Approach Techniques in Knee Replacement

Approach Techniques in Knee Replacement

When a surgeon performs a knee replacement, one of the first decisions is how to access the knee joint itself. This decision is called the surgical approach. The approach determines which muscles and tendons are affected during surgery, and it directly influences how quickly a patient recovers strength, motion, and comfort after the procedure.

There are three primary approach techniques used in knee replacement surgery today: the medial parapatellar approach, the midvastus approach, and the subvastus approach. All three enter the knee from the medial (inner) side. The key difference between them is how much of the quadriceps muscle and tendon is disrupted during the surgery. A fourth option, the lateral approach, enters the knee from the outer side and is discussed later in this article.

These differences are important because the quadriceps is the primary muscle responsible for straightening your leg, supporting your body weight, and controlling your knee during activities like walking, climbing stairs, and rising from a chair.

Each approach has its own history in the medical literature, with its own set of advantages and considerations. Before we discuss them individually, it helps to understand a bit about the anatomy involved.

The Quadriceps and the Extensor Mechanism

The quadriceps is a group of four muscles on the front of your thigh. These muscles merge together into the quadriceps tendon, which attaches to the top of the kneecap (patella). From the bottom of the kneecap, the patellar tendon connects to the tibia (shin bone). This entire system, including the quadriceps muscles, the quadriceps tendon, the kneecap, and the patellar tendon is called the extensor mechanism. It is the engine that powers your knee.

The muscle most relevant to the surgical approach is the vastus medialis oblique (VMO), the innermost muscle of the quadriceps group. It sits on the inner (medial) side of the thigh and attaches to the inner border of the kneecap. The VMO plays an important role in stabilizing the kneecap during movement and is critical for the final degrees of straightening the leg. How the surgeon manages this muscle during surgery is the essential difference between the three medial approaches.

The Medial Parapatellar Approach: The Traditional Standard

The medial parapatellar approach is the most commonly used surgical approach for knee replacement worldwide, accounting for over 90% of procedures. First described by the German surgeon Bernhard von Langenbeck in 1878, it was later modified and popularized by Dr. John Insall in 1971. Insall's refinements made the approach the cornerstone of modern knee replacement surgery, and it has remained the gold standard for decades.

In this approach, the surgeon makes a midline skin incision over the front of the knee. The deeper incision then cuts through the VMO attachment to the quadriceps tendon, then down the inner border of the kneecap, continues along the medial side of the patella, and extends down to the top of the shin bone at the tibial tuberosity. This provides excellent exposure of the entire knee joint. The patella is then moved to the side (everted or subluxated laterally), giving the surgeon a wide, clear view of the bones and ligaments.

The primary advantage of the medial parapatellar approach is its excellent exposure. It is technically the easiest approach to perform, making it highly reproducible across surgeons of all experience levels. It is versatile enough to accommodate all knee deformities and body types in a straight forward manner.

However, this approach does require cutting through the quadriceps tendon/mucle and separating the VMO muscle from its attachment. After the surgery is completed, the surgeon will repair these structures by suturing the quadriceps tendon and VMO back together. This disruption of the extensor mechanism can delay the recovery of quadriceps strength after surgery, and patients may take longer to achieve a straight leg raise: the ability to lift the leg while keeping the knee straight, which is an important early milestone in recovery.

Additionally, by cutting through the tendon, the medial parapatellar approach may disrupt some of the blood supply to the kneecap, which has led some surgeons to explore alternative approaches that better preserve the patellar circulation and the extensor mechanism.

The Subvastus Approach: Preserving the Entire Quadriceps

The subvastus approach takes a fundamentally different path to the knee joint. Rather than cutting through the quadriceps tendon, the surgeon enters the knee from below the VMO muscle, lifting it upward to access the joint. This preserves the entire quadriceps mechanism intact. No muscle is cut and no tendon is divided.

This technique has a long history. It was first described by the German surgeon F. Erkes in 1929, who designed a physiological incision that avoided violating the quadriceps mechanism. Despite its early origins, the approach was not widely adopted and faded from the literature for decades. It was reintroduced to the modern era by Dr. Aaron A. Hofmann in 1991, who published his experience using the "Southern" subvastus approach for primary total knee arthroplasty. Hofmann demonstrated that the approach preserved the integrity of the extensor mechanism and maintained the blood supply to the kneecap, offering meaningful recovery advantages.

