Total knee arthroplasty in extra articular deformities: A series of 36 knees

Staged Extra-Articular Deformity Correction in the Setting of Total Knee Arthroplasty

Background

Extra-articular lower-leg deformities mandate unique considerations when planning total knee arthroplasty (TKA). Poor limb alignment may increase perioperative complications and cause early implant failure. This study reports on the safety and efficacy of staged, extra-articular deformity correction about the knee in the setting of osteoarthritis and TKA.

Methods

A retrospective review was conducted from December 2007 to December 2019 identifying 30 deformities in 27 patients (average age: 52.7 years; range 31-74) who underwent staged surgical correction of extra-articular deformity in preparation for TKA. Patient demographics, surgical details, clinical and radiographic measurements, severity of knee arthritis, and complications were collected.

Results

There were 17 femur and 12 tibia deformities. There was an average improvement of 14.7° of deformity measured in the coronal plane and 12.7° of deformity in the sagittal plane in the femur and 13.5° in the coronal plane and 10.3° in the sagittal plane in the tibia. Leg length discrepancies improved by 26 mm on average (1-100 mm). After an average 3.1-year follow-up, 12 out of 27 patients proceeded with primary or revision TKA. There were no cases of blood transfusion, nerve palsy, or compartment syndrome, and all patients achieved bony union.

Conclusions

Staged, extra-articular deformity correction is a safe and effective approach to improve limb alignment in the setting of knee osteoarthritis and TKA.

Robotic-assisted total knee arthroplasty for extra-articular femur deformity correction

Femoral shaft fracture is one of the most common injuries encountered. However, improper management can lead to significant long-term complications, of which is malunion. Patients with femoral malunion are at increased risk of developing knee osteoarthritis, and if arthroplasty is indicated, these extra-articular deformities pose a challenge as corrective osteotomy and soft tissue release are also required. In such circumstances, robotic arm-assisted total knee arthroplasty (RATKA) might be an appropriate option. In this case, we present a 66-year-old woman who had previously suffered a femur shaft fracture, which was treated conservatively, and developed a varus malunion and severe knee osteoarthritis, and who was treated with RATKA.

Total knee arthroplasty for severe valgus deformity of the knee with extra-articular deformities of the femur and tibia using a 3-dimensional image matching software system

INTRODUCTION AND IMPORTANCE

Knee osteoarthritis with femoral and/or tibial extra-articular deformities makes total knee arthroplasty (TKA) technically difficult to perform, especially using intramedullary-based instrumentation systems. The Athena Knee 3-dimensional (3-D) image matching software is effective for TKA with an extra-articular deformity, especially in case of using a long-stem prosthesis or not available computer-assisted navigation systems.

CASE PRESENTATION

A 79-year-old woman presented with right knee pain secondary to a progressive valgus deformity and gait disturbance. She had experienced a supracondylar femoral fracture fifteen years ago, and a tibial shaft fracture ten years ago on the same side; both of fractures were treated surgically. She had a severe valgus knee deformity and extra-articular deformity of femur and tibia, and valgus stress test detected medial knee instability. The range of motion was 0° in extension and 75° in flexion. Severe medial knee laxity compelled us to use a constrained and long-stem prosthesis, resulting in the use of an intramedullary guided system. The 3-D software system helped us to determine the amount of bone to cut as well as the appropriate entry points for the intramedullary rods and mechanical axis restoration. At two years after surgery, knee range of motion improved to 90° in flexion, and walking ability had also advanced from the use of two crutches to that of a T cane.

CONCLUSION

The 3-D image matching software system for preoperative planning was useful for TKA with extra-articular deformity, especially in the case of a long-stem prosthesis without using a navigation system.

Surgical principles for complex primary total knee arthroplasty in the presence of extra-articular deformity

Background

Accurate restoration of alignment is vital to the success of a total knee arthroplasty (TKA) procedure. Deformities, whether these are intra-articular and/or extra-articular AND/OR whether these are uniplanar/multiplanar/complex, can impose varying technical challenges in surgical planning and execution. Literature on performing TKA in presence of limb deformity is limited, especially for extra-articular deformities.

