High Tibial Osteotomy - Henry Dushan Atkinson 22/1/2009

Opening wedge

Indications:

• Use in smaller angular corrections; avoids lateral dissection and fibular osteotomy
• Use in larger angular correction >12-15 degrees; avoids excessive shortening of tibia
• Use if MCL reconstruction or distal advancement is required
• Use in posterolateral corner (and FCL) reconstructions; as an intact proximal fibula is needed to anchor ligament grafts
• Use in patella alta or in the shortened tibia, where opening wedge positively affects the leg length

Disadvantages:

• Autograft/allograft required
• Varus collapse can occur due to delayed union (one can prevent this by using iliac crest bone (40 x 10 x 30 deep))
• Buttress plates can achieve more rigid fixation (Staubli AE, de Simoni C, Babst R. Tomofix: a new LCP-concept for open wedge osteotomy of the medial proximal tibia – early results in 92 cases. Injury 2003; 34(suppl2);b55-62)

• There is a greater chance of increasing the posterior slope if the plate is in an anterior position
• One often transects the superficial MCL distal attachment – in opening wedges of 5 - 7.5mm. This can be avoided by incompletely transecting the MCL at different levels effectively lengthening the ligament.
• In patella baja an opening wedge is contraindicated (it exacerbates the condition)

Pearls and pitfalls:

• Too proximal guide pin placement – can lead to lateral tibial plateau fracture
• Verify osteotomy at the medial cortex using anterior and posterior pins to check tibial slope.
• Dissect subperiostally to protect the superficial MCL
• Ensure fixation of the MCL to prevent valgus instability
• Iliac crest bone graft should be used for larger opening wedges
• Don’t osteotomise distal to the tibial tuberosity

Measurements:

• The anterior tibial gap should be half the postero-medial gap.
• Downsize the plate from the posteromedial coronal gap measurement
• Avoid obliquity of the osteotomy by keeping a 15-degree pin angulation to the tibial axis
• Avoid over-correction
• Begin immediate knee motion to avoid arthrofibrosis.
• Toe-touch WBing at 4/52.   Check WBing XR at 6-8 weeks.

Bone graft issues:

• Increased incidence of delayed and non-union when coral wedge used alone or with autologous BG (15%) c/w iliac crest graft (6%). (79)
• No problems with iliac crest graft;

Marti et al (32), (Pace TB, Hofmann AA, Kane KR, Medial opening high tibial osteotomy combined with Magnuscom intrarticular debridement for traumatic gonarthrosis. J Orthop Tech . 1994;2:21-28.),(Patond KR, Lokhande AV. Medial open wedge high tibial osteotomy in medial compartment osteoarthrosis of the knee. Nat Med J India . 1993;6:105-108)

Lots of mixed data on bone substitutes:

• No conclusive data on the effectiveness of any commercial triangular cortico-cancellous allografts (and rigid plates), and their union rates without loss of correction
• Porous HA wedges with fibular autograft – 100% union in patients with small corrections <10mm (24)
• Tricalcium phosphate graft led to 55% complications in 22 patients; 35% non-union, 15% loss of correction, 10% infection, 30% material failure!

Patt TW, Kleinhout MY, Albers RG. Paper #142. Early complications after high tibial osteotomy – A comparison of two techniques (open vs closed wedge) Arthroscopy 2003;19:74

• Use of bone cement in the posteromedial corner only, led to 99% union in 203 patients (12)  
• Apparently only a 2% delayed union and 2% loss of correction with locking plate used alone without any bone graft or substitutes in 92 patients. Though 40% needed metal-work removal

(Staubli 2003)

• 3% loss of correction using external fixation and 45% pin-tract infections in 33 patients

(Sterett WI, Steadman JR. Chondral resurfacing and high tibial osteotomy in the varus knee. Am J Sports Med . 2004;32:1243-1249), 38% PTI in 73 patients (80) and 51% PTI in 308 patients (29).

• No published data on the use of allograft bone

Closing wedge HTO

Advantages:

• Heals quicker and earlier WBing resumption (with the 2 large cancellous surface areas)
• Initial internal fixation is more secure than in opening wedge osteotomy: and thus less chance of loss of position/correction.

