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Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_9 | Pages 18 - 18
1 May 2016
Bruni D Marcacci M Bignozzi S Zaffagnini S Iacono F
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Introduction

Proper alignment (tibial alignment, femoral alignment, and overall anatomic alignment) of the prosthesis during total knee replacement is critical in maximizing implant survival[7] and to reduce polyethylene wear[1]. Poor overall anatomic alignment of a total knee replacement was associated with a 6.9 times greater risk of failure due to tibial collapse, that varus tibial alignment is associated with a 3.2 times greater risk[2] and valgus femoral alignment is associated with a 5.1 times greater risk of failure[7]. To reduce this variability intramedullary (IM) instruments have been widely used, with increased risk of the fat emboli rate to the lungs and brain during TKA[6] and possible increase of blood loss[4, 5]. Or, alternatively, navigation has been used to achieve proper alignment and to reduce morbidity[3]. Recently, for distal femoral resection, inertial sensors have been coupled to extramedullary (EM) instruments to improve TKA surgery in terms of femoral implant alignment, with respect to femoral mechanical axis, and reduced morbidity by avoidance of IM canal violation. The purpose if this study is to compare blood loss and alignment of distal femoral cut in three cohorts of patients: 1 Operated with inertial based cutting guide; 2 Operated with navigation instruments; 3 operated with conventional IM instruments.

Material and methods

From September to November 2014 30 consecutive patients, eligible for TKA, were randomly divided into three cohorts with 10 patients each:x 1 “EM Perseus”, patient operated with EM inertial based instruments (Perseus, Orthokey Italia srl, Florence, Italy); 2 “EM Nav”, operated with standard navigated technique, where bone resections were planned and verified by mean of navigation system (BLUIGS, Orthokey Italia srl, Florence, Italy); 3 “IM Conv”, operated with standard IM instrumentation. All patients were operated by the same surgical technique, implanted TKA were mobile bearing PS models, Gemini (Waldemar Link, Hamburg, Germany) and Attune (Depuy, Warsaw, Indiana). Anteroposterior, lateral, and full-limb weightbearing views preoperatively and postoperatively at discharge were obtained, taking care of neutral limb rotational positioning in all patients enrolled in the study. Angles between femoral mechanical axis and implant orientation on frontal and lateral planes were measured with a CAD software (Rhinoceros 3, McNeel Europe, Rome, Italy) by two independent persons, average value was used for statistical analysis. Haemoglobin values were recorded at three time intervals: the day before surgery, at 24h follow-up and at patients discharge.


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_7 | Pages 56 - 56
1 May 2016
Bruni D Bragonzoni L Bontempi M Akkawi I Raspugli G Iacono F Marcacci M
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The main purpose of the present study was to determine long-term implant fixation of 15 unicompartmental knee arthroplasty (UKAs) with an all-poly tibial component using Roentgen stereophotogrammetric analysis (RSA) at a mean 10-year follow-up. The secondary purpose was to investigate whether the progressive loss of implant's fixation correlates with a reduction in Knee society score (KSS). Fifteen non-consecutive patients with primary knee osteoarthritis received a UKA with an all-poly tibial component were assessed using KSS scores pre-operatively and post-operatively and RSA on day 2 after surgery, then at 3, 6, and 12 months and yearly thereafter. The mean last follow-up was 10 years. An increase in maximum total point motion (MTPM) values from 6 months to 1 year post-operatively was found respect to post-operative reference. Implants’ displacement values were always 2 mm during the first 6 months, and then, two different trends were noticed in revised and non-revised implants. MTPM increase between 1 and 2 years of follow-up in non-revised UKAs was always 0.2 mm, whereas it was [0.2 mm in revised UKAs. A linear and negative correlation with statistical significance was found between MTPM and both clinical and functional KSS scores (p 0.001). Also in a long-term follow-up evaluation, RSA is an effective tool to predict functional results after an all-poly UKA providing also a relevant predictive value at 1 year follow-up, and this can be very useful for both patients and surgeons.


