Radiologic study of disc behavior following compression fracture of the thoracolumbar hinge managed by kyphoplasty: A 52-case series.

INTRODUCTION: Kyphoplasty has proved effective for durable correction of traumatic vertebral deformity following Magerl A fracture, but subsequent behavior of the adjacent discs is unclear. The objective of the present study was to analyze evolution according to severity of initial kyphosis and quality of fracture reduction. MATERIAL AND METHOD: A single-center prospective study included cases of single compression fracture of the thoracolumbar hinge managed by Kyphon Balloon Kyphoplasty with polymethylmethacrylate bone cement. Radiology focused on traumatic vertebral kyphosis (VK), disc angulation (DA) and disc height index (DHI) in the adjacent discs. Linear regression assessed the correlation between superior disc height index (SupDHI) and postoperative VK on the one hand and correction gain on the other, using the Student t test for matched pairs and Pearson correlation coefficient. RESULTS: Fifty-two young patients were included, with mean follow-up of 18.6 months. VK fell from 13.9° preoperatively to 8.2° at last follow-up. DHI found significant superior disc subsidence (P=0.0001) and non-significant inferior disc subsidence (P=0.116). DA showed significantly reduced superior disc lordosis (P=4*10(-5)). SupDHI correlated with VK correction (r=0.32). Preoperative VK did not correlate with radiologic degeneration of the adjacent discs. CONCLUSION: Correction of traumatic vertebral deformity avoids subsidence and loss of mechanical function in the superior adjacent disc. The underlying disc compensates for residual deformity. Balloon kyphoplasty is useful in compression fracture, providing significant reduction of traumatic vertebral deformity while conserving free and healthy adjacent discs. LEVEL OF EVIDENCE: IV.

Failed back surgery syndrome: who has failed?

INTRODUCTION: Failed back surgery syndrome (FBSS) results from a cascade of medical and surgical events that lead to or leave the patient with chronic back and radicular pain. This concept is extremely difficult to understand, both for the patient and for the therapist. The difficulty is related to the connotations of failure and blame directly associated with this term. The perception of the medical situation varies enormously according to the background and medical education of the clinician who manages this type of patient. Eight health system experts (2 pain physicians, 1 orthopaedic spine surgeon, 1 neuro spine surgeon, 1 functional neurosurgeon, 1 physiatrist, 1 psychologist and one health-economic expert) were asked to define and share their specialist point of view concerning the management of postoperative back and radicular pain. Ideally, it could be proposed that the patient would derive optimal benefit from systematic confrontation of these various points of view in order to propose the best treatment option at a given point in time to achieve the best possible care pathway. CONCLUSION: The initial pejorative connotation of FBSS suggesting failure or blame must now be replaced to direct the patient and therapists towards a temporal concept focusing on the future rather than the past. In addition to the redefinition of an optimised care pathway, a consensus based on consultation would allow redefinition and renaming of this syndrome in order to ensure a more positive approach centered on the patient.

Kyphopasty and vertebroplasty.

Vertebroplasty and balloon kyphoplasty are percutaneous techniques performed under radioscopic control. They were initially developed for tumoral and osteoporotic lesions; indications were later extended to traumatology for the treatment of pure compression fracture. They are an interesting alternative to conventional procedures, which are often very demanding. The benefit of these minimally invasive techniques has been demonstrated in terms of alleviation of pain, functional improvement and reduction in both morbidity and costs for society. The principle of kyphoplasty is to restore vertebral body anatomy gently and progressively by inflating balloons and then reinforcing the anterior column of the vertebra with cement. In vertebroplasty, cement is introduced directly under pressure, without prior balloon inflation. Both techniques can be associated to minimally invasive osteosynthesis in certain indications. In our own practice, we preferably use acrylic cement, for its biomechanical properties and resistance to compression stress. We use calcium phosphate cement in young patients, but only associated to percutaneous osteosynthesis due to the risk of secondary correction loss. The evolution of these techniques depends on improving personnel radioprotection and developing new systems of vertebral expansion.

