Scientists have discovered that being able to maintain a comfortable walking pace is a key factor in determining someone’s surgical outcome and recovery.

A new study out of Kyushu University in Japan tested patients' walking speed before hip replacement surgery by having them walk about 52 feet. It found that those who could walk at a moderate pace of one meter per second, 2.2 miles per hour, or faster,  were significantly more likely to report positive results and a smoother recovery.

Researchers specifically studied patients with osteoarthritis, a condition affecting 32 million Americans that involves the breakdown and eventual loss of joint cartilage, and who needed total hip arthroplasty, where surgeons replace the damaged hip joint with an artificial one.

Among factors that influenced patient outcomes, such as age and pain level, walking speed was the only significant predictor of excellent surgical outcomes. 

Patients who could keep up with the pace were also less likely to think about or notice their new hip in the years following their surgery.

Walking speed is a composite vital sign of a patient's overall health, with the healthy average being about 1.3 meters per second (3 mph). How fast a person can walk tests leg strength, stability and coordination when walking, pain level when moving and cardiovascular fitness.

The results show that a walking speed test performed before moving the patient to the operating table is the most useful single predictor of pain and function a full year after a hip replacement.

Dr Yuki Nakao, an orthopedic surgeon and lead author of the study, said in a statement: ‘Its simplicity also makes it a practical measure that clinicians can easily incorporate into their routine preoperative assessment.’

Researchers tracked 483 osteoarthritis patients. Before their surgeries, physical therapists ‘routinely’ measured pain, hip range of motion, lower-limb strength and 10-meter self-selected gait speed under standardized conditions.

The authors of the study did not specify the frequency of the 'routine' measurements.  

The surgeries took place sometime between 2012 and 2018. In August 2023, the researchers mailed questionnaires to all 483 patients, and 274 patients responded.

These questionnaires included the Oxford Hip Score to assess hip pain and function and the Forgotten Joint Score-12, which measures patients' awareness of their hip joint and level of discomfort.

Researchers used a statistical model to determine which of the roughly 15 factors they measured, such as age, BMI, pain intensity, hip range of motion, limb strength and walking speed, actually predicted how happy patients were years later.

Researchers used a machine-learning algorithm to impartially sort patients into groups based on their long-term recovery scores. This identified a distinct ‘excellent outcome’ group made up of patients who achieved top marks for low pain, high function and barely thinking about their new hip in daily life.

When they analyzed pre-surgery data to identify predictors of membership in the excellent outcome group, walking speed was the only significant factor.

Patients who walked faster than one meter per second before surgery were nearly six times more likely to end up in the excellent outcome group. 

Further analysis provided a practical context for this speed benchmark. A walking speed of 0.7 meters per second was associated with achieving an acceptable level of pain relief and function.

The more ambitious one meter per second, however, was the threshold linked to patients largely forgetting about their artificial joint, the hallmark of the best possible outcome.

Finally, the study identified the physical traits that enable faster pre-op speed, finding that better hip flexibility, stronger hip muscles and lower pain levels were each independently associated with a quicker gait, revealing modifiable factors that contribute to meeting the key recovery target.

Nakao said: ‘We hope that bringing this knowledge into clinical practice will support better recovery and ultimately improve outcomes for patients undergoing hip replacement surgery.’

The latest research was published in the Journal of Bone & Joint Surgery.

Doctors often recommend an exercise regimen to patients expecting to go under the knife for a hip replacement. 

In 2020, Italian researchers asked whether a brisk walk of just about 32 feet the day of surgery helped speed up recovery.

Patients were assessed on their Functional Independence Measure (FIM), a score of their ability to perform basic daily activities like self-care and walking before surgery and at three and seven days after.

They found that people who walked the morning of their surgery achieved a crucial level of functional independence, measured by their ability to perform basic daily tasks, a full four days earlier than those who began walking the day after surgery.

By the third day post-op, the early-walkers had reached a level of independence that the non-walking group did not achieve until a week after their operation.

The pre-op walking advantage was most pronounced when it came to performing self-care tasks, such as feeding, grooming and getting dressed. The early-walking group had a one-week lead over the non-walking group in this area.

The researchers also found no downsides to walking before surgery. The early walkers did not experience any added hip pain, hindered hip function or reduced quality of life.