Aims. This prospective cohort study aimed to determine if the size of the tendon gap following acute tendo Achillis rupture influences the functional outcome following non-operative treatment. Patients and methods. All patients presenting with acute unilateral tendo Achillis rupture were considered for the study. Dynamic ultrasound examination was performed to confirm the diagnosis and measure the gap between ruptured tendon ends. Outcome was assessed using dynamometric testing of plantarflexion and the Achilles tendon rupture score (ATRS) six months after the completion of a rehabilitation programme. Results. 38 patients (mean age 52 years, range 29–78 years) completed the study. Patients with a gap ≥10mm with the ankle in the neutral position had significantly greater peak torque deficit than those with gaps < 10mm (mean 23.3% vs 14.3%, P=0.023). However, there was no overall correlation between gap size and torque deficit (τ=0.103), suggesting a non-linear relationship. There was also weak correlation between ATRS and peak torque deficit (τ=−0.305), with no difference in ATRS between the two groups (mean score 87.2 vs 87.4, P=0.467). Conclusion. This is the first study to identify tendon gap size as a predictor of functional outcome in acute tendo Achillis rupture, although the precise relationship between gap size and plantarflexion strength remains unclear. Large, multi-centre studies will be needed to clarify this relationship and identify population subgroups in whom deficits in peak torque are reflected in patient-reported outcome measures

A key factor delaying rehabilitation after a tendo Achillis (TA) rupture is gait abnormality. We quantified changes in planter pressures after a rupture of the TA in four groups of patients:. 15 controls subjects, mean 40 years, with no history of lower limb abnormality. 14 patients, mean 48 years, treated in a non-weight-bearing plaster cast. 12 patients, mean age 45 years, treated with immediate weight-bearing in a ‘rigid’ orthosis. 14 patients, mean age 51 years, treated with immediate weight-bearing in a ‘flexible’ orthosis. Mean and maximum peak planter pressures within the forefoot and heel were measured using in-shoe pressure pads two weeks after removal of the cast/orthosis; five gait cycles were recorded. The terminal stance and pre-swing phases were also measured as a proportion of the total stance phase of the gait cycle. One-way ANOVA was used to compare the difference in means between the groups. The normal control group had less than 2% difference between the limbs on all of the measured parameters. The patients in the plaster cast and ‘rigid’ orthotic groups had significant deficits (p = 0.04 and < 0.001 compared to control) in mean peak forefoot pressures, implying weakness in the triceps surae. However, the patients in the flexible orthosis group had only an 11% deficit (p = 0.25 compared to control). All of the patients treated for a TA rupture had increased heel pressures but only the ‘rigid’ orthotic group had cadence abnormalities (p = < 0.001). This may be the result of abnormal motor patterns secondary to mobilising in the rigid orthosis. This study highlights the gait abnormalities associated with triceps surae weakness following rupture of the TA. Accelerated rehabilitation using weight-bearing orthotics may alleviate some of these problems, but new designs for flexible orthotics may be required for maximum benefit