Aims

The aim of this study is to test the hypothesis that three grades of sagittal compensation for standing posture (normal, compensated, and decompensated) correlate with health-related quality of life measurements (HRQOL).

Introduction

Although the association between osteoporosis and adolescent idiopathic scoliosis (AIS) has become widely accepted, the mechanism behind the development of osteoporosis and AIS remains unknown. To elucidate this relationship, we investigated the radiological and histological changes in a model of scoliosis in chickens, focusing on the cervical vertebrae that are not affected by scoliosis.

Expandable prostheses were designed to allow progressive growth after tumour resection in children. The aim of this study was to report the late results of the non-invasive growing prostheses designed by A Soubeyran (Phenix prosthesis or Wright Repiphysis).

From 1994 to January 2006, 27 children aged 4 to 12 (mean 8.5), underwent a resection of the knee for a bone tumour, with reconstruction by a non invasive expandable prosthesis. There were 16 boys and 11 girls. The tumours were 25 osteosarcomas and 2 Ewing tumours. All patients received pre and post-operative chemotherapy. There were 18 distal femur, 7 proximal tibia, and 2 femur + tibia resections.

There were different successive designs based on the same electro-magnetic growing mechanism using a pre bent spring, released by eating in an induction coil.

After, 7.2 years mean follow-up (4 months to 15 years), 20 patients had no evidence of disease and 7 were deceased. Two with a local recurrence were amputated. Mean lengthening was 5.1 centimeters (0 to 8), after 3 to 11 lengthening procedures. Mean limb-length discrepancy was 1.8 cm. Two patients had a secondary infection. Eleven had a revision for arthrofibrosis. All surviving patients were revised to a conventional hinged prosthesis. The mean MSTS functional score of the definitive prosthesis was 82% (63 to 96%).

Theses prostheses showed many mechanical complications as loosening, fracture of the growing mechanism, and arthrofibrosis. The positive outcome was the possibility to perform a progressive lengthening, without surgery limiting the risk of infection. Theses prostheses should be considered as temporary until reconstruction with a conventional hinged prosthesis. Patients with multiple revisions had a tendency to show less favourable late functional results than with primary implanted hinged prosthesis.

Purpose of the study: Transfer of a vascularised fibular is an option after tumour resection to save the limb.

Material and methods: Thirty-eight consecutive cases of malignant bone tumours located in the shaft of long bones of the lower limb were treated with a free transfer of a vascularised fibula. There were 30 femoral localisations and 8 tibial localisations, 32 first-intention transfers and six transfers after failure of an allograft. Mean age at transfer was 11.8 years (range 4.33–22.57). Adapted chemotherapy was associated. The Musculo-skeletal Tumour Society score was noted for the functional assessment. Healing was considered achieved when there was a bone bridge between the transplant and the recipient bone associated with disappearance of the osteotomy line. Outcome was expressed as mean or percentage with the 95% confidence interval. P< 0.05 was considered significant.

Results: Mean follow-up for the 38 patients was 7.56 years (range 0.37–18.4). The mean MSTS was 27.2 (range 20–30).. This mean score was significantly higher (S t = 2.11> 2.04) for vascularised fibular transfer surgery immediately after tumour resection (27.4) than after revision surgery (25.4). The healing rate was 89%. The rate of healing failure of the vascularised free transfer was significantly greater (p=0.005< 0.05) after revision (33%) than after immediate transfer (6%). The rate of good results in the Boer classification was significantly higher for tibial than femoral reconstructions (p=0.006< 0.05), for immediate surgery than revision surgery (p=0.005< 0.05), and for Ewing tumours than for osteosarcoma (p=0.0019< 0.05).

Discussion: Free transfer of a vascularised fibula is a reliable reconstruction technique for bone shaft loss of the lower limb after resection of a malignant bone tumour in children. This is a mutilating surgery with frequent complications but which can save the limb. This reconstruction surgery should be done at the same time as the resection. Healing of the vascularised fibular transplant is more difficult to achieve for femoral reconstructions than tibial reconstruction and there are more complications in the femoral localisation. Femoral reconstructions using a vascularised fibular transplant should be associated with an allograft.

