|Year : 2022 | Volume
| Issue : 1 | Page : 86-89
Hybrid external fixator for correction of genu valgum in an adult
Tanmoy Mohanty1, Madhuchhanda Pattnaik2, Gopal Chandra Sethy1, Rabi Narayan Jee1
1 Department of Orthopaedics, SCB Medical College, Cuttack, Odisha, India
2 Department of Physiology, SCB Medical College, Cuttack, Odisha, India
|Date of Submission||27-Jun-2021|
|Date of Acceptance||08-Dec-2021|
|Date of Web Publication||15-Jun-2022|
Dr. Madhuchhanda Pattnaik
Burdwan Compound, College Square P.O., Cuttack - 753 003, Odisha
Source of Support: None, Conflict of Interest: None
Sometimes genu valgum in an adult poses a challenge to orthopedic surgeons because the deformity is very gross if it developed due to injury or infection in early childhood. If the femoral condyle is found to be hypoplastic, then the corrective osteotomy site is very close to the joint. It may be difficult to manage with a conventional fixator and a hybrid fixator may become a necessity. A limb reconstruction system (LRS) is less cumbersome than ring fixators when fixed to the thigh. A hybrid fixator fabricated using a twin-ring Ilizarov system attached to an LRS was found to be very useful during the management of corrective osteotomy of genu valgum in an adult. A special clamp was designed to fix the Ilizarov portion to the end of the rail system of LRS. Here, the use of such a hybrid fixator to correct the deformity of the right knee in a 27-year-old person has been described in detail.
Keywords: Correction, external fixator, genu valgum, hybrid
|How to cite this article:|
Mohanty T, Pattnaik M, Sethy GC, Jee RN. Hybrid external fixator for correction of genu valgum in an adult. J Orthop Traumatol Rehabil 2022;14:86-9
|How to cite this URL:|
Mohanty T, Pattnaik M, Sethy GC, Jee RN. Hybrid external fixator for correction of genu valgum in an adult. J Orthop Traumatol Rehabil [serial online] 2022 [cited 2022 Jun 27];14:86-9. Available from: https://www.jotr.in/text.asp?2022/14/1/86/347370
| Introduction|| |
Genu valgum in children is a very common deformity encountered by orthopedic surgeons. Genu valgum is fairly common, affecting more than 20% of 3-year-olds, and in the majority, the condition naturally corrects by itself. However, genu valgum may continue into adolescence. Rickets is one of the conditions causing genu valgum. Unilateral genu valgum is uncommon and sometimes is caused by infection of the knee at a growing age. Recovery after corrective surgery of genu valgum in adults takes a long time because the bone healing is not as fast as in growing children. It requires meticulous planning to avoid complications. In this article, a detailed description is given for the correction of gross genu valgum in an adult by the use of a hybrid fixator having a specially designed clamp.
| Case Report|| |
A 27-year-old male attended our hospital with gross deformity in his right knee following a pyogenic infection when he was 10 years old. He had no other complaint except the knee deformity for which he used to walk with the aid of a stick. On clinical examination, it was found out that he had fixed flexion deformity (FFD) of 15° of the right knee with 35° of valgus in comparison to the unaffected left knee. Fractional measurement of the right lower limbs revealed 1 cm shortening on the femoral side only. No instability was detected and the flexion range was full. On detailed examination, he was found to have restriction of external rotation of the left hip in the terminal range. X-ray of the right knee showed valgus in anteroposterior view with the hypoplastic lateral condyle of the femur [Figure 1]. Radiograph of the pelvis with both hips revealed coxa vara of the left hip, possibly due to septic arthritis in childhood. The patient wanted correction of the deformity of the right knee which may allow him to avoid using the stick during ambulation.
|Figure 1: Preoperative radiograph showing gross genu valgum with the hypoplastic lateral femoral condyle|
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While planning for the corrective surgery, a thorough literature review revealed various authors using distal femoral varus osteotomy with blade plate fixation for correction of the valgus knee in adults. Tetsworth and Paley in a study of 28 limbs in 23 patients to correct complex lower limb deformities, inferred that gradual mechanical distraction by Ilizarov fixator gave accurate corrections.
