October 2009
Q: When did you first start in Orthopaedics?
A: My orthopaedic training was basedaround Oswestry and I also spent 2 years in Sydney training in sports medicine. My trauma instruction in Stoke on Trent. I was appointed consultant at Robert Jones and Agnes Hunt Orthopaedic Hospital Oswestry and Wrexham Maelor Hospital in 1992.
Q: What do you think in general about Minimal Invasive Surgery (MIS) for hips?
A: I’d been sceptical initially because of problems with the 2 incision and Rottinger approaches. Also with cemented implants, a high quality cement technique is difficult to achieve through less invasive methods. However I have used cementless implants with hard metal /metal bearings since 1992 using a lateral Bauer approach but encountered occasional limping, trochanteric pain and the surgery causes significant blood loss. I was consequently keen to explore MIS techniques. The anterior approach appears the only truly muscle sparing technique but before the AMIS table, required at least 2 assistants with long surgical time. Using The AMIS table attachment I only require one assistant, the surgery is entirely predictable and the surgical time is similar to standard approaches.
Q: Which MIS techniques did you do first?
A: I tried both the Rottinger and posterior minimally invasive techniques. The former is a modified Watson-Jones with the patient in the lateral position but the surgery remains challenging even after a long learning curve and published complications are high. In particular errors in cup position can easily occur and femoral fracture is not uncommon in the reported results. The small posterior approach seems attractive at first but does not offer significant advantages to the patient apart from cosmetic.
Q: Why did you first start with AMIS?
A: I commenced my training in AMIS approximately 9 months ago and have undertaken 71 cases plus 10 hemiarthroplasties for neck fracture. Despite the high learning curve, I have not encountered any significant complications in terms of implant position. Leg length determination is easy with patient supine and if image intensification is used. The operating time is now approximately 50-70 minutes with reduced blood loss and very predictable short term results. An added benefit is because of the supine position in combination with the AMIS table, intra-operative use of intermittent calf compression is possible with the benefits of DVT prophylaxis. I have already welcomed visiting surgeons to demonstrate the technique and will soon travel to other institutions as part of the Medacta AMIS training regime.
Q: Do you operate all patients with AMIS?
A: Since I started this technique I have not used any other approach for primary replacement and have treated patients of all shapes and sizes, all ages and pathologies. Severe dysplasia would be a relative contraindication. Osteoporotic fracture patients have done particularly well with this method.
Q: Cemented stems are often preferred in the more elderly patient and achieve excellent results. Is it possible to use cemented products whilst using the AMIS approach?
A: We are currently developing in the UK a cement technique with specialised plug introducers and curved cement nozzles which will soon be available. The instruments for MIS cemented cups already are available and I have used this technique on occasion.
Q: What do your patients’ think of AMIS?
A: The short answer is: Fantastic. They experience minimal pain with many able to lift the leg or bend the knee in recovery. Many go home after 2 days. Post operatively I do not restrict them in terms of sleeping position, sitting on low chairs, bending etc. as dislocation is so rare, which they clearly appreciate and they need minimal OT input which is a cost benefit. Those having AMIS who have undergone conventional surgery lateral or posterior particularly emphasise a great difference. Finally, limp is eliminated.
Q: What do you expect from AMIS in the long term, say, 10 years post-op?
A: The measured advantages are of course short term but already there are MRI studies demonstrating superior muscle recovery in AMIS when compared with conventional techniques. Also, future revision surgery should be more straightforward as muscles have not been damaged and tissue planes intact.