PARTIAL KNEE REPLACEMENT · UNICOMPARTMENTAL · FRANKLIN, TN
Partial Knee Replacement Surgery
in Franklin, TN
When only part of your knee is worn — replacing only that part is often the better answer.
OF KNEE REPLACEMENT PATIENTS ARE EXCELLENT PARTIAL KNEE CANDIDATES
CONVERSION RISK OVER 10 YEARS — PRIMARY TRADE-OFF TO UNDERSTAND
FASTER OVERALL RECOVERY COMPARED TO TOTAL KNEE REPLACEMENT
UNDERSTANDING YOUR KNEE
Think of Your Knee as Three Rooms
The knee is not one joint — it is three distinct compartments, each doing its own job. Understanding this is the starting point for understanding why partial knee replacement exists and when it is the right choice.
The medial compartment sits on the inner side of the knee, between the femur and tibia. The lateral compartment mirrors it on the outer side. The patellofemoral compartment sits at the front of the knee, where the kneecap meets the thigh bone.
Together these three compartments make up the functional knee joint. Osteoarthritis does not always affect all three compartments equally. In many patients — particularly earlier in the disease process — the cartilage loss and bone damage are confined to one compartment while the others remain largely intact and healthy.
If you have ever described your knee pain as focal — a specific spot on the inner or outer side of the knee, or under the kneecap — rather than pain throughout the entire joint, that pattern may reflect single-compartment disease.
When arthritis is isolated in one room, total knee replacement replaces all three — including the two that are working fine. Partial knee replacement addresses only the damaged compartment, leaving the healthy surfaces of your knee exactly as they are. Medial compartment knee replacement accounts for roughly 80 percent of Dr. Calendine’s partial knee cases — consistent with where knee arthritis most commonly begins. Lateral unicompartmental and patellofemoral replacement are performed less frequently but are offered when the anatomy and disease pattern support them.
| Medial Compartment | Location / Description | Typical Treatment |
|---|---|---|
| Inner Knee Compartment | Outer Side of Knee | Front of Knee |
| ~80% of Partial Replacement | Less Common Procedure | Kneecap + Thigh Bone |
WHAT THE RESEARCH SHOWS
Less Surgery, Faster Recovery, a More Natural-Feeling Knee
When only the damaged compartment is replaced, the surgery is fundamentally less disruptive than a total knee replacement. The healthy bone, cartilage, and ligaments in the other two compartments remain untouched. The incision is smaller. The reconstruction is more limited. And because more of your native knee is preserved, many patients describe the result as feeling more like their own joint.
The Forgotten Joint Score — A Validated Measure of Natural Knee Feel
That last point is supported by published research. The Forgotten Joint Score — a validated outcome measure that asks how often patients are aware of their artificial joint during daily activities — consistently shows higher scores for partial knee replacement than for total knee replacement.
In plain terms: patients who have had a partial knee replacement are more likely to go about their daily life without thinking about their knee at all. One study reported mean Forgotten Joint Scores of 65.4 for unicompartmental replacement compared to 50.2 for total knee replacement — a statistically significant difference. Other studies show higher scores in both groups, but the pattern holds: partial knee replacement consistently outperforms total knee replacement on this measure when the right patient receives the right procedure.
The goal of partial knee replacement is not just less pain — it is a knee that feels and moves more like the one you were born with.
Recovery — Specific Milestones
Recovery is meaningfully faster across the board. Weight-bearing begins immediately after surgery. Most patients use a walker for a matter of days — primarily for balance — before transitioning to a cane. Physical therapy typically runs about four weeks, compared to six weeks for total knee replacement. Across nearly every recovery milestone, partial knee replacement runs approximately 30 to 40 percent ahead of total knee replacement. Virtually all partial knee replacement patients go home the same day as surgery.
