D r i l l i n g Tec h n i q u e s f o r Osteochondritis Dissecans Benton E. Heyworth, MDa,*, Eric W. Edmonds, MDb,c, M. Lucas Murnaghan, MD, MEd, FRCSCd,e, Mininder S. Kocher,
MD
a
KEYWORDS Osteochondritis dissecans Drilling Knee KEY POINTS Isolated drilling of an osteochondritis dissecans lesion (OCD), currently performed as an arthroscopic procedure, is most commonly indicated for stable lesions in skeletally immature patients for whom nonoperative treatments fail. Drilling is designed to disrupt the sclerotic margin of a nonhealing OCD lesion and introduce biologic factors from the adjacent healthy cancellous bone to stimulate healing. Three techniques of drilling are most commonly used in the knee, including (1) transarticular drilling, which involves drilling through the articular cartilage to reach the affected subchondral bone under arthroscopic visualization; (2) retroarticular drilling, in which fluoroscopic guidance of Kirschner wire (K-wire) placement allows sparing of the articular cartilage; and (3) notch drilling, wherein the K-wire is placed behind the involved articular surface via entry through the intercondylar notch. Based on multiple reports in the literature, all 3 techniques of drilling have demonstrated high rates of OCD healing and good return to function among studied populations. Because no single technique has demonstrated clear superiority, comparative studies are needed to better elucidate the relative advantages and disadvantages of the techniques.
INTRODUCTION
Osteochondritis dissecans (OCD) is an uncommon, idiopathic disease of subchondral bone, in which disrupted or decreased blood supply to a focal region of bone adjacent to the articular cartilage can lead to softening, fissuring, delamination, and/or frank separation of a segment of the articular surface.1–3 Although OCD has been reported
a Division of Sports Medicine, Department of Orthopedic Surgery, Boston Children’s Hospital, Harvard Medical School, 300 Longwood Avenue, Boston, MA 02115, USA; b Division of Orthopedic Surgery, Rady Children’s Hospital, 3030 Children’s Way, San Diego, CA 92123, USA; c Department of Orthopedic Surgery, University of California San Diego, 200 West Arbor Drive, CA 92103, USA; d Department of Surgery, University of Toronto, Toronto, Ontario, Canada; e Division of Orthopaedics, The Hospital for Sick Children, Toronto, Ontario, Canada * Corresponding author. 300 Longwood Avenue, Hunnewell 217, Boston, MA 02115. E-mail address: [email protected]
Clin Sports Med 33 (2014) 305–312 http://dx.doi.org/10.1016/j.csm.2013.11.007 sportsmed.theclinics.com 0278-5919/14/$ – see front matter Ó 2014 Elsevier Inc. All rights reserved.
306
Heyworth et al
to occur in a variety of joints, including the ankle, elbow, and, more rarely, the shoulder and hip, by far the most commonly affected joint is the knee, with disproportionate involvement of the femoral condyles. Therefore, this report focuses on the techniques used for the treatment of knee OCD. However, the principles of drilling may be generally applicable to all joints, with subtle management differences based on location. Although OCD has been described in adult patients, it is chiefly considered to be a condition of childhood and adolescence, affecting the developing subchondral bone in the skeletally immature patient. Therefore, treatment of juvenile OCD (JOCD) has been the focus of most reports in the literature, with an emphasis on stimulating healing of the subchondral bone before the condition progresses to more advanced stages, for which more technically challenging and invasive techniques, such as fixation and articular resurfacing procedures, are required to prevent arthritis and disability. Stable JOCD lesions primarily involve changes to the subchondral bone without disruption of the smooth surface of overlying articular cartilage. These stable lesions are initially treated with nonoperative methods, such as activity modification (eg, restriction from sports or impact activities), crutch weight-bearing protection, unloader bracing, and brace or cast immobilization.2,3 When these nonoperative modalities fail to heal the OCD (or incomplete healing occurs), then the gold standard for treatment is drilling of the lesion, in which a small K-wire is generally used to disrupt the sclerotic margin of a nonhealing OCD lesion. The theory of this surgical management is that the disruption of the sclerotic margin introduces biologic factors from the surrounding healthy cancellous bone to stimulate healing. This report describes 3 of the most common techniques of drilling, with an emphasis on the technical aspects and theoretical advantages or disadvantages of each. TRANSARTICULAR DRILLING
