High tibial osteotomy is an alternative to knee replacement in the 40-65 year age group with early knee arthritis. It is also a surgical technique to protect delicate cartilage and meniscal work, and can help to improve some ligament laxities.
What is high tibial osteotomy?
High tibial osteotomy (HTO) is a surgical procedure to improve limb alignment by cutting a wedge into the upper end of the tibia bone - usually an opening wedge - and then plating the area to hold the limb in the new position. A bone graft may be used to fill the gap or the plate may simply hold the wedge open until the body fills the gap with new bone.
High Tibial Osteotomy. Lee DC and Byun SJ. Knee Surg Relat Res. 2012 Jun; 24(2): 61–69.
Indications for high tibial osteotomy
The most common indication is to unload one area of the knee where limb alignment problems have put excessive force on the joint cartilage, causing early cartilage damage. A less common indication is a change of limb alignment in order to protect a different structure, such as a partially torn posterior cruciate ligament or a cartilage graft. Finally it may be indicated where trauma (an accident) has led to damage and poor limb alignment.
High Tibial Osteotomy: A Systematic Review and Current Concept. Sabzevari S, Ebrahimpour A, Roudi MK and Kachooei AR. Arch Bone Jt Surg. 2016 Jun; 4(3): 204–212.
Medial opening wedge high tibial osteotomy
The most common kind of high tibial osteotomy is a medial opening wedge. This is the usual correction for a varus or bow-legged deformity, but in reality experienced osteotomy surgeons use digital computer planning on weight-bearing (standing) long leg X-rays . Using software they measure both the existing angular deformity and the degree of angular correction required to improve the mechanical weight-bearing axis. The software will indicate if the correction can be achieved by wedging in the tibial alone, or if the femur should be wedged also (a distal femoral osteotomy).
VIDEO OF TECHNIQUE by Dr Bhushan Sabnis
Realignment osteotomy for bow legs
Bow legs are particularly relevant when talking about osteotomy. Bow legs may be congenital (one is born with the problem) or acquired (the deformity develops over time). Congenital bow legs are usually managed by surgeons who focus on cosmetic orthopaedics including straightening and limb lengthening in patients who have no pain but are uncomfortable with their deformity. In the context of high tibial osteotomy it is really the acquired form of bow legs that we are talking about here, often the result of previous meniscectomy. One of the big issues of severe bow legs is the rehabilitation, and the surgeon may choose to do a simultaneous bilateral HTO so that rehabilitation of the one leg is not hampered by bowing in the other.
High tibial osteotomy and ligament instability
The ligament surgeon understands that some patients with residual ligament instability after reconstructive surgery may become more stable if the slope of the tibial plateau is changed, without needing to further interfere with the ligament itself. An HTO procedure can change not only the coronal but also the sagittal plane of the knee , ie not only as viewed from the front but also from the side. Most high tibial osteotomies are performed in the coronal plane, but modification in the sagittal plane has a significant impact on biomechanics and joint stability. This kind of osteotomy is called a slope-changing osteotomy, and is particularly relevant to problems of the posterolateral corner of the knee.
Here is a different case involving ligament injury, and in which an HTO was appropriate.
Role of high tibial osteotomy in chronic injuries of posterior cruciate ligament and posterolateral corner. Savarese E, Bisicchia S, Romeo R, and Amendola A. J Orthop Traumatol. 2011 Mar; 12(1): 1–17.
The Role of Osteotomy for the Treatment of PCL Injuries. Novaretti JV, Sheean AJ, Lian J, De Groot J and Musahl V. Curr Rev Musculoskelet Med. 2018 Jun; 11(2): 298–306.
High tibial osteotomy in the ACL-deficient knee with medial compartment osteoarthritis. Herman BV and Giffin JR. J Orthop Traumatol. 2016 Sep; 17(3): 277–285.
High tibial osteotomy and meniscal transplant
In more proactive units focusing on regenerative orthopaedics, tibial osteotomy may be planned as an adjunct to medial meniscus transplant to shift the weight-bearing line away from the damaged area and give the new meniscus an adequate chance to integrate and function.
High Tibial Osteotomy + Mensicus Transplant - Complete Fracture! Forum discussion.
Is a high tibial osteotomy painful?
Traditionally this was acknowledged to be a painful procedure, followed by three uncomforable months struggling with crutches. As techniques improved, including minimally-invasive techniques, and the tools and fixation plates improved, together with improvements in long-acting local anaesthesia infiltration and regional nerve blocks, the procedure may be rendered much less painful and no worse than any other knee procedure. Bone-grafting the open wedge may also speed up healing amd reduce pain.
High tibial osteotomy pros and cons
The important consideration regarding HTO is that the procedure avoids entering the knee joint itself. No joint tissue is removed or replaced. If the procedure is being done to avoid damage to the joint cartilage surfaces it means that the forces through the knee can be improved, but it leaves open a later option for a partial or total knee replacement if things do not work out. Because the plate is generally removed a year or so after surgery, the bone below the joint is not really compromised either. However, rehabilitation does take time as the bone has to fill any wedge gap and then consolidate and become strong again, and this takes time.
In those cases where the osteotomy is being performed to improve the chances of success of a cartilage graft (chondral or osteochondral graft) or a meniscus replacement then it may greatly improve the final outcome for the patient, despite adding an uncomfortable procedure and rehabilitation to the primary operation.
Modern osteotomy has few complications. The dreaded complication is infection, but this is nowadays rare. There may also be scarring in the anterior interval behind the patellar tendon, leading to stiffness - but this can usually be managed with appropriate physiotherapy.
High tibial osteotomy as an alternative to knee replacement?
HTO is most often considered as an alternative to joint replacement in the younger patient - probably 40 - 65 - who has significant one-sided (unicomparmental) joint damage but in whom the other side of the same joint is still in good shape. The most common choice nowadays is between an HTO and a partial knee replacement (unicompartmental knee replacement).
High tibial osteotomy plate removal
A year or so after the osteotomy has united, the surgeon may go back into the area through a small incision to remove the plate and screws. Most patients feel better after they have been removed. Without the hardware the bone can fully heal.