Rotator Cuff Disorders. Hand and Wrist Tendinopathies. Groin Tendon Injuries. Patellar Tendinopathy and Patellar Tendon Rupture. Achilles Tendon Rupture. Achilles Tendinopathy. The Effect of Therapeutic Modalities on Tendinopathy. Anatomical Sites and Presentation. Tendinopathy in the Workplace. The weakest point of tendon healing is 5 to 10 days postoperative, which should be thought out in postoperative management plans.
Flexor tendon injuries are a common event as the tendons lie close to the skin and so are usually the result of either lacerations such as those from knives or glass, from crush injuries and occasionally they can rupture from where they are joined at the bone during contact sports such as football, rugby and wrestling.
Flexor tendon injuries are a challenging problem for orthopaedic surgeons due to three main reasons. Firstly, flexor tendon injuries of the hands are a clinical problem because they cannot heal without surgical treatment, as the two ends need to be surgically brought together for the healing to occur unlike other tendons including the Achilles tendon where it could be placed into plantar flexion to heal. Secondly postoperative management needs to be carefully planned as mobilisation has shown to be essential to prevent adhesions and improve gliding but this can risk rupture.
Lastly due to the unique anatomy of the tendons running through flexor tendon sheaths to function, surgeons need to plan preventing increasing the bulkiness of the tendon through its sheath, which is not always possible from scarring as this affects the functional outcome of the tendon. The symptoms that a patient will present with if the person has a flexor tendon injury are include not being able to bend the finger, pain when bending the finger or localised swelling and open cuts. Tendon injuries can occur in all 5 zones of the hand. As with any hand condition history and physical examination needs to uncover both primary and secondary damage.
Like in any other hand injury, age gender, mechanism and nature of injury, time elapsed are all-important factors that will affect the planning of and decisions made at the time of the repair. The mechanism of injury is vitally important to understand as knowing the level of contamination clean knife versus oily scrap yard machine will indicate preoperative and postoperative care. Furthermore knowing in what position is the finger was during the hyperextension and extension of the finger during injury can give a clue to the findings at surgery so the surgeons can prepare for surgery with the correct approach.
Also looking for previous injuries can be useful to tell the patient the realistic outcomes of surgery. Physical examination needs to include a full examination of both hands and must be carried out systematically. The flexor digitorum superficialis and the flexor digitorium profundus tendons should be tested individually. A normal intact flexor digitorum superficialis is indicated when all the adjacent digits are held with all joints in extension while the patient flexes the finger at the proximal interphalangeal joint.
On the other hand if the middle phalanx is in extension while the patient is directed and able to flex the distal interphalangeal joint, the flexor digitorium profundus tendon has shown to be intact. Fracture should be confirmed using radiographs before surgical intervention, as during surgery these will need to be reduced and fixed before vascular or tendon repair.
Loss of underlying skin and soft tissue needs debridement so this needs to be identified as well as the planning of flaps. Nerve damage is vital to assess, whether it is at the level of the arm, wrist or digit. The ulnar, median and radial nerve needs to be tested by the preference of choice chosen by the surgeon.
Vascular compromise needs to be recorded by the presence or absence of pulses and capillary refill. The ischaemic digit or limb provides an increased level of urgency. The decision to repair a tendon needs to take into account many variables. Primary surgical repair results in better functional outcome compared with secondary tendon repair more than 3 weeks after the primary injury or tendon graft surgery for repairing flexor tendon injuries [ 16 ].
After 3 weeks primary tendon repair will not be possible because of proximal tendon end swelling, tendon contraction and muscle fibrosis. Secondary repair is still acceptable for the injured tendons that cannot be repaired primarily [ 16 ], which may be due to increased risk of infections or excessive loss of soft tissue.
Usually crush or avulsion repair require urgent repair. To date there is no universally accepted gold standard for type of suture material or suture technique used to repair flexor tendon injuries with surgeons using their chosen method to repair such injuries see Fig. However, since then, several surgical approaches have been described. Good exposure is vital to ensure good repair of the tendons it need to enable the surgeon to retrieve the cut tendons, maintain vascularity and not cause contractures and provide access to asses the wound accurately by starting away from the zone of injury and then proceeding to the injury.
The type of incision by the surgeons used does depend on surgeon choice but the most commonly incisions used are the bruner zig-zag and the bunnell incision [ 18 ]. The bruner zig-zag incision avoids the digital neurovascular bundles and stays lateral to the flexion creases and the bunnell is a midlateral incision which avoids the volar surface running in parallel to the digital neurovascular bundles [ 19 ]. Both are usually used as the bunnell avoids disturbing sensation to the volar aspect and the brunner zig-zag avoids vascular compromise.
Strickland stated that the ideal tendon repair should have minimal gapping at the repair site, minimal interference with tendon vascularity, secure suture knots, smooth junction of tendon end and have sufficient strength for healing [ 20 ]. Several studies have tried to investigate the most effective surgical approach. The strength of the repair has shown to be affected by the type, number and location of loops the surgeon uses and the type of suture material [ 21 - 27 ].
Bone and joint structures are repaired first, followed by tendons then neurovascular compartments, which are the most delicate structures and therefore left till then end. After the incision has been made, the next step is tendon retraction. Tendon retraction will be prevented if the vincula is intact.
If the vincula is not intact then a non crushing clamp should be applied to the lacerated end to facilitate the coming together of the ends [ 28 ]. Handling of the tendons should be done with as little trauma as possible to prevent scaring and adhesion. Proximal incision in the flexor sheath can help find the primal tendon when they are not easily visible. The tendon when identified is then fed through the flexor sheath with a flexible tube or a tendon passer. The proximal stump is then secured with a small gauge needle.
