Osteochondritis dissecans of the elbow: Histopathological assessment of the articular cartilage and subchondral bone with emphasis on their damage and repair

Osteochondritis dissecans of the elbow: recent evolution of pathogenesis, imaging, and treatment modalities

Background

The etiology and pathogenesis of osteochondritis dissecans (OCDs) lesions remain controversial.

Methods

This review presents the recent evolution about the healing, imaging, pathogenesis, and how to treat OCD of the capitellum in overhead athletes.

Results

Compressive and shear forces to the growing capitellum can cause subchondral separation, leading to OCD, composed of 3 layers: articular fragment, gap, and underlying bone. Subchondral separation can cause ossification arrest (stage IA), followed by cartilage degeneration (stage IB) or delayed ossification (stage IIA), occasionally leading to osteonecrosis (stage IIB) in the articular fragment. Articular cartilage fracture and gap reseparation make the articular fragment unstable. The mean tilting angle of capitellar OCD is 57.6 degrees in throwers. Anteroposterior radiography of the elbow at 45 degrees of flexion (APR45) can increase the diagnostic reliability, showing OCD healing stages, as follows: I) radiolucency, II) delayed ossification, and III) union. Coronal computed tomography and magnetic resonance imaging with an appropriate tilting angle can also increase the reliability. MRI is most useful to show the instability, although it occasionally underestimates. Sonography contributes to detection of early OCD in adolescent throwers on the field. OCD lesions in the central aspect of the capitellum can be more unstable and may not heal. Cast immobilization has a positive effect on healing for stable lesions. Arthroscopic removal provides early return to sports, although a large osteochondral defect is associated with a poor prognosis. Fragment fixation, osteochondral autograft transplantation, and their hybrid technique have provided better results.

Discussion

Further studies are needed to prevent problematic complications of capitellar OCD, such as osteoarthritis and chondrolysis.

[Treatment of osteochondritis dissecans]

Osteochondritis dissecans (OD) is a rare condition with an incidence of 30/100,000. It especially affects male patients aged 10-20 years old. During the staged progression the osteochondral fragments can detach from their base. These can damage the adjacent articular cartilage, which can lead to premature osteoarthritis. Most commonly affected are the knee, ankle and elbow joints. The exact pathogenesis of OD has so far not been clearly confirmed. Several risk factors that can lead to the development of OD are discussed. These include repeated microtrauma and vascularization disorders that can lead to ischemia of the subchondral bone and to a separation of the fragments close to the joint and therefore to the development of free joint bodies. For an adequate clarification patients should undergo a thorough radiological evaluation including X‑ray imaging followed by magnetic resonance imaging (MRI) to assess the integrity of the cartilage-bone formation with determination of the OD stage. The assessment is based on criteria of the International Cartilage Repair Society (ICRS). The instability of the cartilage-bone fragment increases with higher stages. Stages I and II with stable cartilage-bone interconnection can be treated conservatively. For stages III and IV, i.e., instability of the OD fragment or the presence of free fragments, surgical treatment should be performed. Primarily, refixation of a free joint body should be carried out depending on the size and vitality of the fragment. In cases of unsuccessful conservative treatment or fixation, a debridement, if necessary in combination with a bone marrow stimulating procedure, can be employed corresponding to the size of the defect. For larger cartilage defects, an osteochondral graft transplantation should be considered. Overall, OD lesions in stages I and II show a good healing tendency under conservative treatment. In cases of incipient unstable OD, refixation can also lead to good clinical and radiological results.

Patient-Specific iPSC-Derived Models Link Aberrant Endoplasmic Reticulum Stress Sensing and Response to Juvenile Osteochondritis Dissecans Etiology

Juvenile osteochondritis dissecans (JOCD) is a pediatric disease, which begins with an osteonecrotic lesion in the secondary ossification center which, over time, results in the separation of the necrotic fragment from the parent bone. JOCD predisposes to early-onset osteoarthritis. However, the knowledge gap in JOCD pathomechanisms severely limits current therapeutic strategies. To elucidate its etiology, we conducted a study with induced pluripotent stem cells (iPSCs) from JOCD and control patients. iPSCs from skin biopsies were differentiated to iMSCs (iPSC-derived mesenchymal stromal cells) and subjected to chondrogenic and endochondral ossification, and endoplasmic reticulum (ER)-stress induction assays. Our study, using 3 JOCD donors, showed that JOCD cells have lower chondrogenic capability and their endochondral ossification process differs from control cells; yet, JOCD- and control-cells accomplish osteogenesis of similar quality. Our findings show that endoplasmic reticulum stress sensing and response mechanisms in JOCD cells, which partially regulate chondrocyte and osteoblast differentiation, are related to these differences. We suggest that JOCD cells are more sensitive to ER stress than control cells, and in pathological microenvironments, such as microtrauma and micro-ischemia, JOCD pathogenesis pathways may be initiated. This study is the first, to the best of our knowledge, to realize the important role that resident cells and their differentiating counterparts play in JOCD and to put forth a novel etiological hypothesis that seeks to consolidate and explain previously postulated hypotheses. Furthermore, our results establish well-characterized JOCD-specific iPSC-derived in vitro models and identified potential targets which could be used to improve diagnostic tools and therapeutic strategies in JOCD.

Staging of osteochondritis dissecans of the elbow based on pathologic progression in the partially detached articular fragment

BACKGROUND

Osteochondritis dissecans (OCD) is considered to show the following stages of pathologic progression: IA, nearly normal-cartilaginous; IB, deteriorated-cartilaginous; IIA, cartilage-ossifying; and IIB, cartilage-osteonecrotic. However, the validity of this pathologic staging for OCD has yet to be confirmed in a large number of cases.

PURPOSE

The aim of the present study was to confirm the clinical validity of the proposed pathologic staging of OCD.

METHODS

The subjects were 74 patients (mean age, 14.2 years; mean skeletal age score, 25.6 points) with capitellar OCD. Partially detached articular fragments were surgically removed and were examined histologically. The articular fragments were independently assessed by 5 observers, and the reliability of assessment was examined. The correlation between the pathologic stages and the clinical data was analyzed.

RESULTS

The reliability of the assessment among 5 observers was almost perfect. OCD stages of IA, IB, IIA, and IIB were evident in 8, 36, 10, and 20 patients, respectively. OCD-I (cartilaginous) and OCD-II (osteochondral) corresponded significantly to radiographic stage I (radiolucency) and stage II (delayed ossification), respectively. The pathologic OCD stages were significantly correlated with the clinical data, including the period from symptom onset to surgery, patient age, and the skeletal age score (P < .01).

