The main problems encountered in the tarsal joints are arthritis and post-traumatic pain and instability.
The subtalar and talonavicular joints are frequently affected by rheumatoid arthritis, leading to a flatfoot deformity as the static restraints are overcome by the forces of gait (Keenan 1990). Lesser tarsal joints may also be affected by RA and this may contribute to flatfoot in some patients.
Post-traumatic OA may affect any of the tarsal joints:
- Subtalar OA mainly after calcaneal fractures, but also ankle/subtalar ligament injuries and peritalar dislocations
- Talonavicular and calcaneocuboid OA mainly after midtarsal subluxations, some of which are quite subtle
- Tarsometatarsal OA mainly after Lisfranc and “subtle Lisfranc” injuries
Primary OA, often as part of generalised OA, is rarely commented on in textbooks, but is seen reasonably frequently in practice, especially in the TMT joints. Osteoarthritis may also occur in association with tarsal coalitions.
Subtalar joint pain is felt mainly in the lateral hindfoot on activity. If there is a valgus hindfoot or synovitis, there may be impingement pain felt mainly on lateral hindfoot deviation. Some patients complain of instability or locking, which may be described as being in the ankle.
Talonavicular pain is felt on the medial, dorsal or occasionally lateral midfoot. Patients often describe it as being in the ankle, and it is important to clarify exactly where “ankle” symptoms are felt. Dorsal osteophytes may present as painful lumps or be misinterpreted as ganglia.
Calcaneocuboid pain is felt on the lateral side of the hindfoot. It may be difficult to distinguish from peroneal tendon pain. Some patients complain of clicking or instability.
Tarsometatarsal pain is usually felt on the dorsum or (1 st TMT joint) medial aspect of the midfoot. Sometimes pain is referred into the forefoot and may even present as apparent metatarsalgia. Large osteophytes causing pressure on the shoes, either dorsally or on the plantar aspect of the 1 st TMT joint may be the main complaint.
All patients should be asked about:
- inflammatory arthropathy
- neurological disease
Examination may show features of a generalised arthropathy, or, less commonly, neurological disease. There may be a generalised deformity of the foot, most commonly flatfoot, in which case the Achilles tendon may be tight and ankle dorsiflexion limited. The function of the long tendons, particularly the tibialis posterior, should be assessed by standard tests.
Examination of individual tarsal joints will generally show reduced movement in the presence of arthritis. Reproduction of symptoms by manipulation of the joints helps to localise the source of pain. Pressure areas related to osteophytes should be noted. Any forefoot abnormalities should also be noted.
An apparent underlying inflammatory arthropathy or neurological disorder should be investigated by standard means.
The tarsal joints should be imaged by standing AP, lateral and oblique radiographs. In the presence of hindfoot malalignment a standing hindfoot alignment radiograph will help tell whether the deformity is at the ankle or subtalar level, or both. Talocalcaneal coalitions are often apparent on a lateral view, but an axial calcaneal view or CT will give additional information. Calcaneonavicular coalitions are usually apparent on an oblique view of the midfoot.
CT can help assess complex deformities. Either CT or MR can be used to evaluate coalitions.
Arthritic pain can usually be controlled with analgesics and/or NSAIDs; there is little evidence that NSAIDs have additional efficacy. Shoes should be chosen with support and accommodation in mind. Mobile deformities may have less pressure problems with corrective orthoses, while stiff deformities may be more comfortable with off-the-shelf or moulded supportive orthoses. Physiotherapy is often useful to optimise range of motion, muscle strength and proprioception, especially in the presence of complaints of instability.
Steroid injections into the tarsal joints can, anecdotally, be useful to control symptoms, although there are no published results.
There are no formal studies of the effectiveness of non-surgical treatment of hindfoot arthritis.
The subtalar, talonavicular or calcaneocuboid joints may be fused either singly or in a variety of combinations. Fusion may be done for:
- Painful arthritis affecting all three joints
- Hind/midfoot deformity
- Hind/midfoot instability, especially in association with paralysis
or a combination of these. Single joint fusions are more likely to be for isolated pathology such as arthritis while deformity correction ± stabilisation more often requires multiple fusions, but this is not absolute. For instance, isolated fusion of the subtalar, talonavicular or calcaneocuboid joints (in the latter case with intercalcated bone graft for lateral column lengthening) has been used as part of a flatfoot reconstruction.
“Double fusion” has been used in two distinct ways:
- Fusion of the talonavicular and calcaneocuboid joints (ie the Chopart joint), usually as part of a flatfoot reconstruction (Mann 1999, Thelen 2009). This was aimed at gaining increased stability especially in obese patients.