Introduction: Accurate and quantitative measurements of the spine are essential for deformity diagnosis and assessment of curve progression. There is much concern related to the multiple exposures to ionizing radiation associated with the Cobb method of radiographic measurement, currently the standard procedure for diagnosis and follow-up of the progression of scoliosis. In addition, the Cobb method relies on two-dimensional analysis of a three-dimensional deformity. The Ortelius800TM aims to provide a radiation-free method for scoliosis assessment in three planes (coronal, sagittal, apical) with simultaneous automatic calculation of the Cobb angle in both coronal and sagittal views. This new device is based on direct measurement of the position of the tips of the spinous processes in space. A low intensity electromagnetic field records the spatial position of a sensor attached to the examiner’s finger while palpating the patient’s spinous processes. This study investigates the correlation of spinal deformity measurements with Ortelius800TM radiation-free system as compared to standard radiographic measured Cobb angles in order to assess Ortelius800TM clinical value while enabling a significant reduction of x-ray exposure.

Methods: 124 patients diagnosed with Adolescent Idiopathic Scoliosis (AIS) from four different medical centers were measured with the Ortelius800TM system using the same standard protocol. The entire process required an average of 2 minutes. The Ortelius800TM measurements were correlated with the standard Cobb angle as measured on routine standing coronal and sagittal radiographs. The Pearson correlation coefficient was calculated for matched pair measurements. The mean difference and the absolute mean difference between measurements with the two methods was estimated.

Results: Standing full-spine coronal radiographs were obtained for each patient. Radiograph analysis for these 124 patients revealed 249 deformity measurements. The deformity measurements were comprised of 142 thoracic curves with a mean of 18.3° and 107 lumbar curves with a mean of 17.4°. Lateral radiographs were obtained from 38 patients with a mean of 36.1°. Correlation between Cobb angles measured manually on standard erect posteroanterior radiographs and those calculated by this new technique showed an absolute difference between the measurements to be significantly less than +\−5° for coronal measurements and significantly less than +\−6° for sagittal measurements indicating good correlation between the two methods.

Pearson’s correlation coefficient between deformity angles obtained by the two methods was highly significant (0.86) with a P value < 0.0001. The measurements from four independent sites were not significantly different.

Discussion: The results reveal good correlation between the two measuring methods in both coronal and sagittal views. We propose the Ortelius800TM as a clinical tool for the routine follow-up measurements of AIS patients, thus enabling a significant reduction of radiation exposure.

Introduction: Mechanical complications following lumbar fixation are due to the combination of various factors related to morphology, pathology, and surgery. The aim of this study was to provide a patient-specific Finite Element Model of the lumbar spine for the simulation of surgical strategies, and to use it as a predictive tool aiming to detect and reduce preoperatively the risks of mechanical complications.

Materials & Methods: A pre-existing 3D personalized FEM of the lumbar spine was used. Posterior implants and main degenerative pathologies were also modelled.

After in vitro validation based on 24 specimens and 4 different instrumentations, the model was used to simulate real cases. Applied loads were based on patient characteristics (weight, imbalance). Simulation results included mechanical stresses in the discs and within the implants.

Clinical consistency of the simulations was tested through the gathering of clinical data for 66 patients instrumented with lumbo-sacral rigid screw-rod systems. Two subsets were considered: “mechanical successes” (53), and “mechanical failures” (13, including 11 screw breakage and 2 screw loosening). Blind comparison was then performed between these observed clinical outcomes and numerical simulations results.

Results & Discussion: Among the 66 patients, simulation results highlighted specific behaviours for 9 patients for which mechanical loads on implants were significantly higher. All of these 9 patients were actual “mechanical failures”. None of the actual “mechanical successes” were associated with “abnormal” simulation results.

Conclusion: This is the first time finite element simulations helped predicting 9 failures out of 13 observed among a total of 66 patients. This is a promising step towards the possibility to use FEM as a clinically relevant simulation tool for surgery planning.

Objective: To clarify whether serum melatonin levels in adolescent idiopathic scoliosis correlate with curve progression, and whether the exogenous melatonin treatment is effective in patients with decreased levels of endogenous melatonin in adolescent idiopathic scoliosis.

Method: A total of 63 adolescents were studied; 38 with adolescent idiopathic scoliosis and 25 age matched control subjects. We divided the patients into stable (28 patients) and progressive (10 patients) groups based on the scoliotic curve measured radiographically at three to six month intervals. The level of melatonin was considered low if it fell below the mean – 2.0 standard deviation established in normal adolescents throughout the 24 hour period or nocturnal (0:00 – 6:00 hour) integrated concentration. Oral melatonin replacement (3mg / before bedding) was administered in patients with decreased endogenous melatonin. The patients with low melatonin were treated with a brace, melatonin or both combined. During melatonin treatment, the level of melatonin was measured yearly for a period ranging from three to six years.

