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Anterior cruciate ligament reconstruction using a double-stranded hamstring graft

    Overview

    Learn the Anterior cruciate ligament reconstruction using a double-stranded hamstring graft surgical technique with step by step instructions on OrthOracle. Our e-learning platform contains high resolution images and a certified CME of the Anterior cruciate ligament reconstruction using a double-stranded hamstring graft surgical procedure.
    An ACL reconstruction is indicated to eliminate the pivot shift experienced as the knee dislocates during direction change, be it day to day or during sport. The operation is not intended, or indeed able, to eliminate pain, swelling or stiffness. This must be made clear to the patient for appropriate counselling.
    Timing of the reconstruction is also important. A painful, stiff knee is often best suited to a pre-operative period of high quality physiotherapy as there is a risk of persistent pain and stiffness even after a “successful” ACL reconstruction. There is evidence to show that there is an increased risk of arthrofibrosis if surgery is performed between 2-6 weeks post injury.
    The technique described is an arthroscopic anterior cruciate ligament reconstruction using ipsilateral hamstrings (double-stranded semitendinosus and gracilis).



    Indications

    INDICATIONS:
    It is vital to establish that the patient is suffering from true instability secondary to an ACL rupture. To turn this on its head, a successful ACL reconstruction is aiming to eliminate the pivot shift experienced as the knee dislocates during direction change, be it day to day or during sport. The operation is not intended, or indeed able, to eliminate pain, swelling or stiffness. This must be made clear to the patient for appropriate counselling.
    Timing is also important. A painful, stiff knee is often best suited to a pre-operative period of high quality physiotherapy as there is a risk of persistent pain and stiffness even after a “successful” ACL reconstruction. There is evidence to show that there is an increased risk of arthrofibrosis if surgery is performed between 2-6 weeks post injury.
    SYMPTOMS & ASSESSMENT:
    Instability on direction change (pivoting) is the overriding symptom. The patient may develop swelling and pain post-dislocation.
    Symptoms of locking and pain may be attributable to concurrent injuries such as meniscal tears and bone oedema.
    Thorough knee assessment is vital. In excess of 60% of knees will have a concurrent knee injury. Multi-ligament injuries must be carefully assessed. Neurovascular injury must be ruled out.
    ACL specific tests:
    Lachman – specificity 95% sensitivity 80-99% – test of choice
    Anterior drawer – specificity 75-95%; specificity 22-41% – risk of false positive
    Pivot shift – specificity 98%; sensitivity 84-98.4% (35% in the awake patient)
    INVESTIGATION:
    X-ray: I would strongly advocate an x-ray for an acutely injured knee to rule out fracture. Furthermore a Segund fracture, a tiny bone fragment visible adjacent to the lateral joint line, is pathognomonic of an ACL injury
    MRI: this is the investigation of choice for ligament injury in the knee, not least to look for concurrent injuries which are drowned out by the “noise” of an ACL injury. A reparable meniscal tear or a multiligamentous injury may influence the decision for early surgical intervention.
    OPERATIVE ALTERNATIVES:
    Combined ligament reconstructions
    Meniscal surgery
    Extra-articular ligament reconstruction (e.g. Mackintosh) especially in the revision setting
    NON-OPERATIVE ALTERNATIVES:
    Physiotherapy – this is a vital tool for the management of an ACL deficient knee. A successful regime post injury can avoid surgery. Pre-habilitating a painful stiff swollen knee is imperative before considering reconstruction.
    CONTRAINDICATIONS:
    Active infection
    No demonstrable functional instability
    Relative contraindications:
    pain
    stiffness
    significant OA

    Setup

    High thigh tourniquet
    Pre-operative antibiotics (be aware of patient allergies)
    Side-support
    Foot plate / sandbag
    Arthroscopy stack
    Shaved operative site
    “Plan B” options:
    consider preparation of contralateral leg for hamstring harvest
    patellar tendon harvest equipment
    supporting implants eg xtendobutton for inadvertent blow out of lateral femoral cortex; small fragment screws and washers or bone staples for secondary tibial fixation

