The Knee 11(2004) 319–321

0968-0160/04/$ - see front matter� 2003 Elsevier B.V. All rights reserved.doi:10.1016/j.knee.2003.09.007

Inclination of the joint line in supracondylar osteotomy of the femur forvalgus deformity

Ricardo Navarro, Mario Carneiro*

Department of Orthopedics and Traumatology, Universidade Federal de Sao Paulo, Escola Paulista de Medicina, Rua Macau 300, Sao Paulo,˜ ˜SP, 04032-020, Brazil

Received 14 June 2003; received in revised form 7 July 2003; accepted 9 September 2003

Abstract

The inclination of the joint line after supracondylar osteotomy of the femur for valgus deformity was studied in 22 patientsand 26 knees. The patients(four males and 18 females) were 17–77 years old(mean, 49.5 years). The obliquity of the joint linewas measured in positive degrees(medial inclination) and negative degrees(lateral inclination). Mean obliquity wasq3.18 inthe pre-operative study andy2.08 in the post-operative study. A more horizontal joint line was obtained following surgicaltreatment(mean correction: 5.08).� 2003 Elsevier B.V. All rights reserved.

Keywords: Valgus deformity; Supracondylar osteotomy; Joint line

1. Introduction

Several investigators consider evaluation of the obliq-uity of the joint line to be important in the study ofgenu valgumw5x. Closing wedge tibial osteotomy forvalgus deformity frequently causes an increase in infer-omedial inclination w1,2,6,8–11,15x. In computerizedbiomechanical studies, Coventryw12x demonstrated thattibial osteotomy for deformity causes an increase injoint obliquity, thus transferring most of the load fromthe lateral compartment to the intercondylar eminenceof the tibia, with a consequent damaging affect on thejoint.Maquetw9x stated that the resultant of the forces that

act on the joint line will act in a perpendicular manneronly after supracondylar osteotomy for valgus deformity,with an even distribution through the tibial condyles.The objective of the present study was to show that

supracondylar osteotomy of the femur for valgus defor-

*Corresponding author.E-mail address: mariocarneiro@uol.com.br(M. Carneiro).

mity leads to a more horizontal joint line when thepatient is weightbearing.

2. Methods

Twenty-two adult patients were submitted to 26 inter-ventions for the correction of valgus axial deviationassociated or not with other pathologies. The patientsare registered in the Departament of Orthopedics andTraumatology of Universidade Federal de Sao Paulo-˜Escola Paulista de Medicina.Four patients (18.2%) were males and eighteen

(81.8%) were females, aged 17–77 years(mean ages49.5 years). Knees were involved in 4 patients(18.2%),the right knee was involved in 18(72.7%), and the leftknee in 6(27.3%).All patients were submitted to correction of the

deformity by supracondylar medial closing wedge oste-otomy of the femur using an anterior approach andlateral fixation with a 908 angle self-compressing plate.The valgus deformity was calculated for all patientsusing the femoral–tibial anatomical axis. Radiographicmeasurements were made through weight bearing films

320 R. Navarro, M. Carneiro / The Knee 11 (2004) 319–321

Fig. 1. Weight bearing radiograph showing pre-operative obliquity ofthe joint line. a – line parallel to the ground. b – line parallel to thetibial condyles determines the joint line obliquity. Medial obliquitydetermines a positive angle.

Fig. 2. Weight bearing radiograph showing post-operative obliquityof the joint line. a – line parallel to the ground. b – line parallel tothe tibial condyles determines the joint line obliquity.

on bi-pedal stance. After the degree of deformity wasmeasured, the wedge was calculated so as to yield a 58

valgus femoro–tibial anatomical axis. The obliquity ofthe joint line was measured in positive degrees to medialinclination and negative degrees to lateral inclination(Fig. 1). Mean pre-operative obliquity ranged fromy3to q188 (meansq3.18) (Table 1).Data were analyzed statistically by the non-parametric

Wilcoxon test (T satistic) for two dependent samplesaccording to Siegelw7x to compare the pre-operativeand post-operative periods in terms of the variable understudy. The level of significance was set ataF0.05.

3. Results

Post-operative obliquity ranges fromy7 to q78(meansy28); the Wilcoxon test showed that the post-operative values significantly lower compared to pre-operative values(Table 1) (Fig. 2)

4. Discussion

In the past, osteotomy for the correction of genuvalgum was preferentially performed on the tibia. How-ever, starting in the 1960s, biochemical studies and theevaluation of long-term results led surgeons to begin toindicate osteotomy in the supracondylar region of thefemur w1,13,14,16–18x.Our objective was to achieve a correction that would

provide a femoro-tibial angle with valgus of approxi-mately 58, as recommended by Shoji and Insallw4x andCoventryw3,12x.Mean pre-operative obliquity wasq3.18 and mean

post-operative obliquity wasy2.08. The mean differ-ence between the pre-operative and post-operative per-iods was 5.18, i.e. a lateral rotation of the joint lineoccurred. The Wilcoxon test showed that post-operativevalues were significantly lower than pre-operative val-ues, confirming the facts that supracondylar osteotomyof the femur for valgus deformity produced horizontally

321R. Navarro, M. Carneiro / The Knee 11 (2004) 319–321

Table 1Patients submitted to supracondylar osteotomy of the femur for valgusdeformity according to number of order and valgus(degree) of jointline obliquity during the pre-operative and post-operative periods anddifferences between periods

Patient number Pre-operative Post-operative D

obliquity Obliquity

1 0 y2 22 q2 y2 43 0 0 04 q3 0 35 q4 q1 36 q2 y3 57 q3 y3 68 0 y4 49 q4 y3 710 q4 0 411 y3 y6 312 0 y4 413 q12 q7 514 q2 y2 415 q8 0 816 q3 y2 517 q3 y4 718 0 y2 219 q18 y7 2520 0 0 021 q3 y2 522 q2 y4 623 0 0 024 q3 y5 825 q4 y1 526 q4 y4 8Mean q3.1 y2.0 5.1

Wilcoxon test: calculated T O ; critical T 73 before-after.*

of the joint line. This results in proportional redistribu-tion of the forces that act on the medial and lateralcompartments of the knee and represents one of thefavorable consequences of this type of surgery.

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