2017 ISAKOS Biennial Congress ePoster #1040


Why Do Some Patients Miss Out on Returning to Normal Function After Primary Anterior Cruciate Ligament Reconstruction?

Bertrand Semay, MRes, Chatswood, NSW AUSTRALIA
Vincent V. G. An, MD, BSc, Newtown, NSW AUSTRALIA
Corey Scholes, PhD, Crows Nest, NSW AUSTRALIA
David A. Parker, MBBS, BMedSc, FRACS, Sydney, NSW AUSTRALIA

Sydney Orthopaedic Research Institute, Chatswood, NSW, AUSTRALIA

FDA Status Cleared


Some patients do not appear to return to normal function after ACLR, and may be identified pre-operatively by particular patient and injury characteristics.



Arthroscopic reconstruction is the clinical standard for the treatment of ACL rupture. The primary goal of surgery is to restore normal knee function, and eliminate symptoms of pain and instability during daily life and sports activities. Procedure failure is often defined in terms of graft failure; however this tends to ignore a potential sub-group of patients who do not return to normal function with an intact graft. Currently, surgeons lack guidance to counsel patients regarding return to function, despite the volume of research on the topic, even if this is critical to the patient’s surgical expectations. The purpose of this study was to assess return to normal in primary ACLR at a minimum of 12month follow-up and identify patient and injury characteristics associated with below-normal function post-operatively.


Patient-reported outcomes (IKDC) data from a cohort of primary ACLR in a clinical research registry, aged 18 years or more at surgery was extracted for analysis. Patient demographics and anthropometry, as well as injury and surgical details were collated. IKDC subjective scores were collected pre-operatively and at a minimum follow-up 1 year. Each patient’s score was normalized to age and gender matched population data (z-score), with those 1 or more standard deviations below the population mean considered below-normal. Binary logistic regression tested for significant predictors of post-operative group membership (below vs normal functioning).


A cohort of 289 primary ACLR patients (201 males; 30.3+9.7yrs; 78.8+15.8kg, 174.1+9.4cm; 1.4+0.8yrs of follow-up) was included for analysis. The median IKDC z-score improved from 2.1 (IQR 1.4 – 2.8) standard deviations below normal preoperatively, to equivalent to normative data postoperatively (z-score =< 0.1, IQR -0.5 – 0.4). Postoperatively, a proportion of patients (12%) met the criterion for below-normal function. Below-normal functioning patients were differentiated from the remainder of the cohort by significantly lower pre-operative z-scores (P<0.01), increased injury to surgery delay (P<0.01), and the presence of lateral femoral condyle cartilage injury (P = 0.04) and medial meniscal injury (P = 0.04).


This is the first study to quantify the proportion of patients (88%) that return to normal function at a minimum of 12month follow-up after ACL reconstruction, with the majority indistinguishable from normal ranges. The factors identified here may help the surgeon in counselling certain patients with respect to surgical expectations and could contribute to patient selection and treatment planning. Further work is required to examine the predictive ability of a broader set of patient, injury and surgical factors on patient reported outcome measures.