Impact of monopolar radiofrequency energy on subchondral bone viability

Time to reconsider post arthroscopic osteonecrosis of the knee: a systematic review

The etiology of post-arthroscopic osteonecrosis of the knee (PAONK) is still unknown. The aims of this systematic review were to analyze the main characteristics of patients who developed osteonecrosis after arthroscopy. We considered for inclusion in the review case reports, case series, retrospective and prospective clinical trial, that involved patients who developed osteonecrosis of the knee within 1 year of arthroscopy for meniscal lesion or anterior cruciate ligament rupture with or without chondropathy. In all cases, there was a pre-operative magnetic resonance imaging that excluded the presence of osteonecrosis. We used the MINORS criteria to estimate the risk of bias. A total of 13 studies that involved 125 patients were included in the review. Only 14 out of 55 patients performed the pre-operative MRI after the "window period", which we considered 6 weeks between the onset of symptoms and positive MRI findings. A diagnosis of PAONK was made for 55 patients within 1 year of surgery. Of these, 29% was treated conservatively, while 71% repeated surgery. Osteonecrosis after knee arthroscopy is a reality and surgeon shouldn't underestimate the persistence or re-emergence of symptoms after arthroscopy. It may be due to subchondral insufficiency fractures in osteopenic bone, without evidence of necrosis. However, there are not elements enough to differentiate clinical and radiological characteristics of PAONK from SPONK. Terminology should be simplified, distinguishing subchondral insufficiency fractures of the knee as a precursor of primary osteonecrosis of the knee.

Subchondral fracture caused by unevenly stiffened meniscus after radiofrequency-assisted arthroscopic knee meniscectomy: A case report and review of the literature

•

Although the worsening of symptoms following knee arthroscopy in older patients is often labeled as progression of arthritic symptoms, subchondral insufficiency fracture following arthroscopy may be underdiagnosed.

•

There is a possibility that uneven stiffening of the meniscus causes concentration of stress that resulted in postarthroscopic subchondral fracture.

•

Surgeons should consider avoiding subsequent subchondral fracture when to use radiofrequency in the debridement of a torn meniscus.

Introduction

Causality for postarthroscopic osteonecrosis of the knee is unknown, and related mechanisms have been poorly characterized.

Presentation of case

This report describes a case of a 69-year-old man with subchondral fracture occurring after arthroscopic meniscectomy using a radiofrequency assisted shaver. The patient experienced increasingly intense knee pain 10 months after the meniscectomy. MR imaging revealed postarthroscopic osteonecrosis of the knee in the femoral medial condyle, requiring unicompartmental knee arthroplasty. A mid-coronal cut section of the resected medial femoral condyle showed a linear fracture line parallel to the subchondral bone endplate. Histopathological examination showed prominent callus formation on both sides of the fracture, comprised of reactive woven bone and granulation tissue. The middle portion of the resected medial meniscus was of uneven height, with significant stiffening of the higher side. The stiffened region of the medial meniscus corresponded to the subchondral fracture in the medial femoral condyle.

Discussion

The etiology of post-arthroscopic osteonecrosis of the knee is controversial, but it seems possible that altered knee biomechanics after meniscectomy may predispose patients to osteonecrosis. The findings of the current case suggested that uneven stiffening of the meniscus caused concentration of stress that resulted in postarthroscopic subchondral fracture.

Conclusion

Subchondral insufficiency fracture following arthroscopy may be underdiagnosed. Surgeons need to carefully consider the risk of subchondral fracture following uneven stiffening of the meniscus when to use radiofrequency in the debridement of a torn meniscus.

