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CME Article

Stepcut Calcaneal Lengthening Osteotomy in the Management of Stage IIB Adult-acquired Flatfoot Deformity: Surgical Technique and Review of Literature

Metikala, Sreenivasulu MD*; Mahmoud, Karim MD*; Young, Kelsey MD; Lee, Wonyong MD*; Wapner, Keith L. MD

Author Information
Techniques in Foot & Ankle Surgery: June 2020 - Volume 19 - Issue 2 - p 114-121
doi: 10.1097/BTF.0000000000000278

Abstract

CME OBJECTIVES

After completing this CME activity, the participant will be better able to:

  1. Explain the application of stepcut calcaneal lengthening osteotomy in adultacquired flatfoot deformity
  2. Compare the differences between conventional lateral column lengthening osteotomy and stepcut calcaneal lengthening osteotomy
  3. Describe the technical details of stepcut calcaneal lengthening osteotomy

HISTORICAL PERSPECTIVE

Adult-acquired flatfoot (AAFD) is a chronic debilitating condition and is most commonly caused by posterior tibial tendon (PTT) dysfunction.1–4 Johnson and Strom5 classified it into 3 stages and a fourth stage was added subsequently by Myerson.6 The stage II AAFD represents a failure of the PTT in a flexible planovalgus foot with absent degenerative changes at the subtalar joint. Stage IIB indicates forefoot abduction with significant uncoverage of the talonavicular (TN) joint in the axial plane. Medial displacement calcaneal osteotomy (MDCO) is one of the popular procedures that was described in its surgical management >40 years ago.7 It improves hindfoot valgus, shifts the vector arm of the gastrosoleus muscles medially and brings about a mechanically balanced foot.8 However, MDCO has not demonstrated the ability to maintain the correction in the long term and also has no influence on forefoot abduction.9–11 The concept of lateral column lengthening osteotomy (LCLO) then came into vogue to directly address forefoot abduction. It was first introduced by Evans in 1961 to correct calcaneovalgus deformity in children.12 He made a single coronal plane osteotomy through the anterior process of calcaneus 1.5 cm parallel and proximal to the calcaneocuboid (CC) joint. The osteotomy was distracted and a cortical autograft harvested from ipsilateral tibia was fitted into the gap. The same technique, in due course, was adapted to the adult flatfoot deformity correction to manage forefoot abduction, improve the TN coverage and restore the arch.13–16 However, LCLO is not without complications.17–22 Because of the axial lengthening, it triggers overloading of the lateral column and the CC joint resulting in lateral foot pain, fifth metatarsal stress fracture, and arthritis of the CC joint. Additional problems include resorption of the graft, loss of fixation, delayed union, nonunion, and donor-site morbidity. Griend,23 proposed stepcut calcaneal lengthening osteotomy (SCLO) as an alternative to LCLO with “Z”-shaped bone cuts centering the neck of the calcaneus. He fashioned a distal vertical cut along the dorsal half of calcaneal neck at 8 to 10 mm proximal to the CC joint followed by a proximal vertical cut at about the level of peroneal tubercle made through the plantar half of the body of the calcaneus. The final full-thickness transverse was made joining the previous 2 limbs completing the “Z”-design. The improvement in abduction at the forefoot was achieved primarily by axial rotation of distal fragment instead of translation thus reducing the related adverse effects of lateral column overload. However, this procedure was always coupled with MDCO which in fact was performed first through an oblique lateral incision placed parallel and posterior to the peroneal tendons. The SCLO was then added through a separate horizontally placed lateral incision at a distal level and was filled with allograft or resected bone from the overhang of MDCO. Screws were used to stabilize both osteotomies.

The senior author (K.L.W.) proposed a modified technique of SCLO that can correct forefoot abduction and hindfoot valgus deformities through a single incision without an additional MDCO. No major changes were made in the distal-dorsal cut whereas the proximal-plantar bone cut was moved to a more posterior location just past the peroneal tubercle. This adjustment had created a sufficient lever arm with an optimum magnitude of rotation of posterior tuberosity fragment correcting hindfoot valgus. The resultant osteotomy gaps at both levels were fitted with titanium metal wedges instead of auto/allograft products with no further internal fixation. This modified technique was presented at one of the American Orthopaedic Foot and Ankle Society annual meetings as a video demonstration of tips and tricks.

