Osteochondritis Dissecans of the Knee Sonographically Guided Percutaneous Drilling

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1 Technical dvance Osteochondritis Dissecans of the Knee Sonographically Guided Percutaneous Drilling Juan D. erná-serna, MD, Francisco Martinez, MD, Manuel Reus, MD, Juan D. erná-mestre, MD Objective. The purpose of this study was to present a procedure for sonographically guided percutaneous drilling in the treatment of a case of osteochondritis dissecans (OD) of the knee. Methods. 14-year-old boy had OD of the external femoral condyle. Conventional radiography, magnetic resonance imaging, and sonography revealed the osteochondral lesion. Results. This study showed the utility of sonography both in the treatment of OD through percutaneous drilling and in follow-up. Conclusions. On the basis of the good results obtained in the case described here, it is thought that sonographically guided percutaneous drilling may be a good alternative to arthroscopic drilling in cases of early OD lesions without displacement of the fragment. Key words: knee; magnetic resonance imaging; osteochondritis dissecans; percutaneous drilling; sonography. bbreviations MR, magnetic resonance; OD, osteochondritis dissecans; TE, echo time; TR, repetition time Received July 24, 2007, from the Department of Radiology, Virgen de la rrixaca University Hospital, El Palmar, Murcia, Spain. Revision requested ugust 15, Revised manuscript accepted for publication September 5, ddress correspondence to Juan D. erná- Serna, MD, Department of Radiology, Virgen de la rrixaca University Hospital, El Palmar, Murcia, Spain. jdberna@um.es Osteochondritis dissecans (OD) is a common condition in children, adolescents, and young adults. Osteochondritis dissecans of the knee is a lesion of uncertain etiology. Mechanical and traumatic factors are etiologically dominant in OD. 1 3 Commonly, OD occurs at the medial femoral condyle and less frequently at the lateral femoral condyle. 3 Osteochondritis dissecans is generally diagnosed by conventional radiography. Its therapy is determined by the stage of the lesion, and magnetic resonance (MR) imaging is the method of choice for staging. Treatment of OD in the adult knee can be challenging. The treatment options include lesion debridement, drilling, microfracturing of subchondral bone, and transplantation techniques (autologous chondrocyte implantation, autologous osteochondral transplantation, and osteochondral allografts). 3 5 We are not aware of any previous reports of sonographically guided percutaneous drilling in the treatment of a subchondral lesion of the knee by the merican Institute of Ultrasound in Medicine J Ultrasound Med 2008; 27: /08/$3.50

2 Osteochondritis Dissecans of the Knee Case Description 14-year-old boy, a basketball player, was referred to an orthopedic surgeon at our hospital with pain in the right knee that prevented him from practicing his sport. In the initial physical examination, the patient had pain in the anteroexternal sector of the right knee. His range of mobility was complete. The diagnosis of OD of the external femoral condyle of the right knee was reached by the following imaging techniques: (1) plain radiography (Figure 1); (2) MR imaging, which revealed an osteochondral lesion of the external femoral condyle (Figure 1, and C) with a line of high signal intensity between the OD fragment and the underlying bone; stage II OD was established according to the MR imaging classification proposed by ohndorf 1 ; and (3) sonography (Figure 1, D and E), which revealed the subchondral lesion (Figure 1F). The treatment carried out consisted of percutaneous drilling of the OD lesion guided by sonography and with arthroscopic confirmation. The technique was previously explained in detail to the patient and his family, and written consent was obtained. The surgical procedure consisted of the following steps. First, a preoperative sonographic examination was performed with the leg in maximal flexion. The area of the lesion was determined by means of sagittal and transverse sections, and this area was marked on the skin in indelible ink (Figure 1G). Then, puncture of the subchondral bone was performed, in which 3 percutaneous drillings were made in the area marked on the skin, with the patient anesthetized, the leg in maximal flexion, rigorous aseptic measures, and sonographic verification. rthroscopy then confirmed that the drillings had been made in the area of the subchondral lesion. The lesion was then pinned with biodegradable polylactic acid pins (Intra Fix Smart Nails; Conmed-Linvatec, Tampere, Finland). In the immediate postoperative period, the patient started with progressive mobility without support and then underwent rehabilitation with muscle strengthening. fter 1 month, he was allowed to increase his efforts progressively. Imaging studies with plain radiography, MR imaging, and sonography (Figure 2) carried out 2 months after the operation showed a partial repair of the osteochondral defect. Imaging studies, sonography, and plain radiography carried out 20 months after the operation showed complete resolution of the lesion (Figure 3). Figure 1. Preoperative images of OD of the external femoral condyle., nteroposterior radiograph showing an OD lesion (arrow)., Sagittal T2-weighted spin echo MR image (repetition time [TR], 4120 milliseconds; echo time [TE], 106 milliseconds) showing a lesion (arrow) with decreased signal intensity and a rim of high signal intensity surrounding the lesion (continued). 256 J Ultrasound Med 2008; 27:

3 erná-serna et al Figure 1. (continued) C, Sagittal T1-weighted gradient echo MR image (TR, 500 milliseconds; TE, 20 milliseconds) at the same level as showing a rim of high signal intensity surrounding the lesion (arrows). D, Sonographic examination and transducer position for assessing the femoral condyle. E, Longitudinal sonogram showing subchondral bone (arrow) of the normal knee joint; ac, indicates articular cartilage; F, femur; and T, tibia. F, Longitudinal sonogram showing subchondral bony flattening (arrows). G, rea of the lesion marked on the skin (arrow). P indicates patella. E C F D G J Ultrasound Med 2008; 27:

4 Osteochondritis Dissecans of the Knee Figure 2. Images obtained at follow-up 2 months after drilling., nteroposterior radiograph showing partial filling of the subchondral defect (arrow)., Sagittal T2-weighted fast spin echo MR image (TR, 4120 milliseconds; TE, 106 milliseconds) showing one of the trajectories of the drillings in the subchondral lesion (arrows). C, Longitudinal sonogram showing partial filling of the defect and the holes of the drillings (arrows). Discussion Osteochondritis dissecans of the knee can cause substantial patient morbidity and is difficult to treat because of the poor autoreparative capability of cartilage. 4 The diagnosis of OD is based on its plain radiographic appearance, although MR imaging is the technique of choice to determine the stability of the lesion. One of the few studies reported on the evaluation of OD of the knee by use of sonography was that of Gregersen and Rasmussen. 6 The efficacy of sonography has been shown in evaluation of OD lesions of the Figure 3. Images obtained at follow-up 20 months after drilling., nteroposterior radiograph showing complete resolution of the osteochondral defect., Longitudinal sonogram showing a fragment similar to the adjacent subchondral bone with a smooth surface and 1 defect (arrow) corresponding to a drilling. C 258 J Ultrasound Med 2008; 27:

5 erná-serna et al humeral capitellum. 7 The sonographic features of OD depend on the evolutive stage of the lesion. The lesion is initially seen as localized subchondral bony flattening with a normal articular surface, an aspect that was observed in our case. In more advanced evolutive stages, the sonographic images observed in the subchondral bone of the femoral condyles are similar to those seen in the capitellum, showing nondisplaced and slightly displaced fragments as double hyperechoic areas in the capitellar subchondral bone. When the fragment has completely separated from the underlying bone, the osteochondral defect is usually observed in the capitellum. 7 In this study, the utility of sonography was shown in the diagnosis of OD of the external femoral condyle, in the surgical planning of percutaneous drillings of the lesion, and also in the postoperative follow-up. Treatment of OD lesions in the knee is often a matter of debate and depends on several factors, including the patient s age and symptoms and the stability, location, and size of the lesion. 3 Many types of surgical intervention have been proposed for OD treatment, including transarticular drilling, fixation of the fragment, bone grafting, and fragment excision. Its therapy is determined by the stage of the lesion, and MR imaging is the method of choice for staging. The most common sign of unstable OD on MR imaging is a line of high signal intensity between the fragment (OD lesion) and the underlying femur. 1,3,8 Treatment is typically nonsurgical for stable lesions and surgical for unstable lesions. Staging of OD is of the utmost importance for prognosis and therapy. ccording to the OD classification system using MR imaging proposed by ohndorf, 1 MR imaging stage I (stable OD) is a condition generally treated conservatively, and MR imaging stage II (unstable OD) requires arthroscopy with possible intervention. rthroscopy is generally used for the initial surgical treatment and can be a diagnostic procedure as well as a therapeutic tool. Drilling is still the treatment of choice in early stages of OD. In our case, good results in the OD lesion of the external femoral condyle were obtained by means of sonographically guided percutaneous drillings, and arthroscopy helped in fixation of the fragment with biodegradable polylactic acid pins. This procedure is safe and simple and can be carried out without arthroscopy. No difficulty was found during the procedure. In conclusion, this case serves to indicate the utility of sonography for the treatment of OD lesions and for evaluating the progress of fragment healing. We think that sonographically guided percutaneous drilling may well be a feasible alternative to arthroscopic percutaneous drilling in early lesions of a knee without fragment displacement. References 1. ohndorf K. Osteochondritis dissecans: a review and new MRI classification. Eur Radiol 1998; 8: Stäbler, Glaser C, Reiser M. Musculoskeletal MR: knee. Eur Radiol 2000; 10: outin RD, Januario J, Newberg H, Gundry CR, Newman JS. MR imaging features of osteochondritis dissecans of the femoral sulcus. JR m J Roentgenol 2003; 180: Tins J, McCall IW, Takahashi T, Cassar-Pullicino V, shton, Richardson J. utologous chondrocyte implantation in knee joint: MR imaging and histologic features at 1-year follow-up. Radiology 2004; 234: James SL, Connell D, Saifuddin, Skinner J, riggs TW. MR imaging of autologous chondrocyte implantation of the knee. Eur Radiol 2006; 16: Gregersen HE, Rasmussen OS. Ultrasonography of osteochondritis dissecans of the knee: a preliminary report. cta Radiol 1989; 30: Takahara M, Ogino T, Tsuchida H, Takagi M, Kashiwa H, Nambu T. Sonographic assessment of osteochondritis dissecans of the humeral capitellum. JR m J Roentgenol 2000; 174: De Smet, Fisher DR, Graf K, Lange RH. Osteochondritis dissecans of the knee: determining lesion stability and the presence of articular cartilage defects. JR m J Roentgenol 1990; 155: J Ultrasound Med 2008; 27: