Tibial periprosthetic fracture is an important complication of the Oxford Unicompartmental Knee Replacement (OUKR). Primary fixation of cementless OUKR tibial components relies on the interference-fit of the ‘keel’ and a slot in the proximal tibia. Clinically used double blade keel saws (DKS) create slots with two grooves, generating stress concentrations where fractures may initiate. This study aimed to investigate slot factors that may influence incidence of tibial periprosthetic fractures.

Slots were made in PCF20 polyurethane foam using the DKS plus/minus adjuvant rasping, single blade keel saw (SKS), and rasp-only. Round and square slots were machined with milling cutters. Compact tensile tests were conducted per ASTM E399 to determine tensile load to fracture (TLTF) and results were validated using bovine tibia. Cementless OUKR components were implanted into slots in custom polyurethane blocks and compressed to failure to determine anatomical load to fracture (ALTF). A custom MATLAB program calculated slot roundness from cross-sectional images.

Round slots had higher TLTF (29.5N, SD=2.7) than square (25.2N, SD=1.7, p<0.05) and DKS slots (23.3N, SD=2.7, p<0.0001). Fractures occurred at the round slot apices, square slot corners, and deepest DKS slot grooves. ALTF was not significantly different between square and round slots. Adjuvant rasping made DKS slots significantly rounder, resulting in significantly higher TLTF, but rasping did not increase ALTF. ALTF was significantly higher for SKS (850N, SD=133, p<0.01) and rasp-only (912N, SD=100, p<0.001) slots compared to standard DKS slots (703N, SD=81).

Round keel slots minimise stress concentrations and increase TLTF but do not increase ALTF. The SKS and rasp-only slots retain material at slot ends and have significantly higher ALTF. Future studies should assess saw blades that retain material and round slot ends to evaluate if their use may significantly reduce the incidence of tibial periprosthetic fracture.

Abstract

Abstract

Objectives

The aim of this study was to determine the polyethylene wear rate of Phase 3 Oxford Unicompartmental Knee Replacement bearings and to investigate the effects of resin type and manufacturing process.

Objectives

The primary stability of the cementless Oxford Unicompartmental Knee Replacement (OUKR) relies on interference fit (or press fit). Insufficient interference may cause implant loosening, whilst excessive interference could cause bone damage and fracture.

The aim of this study was to identify the optimal interference fit by measuring the force required to seat the tibial component of the cementless OUKR (push-in force) and the force required to remove the component (pull-out force).

High tibial osteotomy is an efficient treatment for medial compartment osteoarthritis of the knee; its used for middle aged patients with high activity levels and can delay the need for total arthroplasty.

The results of total knee arthroplasty after failed high tibial osteotomy are controversies; several authors reported inferior outcomes, but others have concluded that tibial osteotomy doesn't bias following total arthroplasty. The aim of this study was to evaluate the results of failed high tibial osteotomy subsequently converted to total knee arthroplasty and compare the results to group of patients underwere primary arthroplasty; the authors evaluate some of technical problems that a previous high tibial osteotomy can generate, like scar tissue, patellar tendon shortening and changes of proximal tibial anatomy.

High tibial osteotomy is an efficient treatment for medial compartment osteoarthritis of the knee; its used for middle aged patients with high activity levels and can delay the need for total arthroplasty.

The results of total knee arthroplasty after failed high tibial osteotomy are controversies; several authors reported inferior outcomes, but others have concluded that tibial osteotomy doesn’t bias following total arthroplasty. The aim of this study was to evaluate the results of failed high tibial osteotomy subsequently converted to total knee arthroplasty and compare the results to group of patients underwere primary arthroplasty; the authors evaluate some of technical problems that a previous high tibial osteotomy can generate, like scar tissue, patellar tendon shortening and changes of proximal tibial anatomy.

Methods: 50 total knee arthroplasty performed after a previous closed wedge osteotomy were matched with 50 patients operated with a primary knee prosthesis for osteoarthritis. The time from a proximal tibial osteotomy to a prosthesis operation was in mean eight years.

Results: the Knee Society clinical and radiographic score system and W.O.M.A.C. evaluation were used to evaluate knees before surgery and at each follow up (average 5 years).

