DEFINITION

A calcaneal malunion refers to residual bony malalignment and associated clinical sequelae resulting from inadequate treatment of a displaced intra-articular calcaneal fracture.

 

 

ANATOMY

 

The calcaneus is an odd-shaped bone which supports full body weight and provides a lever arm through which the powerful gastrocsoleus complex assists with forward propulsion during gait (FIG 1).

 

The calcaneus also provides articulations for the subtalar and calcaneocuboid joints and thus is integral to function of the triple joint complex of the hindfoot for normal ambulation and accommodation to uneven ground (FIG 2).

 

The normal orientation of the calcaneus is reflected radiographically as calcaneal pitch, calcaneal height, and calcaneal length, which directly affect the three-dimensional alignment of the hindfoot and midfoot and indirectly affect ankle dorsiflexion (FIG 3).

 

PATHOGENESIS

 

In the event of a displaced intra-articular calcaneal fracture, there is typically not only intra-articular displacement of the posterior facet but also loss of calcaneal height, shortening and varus angulation of the calcaneal tuberosity, extension into the anterior process or calcaneocuboid joint, and expansion of the lateral calcaneal wall.

 

Nonoperative treatment, or inadequate operative treatment, of a displaced intra-articular calcaneal fracture results in a calcaneal malunion, which affects function of the ankle, subtalar, and calcaneocuboid joints, and leads to pain and disability.4,15,16 Associated sequelae include the following:

 

 

 

 

FIG 1 • The calcaneus serves as a lever arm for the powerful gastrocsoleus complex.

 

 

Posttraumatic subtalar and calcaneocuboid arthritis due to residual articular incongruity8,17

 

Lateral subfibular impingement from residual lateral wall expansion and heel widening3,10

 

Peroneal tendon stenosis, tenosynovitis, or subluxation/dislocation as a result of adjacent bony prominence2,5,13

 

 

Anterior ankle impingement and loss of ankle dorsiflexion due to loss of calcaneal height, resulting in relative dorsiflexion of talus3 Hindfoot malalignment (typically varus) affecting gait pattern and shoe wear and potentially producing a leg length discrepancy14

NATURAL HISTORY

 

Patients with displaced intra-articular calcaneal fractures that go on to malunion typically have a poor result, including pain with weight bearing, limitations in shoe wear, secondary gait alterations, and progressive posttraumatic subtalar arthritis.6,12

PATIENT HISTORY AND PHYSICAL FINDINGS

 

 

History of prior calcaneal fracture (displaced intra-articular fracture)—note prior method of treatment (operative or nonoperative) Pain with weight bearing (standing or walking, particularly on uneven terrain)

 

Thorough examination of the ankle and hindfoot should also include assessment of the following:

 

 

Skin and soft tissue envelope, including location of previous surgical incisions, overall mobility of lateral hindfoot skin, swelling, or any dystrophic changes where present

 

Neurovascular status (particularly the presence or absence of palpable pulses)

 

 

 

FIG 2 • Normal weight-bearing lateral radiograph demonstrating posterior and middle facets of subtalar joint (black arrows) and calcaneocuboid joint (white arrows).

 

 

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FIG 3 • Normal weight-bearing lateral radiograph. Note downward orientation of talus. (A) Calcaneal pitch angle. (B) Calcaneal height. (C) Talo-first metatarsal angle.

 

 

 

Hindfoot malalignment: Excessive hindfoot varus or valgus relative to uninvolved limb represents malalignment. Subtalar range of motion: Decreased subtalar range of motion may result from posttraumatic arthritis.

 

Subtalar arthritis: Tenderness to palpation suggests articular degeneration.

 

Subfibular impingement, bony prominence, and tenderness suggest peroneal stenosis or tenosynovitis from residual lateral wall expansion. Peroneal tendons may actually be subluxed or dislocated in severe cases.

 

Ankle range of motion: Decreased dorsiflexion compared to uninvolved limb may indicate anterior impingement from relative dorsiflexion of talus and loss of calcaneal height.

 

IMAGING AND OTHER DIAGNOSTIC STUDIES

 

Standard weight-bearing radiographs of the ankle and foot, in addition to a Harris axial view of the calcaneus, reveal the calcaneal malunion.