The subvastus approach may use the same midline skin incision or a modified incision that is angulated more medially. This modified incision can allow the surgeon to access the deeper structures by avoiding subcutaneous dissection or the creation of skin flaps, especially when the approach is performed in extension.

The deeper dissection then follows a different path than the medial parapatella approach: instead of incising the quadriceps tendon, the surgeon identifies the lower border of the VMO muscle, then mobilizes the muscle followed by a gentle lifting of the muscle off of the intermuscular septum. A capsular incision is then made just deep to the muscle, and the patella is subluxated laterally (moved to the side without flipping it over).

Because the quadriceps mechanism remains completely intact, research has consistently shown several early postoperative advantages. Studies demonstrate that patients who undergo the subvastus approach achieve a straight leg raise sooner (often within 1–3 days versus 4–6 days with the medial parapatellar approach), experience less postoperative pain, require fewer narcotic pain medications, and have less blood loss during surgery. Improved patellar tracking has also been documented, with fewer patients needing a lateral retinacular release (a secondary procedure to correct kneecap alignment). A landmark randomized trial by Roysam and Oakley (2001) showed patients achieved a straight leg raise nearly twice as fast and had significantly greater knee flexion at one week compared to the standard approach.

The subvastus approach is considered technically more demanding than the medial parapatellar approach. In some patients, it requires more work to achieve the same exposure. The approach may require a few extra minutes of surgical time, particularly in the surgeon's early experience with the technique. Historically, some authors cited obesity, severe deformity, and stiff knees as relative contraindications. However, experienced subvastus surgeons have demonstrated success across all patient types, including those with a body mass index over 40 and those with limited preoperative range of motion. Large series have reported that 99% of primary knee replacements can be performed through the subvastus approach. It is possible that previous extensive surgeries on the knee, could limit this exposure and require a more traditional exposure.

One additional benefit of this approach is that it tends to better preserve the blood supply to the kneecap, since the superior and inferior medial genicular arteries are generally left undisturbed. This is a meaningful consideration because a compromised blood supply can contribute to complications such as patellar fracture or avascular necrosis of the patella.

The Midvastus Approach: A Compromise Between the Two

The midvastus approach was developed as a middle ground between the excellent exposure of the medial parapatellar approach and the muscle-sparing philosophy of the subvastus approach. It was first described by Dr. Gerard Engh in 1997.

In the midvastus approach, the surgeon makes the same midline skin incision and then, rather than cutting through the quadriceps tendon (as in the medial parapatellar approach) or entering entirely beneath the VMO muscle (as in the subvastus approach), the surgeon splits the VMO muscle fibers along their natural direction. This split typically extends approximately 2–4 centimeters into the muscle belly from the upper border of the kneecap. The muscle fibers are separated by blunt dissection, allowing the surgeon to reach the joint capsule and enter the knee.

Engh's original 1997 study randomized 118 consecutive knee replacements to either the midvastus or medial parapatellar approach and found that the midvastus provided equivalent exposure with improved patellar stability. Research comparing the midvastus approach to the medial parapatellar approach has generally shown advantages in the early recovery period, including reduced pain at one to two weeks, faster return of quadriceps strength, and improved early range of motion. A randomized double-blinded study by Bäthis and colleagues (2005) found that midvastus patients demonstrated significantly lower pain scores and superior quadriceps strength at three and six weeks compared to the medial parapatellar approach.

The midvastus approach offers easier surgical exposure than the subvastus approach, making it somewhat more accessible to surgeons transitioning away from the traditional medial parapatellar technique. However, because it does involve splitting through the VMO muscle, it does not completely preserve the extensor mechanism in the way that the subvastus approach does. The split may also affect some of the nerve supply to the VMO, though this has not been shown to have significant long-term clinical consequences.

The midvastus approach has been used in both standard and minimally invasive versions (the "mini-midvastus"), with the mini version limiting the skin incision and the depth of the VMO split. Some studies have shown that the mini-midvastus approach can improve knee awareness scores (the Forgotten Joint Score), suggesting that patients may be more likely to "forget" their replaced joint during daily activities.

Comparing the Three Medial Approaches: What the Research Shows

Multiple meta-analyses and systematic reviews have compared these three approaches. The largest of these, published in the Journal of Arthroplasty, pooled data from 32 randomized controlled trials involving over 2,400 knee replacements. The overall findings can be summarized as follows:

Early recovery advantages. Both the subvastus and midvastus approaches show advantages over the medial parapatellar approach in the first one to six weeks after surgery. These include faster return of quadriceps strength, earlier straight leg raise, improved early range of motion, and reduced pain. A 2023 network meta-analysis by Stubnya and colleagues found that the subvastus approach performed best for range of motion improvement across multiple early postoperative time points.

