Long-term survival and complication rate of cementless prosthetic stems in primary total hip arthroplasty categorized by types according to Mont classification: a regional registry-based study on 53,626 implants.

INTRODUCTION: The purpose of this retrospective registry-based study is to assess survival and causes of failure of cementless stem implants used in total hip arthroplasty (THAs), to ascertain if there are differences when these are categorized according to the six types described by Mont. METHODS: Data collected from the regional registry regarding all primary THAs performed from 2000 to 2019 were analyzed. Femoral prosthetic stems were divided into the six types of Mont classification. For each stem type, number of implants, survival and causes of failure were evaluated and compared. RESULTS: The most frequently implanted stem type was the 3c type (53.4%). Type 1 had the lowest stem failure rate (1.6%), and type 6 showed the highest (3.9%). Periprosthetic fracture was the most frequent complication in type 6, accounting for 34.5% of failures. Aseptic loosening was the main complication in type 2 stems, accounting for 36.4% of failures. Pairwise comparisons showed significant higher survival of type 1 compared to type 3c (p = 0.000026) and type 6 (p = 0.000076), and between type 3a compared to type 3c (p = 0.03) and type 6 (p = 0.026). CONCLUSION: Significant variations in implant survival rates were found among the six Mont-types of cementless stems. These findings emphasize the paramount importance of stem design and fixation area in determining long-term survival, providing a guidance for orthopedic surgeons in the selection of the most appropriate stem for primary THA, contributing to our understanding of cementless stem performance, presenting invaluable insights to further improve patient outcomes in THA surgery.

The role of posterior condylar offset ratio on clinical and functional outcome of posterior stabilized total knee arthroplasty: a retrospective cohort study.

BACKGROUND: Postoperative Range of Motion (ROM) is an important measurement of the success of a Total Knee Arthroplasty (TKA). Much enthusiasm has been recently directed toward the posterior femoral condylar offset (PFCO), with some authors reporting increasing postoperative knee flexion when increasing PFCO. The aim of this study is to retrospectively determine the effect of the PFCO on the clinical and functional outcome of a cohort of patients who underwent a Posterior Stabilized (PS) TKA. METHODS: Clinical and radiological data of all patients who underwent TKA with PS implant for primary osteoarthritis were retrospectively reviewed. Knee Society Score (KSS), knee ROM, PFCO ratio (PFCOR), and tibial slope (TS) were measured pre and postoperatively. RESULTS: One hundred and twenty-one patients (141 knees) met the inclusion criteria. The mean knee flexion increased from 98 ± 20.2° (range 30-130) to 123 ± 12.1° (range 70-140) and the mean KSS increased from 74.0 ± 3.3 (range 27-130) to 203.9 ± 8.1 (range 26-249). Postoperative PFCOR and TS were 0.492 ± 0.005 (range 0.40-0.57) and 2.36 ± 0.56° (range - 10.9-12.15°), respectively. Neither maximal flexion angle nor KSS showed a significant correlation with postoperative PFCOR (Pearsons'r = - 0.057, p = 0.5 for flexion angle and Pearsons'r = - 0.073, p = 0.5 for KSS) or with postoperative TS (Pearsons'r = 0.042, p = 0.62 for flexion angle and Pearsons'r = 0.002, p = 0.98 for KSS). CONCLUSION: Posterior femoral condylar offset remains an important parameter and, especially when using anterior femoral referencing TKA, care must be taken to prevent excessive resection of the posterior femoral condyles.

Indications and timing in isolated medial femoral hemiepiphysiodesis for idiopathic genu valgum: A systematic review.