At an average of five years follow up, the clinical results of total knee arthroplasty after high tibial osteotomy were similar to those of primary knee prosthesis.

Discussion: in our study revision of failed proximal tibial osteotomy appears to have more technical difficulties but with overall outcomes that remain comparable at results after primary total knee arthroplasty, so tibial osteotomy is considered a valid option in younger and very active patients with unicompartmental arthritis.

High tibial osteotomy is an efficient treatment for medial compartment osteoarthritis of the knee; its used for middle aged patients with high activity levels and can delay the need for total arthroplasty.

The results of total knee arthroplasty after failed high tibial osteotomy are controversies; several authors reported inferior outcomes, but others have concluded that tibial osteotomy doesn’t bias following total arthroplasty. The aim of this study was to evaluate the results of failed high tibial osteotomy subsequently converted to total knee arthroplasty and compare the results to group of patients underwere primary arthroplasty; the authors evaluate some of technical problems that a previous high tibial osteotomy can generate, like scar tissue, patellar tendon shortening and changes of proximal tibial anatomy.

Methods: 50 total knee arthroplasty performed after a previous closed wedge osteotomy were matched with 50 patients operated with a primary knee prosthesis for osteoarthritis. The time from a proximal tibial osteotomy to a prosthesis operation was in mean eight years.

Results: the Knee Society clinical and radiographic score system and W.O.M.A.C. evaluation were used to evaluate knees before surgery and at each follow up (average 5 years).

At an average of five years follow up, the clinical results of total knee arthroplasty after high tibial osteotomy were similar to those of primary knee prosthesis.

Discussion: in our study revision of failed proximal tibial osteotomy appears to have more technical difficulties but with overall outcomes that remain comparable at results after primary total knee arthroplasty, so tibial osteotomy is considered a valid option in younger and very active patients with unicompartmental arthritis.

Introduction: A prospective study was done to compare the early clinical, radiographic outcomes between the Scorpio CR and Scorpio Flex CR primary total knee replacement.

Methods: 130 Scorpio CR and 40 Scorpio Flex CR were implanted. Patients were prospectively evaluated with a mean follow-up of 3,9 years (2–8 years). Knee Society Score, W.O.M.A.C., range of motion and knee pain was compared. Patients age, level of activity, BMI, were criteria selection for implant of Scorpio Flex CR.

Results: There was more pain in Scorpio CR group, mean flexion was greater in Scorpio Flex CR (112 vs 108); Knee Society score and WOMAC was better in Scorpio Flex CR group.

Conclusion: The Scorpio Flex CR new design may be allow the significant increase in Knee Society score and the better ROM in Scorpio Flex CR group.

Obesity is strongly linked to osteoarthritis; can affect the outcome of total knee arthroplasty and can increase the load on the components with reduction of the implant’s survivorship.

The purpose of this study is to compare clinical and radiographic outcomes in obese (defined as BMI > 30) and non obese patients.

The Knee Society scoring system and WOMAC was used to evaluate the knees preoperately and at latest follow up.

With a follow up ranging from 1 to 5 years, Knee Society score and WOMAC for the patients who were obese were lower than non obese patients.

Non progressive radiolucent lines were located adjacent to the tibial component in the group of obese patients, but without clinical significance.

Introduction Shoulder replacement is a classical indication in 3 and 4 part humeral head fractures, but the results reported in literature are not so good like arthritis. This is for some aspects as healing of tuberosity, rotatory cuff repair and difficult in positioning of prosthesis for lack of landmarks. The aim of this study is to assess the overall outcome of 30 patients treated with shoulder prosthesis for proximal humeral fractures.

Methods Quality of life assessment, specific shoulder patients perspective and objective parameters were correlated with position of stem. Height and version of the stem, evaluated with CT scan as reported in Literature, were studied and correlated whether with the other side or with subjective and objective data.

Subjective data included SF-36, DASH, Simple shoulder test; active and passive ROM, muscles strength etc. represented objective data. A rigorous statistical analysis was performed.

Results No statistical significative correlation were detected between position and subjective outcome. Different data are found for objective data as ROM, that appears correlate with position of stem.

