REVISED-Final-Program-HKU-Research-Day-2012

Yoga Raja Rampersaud, MD FRCSC Associate Professor, Department of Surgery, University of Toronto Divisions of Orthopedic Surgery and Neurosurgery, University Health Network Medical Dire

DIVISION OF ORTHOPEDIC SURGERY

Dr Yoga Raja Rampersaud, MD FRCSC Associate Professor, Department of Surgery, University of Toronto

Divisions of Orthopedic Surgery and Neurosurgery,

University Health Network Medical Director, Back and Neck Specialty Program, Altum Health

Immediate Past President Canadian Spine Society

We are pleased to welcome Yoga Raja Rampersaud, MD, FRCSC,

as the 2012 H K Uhthoff Visiting Professor

South America-born Dr Rampersaud graduated in 1992 with his honours Medical Degree from the University of Western Ontario (UWO) in London, Ontario and completed Orthopedic specialty training at UWO in 1997 Two fellowships followed – in Orthopedic Spine Surgery at UWO in 1997 and in Neurosurgical Spine Surgery in 1998 at University of Tennessee, Memphis

Currently an Associate Professor in Surgery at University of Toronto, Dr Rampersaud joined University Health Network’s Division of Orthopedic Surgery and Neurosurgery as a consultant in 1999 Dr Rampersaud is the immediate past president of the Canadian Spine Society His academic interests are in minimally invasive spine surgery, surgical safety and outcomes from a health services perspective.

RESIDENT RESEARCH REQUIREMENTS THE DIVISION OF ORTHOPEDIC SURGERY

3 Preliminary results are presented to the Division of Orthopedic Surgery Research

Committee in early April

4 The final paper is presented at the H.K Uhthoff Research Day in April

5 Papers are chosen for submission to Collins Day in May

6 Two completed manuscripts must be written in style of the Journal of Bone and

Joint Surgery and submitted to the Chairman of the Resident Research Committee, one by the end of the PGY-3 year and one by the end of the PGY-4 year

DIVISION OF ORTHOPEDIC SURGERY

2011 - 2012

DIVISION OF ORTHOPEDIC SURGERY RESIDENCY TRAINING COMMITTEE

Tribe Medical Group

Wright Medical (Mr Trevor Fisher)

Dr Joel Werier, Director of the Orthopedic Surgery

Residency Training Program, University of Ottawa

0805 Welcome/Introduction of Dr Rampersaud

Dr Eugene K Wai, Department of Orthopedic Surgery, University of Ottawa

0810 Comparative Effectiveness of the Surgical Management of

Focal Spinal Stenosis Compared to Hip and Knee Osteoarthritis

Dr Yoga Raja Rampersaud, Visiting Professor

0830 Discussion

SESSION I MODERATOR: Dr Wade Gofton

0840 1 Quantitative CT and MRI Changes in Arthritic and

0904 3 A Randomized Controlled Trial of a Cemented vs

Cementless Femoral Component for

Metal-on-Metal Hip Resurfacing: A Bone Mineral Density Study

Dr Andrew Tice, PGY-1

0912 Discussion

0916 4 Stress Distributions in the Hip Before and After

Corrective FAI Surgery

K.C Geoffrey Ng, Graduate Student, Department of

Mechanical Engineering, University

of Ottawa

0924 Discussion

0928 5 Open Reduction and Internal Fixation of Pilon

Fractures: Violating the 7 cm Skin Bridge

Rule

Dr Geoffrey Wilkin, PGY-3

0936 Discussion

0940 6 Vacuum Assisted Closure (V.A.C ) Effects on Skeletal

Muscle After Compartment

Syndrome in an Animal Model

Dr Geoffrey Wilkin, PGY-3

0948 Discussion

Refreshment Break and Exhibits, Royal Room

SESSION II MODERATOR: Dr Karl-André Lalonde

1041 7 Arthroscopic Acetabular Labral Debridement in Patients Aged >45 Years has Minimal

1117 10 Outcome Comparison of Revised Hip Resurfacing with

Primary and Revised Total Hip

Arthroplasties

Dr William Desloges, PGY-4

1125 Discussion

1129 11 Ulnar Placement of the Distal Biceps Tendon During

Repair Improves Supination

Strength: A Biomechanical Analysis

Dr Marc Prud’homme-Foster, PGY-4

1137 Discussion

1141 12 Comparing the Extensor Digitorum Communis

Splitting Approach to the Posterolateral

Kocher Approach: A Novel Method of Measuring Articular Surface Area

Dr William Desloges, PGY-4

1149 Discussion

1153 13 Lesser Tuberosity Osteotomy versus Subscapularis Tendon Peel: Differences in Healing

