Topographic Analysis of 2 Alternative Donor Sites of the Ipsilateral Elbow in the Treatment of Capitellar Osteochondritis Dissecans

Interobserver reliability of the classification of capitellar osteochondritis dissecans using magnetic resonance imaging

AIM

(1) To determine the interobserver reliability of magnetic resonance classifications and lesion instability criteria for capitellar osteochondritis dissecans lesions and (2) to assess differences in reliability between subgroups.

METHODS

Magnetic resonance images of 20 patients with capitellar osteochondritis dissecans were reviewed by 33 observers, 18 orthopaedic surgeons and 15 musculoskeletal radiologists. Observers were asked to classify the osteochondritis dissecans according to classifications developed by Hepple, Dipaola/Nelson, Itsubo, as well as to apply the lesion instability criteria of DeSmet/Kijowski and Satake. Interobserver agreement was calculated using the multirater kappa (k) coefficient.

RESULTS

Interobserver agreement ranged from slight to fair: Hepple (k = 0.23); Dipaola/Nelson (k = 0.19); Itsubo (k = 0.18); DeSmet/Kijowksi (k = 0.16); Satake (k = 0.12). When classifications/instability criteria were dichotomized into either a stable or unstable osteochondritis dissecans, there was more agreement for Hepple (k = 0.52; p = .002), Dipaola/Nelson (k = 0.38; p = .015), DeSmet/Kijowski (k = 0.42; p = .001) and Satake (k = 0.41; p < .001). Overall, agreement was not associated with the number of years in practice or the number of osteochondritis dissecans cases encountered per year (p > .05).

CONCLUSION

One should be cautious when assigning grades using magnetic resonance classifications for capitellar osteochondritis dissecans. When making treatment decisions, one should rather use relatively simple distinctions (e.g. stable versus unstable osteochondritis dissecans; lateral wall intact versus not intact), as these are more reliable.

Editorial Commentary: "Elbow-to-Elbow" Capitellar Osteochondral Autologous Transplantation for Osteochondritis Dissecans-Are We Closer to the Holy Grail of Osteochondral Graft?

The knee or rib has been used routinely as a donor site for capitellar osteochondral autologous transplantation (osteoarticular transplantation) procedures with promising results. However, donor-site morbidity is a bitter truth that has led surgeons to pursue alternatives to the ipsilateral elbow. The non-articulating radial head and the lateral olecranon tip show acceptable topography and histology. However, size limitations require additional and clinical study.

Histologic Analysis of 2 Alternative Donor Sites of the Ipsilateral Elbow in the Treatment of Capitellar Osteochondritis Dissecans

PURPOSE

To compare the histologic features of the cartilage from the capitellum with 2 proposed alternative donor sites from the ipsilateral elbow in the treatment of capitellar osteochondritis dissecans (OCD): the nonarticulating part of the radial head and the nonarticulating lateral side of the olecranon tip.

METHODS

Ten human cadaveric elbow specimens with macroscopically normal articular surfaces were used to obtain 5-mm osteochondral grafts: 10 from the capitellum (60° anteriorly relative to the humeral shaft), 10 from the radial head (nonarticulating part at 80°), and 4 from the olecranon (lateral side of the olecranon tip). Grafts were fixated in formalin (4% formaldehyde), decalcified, and processed into standard 8-μm-thick hematoxylin and eosin-and Toluidine Blue-stained sections. These were assessed for cartilage thickness, shape of articular surface, and 13 histologic parameters of the International Cartilage Repair Society II. Olecranon scores were excluded from statistical analysis.

RESULTS

Mean cartilage thickness was 1.5 ± 0.22 mm at the capitellum; 1.3 ± 0.34 mm at the radial head; and 1.9 ± 1.0 mm at the olecranon. There was no difference in cartilage thickness between the capitellum and radial head (P = .062). All grafts demonstrated a convex articular surface. International Cartilage Repair Society II scores ranged from 82 to 100 for the capitellum, from 81 to 100 for the radial head, and from 67 to 87 for the olecranon tip. There was less chondrocyte clustering at the capitellum (84 ± 14) than in the radial head (94 ± 3.2; P = .019). Mid/deep zone assessment of the capitellum scored higher (97 ± 6.7) than the radial head (91 ± 4.6; P = .038).

CONCLUSIONS

This study demonstrates appropriate histologic similarities between the cartilage from the capitellum and 2 alternative donor sites of the ipsilateral elbow in the treatment of capitellar OCD: the nonarticulating part of the radial head and the nonarticulating lateral side of the olecranon tip.

CLINICAL RELEVANCE

From an histologic point of view, there seem to be no obstacles to use grafts from these alternative donor sites for reconstruction of the capitellum when performing osteochondral autologous transplantation.

Decreased Defect Size and Partial Restoration of Subchondral Bone on Computed Tomography After Arthroscopic Debridement and Microfracture for Osteochondritis Dissecans of the Capitellum

BACKGROUND

Arthroscopic debridement and microfracture are considered the primary surgical treatment for capitellar osteochondritis dissecans (OCD). Healing of the subchondral bone plays an essential role in cartilage repair, while lack of healing is related to the development of osteoarthritis. To date, it is unknown to what extent healing of the subchondral bone occurs after this technique in the elbow.

PURPOSE

To analyze defect size changes and subchondral bone healing with computed tomography (CT) after arthroscopic debridement and microfracture for advanced capitellar OCD.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Between 2009 and 2016, 67 patients underwent arthroscopic debridement and microfracture for advanced capitellar OCD. Fifty-four patients (81% follow-up rate) with CT scans were included (mean ± SD: preoperative, 4.0 ± 1.7 months; postoperative, 29 ± 9.0 months). OCD defect size was assessed by measuring the largest diameter in 3 directions: medial-lateral direction (coronal plane) and anterior-posterior direction and depth (both in sagittal plane). Healing of the OCD was divided into 3 categories: good-complete osseous union or ossification; fair-incomplete osseous union or ossification but improved; poor-no changes between pre- and postoperative scans. Postoperative clinical outcome was assessed with the Oxford Elbow Score (OES) at the same time as the postoperative CT scan.

RESULTS

There were 30 female and 24 male patients (age, 15.7 ± 3.2 years). Defect size decreased ( P < .001) in all 3 directions (medial-lateral × anterior-posterior × depth) at 29 ± 9.0 months: preoperatively, 7.9 ± 2.8 × 8.0 ± 3.2 × 4.1 ± 1.5 mm; postoperatively, 3.5 ± 3.3 × 4.0 ± 3.5 × 1.6 ± 1.4 mm. Healing of the subchondral bone was graded as good in 19 defects (35%), fair in 27 (50%), and poor in 8 (15%). The mean postoperative OES score was 40 ± 8.4. Neither postoperative defect size nor healing grade correlated with the OES ( P > .05).

CONCLUSION

Arthroscopic debridement and microfracture for advanced capitellar OCD result in improved (ie, decreased) defect size at a mean follow-up of 29 months, both in width and in depth. Healing of the subchondral bone was either good or fair in 85%. Interestingly, CT findings did not correlate with clinical outcomes.

Editorial Commentary: Is the Cure Worse Than the Disease? Harvesting Autologous Osteochondral Transfer Plugs for Treatment of Lesions of the Elbow

For autologous osteochondral transfer procedures for osteochondritis dessicans of the elbow, surgeons usually use the knee or ribs as donor sites. This procedure is not without donor site complications. Finding local donor sites is important to reducing the overall morbidity of this procedure.