Intra-Articular Osteotomy for Genu Valgum in the Knee with a Lateral Compartment Deficiency

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1 100 COPYRIGHT Ó 2016 BY THE JOURNAL OF BONE AND JOINT SURGERY, INCORPORATED Intra-Articular Osteotomy for Genu Valgum in the Knee with a Lateral Compartment Deficiency Davi S. Felman, MD, Rachel Y. Golstein, MD, MPH, Aam M. Kurlan, BA, an Abel Maji Sheikh Taha, MD Investigation performe at the Division of Peiatric Orthopaeic Surgery, NYU Hospital for Joint Diseases, New York, NY Backgroun: A eficiency of the lateral compartment of the knee, often in the setting of skeletal ysplasia, is an intraarticular eformity resulting in genu valgum. Historically, this abnormality has been treate using an extra-articular approach. Lateral hypoplasia of the femoral conyle can be treate with avancement of the lateral femoral conyle without creating a seconary eformity. The purpose of this stuy was to present the technique an results of lateral conylar avancement, with or without tibial hemiplateau elevation, in patients with intra-articular valgus eformity seconary to skeletal ysplasia. Methos: A retrospective review of the cases of five patients, from seven to twenty-one years ol, with skeletal ysplasia an unilateral or bilateral severe genu valgum eformity was performe. For all patients, the etiology of the eformity was a eficient lateral compartment of the knee that is, lateral femoral conylar hypoplasia with or without concomitant lateral hemiplateau epression. Lateral femoral conylar avancement with or without lateral tibial hemiplateau elevation was performe in eight knees. Results: The average tibiofemoral angle was 34.7 of valgus preoperatively an improve to 9.4 of valgus at the most recent follow-up. The average length of follow-up was 2.9 years (range, 1.0 to 5.2 years). The average range of motion at the time of final follow-up was an arc of 108 starting from full extension. All osteotomies heale uneventfully. All five patients were satisfie with both the cosmetic appearance an the function of the involve limb an were able to walk without assistive evices. Conclusions: In patients with a eficient lateral compartment of the knee, lateral femoral conylar avancement with or without hemiplateau elevation allowe correction of severe genu valgum without the creation of an oblique joint line. This technique allows correction of the overall mechanical axis, restoring both function an the cosmetic appearance of the limb. Level of Evience: Therapeutic Level IV. See Instructions for Authors for a complete escription of levels of evience. Peer Review: This article was reviewe by the Eitor-in-Chief an one Deputy Eitor, an it unerwent bline review by two or more outsie experts. The Deputy Eitor reviewe each revision of the article, an it unerwent a final review by the Eitor-in-Chief prior to publication. Final corrections an clarifications occurreuring one or more exchanges between the author(s) an copyeitors. Genu valgum may arise from extra-articular eformities originating from the istal en of the femur or the proximal en of the tibia, intra-articular eformities originating from the femoral conyle or the tibial plateau, joint laxity, or a combination of these factors. A eformity resulting from an intra-articular etiology is often harer to manage. Lateral compartment eficiency of the knee, for example, originating from lateral conylar hypoplasia with or without lateral tibial plateau epression, poses a great challenge to the orthopaeic surgeon. This eformity occurs most commonly in patients with skeletal ysplasia. Knee pain an instability are the primary symptoms. There is, however, a paucity of literature outlining techniques for the correction of lateral eficiencies in the knee. Reporte techniques for correction of a Disclosure: None of the authors receive payments or services, either irectly or inirectly (i.e., via his or her institution), from a thir party in support of any aspect of this work. None of the authors, or their institution(s), have ha any financial relationship, in the thirty-six months prior to submission of this work, with any entity in the biomeical arena that coul be perceive to influence or have the potential to influence what is written in this work. Also, no author has ha any other relationships, or has engage in any other activities, that coul be perceive to influence or have the potential to influence what is written in this work. The complete Disclosures of Potential Conflicts of Interest submitte by authors are always provie with the online version of the article. J Bone Joint Surg Am. 2016;98:

