1. HTO Complication M. Moghtadaei MD Associate Professor Iran University of Medical Sciences

2. Complication MOW,LCW,Dome,… –Over/Under correction –Joint line obliquity –Fracture –Nonunion –PF complications –Peroneal Nerve Palsy –Compartment Syndrome –Infection –Thromboembolism

3. COMPLICATION 5 - 34% ( 15.2 % ) smaller osteotomy gap size lower complication rate 10 mm is the threshold for most authors Nelissen EM, Langelaan EJ, Nelissen RGHH (2010) Int Orthop 34:217–223 Miller BS, Downie B, McDonough EB, Wojtys EM (2009) Arthroscopy 25:639–646

4. Over/Under correction Medial compartment load : 0 degree  70% 4 degree valgus  50% 6 degree valgus  40% recommended alignment 2 - 4 degree valgus or mechanical axis pass through 30 - 40% lateral to the midpoint of the knee

5. Over/Under correction Overcorrection to a valgus position might negatively influence the patients’ sport-specific and leisure activity levels 33

6. Recurrence of deformity Long-term studies –clinical success deteriorates with time –60% of patients at 10 years follow up Overcorrection

7. FRACTURES Medial or lateral cortex the proximal fragment may be destabilized Fractures must be appropriately reduced and stabilized

8. FRACTURES In articular surface is more severe complication because of resultant articular incongruity During both LCW and MOW

9. FRACTURES apex of osteotomy within 10 mm of the far cortex Leaving the proximal fragment at least 15mm thick gradual closure or opening of the osteotomy permits stress relaxation of the intact far cortex 15 mm 10 mm

10. FRACTURES

11. drill hole at the apex of the osteotomy increases the amount of correction obtained before cortical fracture Kessler OC, Jacob HA, Romero J: Clin Orthop 2002;395:180-185

12. fluoroscopy

13. NONUNION 1 - 5 % ( 2.2 % )

14. a better understanding of PFJ pressures and forces is important in long-term results Patellofemoral effect

15. Increased contact pressures an important factor in degeneration of articular cartilage Outerbridge RE.. J Bone Joint Surg Br. 1961;43:752-757 Skyhar MJ, Warren RF, Ortiz GJ, Schwartz E, Otis JC. J Bone Joint Surg Am. 1993;75:694-699

16. effects of HTO on PFJ –contact pressure –alteration of patellar height –PFJ tracking Stoffel K, Willers C, Korshid O, Kuster M. KneeSurg Sports Traumatol Arthrosc. 2007;15:1094-1100. Gaasbeek RD, Sonneveld H, van Heerwaarden RJ, Jacobs WC,Wymenga AB. Knee.2004;11:457-461 Kaper BP, Bourne RB, Rorabeck CH, Macdonald SJ. J Arthroplasty. 2001;16:168-173. Tigani D, Ferrari D, Trentani P, Barbanti-Brodano G, Trentani F. Int Orthop. 2001;24:331-334. Wright JM, Heavrin B, Begg M, Sakyrd G, Sterett W. Am J Knee Surg. 2001;14:163-173 Moghtadaei M. et al, IRCMJ, 2014 Patellofemoral effect

17. Contact Pressure MOW higher pressures in PFJ at different flexion angles increasing contact pressures with increasing angle of correction with MOW Huberti HH, Hayes WC. J Bone Joint Surg Am.1984;66:715-724 Singerman R, Davy DT, Goldberg VM. J Biomech.1994;27:1059-1065

18. Contact Pressure increased pressure further degeneration in an already painful, degenerative joint unsatisfactory clinical scores due to unresolved pain knowing how an HTO affects retropatellar pressures is a crucial step in decision making

19. Contact Pressure in symptomatic PF arthritis –HTO is abandoned in favor of TKA –combined with anterior (Maquet) or anteromedial (Fulkerson) transfer of the tibial tubercle Am J of Sport Med.;2013 Jan;41(1):80-6

20. Patellar Height LCW high incidence of patella baja A common misconception –patella baja because of rearrangement in osseous architecture following wedge removal results from contracture of patellar tendon Cast immobilization can be eliminated by rigid IF and aggressive mobilization Scuderi GR,Windsor RE, Insall JN: J Bone Joint Surg Am 1989;71:245-248 Westrich GH, Peters LE, Haas SB, Buly RL, Windsor RE: Clin Orthop 1998;354:169-174

21. Patellar Height changes in osseous architecture after LCW increase patellar height Wright JM, Heavrin B, Begg M, Sakyrd G, Sterett W: Am J Knee Surg2001;14:163-173

22. Patellar Height MOW lowers patellar height by raising the TFJ line 64% incidence of patella baja raises concerns regarding potential adverse impact on PF biomechanics Wright JM, Heavrin B, Begg M, Sakyrd G, Sterett W: Am J Knee Surg2001;14:163-173

23. Patellar Height Multiple studies documented patella infera following a MOW HTO increased retropatellar pressure and contact forces risk of knee pain and reduced ROM Gaasbeek RD, Sonneveld H, van Heerwaarden RJ, Jacobs WC,Wymenga AB. Knee.2004;11:457-461 Scuderi GR,Windsor RE, Insall JN: J Bone Joint Surg Am 1989;71:245-248 Stoffel K, Willers C, Korshid O, Kuster M. KneeSurg Sports Traumatol Arthrosc. 2007;15:1094-1100. Kaper BP, Bourne RB, Rorabeck CH, Macdonald SJ. J Arthroplasty. 2001;16:168-173. Stoffel K, Willers C, Korshid O, Kuster M. KneeSurg Sports Traumatol Arthrosc. 2007;15:1094-1100.

24. importance of considering PF arthritis and degeneration when an HTO is attempted

25. minimal disturbance of the patellar height minimally increased retropatellar pressures Stoffel K, Willers C, Korshid O, Kuster M. KneeSurg Sports Traumatol Arthrosc. 2007;15:1094-1100.

26. PFJ Tracking After MOW HTO –patella was lowered and tibia slope increased –patellar tilt and shift do not significantly change Yang JH, Lee SH, Nathawat KS,Jeon SH, Oh KJ. Knee ;2013 Mar;20(2):128-32

27. PFJ Tracking 43 patients open wedge HTO CT Scan –Congruence Angle,TT-TG before and after surgery Not significantly different(P > 0.05) Moghtadaei M. et al, IRCMJ, 2014

28. INFECTION 0.8 % - 10.4 % Superficial deep debridement and antibiotics If septic implant removal and use of external fixator

29. THROMBOEMBOLIC EVENTS DVT : 2 - 5 % = joint replacement Thromboprophylaxis similar to Knee arthroplasty

30. NERVE INJURY Peroneal 3.3 - 11.9 % Fibular osteotomy in LCW Postop may be related to increased pressure in anterior compartment

31. Vascular Injury must monitor for vascular injury –letting down the tourniquet if necessary a vascular surgeon must be available Some injuries may be detected postoperatively –Pseudoaneurysm

32. Thank You