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Lag screw fixation of a proximal phalanx fracture using Synthes® 1.5 mm Compact Hand Set

    Overview

    Learn the Lag screw fixation of a proximal phalanx fracture using Synthes® 15 mm Compact Hand Set surgical technique with step by step instructions on OrthOracle. Our e-learning platform contains high resolution images and a certified CME of the Lag screw fixation of a proximal phalanx fracture using Synthes® 15 mm Compact Hand Set surgical procedure.
    Proximal phalangeal fractures are fairly common, with their incidence being second only to the metacarpal fractures in the hand. Malunion of these fractures can result in scissoring of the fingers or pseudoclawing, which interfere with the normal function of the hand. Reduction, stabilization and early mobilization are essential for optimal outcomes following this injury.
    Readers will also find of interest the following OrthOracle technique Internal Fixation of Proximal Phalanx with Synthes® 1.5 mm Compact Hand Plate

    Indications

    INDICATIONS
    Strickland et al recognized that reduction and stability of the fracture along with length of immobilization are directly related to digital performance. Rigid stabilization allows immediate early mobilisation of the digit. I believe that the indications for internal fixation of proximal phalangeal fractures with lag screws are:
    Open injuries
    Fracture associated with tendon, ligamentous or neurovascular injuries
    Malrotation or angular deformity of the digit. (No angular or rotational deformity is acceptable for full functional recovery.)
    Displaced intra-articular fractures
    SYMPTOMS & EXAMINATION
    Proximal phalangeal fractures occur following an episode of trauma. This may involve a fall on the hand, a blunt impact on the finger or a twisting injury to the finger. It may also be seen in patients involved in significant polytrauma. Unlike the metacarpal neck fractures, phalangeal fractures do not always result from punching injuries. They are usually isolated injuries but may occasionally be present in multiple digits. There is no age predeliction for these injuries. The injuries are equally distributed between dominant and nondominant hands.
    The patient presents with a painful, swollen and often deformed finger. The finger should be examined for any rotational or angular deformity on presentation. Malrotation is assessed by noting any scissoring of fingers on attempted flexion. Comparison should always be made with the contralateral side. Associated injuries to the tendons and neurovascular structures should be identified. Definitive diagnosis is based on radiographic evaluation.
    IMAGING
    Plain radiographs in AP and lateral plane are usually sufficient to identify the fracture pattern and displacement. Special views are usually not required to identify the injury or plan management.
    A true lateral view is essential in confirming the displacement. Angular and rotational deformities are dependent on the original deforming force of the trauma. Intra-articular extension of the fracture should be identified on the radiographs. Any comminution of fracture fragments should be identified.
    ALTERNATIVE OPERATIVE TREATMENT
    Manipulation and splintage: This is useful for stable fractures only. However, the reduction needs to be monitored closely with serial weekly radiographs. In addition, the prolonged immobilization required to maintain reduction can be counterproductive for regaining finger function.
    Closed reduction and K wiring: This provides better stability and is useful for unstable fractures. Multiple K wire configurations have been described in literature with varying results. Belsky wiring, Single intramedullary wires and crossed K wires have all been shown to have complications of infection, stiffness and metalwork failure. In addition, K wires do not provide rigid stability to allow immediate mobilization. They are also not appropriate for comminuted fractures and for those involving bone loss.
    Internal fixation with plates: Although this provides good rigid stabilisation, the procedure carries an inherent risk of increased tendon adhesions and stiffness. The technique is best reserved for comminuted fractures, segmental fractures and those involving bone loss.
    NON-OPERATIVE MANAGEMENT
    Non-operative management should be considered and discussed with the patient. Patient buy-in for the rehabilitation process is extremely crucial for a successful outcome and should be reiterated before planning definitive management for these injuries. Manipulation and splintage is a viable alternative proposed by a number of authors in the literature. The finger needs to be splinted with the MCPJ in flexion and the PIPJ in varying degrees of extension to reliably maintain the fracture reduction. Serial radiographs followed by intensive physiotherapy, to overcome the resultant stiffness, are the mainstay of a nonoperative treatment method.
    CONTRAINDICATIONS
    The main contraindication for this procedure is a multifragmentary fracture configuration with or without bone loss. These require alternative modes of fixation (plates and screws or external fixators) to achieve adequate stability. Other contraindication for definitive fixation is a patient who is not fit for anaesthesia and surgery. However, in my experience, an unsure patient who carries misgivings about any surgical intervention, is a relative contraindication for internal fixation.

