Pierre-Emmanuel Ridon
email: pierre.emmanuel.ridon@gmail.com

Sophie Putman

Henri Migaud

Charles Berton

Gilles Pasquier

Julien Girard

Long-term comparative study of large-diameter metal-on-metal bearings: Resurfacing versus total arthroplasty with large-diameter Durom™ bearing

Introduction

Short-term results in total hip arthroplasty (THA) with large-diameter metal-on-metal (MoM) bearings were encouraging, but high failure rates have been reported in the long term, notably implicating corrosion due to modularity. Several studies compared resurfacing (to which modularity does not apply) versus large-diameter MoM THA; but, to our knowledge, none compared the same bearing in the two situations with more than 10 years' follow-up.

We therefore conducted a retrospective case-control study, using a single cup model (Durom™, Zimmer, Warsaw, USA) for both resurfacing (R) and large-diameter THA, to determine the role of modularity in failure of large-diameter MoM bearings. The study compared 1) metallic ion levels, and 2) survival, functional scores and complications rates between R and THA.

Hypothesis

Large-diameter MoM bearing failure implicates not bearing wear but head-neck junction modularity in larger-diameter MoM THA.

Material and Method

83 THAs and 90 Rs were included between February 2004 and March 2006. All patients had clinical and radiologic follow-up with chromium (Cr) and cobalt (Co) ion blood assay.

Results

In the THA group, 24 of the 83 patients (28.9%) underwent revision for adverse reaction to metal debris (ARMD), versus none in the R group. Ten-year all-cause survival was significantly better in R (97.7%; 95% CI, 96.2-99.2) than THA (67.1%; 95% CI, 60.9-73.3). Median blood ion level was higher in THA (with a difference between Co and Cr: 5.75µg/L (range, 3.82-19.2) versus 1.75µg/L (range, 1.34-2.94) respectively) than in R (no difference: 0.89 μg/L (range, 0.67-2.89) and 1.07 μg/L (range, 0.67-1.65) respectively). In the THA group, there were positive correlations between Co and Cr elevation and implant revision (both p<0.0001). Co/Cr ratio was significantly higher in THA (2.57) than R (0.88) (p<0.0001), and higher again in the 24 cases of THA revision (4.67). There was no significant difference in mean PMA score (THA: 17.08 ± 1.82 (range, 7 -18); R: 17.50 ± 0.74 (range, 15 -18)), whereas mean Oxford score was better in R (14.32 ± 2.5 (range, 12 -24)) than THA (18.17 ± 8.05 (range, 12 -42)) (p=0.02).

Discussion

The present study confirmed the incontrovertible implication of modularity in failure of large-diameter MoM THA, by analyzing the same bearing in THA and in resurfacing.

Trunnionosis was observed in the 24 cases of revision, with the THA adaptation ring inducing serious metallic ion release (with dissociated Co/Cr ratio), accounting for the high rate of revision.

Introduction

In the 2000s, progress in tribology led to the use of 2 nd -generation metal-on-metal (MoM) bearings in large-diameter arthroplasty (>36 mm) to improve implant survival and reduce dislocation risk [START_REF] Delay | Is there any range-of-motion advantage to using bearings larger than 36mm in primary hip arthroplasty: A case-control study comparing 36-mm and large-diameter heads[END_REF]. Resurfacing (R) thus gained a new lease of life. Large-diameter total hip arthroplasty (THR), initially developed exclusively for revision of resurfacing, came to be widely used in first line [START_REF] Delay | Is there any range-of-motion advantage to using bearings larger than 36mm in primary hip arthroplasty: A case-control study comparing 36-mm and large-diameter heads[END_REF]. Application in THA allowed the advantages of a large diameter without the technical difficulties of resurfacing. Some 500,000 large-diameter MoM arthroplasties have been performed in the last 15 years worldwide [START_REF] Skinner | Medicines and Healthcare products Regulatory Agency: report of the expert advisory group looking at soft tissue reactions associated with metal-on-metal hip replacements[END_REF]. Short-to mediumterm results were encouraging [START_REF] Berton | The Durom large diameter head acetabular component: early results with a large-diameter metal-on-metal bearing[END_REF][START_REF] Lons | Excellent short-term results of hip resurfacing in a selected population of young patients[END_REF][START_REF] Reito | Repeated metal ion measurement in patients with bilateral metal on metal (ASR TM ) hip replacements[END_REF], but national registries [START_REF] Graves | A multinational assessment of metal-on-metal bearings in hip replacement[END_REF][START_REF] Hannemann | European multidisciplinary consensus statement on the use and monitoring of metal-on-metal bearings for total hip replacement and hip resurfacing[END_REF] reported high rates of bearing failure in the long term [START_REF] Hjorth | Does a titanium sleeve reduce the frequency of pseudotumors in metal-on-metal total hip arthroplasty at 5-7years follow-up?[END_REF].

Many studies have compared THA and resurfacing, and some compared large-diameter THA and resurfacing [START_REF] Vendittoli | Metal ion release from bearing wear and corrosion with 28 mm and large-diameter metal-on-metal bearing articulations: a follow-up study[END_REF][START_REF] Lhotka | Four-year study of cobalt and chromium blood levels in patients managed with two different metal-on-metal total hip replacements[END_REF][START_REF] Brodner | Serum cobalt levels after metal-on-metal total hip arthroplasty[END_REF][START_REF] Maezawa | Seven years of chronological changes of serum chromium levels after Metasul metal-on-metal total hip arthroplasty[END_REF][START_REF] Witzleb | Exposure to chromium, cobalt and molybdenum from metal-on-metal total hip replacement and hip resurfacing arthroplasty[END_REF], but either follow-up was no more than 10 years or the two implants were different [START_REF] Johnson | Metal ion levels in total hip arthroplasty versus hip resurfacing[END_REF][START_REF] Langton | Blood metal ion concentrations after hip resurfacing arthroplasty: a comparative study of articular surface replacement and Birmingham Hip Resurfacing arthroplasties[END_REF][START_REF] Hug | The withdrawn ASR TM THA and hip resurfacing systems: How have our patients fared over 1 to 6 years?[END_REF][START_REF] Beaulé | A prospective metal ion study of large-head metal-on-metal bearing: a matched-pair analysis of hip resurfacing versus total hip replacement[END_REF][START_REF] Lainiala | Higher blood cobalt and chromium levels in patients with unilateral metal-on-metal total hip arthroplasties compared to hip resurfacings[END_REF]. We therefore conducted a retrospective case-control study with more than 10 years' follow-up, using the same cup (Durom™, Zimmer, Warsaw, Indiana, USA) in resurfacing (R) and large-diameter THA, to determine the role of modularity in largediameter MoM bearing failure. The study compared 1) metallic ion levels, and 2) survival, functional scores and complications rates between R and THA. The study hypothesis was that large-diameter MoM bearing failure is due not to bearing wear but to the excessive stress involved in large-diameter MoM THA head-neck junction modularity. (Zimmer, Warsaw, Indiana, USA). All procedures were performed on a posterolateral approach by the same team for both resurfacing and THA.

