What did the study look at?
Although most patients have long-term stability after ACL reconstruction, the authors report that about 1.8% to 10.4% need a revision (repeat operation). If the old tunnels have widened, or are positioned where they would collide with the new ones, a two-stage approach may be considered: first the tunnels are filled with bone, then the ligament is reconstructed again. The aim of the article is to describe a technique for this first stage using cannulated allograft (donor) bone dowels soaked in bone marrow aspirate concentrate (BMAC).
How was it done?
This is not a patient study but a video-supported surgical technique note. The main steps described are:
- Before surgery, the diameter and position of the tunnels are assessed with X-rays and, if needed, computed tomography. According to the authors, a two-stage revision should be considered if the old tunnels may interfere with the new ones or if tunnel widening exceeds 12 mm.
- After arthroscopy, the old screws and other fixation hardware are removed.
- The shin bone tunnel is re-reamed to 12 mm and the thigh bone tunnel to 10 mm, creating regular, cylindrical tunnels.
- About 60-100 mL of bone marrow is taken from the front of the pelvic bone, centrifuged for about 20 minutes, and the dowels are soaked in the resulting concentrate.
- The dowels are placed in the tunnels over a guide pin and delivery sleeve, their protruding edges are trimmed, and the lower part of the shin tunnel is packed with minced allograft bone.
What did it find?
The article does not report measured patient outcomes. The advantages listed by the authors are: avoiding the problems of harvesting the patient's own bone; turning irregular tunnels into measurable ones by reaming; shorter operating time thanks to pre-sized dowels; a guide pin that keeps the dowel from slipping into the joint; and immediate structural support of the bony void.
After surgery, weight bearing as tolerated with crutches and a brace for the first 2 weeks is advised, avoiding high-load exercises. The second stage can be done once the grafted tunnels show adequate healing on X-ray, usually at about 4 to 6 months.
The authors' conclusion
The authors describe the technique as a safe and reliable method to support graft-to-bone healing and more accurate anatomic tunnel placement at revision. They emphasise, however, that further studies are needed to describe the long-term patient outcomes of the technique.
Limitations
The authors note that allograft bone may have a lower healing capacity than the patient's own bone, and that because commercially available dowels are at most 18 mm in diameter, their use may be limited in larger defects.
Reference
Fortier LM, Gürsoy S, Singh H, Chahla J. (2021). Two-Stage Revision Anterior Cruciate Ligament Reconstruction with Cannulated Allograft Bone Dowels Soaked in Bone Marrow Aspirate Concentrate. Arthroscopy Techniques, 10(12), e2699. Licence: CC BY-NC-ND 4.0.
DOI: 10.1016/j.eats.2021.08.013
Free full text: PMC8719137
This article summarises a published scientific paper for general information; it does not replace an examination or a personal medical assessment. Please consult your doctor about your symptoms.
