EOS-based cup navigation: Randomised controlled trial in 78 total hip arthroplasties.

BACKGROUND: Minimising the risk of cup implantation outside the safe zone is among the objectives of navigation during total hip arthroplasty (THA). However, given the technical challenges raised by navigation when the patient is lying on the side, many surgeons still use the freehand technique. We conducted a randomised controlled trial to evaluate the new navigation system NAVEOS in the iliac plane, which is easily identified in the lateral decubitus position, with the objective of determining whether NAVEOS navigation decreased the frequency of cup implantation outside the safe zone compared to freehand cup positioning, without increasing the operative time or the frequency of complications. HYPOTHESIS: NAVEOS navigation decreases the frequency of cup positioning outside the safe zone compared to freehand positioning. MATERIAL AND METHODS: This randomised controlled trial compared cup positioning using NAVEOS navigation versus the freehand technique in patients undergoing primary THA. The safe zone was defined according to Lewinnek as 15±10° of radiological anteversion and 40±10° of radiological inclination. Cup position parameters were measured on computed tomography images obtained 3months after THA. The images were read by two independent observers who were blinded to group assignment. The primary evaluation criterion was cup position within the safe zone. RESULTS: A 1:1 randomisation scheme was used to assign 78 patients (mean age, 68years; age range, 44-91years) to NAVEOS navigation or freehand cup positioning. The two groups were comparable for age, gender distribution, body mass index, and preoperative functional scores. In the NAVEOS group, navigation was discontinued prematurely in 6 patients, because of technical difficulties (n=2) or a marked discrepancy with clinical findings (n=4); however, the intention-to-treat approach was used for the analysis. The proportion of cups in the safe zone was 67% (28/39) in the NAVEOS group and 38% (17/39) in the freehand group (P=0.012). Anteversion was within the 5-25° range for 72% (28/39) cups in the NAVEOS group and 46% (18/39) in the freehand group (P=0.021). Inclination was within the 30-50° range for 95% (37/39) of cups with NAVEOS navigation and 85% (33/39) with freehand positioning (P=0.135). The odds ratio for cup implantation outside the safe zone was significantly lower with NAVEOS compared to freehand positioning (0.54; 95% confidence interval, 0.31-0.91). Mean operative time was 74 (range, 45-115) minutes with NAVEOS navigation and 70 (range, 40-105) minutes with freehand positioning (P=0.382). Complications consisted of 1 case each of anterior dislocation and infection, both in the freehand group. DISCUSSION: Compared to freehand positioning, NAVEOS navigation significantly lowered the risk of cup positioning outside the safe zone, chiefly via improved achievement of the anteversion target. NAVEOS was not associated with increases in operative time or morbidity. LEVEL OF EVIDENCE: II, randomised controlled trial with limited statistical power.

Proximal ulnar fractures in adults: a review of 163 cases.

The aim of this study was to report the epidemiological characteristics and the experience of 5 departments of trauma, in France, in the management of fractures of the proximal ulna. 163 patients with fractures of the proximal ulna with a mean age of 49.9 years (range 16-97) were managed. The most common mode of injury was a motor vehicle collision (48%). 18% sustained associated injuries to the ipsilateral limb. Open fractures were present in 42 patients (25%). A total of 109 patients had a fracture of the olecranon, with the Mayo 2A and B types most frequently seen (66%). The patients were invited for clinical examination at a mean duration of 16 months, retrospectively. Validated patient-oriented assessment scores involving the Mayo Elbow Performance Index (MEPI) and the Broberg and Morrey score were evaluated. All patients had follow-up radiographs. The mean arc of elbow motion was 130° (70-150°). The mean MEPI was 91 (20-100) with good results in 23% and excellent results in 52% of the patients. The mean Broberg and Morrey score was 90 after isolated olecranon fracture, and decreased with the complexity of the lesion. 117 fractures (72%) healed with ulnohumeral congruity. 9 fracture non-unions occurred (6%). Although the fracture of the proximal ulna can be described in several classifications, none of them accommodate it satisfactorily, because of the complexity of the lesion. The coronoid process is the keystone for the stability of the elbow. It forms the anterior buttress with the radial head. Tension band wire fixation is by far the commonest technique of internal fixation used for the treatment of non-comminuted olecranon fractures. Dorsal plate fixation is a useful option by providing improved fixation of complex comminuted fractures and fracture-dislocations. The radiocapitellar joint has to be restored appropriately, preserving the radial head when possible and replacing it with a prosthesis otherwise. The lateral collateral ligament complex is commonly disrupted and usually can be reattached to its origin from the lateral epicondyle. In addition, a brief period of hinged external fixation should be considered.

Acetabular component navigation in lateral decubitus based on EOS imaging: A preliminary study of 13 cases.

