Superior Transposition of Horizontal Rectus Muscles Corrected Hypotropia in Two Traumatic Third Nerve Palsy Cases

Two surgical case reports published in BMC Ophthalmology describe how an unusual tendon-transfer technique helped reduce severe downward deviation of the eye in patients with chronic traumatic third nerve palsy. The report, authored by Mazen Abdullah Alqahtani and Fawzia Alhaimi and published on 29 October 2026, details individualized combined procedures, each built around a Knapp-type superior transposition of the horizontal rectus muscles.

Severe traumatic third nerve palsy can produce a disabling combination of problems: the eye drifts outward (exotropia), downward (hypotropia), the lid droops, and ocular motility becomes markedly limited.

The first patient was a 27-year-old man with a chronic traumatic left third nerve palsy who retained some residual adduction. Preoperative synoptophore assessment measured an exotropia of 40 prism diopters and a hypotropia of 30 prism diopters. He underwent an augmented Knapp-type procedure, in which the full tendons of both horizontal rectus muscles were transposed superiorly with posterior augmentation sutures, combined with a 6-millimeter recession of the lateral rectus and a 6-millimeter resection of the medial rectus.

Nine months after surgery, his residual exotropia and hypotropia each measured 6 prism diopters, and he reported no diplopia. That represents a substantial reduction from the preoperative deviations, though not a complete normalization of alignment.

The second patient, a 27-year-old woman with a chronic traumatic right third nerve palsy, presented with a larger exotropia of 55 prism diopters, a hypotropia of 25 prism diopters, and an eye held in a depressed position. Forced-duction testing revealed mild restriction to passive elevation, suggesting some mechanical component in addition to the palsy itself.

Her treatment was staged. She first underwent a 6-millimeter inferior rectus recession together with an augmented full-tendon superior transposition of the lateral rectus alone, a single-muscle variant of the Knapp-type procedure. Persistent exotropia was then addressed with horizontal rectus surgery on the fellow eye. At five months after the second operation, her visual acuity was 20/20 in both eyes, the exotropia measured 25 prism diopters, and the vertical deviation was 0 prism diopters. The operated eye reached the primary position, but active elevation was not restored, graded as elevation minus 4.

Diplopia outcomes differed between the two patients. The first man denied double vision after surgery. The second woman continued to experience horizontal diplopia, although she had no vertical or torsional diplopia. Double Maddox rod testing showed no subjective torsion, and fundus photography showed no objective torsion, indicating the procedure did not induce rotational misalignment of the eye.

The authors are explicit about the limits of what these cases demonstrate. Both operations combined several procedures at once, so the contribution of the transposition cannot be separated from that of the concurrent recessions, resections, or fellow-eye surgery. Active elevation was not restored in either patient, and the second patient’s residual horizontal deviation and diplopia persisted.

The report is framed as hypothesis-generating rather than practice-changing. With only two patients, no control group, and individualized operative plans, the observations do not establish a treatment algorithm, a deviation threshold for selecting the technique, or superiority over other surgical approaches for traumatic third nerve palsy. They do, however, document that in carefully selected chronic cases, superior transposition of the horizontal rectus muscles, whether as a two-muscle augmented procedure or a single-muscle variant, was followed by correction or meaningful reduction of primary-position hypotropia.

Subject of Research: Surgical management of hypotropia in severe traumatic third nerve palsy using superior transposition of the horizontal rectus muscles

Article Title: Management of hypotropia in severe traumatic third nerve palsy using superior transposition of the horizontal rectus muscles

Article References: Alqahtani, M. A., & Alhaimi, F. (2026). Management of hypotropia in severe traumatic third nerve palsy using superior transposition of the horizontal rectus muscles. BMC Ophthalmology. https://doi.org/10.1186/s12886-026-05484-3

Image Credits: AI Generated

DOI: 10.1186/s12886-026-05484-3

Keywords: third nerve palsy, hypotropia, strabismus surgery, superior transposition, horizontal rectus muscles, Knapp procedure, case report, ocular motility, diplopia, BMC Ophthalmology, Management, severe