Evaluation of percutaneous surgery in the treatment of thoracolumbar fractures. Preliminary results of a prospective study on 65 patients.

INTRODUCTION: We conducted a prospective, single-center, continuous study of patients operated for fractures urelated to osteoporosis at the thoracolumbar junction level using percutaneous techniques. The aim of this study was to investigate the clinical and radiological outcomes of percutaneous techniques for these indications. PATIENTS AND METHODS: This study included patients who underwent standalone balloon kyphoplasty surgery or combined with percutaneous posterior osteosynthesis in cases of associated distraction. The fractures were classified according to the Magerl classification. The patients were evaluated clinically (visual analog scale [VAS], the Oswestry Disability Index, and autonomy) and radiologically (vertebral kyphosis and height variations of the vertebral body) for 12 months. RESULTS: Sixty-five patients were included. The mean age at the time of the surgery was 45.4 years (range, 19-72 years). The main indications were A.1 fractures of L1. We noted 22% cement leakages, none having a clinical impact. In the overall series, the VAS at the lesional level improved from 5.5 (range, 3-8) preoperatively to 0.6 (range, 1-3) at 12 months. In all, 95% of the workers resumed their occupation. Traumatic kyphosis improved from 13.3° (range, 5-23°) before the surgery to 8.3° (range, 1-20°). DISCUSSION: The complication rate was low. The radiological results are comparable to those reported in the literature for other series with percutaneous surgery. Only the loss of the correction observed in the group undergoing standalone kyphoplasty with calcium phosphate cement led us to propose another type of treatment for these indications. This study must be continued over the long term to detect the appearance of discopathy related to cement leakage and to answer questions as to how cement evolves. LEVEL OF EVIDENCE: III, prospective study with low statistical power.

Vertebral body cage use in thoracolumbar fractures: outcomes in a prospective series of 23 cases at 2 years' follow-up.

INTRODUCTION: One objective of surgery in thoracolumbar spine fracture is to restore correct and lasting spinal statics. This may involve vertebral body replacement using an anterior approach. We here report results on a prospective series of 23 trauma patients managed by vertebral body replacement using an expandable cage. PATIENTS AND METHODS: The sex ratio was 2.28. Fifteen cases involved primary treatment of recent fracture and eight secondary surgery for non-union or malunion. In 12 cases, posterior osteosynthesis was associated. Six patients were operated on using a classical approach and 17 using a video-assisted minimally invasive approach. Pre- and perioperative data were recorded, with clinical scores (VAS and Oswestry) at 6 weeks, 3 months, 6 months, 1 year and 2 years. Radiologic follow-up assessed regional traumatic kyphosis (RTK), enabling calculation of regional traumatic angulation (RTA), with control CT to check fusion. RESULTS: Minimum follow-up was 2 years. There were no cases of postoperative neurological deterioration. There were three major postoperative complications: one hemothorax, one adhesive bowel occlusion, and one bilateral pneumothorax at 1 month. Mean Oswestry score at 6 months was 20%, and mean VAS score at 2 years was 0.36. Postoperative RTA showed a mean 7.34° improvement. Mean RTA reduction loss was 1.95° at 3 months, subsequently unchanged. All arthrodeses showed fusion at 6 months. CONCLUSION: Results were satisfactory with this technique, comparable to those reported in the literature. The development of minimally invasive approaches and improved instrumentation procedures optimize surgery and enhance anterior reconstruction tolerance. Lasting restoration of sagittal spinal curvature improves trauma patients' functional recovery.

Percutaneous internal fixation combined with kyphoplasty for neurologically intact thoracolumbar fractures: a prospective cohort study of 24 patients with one year of follow-up.

