Infected Baker's Cyst: A New Classification, Diagnosis and Treatment Recommendations

Arthroscopic internal drainage of popliteal cysts with cyst wall resection in pediatric patients

OBJECTIVES

To evaluate the efficacy of arthroscopic internal drainage (AID) and cyst wall resection (CWR) in children with popliteal cysts.

METHODS

This study included 16 pediatric patients with popliteal cysts and received arthroscopy using the double posteromedial (PM) portal system during June 2020 and June 2021 at The General Hospital of Northern Theater Command. Among these pediatric patients, 14 were males and two were females, with the mean age of nine years (range: 7-12 years). The left knee was affected in 12 cases, while the right knee was involved in the rest four cases. All patients underwent MR imaging before the procedure to assess whether there was intra-articular trauma and whether the popliteal cyst communicated with the knee-joint cavity. The MRI results showed that each patient had a simple popliteal cyst that involved a single knee joint without intra-articular trauma, which was classified as Grade-1 (n=3), Grade-2 (n =10) or Grade-3 (n =3) according to the Rauschning and Lindgren grading of knee joint symptoms. Arthroscopy was performed through anterolateral (AL) and PM portals to the knee joint for AID plus CWR, and the surgical outcomes were evaluated based on the Rauschning and Lindgren criteria.

RESULTS

No major vascular or nerve injury occurred during the operation. Postoperative complications such as wound infection and lower-extremity deep venous thrombosis were not recorded in these patients. Complications involving the saphenous nerve or the great saphenous vein or pseudocyst formation were not observed during the follow-up period. All patients completed the follow-up ranging from 3-12 months and were identified to have grade-0 (n=15) and grade-1 (n=1) popliteal cysts based on the Rauschning and Lindgren criteria, indicating significant improvement compared with the preoperative levels (all p<0.05). Moreover, no recurrence was recorded after operation.

CONCLUSION

AID plus CWR is a minimally invasive and safe approach for pediatric patients with popliteal cysts to promote postoperative recovery and reduce the recurrence rate.

Bedside ultrasound-guided aspiration and corticosteroid injection of a baker's cyst in a patient with osteoarthritis and recurrent knee pain

Baker's cyst accompanying knee osteoarthritis represents a common cause of knee pain presenting to the emergency department. In this case report, a 56-year-old male presented with atraumatic left knee pain and swelling. Radiographically, he had tricompartmental osteoarthritis and was found to have a baker's cyst on duplex ultrasound. Using point-of-care ultrasound, the cyst was aspirated and corticosteroids were injected. The patient tolerated the procedure well and was discharged with a compression wrap and orthopedic follow-up. Baker's cyst aspiration with corticosteroid injection represents a safe alternative treatment option for patients. In some cases, this treatment may be definitive. Orthopedists currently use this procedure to reduce pain and improve function for patients with chronic knee ailments related to baker's cysts. As demonstrated in this case report, implementing this bedside procedure in the emergency department with orthopedic follow-up expands non-surgical, non-narcotic treatment options for patients with chronic knee pain secondary to Baker's cysts with osteoarthritis.

A comparison of the clinical effects of arthroscopic treatment for popliteal cyst between techniques using one posteromedial portal and two posteromedial portals

There is a lack of research comparing the clinical effects of arthroscopic treatment of popliteal cysts between the one posteromedial portal (OPP) technique and the two posteromedial portals (TPP) technique. The aim of this study was to evaluate and compare the clinical efficacy of arthroscopic treatment for popliteal cysts between the 2 techniques.Patients with symptomatic popliteal cysts after surgery were retrospectively invited to participate in this study. They received arthroscopy treatment via the OPP technique or the TPP technique. At the final follow-up, the Rauschning and Lindgren criteria and the Lysholm score were used for clinical evaluation. Moreover, magnetic resonance imaging was performed to detect the recurrence of cysts postoperatively.Finally, 53 patients with symptomatic popliteal cysts were included in this study, including 25 in the OPP group and 28 in the TPP group. The operation time of the TPP group was significantly longer than that of the OPP group (P < .001). In the OPP group, the cysts disappeared in 17 patients and reduced in size in 8 patients. In the TPP group, the cysts disappeared in 23 patients and reduced in size in 5 patients. According to the Rauschning and Lindgren classification, the recurrence rate was significantly lower in the TPP group (0%) than in the OPP group (4%) (P = .03). In addition, there was no significant difference in the Lysholm score between the OPP group and the TPP group (P = .77).TPP technique is more effective and superior than OPP technique for the treatment of popliteal cysts.