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Extensor tenolysis and intrinsic release of the hand

    Overview

    Learn the Extensor tenolysis and intrinsic release of the hand surgical technique with step by step instructions on OrthOracle. Our e-learning platform contains high resolution images and a certified CME of the Extensor tenolysis and intrinsic release of the hand surgical procedure.
    Adhesions of the extensor tendons can occur following operations or trauma. One of the common causes of extensor tendon adhesions is a fracture fixation of the metacarpal or proximal phalanx. When this occurs in the context of a crush injury hand often there can be scarring of the intrinsic muscles of the hand. This results in a combination of extrinsic and intrinsic tightness.
    To understand the pathology of this condition and to recognise it one needs to understand the anatomy of extensor tendons and instrinsic muscles. The extensor mechanism of the fingers are made up of EDC tendons, EIP and EDM which arise in the forearm. At the MCP joint level they form the extensor hood and continue into the fingers as central slip and lateral bands. The intrinsic muscles, namely the lumbricals and interossei arise in the hand and are attached to the lateral bands. Therefore if there is scarring of the long extensor tendons or the instrinsic muscles patient looses the flexion of the fingers as the lateral bands are not able to move. To differentiate the two, one uses the Bunnell’s Instrinsic tightness test. In this test the PIP joint passive movements are checked with MCP joint in flexion and hyperextension. When there is tightness of the extrinsic muscles, the PIP joint flexion is improved when the MCP joint is hyperextended and the reverse is true with intrinsic tightness. This is because with MCP joint hyperextension the long extensors are relaxed and the intrinsics are stretched.
    Though both lumbricals and interossei are involved in the scarring following a crush injury, it is the lumbrical which usually causes the loss of flexion. Lumbricals originate from FDP tendons and are four in number. The radial two are supplied by median nerve and the ulnar two by ulnar nerve. Lumbricals flex the MCP joints and extend the IP joints.
    The patient in the case series sustained a crush injury to is left hand in an industrial press. He had closed fractures of four metacarpals and three proximal phalanges. They were treated with open reduction and internal fixation. After six months of hand therapy the plate and screws were removed and extensor tenolysis performed. However after six months it was noted that over the middle finger he had reduced flexion and on examination intrinsic tightness test was positive. A revision tenolysis was performed along with intrinsic release.

    Indications

    INDICATIONS
    The indication for performing an extensor tenolysis and intrinsic release is a patient who has loss of flexion from scarring of the extensor tendons and intrinsic muscles. Usually this is following a previous closed injury and a fracture fixation of the metacarpals. Please note that while adhesions of the extensor tendons is a common occurrence following fracture fixation, adhesions of the intrinsic muscles is a rare occurrence and only happens with heavy crush injuries where there has been damage to the lumbricals and interossei.
    Intrinsic release can also be used in patients with Rheumatoid arthritis with intrinsic tightness.
    SYMPTOMS & EXAMINATION
    Patients present with limitation of flexion of the affected finger(s). In Rheumatoid arthritis, they may present with a swan-neck deformity.
    On examination, both active and passive mobilisation of the finger is limited.
    Bunnell’s intrinsic tightness test is the basis for making the diagnosis which is made through clinical examination.
    IMAGING
    Ultrasound scan is useful in demonstrating the scarring of the lumbricals and/or interossei. When the patient has had a previous trauma, X-Rays should be done to make sure that the fractures have healed.
    ALTERNATIVE OPERATIVE TREATMENT
    There are no alternate surgical options.
    NON-OPERATIVE MANAGEMENT
    A trial of conservative treatment is always done before performing a tenolysis. This is through hand therapy for at least four to six months When the patient is reassessed if it is felt that the loss of flexion is from adhesions of the tendons, then a decision to do an extensor tenolysis is made.
    CONTRAINDICATIONS
    A non-compliant patient is a relative contraindication as the success of this procedure is dependent on post-operative hand therapy.

