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Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_34 | Pages 172 - 172
1 Dec 2013
Simon P Diaz M Schwartz D Santoni B Frankle M
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Introduction:

The complex 3D geometry of the scapula and the variability among individuals makes it difficult to precisely quantify its morphometric features. Recently, the scapular neck has been recognized as an important morphometric parameter particularly due to the role it plays in scapular notching, which occurs when the humeral component of a reverse shoulder arthroplasty (RSA) prosthesis engages the posterior column of the scapula causing mechanical impingement and osseous wear. Prosthetic design and positioning of the glenoid component have been accepted as two major factors associated with the onset of notching in the RSA patient population. The present image-based study aimed to develop an objective 3D approach of measuring scapular neck, which when measured pre-operatively, may identify individuals at risk for notching.

Materials and Methods:

A group of 81 subjects (41 M, 69.7 ± 8.9 yrs.; 40 F, 70.9 ± 8.1 yrs.) treated with RSA were evaluated in this study. The 3D point-cloud of the scapular geometry was obtained from pre-operative computed tomography (CT) scans and rendered in Mimics. Subsequently, a subject-specific glenoid coordinate system was established, using the extracted glenoid surface of each scapula as a coordinate reference. The principal component analysis approach was used to establish three orthogonal coordinate axes in the geometric center of the glenoid. Utilization of glenoid-specific reference planes (glenoid, major axis, and minor axis plane) were selected in order to remove subjectivity in assessing “true” anterior/posterior and profile views of the scapula. The scapular neck length was defined as the orthogonal distance between the glenoid surface and the point on the posterior column with the significant change of curvature (Fig. 1). In addition, the angle between the glenoid plane, area center of the glenoid, and the point of significant change of the curvature were assessed (Fig. 2). This new parameter was developed to serve as a predictive critical value for the occurrence of notching. The incidence of notching increases as the value of the notching angle decreases. In order to evaluate relationships between glenoid and scapular neck, the glenoid width and height was also measured at the glenoid plane.


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_34 | Pages 536 - 536
1 Dec 2013
Simon P Virani N Diaz M Teusink M Santoni B Frankle M
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Introduction:

Subchondral bone density (SBD) distribution is an important parameter regarding that may be important when considering implant stability. This parameter is a reflection of the loading experienced by the joint throughout the lifetime and may be useful in pre-surgical planning and implant design. Clinically, the question of the glenoid surface preparation for TSA/RSA remains controversial, despite numerous published studies on glenoid bone morphology. To address this question, there exists a need to develop a 3D quantitative method capable of analyzing the complex glenoid bone morphology at different depths from the surface. Computed tomographic osteoabsoptiomery (CT-OAM) evaluates SBD based on the Housfield Unit (HU) value of each pixel. In this pilot study, we aimed to analyze SBD distribution of the glenoid at different depths by means of CT-OAM in male TSA subjects.

Materials and Methods:

A study group of twenty male TSA patients (61–69y.o) were included in this study. Each subject obtained a pre-operative CT scan following a standardized protocol on the same CT scanner (1.25 mm slice thickness). Resultant DICOM 2D images were processed in custom-written program (VC++) and the surface of every glenoid was manually traced from the axial slices. Care was taken during the manual tracing process to exclude osteophytes and cyst formations from the resultant surface. Values of HU at every selected pixel on the surface of the glenoid were recorded. Subsequently, the layer of pixels at a 0.5 mm distance from the previous surface was virtually scraped and the HU values of new layer of pixels were recorded. This routine was repeated up to a depth of 5 mm from the glenoid surface, taking measurements on 11 virtual 3D surfaces with a thickness of 0.5 mm. Mean SBD distribution was reported for each layer and differences were compared using ANOVA and Fisher's post-hoc test.