INTRODUCTION AND HYPOTHESIS: Neurologically intact lumbar and thoracolumbar fractures are frequent but their treatment is not codified. The purpose of this study was to evaluate the effectiveness of minimally invasive treatment of such fractures by percutaneous fixation associated with balloon kyphoplasty. PATIENTS AND METHODS: Between November 2008 and July 2010, 24 patients were treated. There were 12 men and 12 women, with a mean age of 53 years (range 20-88 years). Fractures were classified as one Magerl lesion type A1, one type A2, 19 A3 (five A31, 10 A32, four A33), and three type B2. The treatment was kyphoplasty of the fractured vertebra followed by percutaneous fixation of the vertebra above and below the fracture. Patient follow-up included an analysis of pain using the visual analogic score, the Oswestry score, and functional X-ray and CT analysis. RESULTS: Surgery lasted a mean 99 minutes. At the last follow-up, the mean pain was scored at 0.9 and the Oswestry score was 13.2. Reduction of vertebral kyphosis was 8.6° and reduction of the corrected regional angle was 7.1°. The gain in vertebral height was 17%. All pedicle screws were positioned correctly and no neurological, septic, or thromboembolic complications were observed. DISCUSSION AND CONCLUSION: Percutaneous osteosynthesis combined with balloon kyphoplasty is a valuable surgical technique in the treatment of thoracolumbar and lumbar fractures with no neurologic deficit. The clinical results are good and the technique allows the patient to return home earlier without having to wear a corset. The X-ray result scores are very encouraging, with corrections similar to conventional surgery in terms of vertebral height and kyphosis. This technique can be an alternative to conventional open surgery. LEVEL OF EVIDENCE: IV: Prospective observational study.

[Scarf osteotomy for the treatment of hallux valgus: a review of 123 cases with 4.8 years follow-up]. / Ostéotomie Scarf dans le traitement de l'hallux valgus: à propos de 123 cas avec un recul moyen de 4,8 ans.

PURPOSE OF THE STUDY: Many different osteotomies can be used for the treatment of hallux valgus. The purpose of this study was to evaluate the Scarf osteotomy associated or not with phalangeal osteotomy and to search for deformation cutoff points beyond which corrections appear to be difficult to achieve. MATERIAL AND METHODS: This retrospective analysis included 87 patients (123 feet) among 130 who underwent hallux valgus surgery between October 1993 and November 2000. Mean follow-up was four years eight months. The serie included 83 women and 4 men. Mean age at surgery was 53.5 years. A Scarf diaphyseal osteotomy was performed in all patients associated or not with phalangeal osteotomy. Each patient was reviewed clinically and radiographically with anteroposterior and lateral views of the foot in the standing position. RESULTS: 84.6% of the patients were satisfied or very satisfied. There was a correlation between the index of satisfaction and clinical symptoms (metatarsalgia, stiff hallux, pain over exostosis). There was a statistically significant decrease in hallux valgus (31.2 degrees to 17.5 degrees ), of metatarsus varus (12.1 degrees to 7.5 degrees ), and articular angle of the distal metatarsus (13.3 degrees to 11.1 degrees ). Patients who had phalangeal osteotomy achieved the best hallux valgus correction (15 degrees versus 21.4 degrees ). Mean shortening of the first metatarsus was 2.2 mm with a decrease in the metatarsus-ground angle (19 degrees versus 20.1 degrees ). Cutoff limits for deformations which are difficult to correct satisfactorily were M1M2 angle > or = 15 degrees and distal metatarsal articular angle > or = 13 degrees . The overall Groulier score showed 70.7% very good and good results, 27.6% fair results and 1.7% poor results. DISCUSSION: The Scarf technique is a reliable method to achieve significant correction of hallux valgus deformation. It requires a rigorous technique with specific attention to the elevation of the first metatarsus and excessive shortening, two factors favoring metatarsalgia. Adding a phalangeal osteotomy can improve the radiological result, but it is very difficult to obtain satisfactory correction if the initial deformations are severe and associated. Rotation of the plantar fragment helps for better orientation of the articular surface of the first metatarsus but limits the correction of the metatarsus varus. Function is the basic objective of hallux valgus surgery and patient satisfaction is related solely to clinical symptoms.

