➢ Osteochondritis dissecans of the knee occurs most frequently in preadolescents and adolescents with open physes but may be seen in adults.
○ A variety of potential etiologies and pathophysiologic pathways have been proposed, most of which center around microtraumatic dysvascularization or necrosis of a focal area of subchondral bone.
○ Experts generally consider osteochondritis dissecans to be an idiopathic phenomenon.
➢ The knee is by far the most common site of osteochondritis dissecans, with other sites of involvement including the ankle and elbow, and, less commonly, the shoulder and hip.
○ The most common location for knee osteochondritis dissecans is the lateral aspect of the medial femoral condyle.
○ The second most common location is the lateral femoral condyle; such lesions tend to be larger and more advanced at the time of presentation.
○ Trochlear, patellar, and tibial plateau osteochondritis dissecans lesions also occur (listed here in descending order according to incidence) but are more rare.
➢ The primary approach for stable osteochondritis dissecans in skeletally immature patients is nonoperative treatment.
○ While there is no clear evidence that synthesizes the most effective form or duration of nonoperative treatment, most authors have described a minimum of three months of treatment to allow for the assessment of potential healing.
○ Therapeutic modalities include protected weight-bearing with crutches, locked hinged knee-bracing, unloader bracing, and simple activity modification with the avoidance of sports and impact activities.
➢ For stable osteochondritis dissecans lesions in skeletally immature patients that do not demonstrate healing with nonoperative measures, and for stable osteochondritis dissecans lesions that are first detected in skeletally mature patients, the standard of care for operative treatment is generally drilling of the lesion.
○ The two principal techniques include transarticular drilling, which is usually performed for femoral condylar lesions in retrograde fashion under arthroscopic visualization, and so-called retroarticular drilling, which is usually performed in an anterograde fashion with fluoroscopic guidance.
○ Both techniques, and others, such as intercondylar notch drilling, are designed to disrupt the sclerotic margin of the osteochondritis dissecans lesion and establish multiple channels between the unaffected, healthy adjacent cancellous bone and the affected subchondral bone of the lesion to allow osseous bridging and osseous healing, the time to which has averaged four to six months in most series.
➢ For unstable osteochondritis dissecans lesions—which can range from in situ lesions with mild chondral fissuring to frank osteochondral loose bodies that have undergone complete separation—operative treatment most commonly consists of arthroscopic or open fixation of the lesion, with or without debridement of osseous surfaces and/or bone-grafting at the interface of the parent bone and progeny bone of the osteochondritis dissecans lesion.
○ While the largest series have described successful healing of the majority of lesions following fixation, the treatment of lesions that fail to heal and/or those with chondral degeneration or minimal bone on the progeny fragment may require application of more advanced cartilage salvage or resurfacing techniques, such as OATS (Osteochondral Autograft Transfer System; Arthrex, Naples, Florida), osteochondral allograft transfer, or autologous cultured chondrocyte implantation.
Introduction and Etiology
First described as a named entity by Konig in a classic German text in 18871, osteochondritis dissecans has more recently been defined by a research study group of high-volume osteochondritis dissecans surgeons, musculoskeletal radiologists, physical therapists, and researchers2 as “a focal, idiopathic alteration of subchondral bone with risk for instability and disruption of adjacent articular cartilage that may result in premature osteoarthritis.”3 While the condition can arise in a number of different joints of the body, in the vast majority of affected individuals only a single joint is involved. The knee is by far the most common site of involvement, and osteochondritis dissecans of the knee will be the focus of the current review.
Osteochondritis dissecans of the knee occurs most frequently in preadolescents and adolescents with open physes. While some authors distinguish this more common entity, traditionally referred to as juvenile osteochondritis dissecans, from the much more rare adult osteochondritis dissecans (i.e., osteochondritis dissecans in a skeletally mature patient), many authors believe that adult osteochondritis dissecans is, in most cases, simply juvenile osteochondritis dissecans that went undiagnosed in the adolescent period4-7. However, proven cases of osteochondritis dissecans arising de novo in the adult years have been reported8. Because of confusion regarding this terminology, we therefore prefer not to use the labels “juvenile” or “adult,” but instead distinguish between osteochondritis dissecans lesions that are diagnosed in the setting of either an open, closing, or closed adjacent distal femoral physis.