Results: In all subjects the melatonin levels showed diurnal variations; low during the day and high at night. Of 38 patients with adolescent idiopathic scoliosis, 22 patients had normal melatonin and 16 had low melatonin. Of 22 patients with a normal melatonin, 10 of 15 treated with brace and 6 of 7 untreated patients had stable scoliosis, and the remaining six had a progressive scoliosis. Of 16 patients with low melatonin, eight of nine treated only with melatonin, and four of seven treated with melatonin and brace had stable scoliosis. The remaining four had a progressive course. Of the 10 patients who had progressive scoliosis in normal and low levels of melatonin, nine had greater than 40 degrees of curve at the initial examination.

Conclusion: These findings suggest that transient melatonin deficiency may be associated with deterioration of scoliosis and that melatonin level may serve as a useful predictor for progression of spine curvature in patients with idiopathic scoliosis. Also, the results of this study suggest a possible role of melatonin supplement in the prevention of progressive scoliosis especially in mild cases showing less than a 40° curve.

Supported by the Fondation Yves Cotrel, Institut de France.

Introduction: We believe the information given by a new 2D/3D low dose radiation system is useful to the spinal surgeon.

Method: This commercially developed system was evaluated over the past three years. We evaluated 150 patients, with normal controls, using two prototypes. We compared it with a CT scan for accuracy in 2D and 3D reconstruction and for radiation doses.

Results: We found various advantages of this system over CT scanning:

Reductions in radiation exposure of x8 to x10 fold in 2D, and x800 to x1000 in 3D.

Overall it provides a new approach to assessing spinal deformity both in the horizontal plane and in volumetric measurement.

Conclusion: his innovative method is clearly a help for both patients and surgeons.

Purpose of the study: The objective of this work was to achieve a whole-body 3D study of the bone and joint system in the upright position using the lowest radiation dose possible. Radiation doses can be considerable when acquiring 3D images using computed tomographic millimetric sections which in addition are acquired uniquely in the reclining position and thus limited to a specific region.

Material and methods: Using a gas detector which transforms x-ray protons into electrons (G. Charpak) we constructed a device which enables acquisition of high-quality anteroposterior and lateral whole-body radiographic images with exposure to radiation doses 8 to 10-fold less than classical 2D x-rays. A 3D reconstruction of the entire skeleton was obtained from these two initial images.

Results: The 3D reconstructions were validated and compared with those obtained with computed tomography. The results were concordant and revealed least equivalent to if not better reliability. The advantage was to enable study in the functional upright position an to study weight-bearing joints of the lower-limbs, pelvis, and spine. In addition, radiation exposure for the 3D reconstructions was reduced 800 to 1000 times compared with computed tomography. More than 150 examinations have been performed and validated in patients with diverse pathological conditions as well as in normal control adults and children.

Discussion: There is a very wide potential field of application for this technique in orthopedics, both for 3D analysis of joint deformations and their impact on the whole body, and for therapeutic follow-up, particularly after prosthetic or corrective surgery. For example, the horizontal plane which is very difficult to image and represent mentally for spinal surgery can be clearly planned and controlled. This new imaging technique offers perspectives for intraoperative navigation and for bone mineral density measurements. The double-energy methodology enables short-term evaluation of fracture risk due to osteoporosis of the spine and limbs or pelvis.

Purpose of the study: We wanted to assess long-term outcome after treatment for Ewing tumor of the pelvis.

Material and method: We reviewed 62 patients aged 5 to 28 years treated from 1983 through 1993. There were 35 males and 27 males. Sixteen patients had pulmonary metastases at diagnosis. Patients were given chemotherapy using three protocols (Ew 84, Ew 88, Ew 93) proposed by the French Society of Pediatric Oncology. Fourteen patients were give high-dose chemotherapy with a bone marrow graft. The local treatment was not randomized. Radiotherapy was used alone in 25 patients and 15 underwent surgery and radiotherapy. Eighteen underwent surgery without complementary radiotherapy. For patients were not given local treatment. Outcome at last follow-up was assessed retrospectively.