[Biomechanical study and digital modeling of traction resistance in posterior thoracic implants]. / Etude biomécanique et modélisation numérique de la résistance à la traction des implants thoraciques postérieurs.

PURPOSE OF THE STUDY: The purpose of this experimental study was to compare posterior fixation systems using hooks and screws implanted in the thoracic spine. This study was completed by a digital analysis using the finished element method. MATERIAL AND METHODS: For the experimental study, we used 7 human thoracic spines. Forty-nine groups of 2 vertebrae were individualized. Traction was applied to maximum breaking force measured on an Instron. We used two types of instrumentations, alternating 4 pedicle screws and 2 pedicle-lamina hooks. For the digital study, we used a vertebral model composed of nearly 63 000 nodes and 14 000 elements. Elastic field calculations were carried out with a finished element abacus. RESULTS: The base of the pedicles broke when traction was applied to a pedicle-lamina hook assembly. The medial part of the pedicle broke when traction was applied to a pedicle screw assembly. Maximul break strength for hooks was 1 108 +/- 510 N. It was 820 +/- 418 N for 4 mm diameter screws and 1 395 +/- 435 for 5 mm screws. The most fragile vertebrae were T5-T6 and T7-T8. the screw-instrumented model showed that stress concentrated on the medial aspect of the pedicle, inside the medullary canal. Using a long screw did not reduce the stress force significantly. The hook-instrumented model showed that stress was greatest on the lower part of the pedicle. DISCUSSION: From a mechanical point of view, screw instrumentation is the more appropriate type of fixation. Screw fixation did not however demonstrate its superiority during the traction tests. For 4 mm screws, resistance was 23% weaker than with a hook assembly and for 5 mm screws, it was only 12% stronger. Pullout may be attributed to two principal causes, either fracture of the bony anchoring of the screw system or breakage of the pedicle. Bone thread pullout occurs when the screw threads do not penetrate sufficiently deep into the cortical bone due to the small diameter of the screw shaft. Using a larger diameter screw raises however the problem of damaging the pedicle. Pedicle breakage is seen with stronger stress forces and constitutes the upper limit of maximum break force. This leads us to formulate the hypothesis that in most cases, screw pullout occurs by breakage of the bony threading. Screws are less effective if they are not properly anchored in the pedicles, probably the reason for their relative weakness. Screw diameter should be adapted to the size of each pedicle. This would allow better transmission of stress from the screw to the pedicle. Hooks apply further stress to the vertebrae. The digital study showed that using a long screw crossing through the vertebra does not reduce the stress applied to the pedicles enough to justify its use.

[Mid-term behavior of the bone fixation in non-cemented Miller-Galante 1 total knee arthroplasty]. / Comportement à moyen terme de la fixation osseuse de prothèses totales de genou de Miller-Galante 1 implantées sans ciment.