Material and method.

Patients

Assessment

All patients were assessed by a single examiner not involved in the surgery. Implant survival was defined by change for all causes. Clinical assessment comprised: Postel-Merle D'Aubigné (PMA) [START_REF] Aubigné | Numerical classification of the function of the hip[END_REF], Harris [20], Devane [START_REF] Devane | Three-dimensional polyethylene wear of a press-fit titanium prosthesis. Factors influencing generation of polyethylene debris[END_REF], Charnley [START_REF] Charnley | The long-term results of low-friction arthroplasty of the hip performed as a primary intervention[END_REF] and Oxford-12 hip scores [23], and screening for cam effect [START_REF] Marchetti | Component impingement in total hip arthroplasty: frequency and risk factors. A continuous retrieval analysis series of 416 cup[END_REF], lower-limb length discrepancy and dislocation. All patients had AP weight-bearing pelvic X-ray. Cup inclination was measured against the radiologic U line.

Blood sampling for ion assay was from a peripheral vein, using a hollow BD Vacutainer Eclipse Blood Collection Needle with metal-free dry tube. The first 5 ml was discarded to avoid contamination. Chromium (Cr), cobalt (Co) and titanium (Ti) concentrations were measured on inductively coupled plasma (ICP) mass spectrometry (Varian 820-MS; Bruker, Wissembourg, France) with collision cell to eliminate spectroscopic interference. Any high levels were checked in the laboratory and, if confirmed, a second sample was taken a few weeks later. The detection threshold was 0.05µg/L and the quantification threshold 0.1µg/L.

Statistical analysis

Quantitative variables were reported as mean and standard deviation or median and interquartile range; distribution was checked graphically and on Shapiro-Wilk test.

Qualitative variables were reported as number and percentage.

Ion concentrations and Co/Cr and Co/Ti ratios were compared between groups on multivariate linear regression with age [START_REF] Vendittoli | Metal ion release from bearing wear and corrosion with 28 mm and large-diameter metal-on-metal bearing articulations: a follow-up study[END_REF], body-mass index (BMI) [START_REF] Vendittoli | Metal Ion release with large-diameter metal-on-metal hip arthroplasty[END_REF], gender [START_REF] Vendittoli | Metal ion release from bearing wear and corrosion with 28 mm and large-diameter metal-on-metal bearing articulations: a follow-up study[END_REF], acetabular cup inclination [START_REF] Langton | The effect of component size and orientation on the concentrations of metal ions after resurfacing arthroplasty of the hip[END_REF] and femoral implant size [START_REF] Langton | The effect of component size and orientation on the concentrations of metal ions after resurfacing arthroplasty of the hip[END_REF] as adjustment factors. Ion concentration distribution was non-normal and was converted to log values so as to apply a parametric multivariate model. Survival was defined by all-cause revision surgery for implant change. The significance threshold was set at 5%. Analysis used SAS software, version 9.3 (SAS Institute, Cary, NC, USA).

Results

During the inclusion period, 103 large-diameter MoM THAs were performed; 20 hips were excluded from analysis (12 hips in 6 patients with bilateral arthroplasty, 7 deaths, 1 loss to follow-up), leaving 83 THAs. Ninety resurfacings were performed, with no exclusions (Table 1).

Median Co, Cr and Ti levels were significantly (p<0.0001) higher in THA (Figure 1 Twenty-four patients showed Co >7µg/L and 4 showed Cr >7µg/L, all in the THA group (29% and 5%, respectively).

Co/Cr ratio was significantly (p<0.0001) higher in THA: 2.57, versus 0.88 (i.e., close to 1); likewise, Co/Ti ratio was 1.04 versus 0.24 (p<0.0001).

In the subgroup of 24 THA revisions for ARMD, mean Co level was 10.23 ± 3.98 µg/L (range, 0.36-16.8), and mean Co/Cr ratio 4.67 ± 2.91 (range, 0.36-11.26), with systematic macroscopic corrosion around the adaptation ring.

Twenty-four THA patients underwent revision for complications due to local ARMD, and none in the resurfacing group. Ten-year all-cause survival was significantly better (p<0.0001) in resurfacing: 97.7% (95% CI: 96.2-99.2) versus 67.1% (95% CI: 60.9-73.3) (Figure 2).

There was positive correlation (p<0.0001) between Cr, Co and Ti ion elevation (taken separately) and/or dissociated Co/Cr ratio (with greater Co elevation) on the one hand and THA revision on the other. Median cup inclination was 49° (range, 46°-52°) in resurfacing and 50° (range, 46°-55°) in THA (p=0.12), and < 50° in 63 resurfacings (70%) and 45 THAs (54%).

There was no correlation between cup inclination and ion levels: Co (p= 0.18), Cr (p=0. [START_REF] Aubigné | Numerical classification of the function of the hip[END_REF]), Ti (p=0.65), Co/Cr ratio (p=0.56).

All functional scores improved significantly in both groups (p<0.0001), with no significant intergroup difference in PMA (p=0.92) or Harris score (p=0.65), while Oxford score was significantly better in resurfacing (p=0.029) (Table 2). There were no cam effects in either group. There was 5-10mm limb length discrepancy in 5% of THA patients and none with resurfacing. There were no dislocations; there were 2 periprosthetic fractures (1 Vancouver B2 in THA, and 1 cervical fracture in resurfacing), 2 infections in THA, and 1 head collapse in resurfacing.

Discussion

The present study compared metallic ion release between two types of large-diameter MoM arthroplasty, with identical implants and long follow-up (Table 3). Survival was significantly better with resurfacing (97.7%) than THA (67.1%) (Figure 2). High failure rates with Durom large-diameter MoM THA are also reported elsewhere: Althuizen et al. [START_REF] Althuizen | Early failures in large head metal-on-metal total hip arthroplasty[END_REF] reported a 10year revision rate of 14.2% (range, 5.5-22.8%), and Ng et al. [START_REF] Ng | Perspectives in managing an implant recall: revision of 94 Durom Metasul acetabular components[END_REF] 31%. With a 33% rate at around 9 years, and 28.9% of failures implicating the implant, the present results are in accordance with other studies at shorter follow-up [START_REF] Lhotka | Four-year study of cobalt and chromium blood levels in patients managed with two different metal-on-metal total hip replacements[END_REF][START_REF] Long | Failure of the Durom Metasul acetabular component[END_REF][START_REF] Illgen | Large-head metal-on-metal total hip arthroplasty using the Durom acetabular component at minimum 1-year interval[END_REF][START_REF] Lardanchet | One-year prospective comparative study of three large-diameter metal-on-metal total hip prostheses: serum metal ion levels and clinical outcomes[END_REF] (Table 4). Survival in resurfacing was likewise comparable to literature reports (Table 5). Interestingly, the THA and resurfacing groups were comparable in terms of low dislocation rates and increased joint range of motion, commonly attributed to large-diameter arthroplasty.