While a variety of etiologies and pathophysiologic pathways have been proposed, most of which center around dysvascularization of a focal area of subchondral bone, experts still view osteochondritis dissecans as an idiopathic phenomenon, the precise causal factors of which have not been firmly established and for which there is a clear lack of consensus in the literature2,4. Konig1 first proposed that the condition was related to an inflammatory process. However, many authors have supported a theory of repetitive microtrauma leading to subchondral bone contusion, dysvascularity, and necrosis4,5,9,10. Smaller studies also have demonstrated an association between single episodes of macrotrauma and the subsequent development of osteochondritis dissecans, rather than pattern of overuse or repetitive activities6. Genetic associations have been postulated, both historically11 and more recently12, as has the notion of osteochondritis dissecans as a disturbance in the secondary ossification process of epiphyseal growth13. Shea et al. recently performed an important comprehensive review of all studies involving histological analysis of osteochondritis dissecans specimens and identified eleven studies of adequate methodologic rigor, five of which proposed a traumatic or repetitive stress etiology and two of which identified poor blood supply4. In all likelihood, while a subset of variations of the condition arise via specific vascular, inflammatory, or developmental causes, most cases represent a multifactorial contribution of pathomechanical and biomolecular features that remain incompletely understood2.
Epidemiology and Anatomy
Epidemiological evidence reported by Kessler et al. has advanced our understanding of the incidence of osteochondritis dissecans of the knee in children considerably14. On the basis of a review of medical records from an integrated health-care system of over 1 million patients, the authors established that the incidence of osteochondritis dissecans among patients six to nineteen years old is 9.5 per 100,000 per year, with rates of 15.4 per 100,000 among males and 3.3 per 100,000 among females14. Earlier reports had showed higher incidence rates and less male predominance15,16. The mean age of affected children in the series reported by Kessler et al. was approximately thirteen years, with no reported cases of knee osteochondritis dissecans in children two to five years of age. Children twelve to nineteen years of age had a 3.3-times greater risk of osteochondritis dissecans of the knee than those six to eleven years of age. On the basis of multivariable regression analysis, blacks had the highest odds ratio of osteochondritis dissecans of the knee in comparison with non-Hispanic whites, Hispanics, Asians/Pacific Islanders, and other ethnicities14.
The knee is by far the most common site of osteochondritis dissecans in the body, with other frequently involved joints including the ankle17 and elbow, and, less commonly, the shoulder and hip18. The most frequent location of osteochondritis dissecans of the knee in the coronal plane is the lateral or centrolateral aspect of the medial femoral condyle, and the most common location in the sagittal plane is the central or posterior aspect of the condyle. Kessler et al.14, in a study of 192 patients, reported that 63.6% of condylar knee lesions occurred in the medial femoral condyle whereas 32.5% occurred in the lateral femoral condyle. Kessler et al. also reported that bilateral lesions occurred in 7.3% of affected patients; this percentage was considerably lower than that reported by Cooper et al.19, who noted bilateral disease in 29% of 108 consecutive patients. Evidence suggests that lateral femoral condylar lesions tend to be larger and more advanced at the time of presentation. Patellar, trochlear, and tibial plateau osteochondritis dissecans lesions also occur but are rarer (Fig. 1)20.
Diagnosis, Classification, and Staging
The clinical presentation of osteochondritis dissecans of the knee is quite variable and may be based on the stage of the lesion. Patients with stable lesions often have nonspecific symptoms, including vague or intermittent knee pain or a limp as the presenting complaint. Unstable lesions more commonly cause mechanical symptoms, such as clicking, popping, or locking, particularly if gross instability has led to separation of the progeny fragment and loose body formation. Most symptoms in any stage of osteochondritis dissecans tend to worsen with impact activities, such as running, jumping, or sports involving cutting and/or pivoting. Because osteochondritis dissecans has the potential to be asymptomatic, at least for interval periods, it may be identified incidentally when radiographs are made following an unrelated minor trauma or during the diagnostic workup of another knee condition.