The primary goal of external fixation is to maintain the length, alignment, and rotation of the bone fragments. Physiological healing of fractures depends on the mode of fixation and level of stability. External fixators are of several different varieties. These include uniplanar, multiplanar, unilateral, bilateral, and circular fixators. Uniplanar fixators can be done fast and easy to apply but usually are not sturdy as compared to multiplanar ones. Circular fixators such as Ilizarov became more popular for deformity correction or bone transportations because they allowed weight-bearing during the procedures which usually takes a long time. During the treatment of fractures near a joint by Ilizarov fixators, stability of a short metaphysical fragment usually causes a problem, and sometimes, it becomes necessary to bridge the adjacent joint to ensure stable fixation. Hybrid fixators are preferred while dealing with fractures close to the joint. It was planned to use a hybrid external fixator made up of limb reconstruction system (LRS) (dynamic axial fixator with rail system) and partly Ilizarov. A specially designed clamp allowed fixation of the proximal-most ring to the end of LRS.
The patient was explained in detail about the pros and cons of corrective surgery using an external fixator and was prepared accordingly. The patient was exposed to the surgery under spinal anesthesia. The LRS portion of the fixator was fixed to the femoral shaft with two tapered Schanz pins. An Ilizarov of the ring was secured to the end of the LRS rail with the specially designed clamp [Figure 2]a, and a Schanz pin was fixed to the femur just above the contemplated cortiocotomy site for better stability [Figure 2]b. Distal to that ring, another ring was placed just above the knee joint transfixing the condylar region with wires. Two Ilizarov joints were placed between these two rings at the desired center of rotation and angulation (CORA), and corticotomy was done at the supracondylar region. The joints were loosened to confirm the completion of corticotomy, and the completed assembly was finally checked with an image intensifier [Figure 2]c and [Figure 2]d after the joint was spanned with two rings attached to the proximal tibia [Figure 3]a. Postoperative recovery was uneventful. Gradual distraction on the lateral side was started from the 8th postoperative day with an increment of 1.5 mm per day till the desired correction of valgus was achieved, which took about 22 days. The limb was exposed to X-ray thrice only in the meantime to confirm the position [Figure 3]b and [Figure 3]c. The knee had been fixed at 10° of flexion which was not corrected at the time of surgery, and also it was decided not to alter it using the fixator. The status of the common peroneal nerve was checked clinically and it was never affected.
|Figure 2: Femoral construct showing the special clamp (a). Schanz pin fixed just above the corticotomy site for better stability (b). Completion of corticotomy confirmed by loosening the joints and checked by image intensifier (c and d)|
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|Figure 3: View of hybrid fixator construct after the fixation of the tibia (a). Just postoperative radiograph showing the position of corticotomy (b). Radiograph showing correction at corticotomy site (c) radiograph of the femur at 7-month follow-up (d)|
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| Results|| |
Some lateral translation was observed at the corticotomy site [Figure 3]d which helped achieve limb alignment. Threaded rods were attached between the two Ilizarov rings, and the patient was allowed to weight-bear partially with the aid of a walker. After another 4 weeks, i.e., 7 weeks postsurgery, the joint spanning part was removed from the tibia and the knee joint was mobilized with supervised physiotherapy. Although the fixation of the corticotomy site looked stable, it was preferred to keep the patient nonweight-bearing and mobilized the knee for another 3 weeks. Finally, at the end of 10 weeks, he was ambulating with a walker without valgus knee but with fixed flexion of the knee about 10°. Finally, at 17th week when radiographically sufficient consolidation was observed at the corticotomy site, the fixator was removed. No problems were encountered pertaining to the fixator except superficial infection at the proximal-most Schanz pin on the thigh and one olive wire at the medical part of the condyle. It was resolved with meticulous dressing and pin care.
