Tibial tubercule osteotomy during medial approach to difficult knee arthroplasties

Transcription

1 Orthopaedics & Traumatology: Surgery & Research (2011) 97, ORIGINAL ARTICLE Tibial tubercule osteotomy during medial approach to difficult knee arthroplasties J. Tabutin, N. MorinSalvo, R. TorgaSpak, P.M. Cambas,. Vogt Cannes ospital Center, 15, avenue des Broussailles Cannes cedex, rance Accepted: 24 January 2011 KEYWORDS Total knee arthroplasty; Surgical exposure; Medial approach; Tibial tubercle osteotomy Summary Introduction: Osteotomy of the anterior tibial tubercle (TT) is well known as the approach to difficult knees, in particular those with a low patella, but it has a poor reputation. Patients and methods: This technique was used 21 times in 20 patients (10 males and 10 females) with a mean age of 71 years (range, years) for 14 prosthesis revisions (three for septic loosening, 11 for aseptic loosening) and seven knees that had not anteriorly received prior implants (three osteotomies, one synovectomy). The surgical technique included a long (7 cm), thick (> 1 cm) fragment retaining its lateral muscle hinge with compression fixation using two screws. In cases with a low patella, the TT was proximally displaced, with amplitude limited by the tibial baseplate. ollowup was clinical and radiological, lasting a mean 54 months (range, months). The clinical results were assessed using the IKS score and the radiological results using the measurement of the patellar index according to the protocol described during the Lyon Knee Days. Results: The mean preoperative IKS scores were: knee, 57.5 ± 22.4; function, 42.6 ± 21.5 (total, 100 ± 33.9); postoperative scores: knee, 84 ± 11.6; function 65 ± 28 (total, 149 ± 32.9). The joint range of motion increased from 73 ± 34.9 to 88 ± 21.1 for a mean gain of 15 ± We found a traumatic nondisplaced tibia fracture around a tibial stem, treated conservatively, two stress fractures of the immediate proximal part overhanging the TT with no consequences, one case of stiffness (not related to the osteotomy), and one case of localized skin necrosis on a knee that had undergone several surgeries (secondary scarring). No cases of malunion Corresponding author. Tel.: address: j.tabutin@chcannes.fr (J. Tabutin) /$ see front matter 2011 Elsevier Masson SAS. All rights reserved. doi: /j.otsr

2 Tibial tubercule osteotomy during medial approach to difficult knee arthroplasties 277 or migration of the TT were noted. The mean deliberate proximal migration obtained was 13 mm ± 6 (range, 8 33 mm). The patellar index increased from 0.18 ± 0.20 (range, 0.39 to 0.57) to 0.33 ± 0.19 (range, 0.13 to 0.60). Discussion: This series shows that the indications are rare but invaluable, facilitating the approach and most particularly making it possible to modify the position of the patella, thus contributing to increasing the joint range of motion. ixation with two screws carries no risk of disassembly if the technique is rigorous. Patellar translation is limited by the tibial tray. Type of study: level 4, retrospective study Elsevier Masson SAS. All rights reserved. Introduction Osteotomy of the tibial tubercle (TT) was suggested to improve exposure during knee surgery [1] and is used in total knee arthroplasty () when stiffness precludes appropriate eversion of the patella, whether it be related to primary disease or fibrosis in revision cases. This is undertaken even more readily when the patella is low or malaligned; repositioning the tuberosity improves the patellar index. The objectives of this study were to verify the feasibility of tubercle displacement and to describe any complications as well as to describe the relation between tubercle translation and patellar index improvement. Our hypothesis was that osteotomy of the TT with an anteromedial approach would remove the risk of patellar tendon rupture, that it could be done reproducibly, and that it would contribute to improving knee function in cases of patella baja. This article will not discuss TT osteotomy with an anterolateral approach in which the technical basis is similar, with the hinge represented by the medial periosteum [2]), performed systematically [3,4] or out of necessity [5,6]. Patients and methods The series rom 1993 to 2006, 21 TT osteotomies were performed in 20 patients (10 males and 10 females) with a mean age of 71 years (range, years) and a mean BMI of 25.5 ± 2.9 kg/m 2 (range, kg/m 2 ). During this period, 510 total knee arthroplasties were performed, 58 of which were revisions. The revisions were all performed via the anteromedial approach, as were 90% of the primary implantations. Seven cases involved a primary arthroplasty on stiff knees, two of which were after osteotomy and one after clearing the joint of septic osteoarthritis. ourteen cases involved prosthetic