Tibial deflexion osteotomy (anterior closing wedge, slope-reducing)

Rationale

• A steep posterior slope shifts the tibia anteriorly at rest and increases anterior tibial translation under load, which stresses the ACL graft.
• PTS greater than 12 degrees is a recognised risk factor for ACL graft failure. - Miller's Review of Orthopaedics 9th Edition, p. 362
• Campbell's also notes that increased PTS is a possible risk factor for ACL injury in both sexes. - Campbell's Operative Orthopaedics 15th Ed 2026
• The reverse also applies. A reduced slope is linked to PCL injury and to residual posterior tibial translation after PCL reconstruction. - Campbell's Operative Orthopaedics 15th Ed 2026

Indications

• Revision ACL reconstruction (especially second or later revisions) with PTS of 12 degrees or more.
• Primary ACL reconstruction with very high PTS plus other risk factors, such as a young pivoting athlete or high-grade pivot shift. This is a judgment call with less evidence.
• Recurrent anterior instability with a documented sagittal deformity.

Cautions and contraindications (from general technique literature, not the textbooks above)

• Baseline knee hyperextension or recurvatum, because correction can worsen it.
• PCL insufficiency, because lowering the slope increases the risk of posterior sag.
• Patella baja or altered patellar height. Miller's says the osteotomy level relative to the tibial tubercle must account for patellar height and baseline hyperextension. - Miller's Review of Orthopaedics 9th Edition, p. 362
• Advanced osteoarthritis or poor bone or soft-tissue quality.

Technique outline

1. Planning: Measure PTS on a true lateral radiograph or MRI. Plan the wedge size from the target slope, usually about 5 to 7 degrees postoperatively. Check patellar height, hyperextension, and coronal alignment on long-leg films.
2. Approach: Anteromedial or midline exposure of the proximal tibia. Protect the patellar tendon.
3. Osteotomy: Place an anterior-based wedge, with the cut level chosen relative to the tubercle. Techniques vary: supratubercle, infratubercle, and with or without tubercle osteotomy. Keep a posterior hinge intact.
4. Closure and fixation: Close the wedge by extending the knee. Fix with plates, staples, or screws. Fixation strategies differ between authors.
5. ACL reconstruction: Done concurrently (most common) or staged. Tunnel placement and fixation need to account for the altered tibial geometry.
6. Rehabilitation: Protected weight bearing until the osteotomy heals, early extension, and graded return to sport. Exact protocols vary by surgeon.

Outcomes

• Mean PTS fell from 15.2 to 7.1 degrees.
• Recurrent graft failure occurred in 3 of 133 knees (2.25%).
• IKDC rose from 42.5 to 71.8, Lysholm from 46.4 to 89.0, and Tegner from 4.2 to 6.7.
• About half the knees were second or later revisions.

Recent evidence check (last 2 years)

• PMID 39536996: slope-reducing osteotomy improves outcomes in ACL reconstruction patients with elevated PTS, especially revisions and PTS of 12 or more.
• PMID 40286998: the commonest indication is graft failure with PTS of 12 or more.

Recent studies on tibial deflexion (slope-reducing) osteotomy

Systematic reviews

• Tollefson et al. 2025, Arthroscopy PMID 39536996
  • It included 16 studies. Posterior tibial slope (PTS) fell significantly in nearly all of them, and patient-reported outcomes (PROs) and anterior tibial translation improved.
  • The authors found that ACL reconstruction failure rates decreased. They recommend considering osteotomy when PTS is 12 degrees or more, especially after a failed ACL reconstruction.
  • The commonest complications were postoperative hyperextension and hardware irritation. Hardware irritation was reported only when plates were used.
  • The studies were too heterogeneous for pooled statistics.
• Vivekanantha et al. 2025, Arthroscopy PMID 40286998
  • The commonest indication was graft failure with PTS of 12 degrees or more. I only saw the title and indexing for this paper, not the full abstract.
• Moran et al. 2024, J ISAKOS PMID 38945397
  • It included 6 case series with 133 knees. PTS fell from 15.2 to 7.1 degrees.
  • Recurrent graft failure was 2.25%. The IKDC score rose from 42.5 to 71.8 and the Lysholm score from 46.4 to 89.0.