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_7 | Pages 57 - 57
1 May 2016
Bruni D Iacono F Bignozzi S Marcacci M
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The main purpose of the present study is to prospectively investigate whether preoperative functional flexion axis in patients with osteoarthritisand varus-alignment changes after total knee arthroplasty and whether a correlation exists both between preoperative functional flexion axis and native limb deformity. A navigated total knee arthroplasty was performed in 108 patients using a specific software to acquire passive joint kinematics before and after implant positioning. The knee was cycled through three passive range of motions, from 0 to 120. Functional flexion axis was computed using the mean helical axis algorithm. The angle between the functional flexion axis and the surgical transepicondylar axis was determined on frontal (aF) and axial (aA) plane. The pre- and postoperative hip-kneeankle angle, related to femur mechanical axis, was determined. Postoperative functional flexion axis was different from preoperative only on frontal plane, while no differences were found on axial plane. No correlation was found between preoperative aA and native limb deformity, while a poor correlation was found in frontal plane, between aF and preoperative hip-knee-ankle angle. Total knee arthroplasty affects functional flexion axis only on frontal plane while has no effect on axial plane. Preoperative functional flexion axis is in a more varus position respect to the transepicondylar axis both in pre- and postoperative conditions. Moreover, the position of the functional axis on frontal plane in preoperative conditions is dependent on native limb alignment, while on axial plane is not dependent on the amount of preoperative varus deformity.


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_1 | Pages 56 - 56
1 Jan 2016
Bruni D Marko T Gagliardi M Bignozzi S Zaffagnini S Akkawi I Colle F Marcacci M
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Introduction

The purpose of this study was to examine whether three types of mobile-bearing PCL sacrificing TKA could restore the native knee translation and rotation. The primary hypothesis was that there are differences in knee kinematics and laxity between three different cruciate-substituting TKA designs: 1 with post-cam mechanism, 2 post-cam mechanism based on an inter-condylar ‘third condyle’ concept, 3 anterior stabilized with deep-dished highly congruent tibial insert; specifically, showing different femoral external rotation with flexion, different femoral translation with flexion and different laxity under stress test. The secondary hypothesis was that there is different clinical outcome between the three TKA designs at 2 years follow-up.

Methods

We recruited 3 cohorts consisting of 30 patients each divided according 3 different TKA designs. All patients were operated with navigated procedure. During surgery preoperative and postoperative kinematics were recorded, in terms of femoral antero-posterior translation and tibial rotation during knee flexion, as also preoperative and postoperative at 2 years follow-up clinical scores have been acquired.


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_1 | Pages 57 - 57
1 Jan 2016
Bruni D Gagliardi M Grassi A Raspugli G Akkawi I Marko T Marcacci M
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BACKGROUND

Some papers recently reported conflicting results on implant survivorship in all-poly tibial UKRs. Furthermore, the influence of BMI on this specific implant survivorship remains unclear, since existing reports are often based on small series of non-consecutive patients with different follow up durations, enabling to generate meaningful conclusions.

PURPOSE

To determine the 10-years survival rate of an all-poly tibial UKR in a large series of consecutive patients and to investigate whether a correlation exists between a higher BMI and an increased risk of revision for any reason.


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_1 | Pages 58 - 58
1 Jan 2016
Bruni D Bragonzoni L Gagliardi M Bontempi M Marko T Patella S Marcacci M
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Background

Roentgen Stereophotogrammetric Analysis (RSA) represents nowadays an excellent solution for high-accuracy fixation measurement of UKAs. To date, to the best of our knowledge, no previous study has investigated long-term micromotions of a UKA using RSA. For this reason, the main purpose of the present study is to determine long-term implant fixation of 15 UKAs with all-poly tibial component using RSA at a mean 10-years follow-up. The secondary purpose was to investigate whether the progressive loss of implant's fixation correlates with a reduction of KSS scores.

Methods

Fifteen non-consecutive patients with primary knee osteoarthritis received a UKA with an all-poly tibial component between January 1995 and April 2003 in the Authors' institution. Pre and post-operative KSS scores were recorded. RSA evaluation was performed on day 2 after surgery, than at 3, 6, and 12 months and yearly thereafter. The patients were evaluated with a mean follow-up of 10 years.


