Surgical management of medial knee osteoarthritis (OA) is controversial because of the young age and high activity level of many patients.17 Enthusiasm for the use of high tibial osteotomy (HTO) has declined,37 dampened by the consistent 10-year survival rates greater than 90% of both total knee arthroplasty (TKA)28,29,33,35 and unicompartmental knee arthroplasty (UKA).5,24
The main concern about TKA for young and active patients is the potential adverse effect of high joint reactive forces on the durability of the polyethylene insert.9 One biomechanical study suggests running and jumping produce surface loads that exceed the limits of polyethylene.9 Running produces contact forces of twice bodyweight, while deep knee bending can produce patellofemoral joint reactive forces approaching eight times the body weight.30
Therefore, HTO remains an attractive conservative procedure to avoid or delay a knee prosthesis.13,16,18 After HTO, many sporting activities (eg, running or jumping) may be possible at least for the first decade after surgery.25 Several factors may affect the postoperative result of HTO including age, gender, weight, degree of OA, and preoperative or postoperative angles.2,6,13,16
We ascertained survival of the HTO and patient satisfaction, and then evaluated the influence of perioperative factors on the outcome.
MATERIALS AND METHODS
We retrospectively reviewed 313 patients (372 knees) treated with a closing wedge HTO for varus deformity from May 1975 to December 1990. The mean age was 42 years (range, 15-76 years) (Fig 1). There were 194 males (62%) and 119 females (38%). The osteotomy was performed in 194 right knees and in 178 left knees. The mean body mass index (BMI) was 24.9 (range, 18.9-42). The average patient weight was 74 kilos (range, 42-116 kilos). We used Ahlback's classification to assess the presence of preoperative OA.3 There were 240 knees with Grades 1 (64%), 101 knees with Grade 2 (28%), and 31 knees with Grade 3 (8%). The mean preoperative varus tibiofemoral angle was 6° (range, 3°-15°). At the time of final followup (average, 18 years; range, 12-28 years) 27 patients (30 knees) died for reasons unrelated to the surgery and 29 patients (41 knees) were lost to followup, leaving 257 patients (301 knees).
We determined the amount of a closing wedge osteotomy preoperatively on a full limb standing anteroposterior view. The angle of the laterally based wedge was determined so the line connecting the femoral head center and the center of the ankle would cross the tibial plateau somewhere between the center of the lateral joint surface and the tibial spine eminence. The closing wedge HTO was performed through an anterolateral incision with the patient in supine position with a tourniquet. We performed a neck oblique fibular osteotomy after locating the peroneal nerve with the knee in slight flexion. The lateral tibial osteotomy was then performed using two oscillating saw blades or two osteotomes placed at the angle of the predetermined osteotomy. A drill was used to progressively weaken the medial cortex and the leg was then brought into valgus. The osteotomy was fixed with a Blount staple and an AO half-tube plate with three screws (Fig 2). The mean operative time was 55 minutes (range, 25-120 mm). The mean blood loss was 258 mL (range, 57-496 mL).
The postoperative rehabilitation included an immediate full motion program and early weightbearing protected by crutches for 45 days.
Patient satisfaction was evaluated at the time of followup grading the efficacy of the operation in relieving pain and improving function, as previously described,25 and the patients were asked to rank the result of the procedure as enthusiastic, satisfied, no change, or disappointed.
We used postoperative radiographic anteroposterior (AP) and a frontal full view of the lower limbs in weightbearing to measure the postoperative femorotibial angle and assess the presence of OA according to Ahlback's classification.3 All the radiographic evaluation was performed by a single clinician (XF) independent from the operating surgeons.
The probability of failure was estimated as a function of time using the Kaplan-Meier survivorship method with a 95% confidence interval (CI). Comparisons of survival curves were made with log-rank tests. Univariate and multivariate Cox proportional hazards model analyses were used to verify the relationship between survivorship and each possible associated factor (age, gender, BMI, preoperative tibiofemoral angle, preoperative Ahlback grade, and postoperative tibiofemoral angle). We performed a hazard ratio estimation to evaluate the association between risk of failure and contributing factors.
At final followup 43 knees (14%) were considered failures and underwent revision: 20 to TKAs and 13 to UKAs, with an additional four patellofemoral arthroplasties, four dé-bridements, and two tibial tubercle medializations. The average time from HTO to revision was 102 months. Considering revision as an endpoint for failure, the survival rate was 94.8% ± 1.2% at 5 years, 92.8% ± 1.5% at 10 years, 89.7% ± 1.7% at 15 years, and 85.1% ± 2.4% at 20 years.
