Rotational Deformity, Part 2

By: | Tags: | Comments: 0 | January 10th, 2014

Treating Rotational Deformity, Restoring Normal Leg Function

This is Part 2 of a previous blog on Rotational Deformity.

This condition is frequently misdiagnosed and can cause pain for years before a physician trained to identify the signs is able to correct the problem.

To the untrained eye, the subtle signs of Rotational Deformity may go undetected.

Childhood photo of patient showing visible malrotation.

Treating rotational deformity generally entails the use of several different osteotomy procedures. Osteotomy means bone cutting and entails a transverse bone cut just above or below a joint, shifting the malrotated lower limb segment to the known anatomic alignment, with immediate repair of the bone using a stable plate and screw construct. Since the cut is transverse, no bone is either added or removed, and the fixation is stable – accelerated rehabilitation is instituted.

Postoperative correction of rotational deformity.

The collective goal of these osteotomy procedures is to restore proper alignment to the lower limb, preventing degeneration (progressing to osteoarthritis), as well as correct the abnormality and establish anatomical correctness – restoring optimal leg function for patients wanting to return to an athletic or active lifestyle.

Each osteotomy procedure is designed to accomplish a different goal and are selected to repair an individual deformity when necessary:

  • Proximal Femoral Osteotomy typically used to repair an internal rotation deformity, commonly called anteversion or antetorsion that is greater than 30 degrees.
  • Proximal Tibial Osteotomy typically used to repair an external rotation deformity that is between 35 and 45 degrees.
  • Distal tibial and fibular osteotomy: commonly used to repair an external rotation deformity that is equal or greater than 45 degrees.
  • Osteotomy of the Tibial Tubercle: also known as patella alta, is occasionally necessary to repair a patella mechanism that causes the patella to ride to high and not engage its groove on the femur.

Derotational Proximal Femoral Osteotomy
A derotational proximal femoral osteotomy focuses on the realignment of the femur for purposes of obtaining anatomic alignment of the limb below the osteotomy, inclusive of the patella, leg, ankle, and foot. Typically, it will place the femoral groove (that articulates with the patella) directly under the patella.

A proximal femoral osteotomy is most commonly performed on younger people whose complaints are that of a deformity, and associated lower extremity problems inclusive of patella femoral pain and recurrent subluxation or dislocations. In these patients CT or MRI imaging will reveal antetorsion of 30 degrees or greater. A transverse cut made just below the hip is made and the rotation is reduced to 15 degrees with is the normal amount of antetorsion.

Proximal and Distal Tibial Osteotomy
The Proximal Tibial Osteotomy has also proven to be a safe and effective procedure. A proximal tibial osteotomy is most commonly performed on younger people whose complaints are that of a deformity and have associated lower extremity problems inclusive of patella femoral pain and recurrent subluxation or dislocations. In these patients CT or MRI imaging will reveal excessive external rotation of between 35 and 43 degrees. A transverse cut made just below the knee is made and the rotation is reduced to 23 degrees, which is the normal amount of external rotation.
A pre-contoured, low profile plate and screws are inserted to keep the osteotomy in place such that immediate rehabilitation can proceed – emphasizing knee range of motion and weight bearing.

The amount of correction possible with the proximal osteotomy is limited by the presence of the common peroneal nerve, which winds around the neck of the fibula. Rotation of the tibial osteotomy in excess of 20 degrees will cause stretching and dysfunction of this important nerve. Accordingly, when corrections of greater than 20 degrees are necessary, the osteotomy is performed nearer to the ankle, distal to where the motor branches from the peroneal nerve have already supplied their muscles.

Osteotomy of the Tibial Tubercle
An osteotomy of the tibial tubercle is a surgical procedure performed along with other procedures to treat patellar instability and patellofemoral pain, when the patella either rides too high or is inserted too lateral on the proximal tibia. A tibial tubercle transfer technique involves the realignment of the tibial tubercle (bump at the front of the shin bone) allowing the knee cap (patella) to traverse the center of the femoral groove. The patellar tracking is corrected by moving the tibial tubercle distally and/or medially, towards the inside portion of the leg. This removes the load from the painful portions of the knee cap.

A key component of this, as with any procedure, is established long before the patient arrives in the operating room. It is the thought process and plan that the patient and orthopaedic surgeon work up together, known as preoperative planning.

The orthopaedic surgeon first considers the complex deformities before proceeding with the procedure. After careful consideration, quantitative imaging (MRI or CT scan) including the hip, knee and ankle is performed so that measurements of rotation are accurately made.

Indications for repair include patients who are unable to live the life they want because of limb pain, instability, or deformity – and whose objective measurements fall far outside of the normal bell distribution. Surgery for correction is performed on all deformed bones at the same time, replacing the deformity with anatomic rotations that are at the 50% mark of normal range.

Although the risks associated with these osteotomy procedures are low, the most common complications include:

  • Infection
  • Blood clots
  • Stiffness of the knee joint
  • Injuries to vessels and nerves
  • Failure of the osteotomy to heal

Dr. Sanders and the Sanders Clinic staff take steps to dramatically reduce risk of complications, including:

  • Preoperative diet recommendations, lifestyle changes (cessation of tobacco, high protein diet, specified vitamins)
  • Use of spinal anesthesia, compression stockings, foot pumps and mechanical venous compression
  • Use of Platelet Rich Plasma (PRP) in wound healing
  • Testing and management of patient bacteria, addressing early susceptibility to infection and administration of preoperative antibiotics accordingly
  • Tourniquet to electrocoagulate small bleeding vessels, postoperative cold/compression dressing
  • Early resumption of movement

(Malalignments can cause a number of problems in the interconnected musculoskeletal system – from the neck and back to the foot and ankle. Proper diagnosis and correction is key to overall well being.)
View postoperative results from a left-leg rotational deformity repair.