University of Iowa – sports medicine conference – Dr. Ian alexander
December 8th, 2005
2 Tendon disorders of the ankle and hindfoot..
2.1 Etiology, pathophysiology and pathoanatomy.
2.2 Clinical presentation.
2.4 Images, classification and measurement.
2.5 Treatment – non operative.
2.6 Treatment – surgical decision making.
2.7 Treatment – surgical techniques.
2.8 Pearls and pitfalls.
3 Pes planus.
3.1 Etiology, pathophysiology and pathoanatomy.
3.2 Clinical presentation.
3.4 Images, classification and measurement.
3.5 Treatment – non operative.
3.6 Treatment – surgical decision making.
3.7 Treatment – surgical techniques.
3.8 Pearls and pitfalls.
¨ Tendon disorder of the ankle and hindfoot are generally thought to be caused in most cases by either acute trauma or chronic over use.
¨ Acute trauma consists either
· Complete or partial disruption of a tendon due to the sudden application of force or
· Laceration of a tendon with a sharp penetrating object.
¨ Chronic over use injuries result in cumulative microtrauma to the tendon that without sufficient time to repair leads to degenerative changes in the tendon referred to a tendinopathy. Histological changes of tendinopathy include non-inflammatory intra-tendinous collagen degeneration, fiber disorientation and thinning, hypercellularity, scattered vascular ingrowth, and increased interfibullar glycosaminoglycans. Inflammatory cells and other signs of inflammation are notably absent. Factors that contribute to the development of tendinopathy include:
· Biomechanical abnormalities that increase the intrinsic tendon stresses. A good example of this is the development of tibialis posterior tendinosis in patients with pes planus where the tibialis posterior repetitively attempts to stabilize the collapsing arch in midstance. These mechanical abnormalities may not only increase absolute stress on the tendon but may also produce abnormal load distribution within the tendon that creates intra-fibril stresses and friction that induces local fiber damage.
· Other factors that may contribute to the process include: patient weight, patient activity (excessive activity or stress), tendon vascularity (water shed areas may be more prone to degeneration), joint instability, muscle dysfunction or contracture, and changes in training technique, surfaces or shoe wear.
· The damage caused by overuse injuries may be mediated by free radicals on reperfusion of ischemic tissue, and other local phenomena such as tissue hypoxia and hyperemia or impaired tenocyte apoptosis.
¨ Tendinopathy is a global term that covers a number of tendon pathologies that can be seen in isolation or in combination. These include:
· Tendinopathy of the body of the tendon (often referred to as tendinosis)
· Tendinopathy of the surrounding tissues (peritendinitis)
· Pan tendinopathy (involvement of the body and surrounding tissue)
· Insertional tendinopathy
· Tendon rupture
· Juxta-tendinous bursitis (e.g. retrocalcaneal bursitis)
· Tendinopathy with tendon subluxation
¨ Pain that is accentuated by activity and usually acute initially with start up after rest is characteristic of tendinopathy. In athletes the pain is initially worse at the beginning and end of training but eventually is continuous during activity.
¨ In sedentary patients gradual onset of medial or lateral ankle pain or pain in the Achilles tendon area without precipitating injury is due to tendinopathy until proven otherwise.
¨ If patients with tendinopathy are asked where their pain is located they will often move their hand up and down the limb along the course of the involved tendon. This is very different from patients with arthrosis that move their hands across the foot in line with the arthritic articulations.
¨ With rupture there is sudden pain but often the patient continues to be able to ambulate, albeit with some pain, but weakness is often noticeable.
¨ In cases where rupture follows a long period of painful tendinosis with attritional lengthening of the tendon the patient may not even appreciate that complete rupture has occurred and, in these cases, complete rupture may even be associated with some symptomatic relief.
¨ Patients with medial ankle pain due to tibialis posterior tendinosis may have noted progressive flattening of their longitudinal arch and “turning out” of their foot. In severe cases lateral ankle pain may ensue as the laterally displaced calcaneous begins to impinge against the distal fibula.
¨ In patients with peroneal tendon subluxation as the cause of their tendinopathy they may volunteer that they experience a clicking sensation over the distal fibula.
¨ Common physical findings of tendinopathies include:
· Tenderness along the course of the tendon that is clearly accentuate by resisted contraction of the contiguous muscle belly.
· Swelling along the course of the tendon with loss of definition of the tendon margin especially adjacent concavities such as that behind the malleolar.
· Pain with passive stretch of the tendon (e.g. dorsiflexion an eversion of the foot will induce pain in patients with peroneus longus tendinosis)
· Thickening and/or nodularity of the tendon body.
· Weakness or functional loss that may be due to painful inhibition or tendon attrition or lengthening (e.g. in tibialis posterior tendinosis the patient is unable to single heel rise on the involved side and with double heel rise the degree of heel inversion is less compared to the normal side).
¨ Achilles tendinopathy is a spectrum of conditions with variable exam findings.
· Tendinosis of the body – mid substance tenderness proximal to the insertion that may be associated with diffuse tendon enlargement and/or nodular thickening.
· Tendinopathy of the surrounding tissues – palpable thickening of the peritenon but clinically differentiating this from tendinosis is difficult and the differentiation is most easily made on MRI.
· Insertional tendinopathy – acute tenderness and tendon thickening primarily localized to the tendon insertion and just proximal to it.