Physical examination signs are similarly variable, with tenderness over the involved condyle and an antalgic gait as the most common findings in patients with stable lesions. Effusions are more common in the setting of unstable lesions, as are crepitus and any mechanical limitations in the range of motion.
Imaging studies that are used for the evaluation of osteochondritis dissecans consist of both radiographs and magnetic resonance imaging (MRI), which have differing, but complementary, utility. Skeletal scintigraphy21,22 and computed tomography (CT) scans have also been shown to be effective for characterizing osteochondritis dissecans lesions and for assessing the response to treatment but are rarely used today in order to avoid exposure to radiation and radioactive tracers in the pediatric population. The common radiographic series for the initial assessment of possible osteochondritis dissecans, including patellar lesions, consists of four views, including anteroposterior, lateral, sunrise/skyline, and tunnel/notch views, the latter of which are particularly useful for characterizing lesions in the posterior aspect of either condyle, which are common locations for osteochondritis dissecans of the knee8. Boys under thirteen years old and girls under eleven years old may demonstrate epiphyseal enchondral accessory and/or secondary ossification abnormalities in the posterior aspect of either condyle, which are locations where osteochondritis dissecans lesions commonly arise23,24, so care must be taken to distinguish pathological findings from normal anatomic or developmental variants in this age group5. Assessment of specific MRI-based features, such as the presence of bone marrow edema adjacent to the affected subchondral bone on T2-weighted scans, is critical for facilitating such diagnostic distinctions, which was nicely articulated by Zbojniewicz and Laor (Fig. 2)24. However, serial radiographs are most commonly employed for monitoring the effect of treatment of osteochondritis dissecans lesions over time, with anteroposterior, lateral, and tunnel/notch views being the most common trio of radiographs to study healing or progression of femoral condylar lesions.
When osteochondritis dissecans is initially diagnosed radiographically, pretreatment MRI scanning should be performed to better characterize the size and stage of the lesion on the basis of the features of the subchondral bone and adjacent cartilage. While a variety of classification systems have been described, the most common currently applied MRI-based classification system was developed by Hefti et al.25 in 1999 (Fig. 3, A). However, an array of criteria beyond those articulated by Hefti et al.25 also may be considered, with stable lesions (Hefti stages 1 and 2) being distinguished from unstable lesions by the presence of intact overlying cartilage without loss of condylar contour or disruption of the continuity of the subchondral bone plate (Fig. 3, B and C). Features of unstable lesions (Hefti stages 3, 4, and 5), which may be variably present, include loss of low-signal subchondral bone plate continuity, chondral fissuring or delamination, an elongated linear hyperintense fluid-like signal pattern across the entire parent bone-progeny bone interface, a second linear hypointense signal deeper to the fluid line, and/or several small hyperintense cyst-like foci or a singular large focus (≥5 mm in diameter) (Fig. 3, D through G)24,26,27.
Nonoperative treatment is the well-established primary approach for stable osteochondritis dissecans lesions involving the knee in skeletally immature patients5,28. While there is no clear evidence demonstrating the most effective form or duration of such measures, most authors have described a minimum of three months of nonoperative treatment to allow for the assessment of potential healing, with a range of modalities employed either singularly or in combination over that period25,28-32.