    Operation – 1

    Knee positioning with a side bolster, foot plate and sand bag.
    Ensure that the tourniquet is as high as possible to avoid the passing pin puncturing the cuff as it emerges from the thigh. This also allows for maximal deep flexion which is important when drilling the femoral tunnel.
    I use a large sandbag against a L-shaped bracket for the foot. With the sole of the foot resting on the sandbag the knee is at 90 degrees, as in this image. The knee can be further flexed to trap the toes against the sandbag to allow deeper flexion (see next slide).

    A deeper flexed resting position can be achieved by trapping the toes against the sandbag.
    This is particularly useful during drilling of the femoral tunnel via the anteromedial (AM) portal.

    The patella, patella tendon, tibial tuberosity, joint line and pes anserinus skin incision markings are established.For orientation it is vital to identify (as marked):
    medial edge of patellar tendon
    tibial tuberosity
    medial joint line
    pes anserinus – this is three fingerbreaths below the medial joint line

    The incision for the hamstring harvest is over the pes anserinusThe leg is prepared with skin preparation and an arthroscopy drape. The tourniquet is then inflated.
    Provided that ACL rupture is confirmed through a positive MRI scan and a positive pivot shift on table, proceed to hamstring harvest. If there is any doubt about the integrity of the ACL then perform a diagnostic arthroscopy first.
    A longitudinal incision is made over the pre-determined site of the pes anserinus. I prefer a vertical incision to allow easier extension in order to find the pes anserinus and, later, for accurate outside-in tibial drilling. Sharp dissection down onto the bursa is preferable to blunt dissection as the fat layer tends to fibrillate if spread rather than cut.
    There is a risk of damage to a branch or the main trunk of the saphenous nerve. Patients should be counselled of this risk and post-operative numbness.

    The gracilis and semitendinosus tendons can be identified by rolling them under your finger against the postero-medial bony edge of the tibia.The overlying bursa is elevated away from the gracilis tendon with a pair of toothed forceps. Using a closed pair of dissecting scissors the ends are punctured through the bursa above the gracilis tendon, exposing the shiny fibres of the superficial MCL beneath. The tendons are found distal to the puncture hole and often against the overlying bursa. It is imperative to avoid inadvertent damage to the gracilis tendon if extending the incision in the bursa proximally.

    The hamstring tendons are identified within the sartorial bursaOnce the bursa is opened a langenbeck retractor can to placed to lift the bursa away from the tibia to give a good view of the tendons arising from the pes anserinus.
    The gracilis tendon is isolated with a tendon hook and pulled out of the wound. Occasionally vinculae need to be released to allow easy retraction of the tendon.

    The gracilis is harvested first.I find it best to hook my finger under the tendon to bring it out of the wound. If the tendon is free and ready to be stripped this should be easy and springy. It can be further facilitated by increasing knee flexion. Before progressing to applying the tendon harvester / stripper the surgeon must be confident that the tendon is not tethered as this could lead to deviation of the cutting edge and inadvertent amputation which leads to a shorter that expected graft.

    The tendon harvester is applied to the tendon
    Ensure that it runs freely up the tendon.

    The harvester is pushed up the tendon
    The device pictured can be locked over the tendon, run up the tendon and cut at a pre-determined length – ideally a minimum of 20-22cm. The technique is to apply a counter-pull with ones finger whilst running the stripper into the thigh towards the groin with gentle pressure. It is my preference to take as much tendon as possible rather than using the cut mechanism, to allow for potential “tripling” of the graft if thin.

    Retrieving the semitendinosus tendon is aided by pulling on the harvested gracilis tendon.
    Next the semitendinosus (ST) tendon can be hooked. This tendon is particular is tethered by vinculae arising from its inferior edge and running towards medial head of gastrocnemius. Care must be taken too ensure that all of these are released before attempting the harvest the tendon to avoid amputation as mentioned.