· Rupture – palpable defect is present usually at the musculotendinous junction but may be distal if avulsion occurs at the calcaneal insertion, the latter being unusual in healthy individuals. The classic physical finding of rupture is a Thompson squeeze test that demonstrates a lack of passive ankle plantar flexion with squeezing the calf.
· Retrocalcaneal bursitis – is characterized by bursal prominence (swelling) to the medial and lateral sides of the tendon. It is often associated with insertional Achilles tendinosis but if an isolated problem tenderness will be absence directly over the tendon and maximal just anterior to the tendon margins at the level of the top of the os calcis.
¨ Tibialis posterior tendinosis > rupture
· In early stages swelling and tenderness is evident along the course of the tendon posterior and inferior to the medial malleolus.
· In the later stages as the tendon lengthens due to attrition the tibialis posterior becomes a less effective midstance stabilizer of the foot and the longitudinal arch collapses progressively.
· Two special tests help bring out this pathology – the single and double heel rises tests. These tests are performed this the patient facing and standing approximately a foot back from and with hand on a flat wall without any hand holds. In this position, ensuring that the knee is kept fully extended, the patient is asked to raise both heels off the ground. Decreased heel inversion will be evident on the involved side. Subsequently the patient is asked to single heel raise on each foot. On the symptomatic side this is not possible. It is important to realize that other pathologies can cause a similar effect especially with the single heel rise test. The double heel rise test is more specific as only conditions that limit subtalar joint mobility will give a false positive whereas any condition causing weight bearing foot pain may cause a false positive single heel rise.
¨ Peroneal tendinosis > rupture
· In addition to testing eversion strength and for tenderness along the peroneals with eversion the examiner should place a digit over the posterolateral distal fibula to check for the snapping of a dislocating tendon.
· Peroneus longus integrity is checked by resisting plantar flexion of the first metatarsal and in the case of tendinosis there may be accentuated tenderness not only in the cuboidal groove but also across the plantar aspect of the foot between the groove and the first metatarsal base. In the absence of a neurological deficit marked weakness of first ray plantar flexion is highly suggestive of peroneus longus rupture.
¨ Tibialis anterior tendinosis > rupture
· Tibialis anterior tendonitis is a relatively rare entity but is most easily diagnose by the presence of tenderness along the tendon with resisted ankle dorsiflexion.
· Tibialis anterior rupture is also unusual and is frequently missed due to the fact that other ankle dorsiflexors minimize the functional deficit. The classic finding is fusiform swelling over the anteromedial ankle where the bulbous end of the ruptured tendon becomes lodged beneath the superior extensor retinaculum.
¨ Flexor Hallucis Longus tendonitis and stenosing tenosynovitis
· At the back of the ankle joint the FHL passes through a narrow fibro-osseous tunnel as it leaves the leg to enter the foot.
· In cases of tendonitis the patient, often a dancer, complains of posteromedial ankle pain and tenderness is present in the same region. Pain may be precipitated by forced ankle plantar flexion.
· The formation of a nodule on the tendon in long standing cases may result in triggering of the hallux as the enlarged tendon passes through the tunnel.
¨ Plain radiographs – are usually of little help in the evaluation of the tendinopathy with some notable exceptions:
· Calcific insertional Achilles tendinosis – bone emanating from the middle of the posterior calcaneous and extending proximally is common in long standing cases of insertional Achilles tendinosis.
· Peroneus longus calcification – elongated calcification in the cuboidal groove, most apparent on the oblique view of the foot, represents calcium deposition in the peroneus longus where it is most often affected by tendinosis where it makes an acute turn from its course in the lateral foot to traverse the deep plantar planes to reach it primary insertion on the 1st MT base.
· Rupture of the peroneus longus in or beyond the groove may be associated with proximal migration of the calcified tendon with appearance of the calcification over the lateral calcaneal wall when the calcified portion of tendon hangs up on the inferior extensor retinaculum at the peroneal tubercle or behind the ankle if it passes this isthmus.
· Haglund’s deformity is an abnormal prominence of the posterior superior margin of the calcaneal tuberosity above the insertion of the Achilles tendon. It is thought to contribute to the development of insertional Achilles tendinosis due to mechanical irritation.
· In adult acquired flatfoot due to tibialis posterior tendon attrition the standing lateral radiographs shows loss of calcaneal angle of inclination and reversal of the talar-first metatarsal angle and on the standing AP divergence of the talar head and anterior calcaneous and lateral positioning of the navicular on the talar head.
¨ MRI is very helpful in evaluating tendinopathy
· In tendinosis the MRI findings include increased intra-tendinous signal intensity especially on the T2 weighted images, thickening of the tendon and peritendinous fluid.
· Complete rupture will show absence of the tendon in it usual locations distally and enlargement and disorganization of the tendon proximal to the rupture.
· Surgical intervention should be based mostly on clinical assessment, as false positive and negative MRI studies are not uncommon.
· Ultrasonography has been advocated by many as a means of evaluating tendinopathy but the success of the technique is very operator dependent and does not provide information with the clarity of an MRI.
¨ Non-operative treatment of tendinopathy follows the same principles regardless of the particular tendon involved:
· Early cases – limitation of symptom precipitating activities, prolonged non-painful stretching to improve flexibility, correction of biomechanical problems that are causing the problem and local thermal therapy
· Advanced cases – sustained tendon rest with immobilization in a cast or brace.
¨ Achilles tendinosis – body or insertion
· Early – gentle stretching, heel lift, ice.
