Projects
Knee Replacements
- Tibial baseplate trial
- A prospective randomised controlled trial comparing three tibial base plates in total knee arthroplasty (TKA).
- Coolican, M.R.J., Parker, D.A., Graham, D.
- There are many available varieties of implants and methods of fixation of the tibial
(lower) component of total knee replacement. The implants are fixed to the bone
either by using cement, screws or uncemented “ingrowth” techniques. This third type
of implant is coated with materials which cause bony ingrowth and result in solid
fixation, while initial fixation relies on “pressfit” interference between the implant
and the bone.
All of these forms of implants have been commercially available and in regular use
for over a decade. Our aim is to compare these three. There is sparse literature directly
comparing the short and long term outcomes of these implants in a prospective randomised
study. Our hypothesis is that uncemented tibial implants have a longer survival outcome
than cemented ones when performed by a single surgeon.
Patient recruitment commenced in 2005 and approximately 130 patients have been recruited by mid 2009.
- TKA analgesia study
- An examination of the efficacy of femoral nerve blocks versus local
anaesthetic wound infiltration only and the effect of Gabapentin
- Pattullo, G., Parker, D.A., Coolican, M.R.J.
- Post surgical analgesia is needed to cover the pain caused from disruption to multiple
tissue types whilst at the same time allow active rehabilitation of a normally very mobile
joint. Many different analgesia techniques have been used to meet these often competing
demands, each having unique risks and benefits.
Femoral nerve blocks are used commonly during TKA as well as local anaesthetic infiltration
to the wound at the end of the procedure. Increasingly, Gabapentin is being used as a co-analgesic
in the acute pain setting. The use of Gabapentin has been studied in many postsurgical pain
settings in which its use has been shown to reduce opioid consumption.
We aim to conduct a double tiered controlled, randomised double blind study of FNB and Gabapentin
following TKA to increase knowledge regarding the analgesia which provides the best outcome for patients.
Arthritis
- High tibial osteotomy (HTO) studies
- Detailed analyses of high tibial and distal femoral osteotomy assessing
clinical outcomes, gait, and MRI of articular cartilage regeneration / degeneration.
- High tibial osteotomy is a well established operation for osteoarthritis. Often patients have
arthritis localised to one side of their joint and an alignment of the legs that places the
majority of their weight in this area. In this case, correcting the alignment to place the body
weight towards the other side of the joint will usually relieve symptoms as well as slow the
progression of the arthritis. The damaged articular cartilage is thought to then have some
potential also to repair or regenerate.
- MRI analysis of cartilage volume pre- and post-osteotomy
- Parker, D.A., Giuffre, B., March, L., Vanwanseele, B.
- The volume of cartilage regeneration and the content of the regenerated cartilage structure
after high tibial osteotomy (glycoaminoglycan content) is being analysed. Participants undergo an
MRI after a gadolinium injection to enhance contrast of the images. It is believed that
“regenerated” cartilage is not of original quality which has major implications for both the
patient and the Health System in terms of pain relief, delaying total joint arthroplasty and
also cost.
- Analysis of gait pre-and post-osteotomy
- Parker, D.A., March, L., Vanwanseele, B.
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- Osteoarthritis and the consequent pain can result in changes to the way patients walk as a result
of malalignment or the attempt to minimise this pain. The analysis of gait allows us to examine
scientifically the extent of the deviation of gait from normal and any improvements which occur
after a high tibial osteotomy.
- Analysis of osteotomy outcomes with and without cartilage cell implantation
- Parker, D.A., Coolican, M.R.J., Giuffre, B.
- Another option available to surgeons for patient treatment is to combine the osteotomy procedure
with another well established technique of articular cartilage transplantation (MACI) to restore the
joint surface in the arthritic side of the knee joint.
The purpose of this study is to compare the clinical, MRI and gait results of patients who have a high
tibial osteotomy alone, with those who have an high tibial osteotomy combined with MACI, to determine
whether or not addition of this technique enhances the regeneration and repair of damaged cartilage
in knee joints with arthritis. This will have significant implications for our ability to treat
arthritis and return arthritic joints back to normal function.