Objectives

The objectives of this narrative review are twofold. Firstly, we analyse the existing English literature for studies focussed on TKA and deformity correction and summarise the important points about deformity pathomechanics, clinical and radiological assessment, pre-operative planning and surgical techniques. The second objective is to provide the readers with a simplistic and wholistic management algorithm to assist surgeons in meticulous planning to tackle the technical challenges imposed by lower limb deformities while performing a TKA.

Discussion

Approach to each patient must be holistic and customised on an individual basis according to patient characteristics, deformity characteristics and surgeon experience. The three main options available are: (1) Primary TKA (symmetric cuts/asymmetric cuts with/without computer navigation assistance) (2) Single stage corrective osteotomy and TKA and (3) Two-staged deformity correction and TKA. A multi-disciplinary team approach is required and a knee surgeon well-versed in revision arthroplasty and a limb reconstruction surgeon specialising in deformity correction, should be involved from the outset. The use of computer navigation technology, particularly for deformity correction and TKA, has increased over the last couple of decades and is recommended by the authors for these challenging cases.

Tibial reference point in total knee arthroplasty in patient with proximal tibia vara: A case report

Introduction

Center of the intercondylar eminence at the proximal tibia had been widely used as a reference point for tibial bone cut in the Total Knee Arthroplasty (TKA) procedure. However, in the presence of preexisting tibia vara, the center of intercondylar eminence as tibial bone cut reference point often leads to varus malalignment after TKA procedure.

Case report

75 years old male patient complained of worsening pain on the left knee. The patient has had a history of knee osteoarthritis for the past seven years. The radiograph on the right knee revealed osteoarthritis grade 3 and left knee osteoarthritis grade 4, both with tibia vara. We planned to perform total knee arthroplasty surgery on his left knee with a preoperative planning tibial reference point of 10 mm lateral to the center. Six months after the knee replacement, there was minimal pain on activity, and full ROM was achieved on his left knee. On the radiographic X-ray evaluation, the alignment between the tibial implant surface and mechanical axis is 0.43 degrees valgus.

Clinical discussion

In a varus knee malignment, the mechanical axis passes through one-third of the medial side of the knee, which makes the medial side of the implant wear off faster, resulting in the collapse of the medial tibia, thus decreasing implant survival and increasing the need for revision for TKA.

Conclusion

In patients with preexisting tibia vara, tibial bone cut reference point planning before TKA procedure is important to provide longevity of implant survival and better quality of life.

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Normal coronal alignment to the mechanical axis is important for long-term implant survival

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The correct alignment by bone cuts will restore the neutral mechanical axis of the femur and tibia in the coronal plane

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In tibia vara, the center of intercondylar eminence as a tibial bone reference often leads to varus malalignment after TKA

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The tibial bone cut reference should be calculated according to the degree of the tibia vara deformity

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In patient with tibia vara the tibial cut reference point is lateral to the center of intercondylar eminence

How Does Robotic-Arm Assisted Technology Influence Total Knee Arthroplasty Implant Placement for Surgeons in Fellowship Training?