CONCLUSION

Our results confirmed that the proposed pathologic staging of OCD corresponds to the observed clinical progression of OCD, thus validating the staging system. Our findings revealed that OCD begins with separation beneath the epiphyseal cartilage, which is programmed to be replaced with bone. When a stage IA articular fragment has remained partially detached for a prolonged period, the epiphyseal cartilage may be deteriorated and become degenerated, and subsequent ossification may not occur, as is evident in OCD-IB. In contrast, stage IA with a vascular supply through the fibrocartilaginous connection can progress to stage IIA. During the prolonged period in which the osteochondral articular fragment remains ununited, microtrauma can cause to disturb the blood supply to the bony fragment, resulting in osteonecrosis (stage IIB).

Osteochondritis Dissecans: Current Understanding of Epidemiology, Etiology, Management, and Outcomes

➤

Osteochondritis dissecans occurs most frequently in the active pediatric and young adult populations, commonly affecting the knee, elbow, or ankle, and may lead to premature osteoarthritis.

➤

While generally considered an idiopathic phenomenon, various etiopathogenetic theories are being investigated, including local ischemia, aberrant endochondral ossification of the secondary subarticular physis, repetitive microtrauma, and genetic predisposition.

➤

Diagnosis is based on the history, physical examination, radiography, and advanced imaging, with elbow ultrasonography and novel magnetic resonance imaging protocols potentially enabling early detection and in-depth staging.

➤

Treatment largely depends on skeletal maturity and lesion stability, defined by the presence or absence of articular cartilage fracture and subchondral bone separation, as determined by imaging and arthroscopy, and is typically nonoperative for stable lesions in skeletally immature patients and operative for those who have had failure of conservative management or have unstable lesions.

➤

Clinical practice guidelines have been limited by a paucity of high-level evidence, but a multicenter effort is ongoing to develop accurate and reliable classification systems and multimodal decision-making algorithms with prognostic value.

Treatment of advanced stage osteochondrosis dissecans in the adolescent elbow using a hyaloronic acid-based scaffold: a case series of 5 patients

INTRODUCTION

Osteochondrosis dissecans (OCD) is considered to be one of the main causes for pain, discomfort and morbidity in the pediatric elbow joint. Few treatment options, such as microfracture or autologous transplantation, of osteochondral bone grafts have been described to address advanced OCD. The aim of this retrospective case series is to present preliminary clinical and radiologic findings following advanced stage OCD repair using a novel combination of a hyaluronic acid-based scaffold with autologous iliac crest bone grafting.

MATERIALS AND METHODS

Five adolescents, who underwent treatment of OCD (grade 3 or 4 according to Nelson) using a combination technique of defect debridement, transplantation of cancellous iliac crest bone and application of a HYALOFAST® membrane (Anika Therapeutics S.r.L., Italy), were re-assessed using clinical and radiologic examinations (defect diameter, depth, sclerosis, congruency, fragmentation, dissection, radiolucency, growth plate status; MRI) after a minimum of 2 years (mean, 34 months; range, 24-45) postoperatively. Dedicated outcome scores (Numeric Rating Scale [NRS], Pediatric Outcome Data Collection Instrument [PODCI], Mayo Elbow Performance Score [MEPS], and Timmerman-Andrews Score [TIMM] were collected.

RESULTS

All patients reported a NRS score of 0. The mean total TIMM, MEPS and PODCI (Global Functioning Scale) scores were 189 (range 165-200), 94 (range, 70-100), and 92 (range 83-98; normative score 47; range 35-55), respectively, indicating good to excellent clinical outcomes. The radiographic analysis showed overall improvements with regard to OCD width and depth reduction (35%, - 27-100%; 52%, 4-100%), but full resolution in only 2 of 5 cases. Elbow motion improved slightly after surgery. No complications were noted.

CONCLUSION

This study showed promising clinical short- to mid-term results in adolescent patients with advanced OCD using a novel surgical treatment combination. Radiographic results showed partial healing; hence, residual changes should be monitored over a longer period.

Progression of Epiphyseal Cartilage and Bone Pathology in Surgically Treated Cases of Osteochondritis Dissecans of the Elbow

BACKGROUND

Although a variety of pathologic conditions associated with osteochondritis dissecans (OCD) have been reported, the pathological progression has remained unclear.

HYPOTHESIS

Separation of the immature epiphyseal cartilage is an early event in OCD, and osteonecrosis in the articular fragment is a late event.

STUDY DESIGN

Case Series; Level of evidence, 4.

METHODS

The participants were 26 boys (mean age, 13.8 years; mean skeletal age score for the elbow, 24.6 points) with capitellar OCD who underwent osteochondral autograft transplantation. A total of 28 cylindrical osteochondral plugs, including the articular fragment, an intermediate layer, and proximal epiphyseal bone, were harvested from the central area of the capitellum and were examined histologically. The articular fragments of OCD were independently assessed by 5 observers and divided into 4 pathological variations: IA, nearly normal-cartilaginous; IB, deteriorated-cartilaginous; IIA, cartilage-ossifying; and IIB, cartilage-osteonecrotic. The reliability of assessment and the correlation of the pathological variations with the clinical data were examined.

RESULTS

The reliability of the assessment among 5 observers was almost perfect (Cohen kappa value = 0.91). OCD variations of IA, IB, IIA, and IIB were evident in 5, 10, 5, and 6 patients, respectively. OCD-I (cartilaginous) and OCD-II (osteochondral) corresponded significantly to radiographic stage I (radiolucency or slight calcification with open physis) and stage II (delayed ossification or bony fragment), respectively (Cohen kappa value = 0.79; percentage agreement = 81%). The pathological OCD variations were significantly correlated with the clinical data, including the period from symptom onset to surgery, patient age, and the skeletal age score (P < .01, in each).

CONCLUSION

The present study has revealed that the pathological variations correspond to the progression of OCD, thus proving our hypothesis. OCD-IA was shown to be an early lesion caused by separation of the immature epiphyseal cartilage. OCD-IB appeared to result from ossification arrest over a prolonged period from the onset of OCD-IA, whereas OCD-IIA showed delayed ossification in the epiphyseal cartilage where vascularization from the surrounding bone had been established. Osteonecrosis in OCD-IIB was shown to be a late pathological event caused by disruption of the vascular supply to OCD-IIA.

Ulnar collateral ligament dysfunction increases stress on the humeral capitellum: a finite element analysis

Background

Repetitive mechanical stress on the elbow joint during throwing is a cause of ulnar collateral ligament dysfunction that may increase the compressive force on the humeral capitellum. This study aimed to examine the effects of ulnar collateral ligament material properties on the humeral capitellum under valgus stress using the finite element method.

