Correlation between cephalic screw positioning of Standard Gamma 3 Nail for intertrochanteric fractures and cut-out incidence

INTRODUCTION

Lateral fractures of proximal femur are the most frequent fractures in elderly people. Internal fixation using medullary nails is the gold standard of treatment (Gamma 3 nail is the most implanted device) due to reduced incidence of complications than other devices. We report our experience in treating this kind of fractures with Gamma 3 nail, between January 2015 and December 2021.

METHODS

We performed a retrospective cohort study of patients treated in our orthopaedic department; level of clinical care is III: 559 patients (431 females and 128 males, with an average age of 85.3 years) with lateral femoral neck fracture. All patients were surgically treated with Gamma 3 standard nail (SGN). We evaluated preliminary X-rays to classify fractures, according to AO-OTA classification and post-operative X-ray to verify cephalic screw position site, according to areas described by Cleveland in 1959: we measured tip-to-apex distance (TAD) and tip-to-apex calcar referred distance (CalTAD). Finally Chang reduction quality criteria (CRQC) for fracture reduction of trochanteric fractures were determined using preoperative or postoperative Antero-Posterior (AP) and lateral radiographs in a Picture Archiving and Communication System (PACS). Incidence of cut-out was evaluated in relation with these parameters. Patients were divided into 2 groups: first group had cephalic screw in optimal positions (5-8-9), the other group had cephalic screw in other positions.

RESULTS

In 328 patients (58.7%) screw was in positions 5-8-9, in 231 patients (41.2%) screw was in not-optimal position. Median TAD was 19.1 ± 7.0 mm (range = 0.0-50.5); in 463 patients (82.8%) TAD was ≤ 25 mm. Median CalTAD was 21.4 ± 4.7 mm (range = 5.7-39.2); in 105 patients (79.4%) CalTAD was ≤ 25 mm. Cut-out was observed in 8 cases (1.43%). Multivariate analysis showed a significant correlation (p < 0,05) between incidence of cut-out and fracture type 31A2 and with TAD values >25 mm. Cephalic screw position did not influence incidence of cut-out.

DISCUSSION

In order to obtain fracture healing with a low risk of failure, in particular cut-out, it is necessary to obtain good reduction of fracture and optimal lag screw position in order to achieve a TAD inferior to 25 mm.

Evolution and New Generation of Dual Mobility Cups

Although total hip arthroplasty (THA) is considered a successful procedure, hip dislocation remains the main cause of early failure. Dual mobility cups (DMCs) have been shown to significantly reduce the dislocation rate in both primary and revision THAs. During the past several decades, DMCs have evolved in design and fixation interface. There have been three generations of DMCs. This article addresses the rationale for a new cementless highly porous titanium DMC to improve component fixation and implant biocompatibility. [Orthopedics. 2023;46(5):e273-e280.].

Modular dual mobility articulation in primary and revision hip arthroplasty: lights and shadows

PURPOSE

The use of dual mobility cups in total hip arthroplasty has gained popularity in light of the fact it enables to reduce dislocation through increased jumping distance (JD) and impingement-free arc of movement. Modular Dual Mobility Cup (modular DMC) systems have been recently introduced to enable the use of dual mobility cups with standard metal-backed shells. The objective of this study was twofold: calculate the JD for each modular DMC system and conduct a systematic literature review to report clinical outcomes and reasons for failure of this construct.

METHODS

The JD was calculated using the Sariali formula: JD = 2Rsin [(π/2 - Ψ - arcsin (offset/R))/2]. A qualitative systematic literature review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. A comprehensive search for English and French articles between January 2000 and July 2020 was run on PubMed, EMBASE, Google Scholar, and Scopus with the primary objective of finding articles about modular DMC systems.

RESULTS

We identified eight 8 different manufacturers of modular DMC systems and 327 publications on the subject. After screening for duplicates and eligibility, we identified 229 publications: 206 articles were excluded because they contained no reports on modular DMC systems, whereas other three were not included because they focused on biomechanical aspects. Among the 11 included articles, 2 were prospective case series, 9 were retrospective case series. True dislocation occurred in 25 cases (0.9%), and six of them were solved by closed reduction without necessity of revision, while all 5 intraprosthetic dislocations were operated.

CONCLUSIONS

Modular DMCs are a valid method to deal with complex THA instability, with good clinical and patient-reported outcomes, low complication rates, and low revision rates at early follow-up. We would advise cautious optimism on the role of modular DMC implants, as it seems safer to use ceramic instead of metallic heads whenever possible to avoid the increase cobalt and chromium trace ion serum levels.

Use of dual-mobility cup in primary total hip arthroplasties: an Italian regional register (RIPO) study on three thousand, seven hundred and ten cases

PURPOSE

The purpose of the study was to investigate the outcome of dual-mobility cup (DM) compared with a standard cup (SC) in primary total hip arthroplasty (THA) in the long-term follow-up based on a regional Italian joint registry (RIPO).

METHODS

The Registry of Prosthetic Orthopaedic Implant (RIPO) was consulted, looking for all primary THAs implanted from 2000 to 2019. Three thousand seven hundred ten were dual-mobility cup (DM) total hip arthroplasties (THA) and 85.816 were standard cup (SC) THAs, on a total of 89.526 primary THA. Demographics, survival rates and causes of revision were evaluated and compared between the two groups.