The patient was able to bear full weight bearing after removal of the fixator, although he preferred to use a walking stick for about 2 weeks. At 7-month follow-up, the patient could comfortably walk and run, although he had FFD of the knee about 10° [Figure 4]a and [Figure 4]b. Scanogram showed very good alignment of the affected limb in comparison to the sound limb [Figure 5]a and [Figure 5]b, and he had the only restriction of the last 10° of terminal flexion. He had no problem with patellar tracking.
|Figure 4: Clinical photographs showing correction and fixed flexion deformity of the right knee (a and b)|
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|Figure 5: Scanograms before and after correction of genu valgum (a and b)|
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| Discussion|| |
Mild genu valgum does not normally cause any disability except the knock-knee. Many individuals who have genu valgum in adulthood prefer not to get a corrective surgery done, However, sometimes, the deformity becomes too large if the growth of lateral condyle becomes too much affected. This is mostly due to an injury or infection in early childhood, with a long time to go for skeletal maturity. The angulation at the knee in this case was around 35°, which gave a lot of difficulty to the patient while bearing weight. Hence, he preferred to use a stick to stand upright and thus developed FFD in the knee.
The correction of genu valgum by opening wedge osteotomy is not very difficult in growing age. However, in adults, the gap invariably needs to be filled up by bone graft. Furthermore, on table correction can lead to stretching of the common peroneal nerve.
Hence, it was preferred to take advantage of gradual correction and distraction osteogenesis using the method of Ilizarov. Femoral constructs in Ilizarov are cumbersome for using rings and arches at the upper thigh. It was planned to use a unilateral rail system fixator LRS for anchoring the femoral portion of the fixator, and two Ilizarov rings were placed above and below the contemplated corticotomy site at the supracondylar region of the femur. A special clamp was designed to fix the ring portion to the end of the rail system. The twin-ring construct in Ilizarov has been considered to be a sturdy fixation as studied by Grivas and Magnissalis.
As the distal ring over the condylar fragment was very close to the knee joint, it was decided to span the joint and attach two rings to the upper tibia. This allowed the patient partial weight-bearing early. This tibial construct was removed later to free the knee joint to gain range of movement. As the corticotomy was little proximal to the CORA, translation was encountered at the corticotomy site, which later proved to be beneficial to gain proper limb alignment, as seen in the final scanogram. No intervention was done for the coxa vara in the contralateral hip because the patient had no complaints. At 7 months of follow-up, he had 10° of FFD in the knee, which may correct later by physiotherapy. The patient was comfortably walking around and could run also without limping.
| Conclusion|| |
Gross genu valgum in adults acquired in childhood poses a challenge to orthopedic surgeons. Meticulous planning is necessary if deformity correction is contemplated by the use of the method of Ilizarov. This specially designed hybrid fixator proved to be very useful.
Ethical standard statement and consent
All procedures followed were in accordance with the ethical standards of the responsible committee on human experimentation (institutional and national) and with the Helsinki Declaration of 1975, as revised in 2008 (5). Informed consent was obtained from the patient for being included in the study.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given his consent for his images and other clinical information to be reported in the journal. The patient understands that his name and initials will not be published and due efforts will be made to conceal his identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
| References|| |
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Tetsworth KD, Paley D. Accuracy of correction of complex lower-extremity deformities by the Ilizarov method. Clin Orthop Relat Res 1994;301:102-10.
Hadeed A, Werntz RL, Varacallo M. External fixation principles and overview. In: StatPearls. Treasure Island (FL): StatPearls Publishing; 2021.
Dar RA, Latoo I, Ashraf A, Wani MM, Bhat MR, Bhat MY. New hybrid external fixator for complex tibial platau fractures: A minimally invasive technique. Tech Orthop 2015;30:111-3.
Grivas TB, Magnissalis EA. The use of twin-ring Ilizarov external fixator constructs: Application and biomechanical proof-of principle with possible clinical indications. J Orthop Surg Res 2011;6:41.
[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]