Results: Mean follow-up was 6.6 years (3 months to 18 years); 29 patients were in remission, 6 had progressive disease, and 27 had died. Two patients who had bone marrow grafts developed a second tumor in the radiated territory. The overall chances of survival were 55±6% at five years and 53±7% at ten years. There was no significant difference by type of chemotherapy. In the group of operated patients, the five year survival was 68% versus 43% in the group of non-operated patients (p=0.007). In patients with initial metastases, chances of survival at ten years were 19.7±10% versus 65.9±7% in patients without metastasis. Only two patients who presented metastases initially were in remission at last follow-up. Five patients developed local recurrence after surgery and none had been radiated despite incomplete response to chemotherapy or presence of contaminated resections.

Discussion: Rigorous comparison between operated and non-operated patients is hindered due to the different indications. Results of treatment of Ewing tumors of the pelvis without metastasis are comparable to those obtained for tumors in other localizations. The fact that a second tumor can develop in the radiated territory is a particularly important factor in patients given high-dose chemotherapy with a bone marrow graft.

Conclusion: Surgical treatment appears to improve local control of Ewing tumors of the pelvis. If initial metastasis is not present, the prognosis appears to be similar to other localizations. Radiotherapy remains and indispensable adjuvant in the event of surgical resection or incomplete response to chemotherapy.

Purpose: Prevalence of supracondylar fractures above a total knee arthroplasty (TKA) is increasing due to the increasing age of treated patients and the larger number of implants. We report the functional results in a series of thirteen patients treated with a distal femoral graft (DFG) associated with revision TKA.

Material and methods: Between 1990 and 2001, thirteen patients (twelve women and one man), mean age 65 years (24–93) were treated with DFG associated with revision TKA. All fractures were type III using the Lewis classification and involved severe osteoporotic bone associated with loosening of the femoral piece. Before fracture, the patients had had two operations on average (1–4). The fracture occurred as a result of a fall in nine patients, low-energy trauma in three, and during mobilisation under general anaesthesia in one. The functional results were noted prospectively using the modified HSS score and the SF-36 quality-of-life questionnaire. Radiographic assessment of bone healing and implant stability was performed by two independent observers (kappa=0.75, p=0.02).

Results: At mean follow-up of 60 months (12–144), the mean HSS score was 75 (64–86). Mean knee flexion was 100° (50–115°). One patient required subsequent amputation due to infection. Using our classification, functional outcome was good or excellent in seven patients, fair in four and poor in two. For nine patients, x-rays showed no sign of loosening. In three patients, there was minimal to moderate periprosthetic bone resorption.

Discussion: Treatment of periprosthetic fractures of the knee is a therapeutic challenge. Osteoporosis and comminution is a complex association making stable osteo-synthesis difficult with conventional methods. Massive knee prosthesis using a DFG and a standard TKA is an attractive alternative. This technique allows restoration of the bone stock by bone healing and constitutes a less aggressive therapeutic solution.

Conclusion: Despite the risk of infection, we believe that composite prostheses can be an attractive option for the treatment of periprosthetic supracondylar fractures of the knee.

Purpose: Amputation is often proposed for malignant tumours of the distal tibia. The purpose of our study was to report outcome and complications after conservative treatment of osteosarcoma of the distal tibia.

Material and methods: Eight patients, four boys and four girls aged 8 – 16 years (mean 12 years) were managed conservatively with high-dose methotrexate chemotherapy for osteosarcoma of the distal tibia between 1983 and 1998. Wide resection was performed in all cases and one patient had a lung metastasis. Mean length of resection was 13 cm (9–19). Tibiotalar reconstruction arthrodesis was performed in seven patients. Tibial grafts and a centromedullar nail associated with fibulotalar arthrodesis with screw fixation were used in four patients. Plate fixation was used in two, and one patient had a cement spacer while waiting for biological reconstruction. After surgery, the patients were immobilised in a plaster cast for three to six months. Weight bearing began two to four months after surgery.

Results: Resection was wide in four cases, marginal in three , and contaminated in one. Four patients responded well to chemotherapy and four responded poorly. Outcome was assessed at a mean follow-up of 5.5 years (2–17 years). At last follow-up, six patients were in remission, and two had died, including one after local recurrence despite amputation. Three patients had a deep infection which cured in all three without surgery. Two revisions were required in one patient with nonunion before achieving a solid union. All the patients who had a tibiotalar arthrodesis progressively developed nearly normal “ankle” function subsequent to progressive sub-talar hypermobility. The mean MSTS score was 27.7/30 (range 22 – 30).