2 101 hypoplastic lateral femoral conyle are largely irecte towar treating patellar instability 1,2. Opening-wege, closing-wege, anome metaphyseal osteotomies have been escribe for the treatment of the valgus knee. These are successful techniques for extra-articular eformities. Conylar eficiency with or without plateau epression must be aresseifferently. Employing extra-articular osteotomies to manage intra-articular abnormality will create an extra-articular eformity, an oblique jointwiththeresultantshearstresses,anoftenseconary instability. Historically, intra-articular correction of the joint has been use to treat severe tibia vara with meial tibial plateau epression 3-8. This proceure was reporte as early as 1964 by Langenskioel an Riska, who state that this osteotomy shoul be use when there is excessive varus of the knee cause by extreme sloping of the meial tibial plateau 9. This has eventually become part of the stanar metho of treatment for severe Blount isease. Paley escribe an intra-articular osteotomy of the femoral conyles to treat conylar eficiencies ue to neonatal sepsis 10. Genu valgum resulting from lateral femoral conylar hypoplasia with or without hemiplateau epression can be correcte by means of a similar technique. The purpose of the present report was to etermine the results anescribe the technique of lateral conylar avancement, with or without tibial hemiplateau elevation, in patients with intra-articular valgus eformity seconary to skeletal ysplasia. Materials an Methos The charts an raiographic stuies of five patients (eight knees) with skeletal ysplasia an severe genu valgum associate with knee pain an instability were reviewe retrospectively in this institutional review boarapprove stuy. Four patients ha pseuoachonroplasia, an one ha an unknown synrome with an absent patella. We are aware of no classification system that graes lateral compartment eficiency, largely because this abnormality is uncommon. We classifie the knees in our patients into two groups: types I an II. Type I inclue those with only isolate lateral femoral conylar eficiency, an type II inclue those with an associate lateral tibial plateau epression. Both groups require lateral femoral conylar avancement, but only type II require an aitional lateral tibial plateau elevation prior to conylar avancement. All five patients were female an range in age from seven to twenty-one years at the time of surgical intervention. Patients typically unerwent surgery after having reache skeletal maturity; however, one patient who ha a more complex eformity unerwent surgery prior to maturity. All eight knees ha at least one year of follow-up, with an average uration of 2.9 years (range, 1.0 to 5.2 years) (Table I). TABLE I Patient Demographics Case Age at Surgery (yr) Diagnosis Tibial Involvement Follow-up (yr) Complications Type I 1 17 Unspecifie skeletal ysplasia with severe subluxation, genu valgum, an hypoplastic lateral femoral conyle 2* 8 Unspecifie skeletal ysplasia with islocate an hypoplastic right knee with compression of the peroneal nerve 3* 7 Unspecifie skeletal ysplasia an severe eformity of the left knee with islocation of the knee an inability to walk 4 21 Pseuoachonroplasia an hypochonroplasia with severe valgus eformity of the right lower extremity 5 21 Pseuoachonroplasia with severe eformity of the left knee an valgus eformity with lateral conylar eficiency Type II 6 12 Pseuoachonroplasia an severe genu valgum 7 15 Pseuoachonroplasia an severe genu valgum 8 19 Pseuoachonroplasia with severe femoral conylar an lateral tibial plateau eficiency in the right knee as well as subluxation of the right knee in severe valgus No 1.0 None No 3.2 None No 3.9 Transient common peroneal nerve palsy No 1.0 Painful harware No 1.5 Painful harware Yes 5.1 None Yes 2.5 Meial propagation of the osteotomy intraoperatively Yes 5.2 None *Cases 2 an 3 were in the same patient. Cases 4 an 5 were in the same patient. Cases 6 an 7 were in the same patient.