    Setup

    The operation can be performed under a brachial block or general anaesthetic. An upper arm tourniquet is used. The arm is prepped, draped and positioned on the hand table. A single dose of intravenous antibiotic is used as one anticipates opening the MCP joint as part of the tenolysis.

    Operation – 1

    Cascade of the fingers observed
    The hand is positioned on the operating table before prepping. Even with the hand anaesthetised one can note the loss of cascade of the fingers with the middle finger more extended than the ring finger. This is due to the adhesions of the extensor tendon on the dorsum of the hand as well as the tightness of the intrinsic muscles.

    The dorsum of the hand shows the previous incisions used for plate fixation and tenolysis.

    Demonstration of intrinsic tightnessThis test demonstrates the intrinsic tightness in the middle finger. With the MCP joint hyperextended the PIP joint cannot be passively flexed.

    With the MCP joint flexed, PIP joint flexion is improved.
    The explanation of this test is as follows.
    The intrinsic muscles, in this case the lumbricals, are attached to the extensor mechanism i.e. lateral bands. When there is scarring or adhesions of the lumbricals it limits the excursion of the lateral bands thereby limiting finger flexion. When the MCP joints are flexed, the lumbricals are relaxed and this allows more flexion of the finger.
    When there is scarring of the long extensors, the opposite is true. When the MCP joints are flexed the long extensors are tighter and this limits finger finger flexion.

    The hand is positioned on the table. A rolled up Huck towel is useful to position the hand for operations on the dorsum.

    Incision is markedA longitudinal incision is marked over the dorsum of the hand extending into the proximal phalanx. When possible it is best to use the existing incisions for access. The hand is very vascular and alternate incisions can often be made without compromising the circulation. However there is a risk that the intervening tissues may develop impairment of venous and lymphatic drainage a phenomenon called ‘pin-cushioning’ may be seen.

    I find that the cross-hatchings on a longitudinal incision are useful to realign the wound during closure.

    Incision is made using a No.15 blade. It is important to recognise that while doing revision surgery there is no clear plane between the skin and the extensor tendon. It is useful finding a surgical plane proximal or distal to the previous scar and dissect onto the scar. The dorsal sensory nerves are difficult to visualise in the scar tissue and therefore it is best to get down to the plane of the tendon and lift the skin off the tendon.

    The assistant retracts using skin hooks while the skin flaps are raised.

    A self retaining retractor is used to retract the skin. This frees up the assistant to help with the dissection in the deeper plane. However it is important to relax the self-retainer occasionally to avoid constant stretch on the tissues.

    Extensor hood and lumbrical insertion are exposedDissection is performed using tenotomy scissors. The intrinsic muscle commonly involved in intrinsic tightness is the lumbrical which is on the radial side of the MCP joint. It arises from the FDP tendons on the volar aspect and is attached dorsally on the lateral band. Scissor dissection helps to identify the lumbrical tendon.
    Lumbrical muscle can be seen emerging from the volar aspect of the palm on the radial side of the digit. Unlike the interossei, the lumbricals are on the volar side of the inter-metacarpal ligament, and does not have an attachment on the proximal phalanx.

    Extensor tenolysis is doneThough the main tightness is due to adhesions of the lumbricals there are also adhesions of the extensor tendon which have to be released. Extensor tenolysis is performed by separating the extensor tendon from the skin and bone. Once the skin flaps are raised the adhesions from the skin are separated. The separation from deep adhesions need sharp dissection.

    This instrument, called a Mannerfelt dissector is quite useful for performing an extensor tenolysis. It is inserted between the extensor tendon and the bone and sharp dissection done.

    The extensor mechanism over the finger is made up of a central slip and two lateral bands. They are termed radial and ulnar. The central slip is attached to the base of the middle phalanx, whereas the lateral bands are attached to the base of the distal phalanx as the contoint extensor tendon.
    Here the lumbrical tendon can be seen attaching to the lateral band.