Implant malalignment during total knee arthroplasty (TKA) may lead to suboptimal postoperative outcomes. Accuracy studies are typically performed with experienced surgeons; however, it is important to study less experienced surgeons when considering teaching hospitals where younger surgeons operate. Therefore, this study assessed whether robotic-arm assisted TKA (RATKA) allowed for more accurate and precise implant position to plan when compared with manual techniques when the surgery is performed by in-training orthopaedic surgical fellows. Two surgeons, currently in their fellowship training and having minimal RATKA experience, performed a total of six manual TKA (MTKA) and six RATKAs on paired cadaver knees. Computed tomography scans were obtained for each knee pre- and postoperatively. These scans were analyzed using a custom autosegmentation and autoregistration process to compare postoperative implant position with the preoperative planned position. Mean system errors and standard deviations were compared between RATKA and MTKA for the femoral component for sagittal, coronal, and axial planes and for the tibial component in the sagittal and coronal planes. A 2-Variance testing was performed using an α = 0.05. Although not statistically significant, RATKA was found to have greater accuracy and precision to plan than MTKA for: femoral axial plane (1.1° ± 1.1° vs. 1.6° ± 1.3°), coronal plane (0.9° ± 0.7° vs. 2.2° ± 1.0°), femoral sagittal plane (1.5° ± 1.3° vs. 3.1° ± 2.1°), tibial coronal plane (0.9° ± 0.5° vs. 1.9° ± 1.3°), and tibial sagittal plane (1.7° ± 2.6° vs. 4.7° ± 4.1°). There were no statistical differences between surgical groups or between the two surgeons performing the cases. With limited RATKA experience, fellows showed increased accuracy and precision to plan for femoral and tibial implant positions. Furthermore, these results were comparable to what has been reported for an experienced surgeon performing RATKA.

Handheld computer-navigated constrained total knee arthroplasty for complex extra-articular deformities

INTRODUCTION

The present study aimed to assess the postoperative alignment and clinical outcomes of patients with complex extra-articular deformities (EADs) undergoing computer-assisted surgery (CAS) for constrained total knee arthroplasty (TKA) with modular stem extensions.

MATERIALS AND METHODS

From May 2015 to July 2018, ten patients with EADs scheduled for constrained TKA were enrolled retrospectively. The preoperative average deviation from neutral (= 180°) mechanical axis was 15.3° (range of coronal alignment: 150.9° varus-202.9° valgus). Alignment was assessed using an accelerometer-based handheld CAS system. On long-leg films, the positions of the components and possible stems were analysed and templated preoperatively. The average follow-up was 3.3 years (range: 2.0-4.6 years).

RESULTS

The postoperative mechanical axis was within ± 3.0° from neutral in nine patients. In all patients, the Knee Society score (KSS) and range of motion improved significantly. A constrained condylar and a rotating hinge prosthesis were used in five patients each. In eight patients, the 100-mm cementless stem that was preferred by the authors was found to be unusable for the femur or the tibia in the planning stage. For the femur, a cementless 100-mm stem was used in three, and a cemented 30-mm stem in five patients; a femoral stem was not usable in two patients. For the tibia, a cementless 100-mm stem was used in six, and a cemented 30-mm stem in two patients; a monoblock rotating hinge tibia was used in two patients.

CONCLUSIONS

Complex EADs were excellently managed during constrained TKA implantation using the handheld CAS system. Templating allowed the possible stem lengths to be identified and prevented anatomical conflict with the CAS-configured mechanical alignment. Limb alignment and function improved significantly after surgery. No intra- or postoperative complications occurred.

LEVEL OF EVIDENCE

Level IV, retrospective study.

Congenital Fibular Deficiency: Total Knee Arthroplasty with Extraarticular Deformity: A Case Report

CASE

A total knee arthroplasty (TKA) was performed on a 35-year-old man with congenital fibular deficiency and a 20° varus and 28° antecurvatum tibial deformity of the left lower limb.

CONCLUSION

One-stage TKA and correction of the extraarticular deformity by means of intraarticular bone resections and a standard soft tissue release were performed to restore the limb's mechanical axis. Patients with congenital fibular deficiency present a wide range of limb deformities because of bone deficiencies or treatment sequels, which might require a specific surgical technique and small-sized implants to obtain good results during a TKA.

Total knee arthroplasty with simultaneous tibial shaft osteotomy in patient with multiple hereditary osteochondromas and multiaxial limb deformity - a case report

BACKGROUND

Hereditary multiple osteochondromas (hereditary multiple exostoses, HME) is a rare genetic disease characterized by the development of benign osteocartilaginous tumors that may cause severe limb deformities and early onset osteoarthritis. Total knee arthroplasty (TKA) is the method of choice for the treatment of advanced gonarthrosis, however the surgical management with coexisting severe axial limb deformity remains unclear.

