Understanding the natural history of the post-meniscectomy knee and having an appreciation for factors that influence surgical outcome enable the surgeon to individualize patient treatment and optimize results. This article reviews the various biomechanical changes in the knee after meniscectomy. There is a resultant increase in tibiofemoral contact forces proportional to the amount of tissue removed, and an alteration in knee kinematics. Clinical studies that characterized the results after meniscectomy in terms of patient functional outcome and radiographic changes are also reviewed. Several studies have demonstrated that results after meniscectomy are negatively influenced by pre-existing osteoarthritis, chondral damage, anterior cruciate ligament deficiency or other significant ligament injury, extent and location of meniscectomy (lateral vs. medial), type of meniscal tear (degenerative vs. traumatic), and knee malalignment. However, there is no definitive correlation between gender and age and surgical outcome after partial meniscectomy, provided that the knee has no other concomitant pathology.