Minimal invasive epiphysiodesis using a modified “Canale”-technique for correction of angular deformities and limb leg length discrepancies

Abstract

Purpose

Leg length discrepancy and angular deformities can, in contrast to adults; easily be corrected with epiphysiodesis during growth. Goal of this study was to evaluate our results of a modified Canale technique for definitive epiphysiodesis treating leg length discrepancy and also angular deformities.

Methods

Between 2000 and 2007, 22 patients (11 boys and 11 girls) were subjected to definitive epiphysiodesis. In total 73 hemiepiphysiodesis were performed (26 proximal tibial, 47 distal femoral).

Results

All patients could be followed to the end of growth. Mean follow-up was 32.2 month (range 13–76 months). In 20 patients the epiphysiodesis was planed to correct axis and leg length discrepancy. In two patients’ contralateral epiphysiodesis was performed to avoid further leg length discrepancy because of closed physis of the shorter affected side. A staged procedure was necessary in nine patients to achieve the best possible correction. No complications were seen such as wound healing, knee-joint contractures after epiphysiodesis of the distal femur and proximal tibia. In two patients three rehemiepiphysiodesis because of not fully closure of the physis had to be done.

Conclusion

Definitive epiphysiodesis using this modified Canale technique is a safe, minimal invasive method to correct leg length discrepancy and angular deformities if preoperative planning is performed properly.

Introduction

Epiphysiodesis is an accepted method for correcting leg length discrepancy and is increasingly being used for angular deformities in children and adolescents. Phemister in 1933 [1] is credited with first description of the fusion of the growth plate. It included resection of a rectangular portion of bone containing metaphysis, epiphysis, and its reinsertion with ends reversed resulting in a bony bridge. Its disadvantages included irreversibility, considerable pain, prolonged postoperative recovery, extensive scarring, secondary angular deformities and exostosis.

Blount and Clarke in 1949 [2] introduced a method with application of staples to the growth plate to slow it down, keeping it potentially reversible. Outcome was unpredictable, since after staple removal only the preserved perichondral ring and epiphyseal vessels would allow adequate growth resumption.

Various techniques have been introduced using power drills and dental burs to destroy the physis percutaneously. These techniques made epiphysiodesis approachable through a minimal invasive procedure [3–8]. These procedures tend to permanently fuse the growth plate.

We have used a percutaneous total or partial epiphysiodesis through a minimal invasive approach using a modified Canale-technique, which was primarily published in 1986 [9]. This technique is easy to perform and includes resection of the physeal bar on outpatient bases, allowing early rehabilitation. It was primarily utilized for leg length difference. We not only corrected leg length, but also angular deformities of the lower extremity. In contrast to Canale, we sometimes even evaluated staged procedure for acquiring the desired correction. In this report, we present our results with this technique in a retrospective study.

Materials and methods

Between 2000 and 2007, 22 patients (11 boys and 11 girls) underwent definitive epiphysiodesis for correction of leg length discrepancy and angular deformity (Table 1). In total 73 hemiepiphysiodesis were performed (26 proximal tibial, 47 distal femoral).

Table 1.

Diagnosis and the procedures for epiphysiodesis

Patient	Diagnosis	Leg length discrepancy	Axis deviation	Combined	Staged procedure	Level of correction1
1	Idiopathic	Yes				a, b, c, d
2	Idiopathic	Yes	Yes	Yes	Yes	c, d
3	Idiopathic		Yes			a, a
4	Idiopathic	Yes				a, b, c, d
5	Idiopathic	Yes				a, b
6	Idiopathic	Yes			Yes	a, b, c, d
7	Idiopathic		Yes		Yes	a, a, b, b
8	Idiopathic	Yes			Yes	a, a, b, b
9	Posttraumatic	Yes				a, b
10	Posttraumatic	Yes				a, b, c, d
11	Posttraumatic	Yes				a, b
12	Posttraumatic	Yes				a, b
13	Posttraumatic	Yes				a, b, c, d
14	Lipomeningomyelocele	Yes				c, d
15	Congenital tibia pseudarthrosis	Yes			Yes	a, b, c, d
16	Epiphysiolysis capitis femoris	Yes			Yes	a, b, c, d
17	Cyst proximal femur	Yes				a, b
18	Clubfoot	Yes	Yes	Yes	Yes	a, a, b, b, c, d
19	Longitudinal fibular defect	Yes				a, b, c, d
20	Angiodysplasia	Yes				a, b
21	Hypophosphataemic rickets		Yes		Yes	a, a, b, d
22	Morbus Blount	Yes	Yes	Yes	Yes	a, b, c, d, d