Methods

Computed tomography data of the dominant elbow of five healthy adults were used to create finite element models. The elbows were kept at 90° of flexion with the forearm in the neutral position, and the ulnar collateral ligament was reproduced using truss elements. The proximal humeral shaft was restrained, and valgus torque of 40 N·m was applied to the forearm. The ulnar collateral ligament condition was changed to simulate ulnar collateral ligament dysfunction. Ulnar collateral ligament stiffness values were changed to 72.3 N/mm, 63.3 N/mm, 54.2 N/mm, 45.2 N/mm, and 36.1 N/mm to simulate ulnar collateral ligament laxity. The ulnar collateral ligament toe region width was changed in increments of 0.5 mm from 0.0 to 2.5 mm to simulate ulnar collateral ligament loosening. We assessed the maximum equivalent stress and stress distribution on the humeral capitellum under these conditions.

Results

As ulnar collateral ligament stiffness decreased, the maximum equivalent stress on the humeral capitellum gradually increased under elbow valgus stress (P < .001). Regarding the change in the ulnar collateral ligament toe region width, as the toe region elongated, the maximum equivalent stress of the humeral capitellum increased significantly under elbow valgus stress (P < .001). On the capitellum, the equivalent stress on the most lateral part was significantly higher than that on other parts (P < .01 for all).

Conclusion

Under elbow valgus stress with elbow flexion of 90° and the forearm in the neutral position, ulnar collateral ligament dysfunction increased equivalent stress on the humeral capitellum during the finite element analysis. The highest equivalent stress was noted on the lateral part of the capitellum.

Lateral wall fixation with bone pegs for advanced osteochondritis dissecans of the humeral capitellum

Background and hypothesis

It is generally considered that fragment fixation with bone pegs (FFBP) for osteochondritis dissecans (OCD) of the humeral capitellum can be indicated for stages I and II according to the International Cartilage Repair Society (ICRS) classification of OCD and it is difficult to obtain complete bone union for advanced lesions. However, the clinical and radiologic results of FFBP with cancellous bone graft for ICRS-OCD stage III with lateral wall involvement have not been described in detail. Good bone union can be achieved with the lateral wall fragment of the capitellum by FFBP in combination with refreshing the sclerotic surface at the base of the lesion and cancellous bone grafting even in ICRS-OCD stage III lesions.

Methods

In total, 10 adolescent baseball players with a diagnosis of OCD, a median age of 13.5 years at the time of surgery, and 26.7 months of postoperative follow-up were included. Preoperative imaging showed that all patients had lesions in the late detached stage and of the lateral-widespread type based on the site of the focal lesion. The intraoperative ICRS-OCD classification was stage III. We aimed to preserve and fix the lateral wall fragment with cancellous bone grafting if the condition of the articular cartilage was good and the size and thickness of the segment could withstand fixation.

Results

Bone union of the lateral wall fragment was achieved in all cases. The elbow extension range of motion was −3.9° ± 9.7° before surgery and was eventually −0.4° ± 6.7° at the final assessment. Flexion range of motion ranged from 138.1° ± 10.5° to 142.4° ± 6.2°. The Timmerman and Andrews score significantly improved from 165.5 ± 10.9 points before surgery to 197.0 ± 6.3 points after surgery, demonstrating excellent results in all patients. All patients were able to return to competitive baseball.

Conclusion

The radiographic and clinical outcomes of FFBP for lateral wall fragments with cancellous bone graft were satisfactory, showing that the indications for this procedure could be extended to ICRS-OCD stage III.

Demographics and Epidemiology of Osteochondritis Dissecans of the Elbow Among Children and Adolescents

Background

Osteochondritis dissecans (OCD) of the elbow is a disorder of subchondral bone and articular cartilage, of which the incidence among children is not clearly known.

Purpose

To assess the demographics and epidemiology of OCD of the elbow among children.

Study Design

Cross-sectional study; Level of evidence, 3.

Methods

A retrospective chart review of an integrated health system for the years 2007 through 2011 was performed for patients with elbow OCD aged 2 to 19 years. Lesion location, laterality, and all patient demographics were recorded. OCD incidence was determined for the group as a whole as well as by sex and age group (2-5, 6-11, 12-19 years). Patient differences based on age, sex, and ethnicity were analyzed, and multivariable logistic regression models were used to assess the risk of elbow OCD by group.

Results

A total of 37 patients with 40 OCD lesions fit the inclusion criteria. No lesion was found among 2- to 5-year-olds. A majority of lesions (n = 39, 97.5%) were in the capitellum, and 1 (2.5%) was in the trochlea. Twenty-five patients (67.6%) had right-sided lesions; 9 (24.3%), left-sided; and 3 (8.1%), bilateral. The incidence of elbow OCD for patients aged 6 to 19 years was 2.2 per 100,000 overall and 3.8 and 0.6 per 100,000 for males and females, respectively. The majority of OCD cases were seen in those aged 12 to 19 years, with an incidence of 3.4 per 100,000 versus 0.38 among 6- to 11-year-olds. Multivariable logistic regression analysis revealed a 21.7-times increased odds ratio of elbow OCD among patients aged 12 to 19 years versus 6 to 11 years, and males had a 6.8-times greater odds ratio of elbow OCD than females (P < .0001 for both). Based on race and ethnicity, non-Hispanic whites had the highest incidence of elbow OCD as compared with all other ethnic groups.

Conclusion

In this population-based cohort study of pediatric elbow OCD, males had almost 7 times the risk of elbow OCD as compared with females, and 12- to 19-year-olds had nearly 22 times the risk of elbow OCD versus 6- to 11-year-olds. In keeping with many prior studies, the majority of patients had right-sided lesions.

Immunoelectron microscopic localization of Collagen type XV during human mesenchymal stem cells mineralization

Purpose/Aim of the study. Collagen type XV (ColXV) was identified, in our previews studies, as a novel component of bone extracellular matrix. The present study aims to investigate ColXV localization during mineralization of osteodifferentiated human mesenchymal stem cells (hMSCs).

MATERIAL AND METHODS

hMSCs cultured in osteogenic medium have been analyzed at day 14 and 28 for mineral matrix deposition by alizarin red S staining, ultrastructural analysis and ColXV localization by immunogold electron microscopy.

RESULTS

Our data show an intimate association between ColXV and fibrillar components in areas localized far from mineralized nodules.

CONCLUSIONS

We have demonstrated the efficacy of ultrastructural analysis, combined with immunocytochemistry, to establish a temporal and spatial localization of ColXV. This data, added to previous evidences, contribute to validate the negative effects of calcium deposits on ColXV expression.