RESULTS

The use of DM progressively increased from 0.4% in 2000 to 7.5% in 2018 of all primary THAs. Revision rate was 3.5% (128 on 3710) for DMC and 4.7% (4061 on 85,816) for SC. DM presented lower dislocation rate if compared to SC with 22-28-mm femoral head diameter. However, DM showed a higher risk of revision for any causes than SC with 32-mm femoral head diameter in long-term follow-up. Nevertheless, no significant difference was measured in terms of demographics and surgical approach for dislocation rate.

CONCLUSIONS

The DM cup represents a valid implant solution and has a lower dislocation rate than 22-28-mm SC. A slight increase in the use of DM implants over time was observed in the RIPO. However, a larger population and a longer follow-up are needed to further monitor the survival rate of new-generation DM implants.

Intra-Articular Calcaneal Fractures: Comparison between Mini-Invasive Approach and Kirschner Wires vs. Extensive Approach and Dedicated Plate-A Retrospective Evaluation at Long-Term Follow-Up

INTRODUCTION

Calcaneal fractures (CF) are the most common tarsal fractures, representing up to 75% of foot fractures and 2% of all fractures. The aim of this retrospective study is to analyze fixation with Kirschner wires through a mini-invasive approach and dedicated plate and screws through an extended approach at long-term follow-up.

MATERIALS AND METHODS

Patients were radiographically and clinically evaluated at final follow-up, by using the validated American Orthopedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot score for the clinical-functional assessment, the Short-Form 12 (SF-12) for the physical and psychological domain assessment, and the Visual Analog Scale (VAS) for pain.

RESULTS

In total, 38 patients (42 CF) met the inclusion criteria and were retrospectively evaluated and divided into two groups (Kirschner group and plate group) consisting of 19 patients each. The overall mean follow-up was 59.4 ± 11.8 months. The average values of the post-operative clinical outcomes of the two groups KG and PG were, respectively, 70.7 ± 11.9 and 70.1 ± 10.9 (AOFAS), 45.7 ± 6.8 and 46.5 ± 10.8 (SF-12 PCS), 54.7 ± 9.9 and 50.9 ± 11.8 (SF-12 MCS) at the final follow-up.

CONCLUSIONS

The present study showed that in the cases analyzed, the two surgical approaches used for the treatment of CF achieved comparable clinical outcomes. The only substantial difference found between the two groups of patients was the re-intervention rate that afflicted them.

Italian Consensus Conference on Guidelines for preoperative treatment in acetabular fractures

Preoperative management of acetabular fracture is a major problem and no consensus has been reached in literature on the optimal treatment of this problem. We present the results of the First Italian Consensus Conference on Acetabular fracture. An extensive review of the literature has been undertaken by the organizing committee and forwarded to the panel. Members were appointed by surgical experience with acetabular fractures. From November 2017 to January 2018, the organizing committee undertook the critical revision and prepared the presentation to the Panel on the day of the Conference. Then 11 recommendations were presented according to the 11 submitted questions. The Panel voted the recommendations after discussion and amendments with the audience. Later on, a second debate took place in September 2018 to reach a unanimous consent. We present results of the following questions: does hip dislocation require reduction? Should hip reduction be performed as soon as possible? In case of unsuccessful reduction of the dislocation after attempts in the emergency department, how should it be treated? If there is any tendency toward renewed dislocation, how should it be treated? Should Computed Tomography (CT) scan be performed before reduction? Should traction be used? How can we treat the pain? Is preoperative ultrasound exam to rule out vein thrombosis always necessary? Is tranexamic acid intravenous (IV) preoperatively recommended? Which antibiotic prophylactic protocols should be used? Is any preoperative heterotopic ossification prophylaxis suggested? In this article we present the indications of the First Italian Consensus Conference: a hip dislocation should be reduced as soon as possible. If unsuccessful, surgeon may repeat the attempts optimizing the technique. Preoperative CT scan is not mandatory before reduction. Skeletal traction is not indicated in most of the acetabular fracture. Standard pain and antibiotic prophylactic protocols for trauma patient should be used. Preoperative ultrasound exam is not recommended in all acetabular fracture. Tranexamic acid should be preoperatively used. There is no indication for preoperative heterotopic ossification.

Dual mobility cup in hip arthroplasty: an in-depth analysis of joint registries

Although total hip arthroplasty (THA) has shown successful results, instability remains a major complication. In recent years, dual mobility cups (DMC) have gained interest among clinicians thanks to its low rate of dislocation and good clinical results. The main aim of this work was to describe the accuracy of data on DMC from national and regional joint registries (JRs) and the available worldwide literature. We identified topics on DMC among JRs to propose a new harmonized and standardized section for DMC with the aim to understand its surveillance over the time. We extracted survival and implant data for a separate analysis. After performing a critical exclusion process, nine joint registries were considered eligible and included for final synthesis; these were the results from the available worldwide data from Joints Registries (JRs). In our study, eight analysed JRs reported a slight increase in DMC use in the last decade. In all the JRs evaluated and the available articles, dislocation remains one of the main reasons for revision and re-revision in hip arthroplasties. DMC is considered a valid construct increasingly used worldwide in primary and revision THA with the primary aim of reducing dislocation rates. Annual reports from JRs collect heterogeneous and low-quality information about outcomes and surveillance of DMC, creating a burden for clinicians to extract comparable data from different JR. Longer follow-up and a systematic registering of DMCs with international registry harmonization are needed to monitor DMC outcomes.

