Pierre Moens

Involvement of PLEKHM1 in osteoclastic vesicular transport and osteopetrosis in incisors absent rats and humans

This study illustrates that Plekhm1 is an essential protein for bone resorption, as loss-of-function mutations were found to underlie the osteopetrotic phenotype of the incisors absent rat as well as an intermediate type of human osteopetrosis. Electron and confocal microscopic analysis demonstrated that monocytes from a patient homozygous for the mutation differentiated into osteoclasts normally, but when cultured on dentine discs, the osteoclasts failed to form ruffled borders and showed little evidence of bone resorption. The presence of both RUN and pleckstrin homology domains suggests that Plekhm1 may be linked to small GTPase signaling. We found that Plekhm1 colocalized with Rab7 to late endosomal/lysosomal vesicles in HEK293 and osteoclast-like cells, an effect that was dependent on the prenylation of Rab7. In conclusion, we believe PLEKHM1 to be a novel gene implicated in the development of osteopetrosis, with a putative critical function in vesicular transport in the osteoclast.

Slipped capital femoral epiphysis: a long-term follow-up, with special emphasis on the capacities for remodeling

We reviewed 59 hips in 44 children with slipped capital femoral epiphysis (SCFE), all treated by in situ pinning. The average clinical and radiographic follow-up was 11.4 years. Fifty-three hips (90%) were rated as either excellent or good. Osteonecrosis or chondrolysis developed in five patients. Postoperative remodeling was noted, not only by a process of local resorption and apposition of bone, but also by correction of the disturbed anatomic axes, in proportion to the severity of the slip, together with global thickening of the femoral neck. We believe that the good long-term results after in situ pinning are the consequence of this important remodeling process.

Lateral shelf acetabuloplasty in the early stage of Legg-Calvé-Perthes disease with special emphasis on the remaining growth of the acetabulum: a preliminary report.

This study reports on the preliminary results in 43 patients with an early stage of unilateral Legg–Calvé–Perthes disease, treated with a shelf acetabuloplasty. The mean postoperative follow-up was 3.7 years (1.3–6.2 years). The results suggest an improved outcome in children older than 5 years of age at onset. According to the Stulberg classification, 16 hips were classified as Stulberg 2, 19 hips as Stulberg 3 and eight hips as Stulberg 4. The acetabular size, which is a measurement of the length of the acetabulum relative to the size of the shelf, increased from 48.86 to 69.13%. This reflects an incorporation of the shelf-graft into the pelvis as a result of continued growth of the lateral acetabular structures. The coverage of the femoral head by the bony acetabulum increased from 68.51 to 73.83%. The acetabular cover increases in children younger than 8 years of age and decreases in patients older than 8 years. We suggest that shelf acetabuloplasty can be considered as an appropriate surgical treatment for children older than 5 years of age, with severe Legg–Calvé–Perthes disease.

Split posterior tibial tendon transfer through the interosseus membrane in spastic equinovarus deformity

The split posterior tibial tendon transfer procedure was first reported by Green for correction of equinovarus hindfoot deformity in patients with cerebral palsy. A modification of the split posterior tibial tendon transfer combined with an Achilles tendon lengthening is described in 17 children (21 procedures) with a minimum follow-up of 3 years. This modified technique is indicated in young children with a continuously spastic posterior tibial tendon to correct a dynamic equinovarus. It restores active dorsiflexion when the anterior tibial and extensor muscles are weak. The anterior half of the split tibialis posterior is transferred through the interosseus membrane to the dorsum of the foot. Excellent or good results and two poor results were noted after a mean follow-up of 29 months. In the patients with an excellent or good result, marked improvement of their equinovarus foot deformity in stance and swing phase of gait was seen. In two patients, the procedure failed because of technical errors.

Bilateral Legg-Calvé-Perthes disease: different from unilateral disease?

Twenty-five patients or 50 hips with bilateral Legg-Calvé-Perthes disease were reviewed at skeletal maturity in the orthopaedic departments of Leuven, Belgium, and Montpellier, France. The two groups were very similar as to age at onset of the disease, severity of involvement, and classification at skeletal maturity. The results seem to indicate that bilateral disease runs a more severe course as compared with unilateral Legg-Calvé-Perthes disease. Eighty percent presented with a Catterall group III and IV and Herring classification B and C. Forty-eight percent rated as Stulberg 4 and 5 at skeletal maturity.

A new technique for the three-dimensional study of the spine in vitro and in vivo by using a motion-analysis system

We introduce a new method with a motion-analysis system (MAS) to study the vertebral model in vitro. Compared with the currently most accurate technique, roentgen stereophotogrammetric analysis (RSA), the difference between the RSA and the MAS is 0.12 degree +/- 1.64 degrees. An accuracy with an error of 0.08 degree +/- 1.15 degrees is determined by means of an angle gauge. Although a significant difference between the MAS and the goniometer (p = 0.04) is found around the X-axis (theta; transverse plane), it is limited to < 1 degree. The MAS provides an in-depth insight into the mechanism of the three-dimensional rotation at each vertebra in vivo. The backward inclination of the apical vertebra (AV) and forward inclination of the upper-end vertebra (UEV) around the Y-axis (phi) results in a correction of the hypokyphosis shown by the Cobb angle in the sagittal plane. The clockwise rotation of the UEV in the Z-axis (psi) leads to a reduction of the Cobb angle in the frontal plane. Additionally, the MAS as an intraoperative alternative shows different results of the derotation maneuver by the Cotrel-Dubousset instrumentation (CDI) compared with the computed tomography (CT) scan. Our method gives more direct details of the derotation not influenced by patient posture, as observed in the CT scan.

