Limb Lengthening 0030-5898/91 $0.00 + .20
Lower Extremity Lengthening
by Wagner's Method
and by Callus Distraction
Mark T. Dahl, MD, * and
David A. Fischer, MD†
* Director of Limb Length
Clinics, Shriner's Hospital for Crippled Children, Minneapolis,
Gillette Children's Hospital and St. Anthony Orthopaedic Clinic,
St. Paul, Minnesota
† Orthopaedic Consultants, Minneapolis, Minnesota
Orthopedic Clinics of North AmericaóVol. 22, No. 4, October
1991
Surgical equalization of limb length discrepancy can be achieved through a variety of techniques.(1,2,5,9,10,12,14) Discrepancies of less than 5 cm can be treated adequately by contralateral epiphysiodesis during growth or by closed femoral shortening at maturity. Larger discrepancies, or those in short-statured individuals, can be managed by lengthening the involved limb.
The high incidence of complications associated with lengthening procedures is well documented in the literature. Chauchoix and Morel (2) reported a 29% complication rate in femoral lengthenings performed by a "onestage" method. Coleman (3,4) cited an 81% complication rate in 73 patients who underwent tibial lengthening using the Anderson apparatus. Problems or complications were present in 44.8% of Wagner's femoral lengthening patients (1); however, Hood and Riseborough (8) reported a 92% complication rate with the Wagner technique. DeBastiani et al (5) reported a 14% complication rate using the callus distraction technique, whereas Guidera et al (7) recently reported 60 complications in 74 patients using the Orthofix device.
The contributions of Ilizarov (9) and DeBastianiv (5) have been valuable in developing a less invasive method of distraction osteogenesis. Improvements in external fixation, including unilateral or multiplanar fixators with half or full pins, (6) and circular frames with tensioned K-wires, (9) have resulted in greater technical abilities.
Our initial experience with leg lengthening involved the Wagner method. We found substantial complications and significant morbidity with the multiple procedures necessary to achieve lengthening. This prompted us to consider alternative methods of limb elongation. We began using the callus distraction technique in 1985 hoping to reduce the number of operations for each patient.
This study compares the results of two methods for lower extremity lengthening: the Wagner and the callus distraction. The application of three types of half-pin fixators is discussed. Particular emphasis is focused on complications, because they can be substantial and are often inadequately discussed. A comparison of operative morbidity associated with the two techniques is discussed.
METHODS
Fifty-three patients underwent 64 segment lengthenings between
1980 and 1990 at the Twin Cities Shriner's Hospital for Crippled
Children and Gillette Children's Hospital (30 boys, 23 girls).
The mean age at operation was 11 years, with a range of 5 to 17
years. Twenty-five segments were lengthened by the Wagner method
and 39 by callus distraction. Seven femurs and tibias were lengthened
simultaneously. Three repeat lengthenings of the same segment
were performed. Patient follow-up ranged from 1 to 10 years (mean
of 4 years).
Inequalities were congenital in 28 limbs and acquired in 25. One of three half-pin external fixators was used (Table 1): Wagner,s Fixator; Orthofix Dynamic Axial Fixator; Ace-Fischer Fixator.
All patients had preoperative scanograms. Skeletal age and prediction of final discrepancy were determined using Mosleyís method. (11) Preoperative range of motion, angular and rotational deformities, gait pattern, muscle strength, neurologic status, and psychologic preparedness were recorded.
Axial alignment and joint stability were achieved by performing the following osteotomies prior to lengthening: (1) one pelvic osteotomy for acetabular insufficiency; (2) one fibular epiphysiodesis; (3) three tibial osteotomies; and (4) five femoral osteotomies.
Two groups of patients were established for the retrospective analysis, those treated with the Wagner method and those treated by the DeBastiani technique. Complication rates and number of procedures were tabulated.
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TECHNIQUE OF LENGTHENING |
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| SEGMENT/DEVICE |
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| Femur | ||
Wagner |
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Orthfix |
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Ace-Fischer |
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| Tibia | ||
Ace-Fischer |
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| Totals |
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Wagner Technique
Wagner's technique (12,13)
involves the placement of a half-pin external fixation device
on the intact bone that is to be lengthened. An open osteotomy
is performed with immediate distraction of approximately 1.5 mm.
The bone is lengthened 1.5 mm per day in graduated stages by the
patient. Subsequent to completion of the distraction, the osteotomy
is internally fixed with a plate, and the gap is grafted with
autologous cancellous bone.