revision (12 first revisions, two second revisions): 11 for aseptic loosening and three for septic loosening, with the exchange done in two steps and the TT translation always performed in the second surgical session during prosthesis reimplantation. The indication for TT dislocation was selected for stiff knees in which the risk of patellar tendon rupture seemed substantial or with preoperative or predictable patella baja (e.g., exchanging a tibial insert for a thicker one) (ig. 1). Osteolysis was not a criterion for exclusion (ig. 2), but there was no massive osteolysis in the series. The description of the total series is presented in Table 1. Technique The operation was performed without a pneumatic tourniquet in all cases. or a knee that had already been operated, the original cutaneous incision was used and then in deeper tissues an anteromedial parapatellar approach between the rectus femoris muscle and the vastus medialis proximally and extended distally for approximately 10 cm below the TT. The distal line of the osteotomy was cut first with the oscillating saw between two small drill holes; then the frontal cut was made with a chisel (from medial to lateral; ig. 3). The bone flap had to be at least 1 cm thick and 7 cm long. Levering the bone fragment on the lateral musculoperiosteal hinge then gave excellent visualization of the joint. At the end of the intervention, releasing the lateral periosteum might be necessary to mobilize the bone fragment, but the muscle attachments had to be kept intact. ixation was ensured either in situ (two cases) or by modifying the position in medial or proximal translation (proximal, 19 cases). The transversal aspect of the distal osteotomy cut made it possible to use a distractor if the TT translation was difficult. The translation was limited by the distraction force or the upper edge of the fragment in relation with the prosthetic tibial baseplate. ixation was provided by two compression screws (ig. 4) going one side or the other of a keel or prosthetic intramedullary stem. Initially, the screws were metallic (the same alloy as that used for the tibial plate) (ig. 5). Since 1995, we have used resorbable screws in polylactic acid (Phusis, Saint Ismier, rance) initially with a round head (which required reaming in the TT). Since 2000, we have used a model with a flat head designed specifically for tubercle transpositions (Phusis). The material disappears progressively by hydrolysis [7]. The recovery period was conducted in the same way as for an implant without osteotomy: the knee at rest in a brace in extension, posture in extension, isometric work on the quadriceps, and spontaneous recovery of flexion. Preoperative stiffness did not alter the rehabilitation. Weightbearing was immediate for primary implant patients and differed for 3 weeks in prosthesis changes (determined by bone reconstruction). Evaluation The patients were seen regularly (2 months, 6 months, 1 year, then every 2 years) with a mean followup of 54 months ± We used the IKS score. Radiologically, we assessed the condition of the fragment (union, position)

3 278 J. Tabutin et al. igure 1 Multioperated knee: 1997, ; 2007, femoral fracture with retrograde nailing. Medial + lateral laxity + recurvatum; 2008, insert exchange (from 12 to 20 mm thick); TT translation, 15 mm. igure 2 Case no. 2. Tibial plate rupture due to osteolysis. Defect packed with bone substitute. TT translation, 13 mm. Resorbable screws. 7 years followup. ROM, 0/0/100 ; patellar index improved from 0.12 to and patellar height using the index described by Jacquot [8] during the 1999 Lyon Knee Days (ig. 6). This index has the advantage of not depending on the knee flexion angle, size or position of the patellar implant, length of the patellar tendon, tibial slope, or radiological enlargement. It has the disadvantage of lacking a published reference value. The statistical analysis was performed using the Mann Whitney test. Results We analyzed the results of the entire series, then the revision and primary subgroups. Complications Some complications were nonspecific of the tubercle osteotomy. One case of prepatellar partial cutaneous necrosis (5 cm 2 ) on a knee having undergone several interventions healed by secondary healing. Stiffness (0/0/50 ) did not seem to be related to the TT osteotomy but had substantial pre and postoperative trophic impairment with the soft tissues highly infiltrated. A traumatic fracture of the tibia with an intramedullary stem, slightly displaced (underlying the osteotomy zone) healed with a longleg cast. owever, we observed two cases of a complication specific to the TT translation: a stress fracture of the proximal extremity of the bone fragment extending beyond the metallic tibial tray (ig. 7). Rest led to bone union and the disappearance of pain in 2 months.

