Ashdin Publishing Journal of Case Reports in Medicine ASHDIN Vol. 2 (2013), Article ID 235710, 4 pages publishing doi:10.4303/jcrm/235710

Case Report Anterior Opening Wedge Osteotomy of the Proximal Tibia for Genu Recurvatum Caused by Partial Proximal Tibial Epiphyseal Arrest

Yo Hara,1 Yusuke Hashimoto,2 Junsei Takigami,2 Shinya Yamasaki,2 and Hiroaki Nakamura2 1Department of Orthopaedic Surgery, Shimada Hospital, 100-1 Kashiyama, Habikino, Osaka 583-0875, Japan 2Department of Orthopaedic Surgery, Osaka City University Graduate School of Medicine, 1-4-3 Asahi-machi, Abeno-ku, Osaka 545-8585, Japan Address correspondence to Yo Hara, [email protected]

Received 24 February 2013; Accepted 23 April 2013

Copyright © 2013 Yo Hara et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract For genu recurvatum deformity after tibial fracture, precise in this knee was noted about 2 years before referral to our correction osteotomy is necessary to acquire a good clinical outcome. department. No report on genu recurvatum has evaluated precise preoperative planning with image-processing software for three-dimensional (3D) The patient’s left knee appeared to have genu recurva- design and modeling. We herein report a case of osseous genu tum, and knee flexion was limited to 135 ¡ with the inability recurvatum treated by anterior opening wedge osteotomy according to to assume a kneeling position. The patient felt instability precise preoperative 3D simulation. This is a useful tool for precise during walking. The preoperative Lysholm score was 55. correction of osseous deformity. There was no length discrepancy of the lower limbs and Keywords genu recurvatum; proximal tibial epiphyseal arrest; os- general joint laxity. A lateral radiograph showed that the teotomy angle between the lines of the anatomical axis of the distal 1. Introduction part of the femoral shaft and that of the tibial shaft was Genu recurvatum has various causes, including osseous, 24 ¡ in the left leg, while it was 11 ¡ during extension at the soft tissue, and combined deformities [6]. Post-traumatic contralateral normal knee. The angle between the lines of bony deformity is the most frequent type of deformity the anatomical axis of the distal part of the femoral shaft in genu recurvatum [2]. Because precise correction of and the plane of the tibial plateau was identical to that of the osseous deformities is quite difficult, preoperative planning intact side, and the posterior tilt angle of the tibial plateau − is very important to treat genu recurvatum and obtain an was 6 ¡, which was 13 ¡ less than that of the intact side. The outcome identical to that of the contralateral knee [8]. We femorotibial angle (FTA) was 177 ¡ and 178 ¡ in the injured herein present a case in which genu recurvatum following and intact knee, respectively. Therefore, the patient was conservative therapy for proximal tibial epiphyseal injury diagnosed with purely osseous genu recurvatum (Figure 1). was treated by anterior opening wedge osteotomy according A preoperative CT scan of both lower extremities to preoperative three-dimensional (3D) planning results was performed to simulate operative planning using using the mirror image of the contralateral normal knee image-processing software (Mimics; Materialise, Leuven, obtained from a computed tomography (CT) scan with 3D Belgium) for 3D design and modeling. An injured-side reconstruction software. image was manually created from CT data overlaid on the mirror image of the contralateral intact side. In this 2. Case presentation analysis, the center of rotation of angulation was found at A 25-year-old man presented for evaluation of increasing the level of the proximal end of the tibial tuberosity 2 cm pain and genu recurvatum in his left knee. He had injured distal to the tibial plateau, and anterior open correction of his left knee while landing during gymnastics at 14 years of 13 ¡ was necessary to equalize the injured knee with the age. Radiographs at that time demonstrated an undisplaced contralateral knee. Thus, the preferable osteotomy level was proximal tibial epiphyseal injury. He was treated with a cast 2 cm distal to the tibial plateau. In addition, the simulation for 2 months followed by progressive weight-bearing and demonstrated bone resection with a thickness of 4 mm at range-of-motion exercises. He gradually became aware of the osteotomy level and an anterior opening with a 9-mm the genu recurvatum in his left knee, and progressive pain length for equalizing the contralateral knee (Figure 2). 2 Journal of Case Reports in Medicine

