Session 8: YODA Best Papers

Torsdag d. 24. oktober
09:30 - 10:30
Lokale: Vingsal 2
Chairmen: Jakob Klit og Søren Ohrt-Nissen

61. Implant Positioning in Undisplaced Femoral Neck Fractures: association to reoperation and development of a scoring system
Maja Ida Boye Koldaas, Josefine Nadia Pedersen, Frederik Damsgaard Højsager, Henrik Palm, Bjarke Viberg
Department of Orthopaedic Surgery and Traumatology, Hospital Lillebaelt, Kolding, Denmark; Department of Orthopaedic Surgery and Traumatology, Hospital Lillebaelt, Kolding, Denmark; Department of Orthopaedic Surgery and Traumatology, Hospital Lillebaelt, Kolding, Denmark; Department of Orthopaedics, Copenhagen University Hospital Bispebjerg, Copenhagen, Denmark; Department of Orthopaedic Surgery and Traumatology, Hospital Lillebaelt, Kolding, Denmark

Background: Undisplaced femoral neck fractures (FNF) are usually treated with internal fixation (IF), but reoperation frequency is 9-19% after 2 years. A predictor for reoperation may be implant positioning, but it has not been well investigated for undisplaced FNF.
Purpose / Aim of Study: The aim of this study was to assess if implant positioning is associated with risk of reoperation following IF of undisplaced FNF with a posterior tilt < 20° in patients > 65 years.
Materials and Methods: Patients treated in the Region of Southern Denmark during 2009-2013 were retrieved from the Danish Multidisciplinary Hip Fracture Register. The patients’ health records and x-rays were reviewed for; age, sex, implant, Charlson Comorbidity Index, mortality, reoperation, fracture classification and implant positioning. X-ray measurements included; posterior tilt, distance to the femoral calcar and the articular margin of the femoral head, placement within the femoral head and implant angulation. Implant placement was scored according to a pre-existing system for scoring of internal fixation (SIFA). Primary outcome was reoperation (simple IF removal not included) within 2 years.
Findings / Results: 406 patients were included; 75% was female and median (range) age was 82 (65-99) years. 1-year mortality was 25 %. There were 45 (11 %) reoperations. Distance to inferior (OR 2(1.1-4)) and superior calcar (OR 2(1.1-5)), tip-apex distance (OR 2(1.1-4)), placement within the femoral head (Ap-view: OR 3(2-9), lateral-view: OR 3(1.3-5)) and inter-implant angle (OR 3(1.4-8)) were individually associated to risk of reoperation. Distance to posterior calcar and SIFA was not associated to reoperation. Using SIFA as base, a modified SIFA (mSIFA) with 7 items/points was developed by including predefined additional x-ray measures. The mSIFA score of 0-2 and 3-4 points had an increased risk of reoperation (OR 28(9-83) and OR 5(2-12)) compared to a score of 5-7. Among the 206 patients with a score of 5-7, the reoperation frequency was 3 %.
Conclusions: This study identified implant placement as a predictor for increased risk of reoperation in undisplaced FNF and has developed a mSIFA for future clinical use.

62. Systemic Intermittent Hypoxic Therapy Inhibits Allogenic Bone Graft Resorption by Inhibition of Osteoclastogenesis in a Mouse Model
Ari Demirel, Natasja Leth Bergholt, Michael Pedersen, Ming Ding, Bent Winding Deleuran, Casper Bindzus Foldager
, Aarhus University Hospital ; , Aarhus University Hospital ; , Aarhus University Hospital; , Odense University Hospital; , Aarhus University Hospital; , Aarhus University Hospital

Background: Hypoxia is a universal stimulus able to drive proliferation, differentiation, apoptosis and homeostasis of most cell types. The adaptative response to short-term hypoxia (systemic intermittent hypoxic therapy, SIHT) in animals has been linked to resistance to tissue injury.
Purpose / Aim of Study: The aim of the study was to evaluate the effect of SIHT on allogenic bone graft survival and to investigate the proinflammatory response attendant to bone homeostasis.
Materials and Methods: Forty eight C57BL/6 mice (6 to 10 weeks old) received implantation of 10 mg of morselized allogenic bone graft posterior to the lumbar spine. The mice were divided into three groups: (A) control group, (B) SIHT one week preoperative or (C) SIHT one week postoperative, and followed for 1 and 4 weeks postoperative (n=8). SIHT consisted of 30 min of 10% oxygen twice a day in a hypoxic chamber with normoxic recovery between exposures. Microcomputed tomography (microCT) was performed to investigate bone graft volume. Analysis of serum proteins were performed using an Olink mouse exploratory multiplex array. Wilcoxon rank sum test, one-way ANOVA, and Kruskal-Wallis rank test were used for statistical analyses.
Findings / Results: Complete graft resorption was observed in 33- 36% of the animals control groups, none of the animals in the pre-operative SIHT group, and one animal in the postoperative SIHT group. Increased bone graft volume was seen on microCT in the preoperative SIHT group after 1 week compared with controls (P=0.03), while a nonsignificant difference was observed after 4 weeks (P=0.12). SIHT resulted in a significant increase in serum levels of the major osteoclast inhibitor osteoprotegerin (OPG) as well as well as other important osteogenic regulators Tgfbr3, Fstl3, Wisp1, and Vegfd (p<0.01). The inflammatory cytokines and RANKL stimulators IL-6 (p=0.03), IL-17A, IL-17F and IL-23R (all p<0.0001) were all increased after 1 and 4 weeks while P-RANKL expression remained constant.
Conclusions: We conclude that the adaptive response to SIHT preoperative activates numerous osteogenic and immunomodulatory pathways leading to inhibition of allogenic bone graft resorption through inhibition of osteoclastic activity.