Co, Cr and Ti ion levels were significantly higher in THA. Titanium is present on the THA femoral stem and in the cup coating, and passive surface corrosion [START_REF] Vendittoli | Metal ion release from bearing wear and corrosion with 28 mm and large-diameter metal-on-metal bearing articulations: a follow-up study[END_REF] would explain ion release in both groups and the higher level in THA due to surface corrosion of the femoral stem (which does not exist in resurfacing). Cobalt and chromium are present in THA heads, cups and rings [START_REF] Lardanchet | One-year prospective comparative study of three large-diameter metal-on-metal total hip prostheses: serum metal ion levels and clinical outcomes[END_REF]; the higher level in THA with Co/Cr ratio dissociation argues for an implication of modularity by trunnionosis, in agreement with Goldberg et al. [START_REF] Goldberg | A multicenter retrieval study of the taper interfaces of modular hip prostheses[END_REF], who showed that cobalt and chromium were released in case of severe corrosion. The chromium remains localized around the Morse taper, whereas cobalt is released into the blood, whence the higher level of blood cobalt and dissociation of the Co/Cr ratio.

Implant design was identical in the two groups, as was cup inclination and femoral diameter: thus, these factors do not account for the observed differences. Release by prosthetic neck/cup contact is not implicated, as no impingement was seen and, biologically, the Co/Ti ratio was not lower, due to Ti release at the implant neck, in THA. There was a significant correlation in the present study between failure and elevated ion levels and Co/Cr ratio, although this is controversial in the literature [START_REF] Robinson | Metal ion levels and revision rates in metal-onmetal hip resurfacing arthroplasty: a comparative study[END_REF][START_REF] Langton | The clinical implications of elevated blood metal ion concentrations in asymptomatic patients with MoM hip resurfacings: a cohort study[END_REF]. Langton et al. [START_REF] Langton | The clinical implications of elevated blood metal ion concentrations in asymptomatic patients with MoM hip resurfacings: a cohort study[END_REF] reported a correlation between ion elevation and failure, while other authors [START_REF] Robinson | Metal ion levels and revision rates in metal-onmetal hip resurfacing arthroplasty: a comparative study[END_REF] found no significant correlation.

The present study had certain limitations. It was a level III retrospective study; however, all patients were examined by a single observer who had not performed the surgery. There may have been measurement biases in ion assay, with inter-individual differences in transportation time and time to analysis; however, the measurement protocol was routine for the follow-up of resurfacing and large-diameter MoM THA. There was also a risk of contamination of the probe in the ICP-MS apparatus if the previous sample contained a high metal concentration; however, this risk was slight, as a second analysis was made in case of abnormally high assay results. Adjustment was made for recognized sociodemographic confounding factors: age [START_REF] Vendittoli | Metal ion release from bearing wear and corrosion with 28 mm and large-diameter metal-on-metal bearing articulations: a follow-up study[END_REF], gender [START_REF] Vendittoli | Metal ion release from bearing wear and corrosion with 28 mm and large-diameter metal-on-metal bearing articulations: a follow-up study[END_REF] and BMI [START_REF] Vendittoli | Metal Ion release with large-diameter metal-on-metal hip arthroplasty[END_REF]. Finally, there was a significant difference in mean follow-up, but only of 9 months: the running-in phase for Metasul™ is between 1 and 4 years [START_REF] Vendittoli | Metal ion release from bearing wear and corrosion with 28 mm and large-diameter metal-on-metal bearing articulations: a follow-up study[END_REF][START_REF] Lhotka | Four-year study of cobalt and chromium blood levels in patients managed with two different metal-on-metal total hip replacements[END_REF], and a 9-month difference should not affect ion levels, taking account of the running-in period.

Conclusion

The present study confirmed the importance of modularity in large-diameter MoM THA failure. Via trunnionosis, adaptation rings induce large ion release, accounting for the high revision rates. THA and resurfacing both target young active patients, with comparable functional scores and dislocation rates. Resurfacing now provides excellent clinical results and survival, and is logically indicated, whereas large-diameter THA, with its excessively high failure rate, has been abandoned.

A

  single-center retrospective comparative study included all patients undergoing hip arthroplasty, whether resurfacing or THA, with a Durom™ cup (Zimmer, Warsaw, Indiana, USA), between February 2004 and March 2006. Inclusion criteria comprised: age <70 years, with >10 years' life-expectancy at surgery. Exclusion criteria comprised: known metal allergy, other concomitant metallic implants, and kidney failure; there were no contraindications regarding femoral head diameter in the resurfacing group. The acetabular component consisted in all cases of a Durom™ cup. The femoral component was a Metasul™ Resurfacing Durom™ head in the resurfacing group and, in the THA group, a Metasul™ LDH Durom™ head, Protasul™ adaptation ring and Alloclassic™ Zweymuller stem

  ): Co, 5.75 µg/L (range 3.82-19.20) versus 0.89 µg/L (range, 0.67-2.89); Cr, 1.75 µg/L (range, 1.34-2.94) versus 1.07 µg/L (range, 0.67-1.65); Ti, 5.70 µg/L (range, 4.10-6.80) versus 4.22 µg/L (range, 3.50-4.90).

Figure 1 :Figure 2 :

 12 Figure 1: Box-plot of Cobalt and Chromium levels in resurfacing (R) and total hip arthroplasty (THA)

Figure 1 :

 1 Figure 1: Box-plot of Cobalt and Chromium levels in resurfacing (R) and total hip arthroplasty (THA)

Table 3: Review of the literature. Comparison of MoM release between large-diameter THA and resurfacing, with identical implants.

Funding:

The study received no specific public, private or non-profit sector funding.