- Safety Study of the iBalance Axial Knee Realignment System
- Parker, D.A.
- Sydney Orthopaedic Research Institute is one of the worldwide sites for a study assessing
the safety and effectiveness of performing a high tibial osteotomy with a new surgical procedure
and new implant devices. This study is being conducted to help physicians understand and improve
the quality of care for patients who are being treated for malalignment of the knee.
The iBalance® Axial Knee Realignment (AKR) TM System introduces an instrument-guided surgical
technique. The newly developed implant is comprised of a biomaterial called PEEK which has
mechanical properties more similar to bone than metallic plates and screws. In addition, the
implant fits flush with the bone surface, thereby creating a more aesthetic appearance.
Sports Injuries
- SORI Sign PCL Study
- A prospective study looking at the accuracy of a specific physical finding
in distinguishing between acute and chronic PCL injuries.
- Coolican, M., Parker, D., Hanson, C., Kinzel, V.
- Injury to the posterior cruciate ligament of the knee is a commonly encountered sports injury
that is generally associated with a direct anterior to posterior blow to the tibia or a
hyperextension mechanism. Occasionally, these athletes will have sustained previous injuries to
their knees, making it difficult to determine whether an injury to the posterior cruciate ligament,
detected on physical exam, is acute or chronic. The purpose of the current study is to test the
predictive accuracy of a physical exam finding, proposed as the “SORI Sign”, in the determination
of acute versus chronic PCL injury.
This study commenced in mid 2009.
- Anterior cruciate ligament (ACL) fixation trial
- A randomised trial comparing two methods of tibial fixation in anterior
cruciate ligament reconstruction surgery.
- Parker, D.A., Coolican, M.R.J.
- Surgery is an effective method of restoring stability to a knee that has had an ACL injury.
A graft, commonly hamstring tendon, is used to reconstruct the injured ligament. There are several
different methods of fixing the graft to the femur (thigh bone) and tibia (shin bone). This study
is comparing two available techniques of tibial fixation, RCI screw with staple fixation, and the
Intrafix screw.
Patients were randomised for fixation type at the time of surgery. The patients are being assessed
for knee stability and function for two years following surgery. Results of the ACL Fixation Study
will provide both patients and surgeons with information regarding ACL reconstructions, and help
direct future treatment plans.
Recruitment of patients began in 2005 and a total of 114 patients are included in the study.
- Patellar dislocation study
- A prospective analysis of the epidemiology and outcomes of acute patellar
dislocation.
- Parker, D.A., Coolican, M.R.J., Duggal, N.
- Dislocation of the patella may occur during childhood but is more frequently seen in adolescence.
It may occur due to a trauma and often occurs in knees with a pre-existing patellofemoral problem.
Clinical evaluation after patellar dislocation/relocation usually reveals a swollen knee that is
difficult to examine and x-rays after this injury are often normal. However MRI studies have shown
associated injuries to structures in the knee.
We are examining the mechanism of injury and MRI findings as well as any resulting surgical
management. A better understanding of the mechanism of injury and the associated MRI injury
patterns will assist in the future management of these injuries as well as assist in
determining if there are any factors which predispose to recurrence of dislocation.
Currently we have studied 90 patients, and will continue to collect information on future
outcomes or recurrent injuries.
- Multiligament Injury study
- Analysis of Injury Mechanism, Associated Injuries and Outcomes of
Multiligament Injuries of the Knee
- Knee dislocation is an uncommon, but serious injury. This study assessed the mechanism of
injury, and the associated damage to ligaments, bone, cartilage and blood supply. Retrospective
review of patients with multi-ligament knee injuries was performed. Inclusion criteria were
either a confirmed knee dislocation, or complete rupture of two or more ligaments. Outcomes
following operative and nonoperative management were reviewed. Clinical assessments, including
validated outcome scores, were performed in the majority of patients.