Orthopaedic Proceedings
Vol. 93-B, Issue SUPP_IV | Pages 533 - 533
1 Nov 2011
Schneider L Di Marco A Simon P
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Purpose of the study: Biphasic macroporous phosphocalcium ceramics are used in routine surgery to fill bone defects. This type of material presents the characteristics of an ideal substitute: free of the adverse effects of grafts, biocompatibility, bioactivity, osteoconduction, osteointegration, reproducibility, availability in sufficient quantity. The purpose of our work was to evaluate the role of osteointegration on the resistance of two macroporous biphasic phosphocalcium ceramics routinely proposed on the French market. These two macroprous materials have a similar chemical composition but vary by the presence or not of interpores.

Material and methods: The experimental model involved the implantation of ceramic cylinders in a femoral cortical site in sheep, via the intermediary of conduction chambers with specific cortical entrances. The resistance to compression of the implanted samples an non implanted controls was measured using the same ISO norms.

Results: After two months implantation in a cortical site in the sheep, Eurocer200plus® exhibited a significant 38% increase in resistance to compression while in the same conditions, Triosite® exhibited a 41% decline in resistance. For ceramics with open porosity, the interpores acted like tunnels enabling rapid colonization for osteoforming cells and early formation of new bone reaching the centre of the substitute, and leading to increased material resistance. Cell colonization of a ceramic with closed porosity is, on the contrary, slowed by the partitions, while its dissolution by biological fluids within the micropores occurs in all materials; there results an imbalance between absorption and synthesis, leading to loss of mechanical resistance as a first phase of osteointegration.

Discussion: Open macroposity enables an improvement in the mechanical properties of a biphasic ceramic substitute due to more rapid osteointegration. In the future, material associated with osteoinduction cells or proteins should play an important role, together with changes in the architecture of the ceramic skeleton which should play a determining role in terms of physical and biological properties.


Orthopaedic Proceedings
Vol. 90-B, Issue SUPP_II | Pages 235 - 235
1 Jul 2008
CHIFFOLOT X AOUI M BOGORIN I SIMON P COGNET J STEIB J
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Introduction: Surgical treatment of thoracolumbar spine fractures from T11 to L2 with correction of the traumatic kyphosis should be expected to avoid the deceptions observed with former treatments.

Material and methods: Seventy trauma victims (41 men and 29 women) underwent surgery between 1996 and 2003. According to the Denis classification, they presented: 16 compressions, 43 burst fractures, 8 seat belt fractures, and 3 disclocations. The Frankel classification was E:62, A:2, C2, D:2. Mean follow-up was 30.7 months. A pedicle screw protected with sublaminal hooks below and pediculotransverse claws above was used in 50 patients with a hybrid configuration in 20. Reduction was achieved by in situ cerclage. A secondary anterior graft was implanted for 38 patients.

Results: Patients were allowed to rise without contention on day 3. The traumatic angle measured with the sagittal index of Farcy (SIF) (the quality parameter used to study reduction) was 17 preoperatively and 1.6 after surgery. The loss at last follow-up was −2.2° with 81% of patients presenting normal or over correction. The loss was greatest (5.2°) for uniquely posterior approaches. The final Oswestry score was 29.8 (range 6–80) with a better result for the double approaches (20.7 versus 37.4, p< 0.001). Complications were phlebitis (n=1), sutured dural breaches (n=2), disassembly and nonunion (revision with a double approach) (n=1), infection (treated by wash-out and antibiotics) (n=10), retroperitoneal hematoma (treated by embolization) (n=1). Thirty-two patients resumed their work at seven months on average and 13 did not (25 without professional occupation).

Discussion: The overall results are better than those after orthopedic treatment. The rate of resumed work was 71%. This is an excellent result with a less aggressive treatment protocol (no corset) and shorter hospital stay (5–19 days). The protective hooks facilitate in situ cerclage, avoiding catching the screws and the risk of disassembly. The anterior graft is necessary when the reduction is discal and reduces the angle loss leading to less morbidity.

Conclusion: In situ cerclage enables constant sustained reduction of thoracolumbar fractures. Indication for surgery is often retained because of major deformation. Spinal fractures should be examined with the same assessment criteria as used for fractures of long bones and weight bearing should begin early to avoid the risks associated with prolonged bed rest.


