Ashdin PublishingJournal of Case Reports in MedicineVol. 2 (2013), Article ID 235710, 4 pagesdoi:10.4303/jcrm/235710

ASHDINpublishing

Case Report

Anterior Opening Wedge Osteotomy of the Proximal Tibia for GenuRecurvatum 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, Japan2Department 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, yhara@heartful-health.or.jp

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, whichpermits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract For genu recurvatum deformity after tibial fracture, precisecorrection osteotomy is necessary to acquire a good clinical outcome.No report on genu recurvatum has evaluated precise preoperativeplanning with image-processing software for three-dimensional (3D)design and modeling. We herein report a case of osseous genurecurvatum treated by anterior opening wedge osteotomy according toprecise preoperative 3D simulation. This is a useful tool for precisecorrection of osseous deformity.

Keywords genu recurvatum; proximal tibial epiphyseal arrest; os-teotomy

1. IntroductionGenu recurvatum has various causes, including osseous,soft tissue, and combined deformities [6]. Post-traumaticbony deformity is the most frequent type of deformityin genu recurvatum [2]. Because precise correction ofosseous deformities is quite difficult, preoperative planningis very important to treat genu recurvatum and obtain anoutcome identical to that of the contralateral knee [8]. Weherein present a case in which genu recurvatum followingconservative therapy for proximal tibial epiphyseal injurywas treated by anterior opening wedge osteotomy accordingto preoperative three-dimensional (3D) planning resultsusing the mirror image of the contralateral normal kneeobtained from a computed tomography (CT) scan with 3Dreconstruction software.

2. Case presentationA 25-year-old man presented for evaluation of increasingpain and genu recurvatum in his left knee. He had injuredhis left knee while landing during gymnastics at 14 years ofage. Radiographs at that time demonstrated an undisplacedproximal tibial epiphyseal injury. He was treated with a castfor 2 months followed by progressive weight-bearing andrange-of-motion exercises. He gradually became aware ofthe genu recurvatum in his left knee, and progressive pain

in this knee was noted about 2 years before referral to ourdepartment.

The patient’s left knee appeared to have genu recurva-tum, and knee flexion was limited to 135 ° with the inabilityto assume a kneeling position. The patient felt instabilityduring walking. The preoperative Lysholm score was 55.There was no length discrepancy of the lower limbs andgeneral joint laxity. A lateral radiograph showed that theangle between the lines of the anatomical axis of the distalpart of the femoral shaft and that of the tibial shaft was24 ° in the left leg, while it was 11 ° during extension at thecontralateral normal knee. The angle between the lines ofthe anatomical axis of the distal part of the femoral shaftand the plane of the tibial plateau was identical to that of theintact side, and the posterior tilt angle of the tibial plateauwas −6 °, which was 13 ° less than that of the intact side. Thefemorotibial angle (FTA) was 177 ° and 178 ° in the injuredand intact knee, respectively. Therefore, the patient wasdiagnosed with purely osseous genu recurvatum (Figure 1).

A preoperative CT scan of both lower extremitieswas performed to simulate operative planning usingimage-processing software (Mimics; Materialise, Leuven,Belgium) for 3D design and modeling. An injured-sideimage was manually created from CT data overlaid onthe mirror image of the contralateral intact side. In thisanalysis, the center of rotation of angulation was found atthe level of the proximal end of the tibial tuberosity 2 cmdistal to the tibial plateau, and anterior open correction of13 ° was necessary to equalize the injured knee with thecontralateral knee. Thus, the preferable osteotomy level was2 cm distal to the tibial plateau. In addition, the simulationdemonstrated bone resection with a thickness of 4 mm atthe osteotomy level and an anterior opening with a 9-mmlength for equalizing the contralateral knee (Figure 2).