SIDE-BY-SIDE COMPARISON
Partial Knee vs. Total Knee Replacement — At a Glance
| Factor | Partial Knee Replacement | Total Knee Replacement |
|---|---|---|
| Incision size | Healthy compartments left completely intact | All three compartments resurfaced |
| Joint preserved | Smaller: less tissue disruption | Standard: full joint access required |
| Incision size | Limited to affected compartment only | All three compartment surfaces prepared |
| Bone removal | Mako Partial Knee components, designed for Mako precision placement | Full knee implant system |
| Implant | Always: Mako precision critical for matching native anatomy | Always: Mako for precision alignment |
| Robotic guidance | Immediate | Immediate |
| Weight-bearing | Days, if at all | Days to ~2 weeks typically |
| Walker use | ~4 weeks typical | ~6 weeks typical |
| Overall recovery pace | ~30 to 40% faster across milestones | Standard total knee timeline |
| Conversion risk | ~10% over 10 years if arthritis progresses to other compartments | None: all surfaces resurfaced |
| "Forgotten joint" scores | Consistently higher: patients more likely to forget they have an implant | Strong long-term outcomes; scores generally lower than partial |
WHAT HAPPENS DURING PARTIAL KNEE REPLACEMENT SURGERY
The Partial Knee Replacement Procedure — Step by Step
Anesthesia and Surgical Access
Partial knee replacement is technically more demanding than total knee replacement. This is not a paradox — it is a direct consequence of what makes the procedure valuable. In a total knee replacement, all three compartment surfaces are resurfaced. The mechanical environment is rebuilt comprehensively. In a partial knee replacement, the implant must integrate seamlessly with two intact, healthy compartments that have their own native geometry, cartilage thickness, and alignment.
If the partial implant is placed even slightly off — in size, position, or orientation — the result is a mismatch between the artificial compartment and the natural ones. That mismatch creates uneven loading, accelerated wear, and a knee that does not feel right. Matching a partial implant precisely to your native anatomy is a problem that demands precision guidance technology.
This is why Dr. Calendine uses the Stryker Mako® Partial Knee system for every partial knee replacement he performs — medial unicompartmental, lateral unicompartmental, and patellofemoral replacement alike.
How Mako® Partial Knee Works
The workflow begins before surgery. A CT scan of your knee generates a precise three-dimensional digital model of your specific anatomy. Dr. Calendine uses that model to plan implant size, position, and orientation in advance. In the operating room, the Mako system tracks the position of your knee in real time and provides continuous guidance so that the implant is placed exactly where the pre-operative plan specifies.
What changes for partial knee is the precision standard. Because the implant components are designed specifically for Mako® placement and for integration with an otherwise intact joint, the system’s real-time three-dimensional data is not just helpful — it is the mechanism by which accurate, anatomy-matched placement is achieved. The Mako Partial Knee components are purpose-built for this application.
Every partial knee replacement Dr. Calendine performs uses the Mako system. There is no circumstance in which he would perform a partial knee replacement without it.
Dr. Calendine's Depth of Experience with the Mako® Platform
Dr. Calendine serves as a consultant to Stryker® and has trained peers nationally and internationally on robotic joint replacement. The precision standards that matter most in unicompartmental replacement — tibial slope, component sizing, rotational alignment, and integration with native anatomy — are the ones he has spent years refining. This depth of experience with the platform directly informs how he uses the system for partial knee cases.
That same experience shapes how he prepares patients before surgery. Each partial knee candidate is evaluated to confirm that a single compartment is the true source of pain, because a partial replacement only succeeds when the rest of the joint remains healthy. Dr. Calendine reviews imaging, alignment, and ligament stability with every patient so the surgical plan fits their individual anatomy. When a knee is well suited to the partial approach, that careful planning is what lets him preserve healthy bone, protect the surrounding ligaments, and restore movement that feels natural to the patient.
CANDIDACY FOR PARTIAL KNEE REPLACEMENT
Am I a Candidate for Partial Knee Replacement?
Partial knee replacement is genuinely the better operation for the patients who qualify for it. The question is whether your
knee — your specific anatomy, your arthritis pattern, your symptoms — fits the criteria that make it work.
The Anatomy Has to Be Right
The most important factor is single-compartment disease. If your arthritis is confined to one area of the knee — typically the medial compartment, but sometimes lateral or patellofemoral — and the other compartments are intact, partial knee replacement is a legitimate option. If the arthritis has affected multiple compartments, total knee replacement is the more appropriate procedure.
