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PEARLS & PITFALLS – SURGICAL TECHNIQUE
Tips in ACL Revision Surgery
2. HAVE A PLAN
Surgical Technique to Use
For years, the transtibial technique has been the gold standard for ACL reconstruction. However, transtibial endoscopic ACL reconstruction often result in vertical graft orientation because of the inherent limitations in reaming an anatomic femoral and tibial tunnel. Non-anatomically positioned tunnels is one of the most common causes of clinical failure after ACL reconstruction with 15% to 31% of athletes complaining of pain, persistent instability, or an inability to return to the previous level of competition. For this reason, independent drilling of the tibial and femoral tunnels over the native ligament footprints is recommended.
For revision ACL reconstruction we normally favor single bundle anatomic technique but some surgeons advocate for a double-bundle reconstruction of the ACL. In a recent article Hofbauer, Fu F et al. showed a flowchart for surgical decision-making strategies according to previous femoral tunnel locations in revision surgery after failed primary double-bundle ACL reconstruction. Minimal mandatory requirements for secure double bundle technique remain; Tibial or Femoral ACL insertion site of more than 14 mm in diameter and notch width/height at least of 12 mm.
02
03
Type of Graft
Recent, systematic reviews on randomized prospective studies that compare hamstrings with BTB grafts have suggested that the type of graft is not the main determining factor for success in ACL reconstructions. Since most of the failures are a result of technical errors and not of graft choice, what counts is the surgeon’s experience with the technique used and the selection of the patient. The graft distribution in ACL reconstruction varies in different parts of the world but definitely Semitendinous-Gracillis (ST-G) graft has gained popularity within the last years. A US-based study reported 25% patellar tendon autografts, 31% hamstring autografts, 42% allografts, and 2% other grafts. Autografts were used for primary ACL reconstruction in 90% of the patients and allografts in 5% in a study from Ontario, Canada.
Results from a present large prospective study from Scandinavia using the Norwegian National Knee Ligament Registry (NKLR), based on 45.998 primary ACL showed that patients receiving patellar tendon autografts had a statistically significantly lower risk of revision compared with patients receiving hamstring autografts specially for those patients with higher demands. Interestingly, patellar tendon and hamstring autografts were used in 14.6% and 84.1% of the patients, respectively. The remaining patients received allografts, direct sutures, or other graft types (1.3%).
Table 4 Summarize the pros and cons in between ST-G and BTB autograft.
Table 4. Classical Differences Associated to the Use of BTB or ST-G Autografts.
Pros
Cons
BTB
• Fixation with osseous plug
• Greater revascularization capacity
• Less risk of failure
• Greater tensional
strength
• Better flexion
• Faster and more vigorous
return to sports
• Better Tegner Score
• Anterior knee pain
• Late arthritis, specially
patellofemoral
• Kneeling difficulty
• Knee flexion and
extension difficulty
• Less strength at
extension (first 6 months)
• Patellar tendon
shortening
• Paresthesia in medial
region
• Technically demanding
• Skeletal immature
patients
ST-G
• Ease Extension
• Less anterior knee pain • Less kneeling pain
• Reduction in flexion strength (first 6 months)
• Reduced stability
• Posterior knee pain
• LCA agonist muscles
weakening
• Bone-soft tissue fixation
• Tunnels widening
• Internal saphenous
neuromas
• Hematomas
• Higher revision rate than
BTB
14 ISAKOS NEWSLETTER 2015: Volume I