Cory Calendine, M.D.

06/13/2026

Sleep is one of the hardest parts of recovering from a knee replacement, and one of the least talked about. In the first weeks after surgery, many of my patients cannot get comfortable, wake repeatedly, and start to worry that something went wrong. It almost never has.

Here is what I want patients to know. Disrupted sleep early on is normal and expected. It comes from several things stacked together: surgical pain that is worst at night, your body's stress response, the effects of anesthesia on your sleep cycles, and simply not being able to get into your usual position. The pattern is also predictable. Sleep disturbance tends to peak around six weeks, then steadily improves.

Why it matters: sleep and pain run in both directions, so protecting your rest is part of recovery, not a luxury. The strongest, safest tools are behavioral, and I share them all here, along with honest cautions on sleep aids and CBD and when to call your surgeon.
Read the full guide:

Why is sleep so hard after knee replacement, and how long does it last? An orthopaedic surgeon shares what actually helps you rest and recover.

06/11/2026

What’s Inside a Knee Replacement?
Ever wonder what’s actually inside a new knee? A total isn’t one part — it’s a precision system of up to (4) components, each engineered for a specific job. Here’s the build, piece by piece.
- Femoral component: caps the end of the thighbone; typically cobalt-chromium — scratch-resistant, highly polished, and durable — curved to recreate the natural shape of the femur with a central groove that lets the kneecap track smoothly as you bend and straighten.
- Tibial component: baseplate of the whole construct; titanium or cobalt-chromium, this tray anchors into the top of the shinbone, often with a stem for stability, and holds the next piece in place.
- Spacer, or polyethylene insert: sits between the two metal parts; medical-grade, highly cross-linked plastic is your new cartilage — the low-friction cushion that lets the joint glide. Components are designed so metal always articulates against plastic, which means smoother motion and less wear over time. This bearing surface is the part most likely to wear, and it’s where decades of material science have made the biggest difference.
- Patella button: optional 4th piece — a small polyethylene dome that resurfaces the back of the kneecap. Not every knee needs it; that’s a surgeon’s call based on your anatomy.
With more than 150 implant designs available, the right combination comes down to your bone quality, activity level, and goals. No single brand is proven superior — what matters is matching the construct to the patient. Modern total remains one of the most successful procedures in orthopedics, restoring mobility and quality of life for millions.
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06/10/2026

The Figure-4 Hip Test: How Surgeons Find the Source of Groin Pain
When a patient comes in with groin, hip, or buttock pain, the FABER is a common test, also called Patrick’s test. The name is an acronym for the movement sequence: Flexion, ABduction, and External Rotation of the hip.
The setup is simple. With the patient lying on their back, we bring your leg into a figure-four position, resting the ankle of the tested leg just above the opposite knee. We stabilize the pelvis at the anterior superior iliac spine, then apply gentle downward pressure on the bent knee. The goal is to load the hip joint + sacroiliac joint and see whether familiar symptoms appear. Pain felt in the front of the hip or deep in the groin points more toward intra-articular hip pathology (femoroacetabular impingement, labral tear, osteoarthritis). Pain felt in the back of the pelvis near the sacroiliac joint suggests that joint may be the pain generator instead. Limited motion without much pain can reflect tightness in muscles like the iliopsoas. A positive test simply means symptoms or restricted motion were reproduced. A negative test means they were not. It is important to understand the limits here. The FABER test indicates something is irritated, not exactly which tissue is involved. The evidence shows it is sensitive but not highly specific, so we can’t rely on it alone.
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06/10/2026

If you smoke and have a hip or knee replacement coming up, quitting may be the most powerful step you can take to protect your new joint, and the timing matters more than most people realize.

Smoking narrows your blood vessels and lowers the oxygen your body needs to heal. That's why smokers face higher rates of deep infection, slower bone and wound healing, and a greater chance of early implant problems. Research shows smoking can raise the risk of a deep joint infection by about 2.16 times.

Here's the encouraging part: quitting just 4 to 6 weeks before surgery can cut your complication risk significantly, and the benefit keeps growing the longer you stay smoke-free. Even one or two smoke-free weeks lowers your risk.

In this surgeon's guide, Dr. Cory Calendine walks through the real numbers, a simple quit timeline, how va**ng and ni****ne products fit in, and where to find support to quit for good.
Read the full guide here:
https://corycalendinemd.com/blog/quit-smoking-before-joint-replacement-surgery/

06/09/2026

From a Glass Shard to a 65-Year Hip Implant
When performing a through the anterior approach, we’re using a road map drawn by a Norwegian immigrant who arrived in Wisconsin at 16, barely speaking English. Dr. Marius Nygaard Smith-Petersen (1886–1953) became, in the words of Dr. William Harris, “the most innovative orthopedic surgeon of the Western Hemisphere.” In 1916, as a young assistant, he watched a hip exposed the old way — the patient surviving “by a very narrow margin.” Trained under the great neurosurgeon Harvey Cushing to respect tissue planes, he was convinced there had to be a better way. A senior colleague’s challenge was simple: “Why don’t you figure one out?” The next day he took a cadaver and did. The Smith-Petersen anterior approach is still used in operating rooms worldwide.
That was only the beginning. After noticing how the body had wrapped a glass shard in a smooth, glistening membrane, he wondered: what if you placed a smooth surface inside an arthritic hip and let the body heal around it? That question launched the mold arthroplasty (1923) — and a relentless materials search through glass, Pyrex, and Bakelite before a dentist’s suggestion led him to a cobalt-chrome alloy that finally worked. One of those cups functioned in a patient for 65 years. His 3-flanged nail turned a into a faster recovery, saving untold thousands. And in 1936 he described femoral neck impingement that the field wouldn’t “rediscover” for 60 yrs. He wasn’t chasing fame. He was chasing a better answer - a standard every surgeon should hold.
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