Introduction: Osteonecrosis of the knee can be differentiated into two main categories: (1) primary, spontaneous, or idiopathic osteonecrosis and (2) secondary osteonecrosis, which is more prevalent in certain patients such as those who have undergone transplantation, steroid therapy, or patients who have systemic diseases such as lupus, sickle cell, Gaucher’s, and alcoholism.4,6,7,9,10 The concept of osteonecrosis of the knee developing after an arthroscopic meniscectomy has been reported previously.1,4,7-10 The etiology of these cases was not clearly defined, but it is hypothesized that the increased forces transmitted to the already compromised articular surfaces after meniscal resection is the cause. An alternative hypothesis associated with osteonecrosis is that there is an increased risk with use of the radiofrequency device heating up and damaging the articular surface.1,3-5,8,10,11 We present the case of a patient who developed osteonecrosis lesions in both femoral condyles after an arthroscopic anterior interval release with radiofrequency, for anterior knee pain. To our knowledge there are no case reports that cite this complication from this specific procedure.
Case Report: A 39-year-old female was seen for a second opinion in September 2013. She described a year and a half history of left knee pain. In March 2012 she was training for a half-marathon when she began having anterior and medial sided left knee pain. There was no lateral pain reported. She did not have any significant injury that she can remember. Physical therapy resolved her pain initially, but the following year when she was training again her pain recurred.
The patient underwent a left knee arthroscopy in March 2013 at another institution, based on her clinical exam showing mechanical symptoms, as well as a magnetic resonance image (MRI) showing a possible medial meniscus tear. At that time, significant “patellofemoral adhesions from the medial plica up to the patella and down into the fat pad” were seen. “Lateral scarring was noted in this area as well.” There was no evidence of a meniscal tear, or any chondral injury. According to the surgical report, an Arthrocare wand was inserted and the fat pad was resected. An anterior interval release was performed by dissecting the fat pad away from the anterior tibia. Following this resection, “the patella was noted to move easier, and there was full range of motion of the knee.” No technical problems were noted to be associated with the procedure.
The patient presented to our office in September 2013 with continued left knee pain. She stated that subsequent to surgery her pain not only continued, but it worsened. Her preoperative pain was on the medial side, and on exam in September her pain was localized laterally and anteriorly. Clinical photos of her knee through a range of motion are shown (Figure 1). An MRI was obtained in October 2013, which showed anterolateral fat and capsular insufficiency along with extensive abnormal signal in the subchondral marrow of both the distal medial and lateral femoral condyles (Figure 2).
Figure 1. Clinical photo from September 2013 after initial arthroscopy with radiofrequency device. Photo demonstrates lack of anterolateral capsule.
Figure 2. MRI image of (a) coronal and (b) and (c) axial cuts demonstrating multiple areas of increased signal in the femoral condyles.
The patient felt severely limited functionally, and had pain daily. We discussed surgical options with her which led to the decision to proceed with a left knee arthroscopic evaluation of the condyles and open dermal allograft capsular reconstruction, with interpositional fat graft to address the capsular insufficiency. We discussed that we would address the osteonecrosis at a later point. The procedure was performed in November 2013, which demonstrated no chondral damage. Normal medial and lateral menisci were noted. There was lack of an anterolateral capsule of the knee joint from approximately the 3 o’clock position to the patellar tendon. An ArthroFlex (Arthrex, Naples, FL) acellular dermal patch was used to restore the anterolateral joint capsule (Figure 3). The retropatellar fat pad was identified and rotated anterolaterally and sutured to the capsule. Post operatively the patient was treated non weight bearing for eight weeks to protect the osteonecrosis, then toe touch weigh bearing was started. At her first post-operative visit her anterolateral pain was resolved.
Figure 3. Intra-operative photo of (a) deficient anterolateral capsule and (b) ArthroFlex (Arthrex) acellular dermal patch after reconstruction to restore anterolateral joint capsule.
She returned to the office in August 2014 for re-evaluation, continuing to have pain and only able to ambulate with crutches. A MRI was done in October 2014 which showed persistent areas of osteonecrosis, unchanged from her MRI obtained the year prior. She continued to manage her pain conservatively with anti-inflammatories and rest, however she returned in February 2015 continuing to have significant pain. At this time, we discussed doing a subchondroplasty procedure to treat the symptomatic areas of osteonecrosis.
A subchondroplasty is a minimally invasive, fluroscopically-guided procedure that fills the bony defects with AccuFill (Zimmer, Warsaw, IN), a bone substitute material (BSM), that mimics the properties of natural cancellous bone and is resorbed and replaced with new bone. AccuFill BSM is an engineered calcium phosphate mineral compound.