3 102 Fig. 1-A Fig. 1-B Fig. 1-C Figs.1-A,1-B,an1-CCase 8. A patient with severe genu valgum seconary to lateral femoral conylar hypoplasia anepression of the lateral plateau. Fig. 1-A Clinical staning photograph. Fig. 1-B Staning anteroposterior raiograph emonstrating severe genu valgum with collapse into the lateral compartment an opening of the meial joint space. Fig. 1-C Varus stress raiograph emonstrating lateral femoral conylar hypoplasia an lateral plateau epression with the anatomic meial istal femoral angle an meial proximal tibial angle base on the healthy meial femoral conyle an meial tibial plateau. This raiograph emonstrates the amount of conylar avancement an lateral plateau elevation require for surgical correction. Preoperative Assessment Patients were examine to etermine the severity of the valgus eformity an instability. Staning raiographs were mae to evaluate the eformity (Figs. 1-A an 1-B). These raiographs may suggest meial collateral ligament insufficiency. Aitionally, a varus stress raiograph was mae to confirm the location of the eformity (Fig. 1-C). This view was the most important stuy in etermining the extent of the lateral plateau epression an femoral conylar hypoplasia.

4 103 TABLE II Raiographic Measurements Mechanical Axis Deviation (mm) Tibiofemoral Angle (eg) Lateral Conylar Deficiency (mm) Case Preop. Postop. Preop. Postop. Preop. Postop. Postop. aldfa* (eg) Type I Type II *aldfa = anatomic lateral istal femoral angle. The knee ha a rotatory subluxation. The preoperative mechanical axis eviation an tibiofemoral angle in one knee (Case 2) coul not be measure because of the rotatory subluxation an therefore the measurements are not inclue. Surgical Technique Patients were positione supine on a raiolucent table. An intraoperative arthrogram was performe prior to surgical correction in orer to confirm joint morphology. All arthrograms emonstrate a preserve meial compartment with a eficient lateral compartment seconary to hypoplasia of the lateral femoral conyle. In some knees, a epresse lateral tibial plateau was seen as well (Fig. 2). In these knees, a line tangent to the meial plateau was use to quantify the lateral epression. Once the extent of the eformity was etermine, the osteotomy was performe. An external fixator was applie, with two half-pins place into the proximal, lateral aspect of the femur an two pins place into the meial aspect of the tibia. The joint was then reuce into anatomic alignment, an the external fixator was ajuste to maintain this alignment while the osteotomies were performe. The joint line eformity was analyze to etermine the source of the gap in the lateral compartment of the knee. The line tangent to the meial plateau line was rawn. If this line passeirectly on the surface of the lateral plateau, then the lateral femoral conyle was the sole source of the valgus eformity. When the lateral plateau was epresse below this line, a lateral tibial plateau elevation was require. An incision was mae on the istal aspect of the thigh anterolaterally approximately 8 cm proximal to the proximal pole of the patella an was exteneistally to the proximal pole. The incision then curve posteriorly across the fibular neck, ening approximately 5 cm istal to the tip of fibular hea, allowing visualization an subsequent ecompression of the peroneal nerve, which was one routinely as part of the proceure. The nerve was ientifie anecompresse at the posterolateral aspect of the knee an was then trace aroun the fibular neck into the lateral compartment of the leg, an the lateral intermuscular septum was release. The iliotibial ban was isolate from the surrouning fascia, etache from its proximal soft-tissue attachments, an incise several centimeters proximal to the joint. The istal attachments were left intact, allowing for later reconstruction. The iliotibial ban was then peele away from the lateral aspect of the knee proximally to istally to provie better visualization of the lateral conyle. When eeme necessary, the lateral plateau elevation was performe through an extension of the aforementione incision. The proximal aspect of the fibula was osteotomize just istal to the tibiofibular joint at the level of the tibial plateau elevation. As the peroneal nerve ha previously been ecompresse in this region, the proximal tibiofibular joint was opene an externally rotate through the joint, exposing the lateral sie of the proximal part of the tibia. In aition to protecting the peroneal nerve, care was taken posteriorly to protect the anterior tibial artery as it traverse from posterior to anterior through the interosseous membrane. A Kirschner wire was use to guie the hemiplateau elevation. The osteotomy was performe with a Fig. 2 Intraoperative arthrogram confirming lateral femoral conylar hypoplasia an lateral plateau epression.