    Lumbrical insertion is dividedThe lumbrical tendon and its insertion to the radial lateral band are divided using a No.15 blade. Though the operation is termed intrinsic release, in fact the attachment of the lumbrical on the lateral band is excised as a small triangular segment.

    The extensor tendon following release of the lumbrical tendon is shown.
    Extension of the finger is maintained through the long extensor tendon.

    Intrinsic tightness is checked againThe intrinsic tightness test is repeated. With MCP joint hyperextended, the PIP joint can be fully flexed.

    Some of the proximal adhesions of the extensor tendon are released using scissors.

    Tourniquet is released and haemostasis performed. It is important to get good haemostasis as the tissues are quite vascular after revision surgery.

    Wound closure is doneThe wound is closed using interrupted 4-0 Nylon sutures. Hand therapy will be started the following day and therefore it should be a secure wound closure.

    The closed wound can be seen.

    Intrinsic tightness test is performed once more after the wound closure and demonstrates no residual tightness.

    Dressings are applied.The wound is dressed in layers. It is important to have a layered dressing to provide haemostasis. The first layer is an non-adherent dressing such as jelonet.

    Layers of gauze are applied next followed by velband and bandage.

    Dressings are completed.

    Operation – 2
    Post Operative

    The arm is elevated in a sling and patient is discharged home with analgesics. No plaster or splint is used. Hand therapy is started on the following day if possible. The dressings are reduced and active and passive mobilisation is done as tolerated. Hand therapy is continued on an outpatient basis.
    Hand therapy exercises consist of active and passive movements of the finger both at MCP and interphalangeal joints. Patients are advised to continue these exercises at home. Hand therapy is continued for six weeks.
    Sutures are removed after two weeks.
    Patient is advised to do scar massage and to continue mobilisation.
    Patient can do routine household activities after two weeks. They are allowed to drive once the sutures are removed but in most cases the pain and lack of movements prevent it till at least four weeks.In four to six weeks, patient should be able to resume normal activities. This patient had near normal flexion of his finger after six weeks.

    Recommended Reading

    1.Schneider LH1.Tenolysis and capsulectomy after hand fractures. Clin Orthop Relat Res. 1996 Jun;(327):72-8.
    There are well established operative procedures for salvage of function after fracture healing. When hand therapy measures have not achieved a satisfactory range of motion, it is reasonable to remove any hardware, if present, and lyse tendon adhesions that prevent tendon gliding. The exact cause of restricted motion and the location of adhesions are not always predictable preoperatively, so the surgeon should anticipate additional procedures such as dorsal/palmar capsulectomies in combination with extensor and/or flexor tenolysis. The use of local anesthesia for direct patient input during the procedure offers great advantages. In an ideal situation there should be a demonstrable functional need in a compliant patient with a well healed fracture and workable articular surfaces. Competent hand therapy should be available postoperatively.

    2. Creighton JJ Jr1, Steichen JB.Complications in phalangeal and metacarpal fracture management. Results of extensor tenolysis. Hand Clin. 1994 Feb;10(1):111-6.
    Extensor tendon adherence and joint contracture after phalangeal and metacarpal fracture are common complications that affect finger motion and hand function. The results obtained by extensor tenolysis and dorsal capsulotomy are discussed in this article. Surgical outcome was evaluated as it related to extensor tenolysis and capsulotomy relative to the final total active motion, total passive motion, and active extensor lag. This information will be useful in discussing the expected results of surgery with the patient and in guiding postoperative rehabilitation.

    3. Elfenbein DH1, Rettig ME.The digital extensor mechanism of the hand. Bull Hosp Jt Dis. 2000;59(4):183-8.
    In summary, there is a complex interplay between the extrinsic and intrinsic components of the digital extensor mechanism. Numerous examples of dynamic anatomy and pathology of the extensor mechanism in common clinical settings have been described. Treatment principles have been outlined. This review should provide the orthopaedic surgeon with a framework for management of common hand problem


    Reference

    • orthoracle.com

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