Rates and Fatty Infiltration

Dr Milton Parai, Clinical Fellow

1201 Discussion

Lunch and Exhibits, Royal Room

SESSION III MODERATOR: Dr J Pollock

1315 In Experimental Surgery Is The Use of the Contralateral Limb for Comparison

Health Services Perspective

Dr Yoga Raja Rampersaud, Visiting Professor

1409 15 Percutaneously Assisted Total Hip (PATH)

Arthroplasty: Learning Curve and Early

Results in a Canadian Centre

Dr Cai Wadden, PGY-3

1500 18 Quantifying Acetabular Overcoverage

Dr Nathan Sacevich, PGY-4

1508 Discussion

1512 19 Tibial Nail Distal Positioning: A Radiographic Study

Dr Travis Marion, PGY-2

1520 Discussion

1524 20 Normal Anatomy of the Distal Radio-Ulnar Joint

Anatomy - A Bayesian Analysis of

1,000 Wrists

Dr Markian Pahuta, PGY-4

1532 Discussion

1536 21 Patella Tendon Insertion Failure: Evaluation of a

Reconstructive Technique

Dr Hani Zamil, Clinical Fellow

1544 Discussion

1548 22 Stimulation of Macrophages by Chromium (III) Ions

Induces an Increase of TRAP

Expression In Vitro

Stephen Baskey, M.A.Sc Student, Department of

Mechanical Engineering, University of

Ottawa

1556 Discussion

1600 23 Level and Upslope Walking After TKA:

Biomechanical Implications for the

1 QUANTITATIVE CT AND MRI CHANGES IN

ARTHRITIC AND PREARTHRITIC

HIPS

Andrew Speirs MASc, Arturo Cardenas-Blanco PhD, Kawan

Rakhra MD, Mark Schweitzer MD,

Paul Beaulé MD, Hanspeter Frei PhD

Background

Arthritic degeneration of articular joints involves complexbiochemical changes in the cartilage tissue and frequently alsoinvolves changes in subchondral bone density, evident assubchondral sclerosis Femoroacetabular impingement (FAI)

results from a morphological deformity of the hip and has beenassociated with osteoarthritis.

Purpose

To examine differences in subchondral bone and cartilage in FAIand control subjects using quantitative CT and T1ρ magneticresonance imaging

Materials and Methods

Prior to surgery, patients undergoing surgical correction of acam-type FAI deformity as well as asymptomatic subjectsunderwent quantitative CT scans including a calibrationphantom Asymptomatic subjects were classified as normalcontrols or asymptomatic with deformity based on the alphaangle Subjects also underwent T1ρ MRI to determineproteoglycan content The contralateral hip of surgical patientswas also analysed Bone mineral density was measured in fourequal wedges of the superior acetabulum to a depth of 10 mmfrom the bone surface The density was normalized by bonedensity in lumbar vertebra L5 to account for general bonedensity variation between subjects T1ρ values were calculated foranalogous regions on oblique sagittal MRI slices Differencesbetween groups were tested using ANOVA and CT and MRIcompared using linear regression

Results

Bone density was significantly higher in all groups compared tocontrols (p<0.05) T1ρ values were higher in asymptomatic andsurgical groups compared to controls (p<0.05) in the anteriorzone indicating proteoglycan depletion However, correlationbetween T1ρ and density was poor

2 CAN THE ALPHA ANGLE ASSESSMENT OF CAM IMPINGEMENT PREDICT

ACETABULAR CARTILAGE DELAMINATION?

Hynes KK, Beaulé P, Parker G

Background

Significant acetabular cartilage damage is commonly present inpatients suffering from femoral acetabular impingement (FAI) Abetter understanding of which patient is at risk of developingsignificant cartilage damage is a critical component inestablishing appropriate treatment guidelines

Questions/Purposes

We set out to investigate the following: 1) does the severity ofthe CAM deformity in FAI as assessed by alpha angle predictsacetabular cartilage damage; 2) what are clinical andradiographic findings in patients with acetabular cartilagedamage