INTRODUCTION: Temporary isolated medial femoral hemiepiphysiodesis (TIMFH) represents a safe and effective technique widely used to treat idiopathic genu valgum. Recent studies mainly concentrated on comparing outcomes of different implants, while less attention has been reserved to the proper indications and timing for surgery. The aim of this systematic review was to provide evidence-based guidelines about indications for device implant and removal and postoperative management. METHODS: A comprehensive literature search was performed across three databases to select articles concerning TIMFH in the treatment of idiopathic genu valgum. Studies involving other etiologies or concomitant surgical procedures were excluded. Quality assessment of the included studies was conducted through the Newcastle-Ottawa Scale. RESULTS: Ten studies involving 237 patients for a total of 446 knees were included in the analysis. Mean age at surgery was 11,4 years. Patients were considered for surgery using various clinical and radiological parameters. Intermalleolar distance (IMD) and mechanical lateral distal femoral angle (mLDFA) were the most common evaluated. Mean treatment time was 12 months. Rebound of the deformity occurred in 6,7% of cases. CONCLUSION: Results of this review showed good consensus among authors. Patients undergoing TIMFH for IGV should be minimum 8 years old, with an IMD greater than 8 cm and a mLDFA lower than 87°. Postoperative management should comprise of quarterly clinic evaluations, and follow-up should last until skeletal maturity. The application of more uniform parameters in clinical practice may improve the establishment of the optimal timing for implant removal.

All-Polyethylene Tibial Component Does Not Affect Survivorship of Medial Unicompartmental Knee Arthroplasty at Mid-Term Follow-Up.

The present study's primary aim was to determine the survivorship of a large cohort of patients implanted with a single design all-polyethylene tibial component medial unicompartmental knee arthroplasty (UKA). Its secondary purpose was to investigate the reasons underlying implant failure, with specific attention to component positioning and limb alignment. Between 2007 and 2013, 166 patients underwent medial UKA with a single design all-polyethylene tibial component at two centers. Preoperatively and postoperatively, patients were administered clinical outcome scores and radiographic information were collected. Postoperative complications and causes of revision were recorded. A total of 140 patients (80 in Center A and 60 in Center B) who underwent all-polyethylene tibial component medial UKA (82 cases in Center A and 60 in Center B) were taken into account. Kaplan-Meier cumulative survivorship of implants was 96.5% (confidence interval [CI]: 91.7-98.6%) at an average follow-up of 61.1 months. Tibial aseptic loosening was accounted for failure in one case, while no correlation was found between implant positioning and failure. Two revisions were performed in Center A and three in Center B. Slight correction of the preoperative varus deformity was performed at both centers. All-polyethylene tibial component UKA provided satisfactory clinical and functional outcome, with excellent survival rate in the early and mid-term follow-up. Continued patient follow-up is needed to determine long-term survivorship of the examined UKA model.

The Impact of Bone Deformity on Osteoarthritic Varus Knee Correctability.

BACKGROUND: Bone deformities in the varus osteoarthritic knee may influence soft-tissue balancing and therefore knee correctability. The hypothesis of the present study was that the grade of coronal plane knee deformity may influence directly knee correctability along the entire range of motion from 0° to 90°. Tibial and femoral epiphyseal bone deformities were also analyzed to determine which kind had the greater impact on knee correctability. METHODS: A coronal plane deformity radiographic assessment and an intraoperative correctability assessment using computer-assisted surgery were performed on 118 varus osteoarthritic knees undergoing total knee arthroplasty. Knees were divided into groups taking into account the kind of bone deformity (tibial, femoral, and combined). RESULTS: A significant inverse correlation was found between coronal plane deformity and knee correctability at every 10 degrees of flexion. Correlation was strong at 0° and progressively got weaker at further flexion angles. According to literature, knees with a varus deformity >10° were rarely correctable in full extension, but often correctable in flexion, whereas knees with varus deformity >15° showed to be almost never correctable. Combined deformity group had a significantly lower rate of correctability along the entire range of motion. CONCLUSION: The severity of varus knee malalignment always influenced knee correctability with the knee in full extension, in further flexion (20°-60°), correctability was mildly affected. Isolated tibial epiphyseal deformity and combined epiphyseal deformity have the greatest impact on knee correctability.

Clinical outcome is not affected by total knee arthroplasty alignment.