Rhizarthrosis Bilateral – Trapeziectomy Versus Arthroplasty with Dual Mobility Prosthesis: Case Report

Background: The trapeziometacarpal joint is the second joint affected by osteoarthritis in the hand. The symptoms and clinical presentation are characterized by pain, limited range of motion, muscle weakness with loss of strength, bone deformities and disability. The symptomatology often is not related to the radiographic grade of osteoarthrosis. Therefore, in addition to the radiographic stage of the disease, the treatment is influenced by multiple variables such as age, functional requirement, symptoms and stability of the joint. Objective: There are several options of surgical treatments. Although trapeziectomy and its technical variation is the gold standard for treatment, prosthesis replacement can be used with good results. This case report discusses the case of a 70-year-old male who presents bilateral trapeziometacarpal osteoarthrosis treated with two different techniques with different timelines. Methods: The patient underwent a trapeziectomy on the right hand and arthroplasty with implant on the left. In both TMC the stage of the disease was grade III according to the Eaton Litter classification and the results were evaluated according to clinical and radiographic criteria. The NPRS pain scale and the Quick Dash functional scale were used in subsequent checks. The mean follow-up was 12 months. Conclusion: There were no significantly different results with respect to pain, activities of daily living, mobility or strength. No complications were observed. The patient is satisfied with the treatment having found a better and earlier resumption of daily activity of the left hand treated with prosthesis replacement.

Revision of a Monoblock Metal-on-Metal Cup Using a Dual Mobility Component: Is It a Reasonable Option?

Revision of large-diameter, monoblock acetabular components for both hip resurfacing arthroplasty and metal-on-metal (MoM) total hip arthroplasty (THA) is correlated to a high amount of complications. For this reason, performing a limited revision by conversion to a dual mobility (DM) without acetabular component exchange has been proposed in order to limit these complications. Although DM bearing offers an easy solution avoiding the intraoperative and time-associated complications, concern about polyethylene wear and stability remains due to the difference regarding the design, the coverage angle and the clearance of the two implants. In order to evaluate the performance of this new solution with the new material to prevent the possibility of failure it is essential to conduct a review of the literature A qualitative systematic review of the literature has been conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. A comprehensive search of PubMed, EMBASE, Google Scholar, and Scopus for English and French articles between January 2000 and October 2019 was performed, with the primary objective of finding articles about dual mobility bearing coupling with large metal-on-metal cup in the case of hip revision procedure. Various combinations of the key words were used in the search strategy. Thirteen articles with DM bearing mated with MoM cup were analyzed. Of the 130 hip revisions selected, with a follow-up from 6 to 53 months, there were a total of 14 with complications (10.77%): four true dislocations (3.08%); six intra-prosthetic dislocations (IPD, 4.6%), two of which presented plastic deformation and polyethylene wear; four other complications (3.08%), included a cup osteolysis, a clicking noise, a superficial infection and a periprosthetic fracture. All the mentioned true dislocations occurred during the first month while IPDs appeared during the first two years from the index revision. In conclusion, according to the literature analyzed, we can stress that the concerns and doubts about mating a DM bearing with large MoM cup cannot be dissolved. It has been pointed out that a DM bearing is not designed for a MoM cup; it is not mechanically tested on MoM cups, which presents different clearance and coverage angles. Predictable complications may occur, such as IPD, polyethylene wear and true dislocation. These complications have been reported at an even higher rate than they were in the eighties, when the first generation of DM implants were of a lower quality of polyethylene and the characteristic of the design was less optimal than modern ones.

Neglected pulmonary thromboembolism in a traumatic anterior hip dislocation: A case report

We report the case of treatment delay for an early onset of pulmonary embolism due to thrombosis in the femoral vein occurred in a traumatic anterior hip dislocation. Mistakes interpretations of clinical findings and pre-operative chest CT-angiography has endangered our patient's life because of the medical report was focused only on acute traumatic injuries. After all, we were not able to find in the literature any similar report that could explain the pathogenesis of this early onset and help us in the patient management. We have tried to list a number of practical suggestions to use in emergency room in these situations.

Pilon fractures: A new classification system based on CT-scan

Actually, pilon fractures are classified according to AO and Ruedi Allgower classification systems based on X-rays. These classifications are less reproducible and do not provide necessary information for proper surgical planning. Aim of the study is to (1) propose a new classification system based on CT scan; (2) to check the prognostic value of this classification and (3) to evaluate its reliability and (4) reproducibility. We retrospectively reviewed 71 cases of pilon fracture. All fractures were classified according to AO, Ruedi Allgower and new proposed classification system by 5 surgeons. Clinical and radiographic evaluation were performed at a mean follow-up of 36 months. Cohen's K value was calculated in order to evaluate the interobserver and intraobserver agreement. Sixty-four of 71 fractures healed. Average AOFAS score was 91,7±7,8 in the Type I of new classification proposed, 87,7±7,8 in the Type II, 82±18,6 in type III, and 67,2±20,9 in type IV. Using the AO classification system the average K weighted value among the five reviewers was 0,51; using Ruedi Allgower classification it was 0,50 and using the new classification system it was 0,88 (p<0.0005). This study demonstrated that the new classification system is prognostic, reliable and reproducible. Moreover it provides a new treatment-oriented classification for this challenging fracture which affect the quality of life of the patients more than chronic diseases like diabetes and coronaropathy or pelvic fractures.

An uncommon case of irreducible ankle fracture-dislocation: the "Bosworth-like" tibio-fibular fracture

An irreducible ankle-fracture dislocation characterized by the dislocation of the proximal fragment of the fibula posteriorly to the tibial tubercle is defined as "Bosworth injury". In the present report it is described, for the first time in literature, a complex case where the Bosworth injury was associated to a tibial plafond fracture: the proximal fibular fragment was entrapped between the tibial pilon and the fractured posterior tibial tubercle, which acted as a clamp, thus avoiding ankle reduction. Due to the presence of the tibial fracture, it was not possible to observe the typical radiological signs of Bosworth injury and therefore two unsuccessful reductions were attempted before performing a CT scan that revealed the complexity of the case, that required an immediate ORIF procedure to prevent the onset of complications.