Disadvantages:

• More dissection required; Proximal fibular osteotomy; can lead to CPN injury
• Any intraoperative adjustments and secondary bony cuts are more time consuming
• In patella alta a closing wedge is contraindicated (it exacerbates the condition)

External fixation

• Allows for minor adjustments in difficult and multi-planar deformities
• But..... pin-tract infections are common over the 10-12 week fixation period

CPN injury (mixed data)

• 12% partial/complete CPN injuries reported in 1974. Mostly occurring with osteotomies distal to the tibial tuberosity (Jackson and Waugh 20)
• 7% (Sundaram 75), 6% (Harris and Kostuik 11).
• 0% in 137 cases of opening and closing wedge osteotomies

Noyes FR, Barber-Westin SD. Surgical reconstruction of severe chronic posterolateral complex injuries of the knee using allograft tissues. Am J sports Med . 1995;23:2-12,

Noyes FR, Barber-Westin SD, Hewett TE, high tibial osteotomy and ligament reconstruction for varus angulated anterior cruciate ligament-deficient knees. Am J Sports Med. 2000; 28:282-296.

Noyes FR, Mayfield W, Barber=Westin SD, Opening wedge high tibial osteotomy: an operative technique and rehabilitation program to decrease complications and promote early union and function, Am J Sports Med , 2006; 34:1262-1273)

Patella infra/baja

• Can occur due to a combination of quadriceps weakness, and contracture of the fat pad, leading to PFJ OA (Noyes FR, AAOS; 1991:233-247, Noyes FR, Clin Orthop 1991; 265:241-252)
• 80% develop patella baja after closing wedge. ? POP immobilisation causing quads relaxation and patellar tendon shortening (Windsor 82).
• 47% of 34 patients with POP immobilisation developed patella baja, c/w 8% of 35 patients who had immediate post-op CPM (Westrich 81)

DONT PUT THEM IN PLASTER!

Comparing the Opening wedge and Closing Wedge techniques

1) Posterior tibial slope decreases after closed-wedge high tibial osteotomy and increases after an open-wedge procedure because of the geometry of the proximal tibia. The changes in the slope are stable over time, emphasising the influence of the operative procedure rather than of the implant.

The effect of closed- and open-wedge high tibial osteotomy on tibial slope: 120 cases. H. El-Azab, A. Halawa, H. Anetzberger, MD, A. B. Imhoff, MD, S. Hinterwimmer. Journal of Bone and Joint Surgery - British Volume, Vol 90-B, Issue 9, 1193-1197.

2) Closing-wedge osteotomy achieves a more accurate correction with less morbidity, although both techniques had improved the function of the knee at one year after the procedure .

Osteotomy for medial compartment arthritis of the knee using a closing wedge or an opening wedge controlled by a Puddu plate: A ONE-YEAR RANDOMISED, CONTROLLED STUDY. R W Brouwer, S M A Bierma-Zeinstra, T M van Raaij, J A N Verhaar. Journal of Bone and Joint Surgery. (British volume). London: Nov 2006. Vol. 88, Iss. 11; pg. 1454.

Prospective RCT comparing two different techniques of high tibial osteotomy with a lateral closing wedge or a medial opening wedge, stabilised by a Puddu plate. The clinical outcome and radiological results were examined at one year. 92 patients were randomised to one or other of the techniques. At follow-up at one year the post-operative hip-knee-ankle angle was 3.4 degrees (+/- 3.6 degrees SD) valgus after a closing wedge and 1.3 degrees (+/- 4.7 degrees SD) of valgus after an opening wedge. The adjusted mean difference of 2.1 degrees was significant (p = 0.02). The deviation from 4 degrees of valgus alignment was 2.7 degrees (+/- 2.4 degrees SD) in the closing wedge and 4.0 degrees (+/- 3.6 degrees sd) in the opening-wedge groups. The adjusted mean difference of 1.67 degrees was also significant (p = 0.01). The severity of pain, knee score and walking ability improved in both groups, but the difference was not significant. Because of pain, the staples required removal in 11 (23%) patients in the closing-wedge group and a Puddu plate was removed in 27 (60%) patients in the opening-wedge group. This difference was significant (p < 0.001).

PFJ OA issues:

1) In patients who complain of pre-existing anterior knee pain, Distal OWHTO or CWHTO should be considered.

Patellofemoral contact pressure following high tibial osteotomy: a cadaveric study. Stoffel K, Willers C, Korshid O, Kuster M. Knee Surgery, Sports Traumatology, Arthroscopy, Volume 15, Number 9, September 2007 , pp. 1094-1100

Patella infera is a known complication of high tibial osteotomy (HTO) that can cause anterior knee pain due to excessive stresses associated with abnormal patellofemoral (PF) joint biomechanics. Nine fresh cadaveric knees underwent (1) medial opening wedge (OWHTO) with a proximal tuberosity osteotomy (PTO), (2) OWHTO with a distal tuberosity osteotomy (DTO), and (3) a lateral closing wedge (CWHTO). Compared to the intact knee, the DTO OWHTO and CWHTO did not significantly ( P > 0.05) influence PF pressure at any flexion angle.

