Intraoperative Patellofemoral Kinematic Acquisition: The Design, Testing, and Validation of a Setup for Clinical Studies.

: Abnormalities in patellar tracking, often overlooked in surgical planning, have been identified as a contributing factor to total knee arthroplasty (TKA) complications, including anterior knee pain, patellar subluxation, and dislocation. This study aims to evaluate the repeatability of a novel intraoperative setup for assessing patellofemoral kinematics and its interaction with prosthesis design and positioning during surgery. This setup may support personalized alignment techniques in TKA, potentially improving surgical outcomes.

Minimally invasive anatomic reconstruction of the anterolateral ligament with ipsilateral gracilis tendon: a kinematic in-vitro study.

Purpose: The anterolateral ligament (ALL) has been defined as a key stabilizer of internal tibial rotation at 35° or more of knee flexion, with a minimal primary or secondary stabilizing role in the AP direction. This study aimed to demonstrate that anatomical reconstruction of the ALL confers rotational stability equal to that of the uninjured knee.

Hypothesis: anteroposterior (AP) and rotatory laxity will significantly vary after ALL tenotomy and ALL reconstruction with the author's previously described technique.

The sagittal geometry of the trochlear groove could be described as a circle: an intraoperative assessment with navigation.

Purpose: The aim of this study was to describe the sagittal geometry of the trochlear groove in patients who underwent primary TKA, based on intraoperative data acquired with a navigation system.

Methods: Intraoperative navigation data were collected from 110 patients. All operations were guided by a non-image-based navigation system (BLU-IGS, Orthokey Italia Srl).

Does patellofemoral geometry in TKA affect patellar position in mid-flexion?

Purpose: This study aimed to compare the position of the patella at 90° of flexion before and after implantation of two TKA models with identical tibiofemoral geometry but different trochlear and patellar designs. The hypothesis was that the design with the deeper 'anatomic' trochlea could produce more natural patellar positions.

Methods: Intra-operative navigation data were collected from 22 consecutive cases that received two TKA designs (9 HLS Noetos(®) and 13 HLS KneeTec(®)).

The adductor tubercle: an important landmark to determine the joint line level in revision total knee arthroplasty.

Purpose: The restoration of the physiological femoro-tibial joint line (JL) is important to obtain a good outcome in revision total knee arthroplasty (RTKA). However, its assessment is challenging. The ratio of the distance between the adductor tubercle (AT) JL (ATJL) and the trans-epicondylar femoral width (FW) was proposed as a reliable method.

Good survivorship of all-polyethylene tibial component UKA at long-term follow-up.

Purposes: To determine the long-term survival rate of an all-polyethylene tibial unicompartmental knee arthroplasty (UKA) in a large series of consecutive patients and to investigate the possible factors that could influence the outcome.

Methods: A retrospective evaluation of 273 patients at 6-13 years of follow-up was performed. Clinical evaluation was based on KSS and WOMAC scores.

Three different cruciate-sacrificing TKA designs: minor intraoperative kinematic differences and negligible clinical differences.

Purpose: The goal of this study was to compare three types of mobile-bearing posterior cruciate ligament (PCL)-sacrificing TKA. The hypothesis was that the three designs provide differences in flexion stability and femoral rollback and improved clinical score at 2-year follow-up.

Methods: Three groups of patients, divided according to implant design, were analysed retrospectively.

In vivo kinematic evaluation of anatomic double-bundle anterior cruciate ligament reconstruction.

Background: There is controversy regarding the functional role of the posterolateral (PL) bundle of the anterior cruciate ligament (ACL).

Purpose: To evaluate the in vivo function of the PL and anteromedial (AM) bundles of the ACL during anatomic double-bundle (DB) ACL reconstruction for acute, isolated ACL tears utilizing a computer navigation system to track intraoperative knee kinematics.

Study Design: Controlled laboratory study.

Comparison of stability and kinematics of the natural knee versus a PS TKA with a 'third condyle'.

Purpose: The goal of this study was to compare the kinematics of knees before and after total knee arthroplasty (TKA) that relies on an inter-condylar 'third condyle'. The hypothesis was that the 'third condyle' provides sufficient flexion stability and induces a close to normal femoral rollback, thus granting natural joint kinematics.