The technique of transarticular drilling begins with arthroscopic assessment of the OCD lesion, which includes both direct visualization of the appearance of the lesion, and palpation of the margins of the lesion and the surrounding cartilage with an arthroscopic probe. If significant disruption of the contour of the articular cartilage is present, or if gross mobility of the lesion or significant chondral fissuring is seen, consideration of the addition of fixation of the lesion should be made, because occasionally progression of the lesion to an unstable status may have occurred between the time of the most recent MRI and surgery, or the MRI may have failed to reveal certain signs of instability seen during surgery. However, if the lesion is instead deemed to be stable, and the margins of the lesion are clearly delineated, usually through identification of softer cartilage at the transition between affected and unaffected underlying subchondral bone, attention is turned toward drilling of the lesion. Drilling is performed with a small K-wire, most commonly either a 0.062 or 0.045 inches, although the latter is currently favored by most surgeons to minimize disruption of the articular cartilage. The wire is used to penetrate the lesion precisely perpendicular to the chondral surface with a wire driver (Fig. 1A), which often requires introducing the wire percutaneously at several different sites, with varying degrees of flexion or extension of the knee to achieve perpendicularity. Care is taken to advance the wire an appropriate depth through the affected subchondral bone to the deeper, healthier cancellous bone (see Fig. 1B), after which fat bubbles or bleeding from the marrow may be seen intra-articularly (see Fig. 1C). Although overpenetration to the depth of the distal femoral physis should be avoided, no growth disturbances have been reported in association with this technique. The number of penetrations of the Kirschner wire (K-wire) depends on the size of the K-wire and the size of the lesion, although previous
Drilling Techniques for OCD
Fig. 1. (A) Arthroscopic photographs showing perpendicular K-wire placement during transarticular drilling technique. (B) K-wire penetration of the OCD lesion. (C) Fat bubbles confirming adequate penetration of the healthy cancellous marrow of the femoral condyle, deep to the affected subchondral bone.
studies have referred to use of between 6 and 10 passes of the wire,4 with the multiple passes attempting to uniformly cover the lesion,5 being separated by several millimeters so as not to disrupt the macroarchitecture or stability of the lesion. Postoperatively, most authors institute a period of weight-bearing protection for 6 weeks, with initiation of formal physical therapy to facilitate early resumption of normal range of motion and, later, a weight-bearing strengthening program. Serial radiographs are obtained at follow-up visits every 6 to 12 weeks postoperatively to assess the bony healing of the lesion. The primary advantage of the transarticular technique is its relative technical simplicity, the direct visualization of K-wire placement relative to the margins of the lesion, and optimization of the spacing and coverage of drilling passes. In addition, although the occasional stable OCD will demonstrate such smooth contour of the articular surface that fluoroscopic guidance is warranted to confirm the location of the lesion and drilling placement, most cases do not require radiographic assistance. Several retrospective series have demonstrated the high rates of healing and low morbidity associated with the procedure. Aglietti and colleagues6 described full healing by a mean of 4.9 months in 16 knees in 14 children with a mean age of 12.8 years.