Ninety-eight patients (33%) ranked their subjective score as enthusiastic, 133 (44%) as satisfied, 22 (7%) with no change, 44 (15%) as disappointed, and four patients (1%) did not answer. The mean onset for patient dissatisfaction was 170 months.
Factors protecting the outcome included an age at surgery less than 50 years (p = 0.014), a BMI less than 25 (p = 0.02), a knee with a preoperative Ahlback Grade 1 (p = 0.01), and a postoperative valgus angle of greater than 6° (p = 0.02) (Table 1). We found no correlation with gender or preoperative varus deformity. The average degree of postoperative femorotibial angle was 4° ± 1.9° of valgus (range, 0°-10°) (Fig 3). For the nonrevised knees, the postoperative radiographic analysis at the time of followup showed a remaining varus deformity for 171 knees (66%) in 141 patients with a mean femorotibial angle of 5° ± 1.9° (range, 1°-12°) and a valgus deformity for 87 knees (34%) in 80 patients with a mean femorotibial angle of 3° ± 1.9° (range, 1°-10°). According to Ahlback's classification,3 113 knees were Grade 1 (43%), 18 were Grade 2 (7%), 96 were Grade 3 (38%), 26 were Grade 4 (10%), and five were Grade 5 (2%) (Fig 4).
Ten patients (3.3%) had a postoperative complication: two had deep venous thrombosis (DVT), three had reflex sympathetic dystrophies, one had an infection requiring a débridement without hardware removal, two had fixation failures with subsequent additional internal fixation, one had delayed bone union and underwent bone grafting with internal fixation, and one had peroneal nerve palsy that resolved in 18 months. None of the these 10 patients underwent another revision at the time of followup.
Despite the great advances in knee arthroplasty, high tibial osteotomy remains a treatment option for medial moderate osteoarthritis of the knee, especially for the young and active population.17,23,32 However, many factors may influence the outcome such as age, gender, BMI, preoperative arthritis grade or preoperative and postoperative femorotibial angle.2,3,6,13 To help clarify current indications for HTO we ascertained whether various clinical or radiographic factors influenced the outcome.
We note several limitations. Our long-term study was not prospective and included some variations in surgical indications and techniques with surgery performed by several surgeons. The outcome was based primarily on the survival of the procedure at the time of followup and not any functional score. The other limitations of this study include the absence of sequential evaluation of the postoperative femorotibial angle and the absence of intraobserver variations of the radiographic analysis. Nonetheless, we had a relatively high percentage of patient followup and surgical revision is a clear endpoint.
Our findings, with a survival of 92% at 10 years and 85% at 20 years, compare favorably with the previously published results ranging from 75% to 90% at ten years.11,17,25,34 We found a 77% satisfaction rate after an average followup of 18 years. Using patient dissatisfaction as the endpoint, Sprenger et al found a 65% success rate at 10 years.34 Huang et al showed the probabilities of not experiencing failure with patient dissatisfaction as the endpoint were 80% at 10 years and 52% at 15 years.17 Nagel et al stated 82% of the 34 patients evaluated after an average duration of followup of 8 years after closing wedge HTO would have the operation again given the same situation.25
In our study patients older than 50 years had a failure rate 2.1 times more (p = 0.014) than patients younger than 30 years. Although the ideal age has not yet been determined (range, 50-65 years), younger patients have better long-term results.18,23,36 Other studies support this finding.6,18,26 Naudie et al showed patients older than 50 years had ½ the median survival time of patients younger than 50 years.26 Other authors have shown no difference in survival rate according to age.8,13,32
Gender did not influence the outcome in our study. Aglietti et al analyzed 120 closing wedge HTOs for varus knee OA performed in 102 patients at an average followup of 15 years (range, 10-21 years) and established male gender correlated with better results.1 This was not confirmed by Cass et al, who did not found any correlation with age or gender.10 They found the angle of correction to be the most important influencing factor.10
Body mass index could also influence the clinical outcome.16,22 We found a BMI of less than 30 protective. Giagonoudis et al examined 112 knees in 94 patients after HTO for varus and valgus gonarthrosis and suggested patients with a BMI of more than 10% above normal had a pain-free period of 5 years, whereas patients with a BMI of less than 10% above normal had a pain-free period of 7.8 years.15 This finding has not always been confirmed by other investigators.13,17,27,34
The role of preoperative OA on the result of HTO remains controversial. Osteoarthritis rated Grade 2 or more had a higher risk of failure. Twenty-three of the 31 knees (74%) classified Ahlback Grade 3 preoperatively required a revision at a mean followup of 16 years. This has been confirmed by several studies,2,6,19 while it was not the case in the study by Bahn and Dave.7 Despite the positive effect on pain relief, it seems HTO does not protect against the progression of medial arthrosis after a followup greater than 15 years.22,31 This corresponds well with the 50% of Ahlback Grade 3 or more after an average followup of 18 years.