Long-term outcomes are comparable. At six months, one year, and beyond, functional scores (Knee Society Score, WOMAC) and range of motion converge across all three approaches. No approach has been shown to produce superior long-term results over another.

Operative time. The medial parapatellar approach is typically considered the fastest. The subvastus approach may initially require a few extra minutes, though this difference diminishes significantly with surgeon experience. In high-volume series, total operative times have been shown to eventually become equivalent or even possibly faster with the subvastus approach in some patients.

Lateral retinacular release. The subvastus approach is associated with a significantly reduced need for lateral retinacular release compared to the medial parapatellar approach. This suggests improved patellar tracking when the extensor mechanism is preserved.

Complication rates. Complication rates are similar across all three medial approaches. No approach has been associated with a higher rate of component malalignment, implant loosening, or other adverse events.

Registry data. A 2021 study by Blom and colleagues, analyzing National Joint Registry data from England and Wales covering over 875,000 knee replacements, found that the midvastus approach was associated with a 20% reduced risk of revision surgery compared to the medial parapatellar approach, though this finding requires further validation. The subvastus approach was used in approximately 1% of cases and the midvastus in approximately 3%, with the medial parapatellar approach accounting for over 91%.

Why Aren't the Muscle-Sparing Approaches Used More Often?

Given the documented early recovery advantages of the subvastus and midvastus approaches, it is reasonable to ask why they remain relatively uncommon. Several factors contribute to this.

First, surgeon training is a major factor. The medial parapatellar approach has been the dominant technique taught in orthopedic residencies and fellowship programs for decades. Many surgeons are highly proficient with it and may be reluctant to adopt a new technique that has a learning curve.

Second, the subvastus approach in particular does require more surgical experience to manage exposure, especially in patients with large body habitus or stiff knees. Surgeons who try the technique in a few cases and find the exposure challenging may return to the more familiar medial parapatellar approach.

Third, the long-term outcomes are comparable across all three approaches, which may reduce the perceived urgency to change. Surgeons who are achieving excellent results with the medial parapatellar approach may view the short-term benefits of alternative approaches as incremental.

However, with the growing emphasis on rapid recovery protocols, outpatient surgery, and patient satisfaction, interest in the muscle-sparing approaches has been increasing. The combination of the subvastus approach with robotic-assisted technology is also gaining attention to maximize all aspects of patient recovery.

The Lateral Approach: An Emerging Alternative

The three approaches discussed above all share a common feature: they enter the knee from the medial (inner) side. There is, however, a fundamentally different way to access the knee joint: from the lateral (outer) side. There are several variants of this approach described. This includes an approach that incices through the the outer (lateral) part of the patella (knee cap), called the lateral parapatella approach. In the other version, the knee is accessed from underneath the lateral quadriceps, called the subvastus lateral approach.

The lateral parapatellar approach was first described by Dr. Peter Keblish in 1991. Keblish designed this approach specifically for patients with a valgus (knock-kneed) deformity. This approach involves dividing the tendinous attachment of the vastus lateralis (the outer quadriceps muscle) from the extensor mechanism, rather than cutting through the muscle fibers themselves. In patients with more severe knock-knee deformity, the surgeon may need to lengthen this tendinous tissue to achieve proper alignment.

Since mechanically aligned valgus knees would commonly require release of contracted lateral structures in patients with significant knock knee deformity this approach provides direct access to these structures. Keep in mind that the need for these releases have significantly lessened with the development of alternative alignment techniques and the introduction of robotic systems.

By entering from the lateral side, the surgeon gains direct access to these tight structures, which can make balancing the knee more straightforward when performed with mechanical alignment. The approach also preserves the medial blood supply to the kneecap and can improve patellar tracking.

In 2025, Andriollo, Lustig, and colleagues from Lyon, France published the first surgical technique describing the integration of this lateral parapatellar approach with the Mako robotic system for valgus knee deformities, discussed further below.

For the past three decades, the lateral approach has been used selectively — primarily for patients with significant valgus deformities, which represent approximately 10 to 15 percent of all knee replacement patients. Multiple studies have shown favorable results in this specific sub-group, including deformity correction, better patellar tracking compared to performing a medial parapatella approach, especially if extensive lateral releases are necessary with a mechanically aligned knee.