The traditional approach to nonoperative treatment included prolonged knee immobilization, with use of long-leg casting and protected weight-bearing33. More recently, locked hinged knee braces have been utilized in place of cylindrical casts. Some authors have contended that immobilization is detrimental to chondral health and contributes to stiffness and quadriceps atrophy10,15. Therefore, many clinicians simply recommend activity modification with cessation of athletics and impact activities. Sales de Gauzy et al. demonstrated healing in thirty of thirty-one knees in twenty-four children with a mean age of 11.4 years with use of a protocol of only activity modification until the children were pain-free34. Similarly, Linden reported no progression toward osteoarthritis in a subset of twenty-three children with osteochondritis dissecans lesions who were followed into adulthood, regardless of the treatment approach employed29. In a recent comparative study, Fullick et al. demonstrated that unloader bracing showed more promise than the use of crutches or activity modification alone for promoting healing by protecting the affected side of the joint during weight-bearing28. Larger-scale comparative studies are clearly needed to better elucidate the optimal approach for the nonoperative management of skeletally immature patients.
Recent studies have demonstrated successful healing rates of ≥50% after nonoperative treatment30,31,35. Wall et al. proposed an algorithmic approach to the prediction of healing of stable osteochondritis dissecans lesions in a study of skeletally immature patients who received six months of nonoperative treatment; in that study, 66% of forty-seven lesions healed successfully without operative intervention32. On the basis of the nomogram that was generated from a logistic regression model (Fig. 4), the authors suggested that larger lesion surface area and the presence of mechanical symptoms such as giving-way, swelling, clicking, or locking were predictive of poorer healing, whereas age was interestingly not a significant contributor to the predictive model.
Operative Treatment of Stable Osteochondritis Dissecans
While trialing nonoperative measures is widely considered to be the standard of care for the initial treatment of osteochondritis dissecans in skeletally immature patients, operative treatment is generally recommended as first-line treatment once the distal femoral physis has closed, because of decreased healing potential in the skeletally mature knee. In addition, if follow-up radiographs or serial MRI scans do not show progression toward healing in a skeletally immature patient who has undergone a reasonable period of nonoperative treatment, operative treatment may be recommended.
The standard of care for the operative treatment of stable osteochondritis dissecans is drilling of the lesion. The two principal techniques for condylar lesions include transarticular drilling (Fig. 5), which is usually performed in retrograde fashion under arthroscopic visualization, and retroarticular drilling (also called transepiphyseal drilling or extra-articular drilling), which is usually performed in an anterograde fashion under fluoroscopic guidance (Fig. 6). Both techniques, and others such as intercondylar notch drilling36, share the common principle of using a Kirschner wire to disrupt the sclerotic margin of the osteochondritis dissecans lesion and to establish channels (Fig. 7) between healthy cancellous bone and the dysvascular or necrotic subchondral bone in order to promote osseous bridging and healing, the time to which has averaged four to six months in most series30,37-41. In both techniques, arthroscopy is performed before drilling in order to inspect the lesion, palpate the cartilage with the arthroscopic probe, and confirm its stability, which is characterized by the absence of any gross fragment mobility or chondral fissures at its margin. Bradley and Dandy, in what we believe to be the first report on the transarticular technique, noted that nine of eleven children had healing within twelve months postoperatively42. Additional reports by Aglietti et al.43, Anderson et al.37, and Louisia et al.44 also demonstrated excellent healing rates, with poorer results reported for patients with chondral fissures and closed physes, thereby advancing the concept that additional fixation should be considered for the treatment of unstable lesions and questionably unstable lesions in adult patients. Kocher et al.38, in what we believe to be the largest series of transarticular osteochondritis dissecans drilling, reported on thirty knees in twenty-three patients with a mean age of 12.3 years (range, 8.5 to 16.1 years) who underwent drilling after more than six months of failed nonoperative care. Radiographic healing was seen in all patients at a mean of 4.4 months, with improvement in the mean Lysholm score from 58 to 93.