2 Journal of Case Reports in Medicine

(a) (b)

Figure 1: Preoperative lateral X-ray. Genu recurvatumdeformity is evaluated as the angle between the lines of theanatomical axis of the distal part of the femoral shaft andthat of the tibial shaft (x). (a) Normal side shows an 11 °extension. (b) Injured side shows a 24 ° genu recurvatumdeformity. The angle between the lines of the anatomicalaxis of the distal part of the femoral shaft and the plane ofthe 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 cmdistal to the tibial plateau and plate (TomoFix, Synthes,Solothurn, Switzerland) fixation were performed. Boneresection was impossible because of hardness of the poste-rior cortex; only anterior opening elevated with an 18-mmlength was possible. The gap at the osteotomy site was filledwith hydroxyapatite block (NEOBONE; Toshiba CeramicsCo., Ltd., Tokyo, Japan). Correction of genu recurvatumfrom 24 ° to 6 ° (5 ° overcorrection of the contralateral knee)was obtained during the surgery. The posterior tilt angle ofthe tibial plateau increased to 12 ° (Figure 3(a)).

The patient wore a knee brace for 1 week postoper-atively. Continuous passive motion was begun 1 weekpostoperatively. Partial and full-weight bearing werepermitted 4 and 8 weeks postoperatively, respectively.Running was started at 4 months. The posterior tilt angle ofthe tibial plateau decreased gradually and stopped at 8 ° 1year after surgery (Figures 3(b) and 3(c)). This angle was1 ° larger than that of the contralateral knee. At 2 yearsafter surgery, removal of the plate was performed, and atthe 3-year follow-up, the patient could run without pain andobtained full range of motion. The Lysholm score at thefinal follow-up improved to 93. A 3D model image 2 yearsafter surgery was 4 mm longer than the mirror image of

(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 ofthe tibial tuberosity. Proximal part (purple area) is elevatedfor this simulation. (b) Sagittal image of the osteotomy site.Yellow lines indicate the normal-side image, and purplelines indicate the proximal part of the injured-side image.Bone resection with a thickness of 4 mm at the level of theproximal end of the tibial tuberosity (white arrowheads) andanterior opening with a 9-mm length (white bidirectionalarrow) for equalizing the contralateral knee.

(a) (b) (c)

Figure 3: Postoperative lateral X-ray. (a) Shortly aftersurgery, correction of genu recurvatum from 24 ° to 6 ° (5 °overcorrection of the contralateral knee) was obtained. Theposterior tilt angle of the tibial plateau was 12 °. (b) At the1-year follow-up, the posterior tilt angle of the tibial plateaudecreased to 8 °. (c) At the 2-year follow-up, bone unionwas evident on X-ray after removal of the plate. There wasno recurrence of genu recurvatum.

the contralateral normal side (Figure 4), but alignment wasalmost identical to normal side.

3. Discussion

This is the first report of evaluation of genu recurvatuminvolving an osseous deformity using precise preoperative

Journal of Case Reports in Medicine 3

(a) (b)

Figure 4: Postoperative evaluation of 3D model imaging2 years after surgery. (a) This showed almost the sameimage overlaid on the mirror image of the contralateralnormal side. (b) The operated side (green lines) was 4 mmlonger than the mirror image of the contralateral normal side(yellow lines) (white arrowheads).

planning with image-processing software for 3D designand modeling that simulated the osteotomy line, correctioncenter, and correction volume by creating a mirror image ofthe contralateral knee.

There are three types of genu recurvatum: osseous, softtissue, and combined. The causes of acquired genu recur-vatum include trauma (especially an epiphyseal fractureof the proximal tibia), skeletal traction via the proximaltibia, prolonged immobilization, excessive pressure on thetibial tubercle from casting or bracing, operative proceduresinvolving the proximal tibial epiphysis, Osgood-Schlatterdisease, and minor knee trauma [2,5,6,7,8].

During evaluation of patients with acquired genu recur-vatum, it is necessary to determine whether the deformity isosseous, soft tissue, or combined [6]. The posterior tilt angleof the tibial plateau and the angle between the lines of theanatomical axis of the distal part of the femoral shaft andthe plane of the tibial plateau on lateral X-ray are importantfor diagnosis of genu recurvatum. The posterior tilt angle ofthe tibial plateau in soft tissue genu recurvatum is normal,but the angle between the femoral shaft and tibial plateauis irregular. On the other hand, in osseous genu recurvatum,the posterior tilt angle is irregular, but the angle betweenthe femoral shaft and tibial plateau is normal. Some arti-cles reported anterior opening wedge high tibial osteotomy(HTO) for treatment of genu recurvatum caused by partialproximal tibial epiphyseal arrest. However, these cases wereonly evaluated by X-ray photography [2,5,8].

