Shoulder Arthroscopy and Arthroscopic Surgeries
Lanny Johnson, the father of shoulder arthroscopy, stated twenty years ago that any operation on the shoulder joint itself or on the tissues nearby should be preceded by or combined with an arthroscopic examination. This statement was highly controversial at that time when it was made but is true today. Shoulder arthroscopy has evolved over the last 2 decades and most of the soft tissue problems in and around the shoulder can be treated successfully with arthroscopy, the results being equivalent or superior to that of the open procedure.
The following are common arthroscopic procedures done in the shoulder:
- Sub acromial Decompression (Bursectomy + Acromioplasty).
- Resection of Lateral end of clavicle.
- Removal of Calcific Deposits in the cuff.
- Rotator cuff repairs.
- Bankart repair and Bankart shift.
- Plication of the Capsule.
- SLAP repair.
- Capsular release.
- Suprascapular nerve release.
- Brachial plexus catheter placement for post OP pain control.
ROTATOR CUFF TEARS – The MIOT Approach
Rotator Cuff tears may be degenerative or traumatic. In both categories a strong association of Type 3 acromion as well as osteophytes along the inferior aspect of the acromioclavicular joint has been reported.
A rotator cuff tear can manifest clinically as mild shoulder pain to complete loss of function in the shoulder. Night pains and sleep disturbances are very common. It can be diagnosed by various clinical tests described for each and every muscle in the cuff crescent. For supraspinatus 0o Abduction strength test, For InfraSpinatus and Teres minor – dropping arm test and Horn Blower’s test, for subscapularis – belly press test and lift-off test. The cuff tears can be confirmed with an MRI / MR arthogram (more preferred).
Once a cuff tear is confirmed it needs intervention. Arthroscopic rotator cuff repair is the preferred approach in our institute. It avoids the compromise of the deltoid origin seen in the conventional open approach or a difficult retraction of the deltoid fibers seen in the Mini – Open repair. Before an intervention is decided, one should be aware of an entity – the irreparable rotator cuff tear. This is revealed by the following:
- Tangent sign +.
- Retraction of the tendon beyond the level of the glenoid margin
- Severe advanced fatty degeneration of the muscle.
- Stiff shoulder.
In these cases, rest of the cuff tears should be advised. Once a thorough 15 point Glenohumeral diagnostic arthroscopy (SNYDER) is completed, a quick subacromial decompression (SAD) has to be performed otherwise a tense swelling in the shoulder makes an arthroscopic repair difficult. Once the SAD is over, the first step is to asses the nature of the cuff tear using various classifications.
I. Based on the thickness of the cuff tear
- Partial articular side tears.
- Partial bursal side tears.
- Complete tear.
Complete tear requires repair as well as partial thickness tears involving more than 50% thickness of the cuff with cuff symptoms and non degenerative tears with less inflammation in the bursa. Other partial tears can be debrided and left alone.
II. Based on the Shape of the tear
- Crescent Shaped.
- L – Shaped.
- U – Shaped.
Assessment of tear configuration is very important to decide the type of repair.
III. Based on the Retraction of the tendon
- Grade I – Torn without significant retraction.
- Grade II – Torn and retracted up to mid head of humerus.
- Grade III – Retracted to the gleonoid level.
The greater the retraction, higher the chances that the cuff substance is adherent to the surrounding structures and most likely a release should be performed.
IV. Based on the tendon which it involves
- Supraspinatus / Infraspinatus / Subscapularis.
- This helps us to decide in which direction the tendon has to be pulled and mobilized for reattachment.
V. Based on the Size
- Size up to 1cm – small.
- From 1cm to less than 3cm – medium.
- 3cm to less than 5cm – large.
- More than 5cm – massive.
The size conformation helps to decide a single row repair or a double row repair and also the number of suture anchors to be used.
Once the nature of the tear is assessed then the cuff mobility is checked. The torn cuff tendons must be reattached to a mechanically favorable site on the bone bed without undue tension on the repair. A tension free repair is essential for successful healing of the tendon. The most important pre requisite for healing of a biologically repaired tissue is the structural integrity of the entire construct. A loose suture or poorly placed anchor can mean loss of integrity of the entire construct.
