Is a high tibial osteotomy with bone graft indicated for a patient with a mild varus deformity, given a Lateral Distal Femoral Angle (L DFA) of 87 degrees and a Medial Proximal Tibial Angle (M PTA) of 86.5 degrees?

High Tibial Osteotomy for Mild Varus Deformity

High tibial osteotomy (HTO) with bone graft is not indicated for a patient with only mild varus deformity as shown by the measurements of L DFA 87° and M PTA 86.5°, as these values are very close to normal ranges (88-90°) and do not represent sufficient deformity to warrant surgical correction. 1

Analysis of Deformity Measurements

• The patient's measurements show:
  • Lateral Distal Femoral Angle (L DFA): 87° (normal range: 88-90°)
  • Medial Proximal Tibial Angle (M PTA): 86.5° (normal range: 88-90°)

These values represent only a mild deviation from normal anatomical alignment, with both measurements being just slightly below the normal range. This indicates a very mild varus deformity that does not meet typical surgical thresholds.

Evidence-Based Indications for HTO

Research indicates that HTO should be reserved for more significant deformities:

• A 2021 study found that even with moderate to severe varus alignment (mechanical tibiofemoral varus angle ≥3°), only 57% of patients would be appropriate candidates for isolated HTO if overcorrection of the medial proximal tibial angle was accepted 1
• For anatomic correction without excessive overcorrection, only 12% of patients with varus deformity would be appropriate for isolated HTO 1
• The patient's measurements show deviations of only 1-1.5° from normal range, which is considerably less than the deformities typically addressed with HTO

Surgical Decision-Making Considerations

When evaluating candidates for HTO, several factors should be considered:

1. Severity of deformity: The patient's deformity is minimal and likely doesn't contribute significantly to mechanical symptoms

2. Risk-benefit ratio: Surgical complications of HTO include:

   • Infection
   • Thrombophlebitis
   • Transient peroneal nerve palsy (reported in 9% of patients) 2
   • Delayed healing requiring secondary bone grafts 3

3. Alternative approaches: For mild deformities, non-surgical management should be prioritized before considering invasive procedures

Guidelines for Orthopedic Management

Current orthopedic guidelines suggest:

• Osteotomies should be performed at the site of major deformity and only when the deformity is significant enough to warrant surgical correction 4
• Delaying surgical treatment for residual deformity until skeletal maturity might be prudent due to notable rates of recurrence and complications 4
• Surgical treatment carries risks including a 57% complication rate in some studies, with recurrent deformity in 29% of patients 4

When HTO May Be Indicated

HTO would be more appropriate in cases with:

1. More significant varus deformity (typically mechanical femorotibial angle >4°) 5
2. Symptomatic osteoarthritis of the medial compartment 2
3. Documented progression of deformity despite conservative management
4. Functional limitations directly attributable to the deformity

Conclusion

The patient's mild varus deformity as indicated by L DFA 87° and M PTA 86.5° does not warrant high tibial osteotomy with bone graft. The minimal deviation from normal anatomical alignment suggests that the risks of surgical intervention would outweigh potential benefits. Non-surgical management should be considered as the first-line approach for this patient.