Schneeberger and colleagues measured how much the radial head and coronoid resist posterolateral rotatory displacement of the elbow, and whether radial head replacement and coronoid reconstruction restore it.
Sequential‑sectioning study of 7 cadaver elbows from donors with a mean age of 82, ligaments intact or reattached, under combined valgus and supination torque.
Key Findings
With collateral ligaments intact, radial head excision raised posterolateral rotatory laxity to 18.6°, from 9.0° in the testing model. Adding a 30% coronoid resection dislocated every elbow.
A rigid metal radial head restored near‑normal stability (11.4° vs 9.0°, p = 0.18). A bipolar floating head left 16.9° of laxity (p < 0.0001), though no elbow dislocated.
With 50% of the coronoid gone, neither implant alone fully stabilized the elbow (16° rigid, 20.1° floating). With 70% gone, laxity of 22° and 26° persisted.
Coronoid reconstruction plus radial head replacement restored stability. With an olecranon‑tip graft, laxity exceeded the testing model by only 1.1° (rigid) and 4.3° (floating), neither significant.
Detaching the lateral ulnar collateral ligament alone produced 32.7° of laxity, with dislocation in 4 of 7 elbows.
Limits: 7 specimens, no soft‑tissue healing in vitro and one rigid implant design. The authors could not set the coronoid defect size that requires reconstruction.
Authors' conclusion
The results of this study suggest that the coronoid and the radial head contribute significantly to posterolateral rotatory stability.
Schneeberger and colleagues measured how much the radial head and coronoid resist posterolateral rotatory displacement of the elbow, and whether radial head replacement and coronoid reconstruction restore it.
Sequential‑sectioning study of 7 cadaver elbows from donors with a mean age of 82, ligaments intact or reattached, under combined valgus and supination torque.
Key Findings
With collateral ligaments intact, radial head excision raised posterolateral rotatory laxity to 18.6°, from 9.0° in the testing model. Adding a 30% coronoid resection dislocated every elbow.
A rigid metal radial head restored near‑normal stability (11.4° vs 9.0°, p = 0.18). A bipolar floating head left 16.9° of laxity (p < 0.0001), though no elbow dislocated.
With 50% of the coronoid gone, neither implant alone fully stabilized the elbow (16° rigid, 20.1° floating). With 70% gone, laxity of 22° and 26° persisted.
Coronoid reconstruction plus radial head replacement restored stability. With an olecranon‑tip graft, laxity exceeded the testing model by only 1.1° (rigid) and 4.3° (floating), neither significant.
Detaching the lateral ulnar collateral ligament alone produced 32.7° of laxity, with dislocation in 4 of 7 elbows.
Limits: 7 specimens, no soft‑tissue healing in vitro and one rigid implant design. The authors could not set the coronoid defect size that requires reconstruction.
Authors' conclusion
The results of this study suggest that the coronoid and the radial head contribute significantly to posterolateral rotatory stability.