 

The lateral view of the hindfoot demonstrates loss of calcaneal height and relative dorsiflexion of the talus (FIG 4).

 

The mortise view of the ankle demonstrates residual lateral wall expansion and degenerative changes in the subtalar joint as well as a fracture-dislocation variant fragment where present (FIGS 5 and 6).

 

The axial view shows residual shortening of the calcaneus and any hindfoot malalignment were present (FIG 7).

 

Once the diagnosis is established, a computed tomography (CT) scan of the calcaneus, including axial, sagittal, and 30-degree semicoronal images, further delineates the extent of subtalar and calcaneocuboid arthritic change, hindfoot malalignment, lateral wall exostosis, subfibular impingement, as well as any associated talar or other ankle joint pathology (FIGS 8, 9 and 10).

 

 

 

 

FIG 4 • Weight-bearing lateral radiograph of calcaneal malunion. Note loss of calcaneal height (black arrows), producing relative dorsiflexion of talus and anterior impingement at ankle joint (white arrow).

 

 

 

FIG 5 • Weight-bearing mortise radiograph of calcaneal malunion. Note residual intra-articular step-off and associated degenerative changes (black arrows).

 

 

DIFFERENTIAL DIAGNOSIS

Posttraumatic subtalar arthritis (without malunion) Subtalar osteoarthritis

Calcaneal fracture nonunion

Lateral ankle instability or peroneal tendon pathology

 

 

NONOPERATIVE MANAGEMENT

 

Nonoperative treatment options are limited but consists primarily of supportive modalities to lessen inflammation and painful motion through the hindfoot.

 

A lace-up ankle brace, University of California at Berkeley Laboratory, ankle-foot orthosis, or Arizona-type brace may

 

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be beneficial in limiting painful subtalar motion and providing symptomatic relief. A prefabricated fracture boot may be used intermittently for episodes of arthritic flare-up.

 

 

 

FIG 6 • Weight-bearing mortise radiograph of calcaneal malunion from fracture-dislocation variant pattern. Note residually dislocated posterolateral fragment wedged within talofibular joint (black arrows) and subtle varus tilt within ankle mortise (white arrow), suggesting incompetence of lateral ligamentous complex.

 

 

 

FIG 7 • Axial radiograph of calcaneal malunion. Note marked residual shortening (black arrows) and varus angulation of calcaneal tuberosity (dashed lines).

 

 

 

Intermittent use of nonsteroidal anti-inflammatory medication can also be beneficial in disrupting the inflammatory cycle. Activity modification, such as limited standing and walking, particularly on uneven terrain, may also lessen symptoms.

SURGICAL MANAGEMENT

 

We use the Stephens-Sanders classification system and treatment protocol for calcaneal malunions, which is based on CT

evaluation.17 Type I malunions include a large lateral wall exostosis, with or without far lateral subtalar arthrosis. Type II malunions include a lateral wall exostosis and subtalar arthrosis involving the entire width of the joint. Type III malunions include a lateral wall exostosis, subtalar arthrosis, and malalignment of the calcaneal body resulting in significant hindfoot varus or valgus angulation (FIG 11A-C).

 

 

 

FIG 8 • Semicoronal CT image demonstrating subfibular impingement (white arrow) and posttraumatic arthritic changes in posterior facet (black arrows).

 

 

 

FIG 9 • Sagittal CT image demonstrating loss of calcaneal height (black arrows).

Preoperative Planning

 

The calcaneal malunion is evaluated with plain radiographs and CT scan and classified according to the Stephens-Sanders classification.17 Treatment is based strictly on malunion type:

 

Type I malunions are managed with a lateral wall exostectomy and a peroneal tenolysis.2,5,13

 

Type II malunions are managed with a lateral wall exostectomy, peroneal tenolysis, and a subtalar bone block arthrodesis, using the excised lateral wall as autograft.11

 

Type III malunions are managed with a lateral wall exostectomy, peroneal tenolysis, subtalar bone block arthrodesis, and a calcaneal osteotomy to correct hindfoot malalignment.7

 

The procedure requires use of a radiolucent table and a standard C-arm.

 

A pneumatic thigh tourniquet is used. The procedure should be completed within 120 to 130 minutes of tourniquet time to minimize potential wound complications.