5 104 woun aequate time to heal before oing so. At six weeks, patients were permitte to bear weight as tolerate. A return to full activity was allowe at three months. Source of Funing There was no external source of funing. Fig. 3 Lamina spreaer in the transverse osteotomy site isplacing the osteotomize fragment istally. curve osteotome. The plateau was elevate, an an iliac-crest wege allograft was then use to fill the osteotomy site. The graft was maintaine in position with an antiglie screw an a washer. An anterolateral arthrotomy was performe to gain access to the lateral femoral conyle. A vertical osteotomy was then mae through the femoral notch. A corresponing extra-articular transverse osteotomy was mae approximately 3 to 4 cm proximally to form a so-calle box cut, creating a free fragment on the lateral aspect of the istal en of the femur consisting of the lateral femoral conyle. Care was taken to ensure that the horizontal limb of the osteotomy was extene only halfway across the with of the femur. To avoi evascularizing the free fragment, the lateral an posterior soft-tissue attachments were left intact. The free fragment was then avanceistally, utilizing the lateral tibial plateau as a guie for the amount of avancement require. Alignment of the limb was assesse on fluoroscopic images of the hip, knee, an ankle joints using the cautery cor, being certain to measure the meial proximal tibial angle an the mechanical lateral istal femoral angle 11 with the cor. A lamina spreaer was use proximally to maintain the avancement (Fig. 3). A rectangular iliac-crest allograft, approximately 30 to 45 mm in length, was then use to fill the resulting gap. Aequate joint line correction was confirme with fluoroscopy. The osteotomy was fixe with a five-hole 3.5-mm Limite Contact Dynamic Compression Plate (LC-DCP; Synthes), an a 6.5-mm cannulate screw was inserte from proximal-meial to istal-lateral or istal-lateral to proximal-meial for ae fixation (Fig. 4). The external fixator was then remove. Each knee was then taken through the range of motion, an an assessment of stability with varus an valgus stresses was performe. Overall alignment was also note both clinically an raiographically. Once stability was ensure an the mechanical axis was correcte, 5 ml of emineralize bone matrix putty was place aroun the lateral osteotomy site. The iliotibial ban was use as a fascial cover to protect the joint an harware, an an extra-articular rain was place to prevent postoperative hematoma formation. Postoperative Protocol Patients receive perioperative antibiotic prophylaxis for twenty-four hours. The rain was remove on postoperative ay 1 or 2, epening on output. The knee was immobilize in the immeiate postoperative perio. Foot-flat 30-lb (13.5-kg) weight-bearing with axillary crutches was allowe. On postoperative ay 7, range of motion as tolerate was initiate, allowing the Results All eight knees were treate with lateral femoral conylar avancement. Three knees also ha a lateral tibial hemiplateau elevation to correct an associate lateral proximal tibial epression. At the time of the most recent follow-up, all knees were able to achieve full extension. The average knee range of motion was an arc of 108 (range, 90 to 120 ), starting from full extension. The mechanical axis eviation 11 improve from an average of 66.4 mm (range, 6.2 to 122 mm) preoperatively to 10.5 mm (range, 3.6 to 38.1 mm) at the most recent follow-up. The tibiofemoral angle improve from an average of 34.7 (range, 6 to 70 ) of valgus preoperatively to an average of 9.4 (range, 0 to 17 ) atthemost recent follow-up. The average lateral conylar eficiency was 12.5 mm (range, 2.4 to 24.2 mm) preoperatively an 0.46 mm (range, 0 to 3.7 mm) postoperatively. The average anatomic lateral istal femoral angle at the time of the most recent follow-up was 84.6 (range, 80 to 88 ) (Table II). Type-II Fig. 4 Intraoperative raiograph emonstrating the complete hemiplateau elevation an lateral femoral conylar avancement after placement of harware.