Student Projects
- Intraoperative Measurements and TKA Outcomes
- Conrad, L., Parker, D.
- Total knee arthroplasty is a routine procedure for treatment of severe knee degeneration
or destruction from diverse causes. A relatively recent change to the procedure involves
computer assisted surgical guidance for accurate placement of the surgical prosthesis.
- This study examines both objective and subjective endpoints in patients who have undergone
total knee arthroplasty utilizing intraoperative component navigation. Intraoperative data
was collected as raw figures from the navigation and alignment process of the surgery. Outcome
data was also collected for the same group of patients one year post surgery via questionnaire
and clinical measurements. This data was analysed to determine whether a correlation exists
between intraoperative computer assisted surgical data and one year outcomes of patients who
had undergone elective total knee arthroplasty.
- This project was taken on by Len Conrad, a second year Graduate Medicine student at University
of Sydney, in March 2009. It is currently on-going.
- Early vs. Delayed ACL Reconstruction Surgery
- Houang, J., Parker, D., Coolican, M.
- Reconstructive surgery of the anterior cruciate ligament has become an increasingly common
procedure, the main candidates being young athletic individuals. Injury to the ACL may result
in either a partial tear of the ligament or a complete rupture. The premises for reconstructive
surgery vary with the patient’s activity level, the degree of the injury and levels of instability.
As with the decision to have surgery, the timing of the procedure varies with the degree of injury
and other patient factors. Many studies have been conducted regarding the optimum time for ACL
reconstructive surgery, however a general consensus is yet unclear. This study aims to contribute
to this existing body of knowledge and collate sufficient data to be able to suggest a general
time frame for surgical intervention that results in the best outcomes for patients.
- Jessica Houang, a second year Biomedical Engineering student at University of Sydney took up this
project in April 2009 as part of her work experience at SORI.
- Insertion Site Position in Single Bundle ACL Reconstruction
- An FEA modelling project investigating the effect of insertion site position
for single bundle ACL reconstruction on the isometry of the ACL and resultant biomechanics of the
knee joint.
- Sundaramurthy, R., Parker, D.
- One of the more difficult decisions made during ACL reconstruction is on how to place the tibial
and femoral tunnels for the ACL graft so that it has the longest life and mimics the function of the
natural ACL. The longest life of the ACL graft is achieved by placing it in a position to achieve
isometry. But achieving isometry does not mean that the graft will mimic the function of the natural
ACL. Placing the ACL graft in the anatomical footprint of the natural ACL will mimic the normal knee
function better than isometric graft placement. But this comes at a cost of graft longevity.
- The aim of this study is to find out how changing the position of the tibial and femoral tunnel
will affect the degree of isometry of the ACL graft and how this affects the ROM of the knee using
finite element analysis. This study can potentially predict an optimal position for the placement of
the graft to maximise the longevity and mimic the function of the normal knee more closely.
- This study is being undertaken as a thesis project by Ravi, a final year Biomedical Engineering
student at the University of Sydney.
- An Investigation into the Causative and Associated Factors of Osteonecrosis of the Knee- a discussion
aimed at clarifying variations between idiopathic and secondary types.
- Leon, V., Parker, D., Mufti, J.
- Osteonecrosis of the knee is a well described clinical syndrome that affects a significant portion
of the elderly community and can result in marked morbidity and loss of function.
- Classically, osteonecrosis has been subdivided into idiopathic and secondary types depending on
whether the pathological changes observed can be attributed to a known causative factor. If no such
factor can be identified, the condition is said to be idiopathic. More recently, much research has been
aimed at determining the mechanism that underlies these bone changes. This study aims to gather information
regarding lifestyle factors from patients presenting with clinical features consistent with osteonecrosis
in an attempt to find an aetiological correlation and contribute to the body of research within the field.
In this way, the concept and mechanism of osteonecrosis will become more clearly defined.
- Viktoria Leon, a second year Medical Student at University of Sydney, took up this project in May 2009
as an Honours Project with SORI.