¹Level of correction: a distal femur medial, b distal femur lateral, c proximal tibia medial, d proximal tibia lateral

The etiologies for leg length discrepancies and angular deformities included the following: eight idiopathic, five following trauma, one cyst in the proximal femur, congenital pseudarthrosis of the tibia in one patient, one epiphysiolysis capitis femoris, one clubfoot, one angiodysplasia, one x-linked hypophosphataemic rickets, one Morbus Blount and each a lipomeningomyelocele and longitudinal fibular defect in one case.

Clinical evaluation included assessment of leg length differences, angular deformities as well as height. Radiological evaluation included analyses of the axes and leg length discrepancy (Orthoradiogram), chronological age and skeletal age according to the method of Greulich and Pyle [10]. The radiological evaluation was standardized by using long standing X-rays with the patellae directed forward.

Skeletal age of the hand and wrist was analyzed according to the method described by Greulich and Pyle [10]. According to the tables of Bailey and Pinneau [11], expected adult height was calculated. Remaining growth of the distal femur and proximal tibia is based on the tables published by Anderson and Green [12]. According to these data, 37% of the height of the leg is localized in the distal femur and 28% to the proximal tibia [13]. Chronological age at the time of diagnosis was 13.3 (range 7.3–16.9 years), skeletal age 13 (range 9–15 years) and the % of expected adult height was 92.6% (range 79–97.4%).

Surgical technique

In his original publication, Canale [9, 14] describes a percutaneous epiphysiodesis using a Kirschner–Wire and performing the epiphysiodesis with a cannulated reamer and a high-speed pneumatic drill.

Under general or epidural anesthesia a skin incision is performed directly over the epiphysis medially and/or laterally. Under image intensifier the physis is visualized and directly approached with a 3.5 cm drill. The drill is exchanged to a 4.5 mm. This 4.5 mm drill is directed ‘star-wise’ to reach the full physis. Then the physis is destroyed by using an “olive drill” working as a reamer and an additional angulated curette. A case for valgus correction with a staged procedure because of the different valgus deformity is shown in Fig. 1a–d.

Fig. 1.

a Preoperative radiograph in a patient with a bilateral valgus deformity (Patient Nr 3). b Intraoperative documentation of the medial distal femoral hemiepiphysiodesis with the olive drill and the curettage. c Orthoradiography before performing the second leg. d Orthoradiography at latest follow-up with fully correction of the valgus deformity

Postoperative regimen includes full weight bearing immediately after surgery and sport restriction for 2 weeks. Patients were followed up clinically and radiographically in short stages to allow assessment of correct fusion of the physis and consecutive changes on the extremities. This strategy allows a staged procedure with epiphysiodesis if desired correction is not achieved after index operation.

Results

The site and timing of epiphysiodesis were dependent upon the calculations made to achieve full correction at the time adult height is reached. Re-interventions using the same technique were necessary in a few (n = 2) patients if within 3 months the intended closure of the physis (complete or incomplete) was not visible on X-rays.

The goals of correction of angular deviations and leg length discrepancy have been achieved in all patients according to the calculated remaining growth potentials.

All patients could be followed to the end of growth. Mean follow-up was 32.2 month (range 13–76 months). Leg length discrepancy and angular correction are presented in Table 2. In 20 patients the epiphysiodesis was planned to correct axis and leg length discrepancy. In two patients’ contra lateral epiphysiodesis was performed to avoid further leg length discrepancy because of closed physis of the shorter affected side (tibial pseudarthrosis, lipomeningomyelocele). The staged procedure was necessary in nine patients to achieve the best possible correction.