6 105 TABLE III Tibial Raiographic Measurements in Type-II Knees Lateral Tibial Plateau Depression (mm) Case Postop. MPTA* (eg) Preop. Postop *MPTA = meial proximal tibial angle. Elevate MPTA was seconary to an extra-articular valgus eformity of the tibial metaphysis. knees ha an average meial proximal tibial angle of 94 (range, 89 to 101 ) 11 an an average hemiplateau epression of 1.1 mm (range, 0 to 3.2 mm) at the most recent follow-up. One type-ii knee (Case 6) ha an extra-articular valgus eformity of the proximal tibial metaphysis resulting in an elevate meial proximal tibial angle (Table III). Two knees (Cases 1 an 2) ha a rotatory subluxation. The preoperative mechanical axis eviation an tibiofemoral angle in one of these knees coul not be measure because of the subluxation an therefore it is not inclue in the relevant average measurements. All five patients were satisfie with both the cosmetic appearance an the function of the involve limb(s). All were able to walk without assistive evices at the most recent follow-up. Complications inclue a transient common peroneal nerve palsy in one knee in the immeiate postoperative perio that was manage with maintenance of the knee in flexion an resolve completely. Meial propagation of the osteotomy occurre intraoperatively in one knee an necessitate internal fixation of the meial metaphysis uring the inex operation. Two knees require removal of painful harware at an average of twelve months after the inex proceure (Table I). Discussion Genu valgum may occur seconary to lateral femoral conylar hypoplasia with or without lateral tibial hemiplateau Fig. 5 Preoperative staning anteroposterior raiograph using cutouts to emonstrate the results of both extra-articular lateral opening-wege (Fig. 5-A) an meial closing-wege (Fig. 5-B) osteotomies of the istal en of the femur, creating a eficient meial femoral conyle.

7 106 epression. Proceures for treating extensor mechanism instability by restoring the height of the lateral conyle an thereby eepening the femoral trochlea have been reporte. Marti an Beimers escribe an opening-wege osteotomy just proximal to the articular surface an angle towar the trochlea 2. This proceure allowe increase height of the lateral femoral conyle aneepening of the trochlea. In their series of eight patients, they foun that all of the osteotomies heale an the trochlear epth was improve. Puu et al. escribe an opening-wege lateral femoral osteotomy for the treatment of the painful valgus knee 12. This osteotomy was create in a slightly oblique irection, from proximal-lateral to istal-meial, with a 1-cm meial hinge. In their series of twenty-one patients, all ha improvement with respect to pain an knee function. However, in all of these cases, the entire istal en of the femur was in valgus, an simple correction of the mechanical axis was achieve with a istal metaphyseal osteotomy. For our patients, the rawback of the previously mentione proceures is that an extra-articular approach is use to aress an intra-articular eformity. As a result, these osteotomies are not optimum for intra-articular eformities because they create an oblique joint line an a eficient meial femoral conyle (Fig. 5); an intra-articular osteotomy was neee. Fig. 6 Postoperative raiograph showing correcte mechanical axis (ashe line) an mechanical axis eviation (soli line inicate by arrow) in the presence of hip subluxation. Performing raiographic analysis of the eformity for patients with a eficient lateral compartment poses a unique challenge as the anatomic an mechanical lateral istal femoral angles rely on normal femoral conyles an plateaus an so cannot accurately be measure prior to surgical correction. We suggest that the reliable measurements to assess this abnormality are the mechanical axis eviation an the anatomic tibiofemoral angle. Neither measurement is affecte by the eficiency of the femoral conyles or tibial plateau: the mechanical axis eviation relies on the hip an ankle joints (Fig. 6); the anatomic tibiofemoral angle is inepenent of the joint line, epening solely on the anatomic axes of the femur an the tibia. Assuming the meial femoral conyle is normal, we can rely on the anatomic meial istal femoral angle to evaluate the egree of femoral eficiency. This angle is assume to be 99 in a normal knee 11. Drawing this angle orients the surgeon to the extent of the lateral femoral conylar eficiency. More