 

 

 

 

FIG 10 • Semicoronal CT image of calcaneal malunion from fracturedislocation variant pattern (black arrows). This 25-year-old laborer had unfortunately been treated nonoperatively and rapidly developed posttraumatic arthritis.

 

 

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FIG 11 • Stephens-Sanders classification of calcaneal malunions. A. Type I malunion. B. Type II malunion. C. Type III malunion.

 

Positioning

 

The patient is placed in the lateral decubitus position on a beanbag. The lower extremities are positioned in a scissor configuration, such that the operative (“up”) limb is flexed at the knee and angles toward the distal posterior corner of the operating table, whereas the nonoperative (“down”) limb is extended at the knee and lies away from the eventual surgical field, which facilitates intraoperative fluoroscopy without interference from the nonoperative limb. Protective padding is placed beneath the contralateral limb for protection of the peroneal nerve, and an operating “platform” is created with blankets and foam padding to elevate the operative limb (FIG 12).

 

Alternatively, the prone position may be used in the event of bilateral procedures.

 

 

 

FIG 12 • Lateral decubitus position. Note scissor configuration of limbs to facilitate intraoperative fluoroscopy.

 

Approach

 

We use the extensile lateral approach for surgical management of the calcaneal malunion, regardless of malunion type. The lateral

calcaneal artery, typically a branch of the peroneal artery, supplies the majority of the full-thickness flap.1 Thus, strict attention to detail with respect to placement of the incision and gentle handling of the soft tissues is of paramount importance.

 

The planned extensile lateral approach is then outlined on the skin:

 

 

The incision begins approximately 2 cm proximal to the tip of the lateral malleolus, just lateral to the Achilles tendon and thus posterior to the sural nerve and the lateral calcaneal artery, and the vertical limb extends toward the plantar foot

 

The horizontal limb is drawn along the junction of the skin of the lateral foot and heel pad; this skin demarcation can be identified by compressing the heel. We substitute a gentle curve where these two lines combine to form a right angle, primarily to avoid apical necrosis. The horizontal limb also includes a gentle anterior curve along the skin creases distally, ideally ending over the calcaneocuboid articulation (FIG 13).

 

 

 

FIG 13 • Planned incision for extensile lateral approach.

 

 

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TECHNIQUES

• Extensile Lateral Approach

The limb placed on a sterile bolster and the incision begins at the proximal portion of the vertical limb, becoming full thickness

at the level of the calcaneal tuberosity—literally “straight to bone” while avoiding any beveling of the skin.9 Scalpel pressure is again lessened beyond the apical curve of the incision, and a layered incision is developed along the horizontal limb of the incision.

A full-thickness, subperiosteal flap is then raised starting at the apex, specifically avoiding use of retractors until a considerable subperiosteal flap is developed, in order to prevent separation of the skin from the underlying subcutaneous tissue (TECH FIG 1A).

The calcaneofibular ligament is sharply released from the lateral wall of the calcaneus, and the adjacent peroneal tendons are released from the peroneal tubercle through the cartilaginous “pulley” to avoid iatrogenic injury (TECH FIG 1B).

 

 

 

 

TECH FIG 1 • Extensile lateral approach. A. Note absence of retractors until a sizeable subperiosteal flap has been raised. B. Mobilization of peroneal tendons (white arrows). C. Gentle mobilization of flap along anterolateral wall of calcaneus. D. 1.6-mm K-wire retractors.

 

A periosteal elevator is then used to gently mobilize the tendons along the distal portion of the incision, which then exposes the anterolateral calcaneus. Thus, the peroneal tendons and sural nerve are contained entirely within the flap, and devascularization of the lateral skin is minimized (TECH FIG 1C).

 

Deep dissection continues to the sinus tarsi and anterior process region anteriorly, calcaneocuboid joint distally, and to the superior most portion of the calcaneal tuberosity posteriorly.

 

Three 1.6-mm Kirschner wires (K-wires) are placed for retraction of the subperiosteal flap: one into the fibula as the peroneal tendons are slightly subluxed anterior to the lateral malleolus, a second wire is placed in the talar neck, and a third wire is placed in the cuboid as the peroneal tendons are levered away from the anterolateral calcaneus with a periosteal elevator. Thus, each K-wire retracts its respective portions of the peroneal tendons and full-thickness skin flap (TECH FIG 1D).