Some studies have shown the preoperative angle could influence the long-term success of high tibial osteotomy.2,7,17 Huang et al analyzed a group of 93 high tibial closing wedge osteotomies performed in 82 patients and found a prognostic cutoff angle of 9°.17 However, this limit has not been precisely determined and should be for Bermann et al of 12° or less.6 We found no influence of the preoperative angle on the outcome after high tibial osteotomy, but the preoperative varus femorotibial angle was moderate (average, 6°). We believe the correct indication for this procedure should be the presence of a bony deformity with a tibial metaphyseal varus.
The recommended degree of valgus femorotibial alignment after HTO has ranged from 5°-14°.2,4,8,16,19 Akatamasu et al4 performed a bone mineral density study using dual x-ray absorptiometry in 144 knees with medial OA and found the ideal postoperative angle after HTO was 10° valgus. Conversely, Billings et al8 found overcorrection did not reduce the need for revision to a TKA. We found a postoperative limb alignment close to 6° valgus was a prognostic factor influencing favorably the outcome.13,21 We also believe a reasonable postoperative valgus axis is well accepted cosmetically by the patient and may also avoid number of operative difficulties reported for TKA after overcorrected HTO.
The ability to preserve the proper postoperative alignment is linked to the surgical technique and the fixation device.14,20 We did not find any additional complications with the use of a plate as previously described.12,34 The results of the closing wedge HTO technique were similar to other long-term results with a closing wedge technique,17,26,31,34 showing its ability to maintain the correction with limited complications related to nonunion. Medial opening wedge HTO using porous hydroxyapatite may represent an attractive option to avoid autografting.20
Our data suggest the ideal candidates for closing wedge HTO are patients with minor medial femorotibial OA (Ahlback Grade < 3) and younger than 50 years. For these patients with active lifestyle, we believe proximal tibial osteotomy remains an appropriate option.
The authors wish to thank Vanessa Pauly and Alexa Pierre from the department of medical computer science for their assistance in the statistical analysis of the study.
1. Aglietti P, Buzzi R, Vena LM, Baldini A, Mondaini A. High tibial valgus osteotomy for medial gonarthrosis: a 10- to 21-year study. J Knee Surg
2. Aglietti P, Rinonapoli E, Stringa G, Taviani A. Tibial osteotomy for the varus osteoarthritic knee. Clin Orthop Relat Res
. 1983;176: 239-251.
3. Ahlback S. Osteoarthrosis of the knee: a radiographic investigation. Acta Radiol Diagn (Stockh)
4. Akamatsu Y, Koshino T, Saito T, Wada J. Changes in osteosclerosis of the osteoarthritic knee after high tibial osteotomy. Clin Orthop Relat Res
5. Argenson JN, Chevrol-Benkeddache Y, Aubaniac JM. Modern unicompartmental knee arthroplasty with cement: a three to ten-year follow-up study. J Bone Joint Surg Am
6. Berman AT, Bosacco SJ, Kirshner S, Avolio A Jr. Factors influencing long-term results in high tibial osteotomy. Clin Orthop Relat Res
7. Bhan S, Dave PK. High valgus tibial osteotomy for osteoarthritis of the knee. Int Orthop
8. Billings A, Scott DF, Camargo MP, Hofmann AA. High tibial osteotomy with a calibrated osteotomy guide, rigid internal fixation, and early motion: long-term follow-up. J Bone Joint Surg Am
. 2000; 82:70-79.
9. Burstein AH. Biomechanics of the knee. In Insall JN, ed. Surgery of the Knee
. New York: Churchill Livingstone; 1984:21-39.
10. Cass JR, Bryan RS. High tibial osteotomy. Clin Orthop Relat Res
11. Coventry MB. Upper tibial osteotomy. Clin Orthop Relat Res
. 1984; 182:46-52.