Postarthroscopy Osteonecrosis of the Knee: Current Concepts

Knee osteonecrosis is a severe disease rapidly leading to end-stage osteoarthritis, which was classified into three categories: spontaneous, secondary, and postarthroscopy. To understand postarthroscopy osteonecrosis of the knee, all the three types of knee osteonecrosis have to be deepened. This article reviewed spontaneous and secondary osteonecroses of the knee, with special focus upon postarthroscopy osteonecrosis, which is a rare form, affecting patients operated for arthroscopic knee surgery, most commonly for meniscectomy. Due to its rarity, patients and surgeons are often unprepared for this complication. A correct diagnosis is essential for appropriate treatment, and also to determine if a preexisting osteonecrosis was present, avoiding medicolegal sequelae, although many authors agree that osteonecrosis (both spontaneous and postarthroscopy) represent unpreventable and unpredictable conditions. In spontaneous osteonecrosis, the treatment is defined according to the size and the degree of the lesion, whereas in postarthroscopy osteonecrosis, the size of the lesion has no prognostic value, and therefore, the choice of the correct treatment is based more on the timing of the diagnosis. A diagnostic and therapeutic algorithm was outlined on the basis of the actual knowledge.

RFE based chondroplasty in wrist arthroscopy indicates high risk for chrondocytes especially for the bipolar application

Background

The application of radiofrequency energy (RFE) has become widespread for surgical performed chondroplasty especially due to the anticipated sealing effect, however the safety of this procedure in the wrist remains unclear. The purpose of this study was to investigate the subchondral temperature during radiofrequency energy (RFE) application simulating chondroplasty in an arthroscopic setting of the wrist.

Methods

A chondroplasty of the lunate fossa was performed during an arthroscopy setting on 14 cadaver arms using monopolar or biopolar RFE. The temperature was recorded simultaneously from 7 predefined anatomical landmarks.

Results

The mean temperature for both application modes did not exceed more than 30°C at all measured points, except for the lunate fossa. The highest subchondral measured peak temperature was 49.35°C (monopolar) and 69.21°C (bipolar) in the lunate fossa. In addition, the temperature decreased for both radiofrequency (RF) devices depending on the distance of the sensors to the RF-probe.

Conclusion

It remains to be questionable how safe RFE can be used for chondroplasty in wrist arthroscopy under continuous irrigation and constant movement to obtain the desired sealing effect. However, the bipolar device should be applied with more caution since peak temperature in the lunate fossa almost reached 70°C even under continuous irrigation.

Postarthroscopy osteonecrosis of the knee

PURPOSE

Spontaneous subchondral osteonecrosis of the knee joint confined to a localized area of one condyle can occur after arthroscopic procedures. Meniscal tears, arthroscopic meniscectomy, and radiofrequency chondroplasty are aetiological factors in the development of osteonecrosis. The aim of this study was to investigate whether the incidence of osteonecrosis increased when mechanical or radiofrequency chondroplasty was used in conjunction with arthroscopic meniscectomy.

METHODS

In this prospective clinical trial, arthroscopic meniscectomy was the primary treatment in 75 patients (mean age 40 ± 13) with stage II and III degenerative changes on the articular cartilage. Patients had to meet the following criteria: 1) have preoperative MRI and plain film radiographs showing no evidence of osteonecrosis; 2) be symptomatic for at least 6 weeks before the preoperative MRI; and 3) have arthroscopically confirmed stage II or III chondral lesion. A preoperative MRI was performed for all patients. For treatment of chondral lesions, debridement with a shaver or chondroplasty with a monopolar RF energy system was used. Patients were divided into three treatment groups. Partial meniscectomy of the medial or lateral (or both) menisci was performed on all patients, but patients in group 2 additionally received mechanical debridement of the chondral lesion, and those in group 3 were additionally treated with RF chondroplasty. Patients in group 1 were treated with partial meniscectomy alone. Patients were re-examined after 6 months, at which time a repeat MRI was performed.

RESULTS

Development of osteonecrosis was detected during the postoperative MRIs of five patients: two in group 1, two in group 2, and one in group 3.

CONCLUSION

The addition of mechanical or RF chondroplasty to meniscectomy did not increase the number of patients with osteonecrosis. Also, RF chondroplasty, which is commonly proposed to be an aetiological factor, resulted in a decrease in the number of patients that developed osteonecrosis.

LEVEL OF EVIDENCE

II.