307
308
Heyworth et al
At a mean of 4.7 years follow-up, all children remained asymptomatic, with all children having returned to their baseline activity level, including impact athletics. Anderson and colleagues5 reported healing, return to sports, and “normal” or “near-normal” scores on the International Knee Documentation Committee (IKDC) questionnaire in 18 of 20 lesions (90%) by a mean of 4 months in skeletally immature knees. Because only 2 of 4 lesions (50%) in skeletally mature knees in the series healed, the authors recommended alternative primary treatment of stable OCD lesions in patients with closed physes. All 30 knees in 23 children with open physes described by Kocher and colleagues4 demonstrated healing by a mean of 4.4 months (range, 1–11 months), with the mean Lysholm score improving from 58 to 93 and regression analysis correlating younger age with the degree of score improvement. Gunton and colleagues7 recently investigated drilling techniques through a systematic review of the literature, and included 2 other studies on the transarticular approach, in addition to 3 studies described above. The authors pooled the results of the studies’ subjects, concluding that transarticular drilling demonstrated a 91% healing rate at an average of 4.5 months. No complications were reported in any of the 5 studies included. RETROARTICULAR DRILLING
Arthroscopic assessment of the OCD lesion before retroarticular drilling is performed in similar fashion to that described for transarticular drilling. After confirmation of lesion stability, the arthroscopy equipment is removed from the joint and a C-arm fluoroscopy unit is set up for an anteroposterior view of the knee (Fig. 2A). A 0.062- or 0.045-inch K-wire is placed percutaneously through the cortex of the affected condyle, just distal to the distal femoral physis, and advanced so that the tip of the wire penetrates the center of the most distal aspect of OCD lesion, without penetrating the articular surface (see Fig. 2B). With the K-wire left in place, the orientation of the fluoroscopic C-arm is then shifted to obtain a true lateral view of the femoral condyles, with the introduction of a second wire, if necessary, to achieve a perfect center-center position of the wire within the OCD lesion in both planes (see Fig. 2C). This guiding K-wire is then cut short outside of the skin to allow the unobstructed passage of additional K-wires for penetration around the initial wire. The additional passes are made under fluoroscopic guidance via rotation of a parallel wire guide circumferentially around the guiding K-wire in 1-mm increments and sufficient distance from the initial wire, so as to drill the entire OCD lesion, depending on its size. In one described technique,8 the authors report the desired tactile sensation during wire advancement of encountering a “hard end point,” representing the wire reaching the proximal margin of the lesion, with a subsequent “breakthrough sensation” signifying the disruption of the sclerotic rim and penetration of the wire into the most distal subchondral extent of lesion. Edmonds and colleagues9 approximated 15 to 20 wire passes, each with a new percutaneous entry through the skin with the 0.062-inch K-wire, being optimal to achieve adequate drilling in their series, whereas Donaldson and Wojtys10 recommended making a small skin incision over the condyle, through which to advance the K-wire, which they passed 4 to 8 times into the lesion. The postoperative rehabilitation and monitoring approaches after this technique are similar to those used after transarticular drilling. The primary advantage of the retroarticular technique, compared with the transarticular technique, is the preservation of the articular cartilage. The intraepiphyseal approach may allow for more K-wire penetrations, and therefore greater disruption of the sclerotic margin of the OCD lesion without concern for chondral injury. This technique may also allow better access to far posterior condylar OCD lesions, for
Drilling Techniques for OCD
Fig. 2. (A) Intraoperative setup for retroarticular drilling. (B) Clinical photograph, anteroposterior fluoroscopic view, and schematic showing desired technique for retroarticular drilling. (C) Lateral fluoroscopic view (left) and schematic (right) showing desired technique for retroarticular drilling.
