Reachout Orthopedics - Issue 2

mass in most cases, they are also known to cause severe clinical problems such as pseudothrombophlebitis, thrombophlebitis, compartment syndrome, and neuropathy, most of which may need specific treatment such as surgical intervention [8–11]. A few previous reports have described the complicated popliteal cyst associated with RA [7, 12, 13]. However, since the underling pathophysiology of the disease itself and the particular pathology of popliteal cyst of RA might be quite different from that of OA, optimal surgical approaches and their technical aspect for good clinical outcome should be addressed. In this report, four patients with RA in combination with OA having refractory and complicated popliteal cysts who were successfully treated by means of arthroscopic treatment are described with a brief review of literatures of surgical management of popliteal cyst associated with RA. Methods This was a retrospective review of all cases with RA having refractory popliteal cysts that had been performed surgery during 2017–2018 at a single center in South Korea. We have reviewed the cases regarding demographic features, laboratory findings including autoantibodies such as rheumatoid factor (RF) and anti-citrullinated peptide antibody (ACPA), DAS 28-ESR (disease activity score 28-ESR), medications, radiographic findings including MRI, joint fluid analysis, number of intra-articular injection of glucocorticoid 6 months prior to surgery, and clinical outcomes after surgical treatment. The patients were informed that the data of the cases would be submitted for publication and provided their consent. This study was approved by the Institutional Ethics Review Board of Hanyang University Guri Hospital in South Korea. Search Strategy An electronic literature search was performed using the Medline, Embase, and Scopus databases. Articles written in English from 1960 to 2018 were searched. The following keywords were used along with the Boolean search function: “popliteal cyst” and “rheumatoid arthritis”. Because the scope of the literature review is limited to patients with RA who had been performed surgery for popliteal cyst, we carefully screened for appropriate studies. As a result, a total of nine reports (including one with only abstract available) were reviewed. Results A total of four patients were eligible for the current review. Table 1 summarizes details of the cases. The table includes initial clinical characteristics, autoantibodies such as RF and ACPA, DAS 28, medications, radiographic findings including MRI, and clinical outcomes after surgical treatment. All were females and seropositive (RF positive or ACPA positive). DAS28-ESR that are widely used for assessment of disease activity for RA was among 3.1–4.84, which means moderate disease activity except case 3 that showed low disease activity. All cases were combined with OA that represented by Kellgren– Lawrence grade (K–L grade) 2 or 3. Case 1 is described in detail below, which includes patient’s history and physical examination, radiography, MRI, surgical procedure, and arthroscopic and histologic findings. The remaining three cases are described briefly. Case 1 A 62-year-old woman with 15 years of history of seropositive RA presented with left knee joint discomfort and lower leg swelling. She was taking sulfasalazine 2 g/day, prednisolone 5 mg/day, and subcutaneous golimumab (anti-tumor necrosis factor monoclonal antibody). Intra-articular glucocorticoid injection was performed three times in the affected knee joint over a year, but without improvement. Her lower leg swelling had been aggravated for over 12 weeks, and she had suffered from increased pain with motion and limited knee flexion despite conservative treatment. Physical examination revealed cutaneous erythema, swelling, and tenderness of the left calf. She showed moderate disease activity of DAS28-ESR 4.84, erythrocyte sedimentation rate 110 mm/h, and C-reactive protein of 5.99 mg/dl. Radiologic imaging showed mild joint space narrowing without a significant valgus or varus deformity (K–L grade 2) (Fig. 1). Ultrasonography revealed popliteal cyst with synovial hypertrophy and analysis of joint fluid revealed white blood cell 17,200 with polymorphonuclear (PMN) cell 74%. MRI (fat-suppressed fast spin-echo T2-weighted images) revealed 4.1-cm multiloculated ganglion cysts at the popliteal fossa and a complicated popliteal cyst with leakage to the distal limb through a subcutaneous extension (Fig. 2). The distal leakage extended down to the mid-calf area. The patient was hospitalized to further evaluate the status and prevent further swelling of the lower limb. Fortunately, the patient did not develop severe complications such as compartment syndrome. Arthroscopy-assisted cyst decompression was planned. The operative procedure was conducted using three arthroscopic portals: the standard anterolateral, anteromedial, and the posteromedial portals. Using the posteromedial portal, the opening of the cyst was identified by inferiorly displacing the overlying capsular fold located at the posteromedial side of the medial head of the gastrocnemius. Once the opening had been identified, the capsular foldwas resected using basket forceps and an arthroscopic shaver. The valvular opening of the posterior capsule was enlarged to completely resect the capsular fold.The arthroscope was then switched to the posteromedial portal using a switching stick. The arthroscope was advanced further to the posterior and distal aspect which revealed the popliteal cyst consisted of debris and wall septa. The cystic wall was hypervascular and friable, which was different from the popliteal cyst wall in osteoarthritic knee joint (Fig. 3). Careful attention was given when debriding the lateral wall of the popliteal cyst to prevent damage to the adjacent neurovascular structures. Further debridement of the capsule was done down to the leakage area. A biopsy sample was taken from the cystic wall. Histopathological examination showed fibro- hyalinized tissue and plasma cells resulting from active chronic inflammation (Fig. 4). All procedures were performed with a standard 30° arthroscope. The water pump pressure was minimalized throughout the operation (not exceeding 50 mmHg) to prevent any further leakage through ruptured cyst which Popliteal cysts are usually seen secondary to osteoarthritis (OA), RA, and less commonly trauma, infections, and other causes of inflammatory arthritis. 24 reachOut Orthopedics