Osteochondral lesions of the capitellum do not affect elbow kinematics and stability with intact collateral ligaments: an in vitro biomechanical study

Radiocapitellar Contact Characteristics After Osteochondral Defect Repair Using a Novel Hybrid Reconstructive Procedure

Background:

Many procedures to reconstruct osteochondral defects of the elbow radiocapitellar (RC) joint lack versatility or durability or do not directly address the subchondral bone structure and function.

Purpose/Hypothesis:

To biomechanically characterize the RC joint contact area, force, pressure, and peak pressure before and after reconstruction of osteochondral defects using a novel hybrid reconstructive procedure. It was hypothesized that the procedure would restore the contact characteristics to the intact condition.

Study Design:

Controlled laboratory study.

Methods:

A total of 10 cadaveric elbows (mean age 67 ± 2.7 years) were dissected to isolate the humerus and radial head. RC contact area, contact force, mean contact pressure, and peak contact pressure were measured with the elbow at 45° of flexion and neutral forearm rotation at compressive loads of 25, 50, and 75 N. Osteochondral defects 8 and 11 mm in diameter were created at the center of the capitellum; the defects were then reconstructed with a titanium fenestrated threaded implant, countersunk in the subchondral bone, with an acellular dermal matrix allograft sutured in place on top of the implant. Five conditions (intact, 8-mm defect, 8-mm repair, 11-mm defect, and 11-mm repair) were tested and results were compared using repeated-measures analysis of variance.

Results:

Both 8- and 11-mm defects significantly increased RC mean contact pressure at all compressive loads (P ≤ .008) and significantly increased peak contact pressure at compressive loads of 50 and 75 N (P < .002) compared with the intact condition. Repair of the 8-mm defect significantly decreased RC mean contact pressure at 25- and 50-N loads (P ≤ .009) and significantly decreased peak contact pressure at 50- and 75-N loads (P ≤ .035) compared with the defect condition. Repair of the 11-mm defect decreased mean contact pressure significantly at all compressive loads (P ≤ .001) and peak contact pressure at 50- and 75-N loads (P < .044) compared with the defect condition.

Conclusion:

RC joint contact pressure was restored to intact conditions while avoiding increased peak contact pressure or edge loading after repairing osteochondral defects related to osteochondrosis with a novel hybrid reconstruction technique.

Clinical Relevance:

This hybrid procedure that addresses the entire osteochondral unit may provide a new treatment option for osteochondral defects.

Prevalence of Capitellar Osteochondritis Dissecans in Children With Chronic Radial Head Subluxation and Dislocation

OBJECTIVE

An abnormal radiocapitellar articulation may play a role in the development of capitellar osteochondritis dissecans (OCD). The objective of this study is to determine the prevalence of capitellar OCD in pediatric patients with chronic radial head subluxation (RHS) or radial head dislocation (RHD).

MATERIALS AND METHODS

We searched the radiology reports generated at a large pediatric hospital between 2004 and 2012, to identify patients 8-18 years old with chronic RHS or RHD. Patients with underlying bony abnormalities that could obscure, be confused with, or increase the risk of OCD of the elbow were excluded. Two pediatric radiologists assessed images of the elbow, grading radiocapitellar alignment as follows: normal, subluxed, dislocated, or intermittently subluxed and dislocated. Readers also reviewed images to detect capitellar OCD. The differences in the prevalence of OCD noted in elbows in each category of radiocapitellar alignment were assessed.

RESULTS

A total of 118 cases of chronic RHS, RHD, or both were detected in 100 patients. The radiocapitellar alignment of these cases was defined as follows: 53-58% were dislocated, 26-31% were subluxed, 14-15% were intermittently subluxed and dislocated, and less than 1% had normal alignment. There were 14 cases of capitellar OCD (11.9%). One elbow with OCD was categorized by both readers as dislocated, with the remaining 13 elbows (93%) deemed by the two readers to be either subluxed or intermittently subluxed and dislocated. The percentage of elbows with RHS that were found to have capitellar OCD was 32.3-33.3%, compared with 1.4-1.6% of elbows with RHD.

CONCLUSION

The prevalence of capitellar OCD is greater in elbows with RHS than in those with RHD. This finding suggests that abnormal radiocapitellar mechanics are a factor in the development of OCD. In children with RHS and new or worsening pain, capitellar OCD should be considered, and imaging strategies should be directed toward early identification of this important and treatable condition.

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.