Table 2.

In Patient 14 and 15 epiphysiodesis was performed to avoid further leg length discrepancy

Patient	Leg length (mm)	Leg length follow-up	Axis (contralateral side) + Varus − Valgus	Axis follow-up	Rehemiepiphysiodesis	Chronological age (years)	Skeletal age (years)a	% Of heightb	Follow-up (all to the end of growth) month
1	1.5	0				13 5/12	13 ½	97.4	21
2	2.5	1	5	−1	Yes	12 7/12	13	87.3	26
3			−8 (−4)	0 (0)		13 ¾	13 ½	90.2	40
4	2	0				13 1/6	13 ½	97.4	30
5	2.5	1				14	14	92.7	13
6	3	0				11	11	90.6	76
7			−4 (−5)	0 (0)		16 11/12	13	96.4	22
8	1.9	0				13 5/12	14	92.7	25
9	3	−0.3				13 11/12	12	93.2	49
10	4	2.5				15 5/12	14	92.7	21
11	2	0.5				14 ¾	14	92.7	14
12	2	1.5				14 ¾	15	96.8	10
13	1.5	1				15 1/3	15	96.8	27
14	3	2.5				11 11/12	12	92.2	33
15	6	5				14 ¾	14	92.7	28
16	3	0.9				11 11/12	12	92.2	45
17	2	0.5				13 ¾	13 ½	90.2	23
18	2.5	2	−8 (−6)	0 (3)		12 5/6	12	92.2	58
19	3	1.5				13 1/6	13	95.8	21
20	1.5	0				13	13	95.8	20
21			19 (5)	15 (5)		11 1/12	11	90.6	39
22	1	0.5	17	1	Yes (TWICE)	7 1/3	9	79	58

^aAccording Greulich and Pyle [10]

^bAccording Bailey and Pinneau [11]

In order to avoid overcorrection of angular deformities completion of the epiphysiodesis was performed in (n = 5) patients when the axis was neutralized.

Also when the leg length was equalized in cases of leg length discrepancy the contralateral physis was closed in (n = 3) patients.

This allowed correcting leg length discrepancy and angular deviation in all those patients with sufficient growth remaining. Only in one patient this was not achieved—as expected from the preoperative calculations.

No complications were seen such as wound healing, knee-joint contractures after epiphysiodesis of the distal femur and proximal tibia. In two patients three rehemiepiphysiodesis because of not fully closure of the physis had to be done.

Discussion

After Phemister in 1933 [1], various publications have outlined the feasibility and correction potential of the percutaneous epiphysiodesis with or without use of hardware for temporary fixation [3, 4, 6, 7, 15–17]. Pitfalls include errors in the prediction of growth and planning of the surgery.

Epiphysiodesis using the modified Canale technique can be performed minimally invasive and on an outpatient basis. The treatment was performed in one stage.

In our series of patients a slightly modified Canale-technique used has allowed to reliably achieve the attempted corrections. Correction of an angular deformity is more demanding than correction of a leg length discrepancy. For this reason precise preoperative planning is very important. All patients were treated on outpatient basis. None of them required rehabilitation facilities such as physiotherapy. Re-epiphysiodesis was performed when closure was not evident radiographically within 3 months using the same technique.

We want to stress that epiphysiodeses and hemi-epiphysiodeses ought not to be considered as a one simple single-step surgery but as a staged procedure: with careful planning epiphysiodesis should be performed at a time leaving sufficient remaining growth. When angular deformities or leg length discrepancy is corrected after epiphysiodesis closure of the physis has to be completed by either destroying the rest of the physis or by contralateral epiphysiodesis. With careful planning this can be reached with very little loss of final height. Correct axial alignment and leg length equality are more important physiologically than a minimally diminished final height.

Conclusion

Epiphysiodesis using this technique is very simple if a few important aspects are followed: determining of remaining growth is the crucial point which is easily done by using appropriate growth charts and standards. However even more important is to carefully monitor the growth following epiphysiodesis and to react appropriately by closing the physis after hemi-epiphysiodesis when angular correction is achieved or to close the contralateral physis when leg length is equalized.