Total knee arthroplasty with simultaneous triplanar osteotomy of the distal femur using patient-specific instrumentation

Abstract

Purpose

Performing a one-stage periarticular osteotomy in conjunction with total knee arthroplasty (TKA) constitutes a technically complex procedure. In such demanding cases, a personalized approach utilizing patient-specific instrumentation (PSI) may serve as an advantageous option to achieve optimal precision in bone cuts, thereby enhancing both clinical and radiological postoperative outcomes.

Methods

We present a case report of a 22-year-old man with multiple epiphyseal dysplasia (MED) resulting in knee osteoarthritis with complex femoral deformity and restricted (passive at 30–120° and active at 80–120°) range of movement (ROM). Simultaneous TKA and triplanar osteotomy with the use of PSI stabilized with the prosthesis stem was performed.

Results

The treatment resulted in correct limb and implant positioning. The functional improvement and bone union were confirmed 1 year after TKA. The patient did not report any pain in the operated joints and achieved passive 0–120° and active 10–120° ROM of the operated right knee.

Conclusion

Although the latest reports do not demonstrate improved clinical outcomes for PSI in periarticular osteotomies and TKAs separately, we highlight the benefits of PSI in complex deformities, particularly in patients requiring a combination of these two methods.

Introduction

With the development of advanced technologies, such as surgical navigation, robotic arms, custom-made implants and patient-specific instrumentation (PSI), they are increasingly utilized in orthopedic surgery [1]. These methods may potentially improve the accuracy and reproducibility of total joint arthroplasty and osteotomy compared to those performed with conventional instrumentation [2, 3]. In computer-assisted total knee arthroplasty (TKA) and those performed with PSI, patient satisfaction and outcomes can be improved due to more precise bone cuts and the application of new alignment strategies and personalized implant positioning (kinematic and functional) [2, 4, 5]; however, many recent studies revealed no significant differences between robotic-assisted TKA and conventional TKA in terms of functional outcome scores, aseptic loosening, overall survivorship and complications [6–9]. On the other hand, several studies indicated that computer-assisted TKAs and those performed with PSI are beneficial for patients with complex knee anatomy, potentially leading to improved outcomes [10, 11]. Similarly, concerning osteotomy, PSI procedures do not show improved radiological and clinical outcomes. Still, they can aid in the execution of the preoperative plan in more complex cases, which facilitates performing multiple procedures simultaneously, yielding high accuracy and a low complication rate [12].

One-stage osteotomy combined with total knee arthroplasty is a demanding and challenging procedure and can be a valuable method of treatment in patients with advanced osteoarthritis and complex extra-articular deformity [13, 14]. Despite a few reports describing one-stage or two-stage protocols of TKA and osteotomy, a personalized strategy utilizing the PSI cutting block and reductor for the femur was not previously described [15, 16].

Case presentation

A 22-year-old man (67 kg, 162 cm, BMI = 25.5 kg/m²) diagnosed with multiple epiphyseal dysplasia (MED) was admitted to the orthopedic department due to moderate pain and massive contractures of the knees and hips caused by advanced osteoarthritis. Due to the significant range of motion (ROM) limitations, he used a wheelchair. At the age of 17 years, the patient underwent incorrectly performed bilateral rotational-extension osteotomy of the distal femurs in another orthopedic center. After the osteotomies, complete bone union with malposition of bone fragments was observed (Fig. 1a–c). At the first consultation, the patient presented with a minimal ROM with flexion contractures of the knees on both sides (30° passive and 70° active). The ROM of both knees was passive at 30–120° and active at 80–120° (Supplementary video 1). Inappropriate patellar tracking with lateralization and Lovett 5 muscle strength were additionally observed. Moreover, contractures and a limited range of the hips, spine and ankle joints were found.

Fig. 1.

