Arthroscopic surgical approach and intra-articular anatomy of the equine suprapatellar pouch

Objective— To describe a direct arthroscopic approach to the suprapatellar pouch (SPP), its intra-articular anatomy, and report our clinical experience with SPP arthroscopy.
Study Design— (1) Experimental study and (2) retrospective clinical study.
Animals— (1) Cadaveric equine hind limbs (n=24; 14 horses) and (2) 5 horses.
Methods— Four femoropatellar joints (FPJ) were dissected or injected with latex to document surface landmarks and topographic anatomy. (1) Arthroscopic exploration of 20 SPP (10 equine cadavers) was performed and described, followed by dissection. (2) Medical records of horses that had FPJ arthroscopy were reviewed for cases where SPP portals were required.
Results— (1) The optimal arthroscopic portal was located ～10 cm lateral to the longitudinal patellar axis and 2 cm proximal to the patellar base in the intermuscular septum between the biceps femoris and vastus lateralis muscles. This approach allowed arthroscopic observation of the proximal aspect of the lateral and medial femoral trochlear ridges, the intertrochlear groove, the patellar base, and the synovial recess of the SPP. (2) Additional arthroscopic and instrument suprapatellar portals were used in 5 of 25 horses to complete lavage/debridement in osteochondritis dissecans (OCD) and septic arthritis.
Conclusion— Suprapatellar arthroscopy improved arthroscopic observation of structures located proximally in the FPJ and facilitated surgical access to the SPP.
Clinical Relevance— SPP arthroscopy is a safe and complementary approach to traditional distal FPJ arthroscopy that could be helpful for inspection and removal of free fragments/debris/fibrin located in the SPP, for OCD lesions extending proximally, and fracture(s) involving the proximal aspect of the patella.