    The muscle is stripped off both tendon using a ruler or a pair of dissecting scissors to leave only true tendon graft.If this is not done then the graft diameter will be over measured leading to oversized bone tunnels.

    The tendons are released at the pes anserinus and converted to two distinct tendons.The tendon ends are then “whipstitched” or “baseball stitched” using heavy suture. I prefer to use different colours for each tendon to allow for equal tensioning at the end of the operation (e.g. purple suture for both ends of gracilis and green suture for semitendinosus).

    A sizing block is used to assess the graft diameter The tendons are laid side by side and folded in the middle over a suture to “double” each tendon. This is then passed through the sizing block to establish the diameter of the graft. Ideally this should be between 7mm to 10mm in diameter (in this case 8.5mm).

    Ensure that the graft is trialled through many sizing slots. The graft should pass through snugly down to 0.5mm so long as there are half-size reamers available.Once the graft size is establish protect the graft on the back table with a saline soaked gauze.
    Tips:
    1) some surgeons include soluble antibiotic in the saline to soak into the gauze to reduce infection risk
    2) pulling the doubled graft into a sizing collar of a half-size too small and stop the graft from absorbing saline and expanding. This eases passage of the graft into the bony tunnels.

    The anterograde-lateral viewing portal is made in a horizontal fashion.Next the operation proceeds to the arthroscopic stage. I prefer to make horizontal arthroscopy incision to avoid inadvertent damage to the meniscii, however some surgeons prefer vertical incisions to allow extension as required. The lateral portal is the viewing portal. The medial portal positioning requires special attention as it is used to drill the femoral tunnel. Occasionally two medial portals are required to allow for meniscal surgery and tunnel drilling which often require different angles of approach.

    Full arthroscopic assessment is vitalThe operation then proceeds with the following overview steps:
    arthroscopic assessment of the entire joint
    meniscal / articular cartilage surgery
    clearing of notch / remnant ACL
    establishment and preparation of the femoral tunnel via the medial / additional antero-medial (AM) portal
    establishment and preparation of the tibial tunnel
    graft preparation
    graft passage
    femoral fixation
    graft tensioning and tibial fixation

    Assessment for a potential ramp lesion in the posteromedial capsulePLEASE NOTE THAT THE ARTHROSCOPIC IMAGES THAT FOLLOW RELATE TO A RIGHT KNEE
    As part of a thorough examination of the joint, especially in the case of ACL reconstruction, it is important to have a good view of the posterior horn of the medial meniscus through the notch. Ramp lesions are frequently encountered and repair is recommended. In this case there is no ramp lesion (separation of the meniscus from the capsule).

    The stump of the ACL is found in the notch and complete disruption is confirmed.In this case the ACL is completely detached from the femoral insertion and “fallen” onto the PCL. Probing confirms a non-functional ACL remnant. Using the arthroscopic shaver the remnant can be partially or fully excised. There is increasing interest in retaining some ACL remnant especially on the tibial side through which to pull the hamstring graft.

    The medial wall of the lateral femoral condyle is cleared to give an excellent view and hence a clear passage for the graft.Soft-tissue is excised to gain a good view of the posterior edge to avoid inadvertent misplacement of the femoral tunnel. Soft-tissue clearance can be performed with a combination of shaver, radio-frequency ablation and hand-held curettes. There may be some biological advantage however to try to retain some native soft tissue so long as this does not compromise view and graft passage.

    The centre of the planned femoral tunnel is marked using a microfracture awl.There are many descriptions for the ideal placement of this tunnel. My preference is to create as near anatomical tunnel as possible. The awl tip is used to mark a pilot hole just behind the bifurcate ridge, below the intercondylar ridge at roughly the 10 o’clock (right knee) position. However the clock face technique can be influenced by the variable length of the notch and the knee flexion angle and so should be used with caution. As I use a single bundle technique this is a good compromise to create a graft that will function to stabilise rotational instability and eliminate a pivot shift. If the femoral tunnel drifts to high in the notch patients often continue to have rotational instability. However too low on the wall leads to graft impingement on the lateral tibial eminence and risks failure. The aim to avoid impingement on the roof, PCL and the floor throughout a range of motion.