Radiographs (a) anteroposterior (AP) and lateral of the (b) left and (c) right knees that showed bone union after osteotomy and AP (d) lateral of the (e) left and (f) right knees after removal of screws and plates

To perform appropriate radiological diagnostics, the patient was initially admitted to the hospital for screw and plate removal. After the hardware removal, plain radiographs (Fig. 1d–f) and computed tomography (CT) were performed. In the first stage, surgical intervention was planned for the right knee, followed by the right hip in a subsequent procedure. The CT scans of the lower limbs (rotating profile) revealed posterior luxation of the lateral tibial condyle, iatrogenic 65° of internal torsion of the right femur (angle measured between femoral neck axis and posterior condylar line, Fig. 2a, b). A 3D virtual model of the femur from the CT scans was generated and a 21° mechanical lateral distal femoral angle (mLDFA) and a 22° rearward bending of the distal femur in sagittal projection were due to a very complex deformity. After the digital planning, the patient was qualified for total knee arthroplasty with simultaneous triplanar osteotomy. To achieve precise correction of internal rotation, varus deformity, and posterior bending of the femur, the osteotomy was preoperatively planned on the virtual bone model (Fig. 3a, b). Figure 3c–e presents a bone geometry after planned reduction. The PSI cutting block for the osteotomy was designed and its positioning was planned virtually with cooperation with the engineer (BioCloner Health, Warsaw, Poland) and manufactured with the selective laser sintering (SLS) technique (Fig. 4a–d). After the surgeon (senior author) accepted the final project, the company performed trials of the distal femur, cutting block, reductor, and final PSI tools (suitable for sterilization, Fig. 5).

Fig. 2.

CT scans of (a) axial view of femoral neck and (b) posterior femoral condyles with calculated femoral torsion. 3D model generated based on CT scans (c) total view of the femur with calculated mLDFA, (d) torsion of the femur, and (e) posterior bending after the osteotomy

Fig. 3.

3D Model of planned osteotomy of the distal femur in (a) AP and (b) lateral views before the reduction (osteotomy wedge is marked red), and (c) AP, (d) lateral, and (e) AP total bone views after the osteotomy reduction

Fig. 4.

3D Virtual design of PSI cutting block in (a) antero-lateral, (b) postero-medial, (c) antero-medial, and (d) postero-lateral views

Fig. 5.

3D trial models of the distal femur and (a) osteotomy cutting block, and (b) osteotomy reductor. (c) A set of final cutting blocks and reductor implants that can be sterilized

A surgical procedure was performed via a lateral approach with the isolation of the Hoffa pad flap (Fig. 6a–c). After the exposure of the knee joint and lateral aspect of the distal femur, the cutting block was matched and stabilized by 4× 1.4 mm K-wires (implanted without conflict to the intramedullary canal as planned before) (Fig. 6d). Osteotomy of the distal femur was performed, and after removal of the cutting block and bone wedge, the osteotomy reduction was secured with the K‑wires to stabilize the bone fragment reposition (Fig. 6e, f). In the next step, the intramedullary canal was widened, and the bone cuts were performed according to the surgical technique for the semi-constrained condylar knee implant Triathlon TS (Stryker, Mahwah, NJ, USA) (Fig. 6g–i). Finally, the Triathlon universal tibial baseplate No. 3 and revision of the femoral implant with uncemented stem 10 mm diameter and 10 cm length, and 9 mm Triathlon TS insert were implanted (Fig. 6j). Due to very stable osteotomy fixation on the femoral stem (axial and rotational), no other fixation was used. Due to the risk of femoral shaft fracture associated with the very narrow intramedullary canal, a longitudinal bone cut was made prior to final prosthesis implantation. After the femoral prosthesis was implanted, a cable was placed prophylactically to reinforce the bone. Proper patellar tracking, full extension, and 130° of flexion were achieved intraoperatively.

Fig. 6.

Subsequent steps of the surgical procedure. (a) Preoperative maximum extension of the right knee. (b) Landmarks of the surgical approach. Knee joint exposure (c) and PSI cutting block placement (d). Osteotomy wedge before removal (e) and bone reposition with stabilization on the PSI reductor (f). Femoral and tibial cuts according to the Triathlon TS (Stryker) surgical technique (g–i). Patellar traction after the prosthesis implantation (j)

Postoperative complications were not observed. Radiological examination revealed properly positioned implants. Full weight bearing during standing with a walking frame was allowed. On the fifth day after surgery, full extension and 80° of flexion were achieved by the patient (Fig. 7a). At 6 months after the TKA, the patient underwent a THA on the right side, and 2 months later (8 months after the TKA), the patient was able to stand for the first time without any assistance, 3 months after THA on the right side, he decided to undergo a THA on the left side (9 months after the TKA). The progressive bone union was observed and 1 year after the TKA, the bone union of the osteotomy was confirmed. The patient did not report any pain in the operated joints and achieved passive 0–120° and active 10–120° ROM of the operated right knee. The patient underwent a TKA 15 months and 2 weeks after the right-sided TKA with simultaneous osteotomy performed with a PSI cutting block on the left side. Figure 7b–d presents X‑rays 17 months after right TKA and 6 weeks after left TKA.