Lee and Mercurio45 provided the first thorough description of retroarticular osteochondritis dissecans drilling in their report on five lesions in four patients, which included one lesion in the lateral femoral condyle and one in the talus. Four lesions demonstrated healing, with the fifth, unhealed lesion remaining asymptomatic six months after treatment. Donaldson and Wojtys46, Adachi et al.47, and Ojala et al.48 described larger series of skeletally immature patients, the majority of whom showed radiographic healing and resolution of symptoms. Edmonds et al.39 reported return to activities at a mean of 2.8 months postoperatively in all fifty-nine children who underwent retroarticular drilling. Forty-four lesions (75%) showed complete radiographic healing by a mean of 11.9 months postoperatively. Boughanem et al.40 recently reported improvement in mean Lysholm scores (from 70 to 95), Tegner activity scores (from 4 to 7), and visual analog scale (VAS) pain scores (from 6.9 to 1.3), with radiographic stability or improvement in all thirty-four lesions in thirty-one patients at a mean of four years after retroarticular drilling.
The relative advantages of the transarticular technique are that it is technically simpler without the routine use of intraoperative fluoroscopy and it allows for direct arthroscopic visualization of the drilling passes and their spacing relative to the size and margins of the lesion. The advantage of the retroarticular technique is that it does not involve passes of the Kirschner wire through the articular cartilage, thereby protecting the integrity of the joint surface and potentially allowing for a greater number of passes with a larger wire, which may better disrupt the sclerotic margin and initiate healing. In a systematic review of drilling techniques, Gunton et al.41 found no differences between the two techniques in terms of patient-oriented outcome measures. Retroarticular drilling led to radiographic healing of ninety-six (86%) of 111 lesions at a mean of 5.6 months, whereas transarticular drilling resulted in healing of eighty-six (91%) of ninety-four lesions at a mean of 4.5 months41.
Operative Treatment of Unstable Osteochondritis Dissecans
For stable osteochondritis dissecans lesions that have failed to heal despite one or more drilling procedures and for unstable lesions (which can range from in situ lesions with subtle mobility or chondral fissuring at the margins of the lesion to frank osteochondral loose bodies that have undergone complete separation), operative treatment generally consists of fixation of the lesion. Adjunctive techniques performed in conjunction with fixation may include drilling of the lesion, debridement of deep osseous surfaces, and/or bone-grafting at the interface of the parent bone and the progeny bone (i.e., the fragment) at the site of the lesion. The procedure may be performed either arthroscopically or through an open parapatellar arthrotomy on the same side of the patella as the lesion, and a variety of fixation techniques and implant options exist (Fig. 8)49. However, all cases warrant application of several common principles, first espoused by Cahill50, including attempted restoration of the articular surface, use of rigid fixation, enhancement of the blood supply of the osseous interface, and initiation of early postoperative range of motion across the joint surface.
A variety of fixation implant options may be used for the treatment of osteochondritis dissecans. Anderson et al.7 described a series of seventeen skeletally mature patients with unstable lesions that were treated with pinning with one or more Kirschner wires following debridement and bone-grafting. Sixteen of the seventeen lesions healed at a mean of eight months postoperatively. However, because of their inability to achieve reliable or substantial compressive forces and their tendency to bend, Kirschner wires are rarely utilized today, given the relative utility of rigid metal screw fixation. Three basic screw options are commonly used for fixation, including (1) small, solid, flat-headed screws (available in many hand modular implant sets), (2) variable pitch screws51-53, and (3) cannulated partially threaded screws54. Reports on both variable pitch and cannulated screw techniques have shown healing rates of approximately 90% and near-normal functional knee scores in most patients51-54.