    The pilot hole created by the awl is checked to confirm ideal placement and used as the starting point for a 2.4mm drill tipped passing pin guide wire. With the tip of the wire in the pilot hole the knee is carefully hyperflexed for two reasons:
    this increases the potential length of the tunnel
    avoids damage to the common peroneal nerve
    improves the angle for drilling

    In this image the tip of the guidewire can be seen advanced to a position midway up the lateral thigh and a good handbreadth anterior to the biceps femoris tendon and hence away from the nerve.One tip is to keep your drilling hand horizontal to the floor and as midline as possible. This will create a long safe femoral tunnel.

    The wire is then overdrilled using a 4.5mm cannulated drill through the far cortex (inside to out).This creates a tunnel wide enough to allow passage of the femoral fixation device in the vertical position but too narrow to allow the button to be pulled back down the tunnel once in its horizontal position.

    The drill and wire are removed and the length of the tunnel is measured using a depth gauge.Care must be taken that the full length of the tunnel is measured as this is a blind measurement. If in doubt image intensification can be used. Be aware that depth of field can mislead the measurement. Take time to double check this (in this case 46mm).

    The 2.4mm passing pin is reinserted free hand and overdrilled using the corresponding 8.5mm reamer (to match he diameter of the graft). In this case I am using a 20mm continues loop endobutton. This requires a turning distance of 10mm, which means that the metal button must emerge from that lateral cortex of the femur by 10mm in order for it to be swivelled from the vertical passing position to the horizontal fixation position. In order to allow room at the top of the tunnel for this manoeuvre the 8.5mm reamer is drilled to a depth of 36mm (10mm short of its full length). Once the button has been turned and pulled up against the lateral cortex the tunnel will contain 20mm of the loop and 26mm of hamstring graft. It is imperative to make this calculation BEFORE drilling with the reamer.

    Operation – 2

    A shaver is then passed into the tunnel to clear all bony debris as this can foreshorten the tunnel on passing the graft.

    The knee is returned to 90deg flexion and the femoral tunnel is checked to ensure that it is not blocked by the PCL.

    The tibial aiming jig is set to 45 degrees (or greater if a longer tunnel is required). Attention now turns to placement of the tibial tunnel. In the image the tip of the aimer is probing the posterior edge of the anterior horn of the lateral meniscus. This is used as the first reference point.

    The ideal centre of the ACL tibial tunnel is carefully identified using the anatomical markers.In this image the tip is indicating the midpoint of the medial tibial eminence. This is the second reference point. An imaginary line is drawn between the first and second reference points. At its midpoint, within the substance of the remnant of the ACL stump, is the centre of the tibial tunnel.

    The tip of the guide is placed and fixed against the tibia externallyThis particular tibial aiming guide is an elbow aimer (tip aimers are also available) so the surgeon must calculate the point at which the tip of the guidewire will emerge to be at the established midpoint of the intended tibial tunnel.

    The 2.4mm passing pin guidewire is drill via the hamstring harvest wound on the anteromedial tibia just anterior to the superficial MCL. The device allows the length of the tunnel to be read prior to drilling and ideally should be longer than 40mm.

    Tibial tunnel is created using the appropriate reamer.Once the wire is in a satisfactory position the 8.5mm reamer is drill under direct vision outside-in.

    Direct vision is required when the reamer enters the knee joint.The reamer is advanced cautiously to avoid overreaming and damage to the opposite femoral condyle (the passing pin will often start spinning as the reamer approaches the tibial surface cortex).

    The tibial tunnel is cleared of bone debris and both aperatures are cleared of overhanging soft tissue to avoid snagging the graft.