PURPOSE: This study aims to analyse the influence on total knee arthroplasty (TKA) clinical outcomes of biomechanical intra-operative computer-assisted surgery-measured parameters, together with radiographic and demographical data. METHODS: Between 2007 and 2009, 227 computer-assisted surgery (CAS) primary TKAs were performed in 219 consecutive patients. Information about gender, age and body mass index (BMI) was collected for each patient. Before knee replacement, all patients underwent a complete radiographic examination and passive flexion-extension range of motion was recorded. All TKAs were implanted using an image-free knee navigation system. Patients included in the study were evaluated at 3, 6 and 12 months of follow-up and then yearly. At each follow-up, subjects were asked to answer the validated Italian version of the Knee Injury and Osteoarthritis Outcome Score. RESULTS: One hundred and eighty patients (187 knees) had data available for analysis. Complications were reported in 13 patients (7.0 %). Intra-operative CAS-measured parameters, together with age, BMI, gender, pre- and post-operative radiographic alignment, did not influence TKA clinical results at a mean 2 years of follow-up. On the other hand, higher post-operative flexion arc of movement was suggestive of better clinical outcomes. CONCLUSION: TKA clinical outcome is influenced by post-operative knee flexion, other than neutral mechanical limb alignment. Therefore, it is recommended to prefer TKA designs that allow high flexion and to encourage early physical rehabilitation. LEVEL OF EVIDENCE: IV.

In vivo kinematics of medial unicompartmental osteoarthritic knees during activities of daily living.

Few studies exist describing unicompartmental osteoarthritic knee kinematics. Moreover, the role of the anterior cruciate ligament (ACL) in the determination of knee kinematics has not been fully described. The objective of the current study was to analyze the in vivo kinematics of knees with medial osteoarthritis (OA) and intact ACL during closed and open chained motion. Eight patients scheduled for UKA diagnosed with primary medial OA underwent knee CT-scans and video-fluoroscopy. Fluoroscopic analysis included stair climbing, chair rising and leg extension. Three-dimensional bone positions were obtained from each image by iterative procedures using a CAD-model-based shape-matching technique. Patterns of axial rotation and anterior-posterior (AP) motion of the medial and lateral femoral condyle were obtained with specific software. The femur reported an overall external rotation relative to the tibia from extension to flexion in all tasks. Average AP translation of the medial femoral condyle were smaller in open-chained tasks than in weight-bearing conditions. Average AP motion of the lateral femoral condyle reported an overall posterior translation with knee flexion. The absent natural "screw-home" mechanism and the lack of medial condyle posterior translation was explained by bone-cartilage defects and meniscal degeneration. Relevant findings were the kinematic pattern differences between weight-bearing and open chained activities, suggesting that in biphasic muscle contraction and unloaded conditions, the function of the cruciate ligaments was not physiological. The kinematics of knees with medial OA and intact ACL differed from healthy knees.

Design and kinematics in total knee arthroplasty.

PURPOSE: Posterior stabilised (PS) total knee arthroplasty (TKA) design development that focused on restoring normal knee kinematics was followed by the introduction of reason-guided motion designs. Although all PS fixed-bearing knee designs were thought to have similar kinematics, reports show they have differing incidences and magnitudes of posterior femoral rollback and axial rotation. In this retrospective comparative study between two guided-motion total knee systems, we hypothesised that kinematic pattern has an influence on clinical and functional outcomes. METHODS: This study represents the continuation of a previously reported clinical and kinematics analysis. We retrospectively reviewed 347 patients treated with two different TKA designs: Scorpio NRG (Stryker Orthopedics) and Journey Bi-Cruciate Stabilised (BCS) knee system (Smith & Nephew). Two hundred and eighty-one patients were assessed clinically. Patients were divided into groups according to implanted TKA. Clinical evaluation with the Knee Injury and Osteoarthritis Outcome Score (KOOS) questionnaire was performed. Fifteen Scorpio NRG and 16 Journey BCS patients underwent video fluoroscopy during stair climbing, chair rising/sitting and step up/down at six months of follow-up. RESULTS: At an average 29 months of clinical follow-up, patients with Journey BCS TKAs reported better clinical results. Stiffness was more frequently reported in the Journey group (5.2 % vs 1.2 %), whereas anterior knee pain was observed in the Scorpio NRG group (1.9 %) only. Both prosthetic models reported different posterior translation of the medial and lateral contact points (CP) in all analysed motor tasks during knee flexion (BCS 10-18 mm; NRG Scorpio 2-3 mm). Both designs produced progressive external rotation of the femoral component relative to the tibia during flexion. CONCLUSIONS: Journey BCS showed statistically significant better KOOS results. The higher posterior femoral rollback observed in the kinematic assessment of this design, associated with a better patellofemoral design, may be the reason for better clinical outcome. The reported cases of stiffness and anterolateral joint pain could be attributed to excessive medial and lateral tibiofemoral posterior translation. The NRG group demonstrated good axial rotation, but this was not coupled with physiological kinematic patterns. Patellofemoral pain can be explained by a less friendly femoral-groove design. TKA clinical-functional outcome and complications were highly influenced by the bearing geometry and kinematic pattern of prosthetic designs.

