the preoperative Kapandji index which was 7 (mean) in group A and 4.75 in group B. Discussion and conclusion: The following technical aspects did not have a significant effect on the final functional result in our series: type of skin incision, type of carpal fixation, shortening the extensor or flexor system. Technical aspects which must be performed with particular care include reconstruction of the thenar muscles using interosseous muscles, curettage of the growth cartilage of the head of the second metacarpus, and hyper-extension of the head of the second metacarpus during fixation onto the carpus. Careful technique avoids future complications such as excessive growth of the neometa-carpus or Z-thumb