Osteochondritis Dissecans: Etiology, Pathology, and Imaging with a Special Focus on the Knee Joint

This article is a review of the current understanding of the etiology, pathogenesis, and how to diagnose and treat knee osteochondritis dissecans (OCD) followed by an analysis of and outcomes of the treatments available. OCD is seen in children and adolescents with open growth plates (juvenile OCD) and adults with closed growth plates (adult OCD). The etiology of OCD lesions remains unclear and is characterized by an aseptic necrosis in the subchondral bone area. Mechanical factors seem to play an important role. Clinical symptoms are unspecific. Thus, imaging techniques are most important. Regarding treatment, a tremendous number of publications exist. Spontaneous healing is expected unless there is an unstable fragment, and treatment involves rest and different degrees of immobilization until healing. Patients with open physes and low-grade lesions have good results with conservative therapy. When surgery is necessary, the procedure depends on the stage and on the state of the cartilage. With intact cartilage, retrograde procedures are favorable. When the cartilage is damaged, several techniques can be used. While techniques such as drilling and microfracturing produce reparative cartilage, other techniques reconstruct the defect with additional osteochondral grafts or cell-based procedures such as chondrocyte transplantation. There is a tendency toward better results when using procedures that reconstruct the bone and the cartilage and there is also a trend toward better long-term results when comorbidities are treated. Severe grades of osteoarthrosis are rare.

Added Value of Preoperative Computed Tomography for Determining Cartilage Degeneration in Patients With Osteochondral Lesions of the Talar Dome

BACKGROUND

Osteochondral lesions of the talar dome (OLTs) involve the articular cartilage and subchondral bone. The subchondral bone plate (SBP) plays a crucial role in cartilage metabolism, and computed tomography (CT) can provide more precise information on subchondral bone. CT image prediction of the histological findings on OLT will be useful to determine the most appropriate therapeutic strategy.

PURPOSE

To evaluate the unique features of the CT findings that relate to the condition of the articular cartilage in OLT.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Thirty ankles in 29 patients who had OLT with an osteochondral fragment were retrospectively reviewed. At surgery, the osteochondral fragment of 19 ankles could be preserved (preservation group) by fixation or drilling, and in the remaining 11 ankles, the osteochondral fragment was removed (excision group). Preoperative CT findings were compared between the 2 groups. Biopsies of the osteochondral fragment from 13 ankles were performed. The relationship between the CT and histological findings were evaluated.

RESULTS

The area of lesion in the preservation group was significantly larger than that in the excision group. The CT images of the lesion showed the rate of absorption of the SBP in the preservation group to be lower than that in the excision group. As for the lesion bed absorption, it was higher in the preservation group than in the excision group. All cases in the excision group showed bed sclerosis, compared with 42.1% in the preservation group. The specimens with disruption of the SBP exhibited cartilage degeneration and abundant chondrocyte cloning. OLT with absorption of the SBP on CT showed severe cartilage degeneration, while the remaining SBP on CT showed low-grade cartilage degeneration.

CONCLUSION

This study shows the features of preoperative CT and histological findings in OLT with osteochondral fragments. The condition of the SBP affects the cartilage degeneration. CT findings provide important information for the determination of surgical treatment.

Focal Defects of the Knee Articular Surface: Evidence of a Regenerative Potential Pattern in Osteochondritis Dissecans and Degenerative Lesions

The surgical treatment of knee articular focal lesions may offer heterogeneous clinical results. Osteochondritis dissecans (OCD) lesions showed to heal better than degenerative lesions (DL) but the underlying biological reasons are unknown. We evaluated the basal histological and immunohistochemical characteristics of these lesions analyzing a series of osteochondral fragments from young patients with similar age but presenting different etiology. Osteochondral tissue samples were stained with Safranin O and graded using a histological score. Markers of mesenchymal progenitor cells (CD146), osteoclasts (tartrate-resistant acid phosphatase, TRAP), and vessels (CD34) were evaluated. Histological score showed a higher degeneration of both cartilage and bone compartments in OCD compared to DL fragments. Only CD146-positive cells were found at the same percentage in cartilage compartment of both DL and OCD patients. By contrast, in the bone compartment a significantly higher percentage of CD146, TRAP, and CD34 markers was found in OCD compared to DL patients. These data showed distinct histological characteristics of osteochondral focal lesions located in the same anatomical region but having a different etiology. The higher percentages of these markers in OCD than in DL, mainly associated with a high bone turnover, could help to explain the higher clinical healing potential of OCD patients.

Visualization of the Capitellum During Elbow Arthroscopy: A Comparison of 3 Portal Techniques

Background:

Capitellar osteochondritis dissecans (OCD) is a debilitating condition of unknown etiology for which various arthroscopic treatments are available. Prior data suggest that greater than 75% of the capitellum can be visualized arthroscopically through a dual lateral portal approach. However, there is no literature assessing arthroscopic visualization of the capitellum via alternative portals.

Purpose:

To determine the percentage of capitellum visualized using the dual lateral, distal ulnar and soft spot, and posterolateral and soft spot portal configurations in a cadaver model.

Study Design:

Descriptive laboratory study.

Methods:

Arthroscopy was performed on 12 fresh-frozen cadaver elbows, 4 for each of the following approaches: dual lateral, distal ulna, and posterolateral. Electrocautery was used to mark the most anterior, posterior, medial, and lateral points seen on the capitellum. The radiocapitellar joint was subsequently exposed through an extensile posterior dissection, and the surface anatomy was reconstructed using the Microscribe 3D digitizing system. Using Rhinoceros software, the percentage of capitellum surface area visualized by each approach was determined.

Results:

The mean percentage of capitellum visualized for the dual lateral, distal ulna, and posterolateral approaches was approximately 68.8%, 66.3%, and 63.5%, respectively. There was no significant difference between the percentage of capitellum seen among approaches (P = .68). On average, 66.5% of the capitellum was visible through these 3 arthroscopic approaches to the elbow.

Conclusion:

Approximately 66.5% of the capitellum is visualized through the popularized posterior arthroscopic portals, with no significant differences found between the 3 investigated approaches.

Clinical Relevance:

As determined in this cadaveric model investigation, each portal technique provides equivalent visualization for capitellar OCD pathology.

Return to Play After Osteochondral Autograft Transplantation of the Capitellum: A Systematic Review

PURPOSE

To determine the rate of return to play and to identify lesion or osteochondral graft characteristics that may influence the return to competitive athletics after osteochondral autograft transplantation (OAT) for symptomatic osteochondritis dissecans (OCD) lesions.

