In a retrospective study, 100 patients underwent a clinical and radiological follow-up examination after a minimum of 7 years (range 7.0-9.3 years) following an arthroscopic partial medial meniscectomy. None of these patients had associated intra-articular lesions, apart from minor chondral damage (max. grade 2 Outerbridge classification; < 1 cm2) of the medial compartment at the time of the primary arthroscopy. According to the modified Marshall score, the follow-up evaluation showed excellent clinical results in 96%. Nevertheless, the radiological outcome, as measured by comparing preoperative and postoperative X-rays, demonstrated a development or progression of the osteoarthritis of the affected knee joint in 33%, with a statistically significant correlation between the radiological and clinical outcomes (P < 0.05). The age of the patients at the time of operation and any angular deformity of the knee joint did not influence the radiological results. Women had a statistically significantly higher risk of developing gonarthrosis after partial medial meniscectomy than men (P < 0.05). The arthroscopic partial medial meniscectomy led to excellent subjective and functional results but could not prevent the increase or development of late degenerative changes in the medial knee compartment.