Patients and Methods

167 patients (129 males, 38 females) with a mean age of 38.4years (range: 17.2-59.7) underwent joint preservation surgery forCAM type FAI All data was collected prospectively as per theANCHOR group protocol On the anteroposterior radiograph, thecenter edge angle and Tonnis grade were assessed Usingspecialized lateral radiographs the alpha angle was quantified.Acetabular cartilage damage was assessed intraoperatively viathe Beck Classification

Results

For all cases, the mean alpha angle was 66.2° (range: 41-90°),and the mean centre-edge angle was 33.3° (range 21-52.5).Patients with an alpha angle of greater than 65 (OR: 3.43,95%CI: 1.04-11.33, p=0.043) had an increased odds of having aBeck score of 3 or greater Increased age (OR: 1.04, 95%CI:1.01-1.07, p=0.03) male gender (OR: 2.24, 95%CI: 1.09-4.62,p=0.03) and alpha angle (OR: 1.05, 95%CI: 1.02-1.09, p=0.01)were associated with a Beck score of 3 or greater, while this wasthe opposite for acetabular coverage as assessed by the centre-edge angle (OR: 0.94, 95%CI: 0.89-0.99, p=0.01)

Conclusions

Patients with Cam-type FAI, and alpha angle of >65 degrees

3 A RANDOMIZED CONTROLLED TRIAL OF A CEMENTED VS CEMENTLESS

FEMORAL COMPONENT FOR METAL-ON-METAL HIP RESURFACING:

A BONE MINERAL DENSITY STUDY

A Tice, PE Beaulé, PR Kim , L Dinh

Division of Orthopedic Surgery, Division of Nuclear MedicineUniversity of Ottawa/The Ottawa Hospital: Ottawa, Ontario,

Canada

Purpose

Studies have shown that femoral neck fracture is a main failuremechanism of Metal-on-Metal (MOM) hip resurfacing, and ithas been established that increased osteopenia of the femoralneck puts the hip at risk of fracture For these reasons, this studywas designed to quantify bone mineral density (BMD) of thefemoral neck when comparing cemented versus cementlessfemoral components for MOM hip resurfacing

Methods

This is a prospective, randomized controlled trial in progress

120 patients were recruited to either a cemented (Conserve Plus)

or cementless (Cormet 2000) prosthesis BMD was measured in

6 femoral neck zones at baseline, 6 months, 1 year and pending 2years The primary outcome was percent change in BMD, andsecondary outcomes were patient functional scores, as well ascomplications/revisions

Results

The cementless group showed greater BMD in 4 zones ascompared to the cemented group at the 6 month period Thisdifference persisted as the cementless group continued to havegreater BMD in 3 zones at 1 year There were no significantdifferences in functional outcome gains between groups Thecemented group had 3 revisions and 4 complications, while thecementless group had no revisions, and 3 complications

Conclusions

The cementless group showed increased BMD at both the 6month and 1 year follow up periods Though it can behypothesized this greater BMD would decrease the risk offemoral neck fracture, and, therefore, implant failure, furtherresearch is needed to determine the impact of increased BMD onlong-term implant survivorship

4 STRESS DISTRIBUTIONS IN THE HIP BEFORE AND AFTER CORRECTIVE

FAI SURGERY

K.C Geoffrey Ng, MASc1* | Mario Lamontagne, PhD21 |Michel

R Labrosse, PhD1 | Paul E Beaulé, MD FRCSC34

1 Department of Mechanical Engineering, University of Ottawa

2 School of Human Kinetics, University of Ottawa

3 Department of Surgery, University of Ottawa

4 Division of Orthopedic Surgery, The Ottawa Hospital

* Hans K Uhthoff Graduate Fellowship Award Recipient

Characterized by an enlarged and aspherical femoral head, camtype femoroacetabular impingement (FAI)has been postulated toimpose elevated stresses at the articulating surfaces, leading to

an eventual failure of the hip joint The purpose of this study was

to examine whether surgical intervention can minimize thestresses in the hip, by comparing the stress distributions beforeand after corrective surgery using finite element analysis

Subject-specific models were segmented from a male patient’spre-operative and post-operative CT data; then simulated duringtwo quasi-static positions from standing to squatting.Peakmechanical stresses were found at the anterosuperior labrum,acetabular cartilage, and underlying bone during the squattingposition.However, stresses were lower for the post-operativemodel on the labrum and acetabulum, in comparison with thepre-operative model (Table 1)

