Other knee pain after knee replacement can appear when the leg that did not have surgery begins doing more than usual. It may help you stand, climb stairs, get into the car, and steady yourself while your surgical leg rebuilds strength and control.
This does not automatically mean your other knee has been damaged or that another knee replacement is inevitable. It does mean that both legs deserve attention during rehabilitation.
Why your other knee may become more noticeable
After a unilateral knee replacement, people commonly place more weight through the leg that did not have surgery. That leg may handle a larger share of standing, sitting, stepping, and balance tasks, especially during the early weeks.
Existing arthritis can also contribute. A 2024 study followed people with osteoarthritis in both knees after unilateral knee replacement. Pain in the opposite knee increased in 14.6% of participants at one month, 24.1% at three months, and 27.6% at six months. Lower quadriceps strength and more advanced arthritis in the opposite knee were among the identified risk factors.1
Your surgical leg and your other leg work as a team. Supporting both legs can make everyday movement more manageable.
Not every ache has the same explanation. Symptoms may reflect additional activity, existing arthritis, muscle fatigue, a change in walking pattern, or another condition. New pain should not automatically be labeled as compensation without considering the full picture.
Other knee pain after knee replacement can affect function
The condition of your other knee can influence walking, balance, stairs, and other daily activities. Research has associated greater opposite-knee pain with lower functional activity after knee replacement.1 Other studies have found that symptoms in the opposite knee can influence how people judge their overall surgical results.2
Walking patterns also play a role. People may continue placing less weight through their surgical leg during standing and squatting tasks, even after formal rehabilitation has begun.3 This can leave the other leg responsible for more of the work.
The goal is not to force equal weight through both legs before your surgical leg is ready. A physical therapist can assess your strength, balance, pain, and movement pattern and decide when more symmetrical movement is appropriate.
If walking still feels cautious or uneven, Walking Like Yourself Again After Knee Replacement provides a concise framework for understanding the elements that contribute to a more natural walking pattern.
Build strength on both sides
Strengthening after knee replacement should not focus exclusively on your surgical leg. Your quadriceps, hamstrings, hips, and calf muscles on both sides contribute to standing, walking, stair use, and balance.
The specific exercises and resistance should be selected for your current abilities. More resistance is not automatically better. An exercise that is appropriate for one person may be poorly timed for another person with greater pain, swelling, balance limitations, or additional medical concerns.
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Resistance bands provide several resistance levels in a small, portable format. They can be useful when a physical therapist has selected band exercises for your hips or legs and shown you how to perform them correctly.
A ProBody Pilates large Swiss ball offers another option for supported exercises selected by your therapist. Its larger surface can be useful for certain seated, positioning, balance, or supported strengthening activities. Because a large ball can move unexpectedly, it should only be used in an environment and manner that fit your balance ability.
The kisnbld 9-inch mini Pilates ball is compact, inexpensive, and easy to store. It can work well as a positioning aid, a tactile cue, or light resistance during exercises prescribed by a physical therapist. Its small size makes it a practical option when you do not want bulky exercise equipment in your home.
These tools create options, but none is required for everyone. The useful tool is the one that supports an appropriate exercise and is simple enough for you to use consistently.
Use pacing before fatigue changes your movement
Your other knee may become more uncomfortable when standing and walking tasks accumulate throughout the day. Instead of completing every errand or household task in one stretch, consider dividing physically demanding activities into smaller blocks.
For example, grocery shopping and laundry do not have to occur back to back. Alternating a standing task with a seated task may reduce fatigue in both legs. Shorter walks performed more consistently may also be easier to manage than one exhausting walk.
Watch for patterns across several days. Notice whether symptoms increase after stairs, prolonged standing, longer walks, or repeated sit-to-stand movements. That information can help you describe what is happening when you speak with your physical therapist or surgeon.
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When your other knee deserves an evaluation
A mild increase in awareness or soreness after a more active day may settle when activity is adjusted. Persistent or escalating symptoms deserve closer attention.
Contact an appropriate healthcare professional if your other knee develops substantial swelling, redness, warmth, repeated giving way, locking, a sudden inability to bear weight, or pain following a fall or injury. Calf swelling, chest pain, or shortness of breath requires prompt medical attention.
Research has found that some people eventually undergo knee replacement on the opposite side, particularly when advanced arthritis was already present.4,5 That possibility does not mean every new symptom predicts another surgery. Your examination, symptoms, function, imaging, preferences, and response to nonsurgical care all contribute to that decision.
Support both legs as one system
Your other knee has an important job after knee replacement, but it should not be expected to carry every demanding task indefinitely. Strengthening both legs, pacing activity, and improving weight distribution as your surgical leg becomes more capable may help reduce unnecessary strain.
If symptoms are interfering with walking or daily activities, an individualized assessment can identify whether strength, mobility, balance, arthritis, or another factor needs attention.
Episode 27 continues the series with a pre-surgery confidence checklist covering practical preparation for your body and home.
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This article provides general educational information and does not diagnose the cause of pain, replace an examination, or establish a physical therapist-patient relationship. Follow the instructions provided by your surgeon, physical therapist, and healthcare team.
References
- Kamitani T, Wada O, Mizuno K, Kurita N. Contralateral knee pain exacerbation after total knee arthroplasty and its impact on functional activity. Arch Orthop Trauma Surg. 2024;144(4):1713-1720. doi:10.1007/s00402-023-05163-8
- Clement ND, Bardgett M, Weir D, Holland J, Gerrand C, Deehan DJ. Contralateral knee pain reduces the rate of patient satisfaction but does not clinically impair the change in WOMAC score after total knee arthroplasty. Knee. 2020;27(1):167-172.
- Rossi MD, Eberle T, Roche M, et al. Use of a squatting movement as a clinical marker of function after total knee arthroplasty. Am J Phys Med Rehabil. 2013;92(1):53-60. doi:10.1097/PHM.0b013e3182643a66
- McMahon M, Block JA. The risk of contralateral total knee arthroplasty after knee replacement for osteoarthritis. J Rheumatol. 2003;30(8):1822-1824.
- Aljehani MS, Christensen JC, Snyder-Mackler L, Crenshaw JR. Knee biomechanics and contralateral knee osteoarthritis progression after total knee arthroplasty: a systematic review. Gait Posture. 2022;91:123-134. doi:10.1016/j.gaitpost.2021.10.015