importantly, this angle efines the relationship of the meial conyle to the lateral conyle an can be use as another metho to measure the amount of lateral femoral conylar avancement that is require. The same analysis can be performe to assess lateral tibial plateau epression, using an angle of 88 between the anatomic axis of the tibia an the normal meial tibial plateau (Fig. 1-C) 11. Although all necessary information for joint analysis an eformity correction was obtaine from raiographs, arthrograms, an the varus stress raiographs, a compute tomography scan coul be utilize on a case-by-case basis if the surgeon believes it to be helpful in further preoperative planning. Lateral conylar avancement osteotomy for the treatment of valgus eformity an instability seconary to lateral femoral conylar hypoplasia has been mentione, as far as we know, only in the stuy by Paley on intra-articular osteotomies in the hip, knee, an ankle 10. To our knowlege, no stuy has investigate the results of this technique. We performe this proceure on eight knees in five patients, an all ha excellent clinical outcomes. Although the osteotomy was through the trochlear groove, the patients i not experience patellofemoral pain or subluxation postoperatively. Intra-articular osteotomies are technically emaning an may be prone to complications. A thorough preoperative analysis of the eformity shoul precee operative correction by this metho to ensure the best possible outcome an minimize the likelihoo of complications. The inications for correction shoul be clearly elineate. It is essential to etermine that the genu valgum is inee seconary to a eficient lateral compartment. An extra-articular osteotomy remains the primary option if it will achieve the esire correction without creating an oblique joint line or a eficient meial conyle. However, given the nature an location of this eformity, an extra-articular osteotomy woul likely fail to achieve these goals. Therefore, lateral femoral conylar avancement with or without lateral plateau elevation is necessary an is both a well-tolerate an effective

8 107 proceure for correction of genu valgum seconary to hypoplasia of the lateral compartment of the knee. n Davi S. Felman, MD 1 Rachel Y. Golstein, MD, MPH 2 Aam M. Kurlan, BA 1 Abel Maji Sheikh Taha, MD 1 1 Division of Peiatric Orthopaeic Surgery, NYU Hospital for Joint Diseases, New York, New York 2 Division of Peiatric Orthopaeics, Chilren s Hospital Los Angeles, Los Angeles, California aress for D.S. Felman: avi.felman@nyumc.org References 1. Weiker GT, Black KP. The anterior femoral osteotomy for patellofemoral instability. Am J Knee Surg Fall;10(4): Marti RK, Beimers L. Open-wege osteotomy of the lateral femoral conyle for extensor mechanism instability. Oper Orthop Traumatol Sep;18(3): Gregosiewicz A, Wośko I, Kanzierski G, Drabik Z. Double-elevating osteotomy of tibiae in the treatment of severe cases of Blount s isease. J Peiatr Orthop Mar-Apr;9(2): Schoenecker PL, Johnston R, Rich MM, Capelli AM. Elevation of the meical plateau of the tibia in the treatment of Blount isease. J Bone Joint Surg Am Mar;74(3): Jones S, Hosalkar HS, Hill RA, Hartley J. Relapse infantile Blount s isease treate by hemiplateau elevation using the Ilizarov frame. J Bone Joint Surg Br May;85(4): Hefny H, Shalaby H, El-Kawy S, Thakeb M, Elmoatasem E. A new ouble elevating osteotomy in management of severe neglecte infantile tibia vara using the Ilizarov technique. J Peiatr Orthop Mar-Apr;26(2): Janoyer M, Jabbari H, Rouvillain JL, Sommier J, Py G, Catonné Y, Colombani JF. Infantile Blount s isease treate by hemiplateau elevation an epiphyseal istraction using a specific external fixator: preliminary report. J Peiatr Orthop B Jul;16(4): Panya NK, Clarke SE, McCarthy JJ, Horn BD, Hosalkar HS. Correction of Blount s isease by a multi-axial external fixation system. J Chil Orthop Aug;3(4): Epub 2009 Apr Langenskioel A, Riska EB. Tibia vara (osteochonrosis eformans tibiae): a survey of seventy-one cases. J Bone Joint Surg Am Oct;46: Paley D. Intra-articular osteotomies of the hip, knee, an ankle. Oper Tech Orthop. 2011;21: Paley D, Herzenberg JE, Tetsworth K, McKie J, Bhave A. Deformity planning for frontal an sagittal plane corrective osteotomies. Orthop Clin North Am Jul;25 (3): Puu G, Cipolla M, Cerullo G, Franco V, Giannì E. Osteotomies: the surgical treatment of the valgus knee. Sports Me Arthrosc Mar;15(1):15-22.