Matthieu Ehlinger

Distal femur fractures. Surgical techniques and a review of the literature.

Fractures of the distal femur are rare and severe. The estimated frequency is 0.4% with an epidemiology that varies: there is a classic bimodal distribution, with a frequency peak for men in their 30s and a peak for elderly women; however, at present it is found predominantly in women and in the elderly with more than 50% of patients who are over 65. The most common mechanism is an indirect trauma on a bent knee, and more rarely direct trauma by crushing. The anatomy of the distal femur explains the three major types of fracture. Because of the anatomy of the distal femur, only surgical treatment is indicated to stabilize the fracture. A non-surgical treatment is a rare option. The aim of this report was to provide an update on the existing surgical solutions for the management of these fractures and describe details of the surgical technique applicable to these injuries. Recent radiological, clinical and biomechanical data published in the literature are reported to compare different surgical options.

Septic Arthritis: Monitoring with USPIO-enhanced Macrophage MR Imaging

PURPOSE To prospectively evaluate in vivo noninvasive monitoring of antibiotic therapy in experimental infectious arthritis by imaging macrophages by using magnetic resonance (MR) imaging enhanced with ultrasmall superparamagnetic iron oxide (USPIO) particles. MATERIALS AND METHODS The institutional review committee on animal care approved the experimental protocol. Unilateral knee infection was induced by intra-articular injection of Staphylococcus aureus in 12 rabbits. Each rabbit underwent MR imaging before and after injection of USPIO particles, as well as before and after injection of gadoterate meglumine. All 12 of the animals were imaged during the acute phase of infection. Half were then sacrificed to obtain histopathologic samples, and the other half were imaged a second time after antibiotic treatment. MR imaging data were analyzed and compared with bacteriologic and histopathologic findings. RESULTS In acute infections, intense synovitis with marked signal intensity increase of the synovium on gadoterate dimeglumine-enhanced fat-suppressed T1-weighted images was observed in all animals and was associated with areas of signal intensity loss within the infected synovium on USPIO-enhanced T2*-weighted gradient-echo images, reflecting an intense infiltration of USPIO-loaded macrophages. After antibiotic treatment and histologic evidence of healing infection, less synovial signal intensity loss was seen (P = .03). In contradistinction, the signal intensity increase on gadoterate dimeglumine-enhanced fat-suppressed T1-weighted images remained unchanged. CONCLUSION In contrast to conventional MR imaging performed by using extracellular contrast agents, USPIO-enhanced macrophage MR imaging can demonstrate resolution of experimental bacterial joint infection.

Traitement des fractures fémorales sur matériel par voie mini-invasive et remise en charge immédiate : apport des plaques à vis bloquées (LCP). Série préliminaire

PURPOSE OF THE STUDY We report a consecutive prospective series of femoral fractures on previous implants. The purpose was to assess treatment with locking compression plates and total weight-bearing. MATERIAL AND METHOD From June 2002 to December 2005, we treated 21 patients (16 women, five men) for fractures on previous implants: total hip arthroplasty (n=11), total knee arthroplasty (n=1), unicompartmental prosthesis (n=1), gamma nail (n=4), hip screw (n=1). Mean patient age was 75.8 years (range 39-90). Osteosynthesis was performed on an orthopedic table or on a standard table using a minimally-invasive approach for fixation with a locking compression plate (Synthes) LCP) to bridge the implants in place and avoid any zone of weakness. The rehabilitation protocol included immediate total weight bearing. RESULTS At last follow-up there were three deaths and one failure so that there were 17 patients with a mean follow-up of 15.9 months (range 6-45 months). The following outcomes were noted. Minimally-invasive surgery was used in 18 cases, access to the fracture focus in three. Total weight bearing was possible immediately after surgery in 12 patients and partial weight bearing (20 kg) for two. There were two infections, two general complications and one early displacement. Healing was achieved at 6-10 weeks. Misalignment greater than 10 degrees was noted in three cases. DISCUSSION This work illustrates the use of locking plates for minimally-invasive repair of fractures on previous implants with total weight bearing. This technique combines the principles of closed fixation and preservation of the fracture hematoma with material stability. In this form, use developed progressively. It is now common practice to use plate fixation for femoral fractures. The LISS system was then developed progressively for minimally-invasive repair of distal fractures. We widened the concept to include more proximal approaches. The use of the locking screws in the plate corresponds to what could be called an internal external fixator with three pins (two corresponding to the cortical screws plus the plate), which enable a solid fixation. Screw hold seems to be sufficient to allow early weight bearing. CONCLUSION Locking plates have been shown to be an effective treatment for femoral fractures on previous implants allowing a stable fixation sufficient for early weight bearing.