Discussion: Conservative management of osteosarcoma of the distal tibia appears to be feasible and provides excellent functional results despite an important risk of infection. Wide surgical margins requires a good response to chemotherapy. In case of doubt, reconstruction must avoid contaminating the rest of the tibia in order to allow secondary amputation if needed.

Purpose: Infection after resection and total knee arthoplasty for malignant bone tumours in children is a serious complication which may compromise limb salvage. The purpose of this work was to study the aetiology, treatment and prognosis of this event.

Material and methods: Among the 169 total knee arthroplasties performed for malignant bone tumours between 1981 and 1999, we selected 17 patients meeting the following criteria: proven infection with identified germ on deep samples or presence of a fistula more than two years after surgery. All of the patients had osteogenic sarcomas (excluding Ewing sarcomas which account for 30% of the tumours in this localisation). The bone tumour involved the femur (n=11) or the tibia (n=6) and required extraarticular (n=14) or transarticular (n=2) resection. Infections were primary (n=9) developing after the first operation, or secondary (n=8) to surgical revision in six, joint wound in one, or haematogeneous dissemination in one patient. The causal germ was identified in thirteen patients (76%) and was a staphylococcus in all cases. Treatment included systemic antibiotics and lavage (n=10), one-procedure change in prosthesis (n=3), removal of the implant with replacement by a spacer (n=2), surgical abstention (n=2), or amputation (n=1).

Results: Mean follow-up was eight years (2 – 16 years). On the average, treatment of infection lasted 51 months and required a 3.9 surgical interventions. At last follow-up, infection was considered cured in 70% of the patients who were free of clinical or laboratory signs of infection without antibiotics for at least one year. The arthroplasty could be preserved in one-third of the cases (22% of the primary infections and 50% of the secondary infections). Another treatment, arthrodesis (n=6), Borggreve procedure (n=1), or amputation (n=4), was given in the other two-thirds.

Discussion: The 10% complication rate observed here is in agreement with data in the literature. Development of primary infection is influenced more by the histology of the tumour and the presence of skin wounds (methotrexate) than by tumour site or type of resection. The diagnosis of primary infection is made late, often at the end of the postoperative chemotherapy protocol. Changing the implant is the ideal treatment. Secondary infection is characteristically less difficult to diagnose; infection is recognised earlier and the chances of preserving the implant are better.

Purpose: Therapeutic options for shaft reconstruction are allografts, shaft prosthesis, and autografts, which may be vascularised or not. The purpose of this work was to assess mid-term results and complications after upper limb reconstructions using a vascularised fibula in children and adolescents undergoing surgery for tumour resection.

Material and methods: A vascularised fibular graft was used for reconstruction in ten patients who underwent surgery for resection of upper limb tumours between 1994 and 2000. The patients were seven boys and three girls, aged seven to seventeen years. the vascularised fibula was used for reconstruction after tumour resection in the same operation for eight patients and to salvage a proximal humeral prosthesis in two patients. The eight single-procedure reconstructions concerned four resections of the humeral shaft and four resections of the radius. Tumour histology was: classical osteosarcoma (n=7), low-grade osteosarcoma (n=1), Ewing tumour (n= 1) and aggressive enchondroma (n=1). Six patients were on chemotherapy at the time of the fibular transfer.

Graft lengths varied from nine to 21 cm (mean 14 cm). Plate fixation was used in most cases. All patients wore a cast for six to twelve weeks after surgery.

Results: Results were analysed retrospectively after 3.9 years follow-up (range 1 – 7 years). Mean time to bone healing was three months (range 1.5 – 5 months). Five of the six humeral shaft reconstructions fractured due to trauma, requiring revision surgery in four cases. All patients who were reoperated achieved bone healing rapidly. One radius had to be revised to add supplementary bone. The mean functional score (MSTS) was 25.5/30 (range 21 – 30). One patient died from lung metastasis and the others exhibited complete tumour remission.

Discussion: Vascularised fibula reconstruction of the upper limb provides good radiological results, particularly for the radius. For the humerus, the results are better for younger children because the bone can grow in thickness. Certain mechanical complications may occur if normal sports activities are resumed too early. Functional outcome after these shaft reconstructions is nearly normal.