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_1 | Pages 92 - 92
1 Jan 2016
Colle F Lopomo N Bruni D Gagliardi M Marko T Francesco Iacono Zaffagnini S Marcacci M
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Introduction

Providing proper rotational alignment of femoral component in total knee arthroplasty is mandatory to achieve correct kinematics, good ligament balance and proper patellar tracking. Recently functional references, like the function flexion axis (FFA), have been introduced to achieve this goal. Several studies reported the benefits of using the FFA but highlighted that further analyses are required to better verify the FFA applicability to the general clinical practice. Starting from the hypothesis that the FFA can thoroughly describe knee kinematics but that the joint kinematics itself can be different from flexion to extension movements, the purpose of this study was to analyse which factors could affect the FFA estimation by separately focusing on flexion and extension movements.

Methods

Anatomical acquisitions and passive joint kinematics were acquired on 79 patients undergoing total knee arthroplasty using a commercial navigation system. Knee functional axis was estimated, from three flexion and extension movements separately acquired included in a range between 0° and 120°. For flexion and extension, in both pre- and post-implant conditions, internal-external (IE) rotations was analysed to track any changes in kinematic pattern, whereas differences in FFA estimation were identified by analysing the angle between the FFA itself and the transepicondylar axis (TEA) in axial and frontal plane.


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_1 | Pages 55 - 55
1 Jan 2016
Bruni D Gagliardi M Marko T Raspugli G Akkawi I Marcacci M
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PURPOSE

Lateral osteoarthritis of the valgus knee is a challenging problem, especially for young and active patients, where prosthetic replacement is not indicated. The purpose of the present study is to evaluate clinically and radiographically 91 patients with valgus knee treated with distal femoral varus osteotomy in mid and long term follow-up.

METHODS

A clinical retrospective evaluation based on IKDC, OXFORD and WOMAC scores of 91 patients at 4 to 10 years of follow-up was performed. Subjective evaluation was based on a VAS for pain self-assessment. Radiographic evaluation was performed by an independent observer of all 91 patients at 2 to 6 years of follow-up. A survival analysis was performed assuming revision for any reason as primary endpoint.


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_1 | Pages 94 - 94
1 Jan 2016
Colle F Lopomo N Bruni D Francesco Iacono Zaffagnini S Marcacci M
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Introduction

Several methods, based on both functional and anatomical references, have been studied to reach the goal of a proper knee kinematics in total knee arthroplasty (TKA). However, at present, there is still a large debate about which is the most precise and accurate method to achieve the correct rotational implant positioning. One of the main methods already used in TKA to describe the tibiofemoral flexion-extension movement, based on a kinematic technique, thus not influenced by the typical variability related to the identification of anatomical references, is called “functional flexion axis” (FFA) method. The purpose of this study was to determine the repeatability in estimating knee functional flexion axis, thus evaluating the robustness of the method for navigated total knee arthroplasty.

Methods

Passive kinematic and anatomical acquisitions were performed with a commercial navigation system on 87 patients undergoing TKA with primary osteoarthritis. Knee FFA was estimated, before and after implant positioning, from three flexion-extension movements between 0° and 120° (Figure 1). The angle between Functional Flexion Axis and an arbitrary clinical reference, the transepicondylar axis (TEA), was analysed in frontal and axial view (Figure 2). Repeatability Coefficient and Intraclass Correlation Coefficient (ICC) were estimated to analyse the reliability and the agreement in identifying the axis.


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_1 | Pages 93 - 93
1 Jan 2016
Colle F Lopomo N Bruni D Capozzi M Zaffagnini S Marcacci M
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Introduction

The use of a surgical navigation system has been demonstrated to allow to intraoperatively analyze knee kinematics during total knee arthroplasty (TKA), thus providing the surgeon with a quantitative and reproducible estimation of the knee functional behaviour. Recently severak authors used the computer assisted surgery (CAS) for kinematic evaluations during TKA, in particular to evaluate the achievement of a correct joint biomechanics after the prosthesis implantation. The major concern related to CAS is that the movements are usually passively performed, thence without a real active task performed by the subject. Starting from the hypothesis that the passive kinematics may properly describe the biomechanic behaviour of the knee, the main goal of this work was to intra-operatively compare the active kinematics of the limb, analysing a flexion movement actively performed by the patient, and the passive kinematics, manually performed by the surgeon.