METHODS

A systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. A duplicate search of PubMed, Embase, Scopus, Web of Science, and CENTRAL databases was performed, beginning from the database inception dates through July 2016, for all articles evaluating the return to play after OAT for OCD lesions of the capitellum. A methodological quality assessment was completed for all included studies. Patient demographics, osteochondral lesion and graft characteristics, the number of patients, and timing of return to competitive activity were collected and evaluated. Association between graft size/number, the time to osseous healing, and return to sport was evaluated.

RESULTS

Seven articles met the inclusion criteria. All included studies were case series of moderate quality with a mean Methodological Index for Non-Randomized Studies score of 12/16. Overall, 94% (119/126) of patients undergoing OAT for OCD lesions of the capitellum successfully returned to competitive sports. The mean reported time for unrestricted return to athletic competition after OAT was 5.6 months (range, 3-14 months).

CONCLUSIONS

Current best evidence suggests that OAT is successful in treating advanced OCD lesions of the capitellum and returning athletes to high-level competition. Evidence supporting the association between the size and number of grafts used and the time to osseous healing and return to sport is currently limited. Our assessment of the time to return to athletic competition was limited because of variable surgical technique, postoperative rehabilitation protocols, and outcome assessment.

LEVEL OF EVIDENCE

Level IV, systematic review of Level IV studies.

Osteochondritis Dissecans of the Capitellum: A Case Report of Successful Arthroscopic Treatment

Introduction. Osteochondritis dissecans (OCD) of the capitellum is a localized disorder of the subchondral bone, in a region with limited healing capacity. Although its aetiology is still unknown, it has been associated with repetitive microtrauma. The natural history of this disease involves the evolution for degenerative joint disease in approximately half of the patients, with early identification and treatment being critical to optimizing the outcome. Case Presentation. We present a rare case in our practice, illustrating a capitellar OCD in a fifteen-year-old White male without an identified cause of repetitive microtrauma. Conclusion. In this case prompt diagnosis and arthroscopic-assisted treatment led to a successful result.

Current Concepts: Osteochondritis Dissecans of the Capitellum and the Role of Osteochondral Autograft Transplantation

Background: Osteochondritis dissecans (OCD) of the capitellum is a painful condition, which often affects young throwing athletes. Our current understanding regarding the etiology, risks factors, diagnosis, and efficacy of the available treatment options has expanded over recent years, however remains suboptimal. Recent data on patient-reported outcomes following osteochondral autograft transplantation (OAT) for the treatment of large osteochondral lesions of the capitellum have been promising but limited. This review seeks to critically analyze and summarize the available literature on the etiology, diagnosis, and reported outcomes associated with OCD of the capitellum and the use of OAT for its treatment. Methods: A comprehensive literature search was conducted. Unique and customized search strategies were formulated in PubMed, Embase, Scopus, Web of Science, and CENTRAL. Combinations of keywords and controlled vocabulary terms were utilized in order to cast a broad net. Relevant clinical, biomechanical, anatomic and imaging studies were reviewed along with recent review articles, and case series. Results: Forty-three articles from our initial literature search were found to be relevant for this review. The majority of these articles were either review articles, clinical studies, anatomic or imaging studies or biomechanical studies. Conclusions: Current evidence suggests that OAT may lead to better and more consistent outcomes than previously described methods for treating large OCD lesions of the capitellum.

Results of Bone Peg Grafting for Capitellar Osteochondritis Dissecans in Adolescent Baseball Players

BACKGROUND

Bone peg grafting (BPG) has been advocated for early-stage humeral capitellar osteochondritis dissecans (COCD). However, the clinical and radiological results of BPG, along with its indications, have not been described in detail.

HYPOTHESIS

COCD classified as International Cartilage Repair Society (ICRS) osteochondritis dissecans (OCD) I or II in adolescent baseball players can be treated successfully by BPG.

STUDY DESIGN

Case series; Level of evidence, 4 METHODS: Eleven male baseball players (age range at surgery, 13-16 years) who underwent BPG for COCD were enrolled in this study. No improvement had been seen in any patient after 6 months of preoperative nonthrowing observation. During surgery, 2 to 5 bone pegs were inserted into the COCD lesion after confirmation of lesion stability to the bony floor. All patients were directly evaluated at 12 and 24 months after surgery by physical findings, radiological prognosis, and magnetic resonance imaging (MRI).

RESULTS

Of the 11 patients, 10 could return to comparable baseball ability levels within 12 months. The Timmerman-Andrews score improved significantly from a mean ± SD of 171.8 ± 12.1 preoperatively to 192.3 ± 6.5 at the final observation. Radiological healing of the lesions was determined as complete in 8 patients and partial in 3. Patients possessing a centrally positioned lesion or a lesion <75% of the size of the capitellum tended most strongly to achieve complete radiological healing, while growth plate status appeared unrelated to outcome. The mean Henderson MRI score improved from 6.3 ± 1.5 to 4.8 ± 1.6 at 12 and 24 months after BPG, respectively. MRI findings also suggested that remodeling of COCD lesions had continued to up to 24 months postoperatively.

CONCLUSION

BPG enabled 91% of COCD patients with ICRS OCD I or II to return to preoperative baseball abilities within 12 months. Integration of the grafted site may continue until at least 24 months postoperatively. An ICRS OCD I or II lesion with central positioning and/or occupying <75% of the size of the capitellum in the coronal plane is a good indication for BPG.

Return to Sport After Operative Management of Osteochondritis Dissecans of the Capitellum: A Systematic Review and Meta-analysis

BACKGROUND

Capitellar osteochondritis dissecans (OCD) is commonly managed surgically in symptomatic adolesent throwers and gymnasts. Little is known about the impact that surgical technique has on return to sport.

PURPOSE

To evaluate the clinical outcomes and return-to-sport rates after operative management of OCD lesions in adolescent athletes.

STUDY DESIGN

Systematic review; Level of evidence, 4.

METHODS

The PubMed, CINAHL, EMBASE, SPORTDiscus (EBSCO), and Cochrane Central Register of Controlled Trials databases were queried for studies evaluating outcomes and return to sport after surgical management of OCD of the capitellum. Two independent reviewers conducted a systematic review according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Studies reporting patient outcomes with return-to-sport data and minimum 6-month follow-up were included in the review.

RESULTS

After review, 24 studies reporting outcomes in 492 patients (mean age ± SD, 14.3 ± 0.9 years) were analyzed. The overall return-to-sport rate was 86% at a mean 5.6 months. Return to the highest preoperative level of sport was most common after osteochondral autograft procedures (94%) compared with debridement and marrow stimulation procedures (71%) or OCD fixation surgery (64%). Elbow range of motion improved by 15.9° after surgery. The Timmerman-Andrews subjective and objective scores significantly improved after surgery. Complications were low (<5%), with 2 cases of donor site morbidity after osteoarticular autograft transfer (OAT) autograft harvest. The most common indications for reoperation were repeat debridement/loose body removal.