· Advanced - Immobilization in cast or short leg walking boot for a sustained period followed by gradual weaning as clinical signs and symptom abate at bimonthly evaluations. In cases where patient must continue to work and this is not possible with a boot a fixed ankle AFO can be tried but this must be fabricated to avoid pressure on the tendon.
¨ Achilles rupture
· In a non-athlete non-operative management of Achilles rupture is a very acceptable method of treatment. Casting in a plantar flexed position with gradual dorsiflexion in serial casts after 4 to 6 weeks is the classic approach. Functional weight bearing with the ankle in equines is an alternative that has yielded better results in this non-operative group.
· The current consensus is that Achilles ruptures in athletes should be treated surgically.
¨ Tibialis posterior tendinosis
· Early – ice, anti-inflammatory, and a longitudinal arch support particularly in patients with pes planus
· Late – if very acute cast of settle symptoms and during the casting phase fabricate an orthosis that will allow ankle motion but restrict hindfoot inversion and eversion. Once signs and symptoms are controlled the cast is removed and the patient is placed in the short articulated AFO. Absolute compliance with wearing the brace whenever weight bearing is essential to achieve a positive result. The patient can be slowly weaned from the brace only after months of continuous use and, initially this should be into a supportive athletic shoe with a custom orthoses.
¨ Peroneal tendinosis
· Early and late – in patients with forefoot valgus and a compensatory hindfoot varus causing peroneal tendinosis biomechanics correcting orthoses that post the lateral forefoot and heel can be quite helpful in reducing tendon stresses and pain. If the hindfoot is neutral foot orthoses are of little help and a device to control hindfoot inversion and eversion is indicated. The short articulated AFO described above is effective in many cases.
¨ The indication for surgery in each of these cases is failure of the non-operative treatment outlined above over a period of three to six months.
¨ Achilles tendinopathy treatment depends on the type of involvement.
· Body tendinosis – response to surgical debridement of the degenerative portions of the tendon is often gratifying
· Insertional tendinosis – although resection of a wedge of bone from the posterior superior calcaneal tuberosity and local debridement of degenerative tendon and calcification is widely employed in the treatment of insertional tendinosis the outcomes of surgery in advanced cases with extensive degeneration are less than satisfactory. Decompression and debridement is most helpful to patients with partial tendon involvement. Patients with advanced disease, clinically and on MRI, or that have failed debridement, are best treated with resection of the distal involved tendon and reconstruction with a FHL (flexor hallucis longus) transfer.
· Peritendinopathy – can be treated with superficial debridement.
· Rupture – is treated surgically in patients with an interest is continue participation in competitive sports that involve rapid acceleration and cutting as these patient are more prone to re-rupture if treated non-operatively.
¨ Tibialis posterior tendinosis (adult acquired flatfoot) – see the Pes Planus section
¨ Peroneal tendinosis
· Surgical treatment depends on zone of involvement. The 3 zones described are Zone A is perifibular and deep to the superior peroneal retinaculum, Zone B which is in the region of the peroneal tubercle of the calcaneous and deep to the inferior peroneal retinaculum and Zone C which is in the cuboidal groove.
· Zone A problems relate to the subluxation of the peroneal tendons and the resulting tendon irritation. Problems in this zone occur more frequently in patients with a peroneus brevis muscle belly that extends abnormally distally or have accessory peroneal muscles. Treatment of problems in Zone A consist of tendon debridement and repair if needed, resection of excessively distal or anomalous muscle tissue, and in most cases the stabilization of the tendons.
· Zone B problems in some cases relate to stenosis of the tendons at the peroneal tubercle. Occasionally a ridge of bone that passes transversely under the tendons, at the level of the tubercle, will abrade the tendon.
· Zone C problems apply primarily to the peroneus longus as it passes through the cuboidal groove.
· Surgical management of Zone A injuries consists of tendon stabilization, Zone B of decompression, elimination of bony ridges, and tendon debridement and Zone C problems of tendon debridement, excision of calcific deposits and repair of the tendon.
¨ FHL tenosynovitis
· Treatment of persistent pain or triggering of the hallux is a longitudinal opening of the fibro-osseous tunnel and a tenosynovectomy or tenolysis as indicted.
¨ Tibialis posterior tendinopathy – For the management of tibialis posterior tendon related pathology see the surgical techniques section of Pes Planus.
¨ Achilles tendinopathy – debridement of tendon body
· A longitudinal incision is made over the tendon and the tendon is exposed. All amorphous degenerative tendon is excised leaving and fiber that appear intact.
· Using an absorbable suture run the closure of the inner tendon and then continue the running closure along the surface.
· If there are no normal appearing fibers reconstruction with the FHL is the only option. (see below)
· Post op care consist of protection in a walking boot for a minimum of 6 weeks followed by a progressive strengthening program
¨ Insertional Achilles tendinopathy – debridement of the insertion
· Make a vertical incision directly over the center of the Achilles tendon at the insertion and mobilize the soft tissues to the side to allow visualization of the posterior superior tuberosity of the calcaneous. From the medial or lateral side free up the margin of the tendon down to the point of the transverse insertion into the calcaneous.
· Using a microsagittal saw or and osteotome resect the posterior superior portion of the calcaneous down to the tendon insertion.
· With sharp dissection excise all degenerative possible leaving normal fibers undisturbed. By palpation or with vertical incisions in the tendon localize and remove intra-tendinous calcification. Resecting more than 2/3 of the insertion is not advisable and if this much needs to be removed a tendon reconstruction should be considered.
