Who is a candidate for Mako robotic TKR

The question most patients ask first is straightforward: is this operation actually for me? Mako robotic-arm assisted total knee replacement is indicated for adults with mid-to-late stage knee osteoarthritis — typically those in whom the disease has progressed across multiple compartments and where conservative measures, including physiotherapy, weight management, and injection-based treatments, have not provided adequate or lasting relief.

The candidacy criteria are the same as for conventional total knee replacement. A surgeon will consider overall health, bone quality, body mass index, and whether the patient has realistic expectations about recovery and long-term function. Robotic assistance does not alter these thresholds. Patients who fall outside the criteria for a knee replacement are not brought within them simply because the surgery uses a robotic arm.

It is important to understand what Mako is — and what it is not. It is a precision tool that refines how the implant is positioned during surgery; it is not a separate clinical indication or a distinct operation. The decision that a knee replacement is appropriate comes first, made on clinical grounds in the usual way. The robotic element addresses the execution of that decision, not the eligibility for it.

A consultant assessment remains the necessary starting point to determine whether TKR — with or without robotic assistance — is the right next step for any individual patient.

The pre-operative CT scan and personalised surgical plan

Before any incision is made, Mako TKR requires a planning step that conventional knee replacement does not: a dedicated CT scan of the entire lower limb, from hip to ankle. This scan — distinct from the MRI or X-rays used to diagnose osteoarthritis — is typically arranged several weeks before the operative date and takes around 30 minutes. Patients should expect it as a separate appointment, not something that happens on the day of surgery.

Once acquired, the scan data is loaded into the Mako system by a specialist who contours the bone surfaces to generate a patient-specific 3D anatomical model. This is not a generic template: it reflects that individual's own bone geometry, so the model used to plan one patient's operation will differ from every other.

The surgeon then works through this virtual model before theatre, adjusting the planned bone cuts, selecting the appropriate implant size, and defining its precise orientation and alignment. By the time the patient arrives for their operation, the implant positioning has already been decided — the 3D plan is loaded into the Mako system and guides the procedure intraoperatively.

It is worth being clear about what this step represents. The pre-operative plan is a precision-planning tool; it is designed to reduce variability in how the implant is placed, not a promise of any particular outcome. Individual results still depend on patient health, bone quality, and rehabilitation. That said, the plan being established before any cut is made is the central technical distinction between Mako TKR and a conventional approach.

What the consent discussion covers

Arriving at the consent appointment already familiar with the key discussion points makes the conversation significantly more productive. For Mako TKR, the consent discussion typically covers four areas.

Procedure mechanics. The robotic arm does not operate independently at any point. The surgeon makes every clinical decision, guides the arm throughout, and can override the system. What Mako provides is a haptic boundary — a physical resistance that prevents cutting outside the zone defined in the pre-operative plan. Control remains entirely with the surgical team.

Clinical rationale. The consent discussion will explain why a personalised approach is used: targeted removal of diseased bone while sparing healthy tissue, and implant positioning calibrated to that patient's own anatomy rather than a population average.

Standard surgical risks. Robotic assistance does not eliminate the risks common to all total knee replacement. These include infection, bleeding, deep vein thrombosis or pulmonary embolism, nerve or vessel injury, and implant loosening over time. Patients should expect these to be discussed explicitly — the robotic element refines how the surgery is executed, not whether these risks exist.

CT radiation exposure. Because Mako planning requires a pre-operative CT scan (covered in the previous section), patients are exposed to a small additional radiation dose beyond standard diagnostic imaging. This is a pathway-specific consideration that should be raised during consent.

Consent documentation requirements vary between hospitals and jurisdictions. Asking the surgical team for written patient information sheets ahead of the consent appointment — rather than reading them for the first time on the day — is a reasonable step.

What happens on the day of surgery

Surgery day divides neatly into a pre-theatre preparation phase and the procedure itself — and knowing what each involves tends to reduce the anxiety that builds in the hours beforehand.

Arriving and preparing

Patients typically report to the ward 1.5–2 hours before their scheduled start time. During this window, a nurse places an intravenous line for fluids and administers prophylactic antibiotics, and the anaesthesiologist visits to confirm the pain management plan. For Mako TKR the standard anaesthetic regime is specific: spinal anaesthesia (numbness from the waist down) combined with an adductor canal or femoral nerve block. The nerve block is particularly worth noting — it provides targeted pain relief around the knee that can last for several days post-operatively, which is one reason early mobilisation is possible. Light sedation keeps patients relaxed and unaware during the procedure without requiring a full general anaesthetic in most cases.

In theatre

Once in the operating room, small tracking arrays are temporarily secured to the thigh and shin bones. These act in a similar way to GPS markers, relaying the precise position and orientation of the knee to the Mako computer in real time. Patients may notice them as part of the set-up; they are removed before the wound is closed.

