Correction of Windswept Rotational Deformity with Fixator Assisted Plating Technique

Brief Clinical History:

This is a 54-year-old female who presented to our clinic with decreased ability to ambulate, chronic pain and a limb-length discrepancy. The patient was in a high-speed motor vehicle accident at age 17. She suffered proximal femur and pelvic fractures that subsequently required bilateral total hip replacement one year post injury. Since her index hip replacements she has had 11 revision surgeries. She has difficulty ambulating and walks like a crab. He lower extremities point in a direction that is about 45 degrees rotated from the direction that her pelvis faces.

Preoperative Clinical Photos and Radiographs:

• Figure 1: During physical examination, it was evident that the patient had a complex infrapelvic rotational deformity. In order to ambulate with her patellas facing forward, she rotated her pelvis in the opposite direction.
• Figure 2: Patient with a 5 cm block under the right foot, equalizing her pelvic heights, maintenance of her patellas forward elucidates counterclockwise rotational deformity of pelvis.
• Figure 3: Asking the patient to stand with her torso and pelvis facing forward, and a 5 cm block under the right foot, the complex rotational deformity is more apparent. External rotation deformity and shortening of the right lower extremity and left lower extremity internal rotation deformity of the lower extremity.
• Figure 4: Preoperative 51’’ erect leg hip to ankle X-ray. Patient has 5 cm block under the right foot. Left mechanical axis deviation (MAD) = 28 mm lateral; LDFA = 83°; MPTA = 91°; Joint line convergence (JLCA) = 0°. Valgus.
  Right: MAD = 25 mm lateral; LDFA = 84°; MPTA = 90°; JLCA = 2°. Valgus. LLD = 62 mm right side short.
• Figure 5a,b: CT rotational profile of bilateral lower extremities was obtained preoperatively. Calculations demonstrated 40° of external rotation, and 40° of internal rotation, of the right and left femurs, respectively. In addition, right tibia 15° external rotation.

Preoperative Problem List

1. Chronic pain
2. Status post bilateral revision component well-fixed total hip arthroplasties
3. Limb length discrepancy, 5 cm, right short
4. Right lower extremity valgus, femur origin, 11°
5. Left lower extremity valgus, femur origin, 10°
6. Right femur 40° external rotation deformity
7. Left femur 40° internal rotation deformity
8. Right tibia 15° external rotation deformity

Treatment Strategy

The femoral valgus and rotational deformities are approached first by staged bilateral distal femur osteotomies. Locking plates are utilized, and augmented with cables where screw fixation is comprised because of the long femoral stem. Once the coronal and axial planes are corrected a new 51’’ hip to ankle x-ray is used to assess limb length discrepancy. Tibial lengthening and residual axial malalignment is then performed.

Basic Principles

1. The magnitude of the coronal plane deformity can change as the rotational alignment is corrected. Be cognizant of this.
2. Distal femur osteotomy with fixator-assisted plating is a safe and accurate method to achieve coronal and rotational correction.
3. Osteotomy below well-fixed total hip femoral stems can be utilized rather than femoral stem revision, to correct rotational malalignment.
4. Since her hips are stiff, there is little ability for her to adjust the rotational deformity.

Images During Treatment:

• Figure 6: External fixator half-pins applied anteriorly and medially. Proximal half-pin (yellow-arrow) placed in neutral rotation.
• Figure 7: Maintaining the patella neutral, the proximal segment is externally rotated relative to distal segment the magnitude of the deformity (yellow-arrow). External-fixator secured once correction achieved, prior to plate placement.
• Figure 8: Bovie cord from center of femoral head to center of ankle can accurately assess intraoperative mechanical axis alignment.
• Figure 9: Clinical photograph post bilateral distal femoral osteotomy to correct rotation and valgus alignment.
• Figure 10: Patient returned to the operating room for lengthening of tibia and correction of external rotation deformity with Taylor-Spatial Frame using the lengthening and then nailing (LATN) technique.

Technical Pearls:

1. Use a distal femoral locking plate to allow for translation to occur with osteotomy is not at the CORA. Locking screws will ensure stability of the osteotomy when the plate is not adherent to the bone.
2. The external fixator application should not obstruct lateral locking plate application; place half-pins anterior and medial.
3. The external fixator should match the deformity prior to the osteotomy; this will allow accurate coronal and axial deformity correction.
4. Mark the patella, and maintain its position during the case.
5. LATN technique allowed gradual lengthening and correction of rotational deformity in the tibia.

Outcome clinical photos and radiographs:

• Figure 11: AP x-ray of right tibia. Patient had lengthening with the Taylor-Spatial frame and then insertion of IM nail (LATN).
• Figure 12: AP x-ray of right distal femur rotational and valgus correcting osteotomy
• Figure 13: AP x-ray of left distal femur rotational and valgus correcting osteotomy
• Figure 14: Final standing clinical photo. Note the restoration of mechanical axis alignment and limb length discrepancy.
• Figure 15: Final standing clinical photo. Patient ambulation much improved.
• Figure 16: Final standing sagittal alignment.

Avoiding and Managing Problems

1. In complex rotational deformities, the physical exam is critical to accurately assess the deformity. Asking patients to ambulate, disrobed from the waist down will elucidate rotational, and dynamic deformities that cannot be otherwise assessed with static imaging.
2. A staged-approach is best with combined limb-length discrepancies and rotational deformities. A new 51’’ hip to ankle x-ray after stage one allows for modification, if necessary, of original planned procedures.

References

1. Pulisetti TD, Onwochei MO, Ebraheim NA, Humphries C, Coombs RJ. Mathematical precision in rotational corrective osteotomy of the femur. J Orthop Trauma. 1998;12:360-362.

2. Radler C, Kranzl A, Manner HM, Hoglinger M, Ganger R, Grill F. Torsional profile versus gait analysis: consistency between the anatomic torsion and the resulting gait pattern in patients with rotational malalignment of the lower extremity. Gait Posture. 2010;32:405-410.

3. Rozbruch SR. Fixator assisted plating of limb deformities. Operative Techniques in Orthopaedics. 2011;21:174-179.

4. Rozbruch SR, Kleinman D, Fragomen AT, Ilizarov S. Limb lengthening and then insertion of an intramedullary nail: a case-matched comparison. Clin Orthop Relat Res. 2008;466:2923-2932.

5. Seah KT, Shafi R, Fragomen AT, Rozbruch SR. Distal femoral osteotomy: is internal fixation better than external? Clin Orthop Relat Res. 2011;469:2003-2011.

Authors