Special Situations: Overweight

July 1, 2025

Special Situations: Overweight

Anterior Cruciate Ligament (ACL) injuries are already complex to manage. When a patient is overweight or obese, additional challenges arise both for recovery and for long-term joint health. Body weight also impacts ACL injury patterns, surgical outcomes, rehabilitation progress, and future risk of re-injury or joint degeneration. It’s important to also note that overweight does not necessarily mean inactive, and yet some of the special issues may still apply.

Note that there is a concept called Health at Every Size. Part of the idea is to point out that there’s nothing that makes people automatically healthy just because they’re at a certain size. That being said, there are some realities of potential risk – or at least believed to be – for being overweight. This document is meant to present some of those potential issues with regard to ACL injury issues. You and your care team will have to determine if or when such concerns apply to you and your situation.

Anecdotally, there are stories of some doctors who don’t mention weight issues at all, whereas there are others who might recommend against surgery based on weight factors. Everyone of course has the right to proper care. And it’s also important that anyone be fully informed for any issues they may be facing. In other words, overweight patients should be properly informed and prepared regarding any issues weight may play in their care decisions, in a factual and helpful way.

The Mechanics: Why Weight Matters

The ACL stabilizes the knee by resisting forward motion and rotation of the tibia (shinbone) relative to the femur (thighbone). When excess body weight is involved, it increases the force placed on the knee joint, especially during walking, stair climbing, squatting, or pivoting. This elevated stress can increase chances of overweight individuals having ACL tears, particularly during low-impact events that would not typically cause injury in someone of average weight.

Diagnosis and Pre-Surgical Considerations

For overweight individuals, diagnostic imaging such as MRI is just as effective, but physical exams may be harder to interpret due to excess soft tissue. If surgery is recommended, special attention must be given to anesthetic risks, positioning during surgery, and choice of graft (autograft vs. allograft), as healing capacity and mechanical load tolerance may differ.

Decision making may be different for bariatric patients as well. For any patient, part of the calculation as to whether or not surgery is a good option includes intent for future activity. As an easy example, a college sports start with a clear ACL tear and meniscus damage is highly likely to opt for surgery. For someone past middle age who is mostly sedentary, they might opt out of surgery. At the same time, that very same person might also want to consider that for those overweight, their knees are already potentially more at risk due to extra weight, and therefore that might tilt back towards wanting surgery. Or there’s an intent to become more active. The point is there may be a lot of factors going into a choice for how to manage an injury and recovery.

Surgical Challenges in Overweight Patients

Increased body mass index (BMI) may impact:

Surgical visualization and access: Extra tissue can make arthroscopic procedures technically more difficult.
Higher infection rates: Obesity is associated with greater risk of post-operative infection.
Delayed wound healing: Circulation and inflammatory responses can be altered in obesity, leading to slower recovery.
Increased risk of graft failure: More mechanical load across the new ligament may strain its healing capacity.

That said, ACL reconstruction can still be highly successful for patients with higher BMIs, especially when paired with thoughtful prehab and rehab planning.

Rehabilitation Adjustments

Physical therapy remains essential. However, modifications may be needed:

Low-impact cardio: Ellipticals, recumbent bikes, and aquatic therapy are preferred over treadmills or step-ups in early stages.
Emphasis on quadriceps activation: Overweight individuals often struggle with quad inhibition post-surgery, which impairs gait and joint control.
Longer progression timelines: Healing and strength building can take more time due to greater joint loads and possible pre-existing mobility deficits. However, note that it’s also possible that some particular exercises may be easier for some. For example, someone overweight may have fairly strong legs and be able to progress faster for some exercises.
Rehabilitation Protocols: A great deal of ACL type injuries are due to some form of athletics. Concomitantly, rehab protocols are often designed for highly active individuals. It’s likely such protocols should be adjusted for those who may have weight issues.
Mobility Concerns: Among those who are overweight there are many cohorts, just as with any group. Some folks may be very active and strong and just happen to be carrying a few extra pounds. Others may be more sedentary. This may present very different mobility issues. The ability to use crutches an other mobility selections may have to be taken into account. As well, other medical devices and rehab equipment may need to be considered in terms of it’s size and strength.
Weight during Recovery: Some people may lose weight during recovery if they don’t eat much in the early weeks due to pain or discomfort. However, it’s as or more likely that being much less active puts everyone at more risk of weight gain. Post op nutrition is important, however it’s also likely a good idea to pay attention to possible weight gain during a period of decreased activity, and safely adjust where possible.

Custom bracing or supportive taping may help provide confidence during early movement retraining.

Weight Loss as Treatment

Weight management should not be viewed as cosmetic. It’s medically significant for joint longevity. Losing just 10% of body weight can reduce knee joint load by hundreds of pounds per day. Incorporating nutritional guidance, behavioral support, and physician-monitored plans into ACL rehab often improves outcomes.

Weight loss during recovery can:

Reduce re-injury risk
Improve gait mechanics
Lower the chance of post-traumatic osteoarthritis

It might be sensible to coordinate with bariatric specialists if more aggressive intervention is warranted.

Mental and Emotional Support

Overweight patients sometimes experience shame or discouragement during the recovery process, especially if progress is slower than expected. It’s possible other patients may progress faster through physical therapy and this may be challenging to see. It’s important to understand that everyone’s recovery journey will vary greatly, regardless of weight. People will often look to others to try to determine some baselines for their own efforts. For those who are overweight or obese, it’s possibly looking towards those who are more physically fit might create negative feelings. On the other hard, it’s also possible for someone technically overweight to be heavily active and involved in sports, even more so than those to whom they may be comparing themselves. The bottom line is that consideration of mental state is important, whatever it may be, because it’s critical that anyone in recovery maintain their momentum back to the best level of healthfulness they desire.

Summary

ACL injury recovery in overweight individuals demands a more individualized, multidisciplinary approach. With surgical expertise, thoughtful rehabilitation, and holistic health planning, including weight management, patients can still achieve excellent outcomes. In any case, it’s important to treat such issues as just another data point. Anyone struggling with such an injury is going to need help. And there’s a variety of special cases that may require particular kinds of assistance. Being overweight or obese is just something to take into consideration when making choices.

Updated Web References

Obesity and Orthopedic Surgery Outcomes

Weight Loss and Joint Health

Weight Loss Benefits for Arthritis – Arthritis Foundation

Research and Clinical Studies

Editor