Orthopaedic Proceedings
Vol. 90-B, Issue SUPP_II | Pages 284 - 284
1 Jul 2008
COGNET J GEAHNA A MARSAL C KADOSH V GOUZOU S SIMON P
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Purpose of the study: We report our experience with the LCP DRP 2.4 plate with a locking screw for the treatment of distal factures of the radius.

Material and methods: Between 2003 and June 2004, 67 displaced fractures of the distal radius were treated with a LCP DRP 2.4 system. Patients were subsequently immobilized in a removable anatomic orthesis for three weeks. The Fernandez, Castaign and AO classifications were used. Clinical evaluation was based on the DASH test, the Green and O’Brien score and the PWRE.

Results: Clinical assessment was available for 59 patients who also responded to the questionnaires. Mean follow-up was eight months. Healing was achieved in six weeks. There were no cases of secondary displacement nor of lost reduction. The mean Green and O’Brien assessment was 85% good and very good outcome, the mean DASH score was 20.6 and the mean PWRE was 32.8.

Discussion: Appropriate fixation for fractures of the distal radius remains a controversial issue, as illustrated by the variety of treatments used, the different materials proposed for fixation, and the large number of publications. The primary stability achieved with the locking screw in the LCP plate enables early rehabilitation. The absence of secondary displacement, irrespective of the quality of the bone, enables equivalent results in osteoporotic patients as in younger patients. No other material has enabled equivalent results to date. This is a major advance in osteosynthesis.


Orthopaedic Proceedings
Vol. 90-B, Issue SUPP_II | Pages 284 - 285
1 Jul 2008
COGNET J EHLINGER M MARSAL C KADOSH V GEAHNA A GOUZOU S SIMON P
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Purpose of the study: Since 2001, we have used arthroscopy systematically to control the treatment of distal radius fractures. We report our three years experience.

Material and methods: Arthroscopic control was used for all patients aged less than 65 admitted to our unit for treatment of an articular fracture of the distal radius. The same operator performed all procedures. Fixation methods were: K-wire pinning, locked plating (Synthes) or a combination of these two methods. The arthro-scope had a 2.4 mm optic. Bony lesions were noted according to the Cataign, Fernandez and AO classifications. The DASH, Green and O’Brien, and PWRE scores were noted.

Results: Intraoperative arthroscopic control was performed for 61 patients between November 2001 and November 2004. Mean follow-up was 17 months (range 6–36 months). Arthroscopic exploration revealed: scapholunate ligament tears (n=11), lunotriquetral ligament injuries (n=3), pathological perforations of the triangle complex (n=4), damage to the radial cartilage (n=15), and mirror involvement of the carpal cartilage (n=4). An arthroscopic procedure was necessary to treat a bone or ligament lesion in 28 cases. At last follow-up, the DASH score was 19.3 and the PWRE 37.6.

Discussion: Arthroscopic evaluation of articular fractures of the distal radius, a routine practice in English-speaking countries, remains a limited practice in France. There is nevertheless a real advantage of using intraoperative arthroscopy. The particular anatomy of the radial surface makes it impossible to achieve proper assessment on the plain x-ray for a quality reduction of the fracture. Recent ligament injuries are rarely detectable on a wrist x-ray. An intra-articular stair-step or an untreated ligament injury can pave the way to short-term development of osteoarthritic degeneration. Intraoperative arthroscopic control is the only way to diagnosi and treat these osteoligamentary lesions observed in patients with an articular fracture of the distal radius. For us, non use of intraoperative arthroscopy constitutes a lost chance for patients with an articular fracture of the distal radius.


Orthopaedic Proceedings
Vol. 87-B, Issue SUPP_II | Pages 110 - 110
1 Apr 2005
Ehlinger M Chiffolot X Cognet J Le Coniat Y Dagher E Simon P
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Purpose: We report preliminary results after treatment of humeral fracturs with a Targon centromedullary nail (Aesculap(r)).