Periprosthetic femoral fractures treated by locked plating: Feasibility assessment of the mini-invasive surgical option. A prospective series of 36 fractures

INTRODUCTION The treatment of periprosthetic femoral fractures by conventional plating is associated with problems related to fracture union and eventual refracture. Additionally, locking nailing cannot be used in all cases because of the risk of malunion. To resolve these issues, locking plates have been proposed to combine the advantages of closed reduction and internal fixation while achieving a higher quality reduction with plate fixation. HYPOTHESIS Locking plates put into place by a mini-invasive surgical approach result in fixation without substantial misalignment or non-union. PATIENTS AND METHODS From June 2002 to December 2007 we prospectively treated 35 patients (one bilateral), 28 women and seven men with a fracture around the hip implant (21), around the knee (8), between the hip implant and the knee (2), between a trochanteric internal fixation device and the knee implant (5). The mean age was 76, (39-93). Internal fixation was always attempted by mini-invasive surgery using locking plate system with locking screws (Synthès™). Rehabilitation included immediate weight bearing with as much weight as the patient would tolerate. The preoperative Parker score was 5.25 (0-9). RESULTS There was one patient lost to follow-up, one early failure, and seven deaths (four of whom were included in the study group since their follow-up was at least 24 months) for a total of 31 fractures (30 patients), the mean follow-up for the series was 26 months (6-67). Twenty-six fixations were performed by mini-invasive approach and 10 through a conventional open surgery. Patients applied full weight (n=20), partial weight (n=3) or no weight for 6 weeks (n=13). Infections developed in two patients and there were three cases of mechanical failure. Fracture union was achieved in 35 out of 36 cases. More than 5° of misalignment was observed in five patients. Loosening of the implant did not occur in any patients during follow-up. The Parker score in patients seen at follow up was 4.3 (0-9). DISCUSSION-CONCLUSION Locking compression plates associated with a mini-invasive surgical approach result in a high rate of union (35/36) with no significant misalignment (only 5/36 cases of misalignment of more than 5°), no refractures (n=0) and a low rate of mechanical failure (3/36) while allowing full weight bearing in most cases (20/36). Locking plates for periprosthetic femoral fractures allow patients to begin walking again, with stable intermediate term results.

Treatment of distal humerus fractures with LCP DHP™ locking plates in patients older than 65 years.

INTRODUCTION Fractures of the distal humerus are often complex and therefore challenging to treat. In elderly patients with decreased bone strength due to osteoporosis, strong fixation is crucial to allow resuming early motion that guarantees a good functional outcome as well as minimising mechanical complications. Locked implants meet these requirements. Here, we report outcomes in a uniform series of patients older than 65 years with distal humerus fractures managed with LCP DHP(®) (Synthès) fixation. Our objective was to evaluate the efficacy and limitations of this technique. HYPOTHESIS LCP DHP provides strong fixation of osteoporotic bone and leads to good clinical and radiological outcomes. MATERIALS AND METHODS We retrospectively studied 46 consecutive patients (2004-2010) with a mean age of 80 years including 15 with extra-articular and 31 with articular distal humerus fractures. At presentation, 11 complications were noted in nine patients (compound fractures and trauma-related nerve injuries). The transolecranon approach was used in 31 patients. Mean duration of immobilisation was 2.7 weeks in 33 patients. RESULTS Forty-three patients were re-evaluated after a mean follow-up of 25 months (range, 10-64 months); two patients died and one was lost to follow-up. Flexion was 127° and loss of extension was 23°, producing an average range of motion of 104°. Functional recovery was highly satisfactory with a Mayo Clinic Performance Score of 87 (70-100) and 95% of good and very good results. Postoperative complications consisted of infection (n=3), metaphyseal non-union (n=2), ulnar nerve injury (n=6), transient radial nerve palsy (n=1), and peri-articular ossification (n=4). Compound fracture and worse AO fracture type were associated with worse functional outcomes. DISCUSSION Despite the high complication rate, functional recovery was similar to that reported in previous case series, including after arthroplasty. Furthermore, the rate of mechanical complications was lower. Thus, our working hypothesis was confirmed. LEVEL OF EVIDENCE Level IV retrospective non-comparative study.