Other anatomic requirements include intact ligaments (the MCL, LCL, and PCL must all be functional), adequate range of motion (a flexion contracture of less than 10 degrees and the ability to bend the knee to at least 90 to 100 degrees), and a deformity that is correctable or largely correctable. For most partial knee designs — including the fixed-bearing implant Dr. Calendine uses — an intact ACL is not required. This is a meaningful distinction from certain other implant designs that do require it.
The Symptoms Have to Match
The right candidate describes focal pain — pain in a specific part of the knee, not the whole joint. Pain that worsens with activity and improves with rest is the classic presentation. Patients with significant pain at rest or with a pattern suggesting inflammatory arthropathy — which affects the joint environment globally — are typically better served by total knee replacement.
Conservative Treatment Should Come First
Partial knee replacement is still a significant surgery. Patients who have not yet tried physical therapy, anti-inflammatory medications, activity modification, or injections should exhaust those options before pursuing surgery. Dr. Calendine will review your treatment history at your consultation and support continued non-surgical management when it is
providing meaningful relief.
Younger and More Active Patients
Younger, more active patients are disproportionately represented among partial knee replacement candidates. The appeal is real: less surgery, faster recovery, and a more natural-feeling knee are goals that align closely with an active lifestyle. Partial knee replacement can be an excellent choice for younger patients — and it is also an appropriate option at any age when the anatomy and symptoms support it.
The honest trade-off to understand is that arthritis can develop in the compartments that were not treated. If that happens — and in roughly 10 percent of patients it does over 10 years — a second surgery to convert the partial replacement to a total knee replacement may be needed. That conversion is typically similar in scope to a primary total knee replacement, though the prior implant and any associated bone changes are addressed as part of the procedure. It is another surgery, and it should be weighed honestly against the meaningful benefits the partial replacement provides in the years before that conversion would ever be needed — if it is needed at all.
Approximately 10 to 15 percent of knee replacement patients are excellent candidates for partial knee replacement. Another 20 to 30 percent may warrant evaluation. The consultation is the only reliable way to determine where you fall.
WHAT RECOVERY LOOKS LIKE AFTER PARTIAL KNEE REPLACEMENT
What to Expect — Surgery and Recovery
The Day of Surgery
Partial knee replacement is performed at the Bone and Joint Institute of Tennessee Surgery Center or at Williamson Medical Center, both in Franklin,
Tennessee. Virtually all patients go home the same day as surgery. The procedure is performed under spinal anesthesia, typically takes less time
than total knee replacement, and patients are walking before they leave.
Early Recovery — First Two Weeks
Weight-bearing begins immediately. Most patients use a walker for a few days at most — for balance and confidence, not because the leg cannot support weight. The transition to a cane follows quickly, and many patients are walking without any assistive device within one to two weeks. Return to driving typically occurs when you are walking steadily with a cane and off narcotic pain medication, which for many partial knee patients happens faster than after total knee replacement.
Physical Therapy and Milestones
Physical therapy following partial knee replacement typically runs about four to six weeks, compared to six to eight weeks for total knee replacement patients — a reflection of how much less tissue disruption occurs. The exercises are similar in type but progression tends to move faster. Dr. Calendine's expectation is that patients reach most recovery milestones approximately 30 to 40 percent ahead of the total knee timeline, though individual recovery always varies and that variation is normal.
Activity | Long-Term Expectations
The preserved native compartments of the knee contribute to a more natural range of motion and movement pattern in many patients. Higher-impact activities and return to an active lifestyle are goals Dr. Calendine takes seriously in partial knee candidates. Long-term outcomes data for well-selected partial knee patients is strong, and satisfaction rates in appropriately chosen candidates are consistently high. The 10 percent conversion risk over 10 years is real and worth understanding before surgery.
Same-day discharge. Walking before leaving the facility. Spinal anesthesia – this limits feeling groggy.
Walking immediately with a walker. Managing stairs. Returning to basic home activities. A waterproof bandage (with all the
stitches under the skin) allows you to shower right away.
Wean off the cane. Bend and walk. You can drive when you are walking steady and off all narcotics.