¨ Achilles tendon reconstruction with the Flexor Hallucis Longus tendon
· Through a midline longitudinal incision the Achilles tendon is exposed and all degenerative tendon is excised.
· There are two possible techniques of reconstruction.
· Technique #1 – through a drill hole. This technique involves harvesting the FHL tendon in the arch area, passing it through a drill hole in the undisturbed posterior superior calcaneous, suturing it back to itself with a non-absorbable suture and then suture the stump to the remaining Achilles to the FHL construct. The difficult part of this procedure is mobilizing the FHL tendon and retracting it up to the posterior ankle due to the numerous adhesion to the FDL at and proximal to the knot of Henry.
· Technique #2 – fixation with suture anchor or interference screw. This technique involves finding the PHL tendon at the back of the ankle, maximally plantar flexing the hallux and ankle and then dividing the tendon as far distal as possible at the back of the ankle. The anastomosis to the FDL at the knot of Henry allow maintenance of FHL function without a distal repair. The posterior superior portion of the tuberosity can be excised and either a suture anchor or interference screw in the posterior superior calcaneous is used to hold the tendon graft.
· The remaining (normal) Achilles is sutured to the FHL construct.
· Post-op the repair is protected in a cast for six weeks then a walking boot that can be removed for gentle ROM exercises. Protected weight bearing is wise for at least 12 weeks in total.
¨ Repair of a ruptured Achilles tendon
· Two techniques are employed – open and percutaneous. Although not widely performed the percutaneous method is used by some authors to reduce the rate of wound related complications, which is high in this area, and to avoid interference with the blood supply to the injured tendon. The following discussion addresses the open technique, which is in more wide usage.
· Although a midline incision is probably fine I have used an incision that starts proximally just medial to the midline and extends to the lateral border of the tendon distally.
· The tendon in a mid-substance tear usually consists of two mop ends of tendon fibers.
· The ankle is plantar flexed and the ends apposed. Using a Kessler technique a strong non-absorbable suture is used to appose the tendon ends. With a slowly absorbing suture the tendon fibers are gathered and consolidated with a Krakow locking suture technique.
· Post-op the patient is casted for two weeks then placed in a device that allows partial weight bearing with the foot in an equinus position and very limited motion for an additional 4 weeks. At 6 weeks progressive ROM and resistive exercises are started but the repair is protected in a boot when ambulatory for the subsequent 4 weeks.
¨ Peroneal tendon debridement
· Incision and approach depends on the zone of involvement. In zone A follow the course of the tendons. In zone B I like to keep my incision below the sural nerve, carry the exposure to bone, then follow the lateral calcaneal wall up to the peroneal tubercle where the retinaculum can be divided to decompress and expose the tendons. If there is an abnormality of the grooves around the tubercle that are cause tendon fraying for example, the bony protuberances or ridges can be removed at this stage.
· If there are abnormalities they can be managed at this point. A common finding is a longitudinal split in the tendon with some associated tendon degeneration. If this is the case the degenerative tissue can be removed and the tendon repaired first internally then on the surface with a small caliber running absorbable suture.
¨ Peroneal tendon stabilization
· Incision is place just behind the posterior margin of the distal fibula.
· With subluxating tendons the retinaculum is lax, redundant and mobile over the distal fibula. Gasp it with a forceps and pull it anteriorly. Incise the retinaculum vertically in a line about 4 to 5 mms anterior to the posterior margin of the fibula.
· Retract the tendons posteriorly and deepen the fibular groove with a large oval burr. Make sure the distal edge of the groove is contoured and smooth. If tendon debridement is needed it can be carries out at this stage.
· Make six small drill holes vertically from the lateral fibular cortex into the groove and roughen the fibular cortex anterior to these drill holes.
· Starting at the level of the bottom drill hole pull the anterior piece of retinaculum posteriorly and pass a nonabsorbable suture through the retinaculum, through the drill hole, through the posterior piece of retinaculum (while it is being pulled anteriorly), out the adjacent drill hole and then through the anterior piece of retinaculum. Tag the suture and place two more sutures identically using remaining drill holes. When all sutures are placed tie them down.
· Post-op care consist of a cast for two weeks followed by a walking boot that is removed multiple times daily to put the ankle through an unloaded range of motion. Weight bearing in the boot is unrestricted. Strengthening with resistance is resumed at 6 weeks taking it a little is on resisted eversion at first.
¨ Resolution of symptoms in any patient with tendinopathy with non-operative management, once significant tendinosis has occurred, is a very gradual process and rapid return to activity or sudden discontinuation of mechanically protective devices often leads to a recurrence of symptoms.
¨ The indication for surgery in patients with intact but degenerative tendons is pain that has not resolved with a long course of mechanically protective management.
¨ Full recovery from debridement and reconstructive surgery often takes up to a year – let patients know this up front!
¨ If anatomical factors have predisposed the patient to the development of the problem (e.g. hindfoot varus > peroneal tendinosis, hindfoot valgus > tibialis posterior tendinosis) surgical correction should include procedures that correct malalignment. (See pes cavus and pes planus sections)
¨ More common etiologies of pes planus include
· Hypermobility syndrome
· Adult acquired flatfoot due to attenuation or rupture of the tibialis posterior tendon
· Congenital conditions – e.g. 1. residual forefoot varus from clubfoot causing a compensatory hindfoot valgus, 2. tarsal coalition, particularly talocalcaneal coalition, 3. congenital vertical talus.