More recently, implants made of bioabsorbable/biodegradable material, such as polylactide or polyglycolide—which are variably described as (and are designed to function as) either “pins,” “rods,” “tacks,” “nails,” “darts,” or “screws”—have gained popularity, in part because they generate less artifact during postoperative MRI scanning to assess for healing than metal implants and because they obviate the need for a secondary procedure for implant removal. However, case reports have described sterile abscess formation, synovitic reactions to the foreign material, and implant breakage and/or migration in association with their use55-58. Overall, however, clinical series detailing the use of bioabsorbable implants have shown high rates of healing, improvement of knee function, and low rates of complications59,60. For example, Tabaddor et al.59 reported no cases of the above-described complications in a series of twenty-four knees in twenty-two skeletally immature patients in whom unstable osteochondritis dissecans lesions were treated with bioabsorbable nails, with evidence of healing in sixteen of seventeen patients who underwent postoperative MRI scanning and twenty-two of twenty-four patients who underwent postoperative radiography, correlating with good to excellent functional outcomes in those patients. Three years earlier, Kocher et al.61 had described a series of twenty-six knees in twenty-four skeletally immature patients who underwent fixation of unstable osteochondritis dissecans lesions with one (or more) of four different fixation methods: variable pitch screws (n = 11), bioabsorbable tacks (n = 10), partially threaded cannulated screws (n = 3), or bioabsorbable pins (n = 3). Healing occurred in twenty-two lesions (84.6%) at a mean of six months, with mean functional knee scores of 80% to 85% and with no significant differences according to lesion location, stage, or fixation method.
Another category of stabilization techniques involves biologic fixation with use of cortical “bone pegs”62 or “bone sticks”63 obtained from the proximal medial tibial metaphysis or cylindrical osteochondral autograft plugs obtained from the medial or lateral trochlear ridge or intercondylar notch64,65. Navarro et al.63 and Slough et al.62, in two retrospective series of cortical bone stick fixation, demonstrated satisfactory results in 91% of eleven patients at four years of follow-up and 80% of ten patients at 2.9 years follow-up, respectively. The osteochondral autogenous plug transfer approach for the treatment of osteochondritis dissecans was first described in 199964. Miniaci and Tytherleigh-Strong subsequently reported on an expanded series of twenty knees, eleven of which had open physes66. In that study, the insertion of three to seven plugs (mean, 4.2 plugs) measuring 4.5 × 15 mm led to osseous healing by six months, articular congruity on MRI by nine months, and a normal functional knee score in all patients after a mean duration of follow-up of 1.5 years. Miura et al. similarly reported good to excellent results in eleven of twelve patients who underwent osteochondral autograft plug fixation for the treatment of condylar osteochondritis dissecans, with all twelve lesions demonstrating MRI-based healing within three months after surgery65. The mean lesion size was 2.4 cm2, and the mean plug diameter was 7 mm (with all plugs being 20 mm in depth), with eleven lesions receiving two plugs and one receiving three plugs. Overall, the appeal of biologic techniques is that they share the benefit of bioabsorbable implants, which do not require implant removal, but avoid the disadvantage of potential foreign-body reaction. However, the degree to which they truly achieve compressive fixation has not been well studied and the techniques are generally more invasive, more technically demanding, have the disadvantage of donor-site morbidity, and have only limited supportive literature at this time.
Cartilage Resurfacing and Salvage Techniques for Failed Osteochondritis Dissecans Fixation or Osteochondral Defects Associated with Osteochondritis Dissecans
A somewhat subjective, but critical, set of exceptions to the principle of attempting fixation for unstable osteochondritis dissecans lesions may include the scenario of an osteochondritis dissecans fragment that contains degenerated, macerated, or multiply fissured cartilage or a fragment that has minimal or no bone of sufficient quality to accommodate a fixation implant. Importantly, Kocher et al.61 demonstrated eventual healing of all six of the Hefti stage-525 lesions that underwent fixation in their series. However, for chronically detached lesions (i.e., progeny fragments that likely separated from their corresponding parent bone bed more than six to twelve weeks previously), the necrotic or sclerotic properties of the progeny bone or the expanded size of the progeny cartilage due to synovial fluid intravasation may substantially decrease the chances of successful refixation. In such instances, or in cases of failed fixation or lesion fragmentation, the application of more advanced cartilage salvage or resurfacing techniques, such as autologous osteochondral plug transfer (mosaicplasty), osteochondral allograft transplantation, or autologous cultured chondrocyte implantation, may be used. While the optimal timing and the degree to which a young patient must be symptomatic in order for these more involved techniques to be considered are somewhat controversial, an illustrative long-term follow-up study by Anderson et al.37 demonstrated poor results in the majority of patients in whom excision alone of osteochondritis dissecans fragments was performed, suggesting the importance of addressing the osteochondral defect before degenerative joint disease ensues. Moreover, the ipsilateral meniscus may be at risk of tearing if the defect leads to a mechanical step-off in the articulating contour of the condyle.