Conclusion No papers about these aspects of shoulder replacement exist in Literature.

The authors believe that better knowledge of correlation between outcome and technical aspects in shoulder replacement could be important to define surgical practice criteria.

Introduction MRI accuracy in detecting knee lesions is a discussed controversy. Not always different knee lesions, diagnosed by MRI are confirmed by arthroscopy. The aim of this study is to correlate the accuracy of history, physical examination and MRI in evaluating meniscal and ACL lesions.

Methods A prospective comparative study was performed to compare anamnestic and clinical data, MRI findings and arthroscopic findings to better understand the role of these methods and to assess if there are significative differences between various knee disorders. One hundred patients undergoing to arthroscopy for knee injuries were evaluated before surgery, registering anamnestic data, clinical examination and MRI findings. At the time of surgery every finding was registered and then compared with the previous acquired data.

Results The most accurate data for diagnosis appears from history and clinical examination. The study showed a statistically significative differences between the RMI and arthroscopic findings. Differences between radiologist were detected in MRI data.

Conclusion The results of such type of study, underlining the reliability and accuracy of patient’s history, clinical examination and MRI, comparing the different results among them and in various knee injuries. The accuracy of every test is the first step for an evidence based decision analysis process and represent a step forward an efficacious and economical pattern in diagnosis.

Shoulder replacement has increased exponentially over the past decades due to good results reported in literature and improvement of surgical technique and devices efficacy. Previous studies suggested the effectiveness of shoulder replacement in fractures, assessing objective parameters as range of motion and radiographic images and evaluating the of postoperative complications and subsequent revision; pain relief, physical function level and health related quality of life (QoL) improvement were often left out. A prospective study was conducted on 21 patients surgically treated with shoulder emiarthroplasty for proximal humeral fractures (18 women and 3 men, mean age at follow-up 70 years – range: 57–82). The purpose of the present study is to collect the patient-relevant outcomes in a homogeneous sample (for surgeon, surgery, implant, inclusion-exclusion criteria, neurological status) of patients who underwent shoulder replacement for proximal humeral fractures. Preoperatively patients were evaluated through x-rays (trauma series), Ct-scans were performed when necessary for surgical decision. Postoperatively, two independent examiners examined all patients clinically and radiographically. For patient-oriented standardized measure SF-36, DASH (Disability of Arm, Shoulder and Hand questionnaire), ASES (American Shoulder and Elbow Surgeon), OSQ (Oxford Shoulder Questionnaire) and SST (simple Shoulder test) were chosen. Outcomes of our series were statistically compared with literature data and widely analyzed. This kind of data are unavailable in literature and could represent the first step towards the definition of outcome for this kind of procedure.

High tibial osteotomy is an efficient treatment for medial compartment osteoarthritis of the knee; its used for middle aged patients with high activity levels and can delay the need for total arthroplasty.

The results of total knee arthroplasty after failed high tibial osteotomy are controversies; several authors reported inferior outcomes, but others have concluded that tibial osteotomy doesn’t bias following total arthroplasty. The aim of this study was to evaluate the results of failed high tibial osteotomy subsequently converted to total knee arthroplasty and compare the results to group of patients underwere primary arthroplasty; the authors evaluate some of technical problems that a previous high tibial osteotomy can generate, like scar tissue, patellar tendon shortening and changes of proximal tibial anatomy.

Methods: 50 total knee arthroplasty performed after a previous closed wedge osteotomy were matched with 50 patients operated with a primary knee prosthesis for osteoarthritis. The time from a proximal tibial osteotomy to a prosthesis operation was in mean eight years.

Results: the Knee Society clinical and radiographic score system and W.O.M.A.C. evaluation were used to evaluate knees before surgery and at each follow up (average 5 years).

At an average of five years follow up, the clinical results of total knee arthroplasty after high tibial osteotomy were similar to those of primary knee prosthesis.

Discussion: in our study revision of failed proximal tibial osteotomy appears to have more technical difficulties but with overall outcomes that remain comparable at results after primary total knee arthroplasty, so tibial osteotomy is considered a valid option in younger and very active patients with unicompartmental arthritis.