Unfortunately, injuries to the anterior cruciate ligament (ACL) are relatively common in sports that involve turning, twisting, and/or landing after a jump, such as football, basketball, and handball. This injury is sometimes referred to as ‘a heart attack for the knee’. Treatment often involves a reconstruction of the ACL in order to improve the stability and function of the knee joint. The vast majority of sportspeople expect to make a full recovery and return to their sport with no restrictions afterwards. However, it would appear that only 65% of patients resume sport at the same level as before the ACL reconstruction. In addition, every fifth amateur sportsperson injures their ACLagain. This may be connected with the timing of their return to sport, one of the most difficult decisions that a physiotherapist has to make. In many cases, the decision about when to resume a sport is based on the rehabilitation period, without any prior objective measurements. Human movement scientist Wouter Welling tried to identify factors that would provide objective support when making this decision.
Battery of tests
For his research, Welling developed a battery of tests, which included specific tests for measuring important aspects such as muscle strength, stability, and quality of movement. As this is not only a physical, but also a mental challenge, they also included questionnaires asking about whether the sportspeople felt mentally prepared to return to sport. The tests were done at the end of the rehabilitation period. It appears that the sportspeople who scored better in the tests had a better chance of returning to their pre-operative level of sport.
Reduced quality of movement
The uninjured leg is often used as a reference for analysing the leg that has suffered an injury. Welling’s research shows that it is not always a reliable point of reference, because the injury, operation, and subsequent period of inactivity also affect the uninjured leg. The study also revealed a difference in the quality of movement between the injured and the uninjured leg; the injured leg showed reduced quality of movement. This might account for the heightened risk of re-injuring the anterior cruciate ligament.
More intensive training during rehabilitation
Welling shows that only a small proportion of the sportspeople satisfy the criteria for a full and safe return to sport. Just 50% of them meet the criteria for muscle strength. For that reason, Welling enhanced the quality of the rehabilitation programme by introducing more progressive strength training, after which a lot more sportspeople met the criteria for muscle strength. The quality of the rehabilitation would therefore appear to be a decisive factor. These results show that sportspeople can satisfy the criteria if they train long and hard enough during the rehabilitation period. Alongside rehabilitation exercises in the gym, Welling would like to see sport-specific field training for all sportsmen and women who want to return to their sport. This sport-specific field training serves as the bridge between rehabilitation and the actual return to sport. Many sportspeople considered this to be a positive part of their rehabilitation.
Risk of repeat injury
In his research, Welling also tried to identify the sportspeople who had a heightened risk of injuring their ACL again. He compared the test results of the sportspeople who incurred a second ACL injury with the results of those who did not. Welling found no difference between the test results for these two groups. To his mind, this means that the current criteria cannot be used to identify which sportspeople are at greater risk of a repeat injury.
Wouter Welling (1989, Harfsen) studied human movement science in Groningen. He conducted his research in the SHARE research institute of the UMCG. His thesis is entitled: ‘Return to sport after an anterior cruciate ligament reconstruction. Are we there yet?’ Since his PhD research, he has been working as an embedded sport scientist at Pro-F.