Thermal Capsular Shrinkage

What is it?

Capsular Shrinkage is an Arthroscopic surgical procedure where the loose ligaments and capsule of the joint are (physiologically) tightened using a special radiofrequency heating probe.

VAPR Radiofrequency Probe

Who is it for?

• It is indicated for people with very loose shoulder joints causing problems of dislocations or subluxations, where there has been no major trauma to cause the 'looseness'. This is known as  a Loose Shoulder or Multidirectional Instability (MDI). 

• It is not suitable for people who have had a major injury causing the dislocation and have no capsular looseness. These patients require a repair of the torn structures (Bankart repair) (see Shoulder Instability).

• Occasionally throwing, overhead athletes also develop looseness of the shoulder due too repetitive straining of the ligaments and capsule. These athletes may also benefit from a capsular shrinkage procedure.

Multidirectional Instability

A person is said to have multidirectional instability (MDI) when the humeral head can be moved abnormally far in the glenoid cavity in more than one direction. This condition is due to having an excessively loose capsule. In a small number of cases, MDI is part of an inherited syndrome involving unusually loose ligaments throughout the body. Collagen is the major protein of the shoulder ligaments and capsule. Tissue analysis has demonstrated a significantly smaller average diameter of the collagen fibre in samples of patients with atraumatic MDI compared to another group with traumatic anterior instability. This suggests the possibility of an underlying collagen defect in the inherited form of MDI. These patients also have defective proprioception of the shoulder joint which means that they lose subconscious control of the shoulder.

How does it work?

It was previously thought that capsular shrinkage should burn the tissue and promote scar formation, thus the technique developed a bad reputation. It has also been used for the incorrect indications in the past, thus poor results. However modern thermal capsular shrinkage techniques, as developed at the Reading Shoulder Unit, manipulate the capsular collagen properties only.

The capsule shrinks approximately 10% of its length at when the special radiofrequency probe is applied.  It is has been shown that the capsular shrinkage acts in several ways to stabilise the shoulder:

    1. Mechanical shortening of the capsule in the area that is stretched, by altering the mechanical properties of the collagen in the ligaments and capsule.   
    2. Tightening the proprioceptive sensor feedback mechanism. In the same way that you would use strapping around the shoulder to increase skin sensory input we can improve the shoulder proprioception by tightening the capsule. By re-tensioning the proprioceptors they begin to fire off at lesser degrees of movement, and there is a greater dynamic muscular contribution to shoulder stability

It has been shown that the effects of capsular shrinkage are best when used as part of a good physiotherapy rehabilitation program. Strong shoulder muscles remain the best defence against shoulder dislocation, subluxation, and, thus, instability. Exercises that build up these muscles around the shoulder should be done. Also these muscles need to be trained to work in the correct order again.

As this procedure is done arthroscopically and nothing has been incised or stitched, there is no need to wait to start post-operative physiotherapy. However there is some concern about temporary weakness of the capsule round about 3-6 weeks and hence stretching to regain motion has no part in the early post-operative phase. As soon as pain allows proprioceptive physiotherapy is started. The early results are encouraging but approximately one - third can stretch out with time. It may be necessary to repeat the procedure at a later date if this were to happen. This particular group of patients are difficult to treat even by open surgery and the results of heat shrinkage stabilisation appeared to be comparable.

For Interactive Animations see Interactive Surgery - go to [Shoulder] then [Instability & Labrum Problems] and [Thermal Capsular Shrinkage].

The Operation

This is carried out under a general anaesthetic. It involves tightening the over stretched ligaments and loose capsule deep around the shoulder joint. The surgeon performs the surgery arthroscopically (keyhole).

You must not eat or drink anything after midnight the day before your surgery. When you wake up following the procedure you will be wearing a sling (see picture). The sling should be worn for 3 weeks.

You will probably be able to go home the same day of your operation. A physiotherapist will see you in hospital to teach you the appropriate exercises and you will have outpatient physiotherapy arranged for a Proprioceptive physiotherapy program.

PAIN

You will be given pain killers after surgery for any pain. A nerve block cannot be used, as it may numb the nerves which need to be monitored during surgery. Ice packs may also help reduce pain. Wrap crushed ice or frozen peas in a damp, cold cloth and place on the shoulder for up to 15 minutes. Ensuring you cover the wound site with a piece of cling film to keep the area dry.

THE WOUND

This keyhole operation is usually done through two or three 5mm puncture wounds. There will be no stitches only small sticking plaster strips over the wounds. These should be kept dry until healed. This usually takes 5 to 7 days.

SLEEPING

For the first three weeks your sling must be worn in bed. Sleeping can be uncomfortable if you try and lie on the operated arm. We recommend that you lie on your back or on the opposite side, as you prefer. Ordinary pillows can be used to give you comfort and support. If you are lying on your side one pillow slightly folded under your neck gives enough support for most people. A pillow folded in half supports the arm in front and a pillow tucked along your back helps to prevent you rolling onto the operated shoulder during the night. If you are lying on your back, tie a pillow tightly in the middle (a "butterfly pillow") or use a folded pillow to support your neck. Place a folded pillow under the elbow of the operated arm to support that.

 FOLLOW UP APPOINTMENTS

An appointment will be made for you to see a physiotherapist after your discharge and you will be seen by the Shoulder Team 3 weeks post-operatively.

LEISURE ACTIVITIES

Your physiotherapist and surgeon will advise you when it is safe to resume your leisure activities. This will vary according to your sport and level, as well as the period required to retrain your shoulder muscles with physiotherapy.

 Below is a rough guide: 

DRIVING

You will not be able to drive for a minimum of 3 weeks. Your surgeon will confirm when you may begin.

 RETURNING TO WORK

This will depend upon the size of your tear and your occupation. You will need to discuss this with a member of the Shoulder Team

Proprioception

Proprioception refers to the body's ability to sense movement within joints and joint position. This ability enables us to know where our limbs are in space without having to look. It is important in all everyday movements but especially so in complicated sporting movements, where precise coordination is essential. This coordinated movement is a result of the normal functioning of the proprioceptive system.

The proprioceptive system is made up of receptor nerves that are positioned in the muscles, joints and ligaments around joints. The receptors can sense tension and stretch and pass this information to the brain where it is processed. The brain then responds by signalling to muscles to contract or relax in order to produce the desired movement.

This system is subconscious, and we don't have to think about the movements or the corrections to movement. Sometimes the reactions take place so fast they are termed reflexive.

Following injury to joints and ligaments the receptors are also damaged, which means the information that is usually sent to the brain is impaired. As a consequence the joint feels odd or just doesn't feel right.

Once a joint has been damaged, or a ligament has been torn or partially torn, there will be a deficit in the proprioceptive ability of the individual. This can leave the person prone to re-injury, or decrease their coordination during sport. Proprioceptive ability can be trained through specific exercises and, in the case of the injured athlete, the improvement can compensate for the loss caused by injury. This has the effect of decreasing the chances of re-injury. Proprioception also helps speed an athlete's return to competition following injury. The exercises should be initiated as soon as possible following injury.

19/02/2004