There are limited treatment options available for patients with mild to moderate medial knee osteoarthritis (OA) who are not yet candidates for or wish to avoid arthroplasty. The MISHA (medial implantable shock absorber) device addresses the gap in treatment options for this patient population who have failed non-operative treatment or have symptomatic medial OA despite prior surgical treatment and are not arthroplasty candidates. The MISHA procedure can be considered as a bridge treatment to allow restoration of mobility and activity while simultaneously delaying arthroplasty. Patients with medial compartment Kellgren-Lawrence grade 1-3 OA with relatively well persevered lateral and patellofemoral compartments who have load related medial knee symptoms, are active, and are motivated to avoid arthroplasty may be good candidates for this procedure. The MISHA device itself is comprised of a shock absorber which is affixed with locking screws through bases at the medial distal femur and proximal tibia. It is placed in an anisometric position by a simple intra-operative guide system and works by dissipating the pathologic joint loading during weight bearing. Importantly, in distinction to valgus producing osteotomy, the MISHA device offloads the medial compartment without shifting any load to the lateral compartment. Two and five-year results from a prospective trial comparing the MISHA procedure to high tibial osteotomy (HTO) have demonstrated a quicker recovery, better pain and function scores, as well as 99% two-year and 90% five-year survival free from conversion to arthroplasty ( 1 , 12 ) . Thus, the MISHA device provides a durable treatment option for medial OA which restores function and mobility and delays arthroplasty.
DeBruin et al. (Wed,) studied this question.