Category:Ankle; Hindfoot; Midfoot/Forefoot; OtherIntroduction/Purpose:Increasing evidence has shown that gastrocnemius tightness is related to various types of foot and ankle pathology. The recession and lengthening of the gastrocnemius has become an important ancillary procedure in many reconstructive operations, such as hallux valgus, pes plano-valgus and total ankle arthroplasty surgery. Additionally, isolated Gastrocnemius Recession is also performed alone to treat plantarfasciitis, achillestendinosis, metatarsalgia and diabetic forefoot ulceration. The reports about the clinical results are encouraging, but evident data about the resulting strength of the treated muscle is lacking.Methods:This study was designed to measure calf-strength of every patient before and after Gastrocnemius Tenotomy, Gastrocnemius Recession, Achillestendon lengthening. The data was taken before surgery and one year post-op. A Leonardo Mechanograph GRFP was used to measure calf-strength with bended and extended knee on both sites. 85 patients were measured before surgery. 58 of these patients underwent a intervention on the sural complex. The interventions included Gastrocnemius Tenotomy, Gastrocnemius Recession, Achillestendon lengthening combined with different types of foot and ankle reconstruction.Results:The results show that the calf strength decreased overall significantly. The force on the operated site decreases significantly with bended and extended knee. However, contralatrel forces diminish in the same dimension. The decrease in force was mainly related to the force during knee extension. There was no significant force difference postoperatively between ipsi- and contralateral.Conclusion:Apparently, a surgical intervention on the foot seems to cause a weakening of the flexor muscles on both lower legs. Not surprisingly, the greater reduction in strength is during knee extension. Apparently, however, the loss of strength on the operated foot is compensated, so that ultimately there is the same strength on both side.