Opening-wedge high tibial osteotomy: a seven - to twelve-year study

PURPOSE

medial opening-wedge osteotomy is a widely performed procedure used to treat moderate isolated medial knee osteoarthritis. Historically, the literature has contained reports showing satisfactory mid-term results when accurate patient selection and precise surgical techniques were applied. This study was conducted to investigate the clinical and radiographic seven- to twelve-year results of opening-wedge high tibial osteotomy in a consecutive series of patients affected by varus knee malalignment with isolated medial compartment degenerative joint disease.

METHODS

we reviewed a case series of 147 medial opening-wedge high tibial osteotomies at an average follow-up of 9.5 years. Endpoints for evaluation included the reporting of adverse effects, radiographic evidence of bone union, radiographic changes in the correction angle during union, and clinical and functional final outcomes.

RESULTS

good or excellent results were obtained in 94% of the cases: the patients reported no major complications related to the opening-wedge high tibial osteotomy surgical technique, bone graft resorption, implant choice or postoperative rehabilitation protocol. At final follow-up, the average hip-knee angle was 4° of valgus without major loss of correction during the healing process. A statistically significant change in the patellar height was detected postoperatively, with a trend towards patella infera.

CONCLUSIONS

medial opening-wedge high tibial osteotomy is still a reliable method for correcting varus deformity while producing stable fixation, thus allowing satisfactory stability, adequate bone healing and satisfactory mid- to long-term results.

LEVEL OF EVIDENCE

Level IV, therapeutic cases series.

Prospective multi-centre study on a composite ceramic femoral component in total knee arthroplasty: Five-year clinical and radiological outcomes

BACKGROUND

Enhanced wear resistance of ceramics in general and improved mechanical characteristics of composite ceramics in terms of strength and resistance meet the demands for application in TKA. The aim of this prospective international multi-centre study was to evaluate the 5-year clinical and radiological outcomes of an unconstrained TKA with a composite ceramic femoral component.

METHODS

A total of 107 patients (109 knees) underwent TKA with the MULTIGEN-PLUS Ceramic Knee at seven centres in three European countries. Clinical and radiological assessments were performed preoperatively and postoperatively at 3, 12, 24 and 60 months, using HSS, WOMAC, SF-36 and standardised radiographs.

RESULTS

Mean HSS and WOMAC increased significantly from 55.1±11.5 (21-83) and 48.1±16.6 (3-90) preoperatively to 85.6±9.6 (49-98) and 73.3±20.4 (17-100) at 60 months. Mean SF-36 showed significant improvements in patients' quality of life (49.1±17.6 (12-96) preoperatively versus 67.7±23.1 (12-100) at 60 months). Non-progressive radiolucent lines (<1 mm) were observed around the femoral component in four cases. Neither implant migration nor loosening were registered. Kaplan-Meier survivorship was 96.0% at 60 months (92.1-100%, CI 95%).

CONCLUSIONS

Five-year implant survival rate of the ceramic knee is comparable to other metallic and ceramic unconstrained TKA systems. Although the assessment of long-term implant survivorship is still pending, the ceramic implants represent a promising solution for patients with allergies against metallic components and furthermore for the general osteoarthritis population due to enhanced wear resistance.

Trabecular orientation in the human femur and tibia and the relationship with lower-limb alignment for patients with osteoarthritis of the knee

Wolff׳s Law suggests that the orientation of trabeculae in human bone changes in response to altered loading patterns. The aim of this study was to investigate trabecular orientation in both the femur and tibia and to compare this with the mechanical axis of the leg. The study involved analysis of radiographs from patients with osteoarthritis of the knee (n=91). For each patient, the trabecular orientation in both the distal femur and proximal tibia was measured from a standard anteroposterior radiograph of the knee and the mechanical axis of the leg was calculated from a long leg view taken while weight bearing. There was a significant correlation between the mechanical axis and the trabecular orientation in each of the regions considered in the femur (r=-0.41, -0.30, 0.52, and 0.23) and tibia (r=-0.27 and 0.31). Multiple regression analysis, with mechanical axis as the dependent variable, produced an R(2) of 0.62. Greater trabecular anisotropy (i.e. greater alignment) was observed in the medial femur and tibia compared to the lateral side (p<0.01). The results give an insight into the trabecular changes that may take place during development of osteoarthritis and following surgery. In particular, we propose that the orientation of the trabeculae in both the distal femur and proximal tibia will reflect the angle of mechanical loading through the knee.

Two-stage reimplantation for periprosthetic knee infection: Influence of host health status and infecting microorganism

BACKGROUND

Two-stage revision is the gold standard treatment of TKA infection; nevertheless various factors may influence the success rate. The aim of our study was to assess the impact of the number of patient comorbidities together with virulence of infectious organism on prognosis of two-stage revision procedure in chronic peri-prosthetic knee infection; moreover we tried to demonstrate correlation between the presence of positive culture during re-implantation and re-infection rate.

METHODS

Thirty-eight cases of two-staged revision procedures for infected total knee arthroplasty were prospectively followed. The presence of high virulence microorganisms on the culture result and the number (more than three) of comorbidities were used as major risk factors. All cases were divided into three groups: Group 1 (10 patients without major risk factors), Group 2 (18 patients with only one major risk factor), Group 3 (10 patients with both of major risk factors).