Twelve femoral and 13 tibial lengthenings were performed by Wagnerís open osteotomy technique (Fig. 1). In the 12 femoral procedures, the Wagner device was used for fixation in seven, the Orthofix in four, and the Ace-Fischer in one (see Table 1). Thirteen tibial lengthenings were performed using Wagnerís technique in conjunction with the Ace-Fischer multiplanar half-pin external fixator. Three pins were used both above and below the osteotomy site at 45-degree positions, creating multiplanar fixation. Plate osteosynthesis and cancellous bone grafting were done routinely at the completion of distraction. This was not necessary in three femoral and two tibial lengthenings because adequate spontaneous healing occurred upon completion of the distraction.
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Callus Distraction
(DeBastiani) Technique
Twenty-four femoral and 15 tibial lengthenings were performed using DeBastianiís technique of callus distraction (Fig. 2). (5) The Orthofix frame was used in all femoral lengthenings. The Ace-Fischer frame was used in the tibial lengthenings because it provided multiplane fixation. Following corticotomy, distraction was initiated when callus was evident on the radiograph (day 10-14). The segment was lengthened 0.25 mm, four times daily. The static phase began at completion of distraction. Dynamization was achieved by loosening the body locking screw when new cortical bone was evident. Femoral fixators were removed in the outpatient department with no anesthesia. Tibial frames were removed under anesthesia, which was necessary to remove the transfixion screws.
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RESULTS
The mean increases in length for both methods are presented in Table 2. The mean femoral and tibial lengths gained by the Wagner technique were 5.1- 5.4 cm, respectively. This represented a 12% (femoral) and 14% (tibial) increase over initial segment length. The mean amount of lengthening obtained by callus distraction was 4.9 cm for the femur (18% gain) and 4.5 cm for the tibia (16% gain). In the segments lengthened by callus distraction, the callus distraction healing index was calculated by dividing the total fixator time (days) by the total amount of lengthening achieved (centimeters). The healing index was 38 for the femur and 41 for tibia (mean was equal to 40).
| TECHNIQUE | MEAN INCREASE | RANGE (cm) | % INCREASE |
| Wagner | |||
| Femur | 5.1 | (3.0 - 8.0) | 12 |
| Tibia | 5.4 | (4.5 - 7.0) | 14 |
| Callus Distraction | |||
| Femur | 4.9 | (2.2 - 8.0) | 18 |
| Tibia | 4.5 | (4.2 - 4.7) | 16 |
Complications
Sixty-six complications
occurred in 64 segments (Table 3). Thirty-seven occurred in 19
of the segments lengthened by Wagner's method (six segments uncomplicated)
and 29 occurred in 27 of the segments lengthened by callus distraction
(12 segments uncomplicated).
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| COMPLICATION |
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| Minor sepsis |
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| Deep Sepsis |
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| Pin Loosening |
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| Skin Slough |
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| Fracture |
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| Premature Consolidation |
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| Angulation |
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| Knee subluxation |
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| Hip subluxation |
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| Nonunion |
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| Neurological deficit | ||
Temporary |
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Permanent |
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Totals |
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Infection
Sepsis was considered minor if temporary drainage was expressed from the pin sites and successfully treated with oral antibiotics, with increased pin care, and occasionally by incising the pin site under local anesthesia (23 patients). Deep sepsis (osteomyelitis) developed in five patients, all of whom were treated using Wagnerís technique. One case was discovered 3 years postoperatively, at the time of elective femoral plate removal. This patient was successfully treated with debridement and antibiotics.
Four other cases occurred secondary to pinsite contamination of the lengthened segment and were associated with osteosynthesis. Plate removal and subsequent reapplication were necessary in one patient, and operative debridement was performed in three patients. Infection did not result in loss of length or delayed union in any of the patients.
Pin Loosening
Five pin sites (five Wagner, four callus distraction) developed loosening. Early extraction of the pins was required in the case of the Wagner fixator. Further advancement of the tapered pin was performed twice, but excessive insertion was necessary to gain pin stability. Two tapered pins were removed early in the callus distraction group.
Skin Slough
One Wagner osteotomy site incision underwent full-thickness skin necrosis in an area (one by 4 cm) in which two previous incisions had been made. The skin slough healed by secondary intention with local wound care.
Fracture
Five fractures occurred in patients who underwent the Wagner technique: one following premature plate removal, a second after fixator removal with immature callus formation, and a third through a pin site 2 years after osteosynthesis and plate removal. Two tibias fractured soon after plate removal despite brace protection.