    Setup

    Informed consent is an important part of the procedure and the risks and benefits should be clearly explained to the patient. The metalwork lies in close proximity to the articular surface and the extensor tendon. The patient should, therefore, be always counseled regarding the risk of tendon adhesions and stiffness necessitating removal of metalwork after the fracture is healed.
    I prefer regional anaesthesia with axillary block for this procedure. The patient is placed supine with the limb extended on an arm table. Upper arm tourniquet is applied and inflated after exsanguination. A prescrub is performed followed by a sterile prep with Chlorhexidine. A lead hand is used to stabilize the hand. I routinely administer a single dose of antibiotics for this procedure

    Operation

    Note the spiral fracture in the shaft of proximal phalanx. There is no comminution of the fracture fragments visible on these radiographs. There is no bone loss identifyable.
    The radiographs also confirm shortening at the fracture site. The rotational abnormality may not be readily visible on X-rays, confirming the need for good clinical assessment of the patient’s finger – as seen in the next image.

    Preoperative clinical indication of malrotation is idnetified by scissoring of the fingersNote how the ring finger “scissors” over the small finger. This is a sign of malrotation and an indication for intervention.

    Dorsal longitudnal skin incision marked on the finger for approachA dorsal midline longitudinal incision is planned overlying the proximal phalanx.
    Some surgeons advocate a lateral approach and fixation. The argument for a lateral fixation is the theoretical advantage of reducing tendon adhesions. However, visualisation and reduction of fracture fragments is usually inadequate via a lateral approach. In addition, as the web of the finger lies at the level of midshaft of the proximal phalanx, a lateral incision will often result in web scar contracture.
    On balance, I feel that a dorsal approach is more suitable for fractures at the base of the proximal phalanx. The surgical exposure of the fracture site is excellent and there is minimal problem with scar contracture during recovery.

    Skin incision is made along the dorsum for approach to extensor tendonsThe skin is incised with a No.15 blade. The subcutaneous tissue is incised with sharp dissection and the skin flaps retracted. Dorsal subcutaneous veins are cauterized along the way. The extensor tendons to the finger are exposed immediately beneath the subcutaneous tissue.

    Exposure of extensor tendons underneath the subcutaneous tissues and identifying the central slip and lateral bandsThe central slip of the extensor tendon lies longitudinally in the midline and is straddled on either side with the lateral bands of the extensors. There may be bruising evident over the extensors in a fresh injury.
    The digital neurovascular bundles lie on the volar aspect of the finger and are well protected from injury in this approach
    In this image the longitudinal tendon incision has already been made, the tendon split and retracted.

    Exposure of the bone and the fracture after splitting the extensor tendons longitudinallyThe proximal phalangeal bone can be approached through the interval between lateral bands and the central slip. Incision is made with the blade right onto the bone, dividing the periosteum. A periosteal elevator is used to elevate the periosteum off the bone. I do not routinely elevate the tendon and periosteum as separate flaps.
    A self retaining retractor is used to elevate the skin flaps. The fracture is now clearly exposed. I do not routinely wash the fracture haematoma unless I feel there is soft tissue interposition that is likely to prevent adequate reduction.

    Fracture reduction using traction, manipulation and bone clampsThe fracture is disimpacted and reduced with longitudinal traction applied to the fingertip. The surgeon simultaneously derotates the distal fragment, thereby realigning the fragments.
    Once aligned, the reduction can be fine-tuned using a bone reduction clamp. The clamp is partially applied in an oblique fashion with the nearside limb more proximal than the far-side limb. The clamp is then rotated and tightened so as to lie in a transverse plane. This corrects the final displacement – reducing the fracture anatomically. This technique can be used in a 3-dimensional plane to correct anteroposterior malalignment as well.