Physical therapy typically complete (~4 weeks vs. ~6 weeks for TKR). PT optimizing motion and strength now. Most milestones 30–40% ahead of TKR timeline. Must manage swelling.
Full recovery for most patients. No restrictions. Ready for anything.
IN HIS OWN WORDS
Dr. Calendine on Partial vs. Total Knee Replacement
Two Surgical Facilities in Franklin, Tennessee
Dr. Calendine performs partial knee replacement at two facilities in Franklin, Tennessee — both located at or affiliated with the Bone and Joint Institute of
Tennessee, 3000 Edward Curd Lane in Franklin, Tennessee.
| Bone and Joint Institute of Tennessee Surgery Center | Williamson Health |
|---|---|
| Franklin, TN: Outpatient ambulatory surgery center. Virtually all partial knee replacement patients go home the same day. | Franklin, TN: Full-service hospital for patients who prefer or benefit from overnight observation. |
| https://bjitsurgerycenter.com/ | https://williamsonhealth.org |
FREQUENTLY ASKED QUESTIONS
Frequently Asked Questions — Partial Knee Replacement
What is partial knee replacement and how is it different from total knee replacement?
The knee has three compartments — the medial (inner), lateral (outer), and patellofemoral (between the kneecap and the thigh bone). In total knee replacement, all three compartment surfaces are resurfaced with metal and plastic components. In partial knee replacement, only the compartment affected by arthritis is replaced. The healthy cartilage, bone, and ligaments in the other compartments are left completely intact.
The practical consequence is a procedure that involves less bone removal, a smaller incision, and less overall disruption to the knee. Patients who have had a partial knee replacement often describe the result as feeling more natural than a total knee replacement — more like the knee they were born with, because more of their original anatomy was preserved.
Partial knee replacement is also called unicompartmental knee replacement, or simply a uni. The terms are interchangeable. The specific variant — medial, lateral, or patellofemoral — refers to which of the three compartments was treated.
What are the different types of partial knee replacement — medial, lateral, and patellofemoral?
Each type of partial or unicompartmental knee replacement addresses a specific compartment of the knee joint.
Medial unicompartmental knee replacement addresses the inner side of the knee — the most common location for knee arthritis and the most frequently performed partial knee replacement. The vast majority of Dr. Calendine’s partial knee cases are medial.
Lateral unicompartmental knee replacement addresses the outer side of the knee. Arthritis isolated to the lateral compartment is less common, and the surgical technique is more demanding due to differences in lateral knee anatomy.
Patellofemoral knee replacement addresses the compartment between the kneecap and the thigh bone — the front of the knee. Patients with patellofemoral arthritis often describe pain going up and down stairs or with prolonged sitting. When the arthritis is isolated to this compartment, patellofemoral replacement can be a highly effective option.
Dr. Calendine performs all three types using the Mako Partial Knee system, with implant selection tailored to which compartment requires treatment.
How does the Mako® Partial Knee system work — and why is it important for partial knee replacement?
The Mako Partial Knee system is a robotic-arm assisted surgical platform designed specifically for unicompartmental knee replacement. Dr. Calendine uses it for every partial knee replacement he performs.
The process begins before surgery. A CT scan of your knee generates a precise three-dimensional digital model of your specific anatomy. Dr. Calendine uses that model to plan implant size, position, and orientation in advance. In the operating room, the Mako system tracks your knee in real time and provides continuous guidance so that the implant is placed exactly where the pre-operative plan specifies.
Precision matters more in partial knee replacement than in total knee replacement because the implant must integrate seamlessly with the intact compartments of your native knee. Even a small placement error creates a mismatch that affects how the knee loads, moves, and feels. The Mako system — paired with implant components purpose-built for this application — is how that precision standard is reliably met.
Who is a good candidate for partial knee replacement?
The ideal candidate for partial knee replacement has arthritis that is isolated to one compartment of the knee, with the other compartments remaining healthy. In practical terms, this often means a patient who describes pain in a specific location — the inner or outer side of the knee, or under the kneecap — rather than diffuse pain throughout the entire joint. Pain that increases with activity and improves with rest is the classic pattern.