Le rameau transverse de la branche dorsale du nerf ulnaire : anatomie et rapports avec les voies arthroscopiques du poignet: Quarante-cinq dissections

PURPOSE OF THE STUDY We conducted an anatomic study of the transverse branch of the dorsal ulnar nerve to describe its morphology and position in relation to arthroscopic exploration portals. MATERIAL AND METHODS Forty-five non-side-matched anatomic specimens of unknown age and gender were preserved in formol. The dorsal branch of the ulnar nerve was identified and dissected proximally to distally in order to reveal the different terminal branches. The morphometric analysis included measurement of the length and diameter of the transverse branch and measurement of wrist width. We also measured the smallest distance between the transverse branch and the ulnar styloid process, and between the branch and usual arthroscopic portals (4-5, 6R, 6U) in the axis of the forearm. RESULTS The transverse branch was inconstant. It was found in 12 of the 45 dissection specimens (27%). In two-thirds of the specimens, the branch ran over less than 50% of the wrist width, tangentially to the radiocarpal joint. Mean nerve diameter was 1 mm. It was found 5-6 mm from the ulnar styloid process and was distal to it in 83% of the specimens. The dissections demonstrated two anatomic variants. Type A corresponded to a branch running distally to the ulnar styloid process, parallel to the joint line (10/12 specimens). Type B exhibited a trajectory proximal to the ulnar styloid process, crossing the ulnar head (2/12 specimens). The relations with the arthroscopic portals (4-5, 6R, 6U) showed that the mean distance from the branch to the portal was 3.75 mm for the 4-5 portal (distally in 11/12 specimens), 3.68 mm for the 6R portal (distally in 10/12 specimens), and 4.83 mm for the 6U portal (distally in 7 specimens and proximally in 5). DISCUSSION To our knowledge, there has been only one report specifically devoted to this transverse branch. Two other reports simply mention its existence. According to the literature, the transverse branch of the dorsal ulnar nerve occurs in 60-80% of the cases. We found two anatomic variations different than those described in the literature. Based on our findings and data reported previously, we propose a new classification, describing two main types. In Type 1, the transverse branch arises proximally to the ulnar styloid process;type 1A and type IB are described in relation to the direction of the branch. In Type II, the branch arises distally to the ulnar styloid process;type IIA and type IIB again being described in relation to the direction of the branch. On the tangential trajectory over the radiocarpal joint, the morphometric data show a zone of risk described by a rectangle measuring 10 mm wide (6 mm distal and 4 mm proximal to the ulnar styloid process) and covering 50% of the wrist width. The relations with arthroscopic portals describe a zone of risk corresponding to a 5-7 mm radius circle centered on the portals (4-5, 6R, 6U), which includes 83% of the transverse branches.Resume Le but de ce travail etait de definir l’anatomie morphologique du rameau transverse de la branche dorsale du nerf ulnaire, et de definir ses rapports avec les voies d’abord arthroscopiques du poignet (4-5, 6R et 6U), a partir 45 dissections de pieces anatomiques. Le rameau transverse est variable dans son existence oscillant entre 80 % des cas selon la litterature et 27 % pour notre etude (12 fois sur 45). Selon notre etude, il presente un diametre moyen de 1 mm et un trajet tangentiel a l’articulation radio-carpienne. Deux fois sur 3, il parcourt moins de 50 % de la largeur du poignet. Dans 83 % des cas, il est situe a 5-6 mm en distalite du processus styloide ulnaire. Il existe ainsi une zone a risque schematisee par un rectangle de largeur de 10 mm sur 50 % de la largeur du poignet, centre sur le processus styloide ulnaire, en regard de l’interligne articulaire radio-carpien. Deux types de variations anatomiques, differentes de celles deja publiees, ont ete observees. Le rameau transverse est situe a proximite des voies d’abord arthroscopiques 4-5, 6R et 6U. Les resultats de notre etude anatomique soulignent l’existence d’une zone a risque schematisee par un cercle centre sur chaque voie d’abord, de 5 a 7 mm de rayon incluant 83 % des rameaux transverses. Afin d’eviter une complication nerveuse, il faut avoir a l’esprit l’anatomie de la branche dorsale du nerf ulnaire, l’existence de ces zones a risques et une parfaite connaissance des voies d’abord. Ce respect des structures nerveuses est d’autant plus important que cette region anatomique de la face dorsale du poignet peut etre utilisee comme lambeau pedicule pour la chirurgie reconstructrice.

