Dissecting popliteal cyst resulting from a fragmented, dislodged metal part of the patellar component after total knee arthroplasty

Two-stage revision knee arthroplasty for metallosis in a patient with rheumatoid arthritis: A case report

We report a successful case of two-stage revision total knee arthroplasty performed for treating painless metallosis after total knee arthroplasty with a metal-backed patella. A 63-year-old woman diagnosed with rheumatoid arthritis underwent left total knee arthroplasty with a metal-backed patella at 32 years of age. The patient did not have knee pain; however, knee joint swelling, a strange noise, and pigmentation were reported 4 years ago. Radiographs showed cloud and metal-line signs anteriorly and posteriorly at the femoral condyle. Therefore, a two-stage surgery was performed for infection prevention and ease of performing posterior synovectomy. The patient underwent initial synovectomy via a posterior approach, followed by anterior synovectomy and revision total knee arthroplasty. Synovectomy was performed well without perioperative infection or failure of wound healing. In cases with metallosis after total knee arthroplasty, the two-stage revision total knee arthroplasty should be considered, depending on the degree of synovial proliferation and the risk of complications.

Ruptured Popliteal Cysts Mimicking Deep Vein Thrombosis in Well-Functioning Total Knee Replacements: Report of Two Cases and Review of Literature

Background

Implant wear and loosening with eluding metal/polythene debris are commonly implicated in the occurrence of Baker’s cysts in post-operative total knee replacement (TKR) patients, who present with post-operative pain and swelling, mimicking deep venous thrombosis. However, we present two symptomatic cases presenting with ruptured Baker’s cysts post-TKRs, with no evidence of implant loosening or wear.

Cases Report

The 1st patient was a 55-year-old male, who underwent TKR for Grade 4 bilateral knee osteoarthritis and presented with acute onset of pain and swelling over the left popliteal fossa, which progressed to involve the calf. Radiographs showed no sign of infection or loosening, and venous color Doppler and magnetic resonance imaging (MRI) showed a hy-poechoic collection in the intermuscular plane at the upper part of popliteal fossa. Histological examination of the aspirated fluid showed mixed features of cystic fluid and a resolving hematoma. There was complete resolution of the 4 months with rest and graduated physiotherapy.

The 2nd patient was a 51-year-old female who developed the cystic swelling 2 years after the surgery, and the ultrasound showed hypoechoic echoes in a Baker’s cyst-like collection. Cytological findings were suggestive of hemorrhagic nature of the aspirate, without any evi-dence of polyethylene debris, and the cultures were sterile. She became asymptomatic over 4 weeks with conservative management; the swelling resolved after 3 months.

Conclusion

Majority of the cases in literature show implant loosening as cause of popliteal cysts after TKRs, however present cases highlight alternative mechanisms, and there are good chances of self-resolution of cysts with conservative treatment in such cases.

Arthroscopy-Assisted Treatment of Wear Debris Pseudotumor After Total Knee Arthroplasty: A Case Report

Background

Wear debris pseudotumors are a rare complication after total knee arthroplasty (TKA) and have seldom been reported in the recent literature. There is no consensus on the best therapeutic method, but the high quality curative treatment, safe, low invasive treatments are required for the patients.

Case presentation

In this paper, we present the case of a 74‐year‐old man with a wear debris pseudotumor after TKA with symptoms of severe pain and functional disability of his right knee. X‐ray examination showed that the medial compartment of the right knee was narrowing. Magnetic resonance imaging (MRI) and Doppler ultrasound both revealed a polycystic mass at the posteromedial side of the patient's right knee. Considering the bad health condition and the minimally invasive surgery requirement of this senior patient, arthroscopic knee debridement and percutaneous cystic mass suction were carried out simultaneously. Video arthroscopy of the right knee showed visible inflammatory soft tissue, obvious polyethylene fragments, wear of the polyethylene prothesis, and a broken polyethylene insert. The intraarticular polyethylene wear debris was removed as much as possible, and inflammatory soft tissue was debrided and sent for pathology. Postoperative pathology showed polyethylene debris in the soft tissue with an apparent multinucleated giant cell response, which was consistent with foreign body granuloma. All clinical manifestation was improved and Lysholm scores were significantly better at one year with this treatment, increasing from 32 points to 71 points.

Conclusion

After two years of follow‐up, the patient's knee joint was significantly relieved from soreness and pain, and walking was not significantly restricted. Our treatment could not address the root cause of the wear debris pseudotumor, which was due to prosthesis failure, but sometimes, such an approach is the safest, most economical, and most effective choice for patients who are intolerant to reoperation.

