POPLITEAL CYSTS ASSOCIATED WITH UNDIAGNOSED POSTERIOI LESIONS OF THE MEDIAL MENISCUS*

This paper is particularly concerned with popliteal cysts, or bursae, accompanied i)y knee-joint effusionn, but without pathological conditions of the bones or joint de-monistrable by roenstgensograms. Although nearly all popliteal cysts communicate with the joinnt, it is gennerally agreed that results following surgical excision are unsiformly good, if recurrensce cans be prevented. Agreement is based on the assumption that the cyst., by inntermitt.ennt.ly discharging irritating fluid into the joint, produces a chronic synnovi t is. That. such optimism is uniwarransted is concluded from a study of twenty-one coni-sectntive excisions of the cyst durinsg the past seven years. There have beers no recur-rensees; yet the results were unsatisfactory in three patients. These patients had had previously unsdiagnsosed posterior lacerations of the medial meniscus, as proved by subse-(itnenit arthrotomies. Each recovered completely following meniscectomy. The mensiscal lesionns cannot be detected by x-rays or by air injections into the joint; and, in the presence of a cyst., the clinical signs are obscured. In a careful review of the literature, no mentions ni-as founsd of the association of this condition of the meniscus, diagnosed or undiagnosed