12. Coventry MB. Upper tibia osteotomy for osteoarthritis. J Bone Joint Surg Am
13. Coventry MB, Ilstrup DM, Wallrichs SL. Proximal tibial osteotomy: a critical long-term study of eighty-seven cases. J Bone Joint Surg Am
14. Flamme CH, Kohn D, Kirsch L, Hurschler C. Primary stability of different implants used in conjunction with high tibial osteotomy. Arch Orthop Trauma Surg
15. Giagounidis EM, Sell S. High tibial osteotomy: factors influencing the duration of satisfactory function. Arch Orthop Trauma Surg
16. Hernigou P, Medevielle D, Debeyre J, Goutallier D. Proximal tibial osteotomy for osteoarthritis with varus deformity: a ten to thirteen-year follow-up study. J Bone Joint Surg Am
17. Huang TL, Tseng KF. WM, Chen WM, Lin RM, Wu JJ, Chen TH. Preoperative tibiofemoral angle predicts survival of proximal tibia osteotomy. Clin Orthop Relat Res
18. Insall JN, Joseph DM, Msika C. High tibial osteotomy for varus gonarthrosis: a long-term follow-up study. J Bone Joint Surg Am
19. Ivarsson I, Myrnerts R, Gillquist J. High tibial osteotomy for medial osteoarthritis of the knee: a 5 to 7 and 11 year follow-up. J Bone Joint Surg Br
20. Koshino T, Murase T, Saito T. Medial opening-wedge high tibial osteotomy with use of porous hydroxyapatite to treat medial compartment osteoarthritis of the knee. J Bone Joint Surg Am
. 2003; 85:78-85.
21. Mabrey JD, McCollum DE. High tibial osteotomy: a retrospective review of 72 cases. South Med J
22. Majima T, Yasuda K, Katsuragi R, Kaneda K. Progression of joint arthrosis 10 to 15 years after high tibial osteotomy. Clin Orthop Relat Res
23. Matthews LS, Goldstein SA, Malvitz TA, Katz BP, Kaufer H. Proximal tibial osteotomy: factors that influence the duration of satisfactory function. Clin Orthop Relat Res
24. Murray DW, Goodfellow JW, O'Connor JJ. The Oxford medial unicompartmental arthroplasty: a ten-year survival study. J Bone Joint Surg Br
25. Nagel A, Insall JN, Scuderi GR. Proximal tibial osteotomy. A subjective outcome study. J Bone Joint Surg Am
26. Naudie D, Bourne RB, Rorabeck CH, Bourne TJ. The Insall Award: survivorship of the high tibial valgus osteotomy: a 10- to -22-year followup study. Clin Orthop Relat Res
27. Pfahler M, Lutz C, Anetzberger H, Maier M, Hausdorf J, Pellengahr C, Refior HJ. Long-term results of high tibial osteotomy for medial osteoarthritis of the knee. Acta Chir Belg
28. Ranawat CS, Boachie-Adjei O. Survivorship analysis and results of total condylar knee arthroplasty: eight- to 11-year follow-up period. Clin Orthop Relat Res
29. Rand JA, Ilstrup DM. Survivorship analysis of total knee arthroplasty: cumulative rates of survival of 9200 total knee arthroplasties. J Bone Joint Surg Am
30. Reilly DT, Martens M. Experimental analysis of the quadriceps muscle force and patello-femoral joint reaction force for various activities. Acta Orthop Scand
31. Rinonapoli E, Mancini GB, Corvaglia A, Musiello S. Tibial osteotomy for varus gonarthrosis: a 10- to 21-year followup study. Clin Orthop Relat Res
32. Rudan JF, Simurda MA. Valgus high tibial osteotomy. A long-term follow-up study. Clin Orthop Relat Res
33. Scuderi GR, Insall JN, Windsor RE, Moran MC. Survivorship of cemented knee replacements. J Bone Joint Surg Br
. 1989;71: 798-803.
34. Sprenger TR, Doerzbacher JF. Tibial osteotomy for the treatment of varus gonarthrosis. Survival and failure analysis to twenty-two years. J Bone Joint Surg Am
35. Stern SH, Insall JN. Posterior stabilized prosthesis: results after follow-up of nine to twelve years. J Bone Joint Surg Am
. 1992;74: 980-986.
36. Waugh W. Tibial osteotomy in the management of osteoarthritis of the knee. Clin Orthop Relat Res
37. Wright J, Heck D, Hawker G, Dittus R, Freund D, Joyce D, Paul J, Young W, Coyte P. Rates of tibial osteotomies in Canada and the United States. Clin Orthop Relat Res