Weakness in end-range plantar flexion after Achilles tendon repair.
BACKGROUND
Separation of tendon ends after Achilles tendon repair may affect the tendon repair process and lead to postoperative end-range plantarflexion weakness.


OBJECTIVE
Patients will have disproportionate end-range plantarflexion weakness after Achilles tendon repair.


METHODS
Descriptive laboratory study.


METHODS
Four-strand core suture repairs of Achilles tendon were performed on 1 female and 19 male patients. Postoperatively, patients were nonweightbearing with the ankle immobilized for 4 weeks. Plantarflexion torque, dorsiflexion range of motion, passive joint stiffness, toe walking, and standing single-legged heel rise (on an incline, decline, and level surface) were assessed after surgery (mean, 1.8 years postoperative; range, 6 months-9 years). Maximum isometric plantarflexion torque was measured at 20 degrees and 10 degrees of dorsiflexion, neutral, and 10 degrees and 20 degrees of plantar flexion. Percentage strength deficit (relative to noninvolved leg) was computed at each angle. Passive dorsiflexion range of motion was measured goniometrically. Passive joint stiffness was computed from increase in passive torque between 10 degrees and 20 degrees of dorsiflexion, before isometric contractions.


RESULTS
Significant plantarflexion weakness was evident on the involved side at 20 degrees and 10 degrees of plantar flexion (34% and 20% deficits, respectively; P <.001), with no torque deficits evident at other angles (6% at neutral, 3% at 10 degrees of dorsiflexion, 0% at 20 degrees of dorsiflexion). Dorsiflexion range of motion was not different between involved and noninvolved sides (P = .7). Passive joint stiffness was 34% lower on the involved side (P <.01). All patients could perform an incline heel rise; 14 patients could not perform a decline heel rise (P <.01).


CONCLUSIONS
Disproportionate weakness in end-range plantar flexion, decreased passive stiffness in dorsiflexion, and inability to perform a decline heel rise are evident after Achilles tendon repair. Possible causes include anatomical lengthening, increased tendon compliance, and insufficient rehabilitation after Achilles tendon repair.


CONCLUSIONS
Impairments will have functional implications for activities (eg, descending stairs and landing from a jump). Weakness in end-range plantar flexion may be an unrecognized problem after Achilles tendon repair.
Mullaney
Michael J
MJ
Nicholas Institute of Sports Medicine & Athletic Trauma, Lenox Hill Hospital, New York, NY 10021, USA. mike@nismat.org
McHugh
Malachy P
MP
Tyler
Timothy F
TF
Nicholas
Stephen J
SJ
Lee
Steven J
SJ
D000125:Achilles Tendon / Q000293:injuries* / Q000502:physiology / Q000601:surgery; D000328:Adult; D016512:Ankle Injuries / Q000503:physiopathology*; D000843:Ankle Joint / Q000503:physiopathology*; D005260:Female; D006365:Heel / Q000502:physiology; D006801:Humans; D007866:Leg / Q000502:physiology; D008297:Male; D008875:Middle Aged; D018908:Muscle Weakness / Q000503:physiopathology; D018482:Muscle, Skeletal / Q000503:physiopathology; D016059:Range of Motion, Articular; D020127:Recovery of Function / Q000502:physiology; D012421:Rupture / Q000503:physiopathology / Q000601:surgery; D019415:Torque