• Thermal Shrinkage for the Treatment of ACL Injuries

    Simon Roberts is a Consultant Orthopaedic and Sports Injury Surgeon. Mr Roberts’ caseload consists entirely of sports injuries and trauma, although he doesn’t do routine joint replacement surgery. The majority of his work is minimally invasive surgery of the knee, shoulder and ankle for problems of joint instability, ligament and cartilage problems and joint surface defects. Mr Roberts treats elite & professional sportsmen in football, rugby league and rugby union. The Oswestry orthopaedic team has provided treatment for players from most of the Premiership football and Super League rugby teams over the last decade.

    In some Anterior Cruciate Ligament (ACL) injuries, the ligament is not totally ruptured, but is referred to as being stretched”. Could you explain the pathology of a stretched ACL and how it might affect a patient?

    “A slack as opposed to totally ruptured ACL can be as a result of 3 kinds of injury. Firstly, the ligament may be truly stretched out, but not completely torn. Secondly, it may have ruptured completely, but managed to heal in a slackened position. This occurs most frequently with a low energy “peel-off” of the top end of the cruciate from the femur (thigh bone) which then sticks itself back onto an adjacent structure which leaves it slack. Thirdly, part of the ligament may be completely ruptured, but part of it intact.

    “Depending on the degree of laxity and also on a number of other factors including the patient’s level of activity and neuromuscular control (strength and balance) this may lead to instability episodes. ACL incompetence is not an all or nothing phenomenon. Some people will have symptomatically very unstable knees even with activities of daily living, whereas others will be able to play sport to a very high level with no or next to no trouble.”

    Is a stretched ACL more likely to become a ruptured ACL if the person is active in sports?

    “This is not known. Increasingly surgeons are realising that it is the instability that is the problem in the knee and not the lax ligament. If a patient has functional control of the joint either by excellent rehabilitation or occasionally by modifying their activities, then it is unlikely that further damage will occur. If the knee is symptomatically loose, however, it is very likely that they will run into further trouble in the short to medium term.

    Would ACL reconstruction surgery be appropriate for a stretched ACL?

    “Again we are treating patients and not ligaments. If the ACL is a little slack, but the patient has absolutely no symptoms as a result of it, then it would be quite wrong to suggest removing the ligament and replacing it with a graft. On the other hand, if the ACL is stretched to the extent where problems are occurring in the knee then most surgeons would recommend reconstruction.”

    Can you explain how the thermal shrinkage technique works for stretched ACLs?

    “We have been using the thermal shrinkage technique for nearly 10 years now in Oswestry and have looked carefully at our results. The technique of thermal modification of collagen (the tissue that ligaments are comprised of) has been around for a long time. Initially, lasers were used to tighten up the capsule in the shoulder, but more recently specifically designed radiofrequency probes have been used which are much cheaper and safer.

    “Essentially as collagen is heated up to around 67 degrees it will typically shorten by up to 30% and this can be observed and fine-tuned at operation. The procedure is done as a day case and takes only a few minutes. Patients go home the same day and are allowed to bear full weight through the knee.”

    What is the typical rehabilitation period before returning to sports following thermal shrinkage for a lax ACL?

    “Our routine rehabilitation protocol is on my website under the links/rehabilitation tab. Our senior physiotherapist, Andrea Bailey, has been working on this, but we have been happy with it over the last 3-4 years. Essentially, it is out towards 3 months before return to full-on contact sport, with more or less a full range of movement in about the second week. We tend to avoid open kinetic chain quadriceps strengthening exercises for 2-3 months and it is important to avoid re-injury during this period as the thermally modified collagen is rather vulnerable to being stretched out before it is fully mature.”

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