Q1. Is the suture placed inside or outside of the joint capsule?
A. Outside. The joint capsule is typically opened to examinine the meniscus. It is, however, easier to separate the joint capsule from the tensor facia lata before incising the joint capsule. Identify the fabella and then open the joint capsule.
Q2. How much tension does the suture require?
A. There is almost no research data on this. We advise the tension should be sufficient to eliminate the anterior draw but not enough to create an outward rotation. Excessive tension is as great a technical error as insufficient tension.
Q3. Why has the suture broken?
A. If the suture is restraining the movement of the tibia under the femur the suture will always break. The timescale is usually 6-8 weeks. Rupture of the suture at this time does not affect theoutcome. If the suture remains unbroken at 12 weeks it is not functional and may be removed without affecting the outcome of the procedure. The suture will break at the point of maximum abrasion. 60% break at the fabella.
Q4. I think the suture is infected?
A. If you think there is a problem, intially try antibiotics, preferably after bacteriology and sensitivity. If at 8 weeks the problem is unresolved, remove the suture, take swabs and see what happens. 90% of sutures removed, suspected of infection are, in fact, sterile.
Q5. Where does the suture pass?
A. Although the proximal tibia and the fabella are not ideal isometric points, their convenience as suture points dictates that they are used as anchor points. The fabella is relatively mobile and until severe osteoarthritis ensues can be used as an anchor point. It is useful to dissect out the fabella in a cadaver specimen to identify the fibrous structures which will hold a lateral suture. Once passed the nylon should be secure enough to lift the dog from the table. If the suture pulls through then the suture is in the wrong place. Try to avoid including soft tissues within the loop as these will cheese wire through and cause laxity within the loop. The tibial suture should be placed as cranial and as proximal as possible. A common error is to place the hole too far distally which will limit the extension of the stifle.
Q6. Where should the crimp sit?
A. It should sit distally over the Cranialis Tibialis muscle. Avoid leaving it pressing on bone.
Q7. My nylon broke close to the crimp?
A. Take care not to crimp too close to the end of the crimp. Leave around 1mm of crimp uncrimped. If the crimper gets too close to the end of the tube, the edge can increase abrasion and failure.
The photograph shows a correct crimp on the left. The center crimp may well slip. The right hand pictures shows the crimps too close to the end of the tube.
Q8. My nylon has pulled out of the crimp?
A. Insufficient crimp. Using the original crimper you must squeeze as hard as possible to grip the nylon. If this seems like hard work, try our new compound action crimper which being double jointed exerts more pressure per given squeeze than the original simple action crimper.
Q9. My question is not covered by any of the above?
A.Click this link to send an e-mail to John Lapish who will respond directly.