Limb Lengthening Academic Case Presentation
This case illustrates an approach to a young patient with a large varus deformity and LCL laxity. After analyzing the deformity, it became clear that the varus was coming from distal femur, proximal tibia, and joint line obliquity. Also present was a procurvatum deformity of the proximal tibia. We performed an acute deformity correction of the femur with a plate and a gradual correction of the tibia varus and procurvatum with a TSF. With correction of deformity, the LCL laxity improved dramatically.
Brief Clinical History:
32 year old male who complains of bilateral knee pain, left is worse than right and is unstable. Two years earlier, he underwent a high tibial osteotomy and MCL and PCL reconstructions. He feels persistent pain and instability.
Preoperative Clinical Photos:
- Figure 1, 2: Left MAD = 71 mm medial; LDFA = 92 deg.; MPTA = 84 deg.; Joint line convergence (JLCA) = 13 deg. varus; Right MAD = 30 mm medial; LDFA = 91 deg.; MPTA = 85 deg.; JLCA = 3 deg. varus. LLD = 1 inch left side short.
- Figure 3: LCL laxity and varus deformity (left)
- Figure 4: PPTA = 58 deg. (left tibia flexion deformity)
- Figure 5: Front view showing varus and LLD
Preoperative Problem List
- Left femur varus
- Left tibia varus and procurvatum deformity
- Left LCL laxity with JLCA 13 deg.
- Right leg varus deformity (moderate)
- Left sided deformity is a composite of 17 deg. varus from femur, tibia, and joint line obliquity. Plan is to correct femur varus by 7 deg. with closing wedge osteotomy and plate fixation. Correct tibia gradually with hexapod frame. Correct varus by 6 deg. to start and dial in correction to achieve an MAD of 0 or some overcorrection laterally. Correct tibia apex anterior deformity by 15 deg. and add length.
- Staged treatment of the right tibia varus. The deformity is predominantly coming from the tibia although the femur and joint line obliquity also contribute.
- Correction of femur with acute correction and internal fixation is safe and simpler than external fixation.
- Gradual correction of tibia allows one to address varus, apex anterior deformity, and shortening simultaneously in a safe manner.
- Gradual correction with the hexapod frame allows one to dial in the MAD correction. The joint line obliquity will change as the MAD is lateralized and the LCL laxity will decrease.
- LCL reconstruction may not be necessary after realignment.
Images During Treatment:
- Figure 6: Correction of MAD
- Figure 7: correction of apex anterior deformity
- Figure 8: Front view showing left realignment with hexapod frame.
- Figures 9, 10: Staged Correction of the right tibia
- Left femur closing wedge osteotomy is best done by leaving medial cortex intact and using a locked plate. The plate may sit off the bone without compromise to stability. A micro sagittal saw cooled with saline is used to perform the osteotomy.
- Correction of left tibia varus and flexion and shortening can be done effectively with hexapod frame. A multiple drill hole osteotomy is used.
Outcome clinical photos and radiographs:
- Figure 11: Slight overcorrection of MAD achieved. Note the correction of the joint line obliquity and LLD.
- Figure 12: Femur plate sits off the bone for best fit. Joint line obliquity improved.
- Figure 13: PPTA is normalized.
- Figures 14-15: Right side is healed in excellent position.
- Figure 16: Front view showing excellent realignment.
- Figure 17: Side view showing full knee extension on left.
- Figure 18: Back view showing excellent correction of deformity and LLD.
Avoiding and Managing Problems
- Try to make osteotomy through new bone. The left proximal osteotomy was made distal to the previous osteotomy to avoid delayed bone healing.
- Avoid over or under-correction of the MAD on left side by gradually correcting the tibia and dialing in the correction. The correction of the joint line obliquity is somewhat unpredictable. This is the “See-Saw Effect”.
References and Suggested Reading
Ashfaq K, Fragomen AT, Nguyen JT, Rozbruch SR: Correction of proximal Tibia Varus with External Fixation. J Knee Surgery 2012, 25(5):375-384.
Rozbruch SR, Segal K, Ilizarov S, Fragomen AT, Ilizarov G: Does the Taylor Spatial Frame Accurately Correct Tibial Deformities? Clin Orthop Rel Res 2010 May :468(5): 1352-61
Seah KT, Shafi R, Fragomen AT, Rozbruch SR: Distal Femoral Osteotomy: Is Internal Fixation Better than External? Clin Orthop Rel Res. 2011, 469: 2003-2011