Dr. Sohn’s Personalized Approach
Contributing expert: Daniel G. Sohn, MD
Board-Certified Orthopaedic Surgeon
Southwest Michigan Center for Orthopaedics & Sports Medicine | St. Joseph, Michigan
Education and training: University of Chicago Pritzker School of Medicine; orthopaedic surgery residency at the University of Michigan.
Learn more about Dr. Sohn’s background and approach to care.
When knee pain starts deciding how far you can walk, whether you take the stairs, or which activities you skip, finding relief becomes personal. So does choosing a knee replacement approach.
For Dr. Daniel Sohn, an orthopaedic surgeon with Southwest Michigan Center for Orthopaedics & Sports Medicine, attention to each patient’s anatomy is central to that conversation.
“Not everybody’s anatomy’s the same,” Dr. Sohn explains. “The biomechanics are different.”
Dr. Sohn combines a Jiffy Knee surgical approach with calipered kinematic alignment, bringing together his focus on preserving soft tissues and using the patient’s original knee anatomy as the blueprint for implant placement.
Dr. Sohn’s alignment philosophy is purely kinematic: he aims to fit the replacement to the individual knee’s anatomy and balance.
Hear more on the process from Dr. Sohn in this video.
Calipered kinematic knee replacement is a technique for positioning knee replacement components to more closely reproduce a patient’s knee alignment before arthritis caused damage.
Before arthritis developed, each patient’s knee had its own natural “blueprint” – the individual alignment and relationships that guided how it moved. Dr. Daniel Sohn, MD, explains that during calipered kinematic knee replacement, he looks for and follows that original blueprint, using the patient’s anatomy to guide placement of the replacement components.
“Kinematic” refers to movement. “Calipered” describes the use of a measuring instrument to check the thickness of bone removed during surgery.
The surgeon compares those measurements with implant thickness, accounting for cartilage wear and material removed by the saw. These checks help guide implant placement. Read about the calipered technique.
It remains a form of total knee replacement. Damaged joint surfaces are replaced with artificial components; the distinguishing feature is the approach to alignment and measurement. Learn more about SWM Ortho’s knee surgery options.
How Do Jiffy Knee and Calipered Kinematic Alignment Work Together?
These terms describe different parts of the operation:
- Jiffy Knee describes the surgical approach: how he accesses the joint while working to preserve the surrounding muscles and tendons.
- Calipered kinematic alignment describes implant positioning: how surgeons like Dr. Sohn use measurements and the patient’s anatomy to guide the replacement’s alignment.
Dr. Sohn describes his approach as entering and leaving the knee while disturbing as few important structures as possible. He emphasizes avoiding cuts through the quadriceps muscle and tendon and avoiding ligament releases performed to change alignment. SWM Ortho’s joint replacement page includes information about Jiffy Knee.
Preserving these structures does not mean the operation leaves every structure inside the knee untouched. Total knee replacement still removes damaged joint surfaces, and the handling of internal ligaments depends on the implant and technique. Ask your SWM Ortho Surgeon which structures are preserved in your operation. Learn about structures involved in kinematic knee replacement.
How Does It Differ From Traditional Knee Alignment?
Mechanical alignment generally targets a neutral, straight hip-to-ankle alignment. Kinematic alignment instead aims to recreate the patient’s individual joint lines and preserve the balance of supporting ligaments, minimizing the need to release them to change their tension.
The goal is to respect the knee’s original anatomy while treating arthritic damage. The appropriate approach depends on the individual knee and the surgeon’s assessment. Learn more about these alignment principles.
Why Dr. Sohn Emphasizes Soft Tissues and Precision
In his interview, Dr. Sohn explains that his experience with partial knee replacement shaped his interest in calipered kinematic knee replacement.
“My journey through partial knee replacement is basically how I got started on calipered kinematic knee replacement,” Dr. Sohn says. “Why? Because it’s the preservation of soft tissues.”
For him, the operation involves more than choosing an implant. It requires careful attention to how that implant works with the patient’s anatomy.
“Millimeters make differences,” Dr. Sohn says.
His broader goal is to help patients move comfortably enough that their replaced joint no longer dominates their attention.
“We want you to forget you had a knee replacement,” he explains.
That describes an aspiration for recovery, rather than a result every patient can expect. Comfort, movement, and satisfaction vary.
Preserving the Knee’s Balance: A Boat-and-Ropes Analogy
Dr. Sohn compares the knee’s soft-tissue relationships to a boat secured to a dock with ropes. If the original rope lengths are preserved, the boat can return to its intended position without changing the ropes on the opposite side.
He uses that analogy to explain why he aims to preserve the knee’s existing tissue balance rather than release ligaments to achieve a standardized alignment.
He particularly emphasized the tissues along the inner, or medial, side of the kneecap. These help guide and stabilize the kneecap as the knee bends and straightens. Dr. Sohn explained that preserving those relationships allows him to avoid a lateral retinacular release – an operation that loosens tissue on the outer side of the kneecap.
This describes his surgical rationale and technique. Your SWM Ortho Surgeon can explain how kneecap tracking will be assessed in your individual knee.
When Should You Consider Knee Replacement?
An X-ray is only part of the decision. Dr. Sohn emphasizes how symptoms affect your life and whether other treatments are still helping.
“When you lose cartilage, you lose the gap between the bones,” he explains. “That doesn’t mean you need surgery. That just means that you’ve got arthritis.”
During an evaluation, you may discuss whether knee pain interrupts sleep, limits walking, or keeps you from activities you value. You will also review treatments you have tried and how well they worked.
“We always try not to choose surgery if something else works better,” Dr. Sohn says.
