PVNS is a benign tumor that originates from the synovial tissue of the joint, the soft tissue lining the tendons and the bursa (a fluid filled saclike bodily cavity between the tendons and bones that ensures smooth motion). This benign synovial tumor becomes pigmented when haemosiderin from the blood gets deposited within it. It is found mostly in the knee and hip, but has been less commonly identified in most other joints, and affects either sex, mainly between the ages of 20 and 45.

PVNS is locally aggressive, and may spread to erode adjacent bone and tissue structures, sometimes reaching out of the confines of the joint capsule, if it is not treated early. It is sometimes known to grow into the adjacent bone structures themselves by following the vascular (blood vessel) channels of the bone. However, on average, the disease is not identified correctly until about 4 and a half years after presentation, as it is similar to many other joint conditions such as inflammatory arthritis or ligament instability, and is much more subtly detectable.  Early diagnosis of the disease requires meticulous examination of the radiographic imagery (x-ray, and MRIs) of the joint, of the symptoms, and is confirmed by biopsy. 

Symptoms can include stiffness and swelling of the joint due to extra fluid created by the synovial lining, a popping sensation when in motion, pain, tenderness, and a loss of range of motion: patients have a slightly decreased ability to flex and extend the joint. Normally, symptoms are monoarticualr (in one knee or one side of the hip) and start slowly, becoming sporadic in the later stages of PVNS. The tumor can occur in two severities: diffuse, affecting the entire synovium or nodular, only affecting a localized area.

Case Study: D.R. -  Diffuse PVNS Synovectomy and Total Knee Replacement

In April 2004, D.R. , a 66 year old athletic individual came to The Stone Clinic for a right knee evaluation. He had been diagnosed in 2001 with diffuse PVNS and underwent an arthroscopic synovectomy in 2002. Extensive meniscal and bone damage was observed and total knee replacement was recommended. He decided to continue his active lifestyle in hopes of avoiding total knee replacement. Yet, in 2004, his soreness increased significantly and he couldn’t ride the stationary bike for more than 20 minutes, or walk more than one-half mile. This is when he approached The Stone Clinic and Dr. Stone for further evaluation. His PVNS had recurred and become diffuse, eroding the surrounding meniscal and bone structures. He was in need of synovectomy, resection of tumor, neuroplasty and total knee replacement -- the whole package. The pigmented hyperplastic synovium was separated from the rest of the joint (Figure 1) and then completely removed (Figure 2). Extensive osteoarthritis was present (Figure 3), and total knee replacement was performed.

Figure 1: The pigmented hyperplastic synovium


Figure 2: The diffuse PVNS tumor after synoviym being separated from the knee joint


Figure 3: Osteoarthritis present after resection of tumor and synovectomy

He is now recovered, having a well placed knee replacement and no sign of PVNS recurrence.