INDICATIONS AND CONTRAINDICATIONS

The classic indication for SCLO is symptomatic stage IIB AAFD secondary to PTT insufficiency that failed to improve with nonoperative treatment. It is usually combined with other soft tissue rebalancing procedures such as flexor digitorum longus tendon transfer, gastroc recession or achilles tendon lengthening, and repair of medial static restraints.

Contraindications include fixed deformities, symptomatic arthritis, vascular insufficiency, active infection, and Charcot arthropathy. Relative contraindications include osteopenia or osteoporosis, large cystic lesions in the calcaneus, and patients who cannot remain non–weight-bearing in the early postoperative period.

PREOPERATIVE PLANNING

As a routine, the preoperative planning starts with a thorough history and physical examination. Emphasis is also paid on the contributing factors like obesity, smoking, seronegative/inflammatory arthropathy, previous surgery/injury, and steroid usage. Clinical examination is conducted in both sitting and standing positions to better understand the overall alignment of both lower extremities and the magnitude of deformities. The presence of hindfoot valgus and a “too many toes” sign consistent with forefoot abduction should be noted. The PTT is palpated for swelling, tenderness and the inversion muscle strength is recorded. The flexibility of the tibiotalar, hindfoot, midfoot and forefoot joints are recorded along with range of motion. The hindfoot is brought into neutral before the assessment of forefoot alignment. Deformities such as supination of forefoot or instability of medial column would warrant additional medial column stabilization procedures. Attention to check the vascularity and sensation of the lower extremity is mandatory. Standing radiographs of the foot and ankle are reviewed to evaluate the magnitude of deformity in orthogonal views using standard radiologic parameters. The radiographs are also scrutinized for the evidence of arthritis and additional deformities that might influence the treatment plan. Additional imaging such as magnetic resonance imaging is utilized to better understand the PTT pathology, identify the spring ligament tear, or to confirm the diagnosis in questionable situations. Nonoperative treatment with a custom brace for 3 to 4 months is the standard initial treatment along with activity modifications and physical therapy (PT).24 A short course of oral anti-inflammatory medication and protected immobilization in a cast may be appropriate for more acute presentations. Surgery is considered for patients who do not respond to adequate conservative measures. Finally, consent is obtained from the patient educating the risks and benefits of the procedure, the usual perioperative plan including the details of the initial non–weight-bearing status and the PT visits.