which perpendicular K-wire passage can be difficult to visualize intra-articularly with the transarticular approach. Disadvantages include a slightly more involved intraoperative setup, the need for optimal fluoroscopic visualization of the margins of the lesion in 2 planes, and the radiation exposure that stems from the required use of fluoroscopy. Several level IV studies have emerged describing the results of retroarticular drilling, also referred to as extra-articular drilling. Donaldson and Wojtys10 followed 12 of 15 skeletally immature patients who underwent drilling via the above technique for an average of 21 months (range, 8–38 months). In 12 knees, full radiographic healing, complete return to activities, and normal knee examinations were reported by 8.5 months postoperatively, whereas one patient’s lesion progressed to instability and had a “fair” result in the follow-up period. Edmonds and colleagues9 reported a mean time to healing of 11.8 months (range, 1.3–47.3 months) and a mean time of return to activities of 2.8 months (range, 1.3–13.1 months) in 59 children with stable lesions who underwent retroarticular drilling. Importantly, the authors noted that large lesions (>320 mm2) required a longer time to healing, averaging 15.3 months, compared with small lesions (
MD
a
KEYWORDS Osteochondritis dissecans Drilling Knee KEY POINTS Isolated drilling of an osteochondritis dissecans lesion (OCD), currently performed as an arthroscopic procedure, is most commonly indicated for stable lesions in skeletally immature patients for whom nonoperative treatments fail. Drilling is designed to disrupt the sclerotic margin of a nonhealing OCD lesion and introduce biologic factors from the adjacent healthy cancellous bone to stimulate healing. Three techniques of drilling are most commonly used in the knee, including (1) transarticular drilling, which involves drilling through the articular cartilage to reach the affected subchondral bone under arthroscopic visualization; (2) retroarticular drilling, in which fluoroscopic guidance of Kirschner wire (K-wire) placement allows sparing of the articular cartilage; and (3) notch drilling, wherein the K-wire is placed behind the involved articular surface via entry through the intercondylar notch. Based on multiple reports in the literature, all 3 techniques of drilling have demonstrated high rates of OCD healing and good return to function among studied populations. Because no single technique has demonstrated clear superiority, comparative studies are needed to better elucidate the relative advantages and disadvantages of the techniques.
INTRODUCTION
Osteochondritis dissecans (OCD) is an uncommon, idiopathic disease of subchondral bone, in which disrupted or decreased blood supply to a focal region of bone adjacent to the articular cartilage can lead to softening, fissuring, delamination, and/or frank separation of a segment of the articular surface.1–3 Although OCD has been reported
a Division of Sports Medicine, Department of Orthopedic Surgery, Boston Children’s Hospital, Harvard Medical School, 300 Longwood Avenue, Boston, MA 02115, USA; b Division of Orthopedic Surgery, Rady Children’s Hospital, 3030 Children’s Way, San Diego, CA 92123, USA; c Department of Orthopedic Surgery, University of California San Diego, 200 West Arbor Drive, CA 92103, USA; d Department of Surgery, University of Toronto, Toronto, Ontario, Canada; e Division of Orthopaedics, The Hospital for Sick Children, Toronto, Ontario, Canada * Corresponding author. 300 Longwood Avenue, Hunnewell 217, Boston, MA 02115. E-mail address: [email protected]
Clin Sports Med 33 (2014) 305–312 http://dx.doi.org/10.1016/j.csm.2013.11.007 sportsmed.theclinics.com 0278-5919/14/$ – see front matter Ó 2014 Elsevier Inc. All rights reserved.
306
Heyworth et al
to occur in a variety of joints, including the ankle, elbow, and, more rarely, the shoulder and hip, by far the most commonly affected joint is the knee, with disproportionate involvement of the femoral condyles. Therefore, this report focuses on the techniques used for the treatment of knee OCD. However, the principles of drilling may be generally applicable to all joints, with subtle management differences based on location. Although OCD has been described in adult patients, it is chiefly considered to be a condition of childhood and adolescence, affecting the developing subchondral bone in the skeletally immature patient. Therefore, treatment of juvenile OCD (JOCD) has been the focus of most reports in the literature, with an emphasis on stimulating healing of the subchondral bone before the condition progresses to more advanced stages, for which more technically challenging and invasive techniques, such as fixation and articular resurfacing procedures, are required