PURPOSE OF THE STUDY: This retrospective work was conducted to analyze the quality of the bone-implant interface at mid-term in 45 cases treated with a non-cemented Miller-Galante 1 total knee arthroplasty. MATERIAL AND METHODS: All the protheses reviewed were implanted without cement. A patellar implant was cemented in 31.1 p. 100 of the cases. Female sex predominated in this series (77.5 p. 100) and the mean age at operation was 67 +/- 6 years. Pre- and postoperative assessment was based on the HSS score. Mean follow-up was 8.3 years (range 7-11 years). We used the method advocated by the International Knee Society to analyze lucent lines on tibial and femoral implants. Non-parametric tests were used for the statistical analysis with a significance level set at 5 p. 100. RESULTS: The mean HSS score rose from 55 +/- 12 preoperatively to 80 +/- 13 postoperatively, with 62.2 p. 100 good or excellent results at last follow-up. One re-operation was required for aseptic loosening. The femoral implant presented a lucent line in 24.4 p. 100 of the cases at the first follow-up examination only. The tibial implant presented an anterior lucent line at the second follow-up examination then a medial line at the last follow-up in 22.2 p. 100 and 26.6 p. 100 of the cases respectively. Presence of a lucent line (tibial or femoral) on at least one view was significantly correlated with activity (p=0.01) and tibial slope (p=0.0087). DISCUSSION: The disappearance of the lucent lines seen on the femoral component at the second follow-up examination was the expression of its secondary integration. Inversely, we observed an evolution in the lines observed on the tibia. This was probably the result of posterolateral impaction and anteromedial ascension micromovements of the tibial component. An excessive tibial slope was statistically related to development of lucent lines. It increased tibial translation on weight bearing and probably induced an abnormal alteration of the polyethylene. We did not observe any case of massive osteolysis of the tibial metaphysis as described in the literature for non-cemented knee arthroplasties. The screws of the Miller-Galante 1 prosthesis do not protrude from the tibial implant (which would risk generating polyethylene debris) and the pieces used (screws and implants) are all made of the same metal. CONCLUSION: The quality of primary fixation of the non-cemented Miller-Galante 1 tibial implant was not totally satisfactory at mid-term. Inversely, simple impaction of the femoral component was sufficient to ensure stable positioning.

Subacromial impingement: influence of coracoacromial arch geometry on shoulder function.

OBJECTIVE: To find correlations between radiological coracoacromial arch geometry and shoulder function in patients with subacromial impingement syndrome. PATIENTS AND METHODS: During a prospective study of the efficacy of arthroscopic subacromial decompression, we evaluated the function of the treated and contralateral shoulders using Constant's functional score and confronted the results to several radiographic parameters reflecting coracoacromial arch geometry. RESULTS: Constant's score values were low (42 +/- 15) because of pain and a low level of activity. Males had significantly higher scores than females. Constant's score was unaffected (P > 0.05) by patient age, the side, the level of activity, or the duration of symptoms, but was significantly influenced by the orientation of the acromion with respect to the scapular spine and to the vertical scapular axis. The preoperative Constant's score was significantly higher in patients with a more horizontal acromion (P = 0.01). A very tight correlation was found between the preoperative Constant's score and the angle between the acromion and scapular spine (P = 0.0003). CONCLUSION: Based on our results, we defined an open and a closed coracoacromial arch geometry. Coracoacromial arch geometry is correlated with shoulder function syndrome and can assist in the interpretation of rotator cuff impingement.

[Brain abscess following the use of skull traction with Gardner-Wells tongs]. / Abcès cérébral secondaire à l'utilisation de traction crânienne par étrier de Gardner-Wells.

Brain abscess after insertion of skull traction is a rare and serious complication. Its development is secondary to superficial infection. Adequate preventive measures have to be taken: proper sterile dressing and daily care. Signs of local irritation are not always synonymous with skull migration. When gradual loosening of the skull occurs, especially associated with superficial infection, the pins must not be tightened. The more appropriate management is to investigate for penetration of the inner cranial cave. When in doubt, repositioning the pins may be necessary, as well as establishing an aggressive treatment against cutaneous infection.

[Acetabular reconstruction using bone allograft in the revision of total hip prosthesis]. / Reconstruction cotyloïdienne par allogreffe osseuse dans les révisions de prothèse totale de hanche.