4 Table 1 Patient Sex Age P1 85 P2 80 P3 42 P4 81 P5 50 P6 54 P7 62 P8 90 P9 69 P10 82 Description of total series. Diagnosis Previous surgery Intervention U Preop IKS TTO indication TT elevation MTA IV VTO patella baja 11 mm MTA IV R 13 mm VNPS R 17 mm PIE Expo 11 mm MTA II Septic arthritis relapses Infected change in 2 steps R Expo 15 mm IE+PIE 14 mm TCA IE Patella baja 16 mm TCA TCA MTA II 1 2 Emslie 1 infected 2 PE 3 ablation R 9mm Internal trans Patella baja 11 mm R Expo 15 mm Postop IKS Preop ROM Postop ROM Patella index Knee unction Total Knee unction Total Preop Postop /95 0/ /90 0/ /110 0/ /50 5/ /75 0/ /90 0/ Complications /90 0/ Septic arthritis = 2step revision /90 0/ Tibial fracture around stemmed /85 0/ /30 10/ issure summit TTA Tibial tubercule osteotomy during medial approach to difficult knee arthroplasties 279

5 P11 63 P12 83 P13 65 P14 89 P15 71 P16 51 P17 a) 75 Table 1 (Continued) Polio.relapsesMTA 1 VTO 2 IE+PIE 33 mm MTA I R Expo 5 mm TCA 8 mm Internal trans MTA III R 16 mm Internal trans MTA III Patellar disl Internal trans ON 1 infected 2 ablation R Expo MTA IV R 12 mm /80 0/ /100 0/ /0 0/ /90 0/ Septic arthritis on = Synovectomy /120 0/ / Skin necrosis 48 m /100 0/ Tibial loosening 280 J. Tabutin et al.

