Distal Femoral Osteotomy
Osteotomies are a type of joint preservation surgery that aims to preserve the articular cartilage of the knee and prevent further joint breakdown or degeneration of the knee. When a patient has malalignment of the leg, either bowlegged (varus) or knock kneed (valgus) alignment, there can be an uneven distribution of forces through the knee joint causing unequal wearing on one side of the knee. Progressive wearing of the meniscus and cartilage on one side can cause osteoarthritis and pain only on that side of the knee. An osteotomy is used to realign a patient’s leg in order to relive pressure on the effected side of the knee joint and thus prevent further damage. It is an effective method in restoring a patient’s anatomy allowing for effective return to full activities. Furthermore, it is often used in conjunction with cartilage preservation procedures when malalignment exists simultaneously on both legs.
A distal femoral osteotomy is performed on a patient with knock kneed or valgus alignment.The normal anatomical load-bearing axis of the knee ranges from five to seven degrees of valgus. When the load-bearing axis is shifted further toward the outside of the knee as a result of this valgus alignment, it places increased force on the lateral compartment of the knee. Osteoarthritis pain may be vague in nature and related to repetitive, high-stress weight bearing activities such as running or jumping.
A detailed history will be taken upon initial visit as well as full standing x-rays of the legs in order to determine the alignment of the knees. From these x-rays, the angle of deformity and correction can be assessed. Surgical management and outcomes will be discussed at this time and a plan will be put into place.
Surgical management of osteoarthritis can involve many different options. An optimal candidate for a distal femoral osteotomy is a young, athletic, or acutely injured patient who has isolated lateral (outside of the knee) osteoarthritis. Patient’s age or activity level often exceeds the norm for knee replacement surgery and this procedure offers a better more effective alternative. Before surgery it is ideal that the patient has good range of motion and no ligament instability. Osteotomies can be performed in conjunction with other cartilage preservation or ligament surgeries.
The goal in performing a distal femoral osteotomy is to reduce knee pain by transferring weight-bearing loads from the outside to the inside of the knee when malalignment exists. In realigning the knee, the hope is to delay or eliminate the need for a knee replacement by slowing or stopping damage to the lateral joint compartment. Distal femoral osteotomies are performed by adding a wedge of bone to the outside portion of the femur just above the knee, adjusting the alignment to unload the affected lateral compartment, and then securing the position with a plate and screws. Successful long-term outcomes can be reached and prognosis improves with early intervention. The goal of this procedure is for the patient to successfully return to full functioning activity at 6 – 9 months with symptomatic improvement. A general guideline of osteotomy rehabilitation can be found within the Rehabilitation Protocols.
Dr. Klimkiewicz discusses this topic further in his talk entitled, Lower Extremity Alignment Solutions.