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Technique: Trigger finger-open release

    Overview

    Learn the Trigger finger-open release surgical technique with step by step instructions on OrthOracle. Our e-learning platform contains high resolution images and a certified CME of the Trigger finger-open release surgical procedure.
    Triggering of digits (stenosing tenovaginitis) is most common in women between 50-60 years of age. The thumb and ring fingers are the most commonly effected digits with the right hand more commonly effected than the left.
    Most cases are idiopathic although certain factors such as repeated power gripping or trauma may be causative. This section does not discuss congenital trigger thumb/finger which has a different pathology and treatment pathway. Medical conditions such as diabetes, gout and rheumatoid arthritis have also be implicated in the development of the condition.
    The issue occurs at the A1 pulley due to narrowing of the flexor sheath or bulging or of the tendon causing pain and restriction in movement. The pathological process which occurs at the A1 pulley is an evolution from dense compact parallel collagenous bundles to an irregular patter of fibrous tissue with chondroid metaplasia of the pulley with deposition of hyaluronic acid, chondroitin sulfate and proteoglycans.
    On the palmar aspect of the hand there are commonly 2 transverse creases. The proximal and distal palmar crease. These creases are created as the metacarpophalangeal joints (MCPJs) flex and are arranged in an overlapping fashion due to the length of the metacarpals with the middle finger longest, then the index, then the ring and finally the little. The distal palmar crease starts at the junction of the glaberous and non-glaberous skin on the ulnar side of the palm and extends, drifting slightly distally, level with the second web space. The proximal palmar crease extends from the radial border of the hand at the junction of the glaberous and non-glaberous skin starting at the same distal to proximal distance along the palm, drifts slightly proximally and terminates level with the 4th web space.
    Open release of the A1 pulley is a procedure usually performed for recurrent of persistent triggering refractory to non-operative treatment. The procedure can be performed as a day case under local anaesthetic and takes around 15 minutes for an experienced surgeon. The patient has a simple dressing and is asked to mobilise as able as does not usually require any hand therapy input. After 3-6 weeks the scar softens and full use of the hand, including tight gripping, is possible.

    Indications

    Indications
    Recurrent or persistent trigger finger refractory to non-operative management.
    Symptoms
    The symptoms experienced vary and a spectrum is described which can be graded as per Froimson (1999) in order of increasing severity as follows:
    Pain and catching in the patient history but not on examination. Occasional tenderness over the A1 pulley – these patients often complain of catching of the finger which can remain in a flexed position in particular on tight gripping or first thing in the morning. This will then straighten with pain and a click on active extension of the proximal inter-phalangeal joint (PIPJ) will be felt.
    Demonstrable locking of the finger in flexion during examination but with an ability to actively extend the MCPJ and PIPJ with a painful click.
    Demonstrable locking of the finger in flexion during examination but with an ability to extend the MCPJ and PIPJ only with passive force and with a painful click.
    Finger locked in the flexed position – this is very painful initially but may actually become less painful if locked for a long period.
    Patients often complain of pain over the dorsum of the PIPJ and will describe this joint as clicking or dislocating despite the pathology being volar in the region of the A1 pulley.
    Examination
    A patient with trigger finger will usually be tender over the A1 pulley of the finger which lies over the neck and proximal head of portion of the head of the metacarpal.
    The A1 pulley of each finger can normally be palpated during active flexion of the finger. The A1 pulley of the finger can be located by a number of methods.
    The distance between the MCPJ crease and the A1 pulley is roughly the same as the distance between the MCPJ crease and the PIPJ crease.
    If the finger is fully flexible the A1 pulley is located where the tip of the finge touches the palm if passive pushed into a tight curl.
    The index A1 is just distal to the proximal palmar crease, the middle finger A1 is at the level of the distal palmar crease, the ring finger A1 is just distal to the distal palmar crease, the little finger A1 is just distal to the distal palmar crease. When locating the A1 pulley it is also important appreciate the direction of the tendons which travel from the finger through the carpal tunnel. This means that the middle and ring fingers head directly proximal towards the wrist and the little and index flexor tendons converge towards the midline into the carpal tunnel making the A1 pullies of these 2 fingers more centralised. If the fingers are fully abducted and a line is drawn along their midline this line will cross the A1 pullies.
    Patients may also be tender over the dorsum of the PIPJ and an insertional tendonitis of the central slip of the fingers extensor tendon may be caused due to the additional force required to straighten the joint.
    Over the A1 pulley there may be a visible or palpable lump over which crepitus may be felt during active flexion and extension of the PIPJ.
    Triggering may be associated with Diabetes, Rheumatoid Arthritis and Gout and therefore evidence of these conditions may also be sought.
    As noted in the classification a patient may be able to move their finger smoothly during the examination or show clear catching and triggering or even be locked in a flexed or more rarely and extended position.
    Investigations
    Trigger finger is usually a clinical diagnosis however an ultrasound scan is the investigation of choice if required.
    This modality not only assesses the soft tissues in a dynamic fashion but also can act as an adjunct to administration of a steroid injection.
    Non-operative Management
    Trigger finger may often be self-limiting and therefore avoidance of aggravating postures such as tight gripping may allow the condition to resolve.
    Non-operative management for trigger finger includes, analgesia, splintage at night (with the MCPJ and PIPJ straight) and steroid injection into the flexor sheath.
    The steroid injection can be placed in the palm at the level of the A1 pulley or over the proximal phalanx.
    In our practice we will provide non-diabetic patients with 2 injections before progressing onto surgery and diabetic patients a single injection due to the poorer prognosis and effectiveness in diabetic patients.
    Alternative operative Management.
    Alternative procedures for trigger finger include a percutaneous method of release.
    Contraindications.
    These are all relative.
    Not having tried non-operative methods of treatment.
    Poor overlying skin – eczema etc will be best optimising before offering surgery.
    Untreated resolvable condition with may cure the triggering if treated – e.g. rheumatoid flare.

