Arthroscopic treatment of popliteal cysts: clinical and magnetic resonance imaging results.
OBJECTIVE
This study examined the functional and magnetic resonance imaging (MRI) outcomes of popliteal cysts with combined intra-articular pathologies that were treated arthroscopically by decompression and a cystectomy through an additional posteromedial cystic portal.


METHODS
From January 2003 to March 2008, 31 patients were treated with a modified arthroscopic technique to decompress a popliteal cyst. The connecting valvular mechanism was found in all cases at the posteromedial compartment through the anterolateral viewing portal, and it was corrected by resecting the capsular fold through the posteromedial working portal. For cysts with multiple fibrous septa, an additional portal, the so-called posteromedial cystic portal, was used for complete cyst removal. The functional outcome was evaluated by use of the Rauschning and Lindgren knee score. All patients were evaluated by MRI, which documented the popliteal cyst and associated intra-articular lesions preoperatively and at follow-up.


RESULTS
All patients could return to their previous daily activities with few or no limitations, and no additional surgery was required after a mean follow-up of 36.1 months (range, 12 to 72 months). The Rauschning and Lindgren knee score showed improved clinical features at the final follow-up in 94% of patients. The follow-up MRI study showed that the cyst had disappeared in 17 knees (55%) and had reduced in size in 14 knees (45%) in the 31 patients. The mean cyst size was reduced significantly from 6.8 to 0.8 cm (P < .0001).


CONCLUSIONS
The described arthroscopic technique with or without an additional posteromedial cystic portal is effective for treating popliteal cysts with combined intra-articular lesions. More importantly, follow-up MRI showed that the cyst size was reduced or it had disappeared in all cases, although there was no association between the cyst's disappearance and the follow-up clinical score.


METHODS
Level IV, therapeutic case series.
Ahn
Jin Hwan
JH
Department of Orthopaedic Surgery, Sungkyunkwan University School of Medicine, Samsung Medical Center, Seoul, South Korea.
Lee
Sang Hak
SH
Yoo
Jae Chul
JC
Chang
Moon Jong
MJ
Park
Yong Serk
YS
D001182:Arthroscopy / Q000379:methods*; D019299:Decompression, Surgical / Q000379:methods; D005500:Follow-Up Studies; D006801:Humans; D007719:Knee Joint / Q000601:surgery; D008279:Magnetic Resonance Imaging / Q000379:methods*; D011151:Popliteal Cyst / Q000473:pathology* / Q000601:surgery*; D057234:Preoperative Period; D016896:Treatment Outcome