Please cite this article in press as: Koutras G, et al. Comparison of knee flexion isokinetic deficits between seated and prone positions after ACL reconstruction with hamstrings graft: Implications for rehabilitation and return to sports decisions. J Sci Med Sport (2015), http://dx.doi.org/10.1016/j.jsams.2015.07.018 ARTICLE IN PRESS G Model JSAMS-1220; No. of Pages 4 Journal of Science and Medicine in Sport xxx (2015) xxx–xxx Contents lists available at ScienceDirect Journal of Science and Medicine in Sport journal h om epage: www.elsevier.com/locate/jsams Original research Comparison of knee flexion isokinetic deficits between seated and prone positions after ACL reconstruction with hamstrings graft: Implications for rehabilitation and return to sports decisions Georgios Koutras a , Manfred Bernard b , Ioannis P. Terzidis c , Pericles Papadopoulos d , Anastasios Georgoulis e , Evangelos Pappas e,f,∗ a Physical Therapy, Technological Education Institute of Thessaloniki, Greece b Klinik Sanssouci Potsdam—Berlin, Department of Orthopaedic Surgery, Germany c Ippokration General Hospital, Greece d Orthopaedics, General Hospital Papanikolaou, Aristotle University of Thessaloniki, Greece e Orthopaedic and Sports Medicine Center, Department of Orthopaedic Surgery, School of Medicine, University of Ioannina, Greece f Discipline of Physiotherapy, Faculty of Health Sciences, University of Sydney, Australia a r t i c l e i n f o Article history: Received 18 April 2015 Received in revised form 15 July 2015 Accepted 23 July 2015 Available online xxx Keywords: Isokinetics Graft harvesting Return to sports Strength a b s t r a c t Objectives: Hamstrings grafts are commonly used in ACL reconstruction, however, the effect of graft harvesting on knee flexion strength has not been longitudinally evaluated in functional positions. We hypothesized that greater deficits in knee flexion strength exist in the prone compared to the seated position and these deficits remain as rehabilitation progresses. Design: Case series. Methods: Forty-two consecutive patients who underwent ACL reconstruction with a hamstrings graft were followed prospectively for 9 months. Isokinetic knee flexion strength at a slow and a fast speed were collected at 3, 4, 6, and 9 months in two different positions: conventional (seated) and functional (0 ◦ of hip flexion). Results: Peak torque knee flexion deficits were higher in the prone position compared to the seated position by an average of 6.5% at 60 ◦ /s and 9.1% at 180 ◦ /s (p < 0.001). Conclusions: Measuring knee flexion strength in prone demonstrates higher deficits than in the conven- tional seated position. Most athletes would not be cleared to return to sports even at 9 months after surgery with this method. © 2015 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved. 1. Introduction Anterior cruciate ligament (ACL) tear is a common sports injury that is frequently treated surgically, particularly in the young ath- lete. The most common graft currently used for ACL reconstruction (ACLR) is the hamstrings autograft. 1 The natural history of ham- strings graft harvesting has been the topic of several investigations as there is concern about knee flexion strength deficits. It has been widely accepted that the hamstrings of most patients regenerate after harvesting for ACLR; recent research suggests that regener- ation is evident in 77% 2 to 90% of knees. 3,4 It has recently been suggested that the regenerated hamstrings tendons appear to have ∗ Corresponding author. E-mail addresses: kutrasg@otenet.gr (G. Koutras), perpap@otenet.gr (P. Papadopoulos), Evangelos.pappas@sydney.edu.au (E. Pappas). similar structure as the tendons in the non-harvested side. 2 Most studies that have investigated knee flexion strength recovery after ACLR with a hamstrings graft on isokinetic devices (typically in a seated position) found that there are no residual strength deficits 5–8 even though patients frequently describe perceived weakness. To explain this paradox, recent research has suggested that knee flex- ion strength should be measured in deep knee flexion angles where the deficits are more obvious. 4,9,10 However, in most sports that involve cutting and landing the athlete rarely needs to perform activities from deep knee flexion angles. Instead, in most situations the athlete needs to function from a position where both the knee and the hip are close to neutral position. Therefore, even when strength deficits exist in deep knee flexion angles their functional importance for most ath- letes is questionable. An alternative explanation may be that in the seated position where most studies have placed patients during isokinetic evaluations the hip is in too much flexion to replicate http://dx.doi.org/10.1016/j.jsams.2015.07.018 1440-2440/© 2015 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.