Methods

The anatomical and kinematic acquisitions were performed on 31 patients TKA using a commercial navigation system (BLU-IGS, Orthokey, USA). All the surgeries were performed under local anesthesia, which specifically allowed to acquire the passive and active kinematics including three flexion movements. Both in pre- and post-implant conditions, internal-external (IE) rotations and anterior-posterior (AP) translations were estimated to track any changes in the kinematic pattern.


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_34 | Pages 245 - 245
1 Dec 2013
Bruni D Iacono F Raspugli G Akkawi I Marcacci M
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Purpose:

Management of unicompartmental knee osteoarthritis (OA) in middle-aged patients is a challenging problem. Recent studies have underlined the efficacy of UKA not just in elderly, but also in middle-aged patients. The primary purpose of the present study was to determine the short to mid-term survivorship of an all-poly tibial UKA in patients under 60 years of age. The secondary purpose was to prospectively evaluate the clinical outcome in this selected group of patients.

METHODS:

Thirty-three consecutive patients under 60 years of age at the time of surgery with isolated medial compartment OA underwent a unilateral medial UKA from 2002 to 2005 and were prospectively followed. A Kaplan-Meyer analysis was performed to determine the 8-years implant survivorship with revision for any reason as endpoint. KSS, WOMAC, Tegner-Lysholm, Tegner and VAS scores were prospectively evaluated at 3 to 6 years follow-up. Weight-bearing radiographs were collected pre-operatively and at 3 to 6 years follow-up to prospectively evaluate femorotibial angle (FTA), tibial plateau angle (TPA) and posterior tibial slope (PTS).


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_34 | Pages 247 - 247
1 Dec 2013
Bruni D Bragonzoni L Bontempi M Gagliardi M Akkawi I Marcacci M
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Introdution:

Over the last years research has focused on attempts to achieve better fixation in knee prosthesis by improving cementing techniques and prosthetic designs; thus prosthetic fixation is critical while loosening at the bone-cement interface is still an important matter for the orthopaedic surgeon.

Material and Method:

In the present study, we evaluated in vivo displacement of both total and unicompartimental knee prosthesis implanted on 73 patients by collecting data from RSA associated to the conventional X-rays and clinical follow-ups; we were able to reach only 18 patients (2 males and 16 females) for the actual follow up because of death or other diseases occurred on the other patients over the years (mean age at the time of surgery 68, range 27–83).


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_34 | Pages 19 - 19
1 Dec 2013
Bruni D Iacono F Colle F Bignozzi S Marcacci M
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BACKGROUND:

The optimal reference for rotational positioning of femoral component in total knee replacement (TKR) is debated. Navigation has been suggested for intra-op acquisition of patient's specific kinematics and functional flexion axis (FFA).

QUESTIONS/PURPOSES:

To prospectively investigate whether pre-operative FFA in patients with osteoarthritis (OA) and varus alignment changes after TKR and whether a correlation exists between post-op FFA and pre-op alignment.


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_34 | Pages 246 - 246
1 Dec 2013
Bruni D Bragonzoni L Gagliardi M Bontempi M Marcacci M
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The Rizzoli Orthopaedic Institute has been involved in RSA since 1998. During last 25 years, several investigations have been carried on to evaluate both implant fixation and poliethylene deformation in unicompartmental and total knee replacements. Nevertheless, RSA has also been used to investigate the relative micromotions and the kinematic modifications in cadaveric models of ankles with ligamentous injuries. RSA evaluation has demonstrated that in a particular TKR implant, with mobile half-bearings, the threshold for loosening was 1.3° for rotation about the longitudinal axis and 0.5 mm for medio-lateral translation. Moreover, RSA has revealed cold flow to be concentrated in the posterior region of the medial half-bearing. This has lead to further improvement in polyethilene and implant design. RSA has also demonstrated that in all-poly tibial UKR, poliwear does not impair tibial component fixation and that deformation of the all-poly tibial component is strictly correlated to implant loosening. Moreover, RSA has been used to investigate stress-inducible displacement of the tibial component in all-poly UKRs. It has been demonstrated that rotations around the transverse axis of the knee joint are the most common form of stress-inducible displacement, while stress-induced translations are negligible. Moreover, stress-inducible translational displacement has reached significantly higher values for those patients with unexplained painful UKR, despite no sign of loosening on conventional radiographic and standard supine RSA evaluations.

