The decision to proceed to ACL surgery is reached after a careful history, examination and interpretation of the MRI investigations and a discussion with the patient. High level athletes and elite sportspeople require surgery to get back to playing sport at their previous pre-injury level. Non-elite athletes and normal people who have sustained an ACL injury should consider whether they would like to undergo surgery to restore stability to their knee but not everyone requires an ACL reconstruction to have stability. A small proportion of patients can regain knee stability with physiotherapy alone. This depends on a number of factors and these are best discussed with your consultant knee surgeon.
In some individuals, despite physiotherapy, the knee carries on giving way even when walking and therefore surgery becomes essential. In other patients walking and running in a straight line is okay but any twisting or turning results in the giving way of the knee and if the patient requires this level of function, then an ACL reconstruction is recommended. Some individuals have manual jobs which are very strenuous and require complete knee stability and therefore for these individuals an ACL reconstruction is also recommended.
For individuals with high levels of function and demands from their knee (professional sports people and high functioning non-professionals), an ACL reconstruction is usually required to regain knee stability.