Additional requirements include intact knee ligaments, a functional range of motion (able to bend the knee at least 90 to 100 degrees, with minimal or no contracture when the knee is straightened), and a deformity that is largely correctable. Patients should also have tried non-surgical treatments — physical therapy, anti-inflammatory medication, or injections — before pursuing surgery.
Approximately 10 to 15 percent of knee replacement patients are excellent candidates. Another 20 to 30 percent may warrant evaluation. The consultation — including a review of your X-rays and a thorough examination — is the only reliable way to determine whether you qualify.
Is partial knee replacement a good option for younger or more active patients?
Younger, active patients are well represented among partial knee replacement candidates, and for good reason. Less bone is removed. The healthy portions of the joint are preserved. Recovery is faster — roughly 30 to 40 percent ahead of total knee replacement across most milestones. And the long-term data on Forgotten Joint Scores — a measure of how naturally patients move through daily life without awareness of their implant — consistently favors partial over total knee replacement in well-selected patients.
Partial knee replacement is also appropriate for older patients when the anatomy and symptoms support it. The procedure is not defined by age — it is defined by the pattern of disease in the knee.
The honest consideration for any patient is the conversion risk: roughly 10 percent of partial knee replacement patients require conversion to a total knee replacement over 10 years if arthritis develops in the other compartments. For a younger patient, understanding that this may be one step in a longer journey — rather than a permanent final solution — is part of the informed decision. The years of better function, faster recovery, and more natural knee feel that a well-performed partial knee replacement provides are real and meaningful even if conversion is eventually required.
What is the risk that a partial knee replacement will need to be converted to a total knee replacement?
The primary long-term risk of partial knee replacement is the development of arthritis in the compartments that were not treated. Because partial knee replacement leaves the other two compartments intact, those surfaces remain susceptible to the same degenerative process that affected the first compartment. If that progression occurs, conversion to total knee replacement may be needed.
The risk of requiring conversion is approximately 10 percent over 10 years. The large majority of partial knee replacement patients — about 90 percent — do not require conversion within that timeframe.
If conversion does become necessary, it is typically similar in scope to a primary total knee replacement. The prior partial implant is removed, any associated bone changes are addressed, and a total knee replacement is completed. The overall postoperative course is generally comparable to a first-time total knee replacement. It is a second surgery, and that is a real consideration — but it does not represent a failed outcome. It reflects the natural progression of arthritis in a knee that has already benefited from years of improved function following the partial replacement.
Surgery & Recovery
What does recovery from partial knee replacement look like — how is it different from total knee replacement?
Recovery from partial knee replacement follows the same general path as total knee replacement, but runs meaningfully faster at nearly every milestone. Weight-bearing is immediate. Most patients use a walker for a matter of days — for balance rather than necessity — before transitioning to a cane. Return to driving typically occurs once you are walking steadily without narcotic pain medication.
Physical therapy typically runs about four weeks for partial knee replacement, compared to six weeks for total knee replacement. The exercises are similar in type; the pace of progression is faster because the knee has experienced less overall disruption. Dr. Calendine’s expectation is that patients reach most recovery milestones approximately 30 to 40 percent ahead of a standard total knee timeline. Individual recovery varies, and that variation is normal — but the general pattern is consistent.
The most common patient observation is that the knee feels responsive earlier. Because more of the native joint is intact, early range of motion and confidence in the leg tend to return sooner.
Does Dr. Calendine perform partial knee replacement for patients from outside of Franklin?
Yes. Dr. Calendine performs partial knee replacement for patients from throughout Middle Tennessee and beyond. His office and surgical facilities are located in Franklin at the Bone and Joint Institute of Tennessee — accessible from Nashville, Brentwood, Murfreesboro, Spring Hill, Nolensville, Smyrna, Hendersonville, Mt. Juliet, Columbia, Antioch, Thompson’s Station, Gallatin, Belle Meade, Fairview, La Vergne, Arrington, College Grove, Leipers Fork, and communities across the region. Out-of-state patients are also welcome.
For patients traveling for surgery, Dr. Calendine’s team works to structure your consultation and surgical scheduling to minimize the number of trips required before your surgery date. Many partial knee replacement patients find the same-day discharge and faster recovery makes the logistics of traveling for surgery more manageable than they expected.