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.C., 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 75 patients have been recruited by late 2006.

Unicompartmental knee arthroplasty (UKA) trial

A randomised trial comparing two unicompartmental knee arthroplasty systems.

Parker, D.A., Coolican, M.R.J.C., Duggal, N.

Unicompartmental knee replacements are effective in treating pain which is secondary to medial knee osteoarthritis. There are several systems currently used for this type of surgery and this study aims to compare two well established systems. This is a prospective, randomised clinical study of the Accuris versus the Oxford Knee Systems. The study will compare improvement in pain, function and quality of life, and the durability of each implant.

The study commenced mid 2004 with approximately 60 patients recruited by late 2006.

Range of motion (ROM) following total knee arthroplasty (TKA)

An analysis of progression of ROM following TKA – assessing importance of rate of gain in range of motion on eventual range achieved.

Coolican, M.R.J.C., Parker, D.A., Graham, D.

Following total knee replacement, patients are seen daily by hospital staff to assess ROM as well as to assist with activities of daily living. Many orthopaedic surgeons will discharge their patients from hospital only once they have attained 90° of knee flexion.

Our study aims to assess the importance of immediate post-operative ROM (at the time of discharge) and final ROM and functional outcome at one year following surgery.

This study commenced patient recruitment in early 2004 and approximately 100 patients were enrolled by late 2006.

Local anaesthetic reinfusion during TKA

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.C.

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.

Time of surgery study

Comparison in outcomes between patients operated first thing in the morning and patients operated on last thing in the evening.

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.P., Guiffre, 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.P., March, L., Vanwanseele, B.

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.P., Coolican, M.R.J.C., Guiffre, 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.P.

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

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.C.

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.C., 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 73 patients, and will continue to collect information on future outcomes or recurrent injuries.

ACL bone bruise study

Osteochondral injuries following Anterior Cruciate Ligament Rupture

An ongoing investigation looking at the injury mechanisms, osteochondral and other intraarticular injuries, and outcomes associated with ACL rupture. We have examined 100 patients following ACL rupture, collecting information about how their injury occurred. We also analysed the damage to knee cartilage and underlying bone structures (bone bruising) as seen by MRI. This has enabled us to describe the different injuries patterns displayed with differing mechanisms of injury. In the future we would like to see whether different injury mechanisms may alter the progression of osteoarthritis in these patients.

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.

Posterior cruciate ligament study

Gait Analysis in PCL Injured Patients – in collaboration with Sydney University

Most PCL ruptures are managed conservatively and do not require surgical reconstruction. Patients generally return to sport at the same level as prior to injury. The aim of the study was to investigate any adaptations in muscle activity that would compensate for knee instability in these patients. We have studied the lower limb biomechanics in patients as they start to run. 8 patients with PCL ruptures have been compared to 8 normal controls. Strength testing was also used to compare injured and normal legs.

Basic Science Projects

Horizontal cleavage tears in menisci study

External fixator study

External fixators are instruments which are attached to the bone using bone pins and are used to provide stability to knees with considerable ligament injuries, such as those which occur during road accidents. The aim of these fixators is to offer stability while also allowing movement at the joint. This study aims to examine the effect of the application of one fixator on the knee ligaments. The four major knee ligaments (anterior cruciate ligament, posterior cruciate ligament, medial collateral ligament, lateral collateral ligament) are being instrumented with strain gauges in six cadaveric lower limbs. The limbs are then moved at a uniform angular velocity through flexion and extension. Ligament strain is recorded as well as the moment/torque required to effect the movement.

Other Projects

dGEMRIT MRI of tendon

Gown Study

MRI surgical decision