Three femoral fractures occurred in the callus distraction group, all within 1 week of fixator removal. Three features were common to each: lengthening-site varus, severe osteopenia, and knee stiffhess.
Premature Consolidation
Premature fibular healing occurred in one tibial lengthening using the callus distraction method. Additional 1-cm excision of the fibula allowed further lengthening. One femoral lengthening began to consolidate prematurely but separated spontaneously with continued lengthening.
Angulation
Two patients with fibular hemimelila were noted to have progressive anterior bowing of their tibias following removal of plates. Both patients were operated on using the Wagner technique. Osteotomies to correct the angular deformities were performed. Two patients who underwent femoral callus lengthenings had varus deformities that required a modification of fixation under anesthesia.
Subluxation
Knee subluxation occurred in five patents, four of whom with congenitally deficient limbs had simultaneous femoral and tibial lengthenings. Two resolved when the lengthening was stopped; one required hamstring lengthening, and two persisted with a mild degree of subluxation. Two hips subluxed; both had potential instability associated with prior hip sepsis. One resolved spontaneously with discontinuation of lengthening, and the second was treated with pelvic osteotomy and subsequent relengthening. Subluxation appeared to occur independent of which method of lengthening was used.
Nonunion
Three cases of nonunion occurred in tibial lengthenings with Wagnerís method. All healed after a second autogenous cancellous bone graft.
Neurologic Deficit
Four neurologic complications occurred. All involved paralysis of the extensor hallucis longus muscle in association with tibial lengthenings. The one permanent palsy was noted immediately following operation. The three transient palsies occurred during lengthenings greater than 15% and resolved upon discontinuation of lengthening.
Fixator Performance
Cantilever effect with varus deformity has been recognized as a disadvantage of uniplanar fixators. The greater medial and anterior musculature on the femur, and lateral and posterior musculature on the leg, contribute to varus and valgus deformities of these segments during lengthening. The Ace-Fischer frame, with its multiplanar abilities, was used on the tibial lengthenings to prevent valgus deformity. In its single femoral use, pin spread was not sufficient to control the segments, which resulted in a 14-degree anterolateral bow. Angulation was measured at each lengthening site and was considered to be excessive if greater than 10 degrees.
Femoral varus with the Wagner external fixator averaged 6 degrees and did not result in residual deformity because osteosynthesis was used in conjunction with this fixator. The Orthofix fixator resulted in an average of 4 degrees of varus, increasing with lengthening greater than 6 cm with greater pin length.
Five femoral lengthenings were performed following acute intraoperative angular corrections of less than 20 degrees. The latent period was extended 5 days in each case.
We observed no instances of tibial fixation failure resulting in loss of position. Two cases with angular tibial deformity were corrected with the Ace-Fischer fixator prior to the initiation of lengthening.
Operations per Segment
Ninety-one operations
were performed on the 25 segments lengthened by Wagnerís
technique (3.64 operations per segment lengthened). Sixty-two
operations were performed on the 39 segments lengthened by callus
distraction (1.59 operations per segment lengthened).
DISCUSSION
Sixty-four lengthenings of the femur and tibia by the Wagner and callus distraction methods were performed. All achieved clinical and radiographic union. The average percentage of length gained by the Wagner and callus distraction methods was similar. Complication rates were fewer and less severe with callus distraction. The number of operations, days of hospitalization, and length of treatment were less in patients treated with the callus distraction method as well.
Three types of external fixation were used. The Wagner fixator was used in our initial seven femoral lengthening patients and resulted in a slight varus deformation of the femur. The Orthofix fixator was used in 25 femoral lengthenings with varus deformation commonly occurring in lengthenings greater than 6 cm. We now use five- or six-pin fixation to minimize this. The Ace-Fischer fixator was used on the femur in one application and resulted in significant varus and anterior deformity. Its use on the tibia on 25 occasions did not result in deformity. The Ace-Fischer had the added advantage of allowing correction of pre-existing angular deformity in combination with the lengthening.
Our experience with these half-pin devices has been satisfactory, albeit with disadvantages inherent to each system. The surgeonís understanding of a systemís capabilities, combined with surgical experience, leads to success with each system.
Single-plane external fixation requires a high level of stiffness as well as the ability to dynamize the frame. Multiplane half-pin external fixation of the tibia diminishes the cantilever effect associated with single-plane fixation and allows for angular correction as well as dynamization.
