Imageless vs. CT-Scan Based Robotic Knee Surgery: Why VELYS Is Changing Orthopedics in Ahmedabad
Written by Dr. Hardik M Shah, MBBS (Gold Medal), MS Orthopedic, FRCS (Germany) | Reviewed by Dr. Swagat M Shah, MS Ortho, DNB Ortho | DHS Multispecialty Hospital, Ahmedabad
DHS Hospital — Orthopedic Technology Series
Two robotic systems walk into an OR. One brings a pre-planned CT map from yesterday. One maps your anatomy in real-time. Here's why your soft tissues care — and why the difference matters more than any brochure tells you.
Robotic knee replacement surgery has moved from novelty to mainstream in India — but not all robots work the same way. When families in Ahmedabad research their options, they often see brand names like Mako, ROSA, and VELYS listed side by side, as if they are interchangeable. They are not.
The single most important technical distinction between these systems is whether they require a CT scan before surgery — or whether they map your actual anatomy during the procedure. That difference has real consequences for your radiation exposure, your wallet, your surgical timeline, and how well your implant fits your knee on the day you actually go under anaesthesia.
At DHS Multispecialty Hospital, Gurukul, Ahmedabad, lead orthopaedic surgeon Dr. Hardik M. Shah chose the VELYS Robotic-Assisted Solution by Johnson & Johnson DePuy Synthes specifically because it is imageless. This post explains exactly what that means, why it matters, and how it compares to every alternative available in Gujarat today.
What Does "Imageless" Actually Mean?
In everyday language, "imageless" simply means the robot does not rely on pre-taken images — specifically a CT scan — to plan or guide your surgery. To a family who has never seen a surgical robot, that might sound like cutting corners. It is precisely the opposite.
Traditional CT-based robotic systems like Mako (Stryker), ROSA (Zimmer Biomet), and Cuvis require the patient to undergo a full CT scan weeks before the operation. That scan is fed into the robot's planning software, which generates a virtual model of your bone anatomy. The surgeon studies this model, plans bone cuts digitally, and on surgery day, the robot executes those pre-planned cuts.
VELYS does something fundamentally different. Instead of working from a scan taken days ago, it registers your actual bone anatomy inside the operating theatre, in real time, using specialised tracking probes and an infrared optical navigation system. It builds a live 3D model of your specific knee the moment surgery begins — no scan, no radiation, no pre-planning window.
Why Real-Time Registration Matters More Than Pre-Planned
- Your body is not the same from one day to the next. Swelling, fluid, and soft tissue tension in the knee can shift between your CT scan date and your surgery date.
- A pre-planned model is a snapshot of your knee from the past. VELYS works with your knee as it exists right now, under anaesthesia, with actual soft tissue tension in the room.
- Real-time registration allows the surgical team to detect and respond to intraoperative surprises — bone quality variations, cartilage loss patterns — that no pre-operative scan could fully predict.
- The surgeon can update the plan mid-procedure. A robot locked into a CT-based blueprint cannot course-correct without significant workflow interruption.
Imageless does not mean less information. It means more current, more relevant information, gathered at the exact moment decisions are made.
The CT-Scan Burden: What Older Robots Ask of You
Before a patient can have surgery with a Mako, ROSA, or Cuvis robot, they must complete a mandatory pre-operative CT scan. This step is not optional — it is built into the clinical workflow of these systems. For patients in Ahmedabad who are already managing pain, limited mobility, and the logistical demands of surgical preparation, this adds a significant burden.
What CT-Based Robotic Surgery Requires Before You Enter the OR
- Separate CT scan appointment: You must travel to a radiology centre — adding an additional trip and wait time, inconvenient especially for elderly patients with limited mobility.
- Radiation exposure: A musculoskeletal CT scan of the knee and lower limb carries an effective dose of approximately 0.3–1.0 mSv — comparable to several months of background radiation, and cumulative if you have had prior imaging.
- Additional cost: CT scans for robotic surgical planning in India typically cost between ₹8,000 and ₹15,000, charged separately from the surgery cost itself.
- Waiting period of 1–2 weeks: Once the scan is completed, the data must be processed and loaded into the robot's planning software before your surgical date can be confirmed.
Beyond logistics and cost, there is a clinical limitation that CT-based planning cannot resolve: the problem of temporal mismatch. Your CT scan creates a model of your knee as it was on the day of the scan. But on the morning of surgery — which may be 10 to 14 days later — your knee's soft tissue tension, ligament laxity, and cartilage state will not be identical. The robot, however, is still executing a plan based on that older snapshot.
A static plan cannot adapt to a dynamic body. This is not a flaw in any surgeon's skill — it is a fundamental limitation of any system that locks its plan before the patient is on the table.
How VELYS Maps Your Knee in Real-Time: Step by Step
Understanding the VELYS intraoperative process demystifies what "real-time registration" looks like in practice. This is a structured, surgeon-guided sequence that happens inside the operating theatre, before the first bone cut is made.
Anatomical Landmark Registration
Using specialised tracked probes, key anatomical landmarks are identified: the femoral condyles, tibial plateau, hip centre of rotation, and ankle joint. The robot's infrared optical tracking system captures these landmarks with sub-millimetre precision — with the patient already anaesthetised and positioned, meaning the knee is in its true surgical state.