Disclosure of interests

None of the authors have disclosures relating to the present article. Elsewhere, Henri Migaud is a consultant for Zimmer-Biomet, Corin, MSD and SERF and associate editor of


Camille Echalier
email: camille_echalier@live.fr

Julien Uhring

Julie Ritter

Pierre-Bastien Rey

Emmanuelle Jardin

Séverin Rochet

Laurent Obert

François Loisel

Camille Echallier

Évaluation des variations proprioceptives de la ceinture scapulaire chez le sujet sain. À propos de 44 cas

Résumé :

Introduction :

Mieux connaître la proprioception de l'épaule saine permettrait d'améliorer la prise en charge thérapeutique et rééducative de l'épaule pathologique. Plusieurs méthodes visent à évaluer la sensibilité de position articulaire (SPA) mais elles sont souvent coûteuses et complexes. Balke et al. ont proposé un test simple. En utilisant cette méthode de mesure, l'objectif primaire était d'isoler les facteurs pouvant influencer l'évaluation de la SPA au niveau de la ceinture scapulaire chez des sujets sains. L'objectif secondaire était de proposer un système de valeurs de références à partir de l'ensemble des mesures en prenant en compte ces éventuels facteur de variabilité.

Patients et méthode :

Une évaluation prospective monocentrique continue a été menée de septembre 2012 à janvier 2013. La capacité à reproduire une position donnée a été évaluée sur chacune des deux épaules saines de sujets volontaires selon le protocole de Balke. Le sujet étant debout sur une ligne au sol distante de 1m d'une cible murale sur laquelle était repérée 3 angles (55°, 90° et 125°), il devait mémoriser et reproduire en abduction, puis en flexion, les 3 positions (55°,90° et 125°) à 3 reprises. L'écart entre l'angle visé et l'angle effectivement réalisé était mesuré en valeur absolu de degrés et désigné sous le terme de « déviation ». L'âge, le sexe et le membre dominant étaient colligés.

Résultats :

Quatre-vingt-huit épaules chez 44 patients ont pu être analysées. Il n'y avait pas de différence significative entre les sexes (p>0,05). Seule la flexion à 55° était significativement mieux reproduite par le membre dominant (p=0,03). En analyse univariée, seul l'âge était significativement associé à la présence d'une erreur de position (p = 0.003) mais le membre dominant et le sexe ne l'étaient pas (respectivement p = 0.29 et p = 0.59). En flexion, la déviation augmentait avec l'amplitude de façon significative. Les différentes mesures réalisées ont permis d'établir un tableau des valeurs de déviation attendues dans une population saine en prenant en compte l'âge, le type de mouvement et son amplitude.

Discussion:

Le test de Balke est simple et utilisable en pratique courante. L'influence de l'âge, du caractère dominant et du secteur de mobilité est à prendre en compte lors de l'évaluation d'une épaule pathologique. D'autres études sont nécessaires avec un plus grand nombre de patients afin de mieux connaître les valeurs normales de déviation attendues en fonction de ces facteurs. Depuis plusieurs années, la médecine du sport porte un intérêt croissant concernant la sensibilité proprioceptive de l'épaule. En effet, il a été montré que la présence d'un déficit proprioceptif pouvait être à l'origine de lésions musculo-squelettiques et sa persistance à l'origine de récidives [START_REF] Lephart | Proprioception of the shoulder joint in healthy, unstable, and surgically repaired shoulders[END_REF]. Disposer d'outils de mesure permettant l'évaluation de la proprioception s'est donc avérer nécessaire afin de pouvoir juger de l'efficacité d'un traitement chirurgical et/ou rééducatif.

Niveau de preuve : IV

Mots

La proprioception peut se diviser en sensibilité de position articulaire (SPA), kinesthésie et sensibilité de résistance. Actuellement, les tests développés s'attachent à évaluer la SPA et nécessitent souvent une instrumentation spécifique, souvent coûteuse et parfois difficile à mettre en oeuvre [START_REF] Contu | Proprioceptive assessment in clinical settings: Evaluation of joint position sense in upper limb post-stroke using a robotic manipulator[END_REF][START_REF] Ager | Shoulder proprioception: How is it measured and is it reliable? A systematic review[END_REF]. Tester la SPA en mobilité active en donne un reflet plus précis de par la contraction musculaire produisant des signaux afférents, participant à la stabilité et présente dans les gestes de la vie quotidienne [START_REF] Lin | Errors in Shoulder Joint Position Sense Mainly Come from the Glenohumeral Joint[END_REF]. En utilisant cette méthode de mesure, l'objectif primaire de cette étude était d'isoler les facteurs pouvant influencer l'évaluation de la SPA au niveau de la ceinture scapulaire chez des sujets sains. L'objectif secondaire était de proposer un système de valeurs de références à partir de l'ensemble des mesures en prenant en compte ces éventuels facteur de variabilité.

Patients et Méthodes

Une évaluation prospective monocentrique continue a été menée pendant 4 mois

Résultats

Population :

Quatre-vingt-huit épaules chez 44 patients ont pu être analysées (tableau 1). La série comprenait 23 hommes (52,3%) et 21 femmes (47,7%). L'âge moyen était de 31,5 ans (16-54 ans). Il y avait 39 droitiers (88,6%) et 5 gauchers (11,4%).

Analyses statistiques :

Quel que soit le mouvement et l'amplitude, il n'y avait pas de différence significative entre les sexes (figure 2). Concernant le caractère dominant du membre évalué (figure 3

Valeurs de référence

Les différentes mesures réalisées ont permis d'établir un les valeurs déviation attendues dans une population saine en prenant en compte l'âge, le type de mouvement et son amplitude (tableau 2). Cette étude montre que l'âge est un facteur influençant les résultats de l'évaluation de la SPA de la ceinture scapulaire par la technique de Balke. Nous avons pu également répertorier les valeurs normales de déviation attendues pour une population saine.

Discussion

Il n'y a, à ce jour, pas de méthode consensuelle pour la mesure de la proprioception de l'épaule et de nombreux protocoles ont été décrits [START_REF] Ager | Shoulder proprioception: How is it measured and is it reliable? A systematic review[END_REF]. Plusieurs travaux [START_REF] Hantes | Arthroscopic Findings in Anterior Shoulder Instability[END_REF][START_REF] Durban | Anterior Shoulder Instability with Concomitant Superior Labrum from Anterior to Posterior (SLAP) Lesion Compared to Anterior Instability without SLAP Lesion[END_REF][START_REF] Clavert | Glenoid labrum pathology[END_REF] [START_REF] Aydin | Shoulder proprioception: a comparison between the shoulder joint in healthy and surgically repaired shoulders[END_REF][START_REF] Zuckerman | The effect of instability and subsequent anterior shoulder repair on proprioceptive ability[END_REF]. A noter qu'il semble néanmoins qu'après un premier épisode de luxation gléno-humérale antérieure, une intervention chirurgicale ne permet pas d'améliorer les résultats sur la proprioception [START_REF] Edmonds | The effect of early arthroscopic stabilization compared to nonsurgical treatment on proprioception after primary traumatic anterior dislocation of the shoulder. Knee surgery, sports traumatology, arthroscopy[END_REF].