· Tightness or contracture of the gastroc-soleus
¨ Pathophysiology and pathoanatomy of progressive pes planus
· In the flat foot the normal lateral translation and external rotation of the talus on the calcaneous, which usually locks the transverse tarsal joint in stance phase as the opposite limb swings through, does not occur in pes planus.
· As a result, instead of becoming a rigid lever arm at heel off that effectively transmits the force of the gastroc soleus contraction, the foot remains a flexible adaptive structure.
· Eventually following the path of least resistance the foot begins to break at the transverse tarsal joint (talonavicular-calcaneocuboid) level and dorsiflexion occurring at this level reduces the need for ankle dorsiflexion.
· With the gastroc soleus gets even tighter and pulls the already maligned calcaneous into further valgus making the situation at the transverse tarsal joint even worse.
· A the same time the navicular become progressively more laterally and dorsally located on the talar head with the resultant development of forefoot abductus and painful plantar and medial prominence of the talar head.
· Finally the calcaneous is so laterally translated that it lies under and begins to articulate with the distal fibula. This increases load on the fibula and fibular stress fractures may ensue.
¨ Clinical presentation depends largely on the etiology of the deformity.
· Patients with hypermobility syndrome will have had flat feet since early childhood and most have accommodated to their deformity. As adolescents they may experience medial ankle pain with sports due to overload of the tibialis posterior and in adult life the progressive deformity outlined above may result is symptoms from lateral impingement. The deformity in these patients is usually bilateral and relatively symmetric.
· The patients that seem most symptomatic from flatfoot are those with what is termed “adult acquired” flat foot deformity. These patients will have a history of medial ankle pain, due to tendinosis of the tibialis posterior that will be followed by progressive loss of the longitudinal arch as the tendon elongates with attrition. It is possible that painful inhibition alone will lead to the loss of arch height but it is more likely that unilateral arch collapse is indicative of permanent tendon damage from degeneration.
· In patients with tarsal coalition as the cause of the pes planus deformity, pain often onsets in adolescence as the flexible fibrocartilagenous coalitions become more rigid with ossification.
¨ Standing inspection of the feet and observation of gait are critical in the evaluation of pes planus. Status of the arch height, position of the hindfoot and the degree of forefoot abductus should be assessed. Gait should be observed closely for evidence of a midfoot break at heel off which would be indicative of accentuated mobility at the transverse tarsal joint and a tight gastro soleus.
¨ Single and double heel raise tests should be performed as outline under the Tendinopathy section.
· Inability to single heel rise and reduced heel inversion on double heel are indicative of possible compromise of the tibialis posterior although other problems may affect the patients ability to perform the test, especially with the single heel rise test.
¨ Flexibility of the deformity is important to evaluate, as this is a critical factor in surgical decision-making. Passive hindfoot motion is the best way to delineate this.
¨ Identifying contracture of the gastrocsoleus-Achilles complex is important in treatment planning as well. As outlined above dorsiflexion at the transverse tarsal joint may replace ankle dorsiflexion in patient with advance pes planus.
· To appreciate this the transverse tarsal joint is locked by bring the heel to the neutral position and inverting the forefoot, which locks the transverse tarsal joint prevent dorsiflexion at this level.
· If a gastrocsoleus contracture exists ankle dorsiflexion will be significantly reduced with the hindfoot held in neutral and rarely will the foot dorsiflex as far as the neutral position.
¨ Performing a mechanical assessment in helpful in distinguishing the location of the deformity and planning intervention. This performed with the patient prone and the foot in talonavicular neutral.
· The prime objective is to separate the hindfoot and forefoot components of the deformity. The calcaneal position is measured relative to the tibial (central calf) axis and the forefoot is measured relative to the vertical center line of the calcaneous.
· In pes planus the most common finding is that with the foot in talonavicular neutral the hindfoot is neutral or in slight valgus and the forefoot is in varus. The more long standing (and rigid) the deformity the more pronounced the deformity will be. Failing to appreciate this and correct this forefoot deformity is the greatest single error in the operative management of pes planus with triple arthrodesis.
¨ Standing radiographs of the feet and ankles are advisable. Routinely include AP standing of the feet and ankles and lateral standing of the each foot. Oblique films are helpful in identifying a calcaneonavicular coalition. Relevant angles include the talonavicular angle on the AP view, the talar-first metatarsal angle on the lateral and the angle of inclination of the first metatarsal.
¨ In adult acquired flatfoot deformity with unilateral involvement side-to-side comparison is most helpful in assessing the amount of deformation that has occurred with tibialis posterior dysfunction.
¨ The AP standing ankle is helpful in ruling out the possibility that collapse has not occurred at the ankle joint level as it might in the case of a ball and socket ankle or distal valgus deformity, but more important in advance cases being considered for a triple arthrodesis it will help identify medial (deltoid) ligament laxity which can be problematic in assessing mechanical position of the foot intra-operatively if the surgeon is not aware of the laxity pre-operatively. The surgeon may think that foot is appropriately aligned but not be aware that the talus is tilted in the mortis during this assessment.
¨ If coalition is suspected the oblique films will demonstrate a calcaneonavicular coalition but Harris-Beath axial calcaneal views will be needed to demonstrate a talocalcaneal coalition. To determine the extent of a talocalcaneal coalition coronal CT is most helpful.