Methods: Intra-operative navigation data were collected from 29 consecutive cases that received a cemented TKA (HLS Noetos, Tornier SA, France) designed with an inter-condylar 'third condyle' that engages within the tibial insert beyond 35° flexion.

Deep-dished highly congruent tibial insert in CR-TKA does not prevent patellar tendon angle increase and patellar anterior translation.

Purpose: Starting from the hypothesis that a deep-dished highly congruent tibial insert in cruciate-retaining total knee arthroplasty would prevent the increase in patellar tendon angle and anterior patellar translation by reducing the paradoxical anterior femoral translation, the main purpose of the present study was to investigate the effect of this prosthesis design, and secondary to assess the clinical outcomes at 6-month follow-up.

Methods: Twenty patients treated with cruciate-retaining total knee arthroplasty with navigation technique were enrolled and prospectively followed up at 6 months. The median value of age was 71 years (57-83).

Minimum thickness of all-poly tibial component unicompartmental knee arthroplasty in patients younger than 60 years does not increase revision rate for aseptic loosening.

Purpose: Management of unicompartmental knee osteoarthritis in middle-aged patients is a challenging problem. Despite its functional advantages, UKA still raises questions concerning implant survivorship and an increased revision risk for aseptic loosening mainly due to polyethylene wear. The main purpose of the present study was to investigate whether using the minimum thickness of an all-poly tibial UKA in patients under 60 years of age increases the revision rate for aseptic loosening.

Are the tubular grafts in the femoral tunnel in an anatomical or isometric position in the reconstruction of medial patellofemoral ligament?

Purpose: The purpose of this study was to evaluate the biomechanical results from the in vitro reconstruction of medial patellofemoral ligament (MPFL) using a navigation-assisted technique on a cadaveric model and its effects on patellar stability and kinematics. The authors investigated the hypothesis that patellar kinematics after reconstruction with a tubular graft are not optimal when compared with the original fan-shaped MPFL.

Methods: In six fresh-frozen cadaveric knees, lateral loads (25 N) were applied on the patella at 0°, 30°, 60° and 90° of knee flexion in three different MPFL states: intact, cut and reconstructed.

The influence of medial patellofemoral ligament on patellofemoral joint kinematics and patellar stability.

Purpose: Retinacular restraints have a critical role in patellar tracking, limiting the movement of the patella in the trochlear groove. The medial patellofemoral ligament (MPFL) is probably the main stabilizer against lateral displacement; few studies are focused on MPFL role on patellofemoral kinematics and patellar stability. The main goal of this in vitro study was to analyse the influence of the MPFL on the kinematics of the patellofemoral joint and patellar stability.

The adductor tubercle: a reliable landmark for analysing the level of the femorotibial joint line.

Purpose: The ratio of femoral width and distance from medial epicondyle to joint line helps estimate the femoral joint line position from femoral width. The approximately radial position of the medial epicondyle on femoral condyle spheres is probably responsible for this relationship, The adductor tubercle approximately lies diametrically opposite to the joint line on condylar sphere. Then, a linear correlation could also exist between the femoral width and distance of adductor tubercle to joint line and is the purpose of the current study.

An original clinical methodology for non-invasive assessment of pivot-shift test.

Even if pivot-shift (PS) test has been clinically used to specifically detect anterior cruciate ligament (ACL) injury, the main problem in using this combined test has been yet associated with the difficulty of clearly quantifying its outcome. The goal of this study was to describe an original non-invasive methodology used to quantify PS test, highlighting its possible clinical reliability. The method was validated on 66 consecutive unilateral ACL-injured patients.

Single-bundle patellar tendon versus non-anatomical double-bundle hamstrings ACL reconstruction: a prospective randomized study at 8-year minimum follow-up.

Purpose: The purpose of this study was to compare subjective, objective and radiographic outcome of the lateralized single-bundle bone-patellar tendon-bone autograft with a non-anatomical double-bundle hamstring tendons autograft anterior cruciate ligament (ACL) reconstruction technique at long-term follow-up.

Methods: Seventy-nine non-consecutive randomized patients (42 men; 37 women) with unilateral ACL insufficiency were prospectively evaluated, before and after ACL reconstruction by means of the above-mentioned techniques, with a minimum follow-up of 8 years (range 8-10 years; mean 8.6 years).

Computer-assisted anterior cruciate ligament reconstruction: an evidence-based approach of the first 15 years.