Three cases of Kingella kingae infection in young children

We describe three cases of Kingella kingae infection in young children hospitalised in our institution, and draw attention to the importance of proper handling of synovial fluid. In March 1999, the first case, a previously healthy 7-month-old girl was admitted to hospital with a 1-day history of watery diarrhoea, vomiting and fever. Physical examination showed a sick child with fever (38.9 C), signs of dehydration, hyperperistalsis and hyperaemia of the throat. Laboratory data on admission included a normal peripheral blood leukocyte count (7200/mm, with 31% neutrophils), normal serum electrolytes and creatinine, and slightly increased levels of liver enzymes (aspartate aminotransferase (AST) 79 U/l, alanine aminotransferase (ALT) 93 U/l) and C-reactive protein (CRP) (18.3 mg/l). Rehydration therapy was instituted immediately and the presumptive diagnosis of viral gastroenteritis was confirmed a few days later by detection of rotavirus antigen in a stool sample. The child remained febrile and 2 days after admission, intravenous cefotaxim (100 mg/kg per day) was started. The fever soon subsided, but at this time the child developed an upper respiratory tract infection. Unexpectedly, on day four Kingella kingae was isolated from a blood culture (BacT/Alert Pedi-Bact bottle, Organon Teknika) drawn on admission. However, the girl never showed any local signs suggestive of septic arthritis, osteomyelitis or endocarditis and a second blood culture (BacT/Alert Pedi-Bact bottle) drawn 2 days after the first remained sterile. Antibiotics were discontinued after 7 days and the patient was discharged 9 days after admission. A follow-up visit 1 week later was completely unremarkable. The second case was an 8-month-old girl who presented to the emergency department in November 2001 with a 14-day history of intermittent fever. Recently, the parents had noticed the girl’s reluctance to use her left leg. At the onset of the fever, the child had shown symptoms of an upper respiratory tract infection. Physical examination showed a mildly sick child with fever (38.7 C) and a swelling of the left knee with tenderness and painful limitation of motion. Laboratory data on admission revealed an increased peripheral blood leukocyte count (17400/mm, with 45% neutrophils) and CRP (17.3 mg/l). An X-ray film of the left knee was normal, but an ultrasound scan revealed some fluid in the bursa suprapatellaris. Aspiration of the knee joint yielded pus. The aspirated fluid was inoculated in a BacT/Alert FA blood culture bottle (Organon Teknika) and was sent to the laboratory for culture. Empiric therapy for septic arthritis with cefotaxim and oxacillin (both 100 mg/kg per day) was started intravenously and the child became afebrile within 2 days. Local inflammatory signs resolved gradually. K. kingae was isolated from the joint fluid but the blood culture (BacT/Alert PF bottle, Organon Teknika) drawn at presentation remained sterile. Oxacillin was discontinued after 11 days, but cefotaxim was continued for the entire 3 week period of hospitalisation. At discharge, oral amoxicillin-clavulanate (50 mg/kg per day) was started for an additional antibiotic therapy of 3 weeks. Follow-up examinations 3 weeks and 4 months later were normal. In June 2002 the third case, a 9-month-old boy, was admitted to hospital because he refused to use his left leg. For some days prior to admission he had shown signs of an upper respiratory tract infection. Physical examination showed a sick child with fever and painful Eur J Pediatr (2003) 162: 530–531 DOI 10.1007/s00431-003-1220-0

Does functional treatment of idiopathic clubfoot reduce the indication for surgery? Call for a widely accepted rating system.

We present our experience of treatment by physiotherapy, continuous passive motion and strapping in a series of 100 clubfeet classified on a scale of severity according to Dimeglio. Twenty-five percent were good after conservative treatment, and 75% required an operation. There were no recurrences or additional procedures. Before the introduction of the functional treatment in our department, 100% required some sort of surgical intervention and 51% required an additional procedure. In comparison with the results published by Dimeglio et al., the greatest discordance is observed in grade 2 clubfeet.

Femoral derotation for increased hip anteversion. A new surgical technique with a modified Ilizarov frame

We describe a technique of femoral derotation osteotomy performed according to the Ilizarov principles of percutaneous corticotomy and fixation with a frame. We performed 24 femoral osteotomies in 16 patients, four with cerebral palsy and 12 with idiopathic femoral anteversion. All had rapid union and there were few complications. The advantages of the method include early ambulation, good control of rotation and axial alignment, and minimal scarring.

Serial bone scintigraphy in Legg-Calvé-Perthes disease: correlation with the Catterall and Herring classification.

Radiographic classifications in Legg–Calvé–Perthes disease are difficult to use in the early stage of the disease. Changes on bone scintigraphy (revascularization versus recanalization pathway) precede the radiographic changes. Our purpose was to study the correlation between serial bone scintigraphy and radiographic classifications in Legg–Calvé–Perthes disease. In 86 patients, 95 hips that presented with Legg–Calvé–Perthes disease in the early stage were followed with serial bone scintigraphy and radiographs. Forty-four hips showed recanalization: pathway A on bone scintigraphy. Of these hips 96% were classified as Herring A or B and 66% as Catterall 2. Thirty-five hips showed revascularization: pathway B on bone scintigraphy. Of this group 82.8% were classified as Herring C and 17.1% as Herring B. All pathway B hips have Catterall 3 or 4. Sixteen hips showed pathway C: regression from pathway A to pathway B. They presented in 56% of cases with Herring B, 44% with Herring C, and in 81% with Catterall 3 or 4 classifications. We can conclude that there is a significant correlation between the vascularization pattern and the radiographic classification of Herring and Catterall.