Focalplasty for Resurfacing of Focal Articular Lesions of the Medial Femoral Condyle

Abstract

Background:

Focal osteochondral defects of the knee are difficult to manage, as untreated lesions may progress to early osteoarthritis. The OvertureTi Knee Resurfacing System is designed to treat focal defects while preserving native bone, cartilage, and soft tissue.

Indications:

Focalplasty is indicated in patients with compartmentalized cartilage lesions, preserved ligamentous stability, and meniscal integrity or repairable tears. Appropriate alignment, joint space preservation, and minimal osteophyte formation are required.

Technique Description:

The procedure began with arthroscopic repair of the medial meniscus root using a transtibial pull-out technique. Following this, an open approach was performed to expose the medial femoral condyle. The chondral defect was sized, and appropriate instrumentation was used to prepare the site. Cartilage scoring and sequential reaming were performed to achieve the desired depth and contour. Trial components were confirmed to fit and position, after which peg holes were drilled and filled with bone cement. Finally, the oblong OvertureTi femoral implant was seated flush with the surrounding cartilage surface, and standard wound closure was completed.

Results:

At 2 weeks, radiographs confirmed proper implant positioning. Long-term outcomes of the Overture prosthesis are not yet available. However, studies on similar implants, such as the HemiCAP, have reported improved function and survivorship at mid- to long-term follow-up.

Discussion/Conclusions:

The Overture prosthesis offers advantages over arthroplasty and biologic resurfacing, including lower cost, off-the-shelf availability, preservation of native tissues, and bone conservation for future arthroplasty. Larger prospective studies are required to determine its long-term clinical efficacy.

Patient Consent Disclosure Statement:

The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.

Graphical Abstract.

This is a visual representation of the abstract.

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DOI: 10.1177/26350254261429887.M1

Video Transcript

The following video demonstrates a focalplasty procedure for resurfacing a focal articular lesion of the medial femoral condyle in the knee.

Background

Osteochondral defects of the knee are focal lesions involving both articular cartilage and the underlying subchondral bone, most often in the femoral condyles, patella, or trochlea. ² They may arise from trauma, repetitive stress, or osteochondritis dissecans, causing pain, swelling, and mechanical symptoms. ² As articular cartilage has poor healing potential, untreated defects tend to progress to early osteoarthritis. ⁴ Diagnosis relies on clinical evaluation and imaging, particularly magnetic resonance imaging, while treatment ranges from conservative measures to surgical options, such as microfracture, osteochondral allograft transplantation, autologous chondrocyte implantation, or, more recently introduced, resurfacing techniques such as focalplasty.^1,5,9

The OvertureTi Knee Resurfacing System (Overture Orthopaedics) is a partial knee resurfacing implant designed to treat focal cartilage and osteochondral defects in a single compartment of the knee. The procedure, often referred to as focalplasty, preserves healthy bone, cartilage, and soft tissue. The system features 3-dimensional-printed porous titanium baseplates to promote osseointegration and titanium nitride femoral components. By targeting only the damaged area, Overture focalplasty aims to relieve pain, restore function, and preserve more natural knee kinematics compared to full joint replacement. ²

We discuss the case of a 69-year-old woman who presents with chronic right knee pain. The patient reported that the symptoms began 3 months ago after a workout and had since depended on crutches for ambulation. She referred to achy, dull medial knee pain, rated 6 out of 10, which exacerbated with prolonged weightbearing. Despite attempts at conservative management with physical therapy, nonsteroidal anti-inflammatory drugs, and intra-articular injections, her symptoms persisted. The patient denied associated swelling, catching, locking, or instability.

On physical examination, the patient ambulated assisted by crutches with an antalgic gait. The right knee showed mild effusion, extension to −2° and flexion to 130°, with 5/5 strength. Tenderness was noted over the medial joint line, with a positive medial McMurray test. Lachman, posterior drawer, and pivot shift were negative. Valgus and varus stress tests revealed no laxity. Distal neurovascular status was intact.