RESULTS

After a mean follow-up of 65months (range 24-139months), there was infection recurrence in nine cases: four re-infections occurred with the same organism while five patients had re-infection with a different organism. Recurrence was higher in Group 3 (33% of the cases), lower in Group 2 (12% of the cases), whereas no infection occurred in Group 1. Finally in case of positive intraoperative cultures recurrence rate was 83%, whereas when specimens were negative we had only 12.5% of re-infections.

CONCLUSIONS

Even if standard protocol of two-stage revision has demonstrated good results when treating low-virulence infections or patients without associated risk factors, its application to more challenging condition cannot be assumed.

LEVEL OF EVIDENCE

Level IV, therapeutic study. See the Guidelines for Authors for a complete description of level of evidence.

Computer-assisted surgery as indication of choice: total knee arthroplasty in case of retained hardware or extra-articular deformity

PURPOSE

The use of traditional cutting guides during knee arthroplasty in some cases could be extremely difficult, if not impossible, because of angular deformities, IM sclerosis, long-stemmed hip implants, or hardware within the femoral canal that cannot be removed. In these difficult cases navigation-assisted knee arthroplasty should be considered as an effective and appealing option.

METHODS

We present 14 cases in which ideal mechanical and prosthetic alignment was achieved with different image-free, computer-assisted navigation systems, because of an extra-articular deformity (group A, nine patients) or because of a retained implant or hardware (group B, five patients).

RESULTS

After a mean follow-up of 28 months (range 12-53 months), the average knee score increased overall from a mean of 33 points (range 12-63) to 78 points (range 63-90). The average functional score improved from a mean of 32 points (range 10-65) to 72 points (range 40-90). The postoperative mechanical axis ranged between 3° of varus and 3° of valgus. There was an implant revision in one patient who had a traumatic rupture of medial collateral ligament, which occurred 27 months after the index procedure.

CONCLUSIONS

Based on our results we think that the navigation-assisted technique provides an alternative approach to the traditional instrumentation for treating these difficult patients in an effective and less invasive manner.

Ceramic femoral components in total knee arthroplasty - two year follow-up results of an international prospective multi-centre study

Background:

Total knee arthroplasty can be considered as a reliable surgical procedure with a good long-term clinical result. However, implant failure due to particle induced aseptic loosening as well as the aspect of hypersensitivity to metal ions still remains an emerging issue.

Methods:

The purpose of this prospective international multi-centre study was to evaluate the clinical and radiological outcomes and the reliability of the unconstrained Multigen Plus Total Knee System with a new BIOLOX® delta ceramic femoral component. Cemented total knee arthroplasty was performed on 108 patients (110 knees) at seven hospitals in three countries. Clinical and radiological evaluations were performed preoperatively, and after 3, 12 and 24 months postoperatively using the HSS-, WOMAC-, SF-36-score and standardised X-rays.

Results:

The mean preoperative HSS-Score amounted to 55.5 ± 11.5 points and improved significantly in all postoperative evaluations (85.7 ± 11.7 points at 24 months). Furthermore, improvements in WOMAC- and SF-36-score were evaluated as significant at all points of evaluation. Radiolucent lines around the femoral ceramic component at 24 months were found in four cases. Progression of radiolucent lines was not seen and no implant loosening was observed. During the 24 month follow-up eight patients underwent subsequent surgery due to reasons unrelated to the implant material.

Conclusions:

The observed clinical and radiological results are encouraging for a long-term survival of the ceramic femoral component. Therefore, ceramic implants could be a promising solution not only for patients with allergies against metallic implant materials, but also for the osteoarthritic knee joint. Long-term follow-up is necessary to draw conclusions regarding the superiority of the ceramic knee implants concerning in vivo wear and long-term survivorship.

Total knee arthroplasty for post-traumatic proximal tibial bone defect: three cases report

Bone stock deficiency in primary as well as in revision total knee arthroplasty (TKA) represents a difficult problem to surgeon with regard to maintaining proper alignment of the implant components and in establishing a stable bone-implant interface. Different surgical procedures are available in these situations, for instances the use of bone cement, prosthetic augments, custom implant, and wire mesh with morsellized bone grafting and structural bone allograft. Structural allograft offers a numerous advantages as easy remodeling and felling cavitary or segmental defects, excellent biocompatibility, bone stock restoration and potential for ligamentous reattachment. In this article we report a short term result of three cases affected by severe segmental medial post/traumatic tibial plateau defect in arthritic knee, for which massive structural allograft reconstruction and primary total knee replacement were carried. The heights of the bone defect were between 27-33 mm and with moderate medio-lateral knee instability. Pre-operative AKS score in three cases was 30, 34 and 51 points consecutively and improved at the last follow-up to 83, 78 and 85 consecutively. No acute or chronic complication was observed. Last radiological exam referred no signs of prosthetic loosening, no secondary resorption of bone graft and well integrated graft to host bone. These results achieved in our similar three cases have confirmed that the structural bone allograft is a successful biological material to restore hemi-condylar segmental tibial bone defect when total knee replacement is indicated.