to prevent arthritis and disability. Stable JOCD lesions primarily involve changes to the subchondral bone without disruption of the smooth surface of overlying articular cartilage. These stable lesions are initially treated with nonoperative methods, such as activity modification (eg, restriction from sports or impact activities), crutch weight-bearing protection, unloader bracing, and brace or cast immobilization.2,3 When these nonoperative modalities fail to heal the OCD (or incomplete healing occurs), then the gold standard for treatment is drilling of the lesion, in which a small K-wire is generally used to disrupt the sclerotic margin of a nonhealing OCD lesion. The theory of this surgical management is that the disruption of the sclerotic margin introduces biologic factors from the surrounding healthy cancellous bone to stimulate healing. This report describes 3 of the most common techniques of drilling, with an emphasis on the technical aspects and theoretical advantages or disadvantages of each. TRANSARTICULAR DRILLING
The technique of transarticular drilling begins with arthroscopic assessment of the OCD lesion, which includes both direct visualization of the appearance of the lesion, and palpation of the margins of the lesion and the surrounding cartilage with an arthroscopic probe. If significant disruption of the contour of the articular cartilage is present, or if gross mobility of the lesion or significant chondral fissuring is seen, consideration of the addition of fixation of the lesion should be made, because occasionally progression of the lesion to an unstable status may have occurred between the time of the most recent MRI and surgery, or the MRI may have failed to reveal certain signs of instability seen during surgery. However, if the lesion is instead deemed to be stable, and the margins of the lesion are clearly delineated, usually through identification of softer cartilage at the transition between affected and unaffected underlying subchondral bone, attention is turned toward drilling of the lesion. Drilling is performed with a small K-wire, most commonly either a 0.062 or 0.045 inches, although the latter is currently favored by most surgeons to minimize disruption of the articular cartilage. The wire is used to penetrate the lesion precisely perpendicular to the chondral surface with a wire driver (Fig. 1A), which often requires introducing the wire percutaneously at several different sites, with varying degrees of flexion or extension of the knee to achieve perpendicularity. Care is taken to advance the wire an appropriate depth through the affected subchondral bone to the deeper, healthier cancellous bone (see Fig. 1B), after which fat bubbles or bleeding from the marrow may be seen intra-articularly (see Fig. 1C). Although overpenetration to the depth of the distal femoral physis should be avoided, no growth disturbances have been reported in association with this technique. The number of penetrations of the Kirschner wire (K-wire) depends on the size of the K-wire and the size of the lesion, although previous
Drilling Techniques for OCD
Fig. 1. (A) Arthroscopic photographs showing perpendicular K-wire placement during transarticular drilling technique. (B) K-wire penetration of the OCD lesion. (C) Fat bubbles confirming adequate penetration of the healthy cancellous marrow of the femoral condyle, deep to the affected subchondral bone.
studies have referred to use of between 6 and 10 passes of the wire,4 with the multiple passes attempting to uniformly cover the lesion,5 being separated by several millimeters so as not to disrupt the macroarchitecture or stability of the lesion. Postoperatively, most authors institute a period of weight-bearing protection for 6 weeks, with initiation of formal physical therapy to facilitate early resumption of normal range of motion and, later, a weight-bearing strengthening program. Serial radiographs are obtained at follow-up visits every 6 to 12 weeks postoperatively to assess the bony healing of the lesion. The primary advantage of the transarticular technique is its relative technical simplicity, the direct visualization of K-wire placement relative to the margins of the lesion, and optimization of the spacing and coverage of drilling passes. In addition, although the occasional stable OCD will demonstrate such smooth contour of the articular surface that fluoroscopic guidance is warranted to confirm the location of the lesion and drilling placement, most cases do not require radiographic assistance. Several retrospective series have demonstrated the high rates of healing and low morbidity associated with the procedure. Aglietti and colleagues6 described full healing by a mean of 4.9 months in 16 knees in 14 children with a mean age of 12.8 years.