INTRODUCTION: Acetabular component navigation classically requires palpation of the bone landmarks defining the anterior pelvic plane (APP) (anterior superior iliac spine [ASIS] and pubis), the recording of which is not very reliable when performed in lateral decubitus. The objectives of the current experimental study were: (1) to assess the clinical feasibility of NAVEOS navigation (based on EOS imaging) in lateral decubitus; and (2) to compare precision versus classical APP-based navigation (NAVAPP). HYPOTHESIS: Iliac plane navigation using EOS is as reliable as APP navigation. PATIENTS AND METHODS: A continuous prospective series of 13 total hip replacements were implanted in lateral decubitus under APP-guided navigation (NAVAPP). Planning used preoperative EOS measurement. The ASIS, pubis and ipsilateral posterior superior iliac spine (PSIS) were located and exported to the navigator. Intra-operatively, NAVEOS landmarks (acetabular center, ASIS and PSIS on the operated side) were palpated. Postoperatively, cup inclination and anteversion with respect to the APP were measured on EOS imaging (SterEOS3D software). The SterEOS3D measurements were compared to those of the performed NAVAPP and simulated NAVEOS navigations. RESULTS: Three patients were excluded for technical reasons. In the remaining 10, inclination on NAVAPP and SterEOS3D differed by a median 4° (range, 0-12°), and on NAVEOS versus SteEOS3D by 5° (range, 2-10°); anteversion on NAVAPP and SterEOS3D differed by a median 4.5° (range, 0-12°), and on NAVEOS versus SteEOS3D by 4° (range, 0-14°). CONCLUSION: Precision was comparable between NAVEOS and classical navigation. NAVEOS simplifies cup navigation in lateral decubitus on initial acquisition. These results require validation on a larger sample.

Acetabular fracture: long-term follow-up and factors associated with secondary implantation of total hip arthroplasty.

HYPOTHESIS: The present study sought to determine long-term outcome in acetabular fracture and the factors associated with secondary implantation of a total hip arthroplasty and/or with poor functional results. MATERIAL AND METHODS: Seventy-two patients admitted between 2000 and 2005 were followed up for a maximum 11 years (mean, 6.8 years): 16 females, 56 males; mean age at injury, 41.6 years (median, 40 years). There were 45 simple acetabular fractures, 27 complex fractures and 27 dislocations. Late complications were: osteoarthritis (n=29), osteonecrosis of the femoral head (ONFH: n=8) and heterotopic ossification (n=2). RESULTS AND DISCUSSION: Twenty-five total hip arthroplasties (THA) were performed, with a mean time to surgery of 3.7 years. Associated factors for THA were: VAS (P<0.0001), PMA (P<0.0001), osteoarthritis (P<0.0001), ONFH (P<0.0002), initial dislocation (P=0.0002), no functional treatment (P=0.0014), surgical treatment (P=0.0065), initial traction (P=0.0068), anterior and posterior congruency defect (P=0.0072 and P<0.0001), and initial intra-articular foreign body (P=0.045). Factors associated with poor or bad functional results were the same, plus: etiology (P=0.0021), BMI (P=0.03) and posterior wall fracture (P=0.0325). LEVEL OF EVIDENCE: 4; retrospective study.

From first base: the sequence of the tip of the X chromosome of Drosophila melanogaster, a comparison of two sequencing strategies.

We present the sequence of a contiguous 2.63 Mb of DNA extending from the tip of the X chromosome of Drosophila melanogaster. Within this sequence, we predict 277 protein coding genes, of which 94 had been sequenced already in the course of studying the biology of their gene products, and examples of 12 different transposable elements. We show that an interval between bands 3A2 and 3C2, believed in the 1970s to show a correlation between the number of bands on the polytene chromosomes and the 20 genes identified by conventional genetics, is predicted to contain 45 genes from its DNA sequence. We have determined the insertion sites of P-elements from 111 mutant lines, about half of which are in a position likely to affect the expression of novel predicted genes, thus representing a resource for subsequent functional genomic analysis. We compare the European Drosophila Genome Project sequence with the corresponding part of the independently assembled and annotated Joint Sequence determined through "shotgun" sequencing. Discounting differences in the distribution of known transposable elements between the strains sequenced in the two projects, we detected three major sequence differences, two of which are probably explained by errors in assembly; the origin of the third major difference is unclear. In addition there are eight sequence gaps within the Joint Sequence. At least six of these eight gaps are likely to be sites of transposable elements; the other two are complex. Of the 275 genes in common to both projects, 60% are identical within 1% of their predicted amino-acid sequence and 31% show minor differences such as in choice of translation initiation or termination codons; the remaining 9% show major differences in interpretation.