• Lateral Wall Exostectomy

   

  A lateral wall exostectomy is completed for all three malunion types.

   

  Starting posteriorly, the A/O osteotomy saw blade is angled slightly medially relative to the longitudinal axis of the calcaneus, preserving more bone plantarly and thereby providing decompression of the subfibular impingement (TECH FIG 2A,B).

   

  Care is taken throughout the exostectomy to avoid violation of the talofibular joint: A small Bennett-type retractor is placed at the level of the posterior facet (TECH FIG 2B).

   

  67

   

  The exostectomy is continued to the level of the calcaneocuboid joint and is completed with an osteotome. The fragment is removed en bloc as a single fragment and is preserved in saline on the back table for later use as autograft (TECH FIG 2C).

   

   

   

  TECH FIG 2 • Lateral wall exostectomy. A. Intraoperative photo demonstrating vertical axis of limb (line A) and plane of lateral wall exostectomy (line B). B. Use of A/O osteotomy saw; note presence of small Bennett retractor protecting talofibular joint. C. Exostectomy fragment is removed en bloc for later use as autograft.

   

  The width of the exostectomy fragment is variable (˜10 to 15 mm) but is generally proportional to the extent of loss of calcaneal height and lateral wall expansion from the original injury, which reflects the amount of initial energy involved.

• Subtalar Bone Block Arthrodesis

   

  In patients with a type II or III malunion, the subtalar joint is gently mobilized with a small osteotome, carefully identifying the plane of the posterior facet.

   

  A laminar spreader is then placed and joint is meticulously débrided of any residual articular surface while preserving the underlying subchondral bone; we prefer to use a sharp periosteal elevator and pituitary rongeur.

   

  The joint is irrigated and multiple perforations are made in the subchondral surface with a 2.5-mm drill bit to stimulate vascular ingrowth. Highly concentrated platelet aspirate is then placed both within the joint and on the previously resected lateral wall fragment.

   

  The lateral wall fragment is placed within the subtalar joint as an autograft bone block; we prefer to place the laminar spreader posteriorly to better facilitate bone block placement (TECH FIG 3A).

   

  The fragment is positioned such that the widest portion of the autograft is oriented posteromedially to avoid varus malalignment (TECH FIG 3B).

   

  Any remaining voids within the subtalar joint are filled with supplemental allograft.

   

  With the subtalar joint held in neutral to slight valgus alignment, definitive stabilization is obtained with two large (6.5 to 8.0 mm) partially threaded cannulated screws placed from posterior to anterior in diverging fashion: The more lateral screw is placed in the talar dome, whereas the more medial screw is placed in the talar neck.

   

  A third screw may be placed extending from the anterior process region into the talar neck and head, avoiding violation of the talonavicular articulation (TECH FIG 4A-D).

   

  68

   

   

   

  TECH FIG 3 • Placement of autograft bone block. A. Note position of laminar spreader within subtalar joint posteriorly. B. Postoperative semicoronal CT image demonstrating proper orientation of autograft bone block (black triangle), with widest portion placed posteromedially.

   

   

   

  TECH FIG 4 • Definitive stabilization. A. Intraoperative fluoroscopic lateral view demonstrating diverging orientation of large cannulated screws posteriorly and supplemental screw traversing middle facet. B. Intraoperative fluoroscopic mortise view; note slight medial angulation to avoid violation of talofibular joint. C. Intraoperative fluoroscopic anteroposterior view; note transverse orientation of anterior screw avoiding violation of talonavicular joint (black arrows). D. Intraoperative fluoroscopic axial view; note neutral hindfoot alignment.

   

• Calcaneal Osteotomy

  69

   

  For those patients with a type III malunion, correction of angular malalignment in the calcaneal tuberosity is performed prior to implant placement.

   

   

  A Dwyer-type closing wedge osteotomy is performed for those with varus malalignment (TECH FIG 5). A medial displacement calcaneal osteotomy is used for those with valgus malalignment (rare).

   

  Because the plane of the osteotomy is nearly parallel to the plane of the posterior facet, the osteotomy and subtalar joint are stabilized simultaneously as described earlier.