307
308
Heyworth et al
At a mean of 4.7 years follow-up, all children remained asymptomatic, with all children having returned to their baseline activity level, including impact athletics. Anderson and colleagues5 reported healing, return to sports, and “normal” or “near-normal” scores on the International Knee Documentation Committee (IKDC) questionnaire in 18 of 20 lesions (90%) by a mean of 4 months in skeletally immature knees. Because only 2 of 4 lesions (50%) in skeletally mature knees in the series healed, the authors recommended alternative primary treatment of stable OCD lesions in patients with closed physes. All 30 knees in 23 children with open physes described by Kocher and colleagues4 demonstrated healing by a mean of 4.4 months (range, 1–11 months), with the mean Lysholm score improving from 58 to 93 and regression analysis correlating younger age with the degree of score improvement. Gunton and colleagues7 recently investigated drilling techniques through a systematic review of the literature, and included 2 other studies on the transarticular approach, in addition to 3 studies described above. The authors pooled the results of the studies’ subjects, concluding that transarticular drilling demonstrated a 91% healing rate at an average of 4.5 months. No complications were reported in any of the 5 studies included. RETROARTICULAR DRILLING
Arthroscopic assessment of the OCD lesion before retroarticular drilling is performed in similar fashion to that described for transarticular drilling. After confirmation of lesion stability, the arthroscopy equipment is removed from the joint and a C-arm fluoroscopy unit is set up for an anteroposterior view of the knee (Fig. 2A). A 0.062- or 0.045-inch K-wire is placed percutaneously through the cortex of the affected condyle, just distal to the distal femoral physis, and advanced so that the tip of the wire penetrates the center of the most distal aspect of OCD lesion, without penetrating the articular surface (see Fig. 2B). With the K-wire left in place, the orientation of the fluoroscopic C-arm is then shifted to obtain a true lateral view of the femoral condyles, with the introduction of a second wire, if necessary, to achieve a perfect center-center position of the wire within the OCD lesion in both planes (see Fig. 2C). This guiding K-wire is then cut short outside of the skin to allow the unobstructed passage of additional K-wires for penetration around the initial wire. The additional passes are made under fluoroscopic guidance via rotation of a parallel wire guide circumferentially around the guiding K-wire in 1-mm increments and sufficient distance from the initial wire, so as to drill the entire OCD lesion, depending on its size. In one described technique,8 the authors report the desired tactile sensation during wire advancement of encountering a “hard end point,” representing the wire reaching the proximal margin of the lesion, with a subsequent “breakthrough sensation” signifying the disruption of the sclerotic rim and penetration of the wire into the most distal subchondral extent of lesion. Edmonds and colleagues9 approximated 15 to 20 wire passes, each with a new percutaneous entry through the skin with the 0.062-inch K-wire, being optimal to achieve adequate drilling in their series, whereas Donaldson and Wojtys10 recommended making a small skin incision over the condyle, through which to advance the K-wire, which they passed 4 to 8 times into the lesion. The postoperative rehabilitation and monitoring approaches after this technique are similar to those used after transarticular drilling. The primary advantage of the retroarticular technique, compared with the transarticular technique, is the preservation of the articular cartilage. The intraepiphyseal approach may allow for more K-wire penetrations, and therefore greater disruption of the sclerotic margin of the OCD lesion without concern for chondral injury. This technique may also allow better access to far posterior condylar OCD lesions, for
Drilling Techniques for OCD
Fig. 2. (A) Intraoperative setup for retroarticular drilling. (B) Clinical photograph, anteroposterior fluoroscopic view, and schematic showing desired technique for retroarticular drilling. (C) Lateral fluoroscopic view (left) and schematic (right) showing desired technique for retroarticular drilling.
which perpendicular K-wire passage can be difficult to visualize intra-articularly with the transarticular approach. Disadvantages include a slightly more involved intraoperative setup, the need for optimal fluoroscopic visualization of the margins of the lesion in 2 planes, and the radiation exposure that stems from the required use of fluoroscopy. Several level IV studies have emerged describing the results of retroarticular drilling, also referred to as extra-articular drilling. Donaldson and Wojtys10 followed 12 of 15 skeletally immature patients who underwent drilling via the above technique for an average of 21 months (range, 8–38 months). In 12 knees, full radiographic healing, complete return to activities, and normal knee examinations were reported by 8.5 months postoperatively, whereas one patient’s lesion progressed to instability and had a “fair” result in the follow-up period. Edmonds and colleagues9 reported a mean time to healing of 11.8 months (range, 1.3–47.3 months) and a mean time of return to activities of 2.8 months (range, 1.3–13.1 months) in 59 children with stable lesions who underwent retroarticular drilling. Importantly, the authors noted that large lesions (>320 mm2) required a longer time to healing, averaging 15.3 months, compared with small lesions (