    The femoral fixation is an endobutton with a fixed loop into which the graft is passed.With the bony tunnels completed the graft is now prepared by looping both strands over the endobutton loop to create 4 equal strands of graft. The graft is marked at two points:
    the distance from the leading end of the graft to when it reaches the end of the 8.5mm step tunnel in the femoral tunnel (in this case 36mm). This is the indicator for the endobutton being outside the femoral tunnel and so can be flipped from its vertical position to its horizontal position)
    the distance from the leading end of the graft to its resting position once the endobutton is snugged up against the lateral femoral cortex (in this case 26mm).

    A shuttle suture loop is therefore required to pass the threads of the endobutton up the tunnels.By drilling both tunnels independently of each other this means that they are not necessarily in line or parallel. A loop of a strong smooth suture is passed through the eyelet of the passing pin. The passing pin is then passed across the knee joint and up the femoral tunnel free hand via the AM portal, whilst the surgeon keeps hold of the looped end of suture.

    The pin is pushed through the thigh as it emerges from the femoral tunnel again with the knee in deep flexion to avoid damage to the common peroneal nerve.

    The free ends of the suture are collected by the assistant. Note the loop outside the AM portal.

    An arthroscopic grasper is passed up the tibial tunnel and collects the suture, pulling the looped end down the tibial tunnel. Now the shuttle suture runs from the looped end at the tibial tunnel, across the knee and up the femoral tunnel.

    The sutures for the endobutton are then passed into the shuttle suture loop, pulled through the tunnels and collected by the assistant. The surgeon watches the sutures (in this case white and green) cross from the tibial tunnel and up the femoral tunnel. The assistant then pulls the graft up the tunnels by leading with the white suture to maintain the endobutton in the vertical position.

    The graft progresses initially through the tibial tunnel into the knee under direct vision.This image shows the endobutton crossing the knee in the vertical position as it enters the femoral tunnel.

    The graft is pulled up to the second line to indicate that it has reached maximum depth in the femoral tunnel.At this stage the endobutton has emerged from the lateral cortex, when it is toggled by pulling on the green suture. The graft is then pulled back from the tibial end until the endobutton no longer toggles as it abuts the lateral cortex. The graft will have now come back to the first line as shown in the image. Femoral fixation is now completed.

    A flexible guidewire for the tibial interference screw is passed up the tibial tunnel until it emerges alongside the graft.The guide wire should be passed when the knee is in the correct position for graft tensioning (my preference is 30 degrees of flexion), as bending the knee later can bend the wire and cause it to get stuck.

    A knot is tied in the emerging whipstitch sutures to allow for equal tensioning of the four strands.I currently use a PEEK interference screw which I choose to be 1-1.5mm larger than the tunnel (in this case 10mm) and 30-35mm depending on the length of the tibial tunnel measured off the tibial aiming device in step 30 above.

    The knee is held into around 30 degrees of flexion.Although not captured in this image I will often pass a toffee mallet through the loop of sutures and rest my knuckles against the tibial to avoid forward subluxation of the tibia whilst advancing the interference screw.

    The screw must be at the tibial cortex but not too prominent as this can be felt by the patient when kneeling.However this is a fine balance as cortical hold is advantageous. The guidewire is removed and the knee is cycled to ensure no loss of extension or flexion due to an inadvertently significantly anisometric graft.
    The knee can be tested with a lachman and a pivot shift to ensure that both have been satisfactorily eliminated. Only if this is the case is the graft fixation over.

    The graft is tested for tension using a probe.It is also observed through range to ensure there is no PCL, lateral wall or roof impingement. It is vital also to check that the interference screw is not emerging from the tibial tunnel. The knee is checked again and washed of all debris. All the fluid is removed from the joint before closure.

    The knee wounds are closed including the portals as drilling tunnels creates a significant haemarthrosis.

    The hamstring harvest site and the knee joint are infiltrated with 0.75% ropivacaine due to its low chondrotoxicity.
    The skin is closed with skin staples. A wool and crepe bandage is applied before releasing the tourniquet. Caution is taken to avoid sudden hyperextension of the knee and damaging the graft.
    A knee brace fixed from 0-90degrees is applied.