Les tests proprioceptifs évaluant la SPA qui ont été utilisés étudiaient des séries de faible effectif, aux caractéristiques épidémiologiques restreintes (sujets jeunes exclusivement) ne prenant pas en compte les variations inter-et intra-individuelles.

Le protocole d'évaluation de Balke [START_REF] Balke | The laser-pointer assisted angle reproduction test for evaluation of proprioceptive shoulder function in patients with instability[END_REF] est une méthode simple, peu coûteuse, ne nécessitant pas d'équipement spécifique et qui présente une fiabilité intra-observateur satisfaisante [START_REF] Ager | Shoulder proprioception: How is it measured and is it reliable? A systematic review[END_REF]. Elle nous a permis dans cette étude d'évaluer à plus grande échelle la SPA gléno-humérale chez le sujet sain et d'établir un élément de comparaison futur pour les épaules pathologiques (conflit glénoïdien, instabilité, récupération post-opératoire) ou après traitement de ces dernières.

La modification des capacités proprioceptives avec l'âge peut être en partie expliquée par la fatigabilité musculaire [START_REF] Iida | The effect of fatigued internal rotator and external rotator muscles of the shoulder on the shoulder position sense[END_REF]. Il est tentant de penser que plus on vieillit, plus la fatigue musculaire est exacerbée. Il faudrait pouvoir comparer des groupes d'âges différents mais aux capacités physiques identiques. Ne serait-il pas logique de vouloir supprimer ce biais de fatigue musculaire en testant la SPA par des mouvements passifs ? Les muscles seraient alors simplement les effecteurs de la proprioception et non du mouvement. Cependant, il semble que ce recours ne soit pas suffisant car la proprioception est moins efficace lors de la mobilisation passive plutôt qu'active, les muscles en étant effecteurs lorsqu'ils sont contractés [START_REF] Lin | Errors in Shoulder Joint Position Sense Mainly Come from the Glenohumeral Joint[END_REF][START_REF] Lonn | Replication and discrimination of limb movement velocity[END_REF].

Comme précédemment publié (1, 12), le sexe n'influence pas de manière significative la SPA. Hommes et femmes peuvent donc être comparés sans distinction.

Les résultats semblent meilleurs pour le membre dominant mais il n'a pas été mis en évidence de différence statistiquement significative, excepté dans le secteur de flexion 55°.

  Clés : Epaule ; Proprioception ; Test proprioceptif ; Sensibilité de position articulaire ; Instabilité Introduction La ceinture scapulaire est un complexe biomécanique mobile et particulièrement instable de par sa configuration anatomique. Différentes structures participent, passivement et activement, à sa stabilité dynamique et plusieurs travaux (1-5) ont souligné l'existence d'un système proprioceptif en leur sein grâce à la présence de mécanorécepteurs spécifiques (Golgi, Pacini et Ruffini). On les retrouve dans les structures articulaires, ligamentaires, tendineuses et cutanées. Ces organes proprioceptifs sont potentiellement altérés en cas de lésion comme par exemple une rupture de coiffe des rotateurs ou une instabilité gléno-humérale (6, 7).

  Balke et al. (12) ont proposé un test d'évaluation de la SPA simple et peu coûteux, ne nécessitant pas d'instrumentation spécifique et réalisable en pratique quotidienne.

(

  septembre 2012 -janvier 2013) au CHRU de Besançon. Les auteurs ont mesuré la capacité à reproduire une position donnée pour chacune des deux épaules de sujets volontaires. Il s'agissait de sujets sans antécédent (constitutionnel ou acquis) sur la ceinture scapulaire, donc sans limitation des amplitudes articulaires activo-passives, et sans scapulalgies. Une information orale et écrite était fournie. Les mesures étaient effectuées par le même examinateur selon le protocole établi par Balke (7) (figure 1). Le sujet était debout sur une ligne tracée au sol distante de 1 mètre d'une cible murale sur laquelle était repérée 3 angles : 55°, 90° et 125°. Cette cible graduée était centrée sur l'angle de 90°. On pouvait la régler en hauteur afin d'en aligner le centre avec le moignon de l'épaule. A l'aide d'une visée laser fixée au poignet, il était demandé au sujet de mémoriser et de reproduire en abduction puis en flexion les 3 positions (55°,90° et 125°) à 3 reprises pour un total de 18 mesures par épaule et donc 36 mesures par patients. Les mesures étaient effectuées les yeux bandés afin d'éviter toute aide visuelle et l'épaule dénudée afin d'éviter toute stimulation cutanée. Le poignet était bloqué par une orthèse amovible afin de s'affranchir de toute erreur liée à la mobilisation de celui-ci. Pour chaque mesure, il était relevé sur la cible graduée, par un même évaluateur pour chaque patient, l'écart entre l'angle visé et l'angle effectivement réalisé en valeur absolue de degrés. Cet écart était désigné sous le terme de « déviation ». Pour chaque patient, l'âge, le sexe et le membre dominant étaient recueillis. Concernant l'analyse statistique, les variables quantitatives étaient décrites par la moyenne avec écart-type et les variables qualitatives par la proportion. Les différents groupes étaient comparés par un test de Wilcoxon-Mann-Whitney pour les variables quantitatives.

Figure 1 .

 1 Figure 1. Le patient placé à 1m du mur, en face d'une cible, doit reproduire les 3 angles (55°, 90° et 125°) qui y sont notés, en abduction et en flexion

  ), il n'y avait pas de différence significative en fonction des mouvements et amplitudes sauf dans le cas de la flexion à 55° où le membre dominant était significativement plus performant avec une déviation moyenne de 8° contre 9° pour le membre controlatéral (p=0,03). En analyse univariée, seul l'âge était significativement associé à la présence d'une erreur de position (p = 0.003) mais le côté dominant et le sexe ne l'étaient pas (respectivement p = 0.29 et p = 0.59).En abduction (figure4), il y avait une différence significative entre la déviation moyenne à 125° et à 90° comme à 55°. Il n'y avait pas de différence significative entre les déviations moyennes à 55° et à 90° d'amplitude. En flexion, il y avait une différence significative entre les déviations moyennes de chacune des amplitudes.

Figure 2 .Figure 3 .

 23 Figure 2. Déviation moyenne en fonction du sexe, pour les trois positions testées, en abduction et en flexion. Absence de différence significative

Figure 4 .

