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High tibial open wedge osteotomy surgery

High tibial osteotomy surgery
Definition :
It is a joint preservation surgery to 
realigns the knee joint and preserving  the articular cartilage that has osteoarthritis and overloaded by malalignment. This surgery can delay or prevent the possible  need for a partial or total knee replacement (TKR). 

Principle of the high tibial osteotomy surgery:
In malalignment, unbalanced forces cause excessive loading on the medial or lateral portion of the knee joint.

 The combination of arthritis and malalignment can cause the articular cartilage tissues to wear on one side much more than the other in a progressive course.

Difference between High Tibial Osteotomy surgery  and total Knee Replacement surgery 
If the articular cartilage of the knee joint damaged beyond repair, total knee replacement (TKR) surgery can be the reasonable treatment of this case. 

But in certain less severe cases, a high tibial osteotomy surgery can unload and realign the knee to take the pressure off the damaged articular side by doing open wedge to the proximal tibia. 

Loading is then shifted away from the more damaged side and onto the more healthier side.

High tibial osteotomy surgery  is considered to delay the time before a total knee replacement is necessary and is typically reserved for younger patients with osteoarthritis pain resulting from malalignment. 

Is high tibial osteotomy a major surgery?Yes,  high tibial osteotomy is a major surgical procedure.

Preoperative Radiography

X rays 

AP, Lateral, long standing films to assess malalignment 

MRI

 to accurately assess the lateral compartment articular cartilage.

                                                                          Pre-operative planning of high tibial osteotomy surgery 

Weight-bearing axis (Mechanical axis):  A line drawn from the center of the femoral head to the center of ankle joint.weight-bearing ratio is calculated by measuring the distance from the medial edge of the proximal tibia to this line  divided by the entire width of the tibia.

Correction angle calculation of high tibial osteotomy surgery  

The ideal postoperative lower limb alignment is considered as 3°-5° of valgus from the mechanical axis. 

Some authors suggest that the post-operative mechanical axis should pass through the lateral one third of the tibial plateau. 

Other authors suggest that the degree of correction depends on the thickness of the  articular cartilage of the medial compartment.

 Dugdale et al suggested that the post-operative weight-bearing line should be located at 62.5% between the medial and lateral compartment of the proximal tibia.

Indications of HTO 

- an age between 40 and 70 years

- a knee flexion range more than 90° and, a lack of extension less than 10°

- non reducible deformity

- an active patient

- no contralateral femorotibial joint space narrowing or patellofemoral joint space narrowing

- significant symptomatic chondral injury to the patellofemoral or lateral compartments

Contraindications: 

- any inflammatory joint disease

- high BMI

- smoking

- Severe OA of the medial compartment

- total meniscectomy or osteoarthritis in the lateral or patellofemoral compartment

- a tibial subluxation more than 1 cm.

 - age more than 60 is a controversial contraindication.

- severe extra-articular deformity 


Technique of open wedge high tibial osteotomy surgery 

A diagnostic arthroscopy can be used to diagnose and treat intraarticular lesions.

 A five cm vertical incision is made over the center between the medial aspect of the tibial tuberosity and the posteromedial aspect of the proximal tibia. The pes anserinus insertion is detached from the tibia and a blunt retractor is inserted subperiosteally posterior to the tibia and also a subperiosteal dissection is performed from the tibial tuberosity to the posteromedial aspect of the tibia. 

Under C arm guidance, two guide wires or K wires are inserted at a point about 4 cm below the medial joint line and passed obliquely 1 cm below the lateral articular margin of the tibia towards the tip of the fibular head. 

Tibial osteotomy is performed just below the guide wires using an oscillating saw or an osteotome. The osteotomy extends from the medial cortex to one cm medial to the the lateral tibial cortex should be parallel to the posterior tibial slope.

Gradual vulgus force and 2 or 3 stacked osteotomes or calibrated wedge are used to open the osteotomy site. 

Once the desired degree of correction is achieved, internal fixation of a metal plate is performed. 

Spacer plates with metal block are identical to calibrate the wedge. 

What are the plates used for fixation of Open wedge high tibial osteotomy surgery??

Three plates for fixation of open wedge high tibial osteotomy: (A) Aescular plate, (B) Puddu plate, and (C) TomoFix plate
(D) T plate
(E) Spacer plates


Relationship between ACL or PCL injury and tibial slope

PCL injury and it's associated posterior tibial translation are accentuated by an increased tibial slope, while in an ACL injury and it's associated anterior tibial translation are accentuated by an decreased tibial slope.

How long does it take to recover from a high tibial osteotomy (HTO) surgery?

It generally takes about three months to recover. Immobilization using a cast or a brace is usually needed. Using a walker or crutches is mandatory as instructed. Closing wedge osteotomy may recover faster than open wedge high tibial osteotomy surgery. 

What is the success rate of high tibial osteotomy surgery? 

 High tibial osteotomy surgery is a reliable treatment option with satisfying clinical and functional outcome after 60 months of follow up. This surgery delays the necessity for TKA.
(Reference,  Bode G, von Heyden J, Pestka J, Schmal H, Salzmann G, Südkamp N, Niemeyer P. Prospective 5-year survival rate data following open-wedge valgus high tibial osteotomy. Knee Surg Sports Traumatol Arthrosc. 2015 Jul;23(7):1949-55. doi: 10.1007/s00167-013-2762-y. Epub 2013 Nov 19. PMID: 24241123.)

How long does the benefits of high tibial osteotomy surgery last?

The lasting effect of the surgery differs according to:
1- the preoperative degree of the articular cartilage damage.
2- Obesity
3- patient age
4- these benefits typically fade after 8 to 10 years.

What is the patient factors predictive of failure following high tibial osteotomy?

The greater patient age and body mass index (BMI) are generally associated with HTO failures.

What are the Risks & Complications of High tibial Osteotomy?
Infections, deep venous thrombosis, Injuries to blood vessels and nerves, Knee stiffness, implant failure, non union, over or under correction.





 











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