6 P17 b) 71 P18 74 P19 79 P20 70 Table 1 (Continued) MTA III VTO Patella baja 11 mm MTA R 13 mm Septic arthritis relapses Synovectomy 23 mm racture relapses IE 18 mm Internal trans /110 0/ /110 0/ /20 0/ issure summit TT. Knee stiffness /120 0/ TTO: tibial tubercle osteotomy; RA: rheumatoid arthritis; MTA: medial femorotibial arthritis; : total knee arthroplasty; TCA: tricompartmental arthritis; R: revision of total knee arthroplasty; ON: osteonecrosis; IE: insert exchange; VTO: valgus high tibial osteotomy; PIE: patellar insert exchange; Expo, exposure; VNPS: villonodular hem pigmented synovitis; Trans: translation; Disl: dislocation; m, months. Tibial tubercule osteotomy during medial approach to difficult knee arthroplasties 281

7 282 J. Tabutin et al. igure 3 Distal stepcut osteotomy, proximal sloping, coronal from medial to lateral. Levering the fragment on its lateral hinge. igure 6 Patellar index (I/P) without prosthesis (left) and with a (right). Results of the overall series igure 4 ixation with two resorbable screws. Measuring tibial tubercle translation (double arrow). Clinical results The mean preoperative total IKS score was 100 ± 33.9 (range, ), with the knee score at 57.5 ± 22.4 (range, 5 88) and the function score at 42.6 ± 21.5 (range, 10 to 80). At 54 months followup, the mean total score was 149 ± 32.9 (range, ), with the knee score at 84 ± 11.6 (range, 43 95). The mean preoperative flexion was 78.8 (range, 0 120; standard deviation [SD], 36), at followup 88.6 (range, ; SD, 21.9) for a mean gain in flexion of 9.8 (range, 20 to 80 ; SD, 24.2). The mean extension angle decreased from 4 ± 7.3 (range, 10 to 20 )to 0.7 ± 2.2 (range, 0 10) for a gain in extension of 4 ± 7.2 ( 5 to 20 ). The joint range of motion increased from 73 ± 34.9 (range, )to88 ± 21.1 (range, ) at the followup, for a mean gain of 15 ± 23.6 (Table 2). igure 5 Case no. 13. Stiff knee after tuberculosis ( 10 /10). 1994, TT osteotomy necessary to expose for the. Two metallic screws. Judet quadriceps release at 6 weeks (the fixation was reliable). At 10 years, ROM, 0/0/80 ; patellar index, initially 0.23, 0.28 at followup.

8 Tibial tubercule osteotomy during medial approach to difficult knee arthroplasties 283 igure 7 Case no. 19. Overhang of the proximal part of TT. atigue fracture healed with relative rest. Table 2 Total series: analysis of the results. Patients Groups IKS gain Extension gain lexion gain PI gain 1 A B B A B B B B A B B B A B A B a) B b) A B A B Means Standard deviation Pvalues Radiological results We observed no malunion, necrosis, or secondary migration of the bone fragment, which showed union in a mean 3.5 months ± 1.6 (range, 1 6 months). The mean translation in the 19 cases in which the TT was displaced (ig. 4) was 13 mm ± 6 (range, 8 33 mm). The preoperative patellar index increased from 0.18 ± 0.20 (range, 0.39 to 0.57) to 0.33 ± 0.19 (range, 0.13 to 0.60) at followup, for a gain of 0.15 ± 0.78; there was no modification in the patellar index value between the immediate postoperative measurement and the followup measurement.

9 284 J. Tabutin et al. Primary and revision subgroup results The increase in clinical capacities and the gain in the patellar index were higher in the primary arthroplasty subgroup than in the revision subgroup [p (IKS gain) = 0.26; p (extension gain) = 0.20; p (flexion gain) = 0.43; p (IP gain) = 0.76] (Tables 3 and 4). Discussion ATT osteotomy is a rare indication (approximately 5% of the cases operated in the same period) during knee arthroplasty, but it facilitates the anteromedial approach in a stiff joint and allows modification of the patellar position by acting on the distal side of the extensor system. The major risk The major risk during the approach, in which sufficient patellar eversion is necessary for good exposure, is detachment of the patellar tendon from its tibial insertion, as highlighted by Bellemans [9] and Rand et al. [10], which can lead to an active extension lag and difficult locking of the knee, a difficult handicap to control. The extensor system The extensor system can be released distally (TT) or proximally. In 1943, Coonse and