Distal locking of femoral nails: evaluation of a new radiation-independent targeting system.

Objectives: The purpose of this study was to assess the effectiveness of a novel radiation-independent aiming device for distal locking of intramedullary nails in a human cadaver model. Methods: A new targeting system was used in 25 intact human cadaver femora for the distal locking procedure after insertion of an intramedullary nail. The number of successful screw placements and the time needed for this locking procedure were recorded. The accuracy of the aiming process was evaluated by computed tomography. Results: The duration of the distal locking process was 8.0 ± 1.8 minutes (mean ± SD; range, 4–11 minutes). None of the screw placements required fluoroscopic guidance. Computed tomography revealed high accuracy of the locking process. The incidence angle (&agr;) of the locking screws through the distal locking holes of the nail was 86.8° ± 5.0° (mean ± SD; range, 80°–96°). Targeting failed in 1 static locking screw because of a material defect in the drilling sleeve. Conclusions: This cadaver study indicated that an aiming arm–based targeting device is highly reliable and accurate. The promising results suggest that it will help to decrease radiation exposure compared with the traditional “free-hand technique.”

Critical analysis of olecranon fracture management by pre-contoured locking plates

BACKGROUND Fractures of the proximal ulna are rare and usually managed surgically. Strong fixation of the harware is essential to obtain good outcomes. We report our experience with pre-contoured locking plate fixation of complex olecranon fractures and present a critical appraisal of the outcomes. HYPOTHESIS Pre-contoured locking plates provide good outcomes, but their clinical tolerance may be limited in some instances. MATERIALS AND METHODS From September 2009 to December 2011, 28 patients were managed using a pre-contoured locking compression plate (LCP(®)). Among them, 6 were excluded because of missing data, which left 22 patients (11 males and 11 females) with a mean age of 55.7 years, including 12 who were employed. The fracture was on the dominant side in 11 patients. According to the Mayo Clinic classification, 15 fractures were type II and 7 type III. In addition to the ulnar fracture, a radial head fracture was present in 9 patients and a coronoid process fracture in 5 patients. Functional recovery was assessed using the Broberg-Morrey score and Mayo Elbow Performance Score (MEPS). Radiographs were obtained to evaluate the quality of fracture reduction and fracture healing, as well as to look for ossifications and osteoarthritis. RESULTS Mean follow-up was 20 months. Flexion was 131°, extension loss was 9.5°, pronation was 79°, and supination was 80.5°. The mean Broberg-Morrey score was 96.7 and the mean MEPS score 96.6. Fracture healing occurred in all patients, within a mean of 10.6 weeks. Evidence of early osteoarthritis was found in 6 patients, ossifications in 3 patients, and synostosis in 1 patient. An infection was successfully treated with lavage and antibiotic therapy in 1 patient. The fixation hardware was removed in 6 patients. No prognostic factors were identified. DISCUSSION-CONCLUSION Our hypothesis was confirmed. The outcomes are encouraging and comparable to those reported in the literature. The critical issue is the limited clinical tolerance of the plate with a high rate of posterior impingement requiring plate removal (27%). Rigorous technique is essential during plate implantation. LEVEL OF EVIDENCE Level IV, retrospective study.

Advantage and limitations of a minimally-invasive approach and early weight bearing in the treatment of tibial shaft fractures with locking plates

OBJECTIVES Intramedullary nailing is a common method of treating tibial shaft fractures. However, precise control of reduction at the proximal and distal quarters is difficult to achieve. The purpose of this study was to assess the results of plating using locking screws and the feasibility of a minimally-invasive approach. PATIENTS/PARTICIPANTS All patients with tibial shaft fracture treated by means of locking plates from January 2004 to October 2006. Thirty-two fractures were treated in 32 patients with a mean age of 43.8 years. INTERVENTION Internal fixation with a locking plate and screw construct, using a minimally-invasive or standard approach. MAIN OUTCOME MEASUREMENTS Surgical approach, time to weight bearing, complications and their type, time to bone union, alignment in the frontal and sagittal planes on anteroposterior and lateral radiographs. RESULTS The minimally-invasive approach was performed in 28 cases and immediate full weight bearing allowed in 25 cases. At a mean follow-up of 27 months, two patients had died and two patients were lost to follow-up. The mean time to bone union was 9.1 weeks. Four cases had a complicated course: one infection, one compartment syndrome, one hardware breakage and one pseudarthrosis. Six cases ended up with valgus malunion exceeding 5° in the frontal plane, already present at the time of surgery. CONCLUSION Where a minimally-invasive approach can be performed, immediate pain-free weight bearing can be allowed without further displacement at follow-up. The observed rate of malunion underlines the need for adequate reduction and shows that the rationale for success does not solely depend on the plate anatomic design but also on the skills of the operating surgeon. SETTING Level I university regional hospital Cohort study.