Complications associated exclusively with the Wagner method and specifically osteosynthesis included: deep sepsis (five), late fracture (five), and nonunion (three). These complications can be eliminated by avoidance of plating and bone grafting. One case of premature fibular consolidation occurred with callus distraction. This can be avoided by adequate tibiofibular transfixion and more rapid initiation of lengthening.
Complications not unique to a particular method of lengthening include pin-site sepsis, knee and hip subluxations, and neurologic deficit. Pin-site sepsis has been improved by better insertion of the pin and by soft-tissue care. Knee subluxation can be minimized by avoiding significant simultaneous femoral and tibial lengthenings (particularly in the congenitally short limbs) and by maintaining full extension of the joint. Occurrence of postlengthening fracture can be minimized by avoiding axial deviation, osteopenia, and joint stiffness. The occurrence of these complications can be further diminished by careful patient selection, planning, and attention to the details of limb discrepancy surgery.
Complication rates are difficult to interpret. In our series of patients, 37 complications occurred in 25 segments lengthened by the Wagner technique (148%). Similarly, 29 complications occurred in 39 lengthenings using the callus distraction method, with a 74% complication rate.
A uniform method of defining and recording complications prospectively is greatly needed. We have defined a complication as any "unwanted event" and have devised a major and minor complication classification system for recording these events prospectively.
Based on our preliminary experience, callus distraction is a better method of limb lengthening than the Wagner technique and can reduce the frequency and severity of complications. It is recognized that limb lengthening by any method and with any device has the potential for significant complications.
SUMMARY
Fifty-three patients underwent 64 lengthenings of the femur or tibia by the Wagner (12,13) technique or by the callus distraction method. (5) Thirty-six femoral and 28 tibial segments were lengthened. Simultaneous lengthening of the femur and tibia was performed in seven limbs. Three segments underwent repeat lengthenings. The average length gained by the Wagner method was 5.1 cm in the femur and 5.4 cm in the tibia. Length gains by callus distraction were 4.9 cm in the femur and 4.5 cm in the tibia. Complication rates were fewer and less severe with callus distraction. The number of operations, days of hospitalization, and length of total treatment were less in patients operated on with the callus distraction method than in those who underwent the Wagner technique.
ACKNOWLEDGMENT
The authors wish to thank Susan Sharky for her assistance in preparation
of the manuscript.
REFERENCES
1. Anderson WV: Leg lengthening. J Bone Joint Surg 34B 150, 1952
2. Chauchoix J, Morel G: One stage femoral lengthening. Clin Orthop 136: 66, 1978
3. Coleman ss, Noonan TD: Andersonís method of tihial lengthening by percutaneous osteotomy and gradual distraction. J Bone Joint Surg 49A:263, 1967	
4. Coleman SS, Stevens PM: Tibial lengthening. Clin	 Orthop 136:92, 1978
5. DeBastiani G, Aldegheri R, Lodovico RB, et al: Limb lengthening by callus distraction (callotasis). J Pediatr 	 Orthop 7:129, 1987
6. Fischer DA: Skeletal stabilization with a multiplane external fixation device. Clin Orthop 180:50, 1983
7. Guidera KJ, Hess WF, Highhouse KP, et al: Extremity 	lengthening: Results and complications with the Orthofix system. J Pediatr Orthop 11:90, 1991
8. Hood RW, Riseborough EJ: Lengthening of the lower extremity by the Wagner method. J Bone Joint 	 Surg 63A:1122, 1981
9. Ilizarov GA, Deviatov AA, Trokhova VG: Surgical lengthening of the shortened lower extremities (in Russian). Vestn Khir 107:100, 1972
10. Kawamura HS, Hosano S, Takahashi T, et al: Limb lengthening by means of subcutaneous osteotomy. J Bone Joint Surg 50A:851, 1968
11. Mosley CF: A straight line graph for leg length discrepancies. Clin Orthop 136:33, 1978
12. Wagner H: Operative lengthening ofthe femur. Clin 	Orthop 136:125,1978
13. Wagner H: Surgical lengthening or shortening of femur and tibia. Technique and indications. In Hungerford DS (ed): Progress in Orthopaedic Surgery, vol 1. Leg Length Discrepancy. The Injured Knee. New York, Springer-Verlag, 1977
14. Winquist RA, Hansen ST, Pearson RE: Closed intramedullary shortening of the femur. Clin Orthop 136:54, 1978