    Setup

    Pre-operative preparations and Equipment
    The procedure can be performed under local anaesthetic with or without adrenaline. If adrenaline is not used then a forearm or arm tourniquet inflated to 250mmHg is used for the duration of the procedure.
    The operation takes around 15mins to do safely.
    Skin hooks, Ragnell retractors or an Alms retractor are used to aid access and a 15 blade and tenotomy scissors are used for sharp and blunt dissection.
    Loupes magnification are used.
    The hand may be held flat by a lead hand or similar supporting device during the procedure.

    Operation
    Location of neuromuscular bundles, tendon and chevron incision marked on skin For this release of the index finger A1 pulley the hand can been seen marked with 3 straight lines. A central longitudinal line representing the flexor tendons entering the carpal tunnel between the scaphoid tubercle (Sc) and Pisiform (P) marked. A line either side is used to represent the neurovascular bundles which gently converge on the tendon more proximally. The chevron shaped incision (Inc) can be seen centred over the tendons at the level of the distal palmar crease.
    Local anaesthetic injected proximal and around the incision site The local anaesthetic is injected just proximal to the marked incision and superficial to the A1 pulley. 3mls of 1% lidocaine and 3mls of 0.5% Bupivacaine is used. The injection is central over the A1 pulley which in old patients with poorer connective tissue can spread around the whole operative area. In younger patients the needle is inserted deeper just above the tendon and the radial and ulna over the neuromuscular bundles to inject in the 3 sites from the single skin puncture.
    The skin is incisedThe incision is a chevron shaped incision at the level of the distal palmar crease.
    Skin hook used to retract tip of flap to complete deep dermal incisionWith a 15 blade the tip of the flap is mobilised to reveal the fat beneath. Use of a skin hook avoids holding the skin multiple times and traumatising its edges as occurs with the use of forceps.
    Blunt dissection with scissors centrally down to tendon sheathIf the dissection is kept directly over the flexor sheath then the neurovascular bundles are not routinely seen, as in this case.
    An Alms retractor as Ragnell used to visualise the pulleysThe Ragnell can also be used for some blunt dissection the mobilise the fat distally and proximally. The flexor sheath is seen beneath the fat. It can be more clearly viewed using a dry swab to rub over the sheath and clear the fibrous tissue.
    The flexor sheath is now more clearly seen with fat proximally and annular fibres of the A1 pulley more distally.
    The A1 pulley is defined at its proximal and distal endsA Watson-Cheyne elevator is placed in the distal mouth of the A1 pulley (A).
    The pullies can now be seen more clearly. In the wound from left to right (proximal to distal) yellow fat, pink synovium, white pulley (accessory annular pulley), pink synovium, white A1 pulley, white A2 pulley. The Watson-Cheyne elevator(A) coming from the bottom of the picture is held at the level of a darker line in the annular fibres between the A1 and A2 pulley.
    The A1 pulley is sharply incised centrally.The pullies are incised in line with the tendon fibres beneath. The whole of the accessory pulley and the A1 pulley is divided.
    The accessory and A1 have been incised along their midline.
    Thickened synovial proximal to the pulley is divided
    Proximal 20% of a2 pulley dividedThe most proximal twenty percent of the A2 pulley is now released, and can be seen held in the tooth of the forceps. This proximal end of A2 is often also tight an in the zone of tendon thickened and therefore is routinely released in the authors practice. Enough of the A2 remains to be fully functional.
    The 3 released pullies can be seen in the wound.
    This is a picture of the middle finger also released during the procedure. Often the junction between the A1 and A2 pullies can be very difficult to see and an excessive amount of A2 may be released if care is not take which may result in tendon bowstringing. One technique to identify the junction is to release the A1 pulley and evert it as it is released (as demonstrated in the picture). From above, the pullies may seem continuous, however from beneath the light can flow through the thinner film between the pullies making their definition clear.
    The FDS and FDP are lifted out of the wound and inspectedAny adhesions between the tendons can also be divided at this point. In the picture a reddened area of tendon can be seen with a small area of attrition from the trauma against the A1 pulley during the irritation of triggering. If using a lead hand to support the fingers, remember to release the finger to allow elevation of the tendons.
    The wound is closed with dissolvable sutures, 4/0 vicryl rapide.
    The wound is dressed with an occlusive dressingThe dressing is larger in this case as 2 fingers were released.
    A bulky bandage is applied leaving the fingers free to mobilise.
    Post Operative

