Sonographically Guided Posterior Cruciate Ligament Injections: Technique and Validation

Objective: To describe and validate a technique for sonographically guided posterior cruciate ligament (PCL) injections. Design: Prospective, cadaveric laboratory investigation. Setting: Procedural skills laboratory. Subjects: Eight unembalmed, cadaveric, mid-thigh-knee specimens (4 left knees and 4 right knees) obtained from 4 male and 4 female donors aged 57 to 64 years (mean 60.8 years) with body mass indices of 27.7 to 36.5 kg/m² (mean 32 kg/m²). Methods: A 5-2-MHz curvilinear probe and a 22-gauge, 78-mm stainless steel needle was used to inject 2 mL of diluted blue latex into the PCL of each specimen using an in-plane, caudad-to-cephalad approach. At a minimum of 24 hours postinjection, each specimen was dissected to assess the presence and distribution of latex within the PCL. Main Outcome: Presence and distribution of latex within the PCL. Results: All 8 injections accurately delivered latex throughout the PCL, including the tibial and femoral footprints. In 2 of 8 specimens (25%), a small amount of latex was noted to extend beyond the PCL and into the joint space. No specimens exhibited evidence of needle injury of latex infiltration with respect to the popliteal neurovascular bundle, menisci, hyaline cartilage, or anterior cruciate ligament. Conclusions: Sonographically guided intraligamentous PCL injections are technically feasible and can be performed with a high degree of accuracy. Sonographically guided PCL injections should be considered for research and clinical purposes to deliver therapeutic agents into the PCL postinjury or postreconstruction.