SURGICAL TECHNIQUE

The procedure is performed under general anesthesia supplemented with a regional popliteal block. The patient lies in a supine position on the operation table with a sandbag under the ipsilateral gluteal region to allow slight internal rotation of the lower extremity. A pneumatic thigh tourniquet is applied and the lower extremity is prepped and draped in a standard fashion. A longitudinal incision is placed along the lateral aspect of the hindfoot from the tip of the lateral malleolus to the CC joint. The subcutaneous dissection is done to identify the sural nerve. It is adequately mobilized with a circumferential sleeve of fat to minimize postoperative adhesions. The inferior peroneal retinaculum and the individual tendon sheaths of peroneus longus and brevis are opened to mobilize the tendons. A large peroneal tubercle, if present, is resected. Three soft tissue windows are routinely developed to clearly visualize the working portion of the lateral calcaneus. The first window is made between sural nerve and peroneus brevis tendon, the second one between peroneus brevis and peroneus longus tendons, and the final third window is established between peroneus longus and plantar heel pad. The Z-design of SCLO is marked with a marking pen or diathermy pin. First, a distal-dorsal arm is created using a sagittal saw at 1.5 cm proximal and parallel to the CC joint by working through the first window (Figs. 1, 2). Care is taken to exit the bone cut between anterior and middle articular facets of the calcaneus medially. It is followed by the second vertical arm fashioned along the plantar half of calcaneus at 2.5 cm proximal to the previous bone cut and is performed through the third window. The final transverse bone cut along the full thickness of calcaneus and is made connecting the previous 2 limbs by working through the second window. The woodpecker technique is practiced throughout the osteotomy while the foot is rested in plantar flexion and inversion to move the neurovascular bundle away from the medial calcaneus. Once all 3 bone cuts are completed, the proximal-plantar arm is gently opened by inserting a special heart-shaped lateral column spreader designed by the senior author (K.L.W.). It is equipped with broad paddles to prevent digging into the cancellous bone during the distraction and is particularly helpful in the osteoporotic situation. This distraction at the proximal level results in an indirect opening of the distal osteotomy with medial rotation of the anterior process correcting forefoot abduction at the TN joint. At the same time, the posterior tuberosity fragment is also rotated in a medial direction together with the achilles insertion correcting the valgus of the hindfoot (Fig. 2B). No attempt is made to directly open the distal-dorsal osteotomy due to the risk of fracturing the anterior process of calcaneus. Also, the distraction at the proximal osteotomy is progressed in small increments until the satisfactory visual restoration of the medial arch and fluoroscopic improvement of TN coverage. The size of the implant corresponds to the gap created at the osteotomy which can be measured directly using a ruler. Trial wedges are inserted for further verification with the distractor still in place at the proximal arm, an appropriately sized highly porous titanium wedge is now inserted in the distal osteotomy gap. The distractor is then removed from the proximal osteotomy, and is replaced with a second suitable titanium wedge (Fig. 3). A synthetic bone graft (beta-tricalcium phosphate) is frequently used to coat these metal wedges before insertion in patients with poor bone stock. This Z-design with the metal wedges inserted in the osteotomy gaps is a stable construct and no additional internal fixation is necessary. The overhanging bone edges that result due to the rotation of bone fragments are tamped down to ensure smooth gliding of the peroneal tendons (Fig. 2B). Nonunion is rare due to quick healing of the broad cancellous kissing surfaces of the transverse arm. Likewise, loss of correction in the long-term is rare due to the placement of metal wedges, which resist resorption, unlike auto/allograft products. The adjuvant procedures such as percutaneous tendoachilles lengthening, debridement of PTT and flexor digitorum longus tendon transfer to the medial part of navicular bone are performed as per the necessity. Final fluoro images are obtained and the wounds are closed in layers. The anteroposterior and lateral weight-bearing radiographs of flexible flatfoot deformity in a 70 years woman due to PTT dysfunction in conjunction with asymptomatic ankle arthritis are depicted in Figure 4. Her follow-up images at 1-year postoperative demonstrate healing of osteotomies, stable hardware and restoration of TN angle and calcaneal pitch angle (Fig. 5).

FIGURE 1
FIGURE 1:
The geometry of the Z-design of modified stepcut calcaneal lengthening osteotomy in a left calcaneus bone model. A, The distal arm is placed through the dorsal half of the anterior tubercle at 1.5 cm proximal and parallel to the calcaneocuboid joint, the plantar arm is made at ∼2.5 cm proximal to the distal arm just past the peroneal tubercle and finally, the transverse arm is made connecting the 2 vertical cuts. B, Deformity correction at forefoot and hindfoot is achieved by medial rotation of anterior tubercle and posterior tuberosity.
FIGURE 2
FIGURE 2:
Axial view of modified stepcut calcaneal lengthening osteotomy in the same bone model. A, The placement of the distal dorsal arm through the anterior portion of calcaneus exiting between anterior and middle articular facets medially. B, Medial rotation of osteotomy fragments create a lateral overhang of bone edges that require resection to obtain a smooth bed for the peroneal tendons.
FIGURE 3
FIGURE 3:
Intraoperative image of the left foot depicting the metal wedges inserted at the distal-dorsal and plantar-proximal vertical arms of the Z-osteotomy.
FIGURE 4
FIGURE 4:
Weight-bearing AP and lateral images of flatfoot deformity in a 70-year woman with asymptomatic ankle arthritis. AP indicates anteroposterior.
FIGURE 5
FIGURE 5:
Postoperative follow-up images of the same patient at 1-year with healing of osteotomies, stable hardware and restoration of talonavicular angle and calcaneal pitch angle.

POSTOPERATIVE MANAGEMENT

A well-padded bulky posterior splint is applied with the ankle in plantar flexion and inversion. The patient is instructed to elevate the limb, apply ice and avoid weight-bearing. Skin sutures are removed at 2 weeks and a non–weight-bearing short leg cast is applied for 2 more weeks. At the end of 4 weeks, radiographs are obtained and the patient is placed in a walking boot allowing partial weight-bearing. Standing radiographs are performed at the end of 8 weeks and full weight-bearing within the boot is encouraged in parallel with the range of motion exercises. At the 12-week mark, the weight-bearing radiographs are repeated to confirm osteotomy healing and the patient is gradually weaned off the boot. PT is then commenced for improving the range of motion, proprioception, gait training, and muscle strengthening aiming for a gradual return to full activities.

