//

Trigger thumb release

    Overview

    Learn the Trigger thumb 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 thumb 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 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 thumb there are 3 main flexion creases. These are the crease of the IPJ and a proximal and distal crease over the MCPJ which are spaced around 5-10mm apart. The A1 pulley of the thumb is consistently at the level of the proximal most of the two MCPJ creases.
    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 15mins 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 thumb 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 thumb 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 inter-phalangeal joint (IPJ) will be felt.
    Demonstrable locking of the thumb IPJ in flexion during examination but with an ability to actively extend the IPJ with a painful click.
    Demonstrable locking of the thumb IPJ in flexion during examination but with an ability to extend the IPJ only with passive force and with a painful click.
    Thumb (digit) 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 IPJ 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 thumb will usually be tender over the A1 pulley of the thumb which lies beneath the proximal of the two MCPJ creases. They may also be tender over the dorsum of the IPJ and an insertional EPL tendonitis 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 IPJ.
    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 thumb 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 thumb 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 thumb 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 thumb includes, analgesia, splintage at night with the IPJ 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 thumb 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 is used.
    Although the thumb can be held in a Lead hand or similar support, it is often simpler for an assistant, if available, to hold the thumb in position for the duration of the operation.

    Operation

    A1 pulley and neurovascular bundles are marked on the skin
    To safely approach a trigger release of the thumb the exact location of the neurovascular bundles must be appreciated. The thumb itself lies at 90 degrees to the fingers of the hand and has its neurovascular bundles more centrally placed than the fingers in which the neurovascular bundles (at the level of the A1 pulley) lie demonstrably off-centre and either side of the flexor sheath.
    This diagram shows the more central position of the neurovascular bundles drawn on the thumb and the level of the A1 pulley over the MCPJ crease. The diagram also reveals how the nerves converge more proximally (marked A) to travel through the thenar eminence with the FPL tendon.

    Local anaesthetic is injected proximal and above the A1 pulley.A mixture of 5mls of 1% lidocaine and 5mls of 0.5% Bupivacaine is sufficient.

    A chevron incision is marked, centred over the A1 pulley/MCPJ crease (A).

    The chevron skin marking is sharply incised.The surgeon must take care as the neurovascular bundles are very superficially located in this region.

    Skin hooks are used at the tip of the chevron to elevate the skin flap.

    The skin flap is elevated to expose the subcutaneous fat.

    The tenotomy scissors are placed centrally to spread the fat off the underlying flexor sheath.

    The thickened flexor sheath (FS) is exposed centrally.

    Beneath the skin flap the ulnar digital nerve can be seen (N). The thickened tissue over the flexor sheath is indicated by the tip of the scissors.
    The surgeon does not need to formally dissect out the neurovascular bundles of the thumb however the one in the base of the chevron incision of is exposed during the initial dissection to the flexor sheath.

    A swab is used to sweep away any fat and tissue over the flexor sheath. A blunt Wests self retainer is placed on the skin (avoid placing it on the nerves) and Ragnells retractor is inserted proximally and distally to clearly expose the white thickened flexor sheath and A1 pulley.
    The A1 pulley is annotated on the picture – the A1 is the proximal most thickening of the flexor sheath.

    The pulley is incised centrally in line with the fibres of the tendon throughout its length.A blade can be directly used over the tendon careful not to cut too deep, however as the blade is kept in line with the tendon fibres as small cut in the tendon would cause a longitudinal split only and therefore not affected the integrity and strength of the FPL.

    Scissor are spread at either end of the pulley to ensure no fibres or thickened synovial remain.The FPL can be seen within the opened flexor sheath.

    The FPL tendon is lifted out of the sheath with a Ragnell retractor to check for any adhesions.A minor area of attrition can be seen on the FPL tendon when lifted from the sheath. This is more common the more severe of chronic the condition is. Thickened synovium can often be seen around the tendon and in many cases the deposition of steroid powder from previous injections may be identified.

    With the FPL dropped back into the sheath the scissors can be seen pointed at the distal end of the exposure. Here can be seen the smooth edge of the oblique pulley which has been left intact.

    The Radial digital nerve is seen running adjacent to the FPL tendon (N).

    The patient is asked to fully flex and extend thumb to ensure triggering has settled.

    A smooth glide of the tendon should be noted.

    The wound is then closed with 4/0 vicryl rapide, an absorbable suture.

    An adherent dressing is applied.

    A wool and crepe bandage is applied for comfort for a few days.

    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 thumb 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 sutures will fall out over the following few days.
    Patients are advised to mobilise their thumb 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 and thumb 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 a the papers looking at its treatment.
    Below are a few papers for further reading:
    Lange-Riess D1, Schuh R, Hönle W, Schuh A. Long-term results of surgical release of trigger finger and trigger thumb in adults. Arch Orthop Trauma Surg. 2009 Dec;129(12):1617-9.
    This paper looks the long term results of 305 trigger finger or thumb releases. Mean age at operation was 46.2years with around two thirds female. The mean follow up was 14.3 years. 234 patients were reviewed and no recurrence nor major complications such as nerve injury or bow-stringing of the tendon noted.
    R. Will, J. Lubahn. Complications of Open Trigger Finger Release. J Hand Surg. 2010;35A:594–596
    The authors retrospectively reviewed 78 cases of open trigger release performed by a single surgeon. There were 2 major complications (3%). One synovial fistulae and one PIPJ arthrofibrosis needing further treatment. There were 22 minor complications (28%) including stiffness, scar tenderness, pain and wound erythema.
    Although major complications are rare. Minor complications are shown to be relatively frequent and patients should be consented accordingly.

    Mardani-Kivi M et al5. Intra-sheath versus extra-sheath ultrasound guided corticosteroid injection for trigger finger: a triple blinded randomized clinical trial. Phys Sportsmed. 2018 Feb;46(1):93-97.
    The authors of the RCT compared ultrasound-guided corticosteroid injections for trigger finger sited intra or extra sheath. 166 patients were injected at the level of the A1 pulley intra or extra sheath. No difference in severity or patient demographics were noted between groups. In both groups 94% of patients were symptoms free at final review.
    This study would suggest that similar results would be seen with injections provided with or without ultrasound guidance.

    Reference

    • orthoracle.com

    Tags:

    You might be interested in

    Dark mode powered by Night Eye