- Fusion of the subtalar and talonavicular joints (Sammarco 2006, Jackson 2007, Knupp 2009, Brilhault 2009, Phillipot 2010). This aims to achieve the correction and stability of a triple fusion without involving the calcaneocuboid joint. All but Sammarco’s series were done through a single medial incision as described by Jeng (2005) in patients with severe valgus deformity and poor lateral skin.
“Triple fusion” refers to fusion of all three hindfoot joints. This was the workhorse of hindfoot correction and stabilisation for many years, especially in polio. As pathology has changed more selective fusions have become commoner, but the triple fusion is an important part of the repertoire fo the foot and ankle surgeon.
Traditionally, exposure to all three joints was gained through a single curved incision over the dorsolateral aspect of the hindfoot. More commonly separate incisions are now used, one running from the tip of the fibula to a couple of centimetres distal to the calcaneocuboid joint, the other from the medial malleolus to the naviculocuneiform joint, midway between tibailis posterior and anterior. Both incisions are deepened carefully with blunt dissection to control many veins on the medial side and to avoid the branches of the saphenous nerve medially and the sural and superficial peroneal nerves and the common communicating branch laterally. The extensor digitorum brevis and the root of the inferior extensor retinaculum are elevated in the lateral incision and the joint capsules opened. Access to the lateral part of the talonavicular joint may be easiest through the lateral approach, especially in pes cavus. In some deformed or arthritic feet, the region where the talus, calcaneus, navicular and cuboid come together may be very stiff and need to be formally released. Retraction needs to be careful to avoid damage to nearby tendons and neurovascular bundles. Laminar spreaders are useful to achieve adequate visualisation.
In patients with severe hindfoot valgus and poor skin, the lateral incision can be difficult to close after deformity correction. Myerson and Jeng (2006) described a single medial approach in such patients through which all three joints can be accessed, although Jackson (2007), Brilhault (2009), Knupp (2009) and Phillipot (2010) omitted the calcaneocuboid fusion without ill effects (and Jackson also accessed the ankle).
Arthroscopic subtalar fusion has been described in several series although it has not yet replaced open fusion. An arthroscopic method has been described for triple fusion (Liu 2007) though this has not been reported beyond the originator.
The joint surfaces are removed with a combination of curette, burr, gouge and osteotome. The technique is essentially the same for arthroscopic fusion. Care should be taken not to over-resect bone or to create divots, especially in the concave surfaces. In the subtalar joint it is important to adequately debride the middle and anterior facets. Although most deformity can be corrected by rotating or translating the joint surfaces, occasionally it is necessary to remove bone wedges to correct severe deformity. The Lambrinudi technique excises part of the talar head to allow navicular elevation to correct severe cavus deformity.
Most deformities are best corrected at the talonavicular joint first; the subtalar joint will the usually follow although some additional correction may be required. Child (2009) found that sagittal plane deformity was mainly corrected at the talonavicular joint and coronal deformity at the subtalar joint. Normally a position of 5degrees valgus and collinear talus and first metatarsal is ideal, although some compromise may be necessary depending on the initial deformity, bone stock and soft tissue condition. Bony defects can be grafted with cancellous bone which can often be obtained locally or from the tibia; Rosenfeld (2005) found no difference in union rate or time to union in a series of triple fusions using only local graft. However, iliac crest or allograft bone may be preferred for revision surgery or for structural graft. In particular, correction of a severe flatfoot deformity may lengthen the lateral column and leave a significant gap in the calcaneocuboid joint for which a tricortical graft may be needed (Henderson 2008).
Fixation may be with screws, staples or plates; most authors prefer compression screw fixation where possible. Double screw fixation has been shown to be more stable than single screws in both subtalar and talonavicular joints in cadavers (Chuckpaiwong 2009, Rosenfeld 2005). Gosch (2006) demonstrated that subtalar screws placed vertically through the calcaneum were as stable as those placed from posteriorly, offering an alternative in case of bone or soft tissue problems. McGlamry found the pull-out strength of screws placed from posteroinferior to be superior to those placed through the talar neck from anterosuperior, although both were adequately stable. In the talonavucular joint , Jarrell (2009) found that three screws were as stable as a reconstruction plate with or without screw. All of these were cadaver studies. DeCarbo (2010) reviewed 113 open subtalar fusions, 89 of which had singles screw fixation and 24 double screws. There were no differences in non-union, revision or hardware removal. Allocation to treatment was by surgeon preference and the overall non-union rate (16.8%) was unusually high.