Adams [11] described the turndown of the patellar tendonpatellaquadriceps tendon group toward the front, with the proximal V sutured in a Y [12] to lengthen the extensor apparatus proximally. In 1984, Insall [13] modified these concepts by starting from a medial approach rising between the rectus femoris muscle and the vastus medialis to descend diagonally toward the superolateral angle of the patella. This quadriceps turndown levels the distal part of the extensor apparatus outward [14]. This proximal release is then reduced [15] with a simple proximal horizontal transection of the rectus femoris tendon, then finally a diagonal section upward and outward of this tendon, which can continue in the fibers of the vastus lateralis muscle in a quadriceps snip. Della Valle et al. [16] and Barrack [17] agree that the usual anteromedial approach is sufficient in more than 90% of the cases and that the quadriceps snip is only rarely necessary. This has no incidence on rehabilitation and in the end the strength of the quadriceps is equal to that of the contralateral knee with prosthesis although less than the normal knee [15]. On the other hand, osteotomy of the anterior tibial tuberosity acts on the distal part of the extensor system. Its lateral levering widely frees the joint and facilitates arthrolysis. Modification of the position of the bone fragment aims to improve patellar position, in particular in terms of height, which proximal release does not provide. Which bone block should be used? (variants and alternatives) Instead of an osteotomy, Lyu [18] performed an osteomyofascial flap, sutured to the medial periosteum. e observed only one failure out of 22 caused by forced flexion during a fall with a final 10 active extension defect. owever, is one certain to obtain a solid suture? A short bone fragment includes a risk of failure: those encountered by Wolff et al. [19] in 26 cases correspond to 3cm bone fragments with a minimal contact surface and insufficient fixation [19 22]. On the proximal side, we made a diagonal cut so as to raise the fragment. A stepcut tubercle osteotomy theoretically limits the risk of secondary displacement [5,23], but none were observed in the present study. On the distal side, progressive joining [23,24] weakens the tibia only minimally. A transversal osteotomy makes it possible to exert powerful mechanical distraction at the distal part of the fragment. owever, osteotomy may lead to a second fracture of the tibia promoted by substantial osteoporosis [25], mobilization under anesthesia [22], a neurological problem such as charcot s [20], or the extremity of an intramedullary stem at this level [26], a complication that we did not experience. Since the initial description by Dolin [1] in 1983, Della Valle et al. [16], ocking and Bourne [20], Laskin [27], Mendes et al. [21], Ries and Richman [22], Van den Broek et al. [23], and Whiteside [24] agree on the need for a sufficiently long bone fragment (> 6 cm) with several points that are sufficiently thick (>1 cm) so that the osteosynthesis does not weaken it (risk encountered in the series reported by Piedade et al. [28]), wide enough to provide a good contact surface to facilitate bone union. The fixation mode The fixation mode is debatable: Caldwell [30], Della Valle et al. [16], ocking and Bourne [20], Laskin [27], Mendes et al. [21], and Whiteside [24] use two or three wire or metal cable cerclages around an intramedullary stem for better hold. Arnold et al. [4], Burki et al. [3], and Van den Broek et al. [23] prefer screws, as we do. The proximal triangular section of the tibia makes it possible to pass them in or out of an eventual stem. The mechanical studies conducted by Davis et al. [29] demonstrate the superiority of this type of fixation. owever, the overhang of the screw heads can become painful and require secondary ablation [23]. The screws cannot be of the cancellous bone screw thread type (diameter, 6.5 mm): there would not be enough room between the cortical bone and the stem. Our practice has evolved toward a more sophisticated technology with resorbable screws with a flat head specifically designed