Lateral X-ray is insufficient for preoperative planningto acquire precise bony correction. In this case, correctionosteotomy was performed according to the preoperativeprecise 3D simulation by Mimics. The computer-assistedtemplate can indicate the optimum pattern and plane ofcorrective osteotomy by calculating the axis and amount of

3D deformity [9]. Under the simulation, osseous deformitywas mainly caused by anterior tibial shortening from partialproximal epiphyseal arrest, and a correction center locatedon the epiphysis and an anterior opening correction of 13 °was necessary. We chose to perform an opening osteotomywith internal fixation according to the preoperative planning.

For surgical treatment of genu recurvatum due toosseous deformity, osteotomy options include domeosteotomy, opening wedge osteotomy, and closed wedgeosteotomy with internal, external, or cast fixation [1,2,3,7]. Closed or dome osteotomy has the advantage of a widecontact area but has risks of neurovascular injury and legshortening. Opening wedge osteotomy has the disadvantageof bone defect but has the advantage of ease of treatment.

In terms of the fixation method, external fixation canadjust the alignment at the osteotomy site even afterthe surgery. However, it is bulky and has risks of pinsite infection, joint contracture, nerve palsy, and prolongedtreatment [2,3]. On the other hand, plate fixation can implantmaterials in the body, avoids postoperative immobilization,and allows the patient to begin early range of motionexercise of the knee; however, it has a risk of skin irritationand does not allow for adjustment of the alignment at theosteotomy site after the surgery. The precise 3D simulationcan redeem this disadvantage of plate fixation. A bonegraft from the iliac crest is the most common donor sitebut is associated with local complications such as woundpain, hypersensitivity, and buttock anesthesia [4]. To avoiddonor site morbidity associated with harvesting the iliaccrest, the use of hydroxyapatite is reasonable. The useof 3D simulation software can simulate precise operativeplanning and is a powerful tool to compensate for technicalshortcomings of plate fixation.

4. Conclusion

Preoperative simulation with image-processing software forthree-dimensional design and modeling is a useful tool forprecise correction of osseous deformity.

References

[1] A. L. Brett, Operative correction of genu recurvatum, J Bone JointSurg, 17 (1935), 984–989.

[2] L. C. Chen, Y. S. Chan, and C. J. Wang, Opening-wedgeosteotomy, allografting with dual buttress plate fixation for severegenu recurvatum caused by partial growth arrest of the proximaltibial physis: a case report, J Orthop Trauma, 18 (2004), 384–387.

[3] I. H. Choi, C. Y. Chung, T. J. Cho, and S. S. Park, Correction ofgenu recurvatum by the Ilizarov method, J Bone Joint Surg Br, 81(1999), 769–774.

[4] J. Cockin, Autologous bone grafting—complications at the donorsite, J Bone Joint Surg Br, 53 (1971), 153.

[5] J. L. Knight, Genu recurvatum deformity secondary to partialproximal tibial epiphyseal arrest: case report, Am J Knee Surg,11 (1998), 111–115.

[6] A. Moroni, V. Pezzuto, M. Pompili, and G. Zinghi, Proximalosteotomy of the tibia for the treatment of genu recurvatum inadults, J Bone Joint Surg Am, 74 (1992), 577–586.

4 Journal of Case Reports in Medicine

[7] E. Segev, D. Hendel, and S. Wientroub, Genu recurvatum in anadolescent girl: hypothetical etiology and treatment considera-tions. A case report, J Pediatr Orthop B, 11 (2002), 260–264.

[8] R. Takai, A. D. Grant, D. Atar, and W. B. Lehman, Minor kneetrauma as a possible cause of asymmetrical proximal tibial physisclosure. A case report, Clin Orthop Relat Res, 307 (1994), 142–145.

[9] Y. Z. Zhang, S. Lu, B. Chen, J. M. Zhao, R. Liu, and G. X.Pei, Application of computer-aided design osteotomy template fortreatment of cubitus varus deformity in teenagers: a pilot study, JShoulder Elbow Surg, 20 (2011), 51–56.