(a) (b)

Figure 2: Preoperative simulation of osteotomy by Mimics. (a) 3D models created from CT data. Injured side image (green areas) overlaid on the mirror image of the contralat- eral normal-side image (yellow area). The osteotomy line (black arrowheads) is at the level of the proximal end of (a) (b) the tibial tuberosity. Proximal part (purple area) is elevated for this simulation. (b) Sagittal image of the osteotomy site. Figure 1: Preoperative lateral X-ray. Genu recurvatum Yellow lines indicate the normal-side image, and purple deformity is evaluated as the angle between the lines of the lines indicate the proximal part of the injured-side image. anatomical axis of the distal part of the femoral shaft and Bone resection with a thickness of 4 mm at the level of the that of the tibial shaft (x). (a) Normal side shows an 11 ¡ proximal end of the tibial tuberosity (white arrowheads) and extension. (b) Injured side shows a 24 ¡ genu recurvatum anterior opening with a 9-mm length (white bidirectional deformity. The angle between the lines of the anatomical arrow) for equalizing the contralateral knee. axis of the distal part of the femoral shaft and the plane of the tibial plateau (y) is identical to that of the normal side, and the posterior tilt angle of tibial plateau (90 ¡ minus z) is −6 ¡, which is 13 ¡ smaller than that of the normal side.

Therefore, anterior opening wedge osteotomy 2 cm distal to the tibial plateau and plate (TomoFix, Synthes, Solothurn, Switzerland) fixation were performed. Bone resection was impossible because of hardness of the poste- rior cortex; only anterior opening elevated with an 18-mm length was possible. The gap at the osteotomy site was filled with hydroxyapatite block (NEOBONE; Toshiba Ceramics Co., Ltd., Tokyo, Japan). Correction of genu recurvatum (a) (b) (c) from 24 ¡ to 6 ¡ (5 ¡ overcorrection of the contralateral knee) Figure 3: Postoperative lateral X-ray. (a) Shortly after was obtained during the surgery. The posterior tilt angle of surgery, correction of genu recurvatum from 24 ¡ to 6 ¡ (5 ¡ the tibial plateau increased to 12 ¡ (Figure 3(a)). overcorrection of the contralateral knee) was obtained. The The patient wore a knee brace for 1 week postoper- posterior tilt angle of the tibial plateau was 12 ¡. (b) At the atively. Continuous passive motion was begun 1 week 1-year follow-up, the posterior tilt angle of the tibial plateau postoperatively. Partial and full-weight bearing were decreased to 8 ¡. (c) At the 2-year follow-up, bone union permitted 4 and 8 weeks postoperatively, respectively. was evident on X-ray after removal of the plate. There was Running was started at 4 months. The posterior tilt angle of no recurrence of genu recurvatum. the tibial plateau decreased gradually and stopped at 8 ¡ 1 year after surgery (Figures 3(b) and 3(c)). This angle was 1 ¡ larger than that of the contralateral knee. At 2 years the contralateral normal side (Figure 4), but alignment was after surgery, removal of the plate was performed, and at almost identical to normal side. the 3-year follow-up, the patient could run without pain and obtained full range of motion. The Lysholm score at the 3. Discussion final follow-up improved to 93. A 3D model image 2 years This is the first report of evaluation of genu recurvatum after surgery was 4 mm longer than the mirror image of involving an osseous deformity using precise preoperative Journal of Case Reports in Medicine 3