Un nouvel implant pour les fractures de l’humérus proximal : la plaque à corbeille: Étude expérimentale

Resume Nous avons realise une etude comparative de trois systemes d’osteosynthese des fractures de l’humerus proximal dont les conclusions ont permis l’elaboration d’un implant d’osteosynthese rigide extra-medullaire. Cet implant tire son originalite de la fixation specifique des tuberosites par un systeme de griffes organisees en corbeille. Il existe sous deux versions, avec et sans verrouillage de la vis centrale cephalique. Le travail que nous rapportons est l’etude de ce prototype par deux tests mecaniques statiques sur pieces cadaveriques congelees, sur la base d’un modele experimental de fracture a quatre fragments de l’humerus proximal. Les premiers tests ont ete realises en compression axiale permettant d’analyser le comportement mecanique global de l’implant et d’evaluer l’interet du systeme de verrouillage de la vis centrale cephalique. La seconde serie de tests a ete realisee en traction, permettant l’analyse du comportement des tuberosites fixees par le systeme de griffes. Les deux versions de prototypes ont ete comparees a un implant connu. Nous avons evalue les montages par leur tolerance mecanique jugee sur la charge limite notee a l’inflexion de la courbe, et leur rigidite jugee sur la pente de la courbe jusqu’a cette valeur. Il resultait de la premiere etude que l’implant, ameliore du systeme de verrouillage de la vis centrale cephalique, presentait de meilleures caracteristiques mecaniques globales sans pour autant qu’une difference significative ait ete mise en evidence. La notion de meilleure tenue des tuberosites par le systeme de griffes, que laissait presager la premiere partie, etait renforcee par les donnees de l’observation de la seconde etude, sans qu’il apparaisse pour autant de difference statistiquement significative.PURPOSE OF THE STUDY We conducted a comparative study of three ostheosynthesis systems for proximal humeral fractures. The conclusions led to the elaboration of a rigid extramedullary osteosynthesis implant. This novel implant allows specific fixation of the tuberosities via six adjustable and removable hooks organized like a basket. There are two versions, with and without a central cephalic locking screw. We report two static biomechanical studies conducted to analyze this material. MATERIAL AND METHODS The two studies were performed on fresh frozen cadaver specimens with known bone density and with an experimental model of a four-fragment fracture of the proximal humerus. The first tests were designed to measure axial pressure reproducing the physiological movement applying the most stress on the head of the humerus. This allowed a global analysis of the mechanical behavior of the implant and an assessment of the contribution of the central cephalic locking screw. The second series of tests were traction tests used to analyze the behavior of the tuberosities fixed with the hooks. We assess the assemblies by measuring the mechanical resistance: rigidity of the fixation was recorded in mm/100N. Pre- and post-procedure x-rays and photographs were obtained to allow a subjective assessment of fragment displacement. RESULTS The first series of tests demonstrated that the implant, with the central cephalic locking screw, presented good overall mechanical properties. The notion of better stability of the tuberosities obtained with the hooks, as seen during the first tests, was reinforced by the data from the second tests, although no statistically significant difference was demonstrated. We also noted that there was no statistically significant correlation between bone density and the slopes of the force-resistance curves. DISCUSSION This prototype implant has an overall mechanical resistance equivalent to the reference implant, with at least equivalent performance. Proof of the usefulness of the central locking screw was not established, even though improved tolerance to loading by better force distribution seemed apparent. The contribution of the hook basket was not demonstrated. Data from the observations do however suggest the expectations of the implant will be fulfilled. Tests conducted on a larger scale would probably demonstrate a difference. It is clear that the small number of implants used here limited the study. Comparison with data in the literature show that this new prototype is adapted to the mechanics of the proximal humerus. Resistant to physiological stress, the implant allows pendular movement and passive physical therapy during the early post-operative period.