CASE PRESENTATION

65-year-old man with HME and extra-articular multi-axial limb deformity was admitted to the orthopedic department due to chronic knee pain and limited range of motion caused by secondary osteoarthritis. Regarding to the clinical and radiological examinations, after preoperative planning he was qualified to a one-stage TKA combined with tibial shaft osteotomy (TSO). In a one year follow-up full bone union was confirmed with no signs of implant loosening or prosthesis displacement. Patient was very satisfied, did not report any joint pain and has sufficient range of motion without knee instability.

CONCLUSION

The improvement of mechanical axis during TKA is a crucial factor for achieve operative success and long implant survival. Despite the higher risk of complication rate in comparison to two-stage treatment, one-stage TKA with simultaneous TSO should be a considerable method for patients with osteoarthritis and multiaxial limb deformities. This method can give a good clinical and functional outcomes, however should be performed subsequently to careful preoperative planning and proper patient qualification.

Total Knee Arthroplasty in Patients With Extra-Articular Deformity: Restoration of Mechanical Alignment Using Accelerometer-Based Navigation System

BACKGROUND

Total knee arthroplasty (TKA) in patients with post-traumatic extra-articular deformity (EAD) is difficult to manage using conventional instrumentation techniques. In this study, we evaluate whether accelerometer navigation system can be a valuable option to make accurate bone resections and restore the neutral mechanical axis in complex TKA patients with EAD.

METHODS

From May 2015 to June 2017, 18 consecutive TKA were performed in 18 patients with knee osteoarthritis with associated EAD. An accelerometer-based navigation system was used to guide tibial and femoral resection in the coronal and sagittal plane. Postoperative lower limb alignment in coronal plane and component position in coronal and sagittal plane was measured through full-leg weight-bearing X-ray. Clinical score were recorded using the Knee Society Score at the final follow-up.

RESULTS

The mean hip-knee-ankle angle was 0.9° ± 1.4° varus alignment. The coronal alignment of the femoral component was 89.2° ± 1.9°, and the coronal alignment of the tibial component was 89.4° ± 2.1°. The sagittal alignment of the femoral component was 93.2°± 1.9°, and the sagittal alignment of the tibial component was 84.4° ± 3.1°. At the final follow-up, the Knee Society Score was 89 points (range, 82-100), and the functional score was 86.7 points (range, 60-100). No intraoperative and postoperative surgical complications were reported using this technology.

CONCLUSION

Accelerometer-based navigation is accurate in achieving neutral mechanical alignment and optimal implant position after TKA in patients with EAD. This system should be considered a valuable option to the more complex technique of computer navigation or robotic surgery.

Planning a total knee arthroplasty through an application for mobile devices: case report

For decades, the main cause of failure in total knee arthroplasty (TKA) is still the malalignment of prosthetic components. The authors present a case of advanced knee arthrosis, treated by TKA. Preoperative planning was performed with a mobile application and the patient was submitted to primary TKA using an implant developed with inspiration from the theory of "modified GAP" with a rotated tibial tray. Neutral mechanical alignment of the lower limbs was obtained and the application proved to be viable regarding its proposed plan for this case.

Total knee arthroplasty for treatment of osteoarthritis associated with extra-articular deformity

OBJECTIVE

Our purpose was to review senior author results of TKA in patients with extra-articular angular deformities (correction of mechanical axis was performed without an additional procedure for osteotomy).

METHODS

Results of TKA in nine knees with osteoarthritis and associated extra-articular angular deformity of femur were reviewed retrospectively. This group was compare with a with a control group of 20 patients diagnosed with osteoarthritis that underwent TKA without extra-articular deformity. Angulation of deformity in patients was 19° in coronal plane (range 15°-25°) and 12° in sagittal plane (range 8°-5°). Knee Score (KS) and Functional Score (FS) were measured pre and post-surgery, likewise arc flexion was reported. Results in KS and FS were correlationed with extra-articular angulation.