COMPLICATIONS

The common problems with this technique include injury to the sural nerve and peroneal tendons. The sural nerve is particularly vulnerable and hence should be actively sought and carefully mobilized with a sleeve of fat to minimize postoperative neuritis or neuroma. The diligent development of 3 soft tissue windows, as stated, is of immense help to clearly visualize the working portion of the lateral surface of calcaneus without excess retraction of the nerve or tendons. Peroneal tendonitis can also occur due to irritation of the overhanging shelf of the bone and can be circumvented by punching it down to obtain a smooth gliding surface. The tibial neurovascular bundle is at potential risk due to plunging the saw blade off the medial cortex. Having good control over the sagittal saw, using the woodpecker technique and leaving the foot in plantar flexion and inversion with no counter pressure can mitigate this serious complication. Following the creation of all 3 bone cuts, the mobilization of bone fragments can be difficult and often leads to frustration. Iatrogenic fractures are likely if the fragments are forced to rotate without proper mobilization. The common reason is an incomplete bone cut, especially at the 2 elbows of the Z-design, which can be prevented by a slight overlapping of the bone cuts. Also, the sagittal saw is employed for the entire portion of the bone cut instead of relying on an osteotome to break the final bit of the medial cortex thus avoiding spiky edges that can limit rotation of the bone fragments. Intraoperative fracture of anterior process of the calcaneus is another problem and can be mitigated by the placement of osteotomy at 1.5 cm proximal and parallel to the CC joint. It thus leaves a sizeable piece of the anterior process, strong enough to resist splintering when the metal wedge is tamped in. Furthermore, damage to the anterior and/or middle facets of the calcaneus should be avoided to prevent step off, arthrofibrosis and sinus tarsi pain. Under correction of hindfoot valgus is a possibility if the proximal-plantar arm is not made at the right level. It is highly recommended to place this cut at about 2.5 cm proximal to the distal arm just past the level of peroneal tubercle to create sufficient lever arm and facilitate medial rotation of tuberosity fragment over an optimum radius. The more anterior location such as distal to peroneal tubercle produces a shorter lever arm necessitating MDCO as an additional procedure.

RESULTS

Griend in 2008, presented 8 patients with flexible flatfoot deformity that underwent a short SCLO in combination with MDCO. All had complete healing of the double osteotomies with no reported symptoms of lateral column overload. However, no long term follow-up was available except in 2 patients who maintained correction at 2 years. In 2012, the senior author (K.L.W.) presented the aforementioned technique of modified SCLO at the American Orthopaedic Foot and Ankle Society annual meeting as a video demonstration of tips and tricks. Scott and Berlet25 endorsed this idea of isolated Z calcaneal osteotomy as a replacement to the traditional dual calcaneal osteotomy (MDCO+LCLO). The same group, later on, adopted a reverse Z-design switching the direction of the distal and proximal vertical cuts and retrospectively reviewed their outcomes on 16 patients.26 Statistical improvement in both the radiologic parameters and clinical function scores were reported at a mean 2-year follow-up. In 2015, Demetracopoulos et al27 retrospectively reviewed the outcomes of 37 patients with stage II AAFD that underwent stepcut calcaneal osteotomy and included MDCO in all of them with excellent outcomes. The same group republished in 2018 comparing the SCLO with LCLO.28 At an average 2-year follow-up, the authors reported significant improvements in the TN coverage and mean calcaneal pitch angle in the SCLO group besides quicker healing of osteotomy. More nonunions and hardware removals were observed in the LCLO group whereas peroneal tendons issues were found to be associated with the stepcut group.