Proximal OWHTO leads to a significant elevation in PF cartilage pressure at 30° ( P < 0.05), 60° ( P < 0.005), and 90° ( P < 0.0005) knee flexion. We conclude from these results that DTO OWHTO maintains normal joint biomechanics and has no significant effect on PF cartilage pressure .

2) In cases of severe PF-OA in which HTO was performed, ventralization of the tibial tubercle as combined surgery did not prove effective at the long-term follow-up .

Impact of patellofemoral osteoarthritis on long-term outcome of high tibial osteotomy and effects of ventralization of tibial tubercle. Majima T, Yasuda K, Aoki Y, Minami A. J Orthop Sci. 2008 May;13(3):192-7.

No consensus has been reached whether it is better to include treatment for the PF joint at the time of high tibial osteotomy (HTO), or if treatment of the PF joint is unnecessary.

The purpose of this comparative retrospective study on medial compartment OA of the knee accompanying PF-OA was to examine the effects of PF-OA on the long-term outcome of HTO and to evaluate the significance of ventralization of the tibial tubercle when combined with HTO.

We studied the impact of PF-OA on the long-term outcome of HTO and the effects of ventralization of the tibial tubercle, which was performed in conjunction with HTO for medial and PF compartment OA more than 10 years previously. The 42 subjects included 14 men (15 knees) and 26 women (27 knees). Their mean age at the time of surgery was 60.7 years, and the follow-up period was 10-15 years (average 12 years). Ventralization of the tibial tubercle was performed on 18 knees.

A significant relation was observed between improvement of the clinical knee score and preoperative radiological PF-OA stage in the HTO patients (P < 0.05). Radiologically, no correlation was observed between the shift in radiological PF-OA stage and the presence or absence of ventralization of the tibial tubercle. Among the preoperative radiological moderate and severe PF-OA cases, no significant relation was found between the presence or absence of ventralization of the tibial tubercle performed with HTO and improvement of the knee joint function score.

3) Valgus high tibial osteotomy increased the medial patellar tilt and reduced the medial patellar rotation. These effects were more profound after OWO. Patellar height significantly increased with CWO and decreased with OWO .

The influence of open and closed high tibial osteotomy on dynamic patellar tracking: a biomechanical study. Gaasbeek, R; Welsing, R; Barink, M; Verdonschot, N; Kampen, A. Source: Knee Surgery, Sports Traumatology, Arthroscopy, Volume 15, Number 8, August 2007 , pp. 978-984(7)

High tibial osteotomy (HTO) can cause alterations in patellar height, depending on the surgical technique, the amount of correction and the postoperative management.

Alterations in patella location after HTO may lead to postoperative complications. However, information on changes in dynamic patellar kinematics following HTO is very limited.

We conducted a biomechanical study, to analyze the effect of open (OWO) and closed wedge osteotomy (CWO) on patellar tracking. We studied the 3D dynamic patellar tracking in ten cadaver knees before and after valgus HTO. In each specimen, corrections of 7° and 15° of valgus according to, both, the OWO and CWO technique, were performed.

Both, OWO and CWO led to significant changes in the patellar tracking parameters tilt and rotation. We also found significant differences between OWO and CWO.

No significant differences were found for the effect on medial-lateral patellar translation. These observations can be taken into consideration in the decision whether to perform an OWO or a CWO in a patient with medial compartment osteoarthritis of the knee.

4) High tibial osteotomy with anterior advancement of the distal fragment successfully relieved patellofemoral symptoms of the patients with medial and patellofemoral compartmental osteoarthritis of the knee .

High tibial osteotomy with anterior advancement of distal fragment for medial and patellofemoral compartmental osteoarthritis of the knee. Saito T, Takeuchi R, Ara Y, Yoshida T, Koshino T. Knee. 2002 May;9(2):127-32.

High tibial osteotomy was performed in 73 knees of 50 patients with medial and patellofemoral compartmental osteoarthritis of the knee, which was combined with anterior advancement of the distal fragment.