Gap balancing versus measured resection technique using a mobile-bearing prosthesis in computer-assisted surgery

Navigation has been developed to help surgeons install implants more accurately and reproducibly; at the same time, this tool is able to record quantitative information such as joint range of motion, laxity and kinematics intra-operatively. As for standard surgery, two strategies are possible to achieve either femoral component rotation or overall prosthetic alignment: a measured gap resection approach, in which bone landmarks are used to guide resections equal to the distal and posterior thickness of the femoral component, or a gap-balancing technique, in which equal collateral ligament tension in flexion and extension is tried to find before as a guide to final bone cuts. The purpose of this paper is to compare the two different methods in a 67 patients group submitted to the same procedure using mobile-bearing (MB) prosthesis in order to analyse the effect of both techniques on joint line maintenance, axial limb restoration and components position. The gap group (GG) consists of 31 patients in whom the arthroplasty was performed using a navigated gap-balancing technique. The measured group (MG) consists of 36 patients in whom a computer-assisted measured resection technique was used. The results of imaging and the number of outliers were not statistically different (P = 0.56) for the mechanical axis and prosthetic positioning between the two groups. The gap technique showed a statistically significant alteration of the post-operative value when compared with the measured resection technique, (P = 0.036). The mean elevation of the joint line was 4.09 mm for the GG and 3.50 mm in the MG.

Total knee arthroplasty in stiff knee compared with flexible knees

This retrospective study was done to evaluate the results of total knee arthroplasty performed on 32 patients with stiff knee, having a preoperative arc of movement between 0° and 50° (average 30°). This group of patients were matched with a group of 32 flexible knees, randomly selected from the same cohort of patients who underwent knee arthroplasty in our ward. At a mean follow-up of 4.5 years (min 2, max 11 years), seven patients of the stiff group reported complications (21.8% overall): four prosthetic infection that successively underwent removal of the implant, one skin necrosis 4 months after the intervention, one early contracture and one late stiffness of the knee. In the control group, in two cases, there was substitution of the implant due to periprosthetic infection. At the end of the study period, the clinical evaluation was not possible in four patients of the stiff and in two patients of the control group who underwent revision of the prosthetic components. An excellent or good clinical result was obtained in 92% of stiff group and in 96% of the control group patients. Although the final results achieved in these patients are worse than those of patients with flexible knee due to disadvantageous preoperative conditions and high complication rate, our results demonstrate the efficacy of the arthroplasty procedure as treatment of stiff knee.

Three-dimensional analysis of image-free navigation system for total knee arthroplasty

Malalignment causes abnormal forces that may lead to loosening after knee replacement. Whether a computer-assisted technique can improve the precision of implant positioning guaranteeing good long-term results in total knee arthroplasty, this is a matter of discussion. The authors evaluate the alignment accuracy of 20 primary total knee arthroplasties, performed using an image-free computer navigation systems, with standardized CT protocol and three-dimensional digital model reconstruction. The results of this study demonstrate that the image-free navigation system is able to improve accuracy in axial limb alignment and positioning of the components in the majority of cases; moreover, the difference between the mean mechanical axis value of the navigation system (179.7° ± 1.7°) and the median mean value obtained during the post-operative evaluation (180.3° ± 1.9°) is not statistically significant (P = 0.28).

Comparison between two computer-assisted total knee arthroplasty: gap-balancing versus measured resection technique

Two surgical strategies are possible in total knee arthroplasty (TKA): a measured resection technique, in which bone landmarks are used to guide resections equal to the distal and posterior thickness of the femoral component, or a gap-balancing approach, in which equal collateral ligament tension in flexion and extension is sought before and as a guide to final bone cuts. In this study performed with computer assisted system, we compared the 2 different methods in 126 patients followed prospectively in order to analyze the effect of both the techniques on joint-line (JL) maintenance, axial limb restoration and components position. The gap technique showed a statistical increase in the post-operative value when compared with the measured resection technique, (P = 0.008). When comparing the two groups regarding to the pre-operative deformity, we have found a statistical difference (P = 0.001) in case of moderate pre-operative deformity (less than 10 degrees), and the measured resection technique showed a slight superiority in preserving a joint line more faithful to the pre-operative. We found an ideal alignment for the mechanical axis (180 degrees ± 3 degrees) (95% of cases). In six cases (5%), the mean post-operative value exceeded (varus or valgus) the ideal value by more than 3 degrees. In the frontal plane, a good alignment was observed for both femoral and tibial components without a significant difference between the two techniques. In the sagittal plane was found more alignment variability due to the different implants used and their ideal starting slope, from 7 degrees to 3 degrees. Finally, the surgeon can use the approach with which he has more confidence; however, as the measured resection technique causes less reduction in the post-operative joint-line position, in case of shortening of patellar tendon or patella infera, this technique is preferable.

The potential role of metal ion release as a marker of loosening in patients with total knee replacement

We investigated the role of ion release in the assessment of fixation of the implant after total knee replacement and hypothesised that ion monitoring could be a useful parameter in the diagnosis of prosthetic loosening. We enrolled 59 patients with unilateral procedures and measured their serum aluminium, titanium, chromium and cobalt ion levels, blinded to the clinical and radiological outcome which was considered to be the reference standard. The cut-off levels for detection of the ions were obtained by measuring the levels in 41 healthy blood donors who had no implants. Based on the clinical and radiological evaluation the patients were divided into two groups with either stable (n = 24) or loosened (n = 35) implants.

A significant increase in the mean level of Cr ions was seen in the group with failed implants (p = 0.001). The diagnostic accuracy was 71% providing strong evidence of failure when the level of Cr ions exceeded the cut-off value. The possibility of distinguishing loosening from other causes of failure was demonstrated by the higher diagnostic accuracy of 83%, when considering only patients with failure attributable to loosening.

Measurement of the serum level of Cr ions may be of value for detecting failure due to loosening when the diagnosis is in doubt. The other metal ions studies did not have any diagnostic value.