Depending on your condition, nonsurgical treatments may help manage symptoms. If those options no longer provide enough relief, a conversation about joint replacement can help you understand the next steps.
You Can Still Walk – and Have a Knee Problem Worth Evaluating
Dr. Sohn pointed out that walking on level ground does not tell the whole story. Some patients have significant difficulty with stairs, straightening the knee, or keeping it stable even when they can stand or walk for long periods.
Symptoms worth discussing include:
- Pain climbing or descending stairs.
- Pain or pressure while sitting with the knee bent.
- Difficulty stepping onto a single step or step stool.
- Weakness when straightening the knee.
- Buckling or giving way, especially when moving out of a straight, locked position.
These symptoms can involve the patellofemoral joint – the area where the kneecap meets the thighbone – but they do not establish a diagnosis or mean replacement is necessary. Dr. Sohn’s example also highlighted the importance of investigating other explanations for weakness, including neurological causes. An evaluation helps determine the cause and appropriate treatment.
Who May Be a Candidate?
The first question is whether you need a knee replacement. The next is which procedure and alignment approach fit your situation.
Your SWM Ortho Surgeon evaluates your symptoms, examination, imaging, overall health, and goals. Dr. Sohn also discusses factors such as diabetes control, smoking, weight, and medications that may affect healing or infection risk.
Some patients with arthritis limited to one area of the knee may be candidates for partial replacement. Others need total replacement. Calipered kinematic alignment does not make those procedures interchangeable; an individual evaluation is essential.
What Can You Expect Before Surgery and During Recovery?
Dr. Sohn describes a preparation process that includes discussing risks and benefits, completing necessary medical testing, and meeting with a nurse navigator to review the details.
He notes that many of his joint replacement procedures are performed on an outpatient basis. Whether you go home the same day depends on your health, surgical plan, and readiness for discharge.
Dr. Sohn connects his tissue-preserving approach with the potential for easier early recovery: avoiding muscle and tendon cuts is intended to maintain the structures that help straighten the knee and guide the kneecap. Recovery still varies, and this explanation does not establish a faster recovery time for every patient.
Rehabilitation remains an important part of knee replacement recovery. Dr. Sohn explains that knee replacement physical therapy may continue for a month or two, depending on the patient. Completing formal therapy does not necessarily mean recovery is finished.
SWM Ortho’s physical therapy services support rehabilitation close to the physician office. Dr. Sohn values that proximity because it helps the care team communicate and respond when a patient needs additional attention.
Your team will provide instructions for activity, exercises, swelling management, and incision care. Contact the practice promptly with concerns rather than waiting for a scheduled visit.
What Are the Risks and Limitations?
Calipered kinematic knee replacement carries the risks of total knee replacement, including infection, blood clots, stiffness, persistent pain, nerve or blood vessel injury, and implant problems that may require another operation. AAOS explains knee replacement risks and expectations.
Personalized alignment also does not guarantee faster recovery, comfortable kneeling, or a knee that feels exactly like your original joint. The most useful discussion is how the proposed approach fits your knee, your health, and your expectations.
Frequently Asked Questions
1. Is “caliper knee surgery” the same as calipered kinematic knee replacement?
People may use “caliper knee surgery” as shorthand. The more specific term is calipered kinematic knee replacement, describing the measurement method and alignment approach used during replacement surgery.
2. Is Jiffy Knee the same thing as calipered kinematic alignment?
They describe different aspects of surgery. Jiffy Knee concerns surgical access and tissue preservation; calipered kinematic alignment concerns positioning the replacement. Dr. Sohn combines them in his approach. The caliper itself is a measuring instrument, not an implant left inside your knee.
3. Is this a partial or total knee replacement?
This article describes a technique for total knee replacement. Partial replacement treats a more limited area of the knee and has different candidacy requirements.
4. Does this technique require a robot?
No. Calipered kinematic alignment can be performed with manual surgical instruments. Ask your SWM Ortho surgeon which tools and checks will be used in your operation. See the surgical technique overview.
5. Will my knee feel completely natural afterward?
That is a goal, not a promise. Dr. Sohn describes wanting patients to forget they have a replaced joint, but some people continue to notice stiffness, discomfort, or differences in sensation.
6. Will I still need physical therapy?
Yes, you should expect a rehabilitation plan after knee replacement. The exercises, frequency of visits, and duration depend on your needs and progress. Learn about physical therapy at SWM Ortho.
7. Will I be able to kneel after surgery?
Kneeling can remain uncomfortable after knee replacement. Discuss this goal before surgery and ask your care team when and how to try it safely. Calipered alignment does not guarantee comfortable kneeling. Read AAOS guidance on recovery expectations.
8. How long will the replacement last?
Dr. Sohn notes that knee replacements can last 20 to 25 years, but individual implant life varies. No alignment technique can guarantee a particular lifespan. Your surgeon can discuss wear, activity, and other factors relevant to you.
9. How do I find out whether this approach is right for me?
Schedule an evaluation with one of our Orthopaedic Surgeons. Bring questions about your symptoms, previous treatments, daily limitations, and recovery goals. Together, you can discuss whether surgery is appropriate and which approach fits your needs.
Explore Your Knee Treatment Options in Southwest Michigan
You do not have to decide on surgery before seeking answers. A consultation can help you understand what is causing your pain and what options are available.
To discuss knee care with Dr. Daniel Sohn, or any of our other Orthopaedic Surgeons, at Southwest Michigan Center for Orthopaedics & Sports Medicine, call (269) 428-3500 or submit an appointment request.
Move Better. Live Stronger.
This article provides general education and does not replace an individual medical evaluation.