Further application of RSA has focused on the kinematic evaluation of poliethilene motion pattern modifications throughout a 3 years follow-up period after a mobile-bearing TKR. Patients have been investigated in weight-bearing conditions and results demonstrated that longitudinal rotations and medio-lateral translations tended to increase at last follow-up, while sagittal translations dod not show any significant modification over time.

At present, a new device has been installed at the Istituto Ortopedico Rizzoli. It was specifically designed and made for RSA, static and fluoroscopic. This device can work both in mono- and bi-planar configuration as required by the RSA protocols. Moreover it is able to acquire image stacks in order to study the in-vivo and real time kinematics of a joint. he theoretical biomechanical resolution of a static RSA followup tests is 0.2 mm for translation and 0.3° for rotation. In fluoroscopic configuration the theoretical resolution is 1 mm for translation and 1° for rotations, depending on the used frame rate and on the joint movement speed. A kinematic comparison of different prosthetic designs is currently ongoing, to evaluate different motion patterns under dynamic weight-bearing conditions and to compare them with passive kinematics acquired intra-operatively using a navigation system.


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_15 | Pages 26 - 26
1 Mar 2013
Bruni D Iacono F Presti ML Raspugli G Sharma B Marcacci M
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INTRODUCTION

The purpose of our work was to evaluate changes in clinical scores, passive knee kinematics and stability after mobile bearing TKA surgery.

MATERIAL AND METHODS

60 patients were treated with a mobile bearing prosthesis (Gemini, Waldemar Link, Hamburg, Germany). PCL was always resected. Inclusion criteria were BMI >30, age range 60–80 yrs. Preoperative KSS, KOOS and SF36 scores were recorded. Surgeries were performed with a navigation system (BLU-IGS, Orthokey Italia, Firenze, Italy) to verify bone cuts, ligament balancing and implant positioning. Kinematic tests were executed to determine: tibial rotation and femoral translation through flexion range. Stability tests were performed using varus-valgus stress in extension and at 30° of flexion and drawer test. Acquisition were perfomed with menisci and cruciate ligaments intact, and repeated after final implant fixation. Clinical scores were recorded at 6 months follow-up.


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_15 | Pages 140 - 140
1 Mar 2013
Bruni D Iacono F Lo Presti M Raspugli G Sharma B Marcacci M
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INTRODUCTION

The literature suggests a survivorship of unicompartmental knee arthroplasties (UKA) for spontaneous osteonecrosisof the knee range from 93% to 96.7% at 10 to 12 years. However, these data arise from series reporting 23 to 33 patients, jeopardizing meaningful conclusions.

OBJECTIVES

Our purpose is to examine a long term survivorship of UKA's in a larger group of patients with SPONK, along with their subjective, symptomatic and functional outcome; to determine the percentage of failures and the reasons for the same in an attempt to identify relevant indications, contraindications, and technical parameters in treating SPONK with a modern implant design.


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_15 | Pages 25 - 25
1 Mar 2013
Bruni D Iacono F Presti ML Sharma B Raspugli G Marcacci M
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INTRODUCTION

Conventional surgical exposures are usually inadequate for 2-stage revision knee replacement ofinfected implants. Reduced range of motion, extensor mechanism stiffness, peripatellar contracture and soft tissue scarring make patellar eversion difficult and forced eversion places the integrity of the extensor mechanism at risk. On the contrary, a wide exposure is fundamental to allow complete cement spacer removal, soft tissue balancing, management of bone loss and reimplantation without damaging periarticular soft tissues.

OBJECTIVES

To compare the long-term clinical, functional and radiographic results and the reinfection rate of the quadriceps snip approach and the tibial tubercle osteotomy in 2-stage revision knee replacement performed for septic loosening of the primary implant.