Psychological and Knee Function Measures at 1 Month Predict High Kinesiophobia at 6 Months After Anterior Cruciate Ligament Reconstruction: Development and Internal Validation of a Prognostic Model
This study developed and internally validated a prognostic model showing that psychological and knee-function measures, particularly the TSK-17 score, taken one month after ACL reconstruction can predict high kinesiophobia at six months, though the current sample size limits the precision of individual risk estimates and necessitates external validation.
Original paper licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). This is an AI-generated explanation of the paper below. It is not written or endorsed by the authors. For technical accuracy, refer to the original paper. Read full disclaimer
When a person suffers a torn knee ligament, the physical repair is only half the battle. Surgeons can stitch the tissue back together, and physical therapists can guide the muscles to regain strength, but the body's ability to move freely often depends on the mind. Many patients develop a deep-seated fear of moving their knee again, worrying that any step or turn will cause a new injury. This hesitation, known as kinesiophobia, can keep people from returning to sports or even daily activities, even when their knee is physically healed. Doctors have long suspected that the way a patient feels about their recovery in the weeks immediately following surgery might predict whether this fear will stick around for months. The question is whether a simple check-up one month after the operation can reveal who is likely to struggle with this fear six months later, and if adding more details about their mood and confidence improves the prediction.
Researchers at Sichuan Provincial Orthopedics Hospital set out to build a tool to answer this question. They followed a group of adults who had undergone surgery to reconstruct a torn anterior cruciate ligament. The team decided to use the one-month mark after surgery as a specific checkpoint. By this time, patients have experienced the operation and the initial phase of rehabilitation, so their answers to questions about their knee and their feelings reflect a real, lived experience rather than just a pre-surgery worry. The researchers wanted to see if they could look at a patient's status at that one-month point and accurately forecast whether they would still be suffering from high levels of fear of movement six months after the surgery.
To do this, the team gathered data from 177 patients who completed all the necessary surveys. At the one-month mark, they measured several things: the patient's age and sex, their current level of fear regarding movement, their confidence in returning to sports, their belief in their ability to perform knee tasks, their anxiety levels, and their subjective feeling of how well their knee was working. They then waited until the six-month mark to see who still had high fear. The researchers defined high fear as a specific score on a standard questionnaire designed to measure movement anxiety. They found that nearly half of the patients in their group, 84 out of 177, still had high levels of this fear at six months.
The study tested three different ways of making a prediction. The first method used only basic information like age and sex. This approach was not very good at guessing who would have high fear later. The second method added the patient's fear score from the one-month visit. This single addition made the prediction much stronger, correctly identifying most of the patients who would struggle later. The third method was the most complex, adding all the other measurements—confidence, anxiety, and knee function—to the mix. While this full model performed slightly better on paper than the second method, the improvement was so small that the researchers could not be certain it was real. The data suggested that the extra details did not add enough new information to make the prediction significantly more accurate than simply knowing how afraid the patient was at the one-month mark.
The researchers also checked how reliable their model was by running thousands of simulated tests on their own data to see if the results were just a lucky fluke. Even after these rigorous checks, the model showed a slight tendency to be too optimistic about its own accuracy, a common issue when the number of patients is not large enough. The study concluded that while the one-month fear score is the most powerful clue for predicting future fear, the current group of patients was too small to create a perfect tool for judging individual risk. The model is best viewed as a promising starting point for future research rather than a finished medical rule. It suggests that if a patient is still very afraid of moving their knee one month after surgery, they are likely to remain that way six months later, but doctors cannot yet rely on a complex formula of many different factors to change that outcome with certainty.
The findings highlight a critical window for intervention. Because the fear measured at one month is such a strong predictor, this early stage of recovery offers a clear opportunity for medical teams to step in. If a patient shows high fear at this point, they might benefit from extra support, such as psychological counseling or a tailored rehabilitation plan that gradually exposes them to movement in a safe way. However, the researchers are careful to state that this tool is not yet ready for use in every clinic. It needs to be tested on a much larger group of people from different hospitals to confirm that it works reliably for everyone. Until then, the most valuable lesson is that the mind and the knee are deeply connected, and addressing the fear of movement early in the recovery process may be just as important as fixing the ligament itself.
Drowning in papers in your field?
Get daily digests of the most novel papers matching your research keywords — with technical summaries, in your language.