    The procedure is performed as a day case and the patients are discharged with a simple triangular sling to use for 24 hours.
    They return within a week for wound review and only require hand therapy if they have marked difficulty moving the finger at this point.
    We provide paracetamol and ibuprofen on discharge.
    The wound is redressed with an adherent dressing and remains covered until 10 days when the patient can start to wash their hand as normal and the dissolvable sutures will fall out over the following few days.
    Patients are advised to mobilise their finger straight away, massage the scar after 2 weeks and avoid tight gripping and lifting for 4-6 weeks.
    The final review a 3-4 months is booked to assess the final result and help resolve and continuing scar issues if present.

    Recommended Reading

    Complications of trigger finger release can occur in up to a third of patients. These are however usually minor resolvable issues such as scar tenderness, wound dehiscence, stiffness and swelling. It is very rare to have a significant nerve injury.
    The British society for the Surgery of the Hand (BSSH) published evidence based management advice of trigger digits in October 2016, the BEST guidance. This includes an overview of the condition and a review of the papers looking at its treatment.
    Below are a few papers for further reading:
    ES. Sato et al. Treatment of trigger finger: randomized clinical trial comparing the methods of corticosteroid injection, percutaneous release and open surgery. Rheumatology, 2012, 51(1):93–99.
    This RCT of 150 fingers with a compared steroid injection, open and percutaneous release with a minimum follow up of 6 months. In the injection group there was a 57% cure rate with a single injection which increased to 86% with a second injection. 100% of the open and percutaneous releases were cured at 6 months. No nerve injuries or serious complications were seen in any group.

    Hansen RL, Sondergaard M, Lange J. Open surgery versus ultrasound guided corticosteroid injection for trigger finger: A randomized controlled trial with 1 year follow-up. J Hand Surg Am. 2017 May;42(5):359-366
    This RCT of open release versus ultrasound guided injection recruited 165 patients with a 12 month follow up. At 3 months 86% of injections and 99% of open releases were cured. At 12 months 49% and 99% remain cured respectively. Complications in the open group were more severe with 3 superficial infections and 1 iatrogenic nerve injuries. In the injection group 11 patients experience steroid flare and 2 experience fat necrosis.

    Comparing the above 2 studies it would suggest that there is a higher success rate with ultrasound guided injections however a high percentage of these ware off with a recurrence of trigger finger symptoms by 12 months.

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