CONCLUSION

A high rate of return to sport was observed after operative management of capitellar OCD. Patients were more likely to return to their highest level of preoperative sport after OAT autograft compared with debridement or fixation. Significant improvements in elbow range of motion and patient outcomes are seen with low complication rates after OCD surgery.

An Update on the Pathogenesis of Osteochondrosis

Osteochondrosis is defined as a focal disturbance in endochondral ossification. The cartilage superficial to an osteochondrosis lesion can fracture, giving rise to fragments in joints known as osteochondrosis dissecans (OCD). In pigs and horses, it has been confirmed that the disturbance in ossification is the result of failure of the blood supply to epiphyseal growth cartilage and associated ischemic chondronecrosis. The earliest lesion following vascular failure is an area of ischemic chondronecrosis at an intermediate depth of the growth cartilage (osteochondrosis latens) that is detectable ex vivo, indirectly using contrast-enhanced micro- and conventional computed tomography (CT) or directly using adiabatic T1ρ magnetic resonance imaging. More chronic lesions of ischemic chondronecrosis within the ossification front (osteochondrosis manifesta) are detectable by the same techniques and have also been followed longitudinally in pigs using plain CT. The results confirm that lesions sometimes undergo spontaneous resolution, and in combination, CT and histology observations indicate that this occurs by filling of radiolucent defects with bone from separate centers of endochondral ossification that form superficial to lesions and by phagocytosis and intramembranous ossification of granulation tissue that forms deep to lesions. Research is currently aimed at discovering the cause of the vascular failure in osteochondrosis, and studies of spontaneous lesions suggest that failure is associated with the process of incorporating blood vessels into the advancing ossification front during growth. Experimental studies also show that bacteremia can lead to vascular occlusion. Future challenges are to differentiate between causes of vascular failure and to discover the nature of the heritable predisposition for osteochondrosis.

Arthroscopic fragment fixation using hydroxyapatite/poly-L-lactate Acid thread pins for treating elbow osteochondritis dissecans

BACKGROUND

Various procedures, such as arthroscopic debridement, osteochondral transplantation, and bone plug fixation, have been described for the treatment of osteochondritis dissecans (OCD) of the humeral capitellum. However, the use of hydroxyapatite/poly-L-lactate acid (HA/PLLA) thread pins to fix the osteochondral fragment in an OCD lesion is a recent development.

HYPOTHESIS

Adolescent throwing athletes would return to preinjury levels of function after arthroscopic osteochondral fragment fixation using HA/PLLA thread pins.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Enrolled in this prospective cohort study were 18 adolescent baseball players (mean age, 14.2 years; range 12-16, years) with elbow OCD who underwent arthroscopic fragment fixation with HA/PLLA thread pins between 2006 and 2009. All patients were affected on their dominant side. Plain radiographs taken before surgery showed an open physis in 13 patients (72%) and a closed physis in 5 patients (28%). During surgery, the condition of the OCD lesion was evaluated by use of the International Cartilage Research Society (ICRS) classification system; there were 5 grade II, 11 grade III, and 2 grade IV cases. Outcomes were assessed after 3 years (mean, 39 months; range, 36-50 months). Elbow function was measured using the Timmerman and Andrews score and the Mayo Elbow Performance Index. Return to sports activity was assessed as higher than preinjury, same level, lower level, or no return to sports.

RESULTS

The mean Timmerman and Andrews score improved significantly from 126.6±6.5 to 197.5±1.5, and the mean Mayo Elbow Performance Index improved significantly from 68.0±2.1 to 98.06±0.9 (P=.0001 for both). Mean elbow extension improved significantly from -10°±10.4° to -0.8°±5.2° (P=.006), and mean flexion improved significantly from 123.1°±17.9° to 138.6°±6.1° (P=.001). Three patients had a loss of extension greater than 5°. Five patients returned to a higher level of sports activity, 10 patients returned to the same level, and 2 patients returned to a lower level. A remaining patient did not return to baseball. In one patient, the lesion did not heal, resulting in fragmentation at 1 year after surgery. This patient consequently underwent revision arthroscopy to remove the lesion, and he eventually returned to sports at the same level of activity.

CONCLUSION

Arthroscopic fragment fixation using HA/PLLA thread pins provides a beneficial clinical outcome to adolescent baseball players with humeral capitellar OCD.

Histological evaluation of low-intensity pulsed ultrasound on osteochondritis dissecans of the humeral capitellum

Background

The clinical use of low-intensity pulsed ultrasound (LIPUS) was recently evaluated in cases of osteochondritis dissecans of the humeral capitellum (elbow OCD). However, the mechanism underlying the effect of LIPUS in elbow OCD is not well understood. The aim of this study was to histopathologically evaluate the effect of LIPUS irradiation on elbow OCD.

Methods

Fifteen patients with elbow OCD were enrolled in this study. All patients were juvenile baseball players (average age, 13.1 years). LIPUS was performed under the same conditions as the fracture treatment for an average length of 15.1 days in the preoperative period in seven patients (LIPUS group). Cylindrical tissue specimens obtained at the time of surgery were stained with hematoxylin and eosin and alcian blue, and were also immunostained to detect type 1 collagen (Col-1), osteopontin (OPN), and Runx2. The state of the cartilage and subchondral bone and expression levels of Col-1, OPN, and Runx2 were evaluated with a semiquantitative grading system by a blinded pathologist. Histological and immunohistological findings in both groups were compared using Fisher's exact test.

Results

Both groups showed reparative tissue and cartilaginous metaplasia at the separation level near the subchondral bone; Col-1 was expressed in the reparative tissue. Furthermore, OPN and Runx2 were expressed in the interstitial cells near the separation level. The cartilage and subchondral bone findings in histological evaluations did not differ significantly between the LIPUS and control groups. The distribution of OPN expression levels in the two groups was as follows: Grade 0-LIPUS group, zero patients, and control group, five patients; Grade 1-LIPUS group and control group, two patients each; Grade 2-LIPUS group, five patients and control group, one patient; Grade 3-LIPUS group, one patient and control group, zero patients. OPN expression was significantly higher in the LIPUS group than in the control group (p = 0.04).

Conclusion

LIPUS stimulation increased the expression levels of OPN in elbow OCD.

Osteochondral lesion of the bilateral femoral heads in a young athletic patient

Osteochondral lesions of the femoral head are uncommon and few studies have reported their imaging findings. Since joints are at risk of early degeneration after osteochondral damage, timely recognition is important. Osteochondral lesions of femoral head may often be necessary to differentiate from avascular necrosis. Here, we report a case of osteochondral lesions on bilateral femoral heads. This lesion manifested as subchondral cysts in initial radiographs, which led to further evaluation by computed tomography arthrography and magnetic resonance imaging, which revealed overlying cartilage defects.