 4 Figure 4. Déviation moyenne en fonction de la position en abduction et en flexion. Ecart significatif pour la position à 125° dans les deux amplitudes.

  Aydin et al. (16) avançaient que le membre dominant pouvait produire de meilleurs résultats en raison de phénomènes d'apprentissage. En effet, d'une part, le membre dominant est le plus sollicité et, d'autre part, la flexion à 55° est le secteur de mobilité des activités répétées de la vie quotidienne, constituant donc un secteur "surentraîné" et par conséquent plus performant. Néanmoins, dans cette étude la différence significative observée entre les deux membres ne repose que sur un degré d'écart en flexion à 55°. Cette différence n'est pas cliniquement significative et l'évaluation d'un plus grand nombre de patients permettrait de mieux connaître les performances du membre dominant dans ce secteur. La capacité à reproduire une position donnée en flexion diminue avec l'augmentation de l'amplitude du mouvement à reproduire. En abduction, il n'existe pas de différence significative entre les secteurs à 55° et 90° mais on observe une tendance en ce sens. Ces constatations diffèrent des séries existantes (1, 12) où les résultats étaient meilleurs dans le plan de l'épaule (90°). L'explication alors avancée était que plus l'amplitude du mouvement augmentait, plus la tension musculo-tendineuse était importante, provoquant ainsi un recrutement plus important des mécanorécepteurs intra-tendineux, principaux organes proprioceptifs (5). Ici, plus l'amplitude du mouvement était élevée, plus elle était source d'erreurs. La précision était donc moins bonne avec l'augmentation des amplitudes. En ce sens, Lönn et al. (21) ont mis en évidence que la capacité à reproduire une position donnée était meilleure lorsque le membre partait d'une position intermédiaire et réalisait donc un mouvement de moins grande amplitude par rapport à la position de départ. Il faut également prendre en compte la fatigabilité musculaire qui augmente avec l'amplitude. Elle diminue le sens de positionnement articulaire et donc la précision du mouvement (22, 23). Dvir et al. (24) ont souligné l'importance de la notion de significativité clinique lors de la mise en évidence d'une différence statistiquement significative entre deux mesures. En effet, il peut exister une différence statistiquement significative entre deux valeurs mais encore faut-il que cette différence corresponde à un changement clinique significatif chez le patient. En prenant en compte les mesures réalisées dans cette étude, nous proposons de considérer qu'une déviation est cliniquement significative à partir de 15°. Conclusion L'évaluation proprioceptive de l'épaule est complexe tant sur le plan pratique que sur le plan analytique. Le test de Balke est simple et peu coûteux. L'âge est un facteur influençant la SPA, contrairement au sexe ou au caractère dominant du membre. De même, la déviation augmente avec l'amplitude en flexion. D'autres études sur de plus larges effectifs sont nécessaires. Le test de Balke est simple et permettrait le suivi proprioceptif des épaules pathologiques après leur traitement. D'autres études sont également nécessaires afin de mieux connaître les valeurs de déviation attendues chez le sujet sain. Enfin, à l'avenir, il serait intéressant d'évaluer la corrélation entre scores fonctionnels et évaluation de la sensibilité de position articulaire afin de mieux connaître les conséquences fonctionnelles d'un déficit proprioceptif. Conflits d'intérêt :

Figure 1 :

 1 Figure 1 : Le patient placé à 1m du mur, en face d'une cible, doit reproduire les 3 angles (55°, 90° et 125°) qui y sont notés, en abduction et en flexion

Figure 2 :

 2 Figure 2 : Déviation moyenne en fonction du sexe, pour les trois positions testées, en abduction et en flexion. Absence de différence significative

Figure 3 :

 3 Figure 3 : Déviation moyenne en fonction du caractère dominant ou non du membre, pour les trois positions testées, en abduction et en flexion. Différence significative pour l'élévation antérieure à 55° en faveur du membre dominant.

Figure 4 : 2 :

 42 Figure 4 : Déviation moyenne en fonction de la position en abduction et en flexion. La déviation augmente avec l'amplitude en flexion.

  ont montré le lien entre instabilité et SLAP lesion ou lésion de Bankart et donc, plus largement, entre altération des capacités proprioceptives et lésions capsulaires. La proprioception glénohumérale est altérée chez le patient instable chronique et il a été montré que ce déficit est progressivement corrigé après chirurgie stabilisatrice


Morgan Laigle
email: morgan_laigle@hotmail.com

Louis Rony

Raphaël Pinet

Romain Lancigu

Vincent Steiger

Laurent Hubert

Intramedullary nailing for adult open tibial shaft fracture. An 85-case series

Keywords: V, retrospective study Open fracture, tibial shaft, intramedullary nailing, Gustilo classification, infection

Introduction. Treatment of open tibial shaft fracture is controversial due to the risk of infection. We assessed results in a continuous series of open tibial shaft fractures treated by primary intramedullary nailing. Hypothesis. Factors can be determined for non-union and onset of infection following primary intramedullary nailing in open tibial shaft fracture. Patients and method. A retrospective study assessed open tibial shaft fractures treated by primary intramedullary nailing between January 2007 and December 2013.

Fractures were classified on the AO and Gustilo classifications. Infection rates and time to union were compared. Results. Eighty-five patients (85 fractures) were included: 13 Gustilo type I, 43 type II, 19 type III-A and 10 type III-B. Eight patients had infection (9%). Healing and union were obtained after nail exchange and reaming in 5 cases, and after bone transport in 2. One patient showed non-union at last follow-up. Infection risk did not correlate with Gustilo (p = 0.55) or AO type (p = 0.69). The interval between trauma and wound debridement was significantly longer in infected patients (p = 0.048). Eighty-three fractures (97.6%) healed, at a mean 6.9±6.1 months (range, 2-40). Non-union was associated with AO type (p=0.04), and showed a non-significant association with Gustilo type (p = 0.06). Discussion. Time to treatment was the only factor influencing risk of infection. Non-union was related to AO comminution grade. Primary intramedullary nailing seemed reliable if treatment was early, with rigorous debridement. The advantages then are early resumption of weight-bearing and low patient burden.