PURPOSE OF THE STUDY: Aseptic loosening of the acetabular component is the most worrying problem after hip arthroplasty. During revision surgery we prefer to rebuild a solid bony acetabulum close to the anatomy in which the implant will be cemented. On the basis of the first 48 acetabular reconstructions using deep-frozen bony allografts, we carried out a review of our results in a pathology which will surely increase in the future. MATERIAL: 48 hips were operated according to this technique. It has been possible to review 38 of them, with an average follow-up of 7.3 years (extremes 5 years, and 9.6 years). The average age of the population at the time of surgery was 63 years. Two etiologies predominated: congenital hip dislocation sequelae and primitive hip arthritis. In 10 cases of massive deterioration, a Muller's ring was used to stabilize the allograft. METHODS: The results were analyzed at 6 months, 2 years, 4 years, and at maximum follow-up, clinically, according to Merle d'Aubigné grading system. Radiologically, Ranawat's criteria were used to assess the re-centering of the reconstructed hips. The development of radiolucent lines and implants migration were also assessed. RESULTS: Clinically, the patients' comfort was always improved by pain relief. Radiologically, average acetabular upward migration of 5 mm and medialisation of 3.5 mm were observed. 24 hips presented radiolucent lines. 19 radiolucent lines were below 2 mm. 5 were greater than 2 mm and leaded to loosening. In 4 of these 5 cases of radiolucent lines, there were acetabular migrations with failure. The radiological image remained stable afterwards. In these cases there was a real loosening, necessitating further surgery. In all cases, partial resorption of the graft was observed. DISCUSSION: Study of our first 38 cases shows that bony allograft and cemented acetabulum, sometimes including an armature, is one possible solution to the problem of difficult acetabular reconstructions. However, with an average follow-up of 7.3 years, we already have 5 (13 per cent) aseptic acetabular loosening, of which one has been operated on. Radiological analysis of these does not question the allograft, but rather imperfect re-centering. Analysis of the good results, 33 (87 per cent) stable acetabulum indicates re-fixing in quasi-anatomical position, in conditions close to those of a first time arthroplasty, with the aid of perfectly stabilized bony transplants, and where contact with the receiver acetabulum is maximal. CONCLUSION: Our follow-up is one of the longest in literature. But with a migration rate already of 13 per cent, it is not yet sufficient for us to be permanently assured about the future of our patients, even if their age is greater and their activity less than those of patients having a first hip arthroplasty.

Compression of the peroneal nerve by a cyst in a seven-year-old child.

Compressions of the peroneal nerve are rare since only some sixty such cases have been described since 1921. The authors report a new observation of compression extrinsic to the peroneal nerve by a synovial cyst, the source of which was the upper fibulo-tibial joint, in a child of seven years. As far as we know, this is the youngest age found in the relevant literature. Because of a swiftly appearing painful swelling, along with complete paralysis of the peroneal nerve, an electromyogram and a nuclear magnetic resonance were performed, with a view to confirming the diagnosis and to clarifying the topography of the cyst. The removal of the latter led to the child being cured with complete recovery of the peroneal nerve within three months.

[Long-term outcome of Charnley's femoral implant. A review of 309 cases with follow-up of minimum 20 years]. / Comportement à long-terme de l'implant fémoral de Charnley. Revue de 309 dossiers avec un recul minimum de 20 ans.

PURPOSE OF THE STUDY: We evaluated the results of 309 femoral components of total hip arthroplasties performed using Charnley prosthesis and cement, by one surgeon, between January 1972 and December 1975. MATERIAL AND METHODS: Observations and measurements were based on standard pelvic X-rays. Survivorship curves were calculated to evaluate femoral component failures at twenty years of follow-up. We compared the effect of different parameters on the femoral implant loosening. RESULT: At 20 years of follow-up, 82 hips were included in the study, 227 were expelled: 109 by death, 52 by revision and 66 by loss for follow-up. Probability for death, at 20 years follow-up, was 40.7 per cent, probability for revision was 33.9 per cent, for femoral loosening was 16 per cent. The rate of aseptic femoral loosening was higher for men, with high activity and varus position of the femoral stem. Statistical analysis showed correlation between calcar resorption and femoral loosening, between polyethylene wear and calcar resorption. No directly significant correlation was established between polyethylene wear and femoral loosening. DISCUSSION AND CONCLUSION: This study confirms relations between polyethylene wear, calcar resorption and femoral loosening and underlines the influence of mechanical factors on femoral loosening. Femoral stem positioning is very important for femoral loosening. Varus position is clearly unfavourable. According to ours results, the best position is with a slight valgus.