¨ Non-operative management depends on the origin of the patient’s pain and the stage of the disease process.
¨ Hypermobility syndrome - For patients with long standing hypermobile flatfoot that develop pain from an irritated tibialis posterior or lateral impingement a custom longitudinal arch support may suffice to alleviate symptoms.
¨ Adult acquired flatfoot patients are generally not helped by a foot orthosis alone.
· If pain along the course of the tibialis posterior is exquisite and swelling severe a period of complete rest in a cast is appropriate to settle the pain while the a custom AFO is being fabricated. Cast immobilization is not discontinued and conversion to the brace is not initiated until the patient’s acute symptoms have resolved.
· My preference for a brace in these patients is a short articulated AFO which incorporates a UCBO type foot plate, an Oklahoma ankle hinge and a low profile anterior shell that grasps the lower tibia. The brace is rear entry with a posterior calf strap and must be used in a shoe.
¨ Tarsal coalition patient are helped considerably by the short articulated AFO which by effectively controlling hindfoot motion reduces stress on the coalition and relieves pain.
¨ Adult acquired flat foot deformity are separable into two groups; 1. those with a flexible deformity (Stage II posterior tibial tendon dysfunction) and 2. those with a rigid or fixed deformity (Stage III posterior tibial tendon dysfunction)
¨ Stage II are those with attenuation and elongation of the tibialis posterior tendon but at least to some degree a passively correctable deformity – the problem is this group still represents a fairly wide spectrum of deformity. If the patient’s hindfoot is arthrosis free the following represent a sequential thinking process in approaching these patients.
· FDL Transfer - The basic component of the reconstruction of the flexible flat foot due to tibialis posterior tendon dysfunction is replacement of the tendon with a transfer of the FDL (flexor digitorum longus) tendon.
· Hindfoot Osteotomy - For many years the FDL transfer was performed as an isolated procedure but this often failed to correct the deformity in many cases this led to persistent symptoms. To correct alignment but maintain motion two approaches were found to be successful in augmenting the FDL transfer; 1. medial displacement calcaneal osteotomy (MDCO) and 2. lateral column lengthening by adding an interposition graft to either an osteotomy of the anterior calcaneous or an arthrodesis of the calcaneocuboid joint. I cases with severe pre-op valgus even greater correction can be achieved with the additional resection of a medially based wedge from the osteotomy prior to fixation.
· Medial Displacement Calcaneal Osteotomy - My current approach is to perform the MDCO undergoing a reconstruction of a flexible pes planus as all by definition have hindfoot valgus an the MDCO is the best way, without a doubt, to move the tibial > calcaneal weight bearing line medially reducing the stress post op on the FDL transfer and improving foot appearance.
· Lateral Column Lengthening - There is however a group of patients with significant associated forefoot abductus, due to lateral subluxation of the navicular on the talus, that MDCO will fail to correct completely. It is these patients that a lateral column lengthening will help significantly. The issue is whether this should be performed instead of the MDCO or to augment it. Although many of us have been a long time in coming to this conclusion it is probably best to combine the procedures in the patients with a planovalgus foot with significant forefoot abductus.
· Medial Cuneiform Osteotomy - Patients with associated forefoot varus on mechanical evaluation (with the foot in talonavicular neutral, relative to the center line of the heel the plantar forefoot faces medially in the coronal plane) opening wedge osteotomy of the medial cuneiform to plantar flex the first ray should be considered to bring the forefoot to neutral alignment with the heel. This will not only improve foot mechanics but also appearance by enhancing the longitudinal arch.
· Achilles Tendon Lengthening – Finally if pre-operative evaluation showed significant limitation of ankle with the foot held in the talonavicular neutral position, lengthening of the Achilles tendon should be considered to prevent a tight gastroc soleus from having a deleterious effect on the reconstruction. This is best accomplished with a fractional lengthening performed at the musculotendinous junction.
¨ Stage III tibialis posterior tendon dysfunction (rigid acquired flat foot) or pes planovalgus with associated arthrosis are best managed with a triple arthrodesis that corrects alignment while simultaneously stabilizing the foot and eliminating arthrosis. Don’t take this procedure lightly – it is easy to do more damage than good. See the discussion of surgical technique. Triple arthrodesis is also the procedure of choice to relieve lateral ankle pain in hypermobility syndrome patients with such severe pes planus that they have calcaneal-fibular abutment.
· To achieved the desired correction of foot alignment it is often necessary to modify or augment the triple arthrodesis. Most common modifications include; 1. the addition of an interposition bone graft to distracted the arthrodesis of the calcaneocuboid joint to correct forefoot abductus and 2. opening wedge osteotomy of the first metatarsal to plantar flex the first ray and correct forefoot varus.
¨ FDL transfer for chronic tibialis posterior tendinosis
· Incision / exposure – the incision begins about 3 cm above the malleolus and follows the course of the tendon around the medial malleolus to the medial prominence of the navicular then heads gradually plantar to follow the plantar edge of the first metatarsal base
· Tibialis posterior tendon management – The tendon is inspected. Almost invariably there is extensive degeneration with segmental thickening due to scarring, longitudinal splits, partial transverse ruptures and even intrinsic cysts. The tendon is resected to a point proximal to the malleolus and traction is applied to the proximal stump to assess the status of the tibialis posterior muscle belly. If the stump cannot be pulled distally and demonstrates no pliability one should assume that the muscle is fibrotic and non-contractile and suturing it to the FDL after the transfer is complete is not advisable.