Material and methods: Forty-five patients, predominantly women, underwent surgery from June 2001 to June 2002. Mean age was 63.5 years. The right side predominated. The series included 28 proximal fractures (65.9 years): 3-4 fragments (n=14), two fragments (n=8), pathological fracture (n=3),metaphyseo-diaphyseal fracture (n=3); and 17 shaft fractures (59.5 years): pathological fractures (n=4), nonunion (n=3), trauma (n=10). The Beach position, fractured limb free, was used with a superolateral approach. We inserted 28 Targon PH nails, including nine long nails, for proximal fractures and 17 Targon H nails for shaft fractures. Nail diameter was 8 mm. Nails were locked with four self-locking proximal screws (5 mm) and two distal screws (3.5 mm). The patients were immobilised with an arm to body brace. Hanging limb exercises were initiated immediately and active exercises at bone healing. The Constant score and radiographic measures were recorded at last follow-up.

Results: Mean follow-up was 12.2 months. We had six deaths and five patients lost to follow-up. Bone healing was achieved at eight weeks on average. Fracture reduction was acceptable for 37 limbs, including three which required open reduction. There were nine postoperative complications: superficial infection (n=1), distal screw pull out (n= 3), distal screw fracture (n=1), nail fracture (n=1). The mean Constant score was 69 (30–96).

Discussion: Proximal fractures of the humerus are often comminuted displaced fractures requiring cephalic arthroplasty. Total functional recovery is often difficult leading to mid and long-term problems for this young population. Stable quadruple proximal locking, associated with good filling of the canal by the nail enables fracture stablisation and satisfactory maintenance of the tuberosities. This stable assembly allows early rehabilitation. These advantages are particularly important for shaft fractures in young patients. The material does however have certain limitations related to fragility of the distal screws which are situated near the circumflex bundle for the Targon PH nail.

Conclusion: Our early results are encouraging for humeral fractures, both in elderly and young patients. This type of osteosynthesis can be a useful alternative to arthroplasty and allows early rehabilitation necessary for good functional recovery.


Orthopaedic Proceedings
Vol. 84-B, Issue SUPP_I | Pages - 61
1 Mar 2002
Simon P Delloye C Bressier F Nyssen-Behets C Banse X Babin S Schmitt D
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Purpose: Only very partial integration of massive allografts is generally achieved, affecting bone-graft junctions and the peripheral cortical. In clinical practice, this is not a major problem for massive reconstructions with a sleeve prosthesis but can be a handicap for junctional grafts or osteoarticular grafts where weak recolonisation can be a source of complications.

Material and methods: Extraperiosteal resection measuring 5 cm in length was made in the mid shaft region and bridged by a cyropreserved non-irradiated allograft before stabilisation with a static locked nail. Three groups of ten sheep were studied. The first group received a simple allograft without perforation; the allograft was perforated in the second group (1.1 mm drill bit); and the perforations in the allograft in the third group were lined with decalcified bone powder with assumed potential for inducing bone growth. The implantation was studied after a delay of six months. There were three infections so the analysis was made on 27 grafts. Plain x-rays (consolidation of the graft-bone junctions), histomorphometrics (porosity, new peripheral and endomedullary bone deposit, cortical thickness), and bone density were studied.

Results: Rate of bone-graft consolidation was not significantly different in the three groups. The callus was more endosteal in groups 2 and 3 (p< 0.02) and endomedullary bone deposit was greater (p=0.0001) than in group 1 without perforation. There was approximately three times more bone deposit in the perforated allografts than in the non-perforated allografts; Adjunction of demineralised bone around the perforated grafts did not lead to any significant difference compared with the perforated allografts (group 2).

Discussion: Significantly more bone deposit observed with perforated allografts should lead to better biomechanical behaviour. This is being tested in further work.

Conclusion: Perforations induce a significant increase in new bone deposit in massive cortical allografts, remodelling is much more active and extensive than with non-perforated allografts. It would be logical to propose perforated allografts for junctional or osteochondral massive cortical grafts.