Anterior decompression and plate fixation in fracture dislocations of the lower cervical spine

Surgical treatment of unstable traumatic injuries of the cervical spine can be carried out by a posterior or anterior approach, with different advantages and disadvantages. Twenty patients were treated with anterior decompression, interbody fusion with autogenous iliac bone graft, and osteosynthesis with a Louis anterior plate. The screws were inserted in the vertebral body without reaching the posterior vertebral wall. There were 18 male and 2 female patients, aged between 18 and 66 years (average 36 years). The osteoarticular lesion was in 8 cases a tear-drop fracture and in 12 a fracture-dislocation. The mechanisms of injury were flexion-compression, flexion-rotation, hyperflexion, and hyperextension. A complete spinal cord lesion was present in 10 cases, central cord syndrome in 5, isolated radiculopathy in 3, and anterior cord syndrome in 1; one patient had normal neurological function. At long-term followup fusion of the graft was observed in all cases without evidence of spinal malalignment, breakage of the implant, or aseptic hardware loosening. Neurological deterioration was not observed in any case. In one case, complicated by late infection, healing was uneventful after plate removal, surgical debridement, and antibiotic therapy. A fistula of the hypopharynx due to perforation of the piriform recess appeared following repeated bronchoscopy 12 months after surgery. There were no signs of implant loosening and the lesion was surgically repaired. From a neurological point of view the 10 patients with complete cord lesion remained unchanged; those with incomplete cord lesions improved by 1 or 2 degrees on the Frankel scale; those with isolated radiculopathies recovered fully; and the neurologically intact patient remained unchanged. The present study and the data reported in the literature prove that anterior surgery with plate fixation in cervical spine injuries allows the achievement of complete neural decompression by direct visual examination. On the other hand, posterior surgery can result in incomplete decompression and associated neurological deterioration. Anterior plate instrumentation has proved itself mechanically adequate, even if it is less stable than posterior constructs. The advantages of anterior surgery compared to those of posterior surgery are such that several specific risks are acceptable. Posterior surgery is nevertheless indicated if the lesion cannot be reduced preoperatively under closed conditions.

Early aseptic loosening of a porous tantalum knee prosthesis

Porous tantalum represents a relatively new solution for primary and revision total knee arthroplasty, offering several unmatched properties. Tantalum is a transition metal, with excellent biocompatibility and bioactivity due to its intrinsic physical and structural characteristics. A widespread clinical use of porous tantalum tibial components for primary total knee arthroplasty has been partly hindered by the difficulty in removing this type of implant after bone in growth, often leading to a significant bone defect. On the contrary, in the case here reported, removal of the trabecular metal tibial component was unexpectedly easy at a 7-month follow-up due to the absence of bone ingrowth but with a complete preservation of the tibial plate bone stock. Causes for the lack of bone ingrowth are discussed.

Total knee arthroplasty in patients with poliomyelitis

We performed a retrospective chart and radiograph review of 10 patients with a history of poliomyelitis involving a limb that subsequently underwent primary total knee arthroplasty between 2000 and 2008. One posterior stabilized (PS), two condylar constrained (CCK), and seven rotating hinge (RHK) prostheses belonging to the same system were implanted. Eight patients were followed for a minimum of 2 years (mean 4.3 years, range 2 to 8.5 years); one patient required revision for prosthesis infection. The last patient was followed for just six months reporting excellent pain relief, and without complications. American Knee Society Score (AKSS) improved postoperatively in all eight patients with at least 2 years follow-up. The improvement was more marked for the knee score, which increased from a mean of 37 points preoperatively (range 20 to 51) to 75.7 points postoperatively (range 50 to 92); for the functional score the mean increase was only 15.8 points, from a mean of 38.5 points (range 20 to 70) to 54.3 points (range 20 to 80) after the intervention. One patient had a recurrence of the recurvatum deformity after implanting a CCK prosthesis. We found that a rotating hinge prosthesis that allowed hyperextension was suitable treatment for patients with knee osteoarthritis and polio as this compensated for loss of quadriceps power.

LOW-POWER DIODE LASER STIMULATION OF SURGICAL OSTEOCHONDRAL DEFECTS: RESULTS AFTER 24 WEEKS

The purpose of this study was to evaluate osteochondral lesions of the knee, treated intraoperatively with low-power laser stimulation, and assess results at 24 weeks. Surgery was performed under general anesthesia on six rabbits; a bilateral osteochondral lesion was created in the femoral medial condyles with a drill. All of the left lesions underwent immediate stimulation using the diode Ga-Al-As laser (780nm), whereas the right knees were left untreated as control group. After 24 weeks, the explants from the femoral condyles, either treated employing laser energy or left untreated, were examined histomorphometrically. Results obtained on the lased condyles showed good cell morphology and a regular aspect of the repaired osteocartilaginous tissue.

Implant fixation in knee replacement: preliminary in vitro comparison of ceramic and metal cemented femoral components

Improved wear resistance in total knee replacement (TKR) is a suitable goal. Whereas the use of metal components is well established, mechanical loosening in recently introduced ceramic components are a cause of concern. The scope of this work was to test in vitro whether ceramic TKR femoral components are more prone to mechanical loosening than metal ones. Composite femurs were implanted with commercially available TKR metal components, and with ceramic components having identical shape to the metal ones. Implanted femurs were tested on a knee simulator for up to 5 x 10(-6) cycles. Inducible micromotions and permanent migrations were recorded throughout the test. The cement layers were inspected for signs of damage or fracture. Micromotions and migrations were similar for metal and ceramic components: their magnitude and trend over time indicated that no implant was becoming loose. When there were statistically significant differences, the ceramic components were more stable than the metal ones. When the cement layers were inspected, a few short cracks were observed; most such cracks appeared during the first cycles, while no further damage occurred in the rest of the test. The type of damage found for both the metal and the ceramic components is compatible with well-fixed implants after long-term cycling. Altogether, no remarkable difference was found between the metal and ceramic components. Therefore, this study rejects the hypothesis that ceramic TKR femoral components are more prone to mechanical loosening. Although this study had a limited sample size, it provides novel pre-clinical indications about the potential of ceramic TKR femoral components.