Intraoperative 3D Model Construction
VELYS's software uses the registered landmarks to instantly construct a three-dimensional model of your knee — not a generic template, not a pre-operative approximation, but a model built from your actual bony anatomy as it exists in the theatre. The surgeon reviews this model before proceeding.
Dynamic Ligament Balance Testing
This is the step that sets VELYS apart from competing systems. Before any bone is cut, the surgeon uses the robot to test ligament balance dynamically across the full range of knee flexion. The system provides real-time data on gap symmetry and tension, allowing implant size and positioning to be fine-tuned to achieve optimal soft tissue equilibrium — with your actual ligaments, under actual surgical conditions.
Robotic Arm Executes Precision Bone Cuts
Only after landmark registration, model construction, and ligament balancing are complete does the robotic arm begin executing bone cuts. It operates within surgeon-defined, sub-millimetre boundaries — meaning it physically cannot cut beyond the planned zone. The result: implant fit tuned to your soft tissue tension as it exists at that exact moment in the OR.
Head-to-Head: VELYS vs Mako vs ROSA
Here is a direct, factual comparison of the three major robotic knee replacement systems available in India — including the one available right here in Ahmedabad at DHS Hospital.
| Feature | VELYS (DHS Hospital, Ahmedabad) |
Mako (Stryker) |
ROSA (Zimmer Biomet) |
|---|---|---|---|
| Pre-op CT scan required | No ✓ | Yes | Yes |
| Pre-op CT scan cost | ₹0 | ₹8,000–₹15,000 | ₹8,000–₹15,000 |
| Radiation exposure | None ✓ | Yes | Yes |
| Real-time soft tissue balancing | Yes — Dynamic ✓ | Limited | Limited |
| Intraoperative anatomy registration | Yes ✓ | No (pre-planned) | No (pre-planned) |
| Paired implant system | J&J Attune | Stryker Triathlon | Zimmer Persona |
| Pre-op surgical scheduling delay | None — Surgery in days | 1–2 weeks (scan processing) | 1–2 weeks (scan processing) |
| Available in Ahmedabad | DHS Hospital ✓ | Other centres | Other centres |
Is Imageless Surgery Right for Me? Your Questions Answered
Does "imageless" mean less accurate?
No — and this is the most common misconception. Imageless means no CT scan is required, not less precise. VELYS achieves sub-millimetre accuracy by registering your actual bone anatomy intraoperatively. The result is a surgical plan based on your knee as it truly exists on the day of surgery — not a scan taken weeks earlier.
What if my knee anatomy is unusual or severely deformed?
Severe deformity cases — including varus (bow-leg) and valgus (knock-knee) deformities — are assessed individually by Dr. Hardik Shah. The large majority of such cases are entirely suitable for VELYS. Your suitability is confirmed at your consultation with clinical examination and standard X-rays. No CT scan is needed for this assessment either.
Is VELYS suitable for partial knee replacement?
VELYS is designed for total knee replacement, paired with the J&J Attune system. Whether partial or total knee replacement is appropriate for your case depends on which compartments of your knee are affected — a decision made during your consultation based on your X-rays, activity goals, and clinical presentation.
Does the imageless approach change which implant is used?
No. VELYS pairs with the J&J Attune — a globally proven, widely used implant with extensive long-term outcome data. The imageless approach enhances how accurately the implant is placed, not which implant is used.
How does real-time ligament balancing improve long-term outcomes?
Correct ligament tension at the time of implantation reduces uneven wear on the polyethylene bearing surface, improves knee range of motion, reduces stiffness, and decreases the risk of requiring revision surgery years later. VELYS allows Dr. Shah to test and achieve this balance dynamically — testing multiple positions and adjusting in real time — before the final implant components are secured.
Why Dr. Hardik Shah Chose VELYS for DHS Hospital
When DHS Multispecialty Hospital decided to invest in robotic knee replacement technology, Dr. Hardik M Shah evaluated multiple platforms — including CT-based systems — before recommending VELYS. His criteria were clear:
- Patient safety: No extra radiation burden on already-medically-complex patients
- Workflow efficiency: No pre-op CT delays — patients get to surgery faster when they need it
- Intraoperative adaptability: Real-time balancing, not a static pre-planned blueprint
- Proven clinical outcomes: VELYS paired with J&J Attune carries extensive independent outcome data
- Surgeon empowerment: VELYS enhances surgical judgment — it does not replace it
With over 2,000 knee surgeries performed across his career, Dr. Shah has operated with conventional techniques, navigation systems, and now robotic assistance. His conclusion: VELYS gives patients the most personalised, real-time surgical plan possible — and that matters most in a procedure designed to last 20+ years.
📖 Related Guides from DHS Hospital:
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About the Author
Dr. Hardik M Shah is the lead orthopedic surgeon at DHS Multispecialty Hospital, Gurukul, Ahmedabad. He holds MBBS (Gold Medal), MS Orthopedic Surgery, and FRCS (Germany). With 14+ years of experience and over 2,000 knee surgeries, Dr. Shah brought VELYS imageless robotic knee replacement technology to Gujarat.
Medically reviewed by: Dr. Swagat M Shah, MS Ortho, DNB Ortho, FIAAS (UK) — DHS Multispecialty Hospital, Ahmedabad.