Introduction

Primary intramedullary nailing in open tibial shaft fracture is controversial due to risk of infection [START_REF] Gustilo | Prevention of infection in the treatment of one thousand and twenty-five open fractures of long bones: retrospective and prospective analyses[END_REF][START_REF] Gustilo | The management of open fractures[END_REF][START_REF] Gaebler | Rates and odds ratios for complications in closed and open tibial fractures treated with unreamed, small diameter tibial nails: a multicenter analysis of 467 cases[END_REF]. The classic attitude consists in primary external fixation, especially in case of severe softtissue lesion and/or hemodynamic instability [START_REF] Roberts | Damage control orthopaedics: evolving concepts in the treatment of patients who have sustained orthopaedic trauma[END_REF]. However, this treatment incurs several problems, with pin infection rates up to 50% [START_REF] Court-Brown | External fixation for type III open tibial fractures[END_REF], non-union rates between 10% (6) and 41% [START_REF] Shannon | Unreamed intramedullary nail versus external fixation in grade III open tibial fractures[END_REF], and malunion rates up to 71% [START_REF] Court-Brown | External fixation for type III open tibial fractures[END_REF]. Intramedullary nailing enables stable fixation, weight-bearing, simple skin coverage and low patient burden. The present study hypothesis was that certain factors affect healing and infection after primary intramedullary nailing for open tibial shaft fracture. The aim of the study was to assess healing and infection rates in a continuous series of primary intramedullary nailing for open tibial shaft fracture.

Patients and method

Patients

A single-center retrospective continuous series included patients operated on between January 2007 and December 2013, with 102 open tibial shaft fractures in 101 patients. Seven fractures were treated by external fixation; 2 of these patients (3 fractures) had multiple trauma and died in the immediate postoperative period; the other 4 fractures received secondary intramedullary nailing. Five fractures were treated by plate fixation, and 92 fractures (92 patients) by primary intramedullary nailing. Seven patients were lost to follow-up before the study minimum of 6 months, without healing at last follow-up, and were excluded from analysis.

Only open tibial shaft fractures treated in emergency by primary intramedullary nailing were included. Exclusion criteria comprised; age <15 years; associated joint fracture; fracture in pathologic (tumor) or infected (osteitis) bone; primary external or plate fixation; and follow-up <6 months.

Data were analyzed for 85 patients: 23 female, 62 male; mean age, 40.3±19 years (range, 15-91 years). On the Gustilo classification (8), 13 fractures were type I, 43 type II, 19 type III-A and 10 type III-B. In 38 cases, there were associated bone and joint lesions. Seven cases showed bone defect. Fracture location was in the superior third of the tibia in 2 cases, midthird in 32, and inferior third in 51. On the AO (Arbeitsgemeinschaft für Osteosynthesefragen) classification AO [START_REF] Müller | The Comprehensive Classification of Fractures of Long Bones[END_REF], fractures were 45 type A, 19 type B and 21 type C.

Surgical technique

The first step consisted in drastic debridement with resection of damaged soft tissue and devascularized bone fragments. Tibial torsion was modeled on the contralateral limb. In 37 cases the nail used was UTN TM , in 26 AO TM and in 22 Expert TM (all Synthes®). Reaming was performed in 41 cases. Nail locking was static in 71 cases.

Dual antibiotic prophylaxis was implemented with amoxicillin + clavulanic acid and gentamicin in 82 cases, and with clindamycin + gentamicin 48h in 3 cases of Gustilo II [START_REF] Patzakis | The role of antibiotics in the management of open fractures[END_REF]. In Gustilo I fractures, mean antibiotic prophylaxis time (amoxicillin + clavulanic acid) was 3±1.5 days (range, 2-7 days) associated to 24h gentamicin. In Gustilo II and III, gentamicin was administered for 48h. Mean amoxicillin + clavulanic acid administration time was 4±2.4 days (range, 2-12 days ) in Gustilo II, 5.2±2.7 days (range, 2-10 days) in III-A and 12.9±4.3 days (range, 8-21 days) in III-B (maintained until skin cover was achieved in III-B).

In 10 cases of Gustilo III-B, closure could not be achieved and an aspiration dressing was implemented [START_REF] Liu | Early soft tissue coverage and negative pressure wound therapy optimises patient outcomes in lower limb trauma[END_REF], with assisted healing in 4 cases, thin skin graft in 3, and emergency flap in 3 (1 soleus at day 1, 1 fasciocutaneous at day 17, 1 dorsalis major at day 7). Three patients (1 Gustilo II, 2 Gustilo III-A) developed secondary skin necrosis requiring a flap (2 soleus at days 21 and 48, 1 fasciocutaneous at day 60).

Assessment

Fractures were classified following Gustilo and the AO. Location on the shaft, any bone defect, and interval from trauma to debridement were noted, as were skin coverage procedures and time after treatment initiation. Clinical and radiographic assessment with full-leg AP and lateral views was performed at 6 weeks, 3 months, 6 months then monthly until healing (if not achieved by 6 months), defined as bone callus uniting at least 3 cortices. Delayed consolidation (non-consolidation at 6 months but callus progression on the following X-ray) or definitive non-union at 6 months and any procedures to promote consolidation (dynamization, change and reaming of nail) were noted. Malunion exceeding 5° frontally and/or sagittally was screened for at the time of consolidation on full-leg AP and lateral views. Onset of sepsis was defined by CRP elevation with hyperleukocytosis and purulent effusion and/or local inflammatory signs and/or positive bacteriology at revision surgery.

Statistics

Correlations between onset of infection or non-union and Gustilo or AO type were analyzed on Fisher exact test. Correlation between onset of infection and time to treatment was analyzed on parametric Student t test. Correlation between consolidation time and Gustilo or AO type was analyzed on nonparametric Kruskal-Wallis test. First-order risk was set at 5%. Discrete variables were reported as mean ± standard deviation (range).

Results

Eight patients (9.4%) developed deep infection, without correlation with Gustilo or AO type (Table 1).

Mean trauma-to-debridement time was 406±283 minutes (range, 85-1,520 min), and exceeded 6 hours in 39 cases.

Septic complications were significantly associated with trauma-to-debridement time (p=0,047): mean 594±398 minutes (range, 250-1,520 min) with versus 387±264 minutes (85-1,200 min) without infection. Six of the 8 patients (75%) had >6 hours' trauma-todebridement time.

At last follow-up, 83 patients (97.6%) showed bone healing, at a mean 6.9±6.1 months (range, 2-40 months). Non-union showed a non-significant trend with respect to extent of soft-tissue involvement (p=0.06) (Table 2). AO type correlated with time to healing (p=0.008) and non-union (p=0.04). At 6 months, 28 patients (32.9%) did not show complete bone healing. Twelve showed delayed consolidation, including 4 after dynamization before 6 months, and 1 after nail change and reaming at 4 months, for infection. Sixteen (18.8%) showed non-union: 12 aseptic, 4 septic (Table 3). One septic non-union of distal tibial fracture was managed by transplantar nailing, and 2 required repeat debridement and bone resection, reaming and nail change and segmental bone transport on a nail with monoplanar external fixation (Figure 1). Nine of the 83 patients with bone healing at last follow-up (10.8%) presented >5° malalignment: 7 <10°, 2 >10°. One patient underwent revision surgery for >20° recurvatum, with supramalleolar osteotomy on malunion in a distal tibial fracture.