POSSIBLE CONCERNS/FUTURE OF THE TECHNIQUE

The successful execution of the modified version of SCLO requires strict adherence to the surgical technique. The problems associated with the sural nerve injury and damage to the peroneal tendons can be disabling. The diligent dissection and development of soft tissue windows can easily provide adequate access to the working portion of the calcaneus. The accurate placement of the osteotomy arms is of paramount importance. The gradual distraction of proximal osteotomy using the special distractor can precisely dial the correction. The utilization of the metal wedges can maintain the correction even in the long-term. These newer highly porous titanium metal wedges have increasingly been used in the current foot and ankle surgery sparing the patients from the complications of autograft and allograft products. Their applications are expected to expand in the future with further developments in the design. Also, usage of biologics such as beta-tricalcium phosphate can be a useful adjunct in patients with poor bone stock. Further studies regarding the long-term outcome of these products are required.

In conclusion, the modified Z-design of SCLO with distal-dorsal and proximal-plantar arms is an option to address the forefoot abduction and hindfoot valgus in the surgical management of stage IIB AAFD. It can be performed by a single incision, and serves as an alternative technique for LCLO, obviating an additional MDCO. The procedure has a small learning curve that can be accomplished by paying meticulous attention to the surgical technique.

CME QUESTIONS

  1. A 64-yr woman comes to the office with a gradual onset of pain along the medial aspect of the hindfoot for 6-8 weeks. She has a collapsed medial longitudinal arch with hindfoot valgus and forefoot abduction. She could not perform a single-limb heel rise. Power testing reveals significant weakness of inversion. Weightbearing radiographs reveal negative Meary’s angle with 5° of calcaneal pitch angle. Which of the following statements is NOT CORRECT in the management of her condition?
    • Needs immediate surgery with FDL tendon transfer and calcaneal osteotomy
    • Needs a custom-made brace with a medial post
    • Needs a short course of anti-inflammatories and cast if the symptoms are acute
    • Needs an MRI scan
  2. Which of the following is NOT TRUE about Adult Acquired Flat Foot Deformity (AAFD) Stage IIB?
    • Pain is distributed along the posterior tibial tendon
    • It is usually associated with limitation of inversion and eversion
    • Clinical examination shows positive “too many toes” sign
    • It is often associated with equinus contracture
  3. Before considering stepcut calcaneal lengthening osteotomy, one should ensure that
    • The patient has flexible subtalar joint with no evidence of symptomatic arthritis
    • Failed conservative treatment for 3-4 months
    • Has both forefoot abduction and hindfoot valgus
    • All of the above
  4. What is the main advantage of stepcut lengthening osteotomy over conventional lateral column lengthening osteotomy?
    • Stepcut osteotomy is done through small incisions
    • It offers the correction of deformity by rotation of fragments
    • It has less possibility of peroneal tendon irritation
    • It is a relatively quick procedure
  5. Regarding the surgical technique of stepcut calcaneal lengthening osteotomy, which of the following statements is NOT CORRECT?
    • Diligent development of soft-tissue windows is important to prevent irritation of the sural nerve and peroneal tendons
    • The distal bone cut is made through the dorsal half of the anterior calcaneus
    • The distal bone cut is distracted directly using a laminar spreader
    • Nonunion is rare

