- if a "two incision - backdoor" technique is used, it is usually not necessary to measure graft length;
- whether the graft is slightly long or slightly short, it is usually very easy to move the graft slightly proximally or distally (through both tunnels) so that optimal interference screw fixation is possible for both ends of the graft;
- if a "one incision - transtibial" technique is used, careful consideration needs to be given to the graft length;
- if the graft is too long, the tibial plug will protrude from the tunnel and if the graft is too short, the graft will be buried deep in the tunnel (and in both cases, fixation w/ a interference screw may not be possible);
- the femoral bone plug measures 25 mm and the intra-articular graft length typically measures 25 mm;
- hence the required tibial tunnel length = (Total Graft Length - 50 mm);
- using the Arthrex Transtibial Guide System, use a 60 deg angle for graft lengths less than 100 mm (less than 50 mm tibial tunnel) and alternatively use the 70 deg angle for grafts greater than 100 mm (more than 50 mm tibial tunnel length);
- ensure that the guide pin sleeve is set to the appropriate tibial tunnel length
- 25-year-old who underwent a standard transtibial BPB ACL reconstruction;
- the graft was slightly short, and the tibial bone plug ended up in the middle of the tibial tunnel.
- the main problem with this is that the interferance screw might either be placed too distally or too proximally (the later might cause the patellar tendon to be cut by the screw threads).
- as a solution the surgeon tied the tibial tunnel over a post.
- 20-year-old male who underwent BPB ACL reconstruction which ultimately failed.
- on radiographs it is noted that the tibial tunnel is relatively posteriorly and it can be seen that the femoral bone plug was left about 5 mm extruded out of the femoral tunnel;
- 30-year-old male who presented for revision ACL reconstruction;
- (his medical history and operative note were not available for review);
- the obvious teaching points here are that both the femoral and tibial tunnels were placed far to anterior
