Arthroscopic Treatment of Popliteal Cyst: A Direct Posterior Portal by Inside-Out Technique for Intracystic Debridement

Abstract

Popliteal cysts are characterized by enlargement of the gastrocnemius-semimembranosus bursa. The pathogenesis includes a valvular opening between the knee joint and the bursa, and associated intra-articular pathology may give rise to knee effusion. The mainstay of treatment is conservative. If popliteal cysts are symptomatic, analgesia, aspiration, and steroid injection therapy may be considered, but most recur rapidly. In the past, open excision was an option if they remained symptomatic, but the associated recurrence rate was high. One important reason was that the intraarticular pathology causing the knee effusion was not treated. We present an alternative minimally invasive arthroscopic treatment using dye (methylene blue) directly injected into the cyst, which will leak from the cyst into the joint, to identify the valvular opening. The thickened valve is opened using a basket forceps and then enlarged using a motorized shaver to disrupt the 1-way mechanism between the joint and bursa, as well as to establish an unobstructed freeway connection between them. We also present a safe technique to create a direct posterior portal. Intracystic debridement of the fibrous membrane, nodules, and septa through this portal will decrease the recurrence rate of the popliteal cyst. P opliteal cysts (also termed "Baker cysts") were first described over a century ago by Adams 1 and later by Baker.2 They are most frequently characterized by enlargement of the gastrocnemius-semimembranosus bursa, which is one of several bursae around the knee. Studies of the pathogenesis of popliteal cysts have shown that they are connected to the knee joint by means of a valvular opening.3,4 The presence of a valve, along with the existence of an effusion, creates unidirectional flow of the synovial fluid from the articular cavity to the cyst and is one of the fundamental factors responsible for the appearance and persistence of the cyst.Treatments for popliteal cysts have included conservative approaches or open resection. [5][6][7] Because the cysts are often asymptomatic and resolve spontaneously, many are treated by observation alone. If they are symptomatic, analgesia, aspiration, and steroid injection therapy may be considered, but most recur rapidly. In the past, open excision was an option if they remained symptomatic; however, an associated recurrence rate as high as 42% to 63% has been reported. 6,7 Several studies have reported frequently associated intra-articular pathologies with the cysts and warned of a high recurrence rate if the intra-articular pathologic condition is not addressed. 8-12Arthroscopic intervention is favored over open excision because of the successful outcomes of arthroscopic treatment for conditions associated with popliteal cysts. Arthroscopy is minimally invasive, is associated with a lower amount of risk, directly addresses both intraarticular pathology and the cyst, and allows early aggressive rehabilitation. Recent advances in arthroscopic techniques have been made to effectively address the ...

Treatment of baker cyst, by using open posterior cystectomy and supine arthroscopy on recalcitrant cases (103 knees)

“…Kongmalai et al [ 45 ] described the use of a direct arthroscopic posterior portal in addition to a posteromedial portal for overcoming difficulties in intracystic debridement of cysts with septation.…”

Arthroscopic Treatment of Popliteal Cysts with and without Cystectomy: A Systematic Review and Meta-Analysis

“…Recent advances in arthroscopic techniques make it possible to effectively address the intra-articular pathology, particularly the orifice of the cyst and the cyst itself, which has a valvular mechanism 15) . Resecting the inner wall and septa inside the cyst while correcting the valvular mechanism has produced excellent results in previous papers 6 , 16 – 19) .…”

Arthroscopic patterns of the poster-medial aspect of the knee joint: classification of the gastrocnemius-semimembranosus gateway and its relationship with Baker’s cyst

“…Several surgical approaches are available; the most of the Authors sustains the importance of treating intrarticular disease which, probably, causes the onset of the cyst. Our group and other surgeons prefer also to close the gateway 6,38,39 , otherwise other Authors suggest to enlarge the communication, removing the valve mechanism [40][41][42][43] . A recent review analyzed 11 studies valuing the results of the surgical approach; it evidenced a success rate of 96.7 and 84.6% in the communication-enlargement group and communication-closure group, respectively; considering just the first group, the percentage of success was 98.2% for the Authors sustaining resection of the cyst wall and 94.7% for the Authors which don't do it 44 .…”