Squatting oriented the cam deformity into the anterosuperioracetabulum, thus increasing impingement with the lateralregions.With the resection of the deformity in the postoperativemodel,more clearance was permitted between the labrum and thefemoral head-neck junction; therefore,minimizing stresses at theanterosuperior labrum and acetabulum as well as reducingcontrecoup levering and stresses at the posteroinferioracetabulum.These findings support the pathomechanisms of camFAI and suggest that, in efforts to preserve the hip joint, there

could be long-term improvementsafter corrective surgeryto the

labrum and underlying bone

Table 1: Peak maximum-shear stresses on the pre-operative

and post-operative models (MPa)

Model Stand Pre-operative Squat Stand Post-operative Squat

Acknowledgement

The authors wish to thank the funding contributions from the

Hans K Uhthoff Graduate Fellowship Award

5 OPEN REDUCTION AND INTERNAL FIXATION OF

PILON FRACTURES:

VIOLATING THE 7 CM SKIN BRIDGE

Geoffrey Wilkin, MD, Wade Gofton, MD, MEd, FRCSC

Steve Papp, MD, MSc, FRCSC, Allan Liew, MD, FRCSC

Division of Orthopedic SurgeryUniversity of Ottawa/The Ottawa Hospital: Ottawa, Ontario,

Canada

Objective

Assess soft-tissue complications and functional outcomes in

patients with pilon fractures treated with open reduction and

internal fixation (ORIF) through multiple incisions less than 7

Thirty-two patients with thirty-six fractures treated between 2000and 2007 were identified from the databases of three orthopedictraumatologists Eighteen patients with twenty fracturesattended clinical follow-up.

Intervention

Incisions were placed so that the length of the vertical overlapnever exceeded the horizontal distance between incisions

Main Outcome Measurements

Soft-tissue complications, range of motion, and functionalscores

Results

There were 9 OTA type B and 27 type C fractures; 8 were openfractures The median number of incisions was 3 ± 1.1, verticaloverlap between incisions was 4.5 ± 1.7 cm, and smallest skinbridge was 5.0 ± 1.8 cm, with 72% of the skin bridges less than 7

cm There were two superficial infections and one deepinfection No cases required a secondary soft tissue coverageprocedure Range of motion was 5 ± 6.8º dorsiflexion and 40 ±11.4º plantarflexion The AMA lower extremity impairmentscore, SIP ambulation score, and SF-36v2 revealed someresidual functional deficits

Conclusions

Our technique of maintaining a vertical overlap less than the skinbridge width had a low complication rate Incisions made lessthan 7 cm apart did not result in a high complication rate.Prudent surgical timing and meticulous soft-tissue handling canallow incisions to be placed as necessary for fracture reductionand optimal fixation while minimizing complications andfunctional impairment

6 VACUUM ASSISTED CLOSURE (V.A.C TM )

EFFECTS ON SKELETAL MUSCLE

AFTER COMPARTMENT SYNDROME IN AN

ANIMAL MODEL

Geoffrey Wilkin1, Shiemaa Khogali2, Shawn Garbedian, Brad

Slagel, Wade Gofton1,Allan Liew1, Jean-Marc Renaud2, Steve Papp1

1Division of Orthopedic Surgery, University of Ottawa

2Department of Cellular and Molecular Medicine, University of

Ottawa

Purpose

A Vacuum Assisted Closure (V.A.C.TM) device can improvewound closure after fasciotomy for compartment syndrome,however, the effects on the underlying muscle are unknown.Our purpose was to evaluate V.A.C.TM effects on skeletal muscleafter fasciotomy for compartment syndrome in an animal model,and to determine if any regional variability in healing responseoccurs within the muscle based on the distance from theV.A.C.TM We hypothesized that V.A.C.TM treatment improvesmuscle fiber regeneration and that this effect is greatest in areasclosest to the V.A.C.TM

Methods

Compartment syndrome was induced in the hindlimb of 20young adult female pigs Fasciotomy was performed after sixhours and the animals were randomized to receive either wet-to-dry gauze dressings or V.A.C.TM dressings for 7 days, followed

by delayed primary wound closure The peroneus tertius washarvested for analysis 1 week or 3 weeks after fasciotomy

Results

After 1 week, V.A.C.TM treated muscles had greater overallweights, and after 3 weeks, had fewer normal fibers and greaterareas containing only mononucleated cells with no fibers Thedifferences in fiber distribution were greatest in areas distantfrom the