    Stabilising the fracture reduction with a second clampThe 1st reduction clamp always seems to lie in the location which is ideal for placement of the lag screw and can hinder this surgical step. Therefore, a second clamp may now be applied to allow for repositioning of the primary clamp so as to allow comfortable placement of the lag screws.

    The Synthes® 1.5 mm Compact Hand System, used in this instance, contains a variety of plate designs. (A new addition to the Synthes system is the LCP set with provision of locking plates.) The screws on this set have a thread diameter of 1.5 mm and all screws come with self tapping threads. The set includes 1.1mm and 1.5mm drill bits. The plates are available in different designs but will not be used in this particular fracture fixation.
    The advantage of using a Synthes system is the ease with which you can upsize or downsize on the screws depending on the size of the fracture fragments (the 1.3 mm and the 2.0 mm Compact Hand System)
    For proximal phalangeal fractures, a 1.5 mm system is ideal for fixation.

    Gliding hole for the 1st lag screw with 1.5 mm drill on the near cortexA 1.5 mm drill bit is used to drill the near cortex. This is the “gliding hole” which will prevent coupling of the screw to the near cortex. A drill sleeve is used to protect the soft tissues. The direction of the drill hole should be perpendicular to the fracture to allow compression at the fracture site (+/- 20 degrees) as shown by Johner et al (1983)

    Completing the pilot hole with smaller drill of 1.1 mm across the far cortexA 1.1 mm drill sleeve is introduced into the gliding hole of the near cortex. This helps to better orient the direction of the remaining procedure. Drilling is stopped as soon as there is a “give” in the resistance which signifies a penetration of the near cortex .A 1.1 mm drill bit is now used to complete the pilot hole across the far cortex.

    Meaure the screw length with depth gaugeThe screw length is measured with the depth gauge provided. Note the direction of the hole, which is perpendicular to the fracture surface.
    The distance between the screw hole and the fracture plane should ideally be equal or greater than the diameter of the screw head. This is to prevent propagation of the fracture and splintering of the bone bridge. This particular screw is a bit closer to the fracture plane and as we will see in later pictures, there is some propagation of the fracture in the intervening bone bridge.

    Insertring the 1.5 mm lag screw for secure fixationA countersink may be used on a manual handle onto the near cortex. This allows better fixation of the screwhead into the bone. It also prevents protrusion of the screwhead, thereby minimizing irritation of the soft tissues.
    The appropriately sized screw is inserted into the previously drilled hole and tightened. I always look for and note the compression at the fracture site as the screw is tightened.

    Visual confirmation of fracture reduction The fracture reduction is checked. Check X-rays can be taken at this stage to confirm the fracture reduction and the screw length.

    Clinical confirmation of correction of deformity with no scissoring of the fingerNote that the scissoring of the ring finger is now resolved. This clinical confirmation is important before proceeding to the next stage of the procedure

    Insertion of the 2nd lag screw to secure further fixationIf the reduction on examination and the radiographs is satisfactory, inserting the 2nd screw distally completes the fixation.
    Note that the second screw may not lie in the same plane as the first screw. This is dictated by the perpendicular orientation of the screw to the fracture plane.
    The distance between the two screws should be equal or greater than the diameter of the screwhead. This is important to prevent splintering of the cortex between the two holes and a subsequent loss of stability. (Note the fracture propagation at the site of the 1st lag screw)
    Occasionally, a 3rd lag screw may be used if required. As this is not a weightbearing bone, there have been no studies to quantify the number of screws necessary for optimal rigidity of stabilisation.

    Closure of periosteum and extensor tendon over the stabilised fractureAfter a thorough lavage, the periosteum is closed over the plate with interrupted monofilament absorbable sutures. I believe this creates a layer underneath the tendon, minimizing the risk of adhesions. The split in the extensor tendon is approximated with monofilament absorbable sutures. I find it useful to check both clinical alignment and passive range of movement at the proximal and distal interphalangeal joints again at this stage before proceeding to final closure of the skin.

    Closure of skin with monofilament nylonSkin is closed with interrupted monofilament nylon sutures.

    A non-adherent soft dressing is applied. The fixation is stable and rigid and therefore does not require protection in a plaster splint.
    The dressing encloses two adjacent fingers to minimise risk of compression to the digital neurovascular bundles.