Can TKA design affect the clinical outcome? Comparison between two guided-motion systems.

PURPOSE: In a retrospective comparative analysis in patients undergoing primary guided-motion total knee arthroplasty (TKA), the authors have evaluated whether different TKA implant design would influence the clinical and functional outcomes. METHODS: Between 2007 and 2009, 227 computer-assisted primary TKAs were performed in 219 consecutive patients. Patients received one of the two different fixed-bearing guided-motion TKA designs assisted by navigation surgery: the Scorpio Non-Restrictive Geometry (NRG) knee system and the Journey Bi-Cruciate Stabilized (BCS) knee systems. RESULTS: Data were available for 180 patients (187 knees). No significant differences were observed between the two groups with respect to preoperative demographic characteristics, range of motion (ROM) and radiographic knee alignment. At a mean follow-up of 29 months, the Journey BCS group had higher mean Knee Injury and Osteoarthritis Outcome Score (KOOS) in all subscales and a greater ROM than the Scorpio NRG group. This difference was statistically significant for the KOOS subscales of pain (p = 0.007) and knee-related quality of life (p = 0.045), as well as for postoperative ROM (p = 0.018). Considering the overall complications, 1 patient of Scorpio NRG group (0.5%) and 5 in Journey BCS (2.7%) had stiffness. Anterior knee pain was reported in 4 cases of Scorpio NRG group (2.1%). In the Journey BCS group were observed 2 cases (1.1%) of frontal plane instability and 1 case (0.5%) of synovitis pain. CONCLUSIONS: The bearing geometry and kinematic pattern of different guided-motion prosthetic designs can affect the clinical-functional outcome and complications type in primary TKA. LEVEL OF EVIDENCE: Clinical study, Level III.

Navigation-assisted total knee arthroplasty in knees with osteoarthritis due to extra-articular deformity.

PURPOSE: Extra-articular post-traumatic deformity may make difficult the implantation of total knee arthroplasty (TKA). Staged surgical procedures, including femoral or tibial osteotomy, can be required to restore proper alignment. These procedures may be inappropriate because of high rate of complications. Intra-articular resection is an alternative procedure, but it is limited by the potential compromise of collateral knee ligaments. Conventional instrumentation cannot be used in patients with previous trauma and residual bone deformity. We want to assess whether computer-assisted surgery may be a good alternative to traditional techniques. METHODS: Twenty consecutive TKAs were performed in 20 patients (12 men and 8 women) with knee arthritis due to extra-articular deformity. The mean age was 52 years. According to Moreland method, the mean (± standard deviation) of the pre-operative hip-knee-ankle angle was 10.4° ± 8.3° in varus. In all cases, an image-free knee navigation system was used because of the severe deformity or the presence of retained hardware that prevented the use of the intramedullary rod. The average follow-up was 3.1 years. RESULTS: One month after surgery, the mean hip-knee-ankle angle was 0.8° ± 1.2° in varus. At follow-up, the Knee Society Score increased from an average of 48 pre-operatively to 91 (P < 0.05) post-operatively, with over 90% of excellent and good results. Mean range of motion improved from a 7°-74° mean range pre-operatively to 0°-94° post-operatively. CONCLUSIONS: The general value of navigation systems in achieving accurate bone cuts and restoring the mechanical axis has been established in the literature for standard TKA but not yet for extra-articular deformity. Our findings at mid-term follow-up on a large cohort of these patients showed that these systems used for intra-articular resection are a very effective alternative to previous techniques. LEVEL OF EVIDENCE: Prospective study, Level IV.

Alignment deviation between bone resection and final implant positioning in computer-navigated total knee arthroplasty.

