A Rare Cause of Knee Joint Stiffness
A 22-year-old woman came to us with a 2-week history of recurring stiffness of the left knee joint. MRI of the knee revealed a tumor arising from the Hoffa fat pad. The cause was a proliferative disorder of the synovial membrane (pigmented villonodular synovialitis, PVNS). Arthroscopy demonstrated the tumor sited in the notch; otherwise, the knee was normal for age. The Figure shows the excised tissue, measuring 3.5 × 2.5 × 1.8 cm. The specimen was arthroscopically removed in toto via a third port at the superior recess, using a curved forceps. Samples of synovial membrane showed no evidence of involvement. This indicates the presence of the solitary form of PVNS, which is less common than the diffuse form. In nodular PVNS tumor resection (open or arthroscopic) is the treatment of choice. The risk of recurrence of nodular PVNS is very low, 0 to 15%, but annual MRI should be carried out during the first few years of follow-up.
PD Dr. med. Matthias Lahner, Dr. med. Kamiar Fartash, Gelenkzentrum Hilden, email@example.com
Prof. Dr. med. Arne Streitbürger, Abteilung für Tumororthopädie und Sarkomchirurgie, Universitätsklinikum Essen
Conflict of interest statement: The authors declare that no conflict of interest exists.
Translated from the original German by David Roseveare.
Cite this as: Lahner M, Fartash K, Streitbürger A: A rare cause of knee joint stiffness. Dtsch Arztebl Int 2020; 117: 792. DOI: 10.3238/arztebl.2020.0792a