Ultrasonographic assessment of pes anserinus tendon and pes anserinus tendinitis bursitis syndrome in patients with knee osteoarthritis.

Objective: The aim of this study was to assess the ultrasonographic (US) findings of pes anserinus tendon and bursa in patients with knee osteoarthritis (OA) with or without clinical pes anserinus tendinitis bursitis syndrome (PATBS).
Methods: A total of 157 female patients with the diagnosis of knee OA on both knees (314 knees), and 30 age, and body mass index- matched healthy female controls without knee pain (60 knees), were included in the study. PATBS was clinically diagnosed. US evaluation parameters were the measurement of the thickness of pes anserinus tendon insertion region (PA) and examination of the morphologic intratendinous PA tissue characteristics and pes anserinus bursitis (PAB). Radiographic knee osteoarthritis graded I-IV according to Kellgren and Lawrence (KL) for each knee was recorded. Pain and functional status were assessed by the Visual Analog Scale (VAS) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC).
Results: There were 183 PATBS (58.3%) clinical diagnoses among the 314 knees with OA. The mean thickness of PA in the patients with knee OA graded 1,2,3,4 with/without PATBS was significantly greater than the controls (p = 0.001). The mean thickness of PA in knees with OA KL graded 3 and 4 with/without PATBS, was greater than knees with OA KL graded 1 and 2 with/without PATBS (p < 0,05) (except knee OA KL graded 2 with PATBS versus knee OA KL graded 4 without PATBS).The knee OA KL graded 1,2,3,4 with PATBS had significantly more PAB and less loss of normal fibrillar echotexture of PA compared to controls and knees with OA KL graded 1,2,3,4 without PATBS (p < 0.05). The VAS scores of knees with OA KL graded 3, 4 with PATBS were significantly greater than those of knees with OA KL graded 3,4 without PATBS (p < 0.05). PA thickness was significantly associated with the KL grade (r: 0.336, p:0.001) and PATBS (r: 0.371, p < 0.001).
Conclusion: It is concluded that the mean thickness of PA in knees with OA with/without PATBS was significantly greater than the controls. The mean thickness of PA in knees with OA, KL graded 3 and 4 with/without PATBS, was greater than in knees with OA KL graded 1 and 2 with/without PATBS. The knee OA with PATBS had significantly more PAB, less loss of normal fibrillar echotexture of PA, and higher VAS scores compared to the knees with OA without PATBS. US can serve as a useful diagnostic tool for detection of PATBS in knee OA.