[Reoperations of total hip prosthesis with acetabular reconstruction using bone allografts]. / Les révisions de prothèse totale de hanche par reconstruction cotyloïdienne utilisant des allogreffes osseuses.

Detachment of the acetabular segment is the most important long-term problem with total hip prostheses. We analyzed long-term outcome in our first 48 acetabular reconstructions with cryopreserved allografts. Among the 48 hips operated on with this technique, 38 were reassessed after a mean follow-up of 7 years 3 months (range 5 years-9 years 6 months). Mean age of the population at surgery was 63 years. There were two predominant etiologies: sequelae of chronic hip luxation and primary osteoarthrosis of the hip. In 10 cases with massive destruction, the Müller ring was used to stabilize the allograft. Results were assessed at 6 months, 2 years, 4 years and at longest follow-up using the Merle d'Aubigné clinical assessment scale. For the radiographic assessment, the Ranawat criteria were used to evaluate the alignment of the reconstruction. Clinically, patient comfort was improved in all cases with significant pain relief. Radiologically, mean acetabular ascention was 5 mm and mean medialization was 3.5 mm. A rim was observed in 24 cases including 19 measuring less than 2 cm. Acetabular loosening was evidenced in the 5 other cases where the rim measured more than 2 mm. In 4 of these 5 cases, the acetabulum had migrated to a new setting. The radiographic image then remained unchanged. Analysis of our 38 first cases showed that bone allografts with cimented acetabulum, sometimes with a stabilizing ring, is one of the possible solutions for difficult acetabular reconstructions. However, after a 7 years 3 months follow-up, we have had five (13%) aseptic displacements including one case requiring reoperation. In the 33 stable joints (87%) with good results reconstruction has achieved a nearly perfect anatomic position, similar to first intention arthroplasty with the use of perfectly stabilized bone grafts with a maximal acetabular surface. Our follow-up is longer than most published in the literature. However, the migration rate of 13% it is still too short to draw any conclusion concerning the long-term outcome in our patients, despite their older age and reduced physical activity compared with primary hip arthroplasty patients.

In-vitro biomechanical study of a dorso-lumbo-sacral posterior supple instrumentation with variable section.

This study is designed to analyse the behavior, in the sagittal plane, of a complete human dorso-lumbar rachis, made rigid by the posterior instrumentation used for the treatment of scoliosis, on subjects suffering from DMD (Duchenne Muscular Dystrophy). The object of this analysis is to demonstrate the reliability of early surgery made possible by new instrumentation. Close review of the literature shows that the currently used Harrington or Luque instrumentations lead to mechanical complications, especially rod breaking, at the thoraco-lumbar junction. 8 specimens were non-destructively tested in-vitro. Compression and flexion were applied. For each test, rachis movements with and then without instrumentation, and also rod restraints were noted. The results show a linear stiffness multiplied by 8.3 in flexion and 11.6 in extension. The maximum restraint recorded for physiological displacements is 77 MPa. This remains largely under the fatigue-breaking limit of the metal used (stainless steel hammer-hardened 316 L, Young's modulus = 200,000 MPa, Poisson's ratio = 0.21, endurance limit = 350 MPa at 5 x 10(6) cycles). The results of this study encourage us to continue and develop early surgery in children affected by myopathy, with fixation of the complete rachis, including a lumbo-sacral arthrodesis and a supple dorsal part of the mounting, in the sagittal plane.

[Acetabular implant in Charnley's total arthroplasty. Review of 309 cases with a minimum of 15 years follow-up]. / L'implant cotyloïdien dans l'arthroplastie totale de Charnley. Revue de 309 dossiers avec un recul minimum de 15 ans.