BACKGROUND: Computer-navigated total knee arthroplasty is aimed at improving accuracy in the positioning of prosthetic components and realigning the lower limb. The optimal position and orientation of the bone resection planes are targeted by the navigation system, but, after these are obtained, additional manual surgical actions, which may considerably affect final component alignment, are necessary for implantation. The aim of this study was to measure the alignment deviation caused by standard impaction of the tibial and femoral components following bone resections with use of navigation control. METHODS: Ninety-one primary total knee arthroplasties were performed with an image-free knee navigation system. The alignment of the tibial and femoral bone resections was measured in three planes during surgery by the instrumented probe of the system. The alignment measure was repeated after final tibial and femoral component implantation with cement. The alignment deviations between the two measures were considered the positioning error associated with the final manual implantation of the components. RESULTS: The alignment deviations between the bone resections and the subsequent implant placement were >1 degrees in the frontal plane of the femur and in the frontal and sagittal planes of the tibia in 20%, 11%, and 33% of the patients, respectively. The deviations were >2 degrees in 4%, 3%, and 9% of the patients, respectively. Deviations as large as 3 degrees were found at the tibia in the sagittal plane (the posterior slope). CONCLUSIONS: Positioning of the femoral and tibial components in total knee arthroplasty, which mainly involves cementation and impaction of the final components, can introduce a considerable error in alignment, regardless of how accurately the resection planes are made. After computer-navigated total knee arthroplasty, it would be useful therefore to check the alignment of the prosthetic component carefully before the cement hardens.

The minimally invasive osteotomy "S.E.R.I." (simple, effective, rapid, inexpensive) for correction of bunionette deformity.

BACKGROUND: A bunionette is a deformity of the fifth metatarsal bone with a varus deviation of the toe which can require surgical correction. Although numerous bony or soft tissue surgical procedures have been described, the ideal treatment has not yet been identified. The aim of this study was to retrospectively evaluate the results of a series of 50 consecutive feet affected by symptomatic bunionette deformity treated by S.E.R.I. (simple, effective, rapid, inexpensive) osteotomy. MATERIALS AND METHODS: Between February 1998 and March 2004, 50 feet with symptomatic type II-III bunionette deformity in 32 patients (18 bilateral) underwent S.E.R.I osteotomy. The average age of the patients at the time of operation was 33 +/- 13 years. The average followup was 4.8 (range, 2 to 8) years. RESULTS: The average modified lesser toe AOFAS score increased from 62.8 +/- 15.2 points preoperatively to 94 +/- 6.8 points at last followup (p < 0.0005). The average fifth metatarsophalangeal (MTP) angle decreased from 16.8 +/- 5.1 degrees preoperatively to 7.9 +/- 3.1 degrees at final followup (p < 0.0005). The 4-5 intermetatarsal angle (I.M.A) averaged 12 +/- 1.7 degrees preoperatively, while postoperatively was 6.7 +/- 1.7 degrees (p < 0.0005). Complications included a skin inflammatory reaction around the Kirschner wire and 2 symptomatic plantar callosities under the fourth metatarsal heads. CONCLUSIONS: The minimally invasive osteotomy is an effective and reliable technique for the treatment of painful bunionette, and it achieved more than 90% excellent and good results with reduced surgical time and complications.

Fixation of winged scapula in facioscapulohumeral muscular dystrophy.

OBJECTIVE: To verify if stabilizing the scapulothoracic joint without arthrodesis could lead to functional improvement of shoulder range of motion and clinical improvement of winged scapula, we incorporated four additional patients into our previous analysis to determine if the results obtained were long lasting, and to compare this fixation with the other techniques described in the literature, balancing the benefits with the complications. DESIGN: A retrospective study. PARTICIPANTS: Thirteen patients with bilateral winged scapula affected by facioscapulohumeral muscular dystrophy. Nine of these patients had been analyzed in our previous study. METHODS: Patients were operated on by bilateral fixing of the scapula to the rib cage using metal wires without arthrodesis (scapulopexy). RESULTS: All patients experienced improvement in active range of motion of the shoulder and all of them had clinical improvement with complete resolution of the winged scapula. In all twenty-six surgical interventions of scapulopexy, a stable and long-lasting fixation of the scapula to the rib cage was achieved. The complications strictly associated to the surgical technique encountered were one pneumothorax, which was resolved spontaneously, and one wire breakage without trauma. Average follow-up was 10 years (range, 3 to 18 years). CONCLUSION: The scapulopexy used in this extended series of patients consisted of repositioning the scapula and fixing it to four ribs by using metal wires without performing arthrodesis. This technique has a low rate of complications, is reproducible, safe and effective, resulting in clinical and functional improvement.