Clinical information
From March 2014 to July 2020, a total of 19 patients (6 males and 13 females) with diffuse PVNS of the knee were treated in our department, aged 6–78 years (average 39.8 years), and the course of the disease was 20 days − 10 years. This study have been performed in accordance with the Declaration of Helsinki and been approved by the ethics committees of Zhu Jiang Hospital of Southern Medical University ethically and provided the corresponding ethical certificate (NO. 2021-KY-165-03) and informed consent. All patients complained of varying degrees of knee joint swelling, pain, and dysfunction before surgery. A preoperative MRI examination was performed for the initial diagnosis of diffuse PVNS as shown in Fig. 2, then all cases were confirmed to be PVNS by postoperative pathology. The postoperative follow-up time was 1–6 years. Only 2 cases recurred. As shown in Table 1 below.
Table 1
Number | Age (years) | Duration of symptoms (months) | Treatment | Pre-op VAS score | Post-op VAS score | Pre-op TLS score | Post-op TLS score | pathology | Recurrence | Follow-up (months) |
1 | 20 | 5 | ATSP | 7 | 2 | 64 | 90 | PVNS | No | 72 |
2 | 38 | 48 | ATSP | 4 | 2 | 64 | 90 | PVNS | No | 70 |
3 | 36 | 1 | ATSP | 1 | 0 | 70 | 80 | PVNS | No | 69 |
4 | 78 | 120 | ATSP | 8 | 3 | 60 | 80 | PVNS | Yes | 67 |
5 | 45 | 108 | ATSP | 7 | 3 | 64 | 100 | PVNS | No | 57 |
6 | 30 | 6 | ATSP | 6 | 2 | 60 | 90 | PVNS | No | 62 |
7 | 49 | 12 | ATSP | 3 | 1 | 80 | 100 | PVNS | No | 39 |
8 | 50 | 4 | ATSP | 3 | 0 | 90 | 98 | PVNS | No | 39 |
9 | 8 | 10 | ATSP | 3 | 0 | 66 | 100 | PVNS | No | 31 |
10 | 6 | 48 | ATSP | 4 | 1 | 72 | 80 | PVNS | No | 31 |
11 | 27 | 6 | ATSP | 8 | 3 | 60 | 72 | PVNS | Yes | 25 |
12 | 58 | 24 | ATSP | 5 | 2 | 64 | 90 | PVNS | No | 25 |
13 | 64 | 5 | ATSP | 7 | 3 | 76 | 90 | PVNS | No | 25 |
14 | 67 | 24 | ATSP | 7 | 2 | 48 | 82 | PVNS | No | 23 |
15 | 52 | 6 | ATSP | 2 | 0 | 60 | 80 | PVNS | No | 22 |
16 | 16 | 2 | ATSP | 6 | 2 | 24 | 100 | PVNS | No | 21 |
17 | 50 | 12 | ATSP | 2 | 0 | 38 | 84 | PVNS | No | 16 |
18 | 41 | 24 | ATSP | 5 | 2 | 72 | 88 | PVNS | No | 12 |
19 | 23 | 12 | ATSP | 5 | 0 | 36 | 100 | PVNS | No | 13 |
Histological Staining
Synovial tissues were harvested and fixed with 4% paraformaldehyde for 2 h. They were subsequently dehydrated and embedded in paraffin. Paraffin sections were made to a thickness of 5 µm. Conventional HE staining was subsequently performed, and the stained sections were scanned using a multifunctional digital pathology scanner (Aperio VERSA 8). Subsequently, image information was acquired.
Main Equipment
The 4.0 mm, 30 ° angle arthroscopy, cold light source, camera imaging system and planing system produced by Shrek company of the United States (model 1488-010-0001). The plasma cold ablation instrument and the electric pneumatic tourniquet produced by Smith & nephew company of the United Kingdom.
Surgical Methods
The patient was placed in a supine position, and the combined spinal-epidural nerve block (intratracheal general anesthesia for children and patients unable to lumbar puncture), a pneumatic tourniquet on the upper-middle and upper thighs (200mmHg for children, 350mmHg for adults, 90min), and the normal saline with the specification of 3L/Bag was suspended at a height of about 1.5m from the operating table for joint cavity irrigation. The anterolateral approach of the patella is routinely used to examine the suprapatellar capsule, patellofemoral joint, medial groove, medial joint space, intercondylar fossa, lateral joint space, and lateral groove in turn to understand the distribution and proliferation of synovium, as well as ligaments, and semilunar involvement of the plate. After the exploration, an operating instrument was placed in the anteromedial approach, and part of the synovial tissue was clipped with forceps at the typical site of synovial hyperplasia for pathological examination. Then a planer was used to operate alternately in the anteromedial and anterolateral approach, sequentially removing diseased synovial tissue in the surface of the suprapatellar pouch, medial groove, inferomedial groove and intercondylar groove, lateral groove and inferolateral groove, and medial and lateral meniscal. For diseased synovial tissue in the cruciate ligaments as well as on the medial and lateral patellar surfaces, they also need to be cleared together. The most critical surgical approach is to find the synovial space between the synovial layer and the muscle layer, based on this space, the synovial layer, the sub-synovial layer and the adipose layer were nearly completely peeled off, and the stripping depth reached to the muscle layer. The intraoperative image is shown in Fig. 3. Finally, the joint cavity was rinsed thoroughly with a large amount of normal saline, the intra-articular saline was sucked up before suturing the surgical port, and injecting 5ml of local anesthetic along with 40mg of triamcinolone acetonide acetate into the joint cavity from the outer edge of the patella with a syringe for postoperative analgesia and avoiding joint adhesion. There was 1 built-in drainage tube for closed negative pressure drainage. Appropriate pressure dressing with cotton pads and elastic bandages was applied to the affected limb.
Post-operative Management And Rehabilitation Exercises
After the operation, symptomatic treatments such as ice compress, analgesia, stomach protection, and appropriate dehydration were given. Isometric contractions and quadriceps straight leg raises were performed after the patient was awake. After 2 days, the drainage tube was removed depending on the amount of drainage, the dressing was changed every other day, and the wound was properly pressurized and bandaged; after the drainage tube was removed, active knee flexion and extension exercises and continuous passive training (1/day, 30 min/time) were performed, and active and passive training was required 1 week after surgery including bending the knee to ≥ 120°. None of the 19 cases showed excessive joint effusion after the operation, and the patients were instructed to avoid strenuous activities within half a year after discharge and to perform daily straight-leg raising exercises.
Efficacy Evaluation Criteria
The main evaluation index was the recurrence rate at the last follow-up, and the secondary evaluation indexes were the visual analog score (VAS) and the Tegner-Lysholm knee function score [9] at the last follow-up compared with the preoperative data.
Statistical analysis
SPSS 25.0 software package was used for data processing. The VAS and Tegner-Lysholm score (TLS) were used for paired data t-test before knee arthroscopy and during the return visit. All test data were expressed as (X ± s), and the test level was set as α = 0.05.