After a discectomy or lumbar fusion, when the physiotherapist mentions the "McKenzie method" (properly called Mechanical Diagnosis and Therapy, or MDT), family members often ask: this sounds like a very professional therapy, so is it the best plan for recovery after surgery? The idea of "directional preference" is widely praised. Does that mean every patient after surgery should do a set of back-extension movements?
The core conclusion first: there is currently no direct evidence that the McKenzie method is better than other exercise after spine surgery. The evidence on rehabilitation after surgery is clear: "doing exercise is better than not doing it, but there is no ranking among which set to do". As for the directional preference that MDT stresses, its value is only inferred from research in ordinary low back pain and was not tested in patients after surgery (Oosterhuis 2014; Haddas 2025). The overall evidence analysis of core muscles and motor control after surgery is covered in detail in the main page on the evidence position of core training after spine surgery, and this page answers one specific question: does the McKenzie / MDT method hold up in the stage after spine surgery?
The state of research on the McKenzie method (MDT) after spine surgery
The most direct way to judge whether MDT has a special effect after spine surgery is to look at the research evidence for the stage after surgery. The two most representative medical reviews at present do not list McKenzie as a rehabilitation plan after surgery. The Cochrane review of rehabilitation after lumbar disc surgery covered 22 RCTs and 2,503 patients. It concluded that starting exercise at a suitable time after surgery works better than no treatment (short-term pain SMD −0.90, 95% confidence interval −1.55 to −0.24), but no particular rehabilitation model (multidisciplinary rehabilitation, behavioural graded activity, or strength / stretching training) was shown to be better than the others. The report does not mention McKenzie or directional preference at all (Oosterhuis 2014).
The latest narrative review of exercise therapy after spine surgery found the same. When researchers compared the "local" model of trunk training after surgery (specific muscle activation, similar to core stability training) with the "global" model, the pooled analysis showed no difference in effect, including after discectomy. That review does not mention the McKenzie method either (Haddas 2025). In other words, MDT is an "evidence gap" in rehabilitation after surgery. It is not that studies compared it and it lost. Medical research has simply never carried out a large direct comparison in patients after surgery.
"Not mentioned" in the literature does not mean "proven ineffective". Neither of the two large reviews lists the McKenzie method as standard practice after spine surgery, which in fact reflects the lack of research data in this area. Using MDT in patients after surgery has been shown neither to be better nor to be worse than other methods. In this situation the most practical approach is to follow the principles that do have evidence behind them, which are starting exercise at the right time, progressing step by step and making sure it is safe, and not to force the approach used for ordinary low back pain onto patients after surgery.
What the McKenzie method (MDT) is: directional preference and mechanical classification
To understand the evidence gap above, the core idea of MDT must be understood first. It is not a few fixed exercises but an assessment, classification and exercise prescription system. The therapist has the patient repeat movements in different directions to find the "directional preference", meaning a direction of repeated movement that eases the pain or draws it from the limbs towards the centre of the back, and then prescribes exercise in that direction.
The core premise here is that for MDT to be of value, the patient must actually "have a directional preference". A randomised controlled trial of 312 people with ordinary low back pain found that about 74% of subjects had a directional preference. In the group assigned to exercise in their "matched preferred direction", nobody withdrew because the condition got worse, and pain and use of painkillers fell significantly. In the two groups given exercise in the "opposite direction" and "no specific direction", about a third of people in each dropped out within two weeks (Long 2004). The study established the mechanism behind the method, but all the subjects had ordinary low back pain, and they were not patients after surgery.
Research data on MDT for ordinary low back pain
With no direct research on the period after spine surgery, looking at how well MDT works for ordinary low back pain also helps clarify its position. The medical evidence here is quite consistent: MDT does work, but it is "no better than other exercise".
- Acute low back pain vs passive treatment: pain fell by only 4.16 points and function by 5.22 points (on a 0–100 scale), statistically significant but too small to be clinically meaningful (Machado 2006)
- Acute stage vs other rehabilitation interventions: no significant difference (pain P=.11, function P=.61) (Lam 2018)
- Chronic stage vs exercise alone: a small edge (SMD −0.45); but no difference against manual therapy plus exercise (Lam 2018)
- Core stability exercise vs other exercise or manual therapy: no clinically important difference (Saragiotto 2016)
- MDT in people with a directional preference vs exercise alone: a clinically meaningful improvement in short-term pain (MD −1.53) (Hennemann 2025)
- In the same analysis vs manual therapy: the effect is usually small and not clinically meaningful; overall only low-to-moderate certainty (Hennemann 2025)
Setting the results of several studies side by side makes the picture quite clear. The advantage of MDT is both narrow and unstable. A small edge appears only when "the patient has a directional preference" and "the control group does exercise alone", and once the control group switches to manual therapy combined with exercise, the gap disappears. This is the same basic conclusion reached in the article on motor control training after surgery: "which set of exercises to pick" is not itself the deciding factor. What really decides recovery is whether the amount of exercise is enough, whether the direction of movement avoids positions that provoke pain, and whether the patient can keep going. Finding the right direction of exercise does matter, but it does not mean one particular school is better than the others.
