Is a unilateral partial osteotomy high tibial osteotomy with bone graft indicated for a patient with a left Medial Proximal Tibial Angle (MPTA) of 85 degrees and a Lateral Distal Femoral Angle (LDFA) of 93.7 degrees?

High Tibial Osteotomy for Varus Knee Malalignment

A unilateral partial ostectomy high tibial osteotomy with bone graft is indicated for this patient with a left MPTA of 85 degrees and LDFA of 93.7 degrees, as these measurements confirm varus malalignment requiring surgical correction. 1

Biomechanical Assessment

The patient's measurements indicate significant varus malalignment:

• MPTA (Medial Proximal Tibial Angle) of 85° (normal is approximately 87-90°)
• LDFA (Lateral Distal Femoral Angle) of 93.7° (normal is approximately 87-90°)

These values confirm a varus knee deformity primarily originating from the proximal tibia, making high tibial osteotomy an appropriate surgical intervention.

Surgical Indication

High tibial osteotomy is indicated based on the following criteria:

• Unicompartmental knee malalignment (varus deformity)
• Mechanical axis deviation requiring correction
• Potential to preserve the native knee joint

The AAOS guidelines specifically state that "realignment osteotomy is an option in active patients with symptomatic unicompartmental OA of the knee with malalignment" (Grade C recommendation) 1. The procedure aims to shift the mechanical axis laterally to unload the medial compartment.

Surgical Technique

For this patient, a medial opening-wedge high tibial osteotomy is recommended:

1. Approach: Medial approach to avoid lateral muscle detachment and peroneal nerve injury
2. Osteotomy type: Biplanar opening-wedge osteotomy for improved rotational stability
3. Correction goal: Increase MPTA from 85° to approximately 90-92° to achieve neutral to slight valgus alignment
4. Bone graft: Autogenous bone graft to fill the opening wedge
5. Fixation: Rigid fixation with a medial plate-fixator to allow early mobilization and prevent loss of correction 2

Benefits of This Approach

• Preserves joint function while correcting alignment
• Avoids complete joint replacement
• Allows for precise correction that can be adapted intraoperatively
• Maintains bone stock for potential future procedures
• Provides better long-term outcomes compared to arthroscopic procedures alone 1

Expected Outcomes

With proper technique and patient selection, high tibial osteotomy provides:

• Pain relief
• Functional improvement
• High rate of return to activities
• Survivorship ranging from 74.7% to 97.6% at 10 years 3

Potential Complications and Mitigation

• Loss of correction: Prevented by rigid fixation with medial plate-fixator
• Delayed healing: Can be addressed with secondary bone grafting if needed
• Joint stiffness: Early mobilization is essential
• Hardware irritation: May require removal after healing

Postoperative Management

• Regular clinical and functional assessments
• Radiographic evaluation at 12 months post-surgery (or earlier if concerns arise)
• Continued assessment until skeletal maturity 1
• Physical therapy to maintain range of motion and strength

Conclusion of Recommendation

The patient's angular measurements (MPTA 85° and LDFA 93.7°) clearly indicate a varus malalignment that would benefit from correction through high tibial osteotomy. The procedure should be performed using a medial opening-wedge technique with bone grafting and rigid fixation to achieve optimal correction and stability.