   

   

   

  TECH FIG 5 • Calcaneal osteotomy. Dwyer closing wedge osteotomy for correction of varus malalignment in calcaneal tuberosity.

• Peroneal Tenolysis

   

  The K-wire retractors are removed, and the peroneal tendon sheath is incised along the undersurface of the subperiosteal flap over a length of 2 to 3 cm. A peroneal tenolysis is then completed.

   

  A Freer elevator is advanced within the tendon sheath to the level of the lateral malleolus proximally, thereby mobilizing the peroneal tendons.

   

  The competence of the superior peroneal retinaculum (SPR) is assessed by gently levering the Freer elevator forward while observing the overlying skin. The presence of an end point is indicative of an intact retinaculum; in the event of an incompetent SPR, the elevator will easily slide anterior to the lateral malleolus, with no demonstrable end point.

   

  The Freer elevator is then advanced within the tendon sheath distally to the cuboid tunnel.

• Superior Peroneal Retinaculum Repair

   

  In the event of an incompetent SPR, a separate 3 cm incision is made along the posterior border of the lateral malleolus, exposing the tendon sheath.

   

  With the peroneal tendons held reduced in the peroneal groove, one to two suture anchors are used to secure the detached SPR to bone (TECH FIG 6).

   

  Tendon stability is then reassessed using a Freer elevator in the same manner.

   

   

   

   

  TECH FIG 6 • SPR repair. Suture imbrication of incompetent SPR.

• Closure

   

  A deep drain is placed exiting proximally in line with the vertical limb of the incision.

   

  Deep no. 0 absorbable sutures are placed in interrupted, figureof-eight fashion, beginning with the apex of the incision and progressing to the proximal and distal ends. The sutures are temporarily clamped until all sutures have been passed, then hand tied sequentially, starting at the proximal and distal ends, and working toward the apex of the incision, so as to eliminate tension at the apex of the wound (TECH FIG 7).

   

  Because of the lateral decompression from the exostectomy, the flap should close fairly easily with minimal tension (despite restoration of calcaneal height).

   

  The skin layer is closed with 3-0 monofilament suture using the modified Allgöwer-Donati technique, again starting at the ends and working toward the apex (TECH FIG 7B).

   

  The tourniquet is deflated, and sterile dressings are placed, followed by a bulky Jones dressing and Weber splint.

   

   

  70

   

   

   

  TECH FIG 7 • Flap closure. A. Deep absorbable sutures placed and temporarily clamped. B. Skin closure using modified Allgöwer-Donati technique.

  PEARLS AND PITFALLS

   

  Lateral wall exostectomy

• Avoid violation of talofibular joint during lateral wall exostectomy.

• Gently place small Bennett-type retractor within subtalar joint at level of posterior facet to protect talofibular joint.

   

  Placing autograft bone block

  • Use of an additional lamina spreader at crucial angle of Gissane may be helpful in facilitating graft placement.

  • Release of deltoid ligament should be strictly avoided, as this destabilizes the ankle joint.

  • The peripheral margin of the fragment may need to be shaped slightly to prevent overhang and prominence laterally.

     

    Definitive stabilization

  • Avoid violation of talofibular joint by angling slightly medially during placement of guide pins (FIG 14A).

  • Fluoroscopic visualization of ankle joint prior to screw placement is of paramount importance (FIG 14B).

 

FIG 14 • Axial orientation of guide pins traversing posterior facet of subtalar joint. A. Intraoperative photo. B. Intraoperative fluoroscopic view. Note slight medial angulation to avoid violation of talofibular joint.

 

 

 

		Fracture- ▪ With fracture-dislocation variant patterns, posterolateral fragment is typically wedged within talofibular dislocation joint and is often associated with secondary lateral ankle instability. variant ▪ Mobilize subtalar joint prior to lateral wall exostectomy and excise prominent portion of posterolateral patterns fragment flush with remaining posterior facet articular surface. At conclusion of procedure, ankle joint should be stressed (varus force) under live fluoroscopy and lateral ligament reconstruction completed where necessary.
71

 

POSTOPERATIVE CARE

 

For type I malunions, the patient is converted to a prefabricated fracture boot at 2 weeks postoperatively. Weight bearing and range-of-motion exercises are initiated once the incision has fully sealed.