The tendon repair should be regarded as a companion of core and peripheral sutures, with both contributing to the strength of the repair [ 29 ]. Many studies have shown that the strength of a flexor tendon repair proportional to the number of sutures crossing the repair site [ 30 ]. Two strand repair techniques were the most commonly used technique in flexor tendon repair up until ten years ago but the discovery that more suture leads to increased strength created a different trend [ 31 , 32 ].
A number of 4-, 6-, 8 -strand techniques are used in clinical practice [ 33 - 35 ]. The first multi-strand was introduced by savage who used 6-strands across the repair site which showed improved gap resistance and forces and able to withstand early motion [ 30 ]. Multi-strand with 4- and 6- core sutures with single-stranded suture have also been investigated which have shown increased gap resistance and fatigue strength compared to 2 strand techniques [ 36 - 40 ].
Eight strand suture has also been compared against 2 six stand savage and 2 strand Kessler and Tajima and was found to have superior strength [ 41 ].
A recent study compared a six strand three figure of eight sutures , four strand locked cruciate repair , and the combined technique a strand cruciate repair using both the figure of eight and cruciate sutures using adult sheep tendons [ 42 ]. Biochemically the combine repair was found to be the strongest regarding both gap and failure using single cyclic tensile failure.
Double stranded sutures have also been researched to perform multi strand techniques. Barrie et al. Multi strands are more demanding and there are potential risks because they need more tendon handling as you pass the needle through many times which could lead to uneven loading of the tendon.
Loop configuration was first described by Pennigton to describe the precise relation of the longitudinal and transverse strands in the grasping and locking modified Kessler repairs [ 44 ]. It has been shown that locking loops improve force and gap resistance compared to grasping loops in flexor tendon repair but the advantage disappear with 3. The amount of tendon that is involved in the repair is determines by the core suture length. The core suture component of a flexor tendon repair has been shown to provide the first resistance to gap formation and repair failure.
With 2- and 4- strand locking and grasping configurations the optimal range of core suture has been shown to be 1. Repairs with 1. Even the location of the knots has shown to change the strength of the tendon repair [ 30 ]. Placement of the knot inside repairs were significantly stronger compared to the knots outside repair after six weeks when test in vivo but ex vivo has shown that placing them outside of the repair on the tendon surface increased the strength of the repair [ 49 ].
The placement of the suture dorsally as also shown to increase the strength of the suture fold and more recently favoured due not risking disturbance of the synovial fluid [ 50 ]. Increasing the suture calibre has shown to increase the force in static testing and fatigue strength in dynamic testing but has not shown to improve the gap resistance.
Barrie et a found that the sue of dacron sutures increased the fatigue strength compared to sutures a 2- 3- fold [ 51 ]. Taras et al. The ideal suture material for flexor tendon repair needs to be easy to use, prevent gap formation but maintain its tensile properties until repair has achieved strength [ 53 ]. Non-absorbable synthesis sutures included monofilament nylon, monofilament polypropylene and braided polyester monofilament nylon have should good biocompatibility are used in repair.
Monofilament polypropylene is mainly used in the peripheral sutures. Higher tensile strength and stiffness was showed with coated braided polyester than monofilament nylon and polypropylene and has shown to maintain its tensile properties at body temperature [ 54 ]. Bioabsorbable sutures have not been used as they have decreased tensile strength half-life and fear of increased tissue reaction and adhesion formation.
The strongest peripheral epitendinous suture methods have been the running lock loop stitch, halsted continuous horizontal mattress suture, cross stitch technique and horizontal mattress infrafibre methods.
This suggests that hydrogels that can be controlled to degrade alongside the release of MSCs will result in the production of de novo tendon tissue that replaces the scaffold and fills the entire defect area. Tendon and ligament: basic science, injury and repair. Estimating lengths of semitendinosus and gracilis tendons by magnetic resonance imaging. Knowledge of the mechanical properties not only contributes to understanding of the tendon function but also provides inputs for computer simulations of the human body [ 28 ]. Fan [ ] demonstrated freehand technique, using a motion sensor, to create a 3D reconstruction of the Achilles tendon. All these subjects had undergone to a chirurgical scarification. The pathogenesis of tendinopathy.
Epitendinous sutures are often referred to peripheral sutures because they grasp not only the epitenon but also the tendon substance and so the peripheral suture has become widely used [ 59 - 62 ]. The strength of the peripheral suture has been found to be strengthened by increasing suture purchase from 1mm to 2mm or 3mm an increasing the number of suture passes as well as deeper suture grasps. It is has bee stated that the annular pulleys from A1 to A5 are vital for the biomechanical flexion as they maintain the tendons close approximation to the joint axis of rotation.
It has been discussed in several reports that A2 and A4 pulleys are critical and therefore should not be disregarded so surgeons should make every decision to preserve these [ 63 ]. L-shaped incisions described by Lister allows retraction of the cruciate pulley and access though the window without damaging the annular pulley.
Partial release of A2 and A4 is performed to facilitate tendon surgery and allow unrestricted tendon gliding [ 64 ]. The A2 plate can be reconstructed using free tendon graft with plantaris or palmaris longus, extensor reticulum, volar plate or fascia lata [ 65 ]. The zone in which the injury occurs can determine the surgical intervention used. Zone I injuries involve the FDP tendons only.
However, since then much research has been done in this area and with improved techniques and suture materials primary repair of the flexors tendon in the digital sheath has replaced the 'no mans land' consensus [ 66 ].