Preoperative radiographs of the right knee—including anteroposterior, flexion weightbearing, lateral, and sunrise views—showed well-preserved joint spaces in the medial, lateral, and patellofemoral compartments. The mechanical axis was normal, and no fractures or foreign bodies were identified.

Preoperative magnetic resonance imaging demonstrated a medial meniscus root tear along with chondral defects of the medial femoral condyle.

Indications

When considering focalplasty, the ideal candidate should meet several key criteria. First, the meniscus should either be intact or have a tear that is amenable to repair. (1) The collateral and cruciate ligaments must be competent to ensure a stable joint. (2) Cartilage loss should be focal and limited to a single compartment, rather than widespread. (3) Radiographically, we look for preserved joint space in the involved compartment, indicating that the degeneration is localized. Finally, (4) the mechanical axis of the limb should fall within the central 75% of the affected compartment, as alignment close to neutral helps maintain proper load distribution and implant longevity.

Technique Description

The patient is positioned supine on the operating table. A high thigh tourniquet is applied. Examination under anesthesia demonstrated stable ligaments. The operative side is prepared and draped in the usual sterile manner, and standard portals are established before knee arthroscopy.

A medial meniscal posterior root tear was identified, and the tear was repaired using a double-tunnel transtibial pull-out technique, with tibial fixation using a 5.5-mm polyetheretherketone (PEEK) anchor (Smith & Nephew).

The procedure is then converted to a mini-open approach via a medial parapatellar arthrotomy. A longitudinal incision is made along the medial border of the patellar tendon by extending the anteromedial portal incision. The periosteum and soft tissues of the proximal medial tibia are carefully elevated and dissected medially, with particular attention to preserving the superficial medial collateral ligament. The Z retractors are then positioned to provide adequate exposure, and the cartilage defect is inspected with the knee in flexion.

Implants are available in round and oblong shapes, and the selection is based on the size of the defect. In this case, an oblong implant was chosen. The femoral oblong pin sizer is then used to confirm the appropriate implant size. It should extend beyond the defect to ensure complete coverage and be positioned perpendicular to the femoral surface. The sizer must sit flush; if not, it should be readjusted or a different size selected, prioritizing full contact in the areas of greatest articulation. ¹

Once the femoral oblong pin sizer is positioned flush with the native cartilage surface, the pin is advanced through the superior hole until the laser mark aligns with the handle. The inferior pin is then placed to mark the sizer's orientation for reaming the inferior defect later. The sizer is carefully removed afterward.

The appropriately sized cartilage scoring tool is positioned over the superior pin and rotated manually through 1 full revolution to create a clean, shallow cut on the articular cartilage. The cut should extend beyond any existing cartilage defect. Only minimal pressure is needed, and bone penetration is not required at this stage.

The central femoral reamer with the hard-stop component is positioned over the superior pin and advanced until the hard stop indicates the proper depth. Continuous irrigation is used to prevent thermal necrosis. The pin is left in place after reaming.

The superior pin is overreamed using the secondary femoral oblong reamer until it sits 0.5 mm below the level of the surrounding cartilage. Depth is confirmed when the laser-marked line on the reamer aligns with the superior cartilage mark. In this position, the superior surface of the reamer closely corresponds to the thickness of the final implant.

The femoral oblong pin sizer is placed over the superior pin. The sizer is then aligned in the superoinferior axis with the inferior hole previously marked on the cartilage. The inferior pin is then inserted through the sizer into the previous socket until the first laser-marked line is flush with the top of the handle, ensuring the pin has reached the appropriate depth.

The inferior defect is now prepared. Similar steps are followed—including cartilage scoring, primary reaming with power, and secondary reaming over the inferior pin. We ensured that the hard stop is in place on the reamer before powering. During secondary reaming, the laser-marked line should align with the inferior cartilage mark before continuing hand reaming until the femoral secondary oblong reamer is recessed 0.5 to 1 mm below the cartilage surface. The superior and inferior reamed surfaces should be level, with no step off between them.