    The dressing leaves the palm free, thereby allowing better use of the hand while recovering from the procedure.

    Confirm fracture reduction and screw lengths on the X-rays Final X-rays confirm the reduction. The screw lengths are checked and the screws changed if required.
    It is important to ensure that the screw-tip does not protrude far beyond the volar cortex to prevent irritation of the closely adherent flexor sheath. Flexor tendon irritation may cause adhesions and stiffness and may occasionally lead to an attrition rupture.

    Confirming fracture reduction and screw lengths on the X-rays – lateral view

    Post Operative

    The dressings are reduced in the clinic in 48-72 hours. Active mobilization exercises are commenced at this stage along with gentle passive exercises. Special emphasis is needed to mobilise the MCP and PIP joints. A splint is usually not required.
    Sutures are removed in 2 weeks. Gentle routine activities of daily living can be started as soon as comfortable. Rigorous and heavy activity is avoided.
    Radiographs are repeated at 6 weeks. Once the fracture healing is confirmed, aggressive passive exercises can be instituted. Activities of daily living can be increased at this stage. I advise patients against heavy activities for atleast 3 months until the fracture is consolidated.
    Tendon adhesions and stiffness remain the main complication of the procedure. Stern et al (1987 and 1988) confirmed that stiffness was the most common complication of this procedure. An extensor lag at the PIPJ, which is correctible passively, signifies extensor tendon adhesions. Reduced range of active flexion as compared to passive flexion signifies flexor tendon adhesions – and may be due to incorrect screw lengths protruding out of the volar cortex. Tendon adhesions may require tenolysis, which is best delayed for 3 months so as to allow the fracture to fully consolidate.

    Recommended Reading

    The results reported in the literature of phalangeal fractures treated with internal fixation are scarce and contradictory. However, the following may help the reader start on the journey of exploring the efficiency of internal fixation in phalangeal fractures:
    Strickland JW, Steichen JB, Kleinman WB, et al: Phalangeal fractures: factors influencing digital performance, Orthop Rev 11:39-50, 1982.
    One of the early reports on predictive factors of outcome following this injury.
    Shimizu T, Omokawa S, Akahane M, Murata K, Nakano K, Kawamura K, Tanaka Y. Predictors of the postoperative range of finger motion for comminuted periarticular metacarpal and phalangeal fractures treated with a titanium plate. Injury. 2012 Jun 1;43(6):940-5.
    A recent report on predictors of outcome. The authors concluded that increasing age and soft tissue injury were significant predictors of stiffness following internal fixation with plates and screws. The same center, in an earlier publication (2008), concluded that plating of phalangeal fractures was highly efficient in maintain reduction and resulted in reasonable outcomes with few complications.
    Miller LG, Ada L, Crosbie J, Wajon A. Time to commencement of active exercise predicts total active range of motion 6 weeks after proximal phalanx fracture fixation: A retrospective review. Hand Therapy. 2017 Jun;22(2):73-8.
    A retrospective review of 49 fractures showed that the time to commencement of active exercises was the single independent predictor of total range of movement at 6 weeks. The authors concluded that K wire fixation delayed the exercises by atleast 2 weeks, resulting in poorer outcomes than those treated with open reduction and internal fixation.
    Lundin M, Woo E, Hardaway J, Pratt CK, Clarkson JH. The cost of quality: Open reduction and internal fixation techniques versus percutaneous K-wire fixation in the management of extra-articular hand fractures. Journal of Orthopedic Surgery and Rehabilitation. 2017;1(1).
    The authors concluded that that open reduction and internal fixation had better outcomes and fewer complications as compared to percutaneous K wire fixation. However, the numbers of proximal phalangeal fractures included in the study were very small – (8 K wire fixations and 4 internal fixations)
    Johner R, Joerger K, Cordey J, Perren SM. Rigidity of pure lag-screw fixation as a function of screw inclination in an in vitro spiral osteotomy. Clinical orthopaedics and related research. 1983 Sep(178):74-9.
    This article measures the rigidity of lag screw fixation in experimental anatomical tibial models. The authors concluded that the stability offered is strong enough to withstand the pressures of load bearing and can replace plate fixation in spiral fractures.

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