Osteochondritis Dissecans of the Humeral Capitellum: The Significance of Lesion Location

Background:

There is a paucity of information regarding the effect of lesion location on surgical outcomes in the treatment of osteochondritis dissecans (OCD) of the humeral capitellum.

Purpose:

To survey the literature for conclusions that can be drawn regarding the effect of lesion location on treatment of capitellar OCD lesion. The hypothesis was that lesion severity and the need for more aggressive surgical interventions are increased for lesions that are located laterally on the capitellum.

Study Design:

Systematic review; Level of evidence, 4.

Methods:

All studies from the past 20 years were determined using a literature search of PubMed, Scopus, and Cochrane databases. Included studies were clinical studies that specifically commented on the location of the OCD defect on the capitellum. Excluded studies were case reports, review articles, and those that did not include information regarding the location of the OCD lesion on the capitellum.

Results:

Six studies met the inclusion criteria. Autograft reconstruction was found to yield reliable outcomes regardless of lesion location, as 87% (26/30) of lateral lesions had excellent or good outcomes using the Timmerman and Andrews score, while 91% (21/23) of central lesions had excellent or good outcomes. There was a trend toward improved outcomes with more aggressive surgical management of lateral lesions, specifically those involving the lateral cartilage margin. The failure rate for nonreconstructive operative management for lateral lesions was noted to be significant, as failure rates for peg fixation of lateral lesions was seen to be as high as 44% (4/9) in one of the studies.

Conclusion:

Studies regarding capitellar OCD lesion location, as it relates to symptom severity and surgical outcome, are limited. The literature suggests that lesions located on the lateral capitellum—particularly those involving the lateral cartilage margin—require more aggressive surgical management than those located medially. A refinement of the Takahara classification is proposed, which includes lesion location as a factor influencing surgical decision making.

Operative management of ulnar collateral ligament insufficiency in adolescent athletes

BACKGROUND

The incidence of ulnar collateral ligament (UCL) injuries of the elbow has increased in adolescents over the past decade because of widespread participation in athletics and heightened awareness among physicians.

HYPOTHESIS

Ulnar collateral ligament reconstruction using the docking technique would result in a successful return to athletic activity in this age group.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Study participants were 55 skeletally mature adolescent athletes (mean age, 17.6 years; range, 15-18 years) who underwent UCL reconstruction between 2008 and 2010. While the majority of patients were baseball players (n = 47), there were 3 gymnasts and 5 javelin throwers included in the study. Each patient underwent UCL reconstruction utilizing the docking technique after an adequate trial of nonoperative management (mean, 5.8 months). At the latest follow-up, patients were evaluated to determine their ability to return to athletic activity. Clinical outcomes were classified using the Conway scale, the Andrews-Timmerman score, and the Kerlan-Jobe Orthopaedic Clinic (KJOC) score.

RESULTS

At a minimum 2-year follow-up, 87% (48/55) of patients had excellent results using the Conway scale. Overall, there were only 2 poor results (3.6%) that were observed in patients with concomitant osteochondritis dissecans lesions of the capitellum. There were 4 postoperative complications in 4 patients (2 gymnasts and 2 javelin throwers) who developed ulnar neuritis after UCL reconstruction. The mean Andrews-Timmerman score was 83.6 ± 7.2 (range, 30-100), and the mean KJOC score was 88.0 ± 6.0 (range, 40-100).

CONCLUSION

The docking technique results in favorable clinical outcomes in adolescent athletes with UCL insufficiency at a minimum of 2 years postoperatively. Patients with concomitant intra-articular lesions should be cautioned preoperatively that they might experience inferior clinical outcomes. Postoperatively, adolescent gymnasts and javelin throwers may be at an increased risk for transient paresthesia of the ulnar nerve caused by increased stress on the medial elbow.

Transection of vessels in epiphyseal cartilage canals leads to osteochondrosis and osteochondrosis dissecans in the femoro-patellar joint of foals; a potential model of juvenile osteochondritis dissecans

OBJECTIVE

To transect blood vessels within epiphyseal cartilage canals and observe whether this resulted in ischaemic chondronecrosis, an associated focal delay in enchondral ossification [osteochondrosis (OC)] and pathological cartilage fracture [osteochondrosis dissecans (OCD)] in the distal femur of foals, with potential translational value to the pathogenesis of juvenile osteochondritis dissecans (JOCD) in children.

METHOD

Ten Norwegian Fjord Pony foals were operated at the age of 13-15 days. Two vessels supplying the epiphyseal growth cartilage of the lateral trochlear ridge of the left distal femur were transected in each foal. Follow-up examination was carried out from 1 to 49 days post-operatively and included plain radiography, macroscopic and histological examination.

RESULTS

Transection of blood vessels within epiphyseal cartilage canals resulted in necrosis of vessels and chondrocytes, i.e., ischaemic chondronecrosis, in foals. Areas of ischaemic chondronecrosis were associated with a focal delay in enchondral ossification (OC) in foals examined 21 days or more after transection, and pathological cartilage fracture (OCD) in one foal examined 42 days after transection.

CONCLUSION

The ischaemic hypothesis for the pathogenesis of OC has been reproduced experimentally in foals. There are several similarities between OCD in animals and JOCD in children. It should be investigated whether JOCD also occurs due to a focal failure in the cartilage canal blood supply, followed by ischaemic chondronecrosis.

Osteochondral transplantation in the elbow leads to good clinical and radiologic long-term results: an 8- to 14-year follow-up examination

BACKGROUND

In the long-term follow-up after debridement, microfracture, or drilling of osteochondral lesions in the elbow, subsequent osteoarthritis is a problem. Osteochondral transplantation for these defects has become a more common procedure. However, long-term results are unknown.

PURPOSE

This study was undertaken to evaluate long-term clinical and radiologic outcomes of advanced osteochondral lesions in the elbow treated with osteochondral transplantation.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

The study included 8 patients with osteochondral lesions in the elbow who were treated by autologous osteochondral transplantation between 1996 and 2002. Patients (average age, 17 years) were evaluated pre- and postoperatively by Broberg-Morrey score to assess elbow function and by American Shoulder and Elbow Surgeons (ASES) score for pain analysis. In addition, radiographs (at the first postoperative day, and at 5-year and 10-year follow-up) and magnetic resonance images (8 to 12 weeks postoperatively, and at 5-year and 10-year follow-up) were made to evaluate the joint status. At last follow-up (range, 8-14 years postoperatively), 7 of 8 patients were seen for clinical examination and radiologic analysis.