for tubercle fixation. Their secondary resorption facilitates any ulterior revision. The final position of the TT The final position of the TT can be identical to the initial position: this is the simplification of the approach to a stiff knee [19] or this allows fixation or an allograft [20]. The tibial tubercle can be medialized to assist treatment for patellar instability [23] and it can be raised or lowered to modify the height of the patella [21,22]. In 19 cases of the present series, we raised the extensor apparatus a mean 13 mm (range, 8 33 mm). This raising is limited by the metallic tibial tray: a proximal process subjected to shearing can break when fatigued. Not having observed this princi

10 Tibial tubercule osteotomy during medial approach to difficult knee arthroplasties 285 Table 3 Primary subgroup: results analysis. Patients IKS gain Extension gain lexion gain PI gain b MEANS Standard deviations PI: patellar index. Table 4 Revision subgroup: results analysis. Patients IKS gain Extension gain lexion gain PI gain a MEANS Standard deviations PI: patellar index. ple, we encountered this complication, not yet reported in the literature, in two cases, with favorable progression following relative rest and no secondary migration of the fragment. Translation of the TT is a littleused option in the literature reports [21 24], with poorly specified indications. It is associated with a mean 15 gain in flexion (but this gain is multifactorial) and improvement in the patellar index, which has an incidence on the kinematics of the knee as soon as the level of the joint space varies [31]. Are there any contraindications to this TT osteotomy? We have encountered no contraindications in our practice. In cases of major proximal tibial osteolysis, there would be no bone to heal to the TT. This contraindication is relative for Mendes et al. [21]. ragility of the skin (age, corticotherapy, scarring from earlier interventions) is a relative contraindication [20,27]. The usual precautions, in particular the absence of subentaneous dissection, seems to have preserved our cases from extensive cutaneous necrosis. Strengths, weakness, and originality of this study This series is limited in the number of cases studied: 21 cases in 13 years, whereas Piedade et al. [28] described 126 cases in 7 years but only 18 anteromedial approaches. The other series range from 26 to 110 cases. We did not measure the strength of the extensor apparatus but clinically we observed no active extension defect. This is a retrospective and singlecenter study, like those in the literature. Translation of the TT is used most particularly in revisions (64 cases for Mendes et al. [21], 39 cases for Van den Broek et al. [23], 41 cases for Young et al. [33]), seldom in primary treatments (26 out of 136 for Whiteside [24], 18 medial approaches out of 126 for Piedade et al. [28], 11 out of 32 for Lavigne et al. [32]), and in our series in onethird of the cases. The literature reports few studies on patellar height [8,31]. Conclusion In surgery on difficult knees, during an anteromedial approach, osteotomy of the TT, even though it facilitates exposure in stiff knees, should not be considered simply as

11 286 J. Tabutin et al. an approach. One should know how to use it to modify the patella position. It reduces risks of patellar tendon rupture. With careful technique, its fixation and its hold are reproducible. It contributes to improving knee function in cases of patella infera. Disclosure of interest The authors declare that they have no conflicts of interest concerning this article. References [1] Dolin MG. Osteotomy of the tibial tubercle in total knee replacement: a technical note. J Bone Joint Surg Am 1983;65: [2] Ammari T, Zniber B, Boisrenoult P, Charrois O, Perreau M, Beaufils P. Patellar postion and lateral approach for total knee arthroplasty in degenerative knees with lateral femoropatellar arthrosis. Rev Chir Orhop 2005;91: [3] Burki, von Knoch M, eiss C, Drobny T, Munzinger U. Lateral approach with osteotomy of the tibial tubercule in primary total knee arthroplasty. Clin Orthop Relat Res 1999;362: [4] Arnold