The appropriately sized femoral reamer guide is then inserted into the reamed implant defect. Any remaining cartilage visible through the guide is then scored with a scalpel. The central femoral reamer is positioned through the guide's round port and advanced using power until it reaches the built-in depth stop.

The fit and depth are then verified using the corresponding oblong femoral trial before the final implantation. The trial is then gently inserted and malleted into the reamed cavity so that its top is recessed 0.5 to 1 mm below the articular surface, accounting for physiologic compression of healthy cartilage. This recessed positioning helps prevent premature wear on the opposing tibial cartilage. The trial is removed once appropriate recessed positioning is confirmed.

The distal end of the peg drill is then inserted into the pin-created hole and advanced until its shoulders contact the bone. The same steps are then repeated for the second socket, and the area is irrigated to clear bone debris. The sockets are then filled with bone cement in preparation for hardware implantation.

Proper alignment of the oblong OvertureTi femoral implant's (Overture Orthopaedics) pegs with the drilled holes is confirmed before gently malleting the implant with the impactor until fully seated, making sure the edges are recessed 0.5 to 1 mm below the adjacent cartilage.

The site is irrigated. The arthrotomy and skin are then closed in standard layered fashion before applying sterile dressings and compressive bandages.

Results

Optimal results depend on precise implant preparation and placement. The pin sizer must sit flush with the native cartilage to avoid asymmetric reaming. Continuous irrigation helps prevent thermal injury during bone preparation. The trial and final implant should be recessed approximately 0.5 to 1 mm below the cartilage surface to reduce contact wear. For oblong lesions, careful alignment along the anteroposterior axis ensures both reamed surfaces match without a step-off.

At 2 weeks postoperatively, radiographs demonstrated well-positioned implants with preserved alignment and joint space. No apparent peri-implant radiolucency was seen.

While mid- to long-term outcomes of the Overture prosthesis have not yet been reported, data from other comparable focalplasty implants are available. The HemiCAP (Arthrosurface) metallic inlay prosthesis demonstrated significant clinical improvement over a 4-to-10-year follow-up of 64 knee implants, and patients who avoided revision showed significant improvements in pain and function, with no device failures beyond 5 years. ⁶ Another similar study reported improved patient-reported outcome scores at a mean 7.3-year follow-up, with a 10-year implant survival of 96.2% and few conversions to unilateral knee or total knee arthroplasty. ⁷

Discussion

The Overture system is currently indicated for focal osteochondral defects of the medial and lateral femoral condyles. ¹ Its design and implant geometry are optimized for the curvature and loading characteristics of these compartments. The Overture prosthesis represents a potential treatment option for active patients with focal cartilage lesions. Compared with arthroplasty and biologic resurfacing, it offers several advantages, including lower cost, off-the-shelf implant availability, preservation of native cartilage, meniscus, and ligaments, and bone preservation in the event that conversion to total or partial knee arthroplasty becomes necessary.^3,8 Nevertheless, evidence on long-term clinical outcomes remains limited. The indications are restricted to focal lesions confined to a single compartment, and the prosthesis is not appropriate for cases involving the entire femoral condyle or the posterior tibial plateau. To better define its role, larger, high-quality randomized controlled studies are required.

Regarding rehabilitation, immediate postoperative weightbearing is typically permitted. However, the weightbearing protocol must be tailored to the specific meniscal procedure performed. In this case, given that a medial meniscal root repair was performed, weightbearing restrictions were required.

In cases where the Overture implant is used without concomitant meniscal repair, the standard rehabilitation differs substantially from the present case. For isolated focalplasty, immediate weightbearing as tolerated is typically permitted, and a brace is not routinely required. Early restoration of the full range of motion is encouraged beginning on postoperative day 1, with no restrictions on flexion. Patients may return to low-impact activities by 4 to 6 weeks and progress to higher-impact activities between 8 and 12 weeks, depending on symptoms.