The approach has also been modified over the years, with some versions requiring cutting the insertion of the iliotibial band and/or cutting through the bone at its insertion site. Some approaces snip the quadriceps tendon and require a lengthening of the lateral tissues.

However, the technique has remained niche. Most surgeons are trained through medial approaches, and the lateral approach is considered technically more demanding, with different closure considerations due to the thinner soft tissue coverage on the outside of the knee.

More recently, some surgeons have begun exploring whether a lateral approach could be used more broadly and not just for valgus knees, regardless of the patient's alignment. This concept builds on the idea that entering from the lateral side can spare the quadriceps mechanism entirely (similar to the medial subvastus approach) while also potentially avoiding disruption of the saphenous nerve and the medial soft tissue structures.

One important clinical study supporting the subvastus version of the lateral approach as a universal technique comes from a single-center retrospective study published in 2023 by Nguyen and colleagues, who reviewed 931 consecutive knee replacements performed through a lateral subvastus approach at one practice in Orlando, Florida. All patients, regardless of the preoperative alignment, received the same lateral approach. The study reported that patients across all alignment groups achieved similar improvements in range of motion and Knee Society Scores by six weeks, with outcomes remaining stable at one and two years. The authors also reported high patient satisfaction and a notable ability for patients to kneel after surgery.

This clinical study was supported by earlier foundational work. A 2007 pilot study by Dr. Michael Mont described a minimally invasive direct lateral approach in 35 patients, showing promising quadriceps recovery and reduced anterior knee pain. However, that study also identified a notable complication rate, which the authors attributed to using standard instruments and implants that had not been designed for lateral entry. Separately, Dr. Brent Lanting's group at Western University in Ontario, Canada, conducted two independent cadaveric studies (2020) that found comparable surgical exposure and knee kinematics between the lateral subvastus approach and the standard medial parapatellar approach, though the cadaveric work also noted a risk of iatrogenic soft tissue injury to the vastus lateralis and surrounding ligaments.

The first independent clinical comparison of the lateral approach to a medial approach was published in 2023 by the Lanting group at Western University in Canada, the same team that conducted the cadaveric studies described above. In a small study of 27 patients, they compared the lateral subvastus approach to the standard medial parapatellar approach in patients with neutral or varus alignment. While both groups improved after surgery, the medial parapatellar group showed significantly greater improvement in Knee Society knee scores at three months, one year, and two years. Other outcome measures, including the WOMAC and SF-12, were similar between groups. The authors concluded that further studies are needed to identify any benefits the lateral approach may offer.

There are several important considerations for patients researching this approach.

First, the clinical evidence is still in its early stages. The 931-case study represents one practice using one proprietary implant system (the Optimotion Total Knee System), reviewed retrospectively over a one-to-two-year follow-up period. There are currently no randomized controlled trials comparing the lateral approach to the medial approaches and no meta-analyses. This stands in contrast to the three medial approaches, which are supported by decades of randomized trials and multiple systematic reviews. Independent long-term data will be needed to fully evaluate the durability and safety of this technique as a universal approach.

Second, the lateral approach currently requires specialized instrumentation. The Optimotion Implant System is, at present, the only total knee system designed specifically for lateral entry. Standard knee replacement instruments are designed for medial approaches, and Mont's earlier pilot study demonstrated that attempting a lateral approach with standard equipment can lead to complications. This means the approach is currently tied to a specific implant system and cannot be performed with the instruments most surgeons use in their practices.

Third, the major robotic-assisted surgical platforms used in knee replacement, such as VELYS and Mako, are engineered for medial surgical access. Their workflows, cutting boundaries, and registration processes are all built around medial exposure. In 2025, Andriollo, Lustig, and colleagues published the first surgical technique describing an adaptation of the Mako robotic system for use with a lateral parapatellar approach in valgus knees. This represents an important proof of concept, but several qualifications are worth noting. The technique required modifications to the standard robotic workflow, including altered femoral pin placement and an extended cutting boundary protocol for the tibial resection. The authors identified specific surgical risks, including potential injury to the patellar tendon during the tibial cut, femoral component malpositioning, and excessive lateral rotation of the tibial component — challenges that arise from adapting a system designed for medial entry to lateral exposure. No patient outcomes, complication rates, or follow-up data were reported; this was a technique description for valgus knees only. It is also important to note that this technique used the lateral parapatellar approach, the Keblish method, not the lateral subvastus approach described in the Nguyen study above. There are currently no published data on integrating any robotic platform with the lateral subvastus approach, and no published data on using the VELYS system with any form of lateral entry. Robotic-assisted surgery continues to be increasingly adopted across the orthopedic community and offers documented benefits in precision and reproducibility, making this an area worth watching as it develops.

