“Progressive Foot Peak Pressure Analysis after FHL Transfer for Chronic Retracted Tendo-achilles Tear” – A Pedobarographic Analysis of Normal Foot Versus Affected Foot.
ABSTRACT
Introduction
Foot pressure changes and morbidity after FHL transfer in chronic retracted TA tears have not been documented. The primary aim of our study is to analyze the peak pressure changes in various zones of the foot at each successive follow-up in the affected foot versus normal foot. The secondary aim is to determine FHL healing and Hypertrophy.
Methods
This is a prospective study of 46 patients who underwent FHL augmentation for retracted TA tears (between 2019-2022). Included TA tear >6 weeks duration and retraction >2.5cms. Excluded open TA tear,<6 weeks&retraction <2.5cms. Depending on the amount of retraction, FHL augmentation combined with TA repair/VY plasty/Turn-down-plasty. Functional outcome was analyzed with the AOFAS hallux metatarsophalangeal scale. Pedobarographic analysis was done pre-operatively at 3,6,9 months,1 year and at the final follow-up. Parameters studied-Forefoot peak pressure(FFPP), Hindfoot peak pressure(HFPP), Great toe peak pressure(GTPP), First Meta Tarso phalangeal peak pressure(MTPP), Area under the pedobarograph and Maximum pressure. At the final follow-up, MRI was done to assess FHL hypertrophy. Statistical analysis was done for these parameters using appropriate tests.
Results
Study involved 29male&17female patients, mean age-49.5 years(33-65years)&mean follow-up-26.8 months(14-38.4months). Mean AOFAS score increased from 46.04± 7.31preoperatively to 96.17± 3.22at the final follow-up(P < 0.01). There was gradual improvement noted in all Peak pressures at subsequent follow-ups, and by end of 1-year foot pressures were comparable to normal side FFPP(8.02±3.8N/cm2 to 31.35±3 N/cm2,)HFPP (36.91±5.7 N/cm2 to 25.09±3.7 N/cm2),GTPP(30.78±13.01 N/cm2 to23.17±7.5N/cm2),MTPP(5.22± 2.64 N/cm2to23.3±9.6 N/cm2). Changes in pressures were statistically significant(<0.001). 6Patients had superficial wound infections healed with antibiotics.23 patients who participated in MRI showed a mean of 27mm muscle thickness& 7.1mm tendon thickness, complete incorporation of the FHL into the calcaneum.
Conclusion
FHL transfer in Chronic Tendo-achilles tear yields good clinical outcomes and foot peak pressures and loading of the foot, though initially deranged, are restored and comparable to normal limb by the end of 1-year. GTPP and MTPP pressure attributing to loss of FHL has shown progressive improvement at the final follow-up. FHL hypertrophy provides adequate strength to repair and restore foot pressures.
Keywords: Chronic Tendo-achilles tear, FHL transfer, pedobarogram, Peak pressure, great toe, forefoot, hindfoot, TA tear
Level of evidence III: Prospective comparative study (Normal versus operated foot)
“What are the new findings?”
- Though Foot pressures are altered, peak pressures of the foot are restored and comparable to normal foot after FHL transfer for chronic retracted tendo-achilles tear.
- FHL hypertrophy is observed at the muscle and the distal tendon, thus full Tendo-achilles function is re-established.