V.A.C.TM sponge

Conclusion

In this animal model, and at the treatment settings tested,V.A.C.TM therapy impairs muscle fiber healing after fasciotomyfor compartment syndrome This effect was most pronounced inareas distant from the V.A.C.TM dressing These results must beconsidered in light of the potential wound healing benefits ofV.A.C.TM therapy in human applications

7 ARTHROSCOPIC ACETABULAR LABRAL

DEBRIDEMENT IN PATIENTS

AGED >45 YEARS HAS MINIMAL CLINICAL BENEFIT

Geoffrey Wilkin1, Gerard March, Paul E Beaulé1

1Division of Orthopedic Surgery, University of Ottawa

Purpose

The practice of hip arthroscopy is increasing and labral tears are

a common indication Previous reports have suggested advancedage may be associated with poor outcomes after arthroscopicdebridement Our purpose was to quantify the post-operativefunctional outcomes in older patients (age >45y) Wehypothesized that this group would derive minimal clinicalbenefit and would have a higher re-operation rate than youngerpatients

Methods

Forty (40) patients age >45 years who had arthroscopic labral

debridement were included Prospectively collected pre- andpost-operative WOMAC, SF-12, and Harris Hip Scores (HHS)were retrospectively analyzed Post-hoc univariate logisticregression analysis was performed to identify factors associatedwith a positive clinical response

a bimodal distribution in the magnitude of clinical response.Age was positively associated with improvements in WOMACStiffness score, and pre-operative HHS was negatively

associated with improvement in post-operative HHS

Conclusions

Arthroscopic labral debridement in patients aged >45 years isassociated with a high re-operation rate and minimal overallfunctional improvement However, some patients do derivebenefit The factors associated with positive clinical responseare unclear Arthroscopic debridement of labral tears in thispatient population must be approached with caution as theclinical benefit is unpredictable

8 THE OTTAWA EXPERIENCE USING A MODULAR NECK SYSTEM FOR

PRIMARY TOTAL HIP ARTHROPLASTY

Illical E, Beaulé P, Feibel R, Thurston P, Kim P, Gofton W

Introduction

Modular neck systems for total hip arthoplasty offer the ability toalter femoral version, offset, and leg length independently fromthe femoral stem that has been inserted However, concerns havebeen raised about neck fracture as well as corrosion at themodular head-neck interface The purpose of this study was todescribe the experience of using a modular neck system at ourinstitution and to report any potential complications

Methods

Between January 2006 and June 2011, 580 primary total hiparthroplasties were performed at our center using either a flattapered wedge geometry femoral stem or rectangular taperedstem with a titanium modular neck option (Profemur TL and Z)

by five different surgeons with 3 surgical approaches: posterior,anterior, or lateral Implant details were recorded in a database atthe time of surgery and the patients are being prospectivelyfollowed for any complications associated with the modularfemoral neck

A neutral neck was used in only 18.6% of cases (106/580) Themost common neck used was the varus/valgus accounting for56.9% of cases (330/580) The anteverted/retroverted optionsaccounted for 12.9% of cases (77/580) Theanteverted/retroverted and varus/valgus option accounting for11.2% of cases (65/580) Ninety two percent (533/580) of necksimplanted were short with 57% (302/533) being female Only8% (47/580) of necks were long with 66% (31/47) being males.There were no complications associated with the modularfemoral neck at the latest follow up for all patients

Conclusion

A significant number of patients benefitted from the modularnecks in optimizing their biomechanical reconstruction Unlikeprevious reports, at mid-term follow-up there were nocomplications associated with the modular femoral neck in ourseries with only 8% of patients requiring the long neck options.Further long term follow-up is required to determine if otherfailure modes will occur

9 RADIOGRAPHIC OUTCOMES OF CLOSED

DIAPHYSEAL FEMUR FRACTURES

TREATED WITH THE SIGN NAIL

Carsen S; Park S; Simon D;Feibel RJ

Purpose

The burden of orthopedic trauma in the developing world is verysignificant in both health and economic terms The SurgicalImplant Generation Network (SIGN) provides universal femoral/tibial intramedullary nails and instruments on a donated basis tosurgeons in resource-limited settings Replacement nails areprovided once pre-operative and post-operative radiographs areuploaded to the SIGN database for critique by SIGN surgeon-educators Despite the clinical success of the SIGN Nail, withmore than 50,000 surgeries performed, there has been very littleresearch examining outcomes The primary purpose of thisstudy was to examine the post-operative radiographs of closeddiaphyseal femur fractures treated with the SIGN Nail to assess