PURPOSE OF THE STUDY: The aim of this study was to appreciate the long term result of 309 acetabular components of total hip arthroplasty. MATERIALS AND METHODS: All were performed using Charnley's prosthesis and cement, by one surgeon, between January 1972 and December 1975. Clinical function was graded according to Postel-Merle-d' Aubigné's scoring system (PMA score). We measured wear of polythylene using a personal method, on anteroposterior radiographs of the pelvis. Radiolucent line were appreciated by Delee and Charnley's criteria, migration by Massin's criteria. Survivorship curves were calculated with radiolucent lines, as migration, on 15 years. We compared the effect of different parameters on wear and loosening of the sockets. RESULTS: At 15 years follow-up, we found 51.5 per cent hips with the highest PMA score (18). Revision for socket loosening was 3.88 per cent, the same for dislocations. Concerning 25 per cent of the sockets, wear of polyethylene was evaluated less than 0.065 mm a year, concerning 50 per cent of them, it was evaluated less than 0.11 mm a year, at last concerning 75 per cent of them, it was evaluated less than 0.16 mm a year. No significant correlation was established between the tilt of the acetabular component and the wear of polyethylene. We observed no radiolucent lines for 60 per cent of the implants, nor migration for 83 per cent of them. Statistical analysis proved the influence of the wear on radiolucent lines and migration. DISCUSSION AND CONCLUSION: The analysis confirms a moderate wear of polyethylene during 15 years. We introduce an original method for its measurement and its formulation. This method allows a truly description of wear in long term results. This analysis confirms also that several parameters intercede on loosening; these are different if one considers radiolucent lines or migration. We do think at last, that the best positionning of the socket in the A.P. view should approach 35 degrees.

[Treatment of unstable fractures of the distal extremity of the radius by Hoffmann's external fixation. Report of 68 cases]. / Traitement des fractures instables de l'extrémité distale du radius par fixateur externe d'Hoffmann. A propos de 68 cas.

Sixty-eight fractures of the distal extremity of the radius, mostly unstable, homogeneously treated by Hoffmann's radio-metacarpal external fixation, were reviewed in terms of functional, objective and radiological criteria. Mean follow-up was 4 years, with a range of 6 months to 10 years. Overall, this treatment achieved 56% of satisfactory results, 26% moderate results and 18% poor results. Open and comminuted fractures give the worst overall results, mostly in terms of functional parameters. From this study, it is clear that external fixation is effective for the treatment of unstable fractures, as it provides good restitution of anatomical integrity of the radius, ensures better stabilization and allows immediate physiotherapy, leading to restoration of a good range of movement. Moreover, compliance with certain technical aspects such as minimal distraction, limits the disadvantages of this technique.

[Compression of the peroneal nerve by a synovial cyst in a 7-year-old child]. / Compression du nerf sciatique poplité externe par un kyste synovial chez un enfant de 7 ans.

PURPOSE OF THE STUDY: Compressions of the peroneal nerve by synovial cysts are rare. Sixty cases have been described since 1921. MATERIALS AND METHODS: It concerns extrinsic compression of the peroneal nerve by a synovial cyst, developed from the upper tibiofibular joint, in a seven years old child. As far as we know, this is the youngest age found in the relevant literature. Because of a swiftly appearing painful swelling, along with complete paralysis of the peroneal nerve, an electromyogram and a magnetic resonance imaging were performed, in view to confirm the diagnosis and to clarify cyst topography. RESULTS: Removal of the cyst led to healing with complete recovery of the peroneal nerve within three months. DISCUSSION: Both intraneural and extraneural cysts exist. Most authors agree that their source is the upper tibiofibular joint. In case of intraneural cysts, complete removal is sometimes impossible. It seems preferable to make a longitudinal incision in the nerve to lay the tumor flat. Indeed, everything possible should be done to find, then ligature, the pedicle which passes by the articular nerve ending of the peroneal nerve in order to avoid recurrence. Extraneural cysts are sometimes intra- or inter-muscular and create a swelling which is often palpable. It is necessary to remove the cyst carefully and to dissociate it from the nerve endings. CONCLUSION: In all cases, recurrence is not infrequent. Longer the delay before intervention is less satisfactory the recovery will be.