The suture anchor must be placed at an angle of 45o to the bone (Deadman angle), so it can resist the pullout forces to the maximum. Loop security and knot security are important. Each suture (Non absorbable Ethibond & etc.) can resist a load of 35-40 N with the entire knot configuration except the one which has all the half hitches thrown in the same direction. We use the sliding hangman knot followed by half hitches in different directions and alternately changing the post. When a large tear is repaired, at least 6 fixation points (leaving the two existing fixation points – either ends of the cuff tear) are required. This means at least 3 suture anchors each with two sutures will be needed for the repair of the large tears.
We prefer to use double row repair technique in all the tears except small tears. Single row repair reattaches the tendon to the outer margin of the foot print. This may cause a windshield wiper effect between the cuff and the tuberosity. This shear force may hamper healing. A double row repair puts the whole cuff tendon under compression and increases the contact area over the bone. This creates a favorable environment for the healing of the tendon. The inner row anchors are placed at the juxta artcular margin and the outer row anchors at the summit of the greater tuberosity. One should be careful not to remove the cortical bone over the tuberosity. Preparation should stop at the level of bleeding bone.
Once the suture anchor is placed, suture capture of the tendon is performed with the help of any one of the instruments (eg. Suture hooks, Tissue penetrators, Scorpio, etc). The inner row sutures are passed at the musculo tendinous junction and the outer row sutures are passed 5-10mm from the free margin of the cuff. We prefer mattress suture for inner row and simple or lasso loop stitch for the outer row.
Suture entanglement and inadvertent pulling of the suture out of the anchor must be avoided. Twists must be removed before the knot is tightened. The slack between the half hitches must be removed by past pointing every time.
Crescent shaped tears are directly reattached to the bone bed. But an ‘L’ shaped tear repair first starts at the corner reattachment. Then the vertical limb is approximated (Marginal convergence) leaving the knots over the posterior leaf to avoid suture impingement. Finally, the horizontal limb is reattached to the bone bed, using suture anchors. The same technique is used for the repair of ‘U’ shaped tears. The vertical limb is approximated first (Marginal Convergence) following by reattachment of the horizontal limb to the bone bed by suture anchors.
When the tendon is not freely mobile, a release technique is performed, – peri-tendinous and peri-glenoid releases are done first. If it is still not mobile, then the interval slide is performed.
When the tear involves the attachment of the coracohumeral ligament, it retracts back to the coracoid process taking the cuff tendon along with it. Without releasing the coracohumeral ligament from the cuff or from the coracoid process it may not be possible to reattach the tendon to the desired place. The release of the coracohumeral ligament is achevied with the Interval slide done at the level of the rotator interval.
When a ‘U’ shaped tear involves infraspiratus the posterior leaf has to be proximalised and even when a complete repair is not possible and part of the superior surface of the head is visible one should continue to do a partial repair to balance the force couples between the anterior fibers and the posterior fibers. This balance helps the shoulder joint to establish a stable fulcrum of glenohumeral motion. Without understanding shoulder mechanics, trying to cover a rent in the cuff may make the shoulder worse.
Rehabilitation Protocol : There are four phases
Phase I : (0-6 weeks)
Patient is protected with a shoulder immobilizer when they are not doing the exercises particularly at night. During this period active elbow motion exercises and grip strengthening are allowed. Passive shoulder mobilization exercises are started and based on the nature of the tear and the stability of the repair we allow upto 120o forward elevation and 20o external rotation.
Phase II : (Is from 6-12 weeks)
Sling is discarded. Full possible motion, active assisted exercises are started and then we progress to active motion exercise.
Phase III : (From 12-16 weeks)
Strengthening exercise and stretching exercise to get a full range of movement are advised at this stage.
Phase IV : (After 16 weeks)
Once original strength is regained, patients can return to labour intensive occupations and sporting activities.