Primary studies

• Wang et al. 2025, Am J Sports Med PMID 40230218
  • This was the first comparative data in primary ACL reconstruction: a propensity-matched case series (Level IV) of 25 osteotomy knees versus 48 isolated reconstructions. Patients had PTS of 15 degrees or more and anterior subluxation of the lateral compartment of 6 mm or more. Minimum follow-up was 2 years.
  • PTS fell from 18.2 to 6.7 degrees.
  • Graft laxity at 2 years was 12.0% with osteotomy versus 35.4% without (P = .033).
  • Graft failure did not differ significantly (8.0% vs 12.5%).
  • Second-look arthroscopy showed less graft roof impingement with osteotomy (4.0% vs 22.9%).
  • In stratified analysis, failure rate and KT-1000 side-to-side difference improved significantly in the subgroup with PTS of 16 degrees or more.
• Piercecchi et al. 2025, OTSR PMID 41197711
  • This was a retrospective series of 46 revision ACL reconstructions with infratubercle osteotomy fixed with a locking plate, with PTS of 12 degrees or more. The mean correction was about 9 degrees.
  • Coronal alignment was preserved and all osteotomies healed within 4 months.
  • There was one superficial infection and one screw backout. There were no nonunions or hinge fractures. These are short-term radiographic results only.
• Helm et al. 2025, Orthop J Sports Med PMID 40756375
  • This was a 3D simulation in 11 tibias.
  • All simulated osteotomies added varus. The effect grew with larger corrections, and corrections of 9 degrees or more increased varus in every osteotomy.
  • It was largest with an AP mid-axis start point in transtubercle and infratubercle osteotomies, up to about 1.8 degrees of added varus.
  • A tubercle-referenced start point minimized the coronal change.
• Kim et al. 2025, OTSR PMID 39197639: Title only, which states that lower starting points imply larger bone resection.

Technique and planning papers (2024 to 2026)

• Single-stage primary ACL reconstruction with slope-reducing osteotomy and lateral extra-articular tenodesis: PMID 40936544.
• Infratubercle technique descriptions: PMID 41425361 and PMID 39989682.
• Staple fixation with all-inside ACL reconstruction: PMID 40207342.
• How to measure PTS for planning: PMID 42383014.
• Review of indications, technique and outcomes: Guarino et al. 2026, Clin Sports Med.
• A narrative review in revision ACL reconstruction (PMID 41948254) and a bibliometric analysis (PMID 42944805).

Expert commentary

• Dejour et al. 2025 (PMID 40081626) argue for considering osteotomy in primary ACL reconstruction when PTS exceeds 12 to 14 degrees.
• Choi 2026 (PMID 42949191) suggests it for PTS above 12 degrees plus anterior tibial translation above 5 mm.
• Servant 2024 (PMID 38219118) notes that different osteotomy levels carry different risks.
• A reference list in a 2026 JASSM review cites Dan et al. (Arthroscopy 2024) as proposing a post-osteotomy target PTS of 4 to 6 degrees, guided by static anterior tibial translation. I did not read the original, so verify the target slope.

Take-home

1. Consensus is converging on PTS of 12 degrees or more with revision or recurrent failure as the clearest indication. The indication in primary ACL reconstruction is evolving, with thresholds of about 12 to 16 degrees plus excess anterior tibial translation.
2. There is no randomized trial yet. All outcome data come from retrospective series, so selection bias is likely.
3. Open questions are tubercle-referenced levels (supra-, trans-, infratubercle), unintended added varus with larger corrections, hyperextension, hardware irritation, and the right target slope.