In the last 15 years, computer-assisted surgery (CAS) has been used for many purposes during anterior cruciate ligament (ACL) reconstruction, such as tunnel positioning, joint laxity evaluation, and biomechanical studies. This article is an evidence-based literature review of the contribution of such technology to ACL surgery. A search of the PubMed and Medline databases was performed.

Minimally invasive unicompartmental knee replacement: retrospective clinical and radiographic evaluation of 83 patients.

We performed a retrospective clinical and radiographic evaluation of 83 nonconsecutive patients operated in our institute between February 1996 and March 2003 with a mean follow-up of 60 months to assess the efficiency of unicompartmental knee replacement (UKR) performed with a minimally invasive technique. The aim of this study was to correlate the clinical outcome with the pre- and post-operative alignment and with implant positioning on coronal and sagittal plane. Eighty-three nonconsecutive patients (60 males, 23 females) underwent cemented UKR (De Puy Preservation Uni with all-poly tibial component), for both medial OA (80 patients) and AVN of the medial femoral condyle (3 patients).

Pivot-shift test: analysis and quantification of knee laxity parameters using a navigation system.

Lachman, drawer, and pivot-shift (PS) tests are important in the assessment of ACL reconstruction. The goal of this work was to analyze the reliability of the PS test using a navigation system, identifying a set of new quantitative parameters and evaluating their clinical relevance. Eighteen patients that underwent anatomic double-bundle ACL reconstruction were included.

Clinical relevance of static and dynamic tests after anatomical double-bundle ACL reconstruction.

A computer navigation system was used to collect kinematic data of 18 subjects undergoing ACL reconstruction. Surgical procedure was an anatomical four-tunnel hamstring double-bundle reconstruction. Static laxity and dynamic laxity were analyzed before and after graft passage and fixation.

Reliability of a navigation system for intra-operative evaluation of antero-posterior knee joint laxity.

Background: The purpose of this study was to investigate about the reliability of measuring antero-posterior laxity within-subjects for in-vivo studies using a navigation system.

Methods: The analysis was performed by enroling 60 patients undergoing anterior cruciate ligament ACL reconstruction, and assessing AP laxity during the Lachman and drawer tests.

Results: For the navigation system standard deviation for intra-trial measures was 0.

Intraoperative evaluation of total knee replacement: kinematic assessment with a navigation system.

Interest in the kinematics of reconstructed knees has increased since it was shown that the alteration of knee motion could lead to abnormal wear and damage to soft tissues. We performed intraoperative kinematic measurements using a navigation system to study knee kinematics before and after posterior substituting rotating platform total knee arthroplasty (TKA). We verified intraoperatively (1) if varus/valgus (VV) laxity and anterior/posterior (AP) laxity were restored after TKA; (2) if TKA induced abnormal femoral rollback; and (3) how tibial axial rotation was influenced by TKA throughout the range of flexion.

Does a lateral plasty control coupled translation during antero-posterior stress in single-bundle ACL reconstruction? An in vivo study.

The objective of this study was to quantify, in vivo, the reduction of knee laxity obtained by an extra-articular procedure, added to hamstring single-bundle (SB) anterior cruciate ligament (ACL) reconstruction in controlling coupled tibial translation during the Lachman and drawer tests. Twenty-eight patients were evaluated with a computer-assisted kinematic evaluation protocol; patients with associated ligament tears or meniscal damages were not included in the study. All patients underwent an hamstring ACL with an additional extra-articular procedure.

Knee stability before and after total and unicondylar knee replacement: in vivo kinematic evaluation utilizing navigation.

Surgical navigation systems are currently used to guide the surgeon in the correct alignment of the implant. The aim of this study was to expand the use of navigation systems by proposing a surgical protocol for intraoperative kinematics evaluations during knee arthroplasty. The protocol was evaluated on 20 patients, half undergoing unicondylar knee arthroplasty (UKA) and half undergoing posterior-substituting, rotating-platform total knee arthroplasty (TKA).

A novel computer-assisted surgical technique for revision total knee arthroplasty.

Revision total knee arthroplasty (RTKA) is a skill-demanding intervention presenting several technical challenges to the surgeon due to bone deficiencies and lack of anatomical references. Computer-assisted navigation systems can potentially solve these problems. An innovative computer-assisted surgical technique for RTKA is presented.