· Synovectomy – If there is marked inflammation of the tibialis posterior sheath the inflamed synovium should be debrided.
· FDL preparation – Dissection is carried under the medial cuneiform and the FDL and FHL tendons are identified distal to the Knot of Henry when the tendons cross. By putting traction on the tendons and observing toe flexion, the two tendons are differentiated. Distal to the Knot of Henry the FDL is transected, the tendon ends tagged and the proximal tendon is mobilized. The extensive adhesion between the two tendons at and proximal to the Knot can make separating the tendons and pulling the FDL proximal to allow it to be relocated can be very difficult.
· The distal FDL tendon – The distal stump of the FDL is sutured to the FHL side to side. Be careful not to put tension on the FDL while suturing the two together as this will result in clawing of lesser toes in ankle dorsiflexion (like after a deep calf compartment syndrome) and reduced flexing power of the hallux.
· FDL transfer – Once the FDL is pulled out proximal to the medial malleolus it is relocated into the vacated sheath of the tibialis posterior. A drill hole is made dorsal to plantar in the navicular tuberosity. Make sure on pre-op films that there is not an accessory navicular. If there is it must be resected prior to making the drill hole. The tendon is then passed from plantar to dorsal and suture back to itself and to soft tissue on the navicular with a few non-absorbable sutures. The tendon should be sutured in place under tension with the foot in slight plantar flexion and talonavicular neutral. It is possible to suture the tendon in too tight. Other possible techniques of tendon fixation include the use of suture anchors or an interference screw in the drill hole with the tendon. There really isn’t need for the added expense of these unless there is inadequate tendon length to either pass it through a drill hole (then use the anchor) or once in the drill hole bring it back to suture to itself (use the interference screw).
¨ Medial Displacement Calcaneal Osteotomy
· Incision – The skin incision follows exactly the line of the calcaneal osteotomy to be performed. The incision extends from the top of the calcaneous mid way between the Achilles tendon and the posterior facet to a point on the inferior calcaneous just distal to the plantar tubercles. This will keep the incision just below and behind the sural nerve, the structure most at risk in inadvertent injury.
· Osteotomy – The osteotomy in made with a microsagittal saw exactly in the line described for the incision above. Once complete it is gradually distracted with a lamina spreader with very wide blades to prevent the spreader from sinking into the cancellous bone of the calcaneous. Distraction should be continued until there is about 1 cm separation.
· Medial based wedge resection – If hindfoot valgus is severe pre-operatively a medial based wedge can be resected from the apical portion of the tuberosity. Place the microsagittal saw at the cut edge of the apical side of the osteotomy and moving the saw continuously back and forth remove a thin medially based wedge (about 3 mm at the base) of cancellous bone. If possible try to leave the medial cortex intact (this can be a little difficult) to hook around the medial side after displacement.
· Displacement / Fixation – Translate the tuberosity medially to gain approximately 1 cm of total displacement. Pass the guide wire for a 6.5 or 7.0 mm canullated screw from the apex of the calcaneous across the osteotomy in a perpendicular line to a point just below the posterior facet. Check pin placement and to ensure that the tuberosity has not migrated dorsally with displacement, with the mini c-arm. Prior to drilling the hole place a second k-wire above or below and parallel to the first to prevent displacement with drilling. After drilling, under fluoroscopic control, up close to subchondral bone a partially threaded screw with a 16 mm thread is placed. One screw seems to be sufficient in good quality bone. Make sure the screw head is not protuberant.
¨ Lateral column lengthening
· Lengthening through the calcaneous vs. the calcaneocuboid joint – With bench research based evidence that lateral column lengthening through the anterior calcaneous increases compression in the calcaneocuboid joint, possibly predisposing it to osteoarthrosis, I have performed my lateral column lengthenings through the calcaneal cuboid joint as loss of motion at this joint has fairly minimal impact on total hindfoot motion.
· Calcaneocuboid preparation – The articular surfaces of the calcaneal cuboid joints are resected with parallel cuts with a microsagittal saw.
· Interposition graft – My preference has been to use a tricortical wedge of autogenous iliac crest but others have opted to various types of allograft. Whatever is used the objective is to correct forefoot abduction (and talonavicular subluxation) with a wedge shaped block of bone. The shape of the interposition graft depends on the dimensions of the defect with a lamina spreader in the defect distracting joint or osteotomy.
· Fixation – With the graft impacted in place fixation is best achieved with a plate or large staple. I have had troubles achieving stable fixation with screws due to the obliquity with which they need to be placed.
¨ Triple arthrodesis
· Two incisions: (a) Lateral incision extending from the tip of the fibula to the anterior process of the calcaneous and then distal and plantar over the cuboid towards the lateral aspect of the base of the 4th metatarsal. (b) Dorsal medial incision placed directly over the tibialis anterior at the ankle level and lateral to the tendon distally over the navicular as the tendon heads medial to its insertion on the first metatarsal base.