Who directional preference exercise suits, and its limits
The one advantage of MDT that holds more promise is that it knows how to screen for and handle cases that "have a directional preference", and that beyond exercise it includes patient education and empowerment. Even so, these two features also need clear limits set objectively.
Feature 1: matching suitable exercise to patients with a directional preference
- A systematic review of managing directional preference covered 6 RCTs (5 of high quality). It found only "moderate evidence" that this approach works better than some control methods for patients with a directional preference (Surkitt 2012).
- Because the designs of the studies differed too much, the researchers could not pool the data, and the results were not consistent. In addition, the participants were people with ordinary low back pain who had a directional preference, and not patients after surgery, so the finding cannot be applied freely to everyone.
Feature 2: besides exercise, psychology and patient education
- Research has shown that MDT is linked with less fear and avoidance of activity, greater confidence in coping with pain, and less depression and psychological distress (Kuhnow 2021, covering 16 studies, 5 of them RCTs).
- The study authors also state, however, that because the methods and statistics of the studies differ widely, the findings must be read with care, and more high-quality RCTs are needed in future to confirm them. This evidence is therefore weak and can only serve as limited supporting reference.
The safety boundary: the surgical wound and internal fixation change which directions of movement are safe. All the research on directional preference is of people with ordinary low back pain (Long 2004; Surkitt 2012) and not of people who have had surgery. After spine surgery, some backward arching or forward bending movements may pull on a wound that needs protecting, or go beyond the range of movement that the internal fixation allows. The directions of exercise used for ordinary low back pain therefore must never be copied directly, and a physiotherapist must assess, according to the individual patient, which directions and ranges can be done safely.
How rehabilitation after spine surgery works in practice in Hong Kong
Applying the medical evidence above to the real setting in Hong Kong, the principles of rehabilitation are quite clear: there is no need to tie it rigidly to any one school of exercise. The key is safety first, progressing step by step, and professional supervision. After a patient goes home from a discectomy or lumbar fusion, the wound and internal fixation both limit the range of movement, and family members often do not know which directions of movement are safe. Putting the focus on "which direction can be moved safely at this stage and how much exercise to do" is far more practical than agonising over "whether to adopt the McKenzie method".
Another common situation is a patient who, after surgery, lies in bed for a long time and does not dare to move because of fear of pain and worry about loosening the screws inside (fear avoidance), which in turn slows overall recovery. On a home assessment, the physiotherapist first sets the safe range of movement according to the activity timetable the surgeon has approved and the actual state of the wound and internal fixation, and then adds progressive exercise step by step. If assessment finds the patient has a directional preference, matching the direction is certainly possible. If there is no specific preference, general progressive exercise is just as effective, and McKenzie or any single school is never used as a template to be applied rigidly. This approach matches the medical evidence, in which the key to rehabilitation after surgery is "when to start, how to progress, and having someone watch the safety", and not blindly following an exercise brand. For how to put these details into practice according to type of surgery and home setting, see the page in the same series on whether Pilates and yoga suit people after surgery, and for planning each stage of rehabilitation over time see the recovery timeline after spine surgery.
Three practical principles for choosing exercise after surgery:
- Safety first: follow the clearance timing and the wound limits—Treatment strictly follows the activity timetable approved by the surgeon and the state of the internal fixation to decide the safe direction and intensity of exercise. We do not go beyond the safe limits by blindly following the "standard movements" of a school.
- Match only if there is a preference; otherwise use progressive exercise—If the patient has a directional preference, the therapist can match exercise in that direction (Long 2004). If there is no such preference, general progressive exercise works just as well, and there is no need to force the McKenzie model.
- Value starting and keeping going more than the brand—The approach with medical evidence behind it is to start exercise early once the doctor allows, progress step by step, and have someone guide it to make sure it is safe (Oosterhuis 2014). MDT can be used as one assessment and exercise method, but it is not a must-use or better choice after surgery.
When the patient cannot tell which things are "necessary restrictions to protect the wound" and which are "safe movements that should be done more", or when, weeks after surgery, the patient still does not dare to move for fear of pain or of hurting the wound, it is time to seek a professional assessment. Nova Health's registered physiotherapists first clarify the safe limits of activity for the patient, and then, according to the type of surgery and present fitness, design a progressive exercise programme and a home training guide individually. For patients who resist activity because of fear of pain, the therapist combines rehabilitation education with gentle activity to reduce the risk of long bed rest, and does not push a single "miracle therapy". If the patient has limited mobility after surgery, a home physiotherapy assessment can also be arranged, to design suitable rehabilitation exercise directly around the real living environment.
Local resources for rehabilitation after surgery. At present the waiting time for a physiotherapy outpatient appointment in a public hospital is about 6 months to 2 years, while a private physiotherapy assessment can usually be arranged in 1 to 3 days. Patients can consider, according to their own situation, how to start rehabilitation after surgery early. In addition, the Center for Spinal Disorders under the Department of Orthopaedics and Traumatology at the University of Hong Kong (website www.ortho.hku.hk) has a multidisciplinary rehabilitation team after surgery, and the Hospital Authority extended care hospitals at Sandy Bay (including MacLehose Medical Rehabilitation Centre and Fung Yiu King Hospital) also provide multidisciplinary inpatient rehabilitation after spine surgery.