REFERENCES

1. Key JA. Partial rupture of the tendon of the posterior tibial muscle. J Bone Joint Surg Am. 1953;35-A:1006–1008.
2. Jahss MH. Spontaneous rupture of the tibialis posterior tendon: clinical findings, tenographic studies, and a new technique of repair. Foot Ankle. 1982;3:158–166.
3. Mann RA, Thompson FM. Rupture of the posterior tibial tendon causing flat foot. Surgical treatment. J Bone Joint Surg Am. 1985;67:556–561.
4. Funk DA, Cass JR, Johnson KA. Acquired adult flat foot secondary to posterior tibial-tendon pathology. J Bone Joint Surg Am. 1986;68:95–102.
5. Johnson KA, Strom DE. Tibialis posterior tendon dysfunction. Clin Orthop Relat Res. 1989;239:196–206.
6. Myerson MS. Adult acquired flatfoot deformity. Treatment of dysfunction of the posterior tibial tendon. J Bone Joint Surg Am. 1996;78-A:780–792.
7. Koutsogiannis E. Treatment of mobile flat foot by displacement osteotomy of the calcaneus. J Bone Joint Surg Br. 1971;53:96–100.
8. Myerson MS, Badekas A, Schon LC. Treatment of stage II posterior tibial tendon deficiency with flexor digitorum longus tendon transfer and calcaneal osteotomy. Foot Ankle Int. 2004;25:445–450.
9. Niki H, Hirano T, Okada H, et al. Outcome of medial displacement calcaneal osteotomy for correction of adult-acquired flatfoot. Foot Ankle Int. 2012;33:940–946.
10. Hadfield MH, Snyder JW, Liacouras PC, et al. Effects of medializing calcaneal osteotomy on Achilles tendon lengthening and plantar foot pressures. Foot Ankle Int. 2003;24:523–529.
11. Bolt PM, Coy S, Toolan BC. A comparison of lateral column lengthening and medial translational osteotomy of the calcaneus for the reconstruction of adult acquired flatfoot. Foot Ankle Int. 2007;28:1115–1123.
12. Evans D. Calcaneo valgus deformity. J Bone Joint Surg Br. 1975;57:270–278.
13. Hintermann B, Valderrabano V, Kundert HP. Lengthening of the lateral column and reconstruction of the medial soft tissue for treatment of acquired flatfoot deformity associated with insufficiency of the posterior tibial tendon. Foot Ankle Int. 1999;20:622–629.
14. Sangeorzan BJ, Mosca V, Hansen ST. Effect of calcaneal lengthening on relationships among the hindfoot, midfoot, and forefoot. Foot Ankle. 1993;14:136–141.
15. DuMontier TA, Falicov A, Mosca V, et al. Calcaneal lengthening: investigation of deformity correction in a cadaver flatfoot model. Foot Ankle Int. 2005;26:166–170.
16. Kitaoka HB, Kura H, Luo ZP, et al. Calcaneocuboid distraction arthrodesis for posterior tibial tendon dysfunction and flatfoot: a cadaveric study. Clin Orthop Relat Res. 2000;381:241–247.
17. Ellis SJ, Williams BR, Garg R, et al. Incidence of plantar lateral foot pain before and after the use of trial metal wedges in lateral column lengthening. Foot Ankle Int. 2011;32:665–673.
18. Tien TR, Parks BG, Guyton GP. Plantar pressures in the forefoot after lateral column lengthening: a cadaver study comparing the evans osteotomy and calcaneocuboid fusion. Foot Ankle Int. 2005;26:520–525.
19. Thomas RL, Wells BC, Garrison RL, et al. Preliminary results comparing two methods of lateral column lengthening. Foot Ankle Int. 2001;22:107–119.
20. Deland JT, Otis JC, Lee K-T, et al. Lateral column lengthening with calcaneocuboid fusion: range of motion in the triple joint complex. Foot Ankle Int. 1995;16:729–733.
21. Hyer CF, Lee T, Block AJ, et al. Evaluation of the anterior and middle talocalcaneal articular facets and the Evans osteotomy. J Foot Ankle Surg. 2002;41:389–393.
22. Davitt JS, Morgan JM. Stress fracture of the fifth metatarsal after Evans’ calcaneal osteotomy: a report of two cases. Foot Ankle Int. 1998;19:710–712.
23. Griend RV. Lateral column lengthening using a “Z” osteotomy of the calcaneus. Tech Foot Ankle Surg. 2008;7:257–263.
24. Chao W, Wapner KL, Lee TH, et al. Nonoperative management of posterior tibial tendon dysfunction. Foot Ankle Int. 1996;17:736–741.
25. Scott RT, Berlet GC. Calcaneal Z osteotomy for extra-articular correction of hindfoot valgus. J Foot Ankle Surg. 2013;52:406–408.
26. Ebaugh MP, Larson DR, Reb CW, et al. Outcomes of the extended Z-cut osteotomy for correction of adult acquired flatfoot deformity. Foot Ankle Int. 2019;40:914–922.
27. Demetracopoulos CA, Nair P, Malzberg A, et al. Outcomes of a stepcut lengthening calcaneal osteotomy for adult-acquired flatfoot deformity. Foot Ankle Int. 2015;36:749–755.
28. Saunders SM, Ellis SJ, Demetracopoulos CA, et al. Comparative outcomes between stepcut lengthening calcaneal osteotomy vs. traditional Evans osteotomy for stage IIB adult-acquired flatfoot deformity. Foot Ankle Int. 2018;39:18–27.
Keywords:

adult-acquired flatfoot; calcaneal osteotomy; Z-cut; posterior tibial tendon dysfunction; lateral column lengthening

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