Midterm outcomes of 18 patients with primary intra-articular diffuse tenosynovial giant cell tumor (TGCT) of the knee treated with complete arthroscopic synovectomy and postoperative low-dose radiotherapy at a mean follow-up of 68 months.

OBJECTIVE: To evaluate the long-term clinical outcome of the treatment of complete arthroscopic synovectomy combined with low-dose external radiotherapy in the knee affected by primary intra-articular diffuse tenosynovial giant cell tumor (TGCT).

METHODS: From May 2009 to January 2016, 18 patients with intra-articular diffuse TGCT underwent complete arthroscopic synovectomy and low-dose external-beam radiotherapy in Zhongnan Hospital were enrolled in this retrospective study. The preoperative symptoms of patients, the complications during or after the arthroscopic procedure and the recurrence were collected and recorded. Each patient was evaluated before treatment and at the follow-up visit. Efficacy evaluation criteria were based on Ogilvie-Harris score, and the evaluation of the functional ability of knee was based on the International Knee Documentation Committee (IKDC) Score.

RESULTS: The mean time from symptom onset to surgery was 9.1 ± 5.8 months (range from 3 to 29 months). The most frequent preoperative symptoms were joint effusion (100%), diffuse non-specific knee pain (66.7%), and a decreased range of motion (83.3%). Mean follow-up time was 68.0 ± 18.1 months (range from 35 to 120 months). The mean evaluation score according to the Ogilvie-Harris criteria before treatment was 3.19 ± 0.74, which corresponded to a rating of "poor". The mean score after treatment was 8.79 ± 1.57, rated as "good". The Ogilvie-Harris score was significantly increased after treatment (P = 0.003). The IKDC score of all patients increased significantly from 37.1 ± 3.8 before treatment to 83.9 ± 11.3 after treatment. The IKDC score was obviously increased after treatment (P = 0.001). No recurrence was noted at final follow-up. There were no complications during or after the arthroscopic procedure.

CONCLUSION: The outcome of this study proved that complete arthroscopic synovectomy combined with low-dose external radiotherapy was appropriate for treating primary intra-articular diffuse TGCT of the knee joint. It could be safely and reliably used with minimal complications, fast postoperative recovery and satisfactory control of recurrence rates.