64. Is percutaneous needle fasciotomy a safe treatment for Dupuytren contracture? – An observational study on 3,365 treated fingers in 2,280 patients
Laura Houstrup Therkelsen, Simon Toftgaard Skov, Malene Laursen, Jeppe Lange
Elective Surgery Centre, Silkeborg Regional Hospital ; Elective Surgery Centre, Silkeborg Regional Hospital ; Elective Surgery Centre, Silkeborg Regional Hospital ; Department of Orthopaedic Surgery, Horsens Regional Hospital

Background: Dupuytren contracture is a progressive disease that causes flexion contracture of one or more fingers which often lead to disabled hand function. Percutaneous needle fasciotomy (PNF) is a minimal invasive surgical treatment using a fine syringe needle to perforate the Dupuytren cord until the finger can be extended. PNF has gained momentum worldwide in recent years, and the procedure is applied in many countries including Denmark. However, evidence regarding complications associated with PNF is sparse, and many hand surgeons fear the risk of iatrogenic nerve and tendon injuries during the procedure.
Purpose / Aim of Study: The aim of this study was to evaluate the safety of PNF for Dupuytren contracture in the largest cohort reported in the literature.
Materials and Methods: This is a single-center, register-based, observational study on all PNF-treated patients between 2007-2015 at Silkeborg Regional Hospital, Denmark. The study population was identified in the Danish National Patient Registry. Diagnosis codes and procedure codes were used to identify possible severe postoperative complications such as: tendon rupture, nerve damage, infection, amputation and reflex dystrophy for all index treatments. The Danish Drug Statistics Registry was used to identify non- hospital-treated infections. All index treatments and postoperative complications identified were verified by manual review of medical records.
Findings / Results: 2,280 patients received PNF treatment with a total of 3,365 fingers treated. Median follow-up was 7.1 years [interquartile range: 4.9-9.5]. 0.18% (n=4) sustained flexor tendon rupture with three having further treatment. 0.04% (n=1) had digital nerve damage, with no further treatment. 0.04% (n=1) had an infection treated in hospital, while 1.4% (n=32) received antibiotics in the primary sector for an infection, or based on suspicion of an infection, after PNF. None of the infections required surgical intervention. No amputation of the index digit or ipsilateral upper limb reflex dystrophy cases were registered in relation to the procedure.
Conclusions: PNF for Dupuytren contracture is a safe procedure with a low rate of severe postoperative complications, when an appropriate technique is applied.

65. Local concentrations of gentamicin obtained by microdialysis after a controlled application of a GentaColl sponge in a porcine model
Maja Thomassen, Pelle Hanberg, Maiken Stilling, Klaus Petersen, Kjled Søballe, Lasse Krag, Carsten Højskov, Mats Bue
Orthopaedic Research Unit, Aarhus University Hospital; Department of Orthopaedic Surgery, Horsens Regional Hospital; Department of Orthopaedic Surgery, Aarhus University Hospital ; Department of Orthopaedic Surgery, Aarhus University Hospital ; Department of Orthopaedic Surgery, Aarhus University Hospital ; Institute of Clinical Medicine, Aarhus University Hospital; Department of Clinical Biochemistry, Aarhus University Hospital ; Orthopaedic Research Unit, Aarhus University Hospital

Background: Local treatment with gentamicin may be an important tool in the prevention and treatment of surgical site infections in high- risk procedures and patients.
Purpose / Aim of Study: The aim of this study was to evaluate the pharmacokinetic profile of gentamicin in bone and surrounding tissue, released from a controlled application of a GentaColl sponge in a porcine model.
Materials and Methods: In 8 female pigs, a GentaColl sponge of 10x10 cm (1.3 mg gentamicin/cm2) was placed in a cancellous bone cavity in the proximal tibia. Microdialysis was used for sampling of gentamicin concentrations over 48 hours from the cavity with the implanted GentaColl sponge, cancellous bone parallel to the cavity over and under the epiphyseal plate, cortical bone, the intramedullary canal, subcutaneous tissue, and the joint cavity of the knee. Venous blood samples were obtained as reference.
Findings / Results: The main finding was a mean peak drug concentration (95-CI) of gentamicin in the cancellous bone cavity containing the implanted GentaColl sponge of 11,315 (9,049-13,581) μg/ml, persisting above 1000 μg/ml until approximately 40 hours after application. Moreover, the concentrations were low (< 1 μg/ml) in the surrounding tissues as well as in plasma.
Conclusions: The mean peak gentamicin concentration from the cancellous bone cavity after a controlled application of a GentaColl sponge was high and may be adequate for the prevention of biofilm formation. However, high MIC strains and uncontrolled application of the GentaColl sponge may jeopardize this conclusion.