Fig. 7.

Physical examination of the patient was performed on the 5th day after surgery (a). Full extension of the knee was achieved. Radiograms performed 17 months after surgery (b) AP and (c) lateral, progressive bone union was revealed. (d) Full length AP view performed 17 months after the surgery, after subsequently performing total hip arthroplasty (Trident/MDM/Accolade II; Stryker) and 6 weeks following TKA with simultaneous femoral osteotomy with the use of PSI on the left side

Discussion

Patients with severe osteoarthritis and those with complex deformities require accurate preoperative planning before the implementation of surgical procedures. Previously performed surgeries, such as osteotomy around the knees or posttraumatic deformities, may also increase the difficulty of TKA concerning implant positioning and soft tissue balancing. Achieving proper alignment can be challenging in patients with extra-articular deformities due to potential obstructions from a sclerotic or curved canal, which can hinder the use of an intramedullary guide [5].

In patients with extra-articular deformity with < 10° in the coronal plane, soft tissue release and asymmetrical intra-articular bone resection or personalized implant alignment may be a solution [17, 18]; however, in more demanding cases with more complex deformities, performing the osteotomy before or during the same procedure is needed [19]. Single or two-stage protocols of osteotomies on the femur or tibia site with TKA were described with good clinical and functional results [13, 16, 20, 21].

In the presented case, we decided to perform a single-stage TKA in a patient with severe iatrogenic extra-articular, triplanar deformities of the femur with OA secondary to MED. To achieve the precise correction of the deformity, a PSI osteotomy block was created and applied during the surgery. Due to good experience and satisfactory bone union success, we decided to perform a single-stage procedure with TKA and intramedullary stabilization of the osteotomy, only with the femoral implant stem, without the additional fixation material [22]. Intramedullary stabilization with the use of a prosthesis stem or nail may lead to obtaining sufficient bone union in the osteotomy site as well as in the case of a periprosthetic fracture [22, 23]; however, preoperative planning and the assessment of the possibility of using this technique are required in specific patients.

Despite the increasing use of PSI devices in TKA procedures, the latest reports do not show improved clinical outcomes in comparison to conventional instrumentation and procedures performed with surgical navigation, but slightly improved implant position and limb alignment [3, 9, 24]. Concerning application costs, PSI is associated with fewer operating room resources (requiring less instrumentation), but these savings do not compensate for the costs of design and manufacturing [25, 26]. Nevertheless, we highlight the advantages of PSI in complex, multiaxial, intra-articular and extra-articular deformities or atypical patient anatomy, and for those cases where the proper use of conventional instrumentation may be challenging, e.g., in patients with additional materials (nails, screws, stems) that may conflict with intramedullary rods. Our results are in line with Vaziri et al., who performed the TKA with PSI osteotomy on the tibial site [27]. We agree that in these situations, less soft tissue damage can be achieved, and the precision of establishing bone cuts, limb alignment, and implant positioning is significantly better. Additionally, accurate preoperative planning and digital templating in these specific groups of patients is mandatory to avoid intraoperative complications and to achieve good radiological, clinical and functional outcomes [28].

Conclusion

The application of PSI for complex osteotomy around the knee with or without simultaneous TKA can improve the accuracy of the bone cuts, decrease the complication rate, and shorten the time of surgery. Accurate preoperative planning and close collaboration between the surgeon and engineer are crucial to achieving favorable execution of the surgical procedure and postoperative outcomes; however, there is a need to conduct prospective studies to confirm the usefulness of PSI dedicated to osteotomy in this specific group of patients who require simultaneous TKA.

Abbreviations

CT

Computed tomography

MED

Multiple epiphyseal dysplasia

mLDFA

Mechanical lateral distal femoral angle

PSI

Patient-specific instrumentation

ROM

Range of motion

SLS

Selective laser sintering

TKA

Total knee arthroplasty

Availability of data and materials

The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.

Declarations

Conflict of interest

W. Szerksznis, E. Tramś, R. Kamiński and D. Grzelecki declare that they have no competing interests.

Consent for publication.

Written informed consent was obtained from the patient for publication of this case report and any accompanying images.

For this article no studies with human participants or animals were performed by any of the authors. All studies mentioned were in accordance with the ethical standards indicated in each case.