The lateral approach represents an innovative concept in knee replacement surgery: the idea that the knee can be accessed effectively from the outside while sparing the quadriceps mechanism. The early clinical results are encouraging, and the independent cadaveric research supports the anatomical feasibility of the technique. However, patients considering this approach should understand that it remains in the early chapters of its evidence story. As with any emerging surgical technique, the orthopedic community will be watching for independent replication, randomized trials, and longer-term follow-up data to determine where the lateral approach ultimately fits among the available options.

A Brief History of the Approach Techniques

1878: Bernhard von Langenbeck describes the original medial parapatellar approach to the knee, following the medial border of the quadriceps tendon and leaving a tissue cuff on the patella for repair.

1929: F. Erkes, a German surgeon, first describes the subvastus approach, designed to enter the knee without violating the quadriceps mechanism. The technique receives little attention in the English-language literature and is largely forgotten.

1971: John Insall publishes his midline approach to the knee, a modification of the medial parapatellar technique that becomes the standard for total knee arthroplasty. Insall's approach, combined with his pioneering implant designs, makes knee replacement one of the most successful procedures in modern surgery.

1991: Two significant developments occur in the same year. Aaron A. Hofmann reintroduces the subvastus approach for modern knee replacement at the University of Utah, demonstrating its ability to preserve the extensor mechanism and maintain patellar blood supply. Separately, Peter Keblish describes the lateral parapatellar approach for knee replacement in patients with valgus deformity, establishing the first systematic method for accessing the knee from the outer side.

1997: Gerard Engh introduces the midvastus muscle-splitting approach as a compromise between the exposure of the medial parapatellar approach and the muscle preservation of the subvastus approach.

2000s–present: Multiple randomized controlled trials and meta-analyses are published comparing the three medial approaches. Interest in minimally invasive and muscle-sparing techniques grows alongside advances in robotic-assisted technology, fast-track recovery programs, and personalized surgical philosophies. A lateral subvastus approach is proposed as a universal technique by some surgeons, though the evidence base remains early.

What This Means for You as a Patient

The surgical approach is one of several important decisions that your surgeon makes during knee replacement. While all approaches can produce excellent results, the way the surgeon accesses your knee does influence your early recovery experience — particularly how quickly you regain quadriceps strength, your initial pain levels, and how soon you can perform a straight leg raise.

If early recovery and muscle preservation are priorities for you, it is worth discussing whether a subvastus or midvastus approach might be appropriate for your situation. At the same time, it is important to recognize that surgeon experience with a particular technique is one of the strongest predictors of a good outcome. A surgeon who is highly skilled with the medial parapatellar approach will likely produce excellent results, just as a surgeon experienced with the subvastus approach will.

As with alignment techniques and implant selection, the approach technique is one piece of a larger puzzle. The combination of approach, alignment philosophy, implant design, and the surgeon's overall experience all contribute to the final result. Some approaches, like the three medial techniques, have extensive research histories spanning decades. Others, like the lateral approach, are newer and still building their evidence base. We encourage you to have an open conversation with your surgeon about how they approach the knee, why they prefer the technique they use, and how it fits into your overall surgical plan.

References

Hofmann, Plaster, and Murdock (1991): Subvastus (Southern) approach for primary total knee arthroplasty. The foundational study reintroducing the subvastus approach for modern TKA, demonstrating preservation of the extensor mechanism and patellar blood supply.

Keblish (1991): The lateral approach to the valgus knee. Surgical technique and analysis of 53 cases with over two-year follow-up evaluation. The original description of the lateral parapatellar approach for TKA in fixed valgus deformity.

Engh, Holt, and Parks (1997): A midvastus muscle-splitting approach for total knee arthroplasty. The original description of the midvastus approach, presenting a randomized comparison of 118 consecutive TKAs showing equivalent exposure with improved patellar stability.

Roysam and Oakley (2001): Subvastus approach for total knee arthroplasty. A prospective, randomized, observer-blinded trial of 89 knee arthroplasties demonstrating significantly earlier straight leg raise, lower opiate consumption, less blood loss, and greater early knee flexion with the subvastus approach.