Giant Synovial Cyst of the Anterior Compartment: An Unusual Cause of Chronic Knee Pain After Trauma

There is almost no literature describing the management and rationale for intervention for posttraumatic, extra-articular synovial cysts of the knee. We describe the very rare case of a 45-year-old blind man who developed chronic knee pain after a traumatic injury. He was found to have a giant, posttraumatic, true synovial cyst of the knee in an extra-articular location and migrating down the anterior compartment. The surgical management, potential complications, and rationale for intervention are discussed.

Fixation strength comparison of onlay and inset patellar implants

Patellar implant fixation continues to be one of the most troublesome areas in total knee arthroplasty (TKA). It has been reported that patellofemoral complications in TKA are responsible for almost half of all re-operations. The literature review revealed the rate of primary all-polyethylene patellar implant loosening ranging 1%-4.2% [Berend ME, Ritter MA, Keating EM, Faris PM, Crites BM. The failure of all-polyethylene patellar components in total knee replacement. Clin Orthop 2001;388:105-11, Chew JT, Stewart NJ, Hanssen AD, Luo ZP, Rand JA, An KN. Differences in patellar tracking and knee kinematics among three different total knee designs. Clin Orthop 1997;345:87-98, Barrack RL, Wolfe MW, Waldman DA, et al. Patellar resurfacing in total knee arthroplasty: a five to seven year follow-up of prospective, randomized, double-blind study. Proceedings of Sixty-Seventh Annual Meeting of the American Academy of Orthopaedic Surgeons 2000. p. 547]. The loosening rates for metal-backed or following patellar component revisions were considerably higher [Chew JT, Stewart NJ, Hanssen AD, Luo ZP, Rand JA, An KN. Differences in patellar tracking and knee kinematics among three different total knee designs. Clin Orthop 1997;345:87-98, Jordan LR, Sorrells RB, Jordan LC, Olivo JL. The long-term results of a metal-backed mobile bearing patella. Clin Orthop 2005;436:111-8, Berger RA, Lyon, JH, Jacobs JJ, Barden RM, Berkson EM, Sheinkop MB, et al. Problems with cementless total knee arthroplasty at 11 years followup. Clin Orthop 2001;392:196-207, Ritter MA, Pierce MJ, Zhou H, Meding JB, Faris PM, Keating EM. Patellar complications (total knee arthroplasty). Effect of lateral release and thickness. Clin Orthop 1999;367:149-57] Onlay and inset patellar components with variable fixation surface geometry are currently available for clinical use. The purpose of this study was to quantify the shear disassociation strength for both onlay and inset patellar fixation techniques. The variation in host material was minimized by the use of synthetic patellae, which has been previously validated in implant fixation studies. The testing revealed that inset patellar fixation resistance to shear disassociation was 25% higher than onlay patellae (p=0.0002).

Multilobulated popliteal cyst after a failed total knee arthroplasty

Popliteal cyst is a rare finding after total knee arthroplasty (TKA), but when present, it might indicate a malfunction of the TKA related to generation of wear-particles, or loosening. We present a case of a multilobulated popliteal cyst developing in a patient 8 years after primary TKA. The cyst was associated with a mechanical prosthetic loosening. The primary complaint of the patient was pain in the posterior region of the knee. A two-stage procedure consisting of cyst excision at first, followed after 5 months by a revision TKA was performed. Intraoperatively, a darkish, multilobulated cyst with a well-defined thick wall filled with fluid containing polyethylene debris, communicating with the knee joint was found. After 3 years of follow-up, the patient was satisfied and walked without the support of a cane. The patient presented a satisfactory knee range of motion. Clinical, radiological and ultrasound investigations ruled out popliteal cyst recurrence. A dissecting popliteal cyst associated with a failed TKA should be excised because it contains polyethylene debris that constitutes an induced factor for prosthetic loosening. A two-stage procedure with quite a long time in-between, as presented in this paper, can be a useful alternative to manage such a problem, in particular in very old patients associated with other medical problems.

A large metallic cyst caused by wear particles after total knee arthroplasty

INTRODUCTION

A symptomatic cyst is an uncommon complication after total knee arthroplasty (TKA). We present a case of a 77-year-old woman with a large cyst in the right knee caused by metal wear debris from the failure of a Miller-Galante I TKA performed 13 years earlier.

CASE PRESENTATION

The patient was treated with a two-stage operation including revision of the TKA followed by excision of the cyst, because there was a direct communication between the joint cavity and the cyst, and because the patient reported pain corresponding to the cystic area after revision. The patient was pain-free and had a satisfactory result 17 months after the second operation, without recurrence of cyst formation.

CONCLUSION

We recommend two-stage surgery in which the first-stage is correction of the intra-articular pathology with revision TKA and the second-stage is excision of the cyst.