Several different retrospective studies have investigated the outcomes of autologous cultured chondrocyte implantation in adolescents. Macmull et al.67 demonstrated 84% good or excellent results at a mean of 5.5 years in a study of thirty-one adolescent patients with a mean age of 16.3 years. Mithöfer et al.68 and Micheli et al.69 showed similarly favorable results at 3.9 and 4.3 years, respectively, in studies of adolescent patients who were managed with autologous cultured chondrocyte implantation, the majority of whom had osteochondritis dissecans. While some believe that the technique should be limited to purely chondral lesions or those with minimal subchondral bone involvement, good results also have been shown when applied to osteochondral defects ≥8 mm deep, which can be treated with a bilayer collagen membrane technique (sandwich technique)70,71. This technique involves packing morselized cancellous bone graft into the osseous defect and covering the graft with a collagen membrane, which serves as the foundation for cultured chondrocyte growth, with cells implanted between this membrane and a second, overlying membrane.
Mosaicplasty techniques, such as Osteochondral Autograft Transfer System (OATS; Arthrex, Naples, Florida), may be effective for smaller contained osteochondral defects associated with failed healing of osteochondritis dissecans lesions. For larger lesions, osteochondral allograft transplantation procedures involving custom-sized grafts obtained from fresh cadaveric condyles may be used72-77. Lyon et al.72 reported on eleven children with a mean age of 15.2 years who underwent fresh osteochondral allograft transplantation for the treatment of osteochondritis dissecans. After a mean duration of follow-up of two years, all patients had achieved complete radiographic graft incorporation, with return to sports activities occurring between nine and twelve months postoperatively. Murphy et al.74 recently reported on a series of forty-three knees in thirty-nine pediatric and adolescent patients with a mean age of 16.4 years who underwent osteochondral allograft transplantation. Twenty-six lesions (60%) were associated with osteochondritis dissecans. The overall rate of graft survival was 90% at ten years, with good intermediate-term International Knee Documentation Committee (IKDC) scores (mean, 75) and Knee Society function scores (mean, 89). Notably, however, the rate of secondary operative treatment among patients with osteochondritis dissecans was 35% (nine of twenty-six), with patients with osteochondritis dissecans representing four of the five allograft revisions (overall rate, 12% [five of forty-three knees]) performed at a median of 2.7 years. While the advantages of this approach include the avoidance of donor-site morbidity and the ability to address large lesions with a single operation, concerns over the phenomenon of creep substitution and long-term maintenance of graft incorporation make additional follow-up studies critical to more widespread adoption of the procedure. Although a number of techniques appear to be feasible as salvage options for failure or osteochondral defects, one theoretical advantage of autologous cultured chondrocyte implantation over mosaicplasty and osteochondral allograft techniques is that the latter procedures remain viable secondary or salvage options in the setting of failed autologous cultured chondrocyte implantation, whereas the converse is less likely to be true.
Source of Funding: There was no external funding source for this research.
Investigation performed at Boston Children’s Hospital, Boston, Massachusetts
Disclosure: None of the authors received payments or services, either directly or indirectly (i.e., via his or her institution), from a third party in support of any aspect of this work. One or more of the authors, or his or her institution, has had a financial relationship, in the thirty-six months prior to submission of this work, with an entity in the biomedical arena that could be perceived to influence or have the potential to influence what is written in this work. No author has had any other relationships, or has engaged in any other activities, that could be perceived to influence or have the potential to influence what is written in this work. The complete Disclosures of Potential Conflicts of Interest submitted by authors are always provided with the online version of the article.
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