Purpose: Use of massive knee prostheses in the treatment of malignant tumours allows excellent short-term oncological and functional results. The purpose of our work was to demonstrate that these good early results later require several revisions.

Material and methods: From 1981 to 1986, 48 patients, mean age 13.8 years (9–19) were treated for osteosar-coma of the knee by chemotherapy and resection. Six patients had metastases at the time of diagnosis. Resection involved the distal femur in 34 cases, the proximal tibia in 13 and both extremities in one case. Mean resection was 20 cm (12–29). Reconstruction was achieved with a cemented GUEPAR. Twenty of the initially implanted prostheses had a rotatory mechanism. Reconstruction of the diaphyseal segment was generally achieved with massive metal or polyethylene prostheses and in three cases with a prostheses sleeved on an allograft. After resection of the proximal tibia, reconstruction of the extensor system was achieved with the vastus medialus.

Results: Results were assessed retrospectively at a mean follow-up of eleven years (4 months – 20 years). Seven patients were lost to follow-up. At last follow-up of available patients, 34 were in remission, 14 had died, giving an actuarial survival rate at 15 years of 72%. For the 48 prostheses initially implanted, seven were revised for loosening, four became infected (two secondarily), four femoral stems fractured and two rotatory mechanisms fractured. All the prostheses followed more than three years required at least one surgical revision. Only eight of the initially implanted prostheses are still in situ after 15 years, giving an actuarial survival probability of 39±17%. Certain prostheses were changed four times. If all revisions are included, the 32 surviving patients have had 84 prostheses. Most of the recent revisions were indicated for hinge wear and to avoid changing the inserts within too short an interval. At last follow-up, one patient has undergone amputation, one has a rota-tionplasty, and one has an arthrodesis, all for infection. The functional results at last follow-up are good or excellent in 19 cases, fair in five, poor in three and could not be evaluated in 21 (14 deaths and seven lost to follow-up).

Discussion: Reconstructions using massive prostheses are associated with a high rate of mechanical complications making surgical revision inevitable. These complications are mainly due to wear of the hinge itself. The use of better designed prostheses in terms of mechanical properties should reduce the rate of mechanical complications. When the tumour extension spares the epiphysis, use of biological, non-prosthetic reconstruction methods should be preferred.

Methods and results: From the last 15 years, we have observed 18 cases from various aetiologies of compression of the airway by the “billot” created by the protrusion of the vertebral bodies inside the thoracic cage. This status lead to atelectasia intermittent or permanent with subsequent recurrent lung infection and sometimes abscesses with impairment of the respiratory function perfectly demonstrated by CT scan as well as with bronchoscopy showing extrinsic bronchi stenosis. Such pathology necessitates an anterior vertebral body resection for decompression of the airway done in 15 patients and sometimes partial lung removal lobectomy done in 4 cases. Subsequently repeated lung infection disappeared in all cases but vital capacity only improved by 2%.

Discussion: This pushed us to study this point and to propose a new 3D entity called spinal penetration index seen as well on regular CT scan cut of the chest as on 3D volumetric reconstruction representing the amount of vertebral, rib, soft tissues and sometimes empty space protruding inside the thoracic cage. This presented as an endothoracic vertebral hump compared to the exothoracic classical rib hump. Compared to normal subject where the amount is less than 10%, it can reach 50% in some severe scoliotic cases. The deformity is evident and can be quantified easily with a computer programme. Done today with regular CT scan cuts at rest, in the near future this will be obtained with regular stereographic X-rays in a much less invasive manner with low dose radiation.

Conclusion: The spinal penetration index measure in 3D is the amount of protrusion of the spine and surrounding tissues inside the thoracic cage. It is an anatomical parameter entering into the measurement on the useful thoracic volume for breathing given by the thoracic skeleton. It is very different from vital capacity where diaphragm, joints, muscle function play an important role. This concept allows to quantify in 3D the results of surgery of the spine in a much better way for 3D consideration than the classical Cobb angle. It helps also for analysis of the chest for example before and after thoracoplasty and allows to classify the rib hump and the vertebral hump in a logical way with their therapeutic consequences.

Purpose of the study: To analyse post-operative imbalance after C.D.I. (Cotrel Dubousset Instrumentation) for idiopathic scoliosis according to the fused area, particularly the lower level of fusion. To recall a classification for determination of fusion area based on pre-operative standing coronal radiograph.

