In 2003 our team at the Cincinatti Sportsmedicine Research and Education Foundation undertook research to study the outcome of meniscal repair in young active patients in whom removal of meniscal tissue would likely result in a major loss of function and future joint breakdown [see original publication].

Particularly we wanted to evaluate the results of removing meniscal tissue from the central region of the meniscus where blood supply is virtually absent despite the meniscus still functioning to protect the joint.

About 20 years ago torn menisci were frequently removed in their entirety, but it is now well recognised that menisci have an important role to play in -

  • load sharing
  • joint surface (cartilage) protection
  • joint stabilization

X-rays and other imaging techniques have been used to demonstrate the insidious progression of joint surface destruction after meniscectomy.

From the perspective of healing, the meniscus can be divided into three areas. The outer one-third has good blood supply and is called the 'vascular' or 'red' zone. Blood supply diminishes as one progresses towards the flattened inner aspect - and this inner two thirds is called the 'avascular' or 'white' zone.

Knee surgeons refer to the junctions between these zones, where tears frequently occur, as -

  • red-on-red
  • red-on-white
  • white-on-white

according to the vascularity of the edges of the tear.

Research has shown that tears in the outer red zone heal well but tears in the inner part of the white zone do not usually heal. But there is limited research data about tears of the outer part of the white zone, ie the area >4mm from the meniscal pheriphery.

 

Our study

We determined to evaluate the results of meniscal repair in this central zone in a group of patients under 20 years of age - assessing all patients both before and after surgery.

We also particularly wanted to evaluate the results where meniscal repair was combined with ACL reconstruction. This particular age group is important as meniscectomy in people so young condemns them to almost certain later knee problems.

Sixty-one consecutive patients under 20 were included in the study. The mean age was 16 (range 9-19). 88% had reached skeletal maturity. In total we operated on 74 menisci (more than one in some patients), but three patients were lost to follow-up, so the results we present are of 71 menisci.

Of the 71, in 14 the ACL was intact. Of the remainder, in 43 the ACL was repaired at the same time. In the remaining 14, the ACL was repaired later for various reasons.

We allowed immediate knee motion and encouraged early muscle strengthening. Full weight-bearing was only allowed after six weeks. No squatting, running, jumping or twisting was allowed for six months.

 

Limitations of the study

Because this study was carried out over a 14 year period, and surgical knowledge advanced over this time, the earlier ACL procedures were done with allograft (cadaver tissue) while the later ones were done with autograft (own tissue). However, the procedure was the same ('bone-patellar tendon-bone') and the operations were done by the same surgeon.

A problem we found was the difficulty of objectively assessing the long term integrity of the meniscus without incurring additional expense for the patients for MRI and/or follow-up arthroscopy. So we had to go largely on clinical findings, and we only proceeded to MRI and/or follow-up arthroscopy where it was clinically warranted.

 

What did we find?

Seventy-five percent (53 menisci) had no symptoms at follow-up. Of the 18 menisci (25%) in which the meniscal repair failed, 14 had symptoms suggestive of failure (usually pain), but 4 had no pain. That is, the sensitivity of pain in predicting failure was low.

However, where there was pain failure was virtually always present, ie the specificity of pain as a predictor of failure was high.

ACL reconstruction at the same time did not prejudice the meniscal repair. In fact these patients did rather better, probably because they were specifically instructed not to put the knee at further risk.

Importance of Surgical Technique

Meniscal tears heal primarily by migration of cells from the edge of the meniscal rim. We stress to our colleagues the importance of meticulous technique in bringing the two surfaces of the torn meniscus into close opposition. We abrade the wound edges and use multiple non-absorbable sutures (stitches) every 4-5 mm. Vertical sutures are stronger. We fill the gap with fibrin clot if there is any loss of tissue at the repair site, and sometimes use a 'micropick' in the notch near the ACL to induce some local bleeding. We do not use fixation devices (eg arrows) to hold the edges together as we find it hard to get a meticulous closure.

Recommendations

With 75% having no symptoms at follow-up, we feel that it is very worthwhile to attempt repair in these young patients.

 

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