RESULTS

Duration of follow-up averaged 55 months (range, 48-63 months). KS Average and FS increased from 50.5 and 38.4 points, preoperatively, to 96.5 and 84.4 points, respectively, at time of following-up. No statistically significant differences in any postoperative parameters were found between the postoperative group of extra-articular deformities and the control group were found. Positive correlation was obtained between deformity degrees and KS. Arc of motion averaged 86° preoperatively and 118° at time of following-up. No total knee arthroplasty was revised.

CONCLUSION

In our opinion, best management for extra-articular deformities associated to osteoarthritis is to carry out a knee replacement without corrective osteotomy on condition that planification allow to us avoid ligaments insertions, using an extensive soft-tissue balancing in conjunction with a minimally constrained TKA.

One-stage computer-assisted total knee arthroplasty and tibial osteotomy

Same-stage tibial osteotomy may deserve consideration in candidates to total knee arthroplasty (TKA) who have severe bone deformities, particularly at extra-articular sites. This strategy obviates the need for either a major and technically difficult ligament release procedure, which may compromise ligament balancing, or the use of a semi-constrained prosthesis. This technical note describes a one-stage, computer-assisted technique consisting in TKA, followed by corrective tibial osteotomy to obtain an overall mechanical axis close to 180° without extensive ligament balancing. This technique provided satisfactory outcomes in 8 patients followed-up for at least 3years, with no specific complications or ligament instability and with a hip-knee-ankle angle close to 180°. After planning, intra-operative computer assistance ensures accurate determination of both implant position and the degree of correction achieved by the osteotomy.

Single Stage Tibial Osteotomy and Long Stem Total Knee Arthroplasty to Correct Adverse Consequences of Unequal Tibial Lengthening with an Ilizarov Circular Fixator

Introduction:

Correction of limb alignment or length discrepancy by circular external fixation is an accepted technique which relies on the correct biomechanical application of the frame and precise corrections which are frequently delegated to the patient to perform. Errors can occur in the execution of the correction by the patient and may result in significant deformity that requires remedial intervention.

Case Report:

A 67 Caucasian female underwent multifocal limb reconstruction of the lower limb utilising a complex Ilizarov frame. Attendance at follow-up visits did not occur and the patient presented at 6 months with severe deformity due to incorrect execution of the correction protocol which resulted in a 45 degree varus deformity of the tibia. Subsequent correction via acute tibial osteotomy and stabilisation with a stemmed total knee replacement resulted in a good outcome.

Conclusion:

Patient compliance with post-operative management is paramount with distraction osteogenesis and should be ensured prior to embarking on lengthening or deformity correction.

Total knee arthroplasty in the valgus knee

Valgus knee deformity is a challenge in total knee arthroplasty (TKA) and it is observed in nearly 10% of patients undergoing TKA. The valgus deformity is sustained by anatomical variations divided into bone remodelling and soft tissue contraction/elongation. Bone tissue variations consist of lateral cartilage erosion, lateral condylar hypoplasia and metaphyseal femur and tibial plateau remodelling. Soft tissue variations are represented by tightening of lateral structures: lateral collateral ligament, posterolateral capsule, popliteus tendon, hamstring tendons, the lateral head of the gastrocnemius and iliotibial band. Complete pre-operative planning and clinical examination are mandatory to manage bone deformities and soft tissue contractions/elongations and to decide if a higher constrained prosthesis is necessary. Two different approaches have been described to perform TKA in a valgus knee: the anteromedial approach and the anterolateral one. In valgus knee deformity bone cuts can be performed differently in order to correct low-grade deformities and reduce great deformities. There is still debate in the literature on the sequence of lateral soft tissue release to achieve the best alignment without any instability. The aim of this article is to review the anatomical variations underlying a valgus knee, to assess the best pre-operative planning and to evaluate how to choose the grade of constraint of the implant. We will also review the main approaches and surgical techniques both for bone cuts and soft tissue management. Finally, we will report on our experience and technique.