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Malalignment of the Lower Extremity

Malalignment of the Lower Extremity Overview

Bow-Legged or Knock-Kneed

One of the common risk factors to a knee injury is a genetic or congenital malalignment of the lower extremity. Bow-legged (varus) and knock-kneed (valgus) are two well-known conditions associated with improper lower extremity alignment. Many individuals have a malalignment but it does not lead to any significant knee injuries or conditions. Dr. Brian Waterman is trained and experienced at treating patients with lower extremity alignment injuries.

Proper alignment of the knee is important for normal function and balance of the joint. In a properly balanced knee, the body’s weight is transferred evenly through the middle of the joint. When the knee is not balanced and perfectly straight, a knee injury can occur from a weight overload on one side. Common problems that occur with unbalanced lower extremity alignment are osteoarthritis, ligament tears, meniscal tears and chondral defects.

There are two types of malalignment of the lower extremity that can cause a knee injury. They are called varus and valgus.

  • Varus (bow-legged): The majority of the body’s weight passes through the inside (medial) portion of the knee. This condition is worsened in many cases by overuse and obesity.
  • Valgus (knock-kneed): The majority of the body’s weight passes through the outside (lateral) portion of the knee.

Malalignment of Lower Extremity Symptoms

Malalignment is often visually noticeable in patients standing or walking. Leg alignment is highly variable the general population, and only requires treatment if symptoms are noted, or if associated with other painful knee conditions such as cartilage damage or ligament injury. If the condition is left untreated, pain, inflammation and swelling may occur.

Malalignment of Lower Extremity Diagnosis

In order to diagnose an unbalanced lower extremity alignment, Dr. Waterman will perform a physical examination to assess the malalignment and evaluate for a knee injury. He will look at how weight is distributed and how the knee is balanced while the patient is in a standing position. Full length standing X-rays will be performed in most cases to determine the extent of the condition and help determine proper treatment.
Malalignment of Lower Extremity Treatment


Dr. Waterman commonly begins lower extremity alignment injuries with non-surgical measures. Patients may be asked to lose weight, modify shoes, modify activities, brace the knee with an unloader brace and perform lower extremity strengthening exercises to help treat the condition and symptoms.


If non-surgical measures fail or if a knee injury is associated with the malalignment, Dr.Waterman may recommend surgery. Lower extremity alignment injuries can be addressed by a number of surgical options, including an osteotomy, total knee replacement (arthroplasty) and a unicompartmental knee arthroplasty. In many cases, an osteotomy may be combined with other procedures to treat a knee injury. For example, in patients with a malalignment and an ACL tear, Dr.Waterman will perform the osteotomy to correct the malalignment and then perform the ligament reconstruction to treat the ACL knee injury.

When an osteotomy is required, a cut in the bone is made to allow the alignment of the bone to be corrected. Once manipulated to the normal position, the bone is fixed with a plate and screws.   Additional bone (bone graft) either from the patient or a donor, or a bone substitute is used to facilitate healing.

Before surgery is performed, Dr.Waterman will explain each procedure and help the patient determine the correct option based on extent of injury, patient’s activity level and patient’s age.

At a Glance

Dr. Brian Waterman, MD

  • Chief & Fellowship Director, Sports Medicine, Wake Forest
  • Team Physician, Wake Forest University, Chicago White Sox
  • Military affiliation/Decorated military officer and surgeon
  • Learn more

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