MP, riederich N, Widmer, Muller W. Lateral approach of the knee with tibial tubercle osteotomy (in german). Oper Orthop Traumotol 1999;11: [5] Keblish PA. Lateral approach to the valgus knee. Clin Orthop 1991;271: [6] Vielpeau C, ulet C, Tallier E, Locker B. The anterolateral approach for total knee replacement in arthritis with genu varum deviation (in french). Ann Orthop Ouest 2000;32: [7] Vert M. Chemical mechanism of the degradation of bioresorbable polymers derived from glycolic and lactic acid (in french). Actualités en biomatériaux, II. Paris: Romillat; pp [8] Jacquot L, Chatain, Casalonga D. Total knee arthroplasty and patella index (in rench). Montpellier: Sauramps Medical; pp [9] Bellemans J. Extension mechanism rupture after in «La prothèse du genou». Montpellier: Sauramps Medical; pp [10] Rand JA, Morrey B, Bryan RS. Patellar tendon rupture after total knee arthroplasty. Clin Orthop 1989;244: [11] Coonse, Adams J. A new operative approch to the knee joint. Surg Gynec Obstet 1943;321: [12] Trousdale RT, anssen AD, Rand JA, Calahan TD. VY quadriceps plasty in total knee arthroplasty. Clin Orthop 1993;286: [13] Insall JN. Surgical approaches to the knee: surgery of the knee. 1st ed. NewYork: Churchill Livingstone; p. 41. [14] Scott RD, Siliski JM. The use of a modified VY quadricepsplasty during total knee replacement to gain exposure and improve flexion in the ankylosed knee. Orthopedics 1985;8:45 8. [15] Garvin KL, Scuderig G, Insall JN. Evolution of the quadriceps snip. Clin Orthop 1995;321: [16] Della Valle CJ, Berger RA, Rosenberg AG. Surgical exposure in revision total knee arthroplasty. Clin Orthop Relat Res 2006;446: [17] Barrack RL. Specialized exposure for revision total knee arthroplasty: quadriceps snip and patellar turndown. J Bone Joint Surg Am 1999;81: [18] Lyu SR. Extensible exposure in revision total knee arthroplasty using an osteomyofascial flap in Techniques in knee surgery? Lippincott 2004;3: [19] Wolff AM, ungerford DS, Krackow KA, Jacobs MA. Osteotomy of the tibial tubercle during total knee replacement: a report of twenty six cases. J Bone Joint Surg Am 1989;71: [20] ocking RA, Bourne RB. Tibial tubercle osteotomy in revision total knee arthroplasty, in Techniques in knee surgery. Lippincott Edit 2007;6/2: [21] Mendes MW, Caldwell P, JIranek WA. The results of tibial tubercle osteotomy for revision total knee arthroplasty. J Arthropl 2004;19: [22] Ries MD, Richman JA. Extended tibial tubercle osteotomy in total knee arthroplasty. J Arthropl 1996;11: [23] Van den Broek CM, van ellemont GG, Jacob WC, Wymenga AB. Stepcut tibial tubercle osteotomy for access in revision total knee replacement. The Knee 2006;13: [24] Whiteside LA. Exposure in difficult total knee arthroplasty using tibial tubercle osteotomy. Clin Orthop Relat Res 1995;321:32 5. [25] Ritter MA, Carr K, Keating M, aris PM, Meding JB. Tibial shaft fracture following tibial tubercle osteotomy. J Arthopl 1996;11: [26] Arredondo J, Woland R, Jessup D. Non union after a tibial shaft fracture complicating tibial tubercle osteotomy. J Arthopl 1998;13: [27] Laskin RS. Ten steps to an easier revision total knee arthroplasty. J Arthropl 2002;17:8 82. [28] Piedade SR, Pinaroli A, Servien E, Neyret P. Tibial tubercle osteotomy in primary total knee arthroplasty: a safe procedure or not? The knee 2008;15: [29] Davis K, Caldwell P, Wayne J, Jiranek WA. Mechanical comparison of fixation techniques for the tibial osteotomy. Clin Orthop 2000;380:241. [30] Caldwell PE, Bohlen BA, Owen JR, Brown MM, arris B, Wayne JS. Dynamic confirmation of the fixation techniques of the tibial tubercle osteotomy. Clin Orthop 2004;424: [31] Chatain, Marin, Lavaste, Skalli W, Neyret P. Influence of the height of the joint space on the threedimensional kinetics of total knee prostheses and behavior of the lateral ligaments: an in vitrostudy. Rev Chir Orthop 2002;88: [32] Lavigne, Culpan P, Judet T, Piriou P. Osteotomy of the tibial tubercle in complex primary total knee replacement. Eur J Orthop Surg Traumatol 2009;19: [33] Young C, Bourne RB, Rorabeck C. Tibial tubercle osteotomy in total knee arthroplasty. J Arthropl 2008;23:371 5.