Bäthis and colleagues (2005): Midvastus approach in total knee arthroplasty: a randomized, double-blinded study on early rehabilitation. A prospective, double-blinded, randomized study of 50 patients demonstrating significantly lower pain scores and superior quadriceps strength at three and six weeks with the midvastus approach compared to the medial parapatellar approach.

Seyler, Mont, and colleagues (2007): Minimally invasive lateral approach to total knee arthroplasty. A pilot study of 35 patients describing a direct lateral approach, with promising functional outcomes but a notable complication rate attributed to standard instrumentation not designed for lateral entry.

Teng and colleagues (2012): Subvastus versus medial parapatellar approach in total knee arthroplasty: meta-analysis. A meta-analysis of nine controlled trials involving 940 TKAs showing that the subvastus approach had significantly better Knee Society Scores at early and one-year follow-up, with reduced lateral retinacular release rates.

Liu and colleagues (2014): Surgical approaches in total knee arthroplasty: a meta-analysis comparing the midvastus and subvastus to the medial peripatellar approach. A comprehensive meta-analysis of 32 RCTs with 2,451 TKAs, finding that both the midvastus and subvastus approaches demonstrated early recovery advantages over the medial parapatellar approach.

Berstock and colleagues (2018): Medial subvastus versus the medial parapatellar approach for total knee replacement: a systematic review and meta-analysis of randomized controlled trials. A meta-analysis of 20 RCTs demonstrating early postoperative benefits of the subvastus approach with equivalence at longer follow-up.

Lanting and colleagues (2020): Lateral subvastus approach: A cadaveric examination of its potential for total knee arthroplasty. The first specimen-matched comparison of the lateral subvastus approach to the medial parapatellar approach, conducted independently at Western University, Canada.

Sidhu, Moslemian, Yamomo, Vakili, Kelly, Willing, and Lanting (2020): Lateral subvastus lateralis versus medial parapatellar approach for total knee arthroplasty: A cadaveric biomechanical study. A biomechanical study of 14 cadaveric knees comparing joint kinematics and laxity between the lateral subvastus and medial parapatellar approaches, finding no significant differences between groups, conducted independently at Western University, Canada.

Blom, Hunt, Matharu, Reed, and Whitehouse (2021): The effect of surgical approach in total knee replacement on outcomes. An analysis of 875,166 elective operations from the National Joint Registry for England, Wales, Northern Ireland and the Isle of Man. A registry analysis of over 875,000 knee replacements with up to 15 years of follow-up, finding that the conventional midvastus approach was associated with a 20% reduced risk of revision surgery compared to the medial parapatellar approach, while patient-reported outcome measures showed no clinically important differences between approaches.

Stubnya and colleagues (2023): Subvastus approach supporting fast-track total knee arthroplasty over the medial parapatellar approach: a systematic review and network meta-analysis. A network meta-analysis of 33 RCTs finding the subvastus approach performed best for range of motion improvement and that the mini-subvastus offered the greatest pain reduction in the early postoperative period.

Sidhu, Broberg, Willing, Teeter, and Lanting (2023): Lateral subvastus lateralis versus medial parapatellar approach for total knee arthroplasty: Patient outcomes and kinematics analysis. The first clinical outcomes comparison of the lateral subvastus approach to the medial parapatellar approach, from Western University, Canada. In a study of 27 patients, the medial parapatellar group demonstrated significantly greater improvements in Knee Society knee scores at multiple time points, while other functional measures were similar between groups.

Nguyen and colleagues (2023): Lateral subvastus approach to total knee arthroplasty: A novel surgical technique and retrospective review of 931 consecutive cases. The largest published clinical series of the lateral subvastus approach used as a universal technique across all knee deformity types, from a single center using a proprietary implant system.

Andriollo, Lustig, and colleagues (2025): Lateral approach in robotic total knee arthroplasty for valgus knees: A step-by-step technique. The first published surgical technique describing the integration of the Mako robotic system with a lateral parapatellar approach for valgus knee deformities, including a description of the required workflow modifications and identified surgical risks. No clinical outcomes were reported.

Mathew and colleagues (2025): Comparative study with 2-year follow-up on functional outcome of subvastus versus medial parapatellar approach in total knee arthroplasty. A randomized controlled trial of 300 patients showing the subvastus group achieved significantly quicker return of quadriceps function and shorter hospital stays, with comparable long-term outcomes at two years.

Scientific Committee from the Personalized Arthroplasty Society (PAS) (2025): Standardizing definitions of the total knee alignment techniques: recommendations by the Personalized Arthroplasty Society

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