Patients and methods: To be included in this study the patients had to have an adolescent idiopathic scoliosis, at least two years of post-operative follow up. One hundred and twenty-two patients met the criteria; mean follow-up was three years, five months (minimum two years, maximum nine years). Scoliotic curves were classified as single structural (81), double structural (41). Balance was clinically analysed by plumbline, radiographically by a plumbline dropped from C7 to the sacrum and measuring deviation from the midpoint of the sacrum in centimetres. A curve with a deviation of 10 mms or less was considered as balanced.

Results: Imbalance in single structural curves was 70% when using stable vertebra (King) or “other vertebra” (beyond stable vertebra or one or two levels upper stable vertebra). Using end vertebra (J.MOE), (elected vertebra – C. Salanova) imbalance was 10%. In double structural (41 cases) imbalance was 50% using stable, or “other vertebra” 10% when elected vertebra was fused.

Conclusion: In this study there was a strong statistical relationship between the lower level of fusion and imbalance.

Failure of massive knee endoprostheses implanted for malignant tumours of the distal femur in children presents a difficult problem.

We present the results of rotationplasty undertaken under these circumstances in four boys. They had been treated initially at a mean age of 9.5 years for a stage-IIB malignant tumour of the distal femur by resection and implantation of a massive knee endoprosthesis. After a mean period of eight years and a mean of four operative procedures, there was failure of the endoprosthesis because of aseptic loosening in two and infection in two. Function was poor with a mean Musculoskeletal Tumor Society score of 7.5/30, and considerable associated psychological problems.

At a mean follow-up of 4.5 years after rotationplasty there was excellent function with a mean score of 27.5/30 and resolution of the psychological problems.

Purpose of the study: Advances in chemotherapy protocols over the last 20 years have considerably improved the prognosis and functional outcome in patients with osteogenic sarcoma. We report here the results of a cooperative study conducted under the auspices of the French Society of Pediatric Oncology (SFOP). Twenty-nine oncology centers participated in this retrospective national multicentric study.

Materials and methods: The study included 15 .3 patients with osteogenic sarcoma of the limb who were treated by the OS87 protocol with conservative surgery between 1987 and 1994. The OS87 protocol consisted in conservative or nonconservative surgery combined with pre- and postoperative chemotherapy. The following inclusion criteria were used: age under 20 years, tumor localization in a limb (pelvis and spine excluded), no metastasis at diagnosis, biopsy proven osteogenic sarcoma.

Results: Mean age at diagnosis was 13 years. The knee localization predominated (80 p. 100). 82.5 p. 100 of the patients had grade IIB disease (Enneking classification). For the 187 patients included in the protocol surgery was nonconservative in 20 p. 100 of the cases and conservative in 80 p. 100. The choice of the surgical technique (arthroplasty, allograft, autograft, resection without reconstruction) depended on the patient’s age and school situation. Data analyzed here concerned only those patients who had conservative treatment. Mean follow-up was 64 months. The actuarial survival curve plateaued at 71 p. 100 at more than 6 years. Early and late complications were numerous and variable (mechanical, infectious, local recurrence). Secondary amputation was required in 10 p. 100 of the patients. The overall functional outcome of the preserved limbs was nevertheless good with rapid restoration of self-sufficiency despite major surgery and a high number of reoperations (about 65 p. 100 of cases).

Discussion: In light of the frequency and the seriousness of the complications, these results are modest. Patients and family should be advised of the risk, particularly the risk of secondary amputation which may be required early due to contaminated excision or at mid term due to major non-cancerological complications. As survival has been improved, functional capacity must be preserved for several years. This orients surgery towards more “biological” reconstruction which can provide greater longevity than arthroplasty.

We studied the possible role of melatonin deficiency in experimentally-induced scoliosis. A total of 90 chickens underwent pinealectomy on the third day after hatching: 30 were treated with serotonin, 30 with melatonin and 30 received no therapy (control group). Scoliosis developed in all the control group, in 22 of the serotonin group, and in only 6 of the melatonin group. The six melatonin-treated chickens with scoliosis had less severe spinal deformities than those in the serotonin-treated group. There were lower blood melatonin concentrations in chickens with scoliosis than in those without. Our findings suggest that melatonin deficiency contributes to the aetiology of this experimental scoliosis, probably by interfering with the normally symmetrical growth of the proprioceptive system involving the paraspinal muscles and the spine.