RESULTS

The Broberg-Morrey score increased from an average of 75.9 ± 13.1 to 96.4 ± 2.4 and ASES score significantly improved as follows: worst pain, 7.9 ± 1.1 to 1.6 ± 1.9; rest pain, 3.14 ± 2.7 to 0.6 ± 1.5; weight-lifting pain, 7.6 ± 0.8 to 3.1 ± 1.6; and repetitive movement pain, 5.3 ± 2.4 to 1.6 ± 1.5. Compared with the contralateral side, there was a mean preoperative flexion lag of 12.5° ± 11.6°. At the final follow-up, flexion was free. The mean extension lag was reduced from average 5.4° ± 5.7° to 0°. Radiographs of 2 patients made at final follow-up showed mild signs of osteoarthritis (Kellgren and Lawrence grade I). Postoperative magnetic resonance images showed graft viability in all and a congruent chondral surface in 6 of 7 patients.

CONCLUSION

Clinical long-term results after osteochondral transplantation in the elbow are good to excellent and comparable with midterm results in the literature. Therefore, this technique is a reliable option for satisfactory long-term results regarding treatment of advanced osteochondral lesions in the elbow.

Osteochondritis dissecans of the capitellum: minimum 1-year follow-up after arthroscopic debridement

PURPOSE

The purpose of our study is to show that arthroscopic debridement is an appropriate intervention for midterm to long-term subjective symptom relief of osteochondritis dissecans (OCD) of the elbow.

METHODS

A retrospective case series of 13 patients undergoing arthroscopic treatment of OCD of the elbow over a 10-year period was studied. Patients were assessed with a mean follow-up of 3.6 years (range, 12 months to 8 years). The disability/symptom section of the Disabilities of the Arm, Shoulder and Hand (DASH) was used to measure patient-reported outcome. Additional questions were used to assess other injuries to the elbow and return to sports activities.

RESULTS

Of 13 patients, 8 reported participating in repetitive valgus stress sports associated with overhead throwing. Two participated in gymnastics. Ten patients provided follow-up data greater than 1 year after surgical intervention. The mean follow-up DASH score for surgically treated patients was 8.6 (range, 0.0 to 22.41). Four patients reported a complete return to their sports activities, and six reported complete cessation of at least 1 sport. By use of intraoperative reports, the OCD lesions were graded according to the Classification System for OCD Lesions established by the American Sports Medicine Institute. No difference in mean DASH score between grades was found.

CONCLUSIONS

In our small group of patients, arthroscopic debridement of OCD of the capitellum resulted in a functional elbow with subjective symptom relief for the majority of patients, as evidenced by DASH scores. However, despite a functional outcome, many patients reported ceasing at least some sporting activities because of their elbow.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

Osteochondritis dissecans of the capitellum: current concepts

Osteochondritis dissecans (OCD) of the capitellum is an uncommon disorder seen primarily in the adolescent overhead athlete. Unlike Panner disease, a self-limiting condition of the immature capitellum, OCD is multifactorial and likely results from microtrauma in the setting of cartilage mismatch and vascular susceptibility. The natural history of OCD is poorly understood, and degenerative joint disease may develop over time. Multiple modalities aid in diagnosis, including radiography, MRI, and magnetic resonance arthrography. Lesion size, location, and grade determine management, which should attempt to address subchondral bone loss and articular cartilage damage. Early, stable lesions are managed with rest. Surgery should be considered for unstable lesions. Most investigators advocate arthroscopic débridement with marrow stimulation. Fragment fixation and bone grafting also have provided good short-term results, but concerns persist regarding the healing potential of advanced lesions. Osteochondral autograft transplantation appears to be promising and should be reserved for larger, higher grade lesions. Clinical outcomes and return to sport are variable. Longer-term follow-up studies are necessary to fully assess surgical management, and patients must be counseled appropriately.

Osteochondritis dissecans of the capitellum

Osteochondritis dissecans of the capitellum is a well-recognized cause of elbow pain and disability in the adolescent athlete. This condition typically affects young athletes, such as throwers and gymnasts, involved in high-demand, repetitive overhead, or weightbearing activities. The true cause, natural history, and optimal treatment of osteochondritis dissecans of the capitellum remain unknown. Suspicion of this condition warrants investigation with proper radiographs and magnetic resonance imaging. Prompt recognition of this disorder and institution of nonoperative treatment for early, stable lesions can result in healing with later resumption of sporting activities. Patients with unstable lesions or those failing nonoperative therapy require operative intervention with treatment based on lesion size and extent. Historically, surgical treatment included arthrotomy with loose body removal and curettage of the residual osteochondral defect base. The introduction of elbow arthroscopy in the treatment of osteochondritis dissecans of the capitellum permits a thorough lesion assessment and evaluation of the entire elbow joint with the ability to treat the lesion and coexistent pathology in a minimally invasive fashion. Unfortunately, the prognosis for advanced lesions remains more guarded, but short-term results after newer reconstruction techniques are promising.

Passage-affected competitive regulation of osteoprotegerin synthesis and the receptor activator of nuclear factor-kappaB ligand mRNA expression in normal human osteoblasts stimulated by the application of cyclic tensile strain

Mechanical stress application is a unique method for bone studies. We have reported regulation via the p38 mitogen-activated protein kinase (MAPK) pathway in osteoblasts under application of cyclic tensile strain (CTS), among many reports on the extracellular signal-regulated kinase (ERK) 1/2 pathway during mechanical stress, and questions remain as to the differences between our findings and those of others regarding types of MAPK activation. In the present study, osteoblasts were used after the third passage and stimulated by the application of 7%, 0.25 Hz CTS for 3 days, 4 h/day. CTS-induced osteoprotegerin (OPG) synthesis in osteoblasts increased at the third passage and decreased at the fifth passage, whereas CTS-induced receptor activator of nuclear factor-kappaB ligand (RANKL) mRNA expression decreased in osteoblasts at the third passage and increased at the fifth passage. Increases in CTS-induced osteopontin (OPN) synthesis, cyclooxygenase-2 (Cox-2) mRNA expression, and nitric oxide (NO) production by osteoblasts did not change at the third and fifth passages. Furthermore, p38 MAPK at the third passage and ERK1/2 at the fifth passage were found to be competitively activated in osteoblasts by the application of CTS. Based on these results, osteoblasts were shown to be affected by the number of passages. It was suggested that the examination of passage-affected characteristics of osteoblasts might not only be pertinent to the analysis of cellular senescence and in vivo models of bone remodelling with aging but could also be useful in the development of bone tissue engineering.