At the operation, parapatellar release of the retinaculum and subperiosteal elevation of contracted medial soft tissue were also adjoined. The average age of the patients at the time of surgery was 64 years. The follow-up period was an average of 58 months. On overall clinical results assessed with the Knee Society score, the average total knee score was improved from preoperative 50 points to postoperative 94, and the preoperative average functional score of 47 points increased to 92 postoperatively.

At follow-up, pain from a grinding patella was not found in 68 of 73 knees and pain from grinding and deviating of the patella was relieved in more than 96% of all cases. The mean femorotibial angle was reduced from preoperative 185 degrees to postoperative 167 degrees. On skyline view, the width of the lateral facet joint space was widely opened postoperatively, particularly on the flexion angle of 90 degrees.

5) The high incidence of patella infera following medial opening wedge proximal tibial osteotomy may have deleterious effects on patellofemoral biomechanics or may complicate subsequent total knee arthroplasty .

Observations on patellar height following opening wedge proximal tibial osteotomy. Wright JM, Heavrin B, Begg M, Sakyrd G, Sterett W. Am J Knee Surg. 2001 Summer;14(3):163-73.

Pre- and postoperative Insall-Salvati ratios were 0.96+/-0.12 and 0.97+/-0.15, respectively (P=.30). The Insall-Salvati ratio decreased in 29% of patients, and no patient experienced a decline >0.07. The distance between the patella and tibiofemoral joint line ("patellar height") decreased in 100% of patients. The mean Blackburne-Peel ratio declined from 0.75+/-0.13 to 0.53+/-0.15 (P<.001). Sixty-four percent of the postoperative Blackburne-Peel values satisfied the radiographic criterion for patella infera (Blackburne-Peel ratio <0.54).

6) The angle of tibial inclination differed significantly between the two HTO techniques, increasing after opening-wedge HTO and decreasing after closing-wedge HTO.

There was no clinically-relevant difference in the intra- and interobserver variability of measurements of patellar height either before or after HTO.

Patellar height and the inclination of the tibial plateau after high tibial osteotomy. The open versus the closed-wedge technique. Brouwer RW, Bierma-Zeinstra SM, van Koeveringe AJ, Verhaar JA. J Bone Joint Surg Br. 2005 Sep;87(9):1227-32.

7) Combined lateral closing and medial opening-wedge high tibial osteotomy can provide good long-term outcomes because of the off-loading of the diseased medial compartment with minimal complications.

Combined lateral closing and medial opening-wedge high tibial osteotomy. Nagi ON, Kumar S, Aggarwal S. J Bone Joint Surg Am. 2007 Mar;89(3):542-9.

92 patients (ninety-four knees) had a high tibial valgus osteotomy. The average preoperative varus deformity was 13.5 degrees . The surgical technique consisted of a proximal lateral closing-wedge osteotomy and use of the lateral wedge as a graft on the medial side of the osteotomy. No internal fixation was used. A knee brace was used to maintain the 8 degrees to 10 degrees of valgus overcorrection. Seventy-two knees in seventy patients with at least fifteen years of follow-up were evaluated.

The mean initial postoperative correction (and standard deviation) for all knees was to 8.3 degrees +/- 2.7 degrees of valgus alignment. Survivorship analysis showed that the probability of survival (and 95% confidence interval), with conversion to total knee arthroplasty as the end point, was 100% at one year, 92% +/- 5.8% at ten years, 80% +/-7.7% at fifteen years, and 58% +/- 4.3% at twenty years.

The survivorship, with a Hospital for Special Surgery knee score of <70 points as the end point, was 80% +/- 4.5% at ten years, 72% +/- 5.6% at fifteen years, and 42% +/- 4.2% at twenty years. Twenty-six knees underwent an arthroplasty at an average of 15.6 years after the index procedure. For the forty-six knees that had not undergone an arthroplasty, the knee score improved from an average of 67 points preoperatively to 82 points at the time of the most recent follow-up.

8) Opening wedge HTO using autologous tricortical iliac bone graft with internal fixation and early mobilisation prevented change in posterior slope of tibia, lengthened the patellar ligament and elevated the tibiofemoral joint line when the mean ratio of anterior and posterior gap at the osteotomy site was around two-thirds

Tibial slope and patellar height after opening wedge high tibia osteotomy using autologous tricortical iliac bone graft. Chae DJ, Shetty GM, Lee DB, Choi HW, Han SB, Nha KW. Knee. 2008 Mar;15(2):128-33.