Our patient was taken to the operating room in May 2015, underwent a subchondroplasty and arthroscopy with debridement and synovectomy. No technical problems were associated with the procedure, and her post-operative course has been uneventful. Her five-week post-operative follow up appointment from June 2015 shows restored pain-free range of motion, (Figure 4) and although she has mild pain with activities, the daily throbbing pain has completely resolved. An MRI was obtained in January 2016 demonstrating the interval drilling with sclerotic changes around the tracks of four pre-existing osteonecrotic foci (Figure 5).
Figure 4. Clinical photo demonstrating anterolateral capsule restored, and pain-free range of motion.
Figure 5. Postoperative MRI image (a) T2 coronal, (b) T2 axial, (c) T1 coronal showing sclerotic changes around the pre-existing areas of osteonecrosis. Increased signal in bone marrow has resolved on T2 images.
Follow up from July 2016 demonstrates full and painless range of motion of the left knee. She has no tenderness to palpation at the knee joint, however she has pain with deep squatting. She states that she can walk four miles without any pain, however she does have pain walking up stairs and if she attempts to run.
Discussion: Intra-articular fibrosis can cause significant morbidity within the knee. Arthroscopic techniques provide minimally invasive, efficacious alternatives to open procedures. Anterior interval release is a simple procedure for management of anterior interval scarring.2,12 The use of electrocautery devices for arthroscopy was described first in 1984 by Fox et al.,5 who concluded that electrosurgery offered the benefits of easier accessibility to tight spaces than did mechanical means, with the warning that extreme care must be taken to avoid damage to the articular surface. There have been multiple case reports in the past few years reporting postmeniscectomy osteonecrosis with the use of radiofrequency.3,4,8-10
Osteonecrosis can be a late complication of arthroscopic meniscectomy in patients with altered chondral surfaces. Although the incidence is reported to be low, its pathophysiology is not yet fully understood.4,6 The radiofrequency may cause direct thermal injury and compromise microcirculation to the articular cartilage and underlying bone.3,10,11 This likelihood of occurrence seems to be related to the direct contact with the joint surface and thermal energy. Alternatively, the radiofrequency wand may cause a defect in the articular surface, through which synovial fluid infuses, leading to an elevation in intraosseous pressure and circulatory compromise.10
To the best of our knowledge this is the first case report documenting bilateral femoral condyle osteonecrosis with capsular insufficiency after an anterior interval release, without the presence of meniscal pathology. The literature continues to be controversial regarding how radiofrequency ablation significantly affects the development of osteonecrosis, however, this case report helps us evaluate a unique example of how thermal energy can effect soft tissue and cartilage without addressing any meniscus injury.
- Cetik O et al. Risk of Osteoencrosis of the Femoral Condyle after Arthroscopic Chondroplasty Using Radiofrequency: a prospective clinical series. Knee Surg, Sports Traumatol, Arthrosc. 2009;17 (1): 24-9.
- Chen M, Dragoo J. Arthroscopic Releases for Arthrofibrosis of the Knee. Journal of the American Academy of Orthopedic Surgeons. 2011; 19 (11) :709-16.
- Edwards RB III, Lu Y, Markel MD. Radiofrequency Energy-induced Heating of Bovine Articular Cartilage using a Bipolar Radiofrequency Electrode. Am J Sports Med. 2001;29:263-266.
- Encalada I, Richmond J. Osteonecrosis after Arthroscopic Meniscectomy Using Radiofrequency. 2004; 20 (6): 632-6.
- Fox, J et al. Electrosurgery in Orthopeadics: Part II- Application to Arthroscopy. Comtemp Orthop. 1984;8:37-44.
- Jureus J et al. The natural course of Spontaneous Osteonecrosis of the Knee (SPONK) Acta Orthop. 2013; 84 (4):410-14.
- Mont M, Marker D, Zywiel M, Carrino J. Osteonecrosis of the Knee and Related Conditions. Journal of the American Academy of Orthopedic Surgeons. 2011; 19:482-94.
- Pape D, Seil R, Anagnostakos K, Kohn D. Current Concepts: Postarthroscopic Osteonecrosis of the Knee. 2007; 23 (4): 48-38.
- Patel et al. Osteonecrosis of the Knee: current clinical concepts. Knee Surg, Sports Traumatol, Arthrosc. 1998; 6: 2-11.
- Rozbruch S et al. Osteonecrosis of the Knee following Arthroscopic Laser Meniscectomy. 1996; 12 (2): 245-50.
- Shellock F, Shields C. Radiofrequency Energy-Induced Heating of Bovine Articular Cartilage Using a Bipolar Radiofreqency Electrode. Am J Sports Med. 2000; 28 (5): 720-25.
- Steadman JR et al. Arthroscopic Release for symptomatic scarring of the Anterior Interval of the Knee. Am J Sports Med. 2008; 26 (9): 1763-9.