· Alignment correction - Below the individual components of a triple arthrodesis are split up and describes as separate procedures but in performing a triple all joint surfaces are first resected, and in sequence each joint grafted, realigned and fixed. The usual sequence of alignment correction and fixation is a follows: (a) Cancellous bone graft is placed into the subtalar joint then the calcaneous is translated medially and internally rotated then fixed provisionally with a wire from the canullated screw set. (b) Bone graft is placed into the talonavicular joint, the navicular is translated medially to centralized it on the talar head and the forefoot is “pronated” in an attempt to correct forefoot varus, an the talonavicular joint is fixed provisionally with a wire from the navicular tuberosity into the talar head. (c) Finally the calcaneal cuboid joint can be provisionally fixed with a k-wire. (d) Alignment is now checked. The calcaneous should now be centralized under the tibial axis and valgus deviation corrected. With the two thumb test, evenly loading the plantar aspect of the first and fifth metatarsal heads, the plane of the thumbs should be perpendicular to the long axis of the tibia and the now restored vertical axis of the calcaneous. If the forefoot is in varus you can try to correct this by adjusting transverse tarsal joint position but this is often difficult. It is usually easier to correct forefoot varus with a plantar flexion osteotomy of the medial cuneiform or first metatarsal base. (e) The position of pins across the subtalar and talonavicular joints is checked with the mini c-arm before screws are placed.
· Subtalar arthrodesis – Through the lateral incision the sinus tarsi is is exposed and enough of the sinus contents are removed to see the anterior (talar) edge of the posterior facet. > An osteotome is passed up into the joint to gage its orientation and curvature. > A lamina spreader is place into the sinus to open the posterior facet and the articular cartilage and subchondral bone (down to cancellous bone) is carefully remove with the osteotome. Care must be taken in removing the articular surface of the posterior and medial talus as this portion of the talus curves abruptly downwards and failure to closely follow the curvature (going straight through with the osteotome) will result in disassociation of the posterior 1/3 from the remainder of the talar body. > Once the joint is prepared it is packed with graft and fixed with a 6.5 or 7.0 canullated screw. If only the subtalar joint was being fused the screws are placed from the apex of the calcaneous across the joint and into the talus with position being check with the mini c-arm. With a triple arthrodesis a single screw can easily be placed from the talar neck across the subtalar joint and with the additional fixation of the transverse tarsal joint that lend additional stability a second screw is not needed.
· Talonavicular arthrodesis – The talonavicular joint is exposed through an incision over the tibialis anterior tendon. > Articular surfaces are removed with an osteotome using a spreader to allow visualization of the joint. Removing the articular surface from the talar head is pretty straight forward but the curvature and thickness of the proximal articular surface can make its removal to a uniform cancellous surface somewhat difficult. > With cancellous bone exposed a small amount of the cancellous bone can be added to fill any gaps in apposition. > The talonavicular fusion is fixed with a screw place from the medial aspect of the uncovered navicular tuberosity into the talar head. The position of this fixation combine with the laterally place fixation of the calcaneocuboid joint makes for a stable construct at the transverse tarsal level.
· Calcaneocuboid arthrodesis - Through the distal portion of the lateral incision the calcaneocuboid joint is visualized. > If lengthening of the lateral column is planned as part of the triple arthrodesis the articular surfaces are resected with a microsagittal saw to create planar surfaces for the acceptance of an distraction interposition tricortical graft. If distraction graft is not planned the surfaces can be removed with an osteotome following joint contours to minimize shortening. > Graft is inserted in to the joint and the fusion fixed with a dorsolateral staple or a spanning plate.
¨ Medial cuneiform plantar flexion osteotomy
· Incision / exposure – A longitudinal incision is placed over the dorsal aspect of the medial cuneiform. If a talonavicular arthrodesis has been performed this incision will be a distal extension of the incision for this more proximal fusion.
· Opening wedge osteotomy – Starting in the middle of the medial cuneiform a transverse osteotomy is made with a sagittal saw from dorsal to plantar with slight inclination to towards alignment with the first tarsometatarsal (TMT) joint.
· Interposition graft – The osteotomy is wedged open (e.g. with a small lamina spreader) and using the two thumb test to the amount of correction necessary to eliminate forefoot varus is gauged. A wedge shaped graft of the necessary dimensions is inserted and forefoot position is rechecked with the two-thumb test.
· Fixation – The osteotomy is fixed with a screw from dorsal distal to plantar proximal that transfixes the graft.
¨ Improper procedure selection is a significant pitfall, particularly:
· Performing a tibialis posterior reconstruction for the adult acquired flatfoot without performing an associated bony procedure that will attempt to correct malalignment issues that will lead to persistent deformity and/or pain post-op.
· Performing tendon transfers or corrective osteotomies on a foot that either has arthritic hindfoot articulations or has fixed deformity (no motion in the hindfoot articulations) rather than a triple arthrodesis.
· Failing to recognize the presence of a tarsal coalition and failing to manage the coalition. Also if a calcaneal navicular coalition is diagnosed, failing to diagnose and treat a coexisting talocalcaneal coalition.
¨ The most common error in the surgical management of pes planus is the malpositioned triple arthrodesis where hindfoot correction leaves an uncompensated rigid forefoot varus, which if uncorrected, leads to over load of the lateral ankle and premature ankle arthrosis. Forefoot position should be checked intra-operatively and if varus is present it should be addressed at the time of the index surgery.
¨ With tarsal coalition attempting to resect talocalcaneal bar that has a significant component of articular involvement has a very high failure rate. Since even after a “successful” resection of an intra-articular talocalcaneal bar joint motion is so limited it is probably better to perform a subtalar arthrodesis, which gives more reliable pain relief, as a primary procedure. Resecting calcaneal navicular bars, which are extra-articular is ia different matter and has a much more predictable outcome.