Our aim was to evaluate the alteration in angle of posterior slope of the tibia and the degree of patellar height following medial opening wedge high tibia osteotomy(HTO) using autologous tricortical iliac bone graft in 32 consecutive patients. Twenty three females and nine males underwent medial opening wedge high tibia osteotomy (HTO) using autologous tricortical iliac bone graft in 34 knees (33 primary medial compartment osteoarthritis and 1 idiopathic osteonecrosis of medial tibial condyle). The posterior slope of tibia was determined by the proximal tibial anatomical axis. Patellar height was measured by the Insall-Salvati and the Blackburne-Peel ratios. Preoperative and postoperative (last follow up) values of these three parameters were compared. The intra- and interobserver variability of these methods was determined before and after operation. At the end of mean follow up of 3 years this procedure produced no significant change in posterior slope. Pre and postoperative posterior slope were 8.7 degrees+/-3.6 degrees and 8.2 degrees+/-2.8 degrees respectively (P=0.412). Pre and postoperative Insall-Salvati ratios were 0.93+/-0.10 and 1.05+/-0.11 respectively (P<0.001). The Insall-Salvati ratio increased in 94% of patients and patellar ligament length was significantly increased. The distance between the patellar and tibiofemoral joint line decreased in 82% of patients. The mean Blackburne-Peel ratio declined from 0.71+/-0.12 to 0.61+/-0.13 (P<0.001). Twenty six percent of postoperative Blackburne-Peel values satisfied the radiographic criterion for patellar infera (Blackburne-Peel ratio<0.54). There was no difference in the intra-and interobserver variability of measurements either before or after HTO..

9) The high incidence of patella infera following medial opening wedge proximal tibial osteotomy may have deleterious effects on patellofemoral biomechanics or may complicate subsequent total knee arthroplasty .

Observations on patellar height following opening wedge proximal tibial osteotomy. Wright JM, Heavrin B, Begg M, Sakyrd G, Sterett W. Am J Knee Surg. 2001 Summer;14(3):163-73.

Patellar height and patellar ligament length were assessed pre- and postoperatively in 28 patients who underwent a medial opening wedge proximal tibial osteotomy for varus OA.

10) Distal tuberosity osteotomy in open wedge high tibial osteotomy appears effective in preventing patella infera.

  Distal tuberosity osteotomy in open wedge high tibial osteotomy can prevent patella infera: a new technique. Gaasbeek RD, Sonneveld H, van Heerwaarden RJ, Jacobs WC, Wymenga AB. Knee. 2004 Dec;11(6):457-61.

To prevent patella infera in open wedge high tibial osteotomy, a new operation technique was developed. Instead of a proximal tibial tuberosity osteotomy, a distal osteotomy was performed and the tuberosity was fixed with one screw to the tibia. Initial experience in 17 patients was evaluated and compared with results of 20 patients with open wedge high tibial osteotomy with proximal tuberosity osteotomy.

11 )Effects of patella alta and patella infera on patellofemoral contact forces. Singerman R, Davy DT, Goldberg VM. J Biomech. 1994 Aug;27(8):1059-65.  

The relationship between patella alta and patellar subluxation may, in part, reflect the relationship between the height of the patella above the tibiofemoral joint line and the patellofemoral contact force. The contact force was measured by a specially designed six-degree-of-freedom force transducer under loading simulating rising from a chair.

For a high-riding patella , the onset of tendofemoral contact is delayed and the magnitude of the patellofemoral contact continues to increase with increasing flexion angle . Early onset of tendofemoral contact associated with a low-riding patella results in a concomitant reduction in the magnitude of the contact force .

The medially directed component of the contact force acting on the patella resists lateral subluxation of the patella. This force component increased with superior displacement of the patella. This may explain in part the tendency for a high-riding patella to sublux.

For all seven specimens tested the point of application of the resultant contact force migrated superiorly with inferior displacement of the patella.

12) Although HTO was a good procedure for pain relief for dual-compartment disease, the addition of Maquet procedure did not improve the results.

High tibial osteotomy compared with high tibial and Maquet procedures in medial and patellofemoral compartment osteoarthritis. Nguyen C, Rudan J, Simurda MA, Cooke TD. Clin Orthop Relat Res. 1989 Aug;(245):179-87.

The effect of adding the Maquet tibial tubercle elevating procedure to a valgus high tibial osteotomy (HTO) in combined medial and patellofemoral disease had not been established. There was no statistical difference between the two groups in terms of mean postoperative femorotibial shaft alignment or clinical and roentgenologic outcome.