Discussion

The present results were comparable to those in the literature regarding deep infection rates after primary intramedullary nailing in open tibial shaft fracture (9.4%, compared to 6.5-12.9%, depending on the series [START_REF] Holbrook | Treatment of open fractures of the tibial shaft: Ender nailing versus external fixation. A randomized, prospective comparison[END_REF][START_REF] Court-Brown | Locked intramedullary nailing of open tibial fractures[END_REF][START_REF] Whittle | Treatment of open fractures of the tibial shaft with the use of interlocking nailing without reaming[END_REF][START_REF] Tornetta | Treatment of grade-IIIb open tibial fractures. A prospective randomised comparison of external fixation and non-reamed locked nailing[END_REF][START_REF] Alberts | Open tibial fractures: faster union after unreamed nailing than external fixation[END_REF], taking all Gustilo types together), and especially for Gustilo III-B fractures (20%, compared to 20-33% (9-14)). These rates are lower than in case of external fixation: 21.4-66.7% [START_REF] Court-Brown | External fixation for type III open tibial fractures[END_REF][START_REF] Tornetta | Treatment of grade-IIIb open tibial fractures. A prospective randomised comparison of external fixation and non-reamed locked nailing[END_REF][START_REF] Alberts | Open tibial fractures: faster union after unreamed nailing than external fixation[END_REF]. The present study involved certain limitations. It was retrospective. Inter-observer assessment of soft-tissue lesions varied, introducing a measurement bias [START_REF] Brumback | Interobserver agreement in the classification of open fractures of the tibia. The results of a survey of two hundred and forty-five orthopaedic surgeons[END_REF]. Soft-tissue lesion severity may have been initially underestimated (3 secondary necroses), with consequent underestimation of fracture severity. No difference in infection rates emerged according to Gustilo type or degree of comminution on the AO classification. Only the interval between trauma and debridement was significantly related to onset of deep infection. Some authors questioned the importance of operating within 6 hours of trauma [START_REF] Mauffrey | Acute management of open fractures: proposal of a new multidisciplinary algorithm[END_REF] but, in the present series, 75% of patients with deep infection had intervals exceeding 6 hours, and it seems to us to be crucial that surgery should be initiated as soon as possible, with optimally rigorous debridement. Other factors, not tested in the present study, may have influenced onset of infection: high or low energy trauma mechanism, degree of initial wound contamination, notably from soil, and obesity or smoking [START_REF] Burrus | Obesity is associated with increased postoperative complications after operative management of tibial shaft fractures[END_REF][START_REF] Schmitz | Effect of smoking on tibial shaft fracture healing[END_REF].

The antibiotic prophylaxis protocol did not follow the guidelines of the French Society of Anesthesia and Intensive Care (SFAR) for open fracture and notably for Gustilo type I (21). However, the association of a beta-lactamase to gentamicin is recommended for severely contaminated wounds and/or >4h treatment delay, and only 2 patients with Gustilo I fracture had less than 4 hours' interval between trauma and treatment (220 and 210 minutes, respectively). Antibiotherapy should be initiated as soon as possible [START_REF] Jaeger | Antibiotics in trauma and orthopedic surgery --a primer of evidence-based recommendations[END_REF], as should skin coverage [START_REF] Sinclair | Primary free-flap cover of open tibial fractures[END_REF]. Flap coverage was usually dependent on the availability of the plastic surgery team, and this may have affected results regarding infectious complications.

Consolidation at last follow-up was good, with a rate of 97.6%. However, there was a high rate of non-union in Gustilo III fractures, equivalent to rates for external fixation [START_REF] Shannon | Unreamed intramedullary nail versus external fixation in grade III open tibial fractures[END_REF]. The number assisted healing procedures was high, at 25. One third of dynamization procedures were performed later than 6 months, and only 4 patients (4.7%), 3 of whom had Gustilo III-A fracture, showed aseptic non-union requiring reaming and nail change for consolidation.

We included cases with severe initial bone defect, which must have had negative impact on results for healing and non-union. However, we believe that intramedullary nailing in such cases facilitates secondary segmental bone transport [START_REF] Ferchaud | Reconstruction des pertes de substance osseuse diaphysaires par une technique de transport osseux segmentaire simplifiée sur clou centromédullaire, à propos de 7 cas[END_REF].

Conclusion

Primary intramedullary nailing in open tibial shaft fracture seems reliable and feasible whatever the severity of skin wound and comminution. It effectively stabilizes the fracture site, facilitates skin coverage procedures and early resumption of weight-bearing, and is less burdensome for the patient than external fixation. In Gustilo type III fracture, this internal fixation technique presupposes emergency management associating early antibiotic prophylaxis, meticulous debridement and rapid skin coverage.

Conflicts of interest

None.

Funding sources: none.

Authors' contribution:

The authors all collaborated to write the article

Figure 1 :

 1 Figure 1: Gustilo type III-B open tibial shaft fracture: bone transport with intramedullary nailing at 6 months. Preoperative radiograph (a). Postoperative radiograph at 2 months (b). Segmental bone transport with intramedullary nailing and monoplanar external fixator at 4 months (c). Complete bone healing at 15 months (d).

Table 1 :

 1 Deep infection rates and p-values

	Factors	Deep infection	p-value *
	Gustilo type
	I	7.7% (1/13)	p=0.55
	II	7% (3/43)
	III-A	10.5% (2/19)
	III-B	20% (2/10)
	AO type
	A	9.7% (4/45)	p=0.69
	B	5.3% (1/19)
	C	14.3% (3/21)
	* Fisher exact test

Table 2 :

 2 Non-union and bone healing time, with p-values

	Factors	Non-union and p-values p*	Bone healing time (months) and p-values
				p**
	Gustilo type
	I	7.7% (1/13)	p=0.06	5.5 ± 2.3 (3-12)	p=0.29
	II	16.3% (5/43)		6 ± 4.8 (2-29)
	III-A	36.8% (7/19)		8.9 ± 9.4 (3-40)
	III-B	40% (3/10)		9.2 ± 6.9 (3-23)
	AO type
	A	11% (5/45)	p=0.04	5.5 ± 3.7 (2-23)	p=0.008
	B	21% (3/19)		8.8 ± 9.6 (3-40)
	C	47.6% (8/21)		9.2 ± 5.6 (3-21)
	*Fisher exact test
	**Kruskal-Wallis test

Table 3 :

 3 Surgical revision (for sepsis and assisted bone healing)