3D deformity [9]. Under the simulation, osseous deformity was mainly caused by anterior tibial shortening from partial proximal epiphyseal arrest, and a correction center located on the epiphysis and an anterior opening correction of 13 ¡ was necessary. We chose to perform an opening osteotomy with internal fixation according to the preoperative planning. For surgical treatment of genu recurvatum due to osseous deformity, osteotomy options include dome osteotomy, opening wedge osteotomy, and closed wedge osteotomy with internal, external, or cast fixation [1,2,3, (a) (b) 7]. Closed or dome osteotomy has the advantage of a wide contact area but has risks of neurovascular injury and leg Figure 4: Postoperative evaluation of 3D model imaging shortening. Opening wedge osteotomy has the disadvantage 2 years after surgery. (a) This showed almost the same of bone defect but has the advantage of ease of treatment. image overlaid on the mirror image of the contralateral In terms of the fixation method, external fixation can normal side. (b) The operated side (green lines) was 4 mm adjust the alignment at the osteotomy site even after longer than the mirror image of the contralateral normal side the surgery. However, it is bulky and has risks of pin (yellow lines) (white arrowheads). site infection, joint contracture, nerve palsy, and prolonged treatment [2,3]. On the other hand, plate fixation can implant planning with image-processing software for 3D design materials in the body, avoids postoperative immobilization, and modeling that simulated the osteotomy line, correction and allows the patient to begin early range of motion center, and correction volume by creating a mirror image of exercise of the knee; however, it has a risk of skin irritation the contralateral knee. and does not allow for adjustment of the alignment at the There are three types of genu recurvatum: osseous, soft osteotomy site after the surgery. The precise 3D simulation tissue, and combined. The causes of acquired genu recur- can redeem this disadvantage of plate fixation. A bone vatum include trauma (especially an epiphyseal fracture graft from the iliac crest is the most common donor site of the proximal tibia), skeletal traction via the proximal but is associated with local complications such as wound tibia, prolonged immobilization, excessive pressure on the pain, hypersensitivity, and buttock anesthesia [4]. To avoid tibial tubercle from casting or bracing, operative procedures donor site morbidity associated with harvesting the iliac involving the proximal tibial epiphysis, Osgood-Schlatter crest, the use of hydroxyapatite is reasonable. The use disease, and minor knee trauma [2,5,6,7,8]. of 3D simulation software can simulate precise operative During evaluation of patients with acquired genu recur- planning and is a powerful tool to compensate for technical vatum, it is necessary to determine whether the deformity is shortcomings of plate fixation. osseous, soft tissue, or combined [6]. The posterior tilt angle 4. Conclusion of the tibial plateau and the angle between the lines of the Preoperative simulation with image-processing software for anatomical axis of the distal part of the femoral shaft and three-dimensional design and modeling is a useful tool for the plane of the tibial plateau on lateral X-ray are important precise correction of osseous deformity. for diagnosis of genu recurvatum. The posterior tilt angle of the tibial plateau in soft tissue genu recurvatum is normal, References but the angle between the femoral shaft and tibial plateau [1] A.L.Brett,Operative correction of genu recurvatum, J Bone Joint is irregular. On the other hand, in osseous genu recurvatum, Surg, 17 (1935), 984Ð989. the posterior tilt angle is irregular, but the angle between [2] L. C. Chen, Y. S. Chan, and C. J. Wang, Opening-wedge the femoral shaft and tibial plateau is normal. Some arti- osteotomy, allografting with dual buttress plate fixation for severe genu recurvatum caused by partial growth arrest of the proximal cles reported anterior opening wedge high tibial osteotomy tibial physis: a case report, J Orthop Trauma, 18 (2004), 384Ð387. (HTO) for treatment of genu recurvatum caused by partial [3] I. H. Choi, C. Y. Chung, T. J. Cho, and S. S. Park, Correction of proximal tibial epiphyseal arrest. However, these cases were genu recurvatum by the Ilizarov method, J Bone Joint Surg Br, 81 only evaluated by X-ray photography [2,5,8]. (1999), 769Ð774. [4] J. Cockin, Autologous bone grafting—complications at the donor Lateral X-ray is insufficient for preoperative planning site, J Bone Joint Surg Br, 53 (1971), 153. to acquire precise bony correction. In this case, correction [5] J. L. 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[7] E. Segev, D. Hendel, and S. Wientroub, Genu recurvatum in an adolescent girl: hypothetical etiology and treatment considera- tions. A case report, J Pediatr Orthop B, 11 (2002), 260Ð264. [8]R.Takai,A.D.Grant,D.Atar,andW.B.Lehman,Minor knee trauma as a possible cause of asymmetrical proximal tibial physis closure. A case report, Clin Orthop Relat Res, 307 (1994), 142Ð 145. [9] Y. Z. Zhang, S. Lu, B. Chen, J. M. Zhao, R. Liu, and G. X. Pei, Application of computer-aided design osteotomy template for treatment of cubitus varus deformity in teenagers: a pilot study,J Shoulder Elbow Surg, 20 (2011), 51Ð56.