The surgeon makes a 4–6 inch incision to expose the joint and then guides the robotic arm to remove the diseased bone and cartilage. AccuStop™ haptic technology provides physical resistance whenever the arm approaches the edge of the pre-planned cutting zone — the system pushes back, making it considerably harder to stray outside that boundary. Throughout the resection, the Mako system also fuses the static CT-based plan with live joint-motion data captured intraoperatively, allowing the surgeon to fine-tune ligament balance in real time. This dynamic adjustment is not available in conventional total knee replacement.

Once bone preparation is complete, trial implant components are inserted and the knee is put through a range of motion to confirm balance before the final metal-and-polyethylene Triathlon Total Knee implant is cemented in place and the wound closed.

The overall procedure typically takes longer than conventional TKR — a 2026 bilateral comparative study recorded a mean operative time of around 105 minutes for robotic TKA versus 81 minutes for conventional. This additional time reflects the precision set-up and real-time verification steps rather than any complication.

Recovery in hospital and the discharge process

Recovery from Mako TKR begins in the theatre's immediate aftermath rather than the morning after. A physiotherapist helps the patient stand, walk a short distance with a walking frame, and start range-of-motion exercises on the same day as surgery — typically within a few hours of leaving the recovery area. This early mobilisation is a deliberate clinical priority, not an ambitious target reserved for the fittest patients.

The inpatient stay

Most patients spend one to two nights on the ward; a third night is sometimes needed depending on how recovery progresses and what level of support is available at home. What determines the moment of discharge is not how many days have elapsed but whether a set of functional milestones have been reached:

• Pain managed adequately on oral medication alone
• Safe, independent transfers in and out of bed
• Walking-frame ambulation over a meaningful distance
• Ability to navigate stairs with supervision
• Stable observations and wound healing without signs of infection
• Confirmed home support in place

When each of these criteria is met — and only then — the surgical team will clear the patient to leave.

Leaving hospital

The discharge pack provides a structured pathway for the weeks ahead: prescriptions for an analgesic and an anticoagulant to reduce DVT risk, a home physiotherapy protocol, and a follow-up appointment typically scheduled two to six weeks post-operatively. That structure is worth emphasising — discharge marks the start of a supported recovery, not the end of clinical oversight.

Same-day discharge is possible in selected cases, though it is more commonly associated with partial Mako procedures than with full TKR. Individual suitability depends on functional progress, home circumstances, and the surgical team's assessment — a conversation worth having before the operation rather than on the day itself.

What the clinical evidence shows about Mako TKR outcomes

The evidence base for Mako robotic TKR is encouraging in places but still maturing — and reading it accurately means holding both truths at once.

Methodologically, the strongest data come from bilateral staged studies, where each patient receives robotic TKR in one knee and conventional TKR in the other, removing most of the individual variation that confounds standard comparisons. In a 55-patient cohort (Mulpur 2022), robotic-assisted TKA produced significantly higher patient satisfaction, faster independent ambulation, and patients rated the robotic knee as less painful and more natural than the conventional side (p<0.01). The Forgotten Joint Score — which measures how unobtrusive the replaced joint feels in daily life — was also statistically higher after robotic surgery (mean 73.0 versus 70.3, p<0.01). A meaningful caveat applies here: that absolute margin falls below the minimal clinically important difference, meaning the statistical signal does not straightforwardly translate to a perceptible everyday benefit. Oxford Knee Scores were comparable between groups.

Broadening the lens moderates the picture further. A 2024 systematic meta-analysis found no pooled statistically significant satisfaction advantage for robotic TKA across all included studies — a finding that counsels against generalising individual positive results to all patients or all settings.

Within the Mako platform, alignment strategy appears to influence outcomes independently of the robotic approach itself. Functional alignment produced better short-term scores on multiple patient-reported measures and substantially lower rates of residual instability (6.4% versus 21.9%) compared with adjusted mechanical alignment.

One gap is worth naming explicitly: Mako-specific implant survivorship data at ten years or beyond are not yet established in the published literature. Mako is best understood as a precision aid that improves the consistency of implant positioning — with an outcome evidence base that is promising but still developing.

1. [1] Outcomes of Bilateral Staged TKA in Patients Who Underwent both Conventional TKA and Robotic TKA: A Single Surgeon's Experience. (2026). https://doi.org/10.52965/001c.160598 https://doi.org/10.52965/001c.160598
2. [2] Short-term functional outcomes of robotic-assisted TKA are better with functional alignment compared to adjusted mechanical alignment. (2024). https://doi.org/10.1051/sicotj/2024002 https://doi.org/10.1051/sicotj/2024002