Direct observation and intra-opeartive fluoroscopy are normally used to assess and guide screw placement. Easley (2008) used computed-guided screw placement in cadavers. The number of attempts required to position guidewires and the fluoroscopy time was reduced for both experienced and inexperienced surgeons, and the accuracy of screw placements was increased for both groups. However, operative time was doubled for experienced surgeons, though it was unchanged for inexperienced surgeons. Richter (2008) demonstrated a high degree of accuracy in 100 computer-guided ankle and hindfoot fusions. Setup took an average of 6 minutes and there were three computer failures.
The wounds are closed according to preference and a plaster splint is usually applied to prevent equinus.
Most surgeons restrict weightbearing and use cast immobilisation for at least the first 4-6 weeks. There are no series comparing more or less restrictive methods of post-operative care. Patients may be allowed weightbearing in a walker boot after 4-6 weeks, or remain in cast until united.
Assessment of union has traditionally been by plain radiography. However, Coughlin (2006) showed that CT and radiography differed substantially and recommended that CT be adopted as the standard of assessment. Dorsey (2009) found that 33% complete fusion on CT provided an accurate cut-off between clinically and surgically united and non-united ankle and subtalar fusions.
Triple fusion was the traditional method of correcting and stabilising the hindfoot. Indeed, the author was taught that if one hindfoot joint was to be fused the others would become arthritic because of the increased stresses and need fused in the future, so a triple fusion should be done at the outset. The literature on isolated fusion does not support this. Approximately 400 isolated open subtalar fusions have been reported, with 37 non-unions (11%). 30 of these non-unions were in one series where smaoking, revision surgery and avascular necrosis predicted non-union; in the remaining series the rate was 3%. In addition, 58 arthroscopic fusions with one non-union (2%) have been reported. Where adjacent joint arthritic progression was reported, 5/147 found progression in one adjacent joint each, only one of which was symptomatic. In isolated talonavicular fusion, there were 2 non-unions in 55 patients (4%) and adjacent joints had progressed in 7 patients. None of these series reported subsequent extension of the fusion in any patient. In 840 reported triple fusions there were 19 non-unions(2%), mostly in the subtalar or talonavicular joints. These series had short or intermediate follow-up and not all reported adjacent joint progression; where this data was available the rate of OA in adjacent joints at follow-up was 48%, mostly in the ankle. Saltzman, however, reported much longer follow-up and found that at 25 years 69%, and at 44years 100%, had ankle OA, with similar results for the naviculocuneiform joints; however, most patients were still satisfied with the clinical results despite significant pain in 65%. Only two ankle fusions were reported as extensions of fusion. Interestingly, deHeus (1997) found no difference in progression in adjacent joints between feet that had undergone subtalar or triple fusion and the contralateral unoperated foot at 6-15y follow-up. Two basic science studies are interesting: Beaudouin (1991) found that isolated subtalar fusion significantly altered contact characteristics of both ankle and subtalar joints, while Suckel (2007) found pressure changes in both ankle and naviculocuneiform joints after talonavicular and triple fusions, but these were less after talonavicular fusion. Therefore, it seems appropriate to select the extent of fusion based on clinical and imaging assessment of the source of symptoms. While other joints may become arthritic in the future it is unlikely that extension of the fusion will be required.
It is difficult to compare clinical results in different series, due to the differences in underlying pathology and operative techniques. Overall, subtalar fusion is most likely to give good clinical results with the lowest non-union rate. The rate of adjacent foot pain and non-union may be a little higher with talonavicular fusion, although the difference is not large, and talonavicular fusion is more efficient at correcting hindfoot deformity. Patients tend to have more residual symptoms after triple fusion, although most still gain benefit from their operations. Interestingly, Daglar (2008) found the results to be better in non-neurogenic underlying diagnoses than in neurogenic. It seems likely that fusion of the calcaneocuboid joint can be omitted in many patients where the joint is not in itself symptomatic. The single medial approach is very useful in patients with severe valgus deformity and should certainly be in the foot and ankle surgeon’s repertoire.
Instability of the subtalar joint usually occurs in association with ankle ligament injuries. Some series of ankle instability report subtalar problems in 10% of cases, others rarely identify it. This may, to some extent, reflect how carefully the subtalar joint is evaluated.
Patients usually complain of giving way or pain “in the ankle”, occasionally of clicking or locking. Occasionally excess laxity of the subtalar joint can be detected clinically with a medial displacement or anteromedial stress test. There is often associated ankle instability or peroneal tendon problems.
Standard ankle anterior draw or talar tilt stress radiographs may demonstrate abnormal movement at the subtalar joint. Oblique stress radiographs may also be useful. MR can show subtalar ligament lesions and joint surface abnormalities.
