High Flex Designs - a walk in the clouds

High flex TKR has caught the common man’s imagination. And the Orthopaedic surgeon is all set to take advantage. Promises of unimaginable postoperative flexion are easily made. The medical rep gives guarantees to the doctor and the doctor to the patient. The newspapers are flooded with this miracle of modern science and technology.

Is this all true? Or is it a fairy tale we are all weaving?

Mehin et al in a recent Meta-analysis studied high flex versus conventional implants.  They included only randomised clinical trials. They found no improvement in flexion with high flex implants.

Nutton et al also studied this. They did a prospective double-blind randomised controlled trial. They studied 56 patients. They found no difference in flexion.

NgFY et al also could not find better flexion in the high flex group nor could Kim et al.

Murphy et al did a review where they included 9 studies. Again high flex implants failed to show more flexion.

I think we need to be careful with high flex implants. Tall claims are made on shaky foundations.

Don’t get me wrong. We are achieving better postoperative flexion nowadays. But are we giving the prosthetic design too much credit?

It all matters. The preoperative range of motion, the severity and type of disease, the surgical skill (meticulous ligament balancing and proper implant position) and the patients’ compliance with postoperative physiotherapy.

So let’s come down from the clouds and do our part – balance, rotate and align them well. Then the magic of flexion will happen. Happy replacing!!