 

For type II or type III malunions, the patient is converted to a short-leg non-weight-bearing cast at 2 to 3 weeks and again at 6 to 7 weeks postoperatively. Weight bearing is not permitted until 10 to 12 weeks postoperatively, at which point radiographic union is confirmed.

 

The patient is then converted to a prefabricated fracture boot, and weight bearing is initiated. The patient is gradually transitioned to regular shoe wear and activity is advanced as tolerated thereafter.

 

OUTCOMES

Outcomes following open reduction and internal fixation (ORIF) of displaced intra-articular calcaneal fractures (when properly performed) are superior to those following initial nonoperative management of the fracture, even in the event of late posttraumatic subtalar arthritis.15

Surgery for a calcaneal malunion is therefore intended as a salvage procedure for pain relief and restoration of alignment. We previously reported our intermediate- to long-term results of this protocol4:

Ninety-three percent initial arthrodesis union rate

Ninety-three percent had neutral or slight valgus hindfoot alignment; 100% had plantigrade foot No statistical difference in outcome scores among the three malunion types

Significantly greater restoration of talocalcaneal height among type III malunions

 

 

COMPLICATIONS

Delayed wound healing, wound dehiscence, deep infection Arthrodesis delayed union or nonunion

Postoperative ankle stiffness

(Late) Lateral ankle (“sprain”) pain from coronal plane stresses applied to ankle joint (Late) Compensatory ankle joint arthritis (theoretical)

 

 

REFERENCES

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2. Braly WG, Bishop JO, Tullos HS. Lateral decompression for malunited os calcis fractures. Foot Ankle 1985;6:90-96.

    

    

3. Carr JB, Hansen ST, Benirschke SK. Subtalar distraction bone block fusion for late complications of os calcis fractures. Foot Ankle 1988;9:81-86.

    

    

4. Clare MP, Lee WE III, Sanders RW. Intermediate to long-term results of a treatment protocol for calcaneal fracture malunions. J Bone Joint Surg Am 2005;87:963-973.

    

    

5. Cotton FJ. Old os calcis fractures. Ann Surg 1921;74:294-303.

    

    

6. Crosby LA, Fitzgibbons T. Computerized tomography scanning of acute intra-articular fractures of the calcaneus. A new classification. 1990;72:852-859.

    

    

7. Dwyer FC. Osteotomy of the calcaneum for pes cavus. J Bone Joint Surg Br 1959;41:80-86.

    

    

8. Gallie WE. Subastragalar arthrodeses in fractures of the os calcis. J Bone Joint Surg 1943;25:731-736.

    

    

9. Gould N. Lateral approach to the os calcis. Foot Ankle 1984;4:218-220.

    

    

10. Isbister JF. Calcaneo-fibular abutment following crush fracture of the calcaneus. J Bone Joint Surg Br 1974;56:274-278.

     

     

11. Kalamchi A, Evans J. Posterior subtalar fusion. A preliminary report on a modified Gallie's procedure. J Bone Joint Surg Br 1977;59:287-289.

     

     

12. Kitaoka HB, Schaap EJ, Chao EY, et al. Displaced intra-articular fractures of the calcaneus treated non-operatively. Clinical results and analysis of motion and ground-reaction and temporal forces. J Bone Joint Surg Am 1994;76:1531-1540.

     

     

13. Magnuson PB. An operation for relief of disability in old fractures of the os calcis. JAMA 1923;80:1511-1513.

     

     

14. Myerson M, Quill GE Jr. Late complications of fractures of the calcaneus. J Bone Joint Surg Am 1993;75:331-341.

     

     

15. Radnay CS, Clare MP, Sanders RW. Subtalar fusion after displaced intra-articular calcaneal fractures: does initial operative treatment matter? J Bone Joint Surg Am 2009;91:541-546.

     

     

16. Sanders R, Fortin P, DiPasquale T, et al. Operative treatment in 120 displaced intraarticular calcaneal fractures. Results using a prognostic computed tomography scan classification. Clin Orthop Relat Res 1993;(290):87-95.

     

     

17. Stephens HM, Sanders R. Calcaneal malunions: results of a prognostic computed tomography classification system. Foot Ankle Int 1996;17:395-401.