As with ankle instability, most patients respond to a rehabilitation programme to improve muscle strength, flexibility and proprioception. Persistent symptoms may be treated by stabilisation:
- Plication of the lateral talocalcaneal ligament and calcaneocuboid ligament
- Reconstruction with a tendon graft, using the Chrisman-Snook or anatomical reconstruction if there is additional ankle instability
Arthroscopic debridement of the subtalar joint can be useful for synovitis and joint surface injuries, and this may have a more significant role to play in the future.
If end-stage arthritis develops a fusion may be necessary
This is an uncommon post-traumatic problem which presents with lateral hindfoot pain and clicking. It may be difficulat to distinguish from peroneal tendonopathy. Manual stress testing or stress radiography may reproduce pain or show abnormal movement.
Local physiotherapy and a rehabilitation programme are usually helpful. Steroid injection into the joint can help pain.
Stabilisation techniques with tendon graft have been described, with fusion as a last resort.
Bossing, usually over the TMT or talonavicular joints, is quite common and usually presents as a swelling that rubs on the shoes. There may be an overlying adventitious bursa which can be confused with a ganglion. Some TMT bosses irritate the deep peroneal nerve. If no arthritic changes are shown by clinical or radiological assessment, these bosses are probably quite benign, although there are no outcome studies.
Many tarsal bosses show little on radiographs, implying that a good deal of the swelling is soft tissue.
Some patients need only reassurance or advice on choosing shoes with enough room to accommodate the boss. Surgical removal is usually successful, although some patients find the scar still rubs on their shoes. We have not had any new deep peroneal nerve lesions, and about 10% recurrence, usually within 2 years
Arthroeresis is the stabilisation of the subtalar joint by insertion of an implant that holds it in a corrected position. A variety of screw and peg devices have been described. Most modern implants can be inserted by a minimal incision technique.
Most series of arthroeresis have reported its use in children. Two series in adult patients have been reported.
Viladot (2003) reported 21 patients with AAFF Johnson stage 2 who underwent medial soft tissue surgery, correction of subtalar malalignment with a Kalix implant and Achilles lengthening where necessary (11 patients). The Kalix implant was inserted in the sinus tarsi using trial implants to assess size. Eight patients had a tenosynovectomy of tibialis posterior, one a plication, four a side-to-side suture to FDL and six an FHL transfer to the navicular. A BKW cast was worn for 6 weeks and an insole for 6-12 months. Patients were reviewed at 19-36 (mean 27) months. AOFAS score improved from median 47 (16-80) to median 81 (33-100). Moreau-Costa-Bartani angle improved 14deg and Kite angle 9deg. Two patients were dissatisfied because of pain. Two implants were removed because of pain, and four other patients had sinus tarsi pain post-op which “improved”. No other complications were reported.
Needleman (2006) reported 28 flexible flatfeet in 23 adult patients treated with subtalar arthroereisis with a Maxwell-Brancheau implant and a variety of other procedures. 14 feet in 13 were flexible (stage 2?) AAFF, 13 in 9 patients had congenital flexible flatfeet and one had a neurological deformity. All had gastrosoleus contractures and 14 forefoot varus. Implant inserted over a guide pin using sizers to reduce subtalar movement to 2 deg eversion. All had TA lengthening or gastrocnemius recession, 13 had FDL transfer to the navicular, 12 had dorsal open wedge osteotomy of the medial cuneiform and several forefoot procedures; there were no lateral column lengthenings. A BK cast was worn for 4-6 weeks with weightbearing at 2 weeks if no cuneiform osteotomy was performed. Review was clinical or by telephone at 7-76 (mean 44) months post-op, presumably by the author who was also the surgeon. Mean AOFAS score improved from 52 to 87. There were significant improvements in pain, ability to walk, activity level and footwear limitations. There were improvements in all radiographic measurements which were maintained at final follow-up. 13/28 feet (46%) had post-operative sinus tarsi pain and 11 had the implant removed 5-22 months after the index operation. Removal resulted in a small, non-significant loss of correction. Three feet had moderate-poor results after implant removal, but the scores in the others were similar to the rest of the population. “There were no other complications”.
In both these studies, the mean scores were similar to those for realignment calcaneal osteotomy or subtalar fusion. This procedure, however, has a predictable need for re-operation in a significant number of patients. Most patients had a number of the other procedures often used to correct adult flatfoot. It has been suggested that this is a simpler procedure than a calcaneal osteotomy with a simpler post-operative course and less morbidity, but it is not clear from these series that this is the case. Unless a RCT indicates otherwise, it seems difficult to justify this procedure rather than the more established calcaneal osteotomy. It also seems remarkable that 49 major hind/midfoot reconstructions could be performed on patients with a mean age of 55 without any complications.