    Post operative xrays confirm the correct deployment of the endobutton and tunnels.

    Operation – 3

    Post operative xrays confirm the correct deployment of the endobutton and tunnels.

    Post Operative

    The patient is prescribed compression stockings until fully weight bearing. Skin staples are removed at 14 days post-op.
    There are a large number of ACL rehabilitation programmes available all with the aim of returning the patient to full function and to achieve the best possible outcome with a knee stable enough to allow them to return to pre-injury levels of sport. Any perceived instability has a significantly debilitating affect of their outcome. The operation is only the beginning.
    It is my preference to brace knees post reconstruction for 4 weeks. I will increase this to 6 weeks if there has been a combined meniscal repair. I will exclude multiligament protocols from this discussion. I also keep my patients non-weight bearing for 2 weeks and avoiding significant cyclical loading of the knee for 6 weeks. I believe that it is very unusual for young fit patients with hamstring grafts not to achieve full range of motion, including extension, even when taking the first 4-6 weeks slowly. This is an observation I made with those patients who I braced for their meniscal repairs. In fact anecdotally I felt that this group had firmly negative lachmans at 6 months more consistently compared to those who were not braced.
    The two weeks of non-weight bearing and 6 weeks of deliberate cyclical loading avoidance helps the soft-tissues settle and good biological fixation of the graft to the bony tunnels. It enforces the overzealous patient and physio to slow down early on!
    The aims of a good rehabilitation programme include:
    swelling and pain control
    range of movement recovery
    gait retraining
    balanced strength recovery
    proprioception
    plyometry
    speed of acceleration and deceleration
    agility
    sports specific retraining
    psychological support
    I would encourage a good relationship with your rehabilitation team and regular review of patients. Never force a patient to return to full sport if they themselves do not feel ready. This can range form 6 months to 18 months so do not force the issue. Having a significant knee injury can be very psychologically damaging and returning to that setting can take time. If there is a reluctance the surgeon must establish whether there is still some subtle instability in the knee. There are some good online psychological testing questionnaires available online and these can be helpful when formulating a return to sport protocol.

    Recommended Reading

    There has always been a healthy debate about the optimum graft for ACL reconstruction. The options include:
    autologous hamstring graft – ispilateral / contralateral / double-stranded or more
    autologous patellar tendon graft
    autologous quadriceps tendon graft
    allografts
    synthetic grafts
    Multiple publications have lauded the benefits of each option. Historically synthetic graft have performed badly and fallen out of favour. Allograft survivorship has shown a significant correlation to the sterilisation technique employed, with irradiated grafts performing poorly against bio-cleansed grafts. The morbidity of patellar tendon harvest is outweighed by its bone-to-bone tunnel fixation and stiffness. Hamstring grafts have lower morbidity but possibly rely more heavily on biological fixation of a soft tissue scaffold to a bony interface. There continues to be a lot of healthy debate in this area. The essential choice a surgeon must make is to excel at a chosen technique or two. Take a healthy interest in rehabilitation and have a strong dialogue with the rehabilitation team.
    The integrity of the menisci at the time of ACL reconstruction appears to be very important in reducing knee laxity and decreasing the risk of graft failure. A paper from 2015 showed that ACL reconstruction survivorship at 2 years with intact menisci to be 94.5%, often quoted as the success rate of the procedure. However with either medial or lateral meniscal deficiency this dropped to 69%. Therefore without intact meniscii the patient’s potential failure rate increases by 4.9 times compared to intact or repaired meniscii. Meniscal integrity predicts laxity of anterior cruciate ligament reconstruction. Robb C, Kempshall P, Getgood A, Standell H, Sprowson A, Thompson P, Spalding T. Knee Surg Sports Traumatol Arthrosc. 2015 Dec;23(12):3683-90.
    It stands to reason therefore that a surgeon who undertakes ACL reconstruction should be accomplished in repairing menisci whenever possible.

    Reference

    • orthoracle.com

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