Trabecular metal patella in total knee arthroplasty with patella bone deficiency

This study evaluates results following patellar resurfacing using trabecular metal (TM) patella in marked deficiency or weakness of patellar bone that precludes patellar resurfacing with a standard cemented patellar button. Ten consecutive patients undergoing primary (3 cases) or revision (7 cases) total knee arthroplasty with patella augmentation were evaluated at a mean follow-up of 45 months (range 18-65). Nine patients had marked patellar bone deficiency and one had had previous patellectomy. No intra-operative complications occurred. There was no displacement of the patellar component and no patellar fractures when at least 50% of bone contact was possible. We observed loosening of the patella augmentation 17 months after the index procedure only in the case of previous patellectomy. When bone was present the fixation appeared excellent by radiographic evaluation already at 3 to 6 months after surgery; afterward bone contact was uniform in the peripheral regions in both lateral and Merchant radiographic views without signs of loosening. Finally, the mean Knee Society scores improved in all patients.

Preliminary experience with electromagnetic navigation system in TKA

Accuracy of implant positioning and precise reconstruction of leg alignment offers the best way to achieve good long-term results in total knee arthroplasty. Computer instrumentation was developed to improve the final position of the component and restore the mechanical axis. Current navigation systems use either optical or electromagnetic tracking. The advantage of the Electromagnetic (EM) navigation system is that no line-of-sight issues are present. However, special iron-free instruments are required. This report analyzes the postoperative radiological results of 32 knees treated using an EM system. All the measurements were recorded using software able to subtend angles automatically by five physicians, three radiologist and two orthopedic residents not involved with the surgery. Each radiograph was measured three times, in random order, and at delayed intervals. We found an ideal alignment for the mechanical axis (180+/-3 degrees ) in 30 out of 32 cases, whereas all the patients achieved a value of 90 degrees +/-3 degrees for both femoral and tibial frontal component angles. An apparently over-corrected implant position for the sagittal femoral component was reported, with a mean value of 11.2 degrees +/-3.6. The mean position of the tibial component was 90.6 degrees +/-2.8; just four measurements were outside of the +/-3 degrees of the desired value. EM is safe and there were no complications related to this system. An almost perfect correlation was found between the mechanical axis value of the EM navigation system (179.8 degrees +/-1.8) and the median value of the all reviewers (180.3 degrees +/-1.9) with a difference of 0.5 degrees .

Biological and biomechanical effects of vancomycin and meropenem in acrylic bone cement

Antibiotic-loaded bone cement is extensively used in joint arthroplasty, but increasing bacteria resistance against common antibiotics has lead to a demand for alternative drugs. However, bone cement containing new additives must be characterized both biologically and mechanically. This study evaluated elution kinetics, antibacterial activity, and mechanical properties for cement loaded with vancomycin and/or meropenem. The presence of meropenem broadened the antibacterial spectrum and enhanced the elution of vancomycin. The mechanical properties were negatively affected by 1.0 g of vancomycin, but these detrimental effects were acceptable when only 0.5 g of vancomycin were added to a cement containing 0.5 g of meropenem. Further investigations on this formulation with adjusted antibiotic amounts are, however, necessary to reach the optimal compromise between the antibacterial and the mechanical properties of the bone cement.

Long-term implant—bone fixation of the femoral component in total knee replacement

Success of total knee replacement (TKR) depends on the prosthetic design. Aseptic loosening of the femoral component is a significant failure mode that has received little attention. Despite the clinical relevance of failures, no protocol is available to test long-term implant—bone fixation of TKR in vitro. The scope of this work was to develop and validate a protocol to assess pre-clinically the fixation of TKR femoral components. An in vitro protocol was designed to apply a simplified but relevant loading profile using a 6-degrees-of-freedom knee simulator for 1 000 000 cycles. Implant—bone inducible micromotions and permanent migrations were measured at three locations throughout the test. After test completion, fatigue damage in the cement was quantified. The developed protocol was successfully applied to a commercial TKR. Additional tests were performed to exclude artefacts due to swelling or creep of the composite femur models. The components migrated distally; they tilted towards valgus in the frontal plane and in extension in the sagittal plane. The migration patterns were consistent with clinical roentgen-stereophotogrammetric recordings with TKR. Additional indicators were proposed that could quantify the tendency to loosen/stabilize. The type and amount of damage found in the cement, as well as the migration patterns, were consistent with clinical experience with the specific TKR investigated. The proposed pre-clinical test yielded repeatable results, which were consistent with the clinical literature. Therefore, its relevance and reliability was proved.

Controlled release of vancomycin from cross-linked gelatine

This paper explores the possibility of using biodegradable cross-linked gelatines as antibiotic devices for a long-term elution (80 days). Capillary electrophoresis (CE) has been utilized to evaluate the mass percentage of vancomycin and gelatine contemporary released from differently cross-linked vancomycin loaded gelatine samples in an elution time ranging from 24 to 1920 h. While the solubilization kinetic of gelatine samples differently cross-linked can be very close described by the simplified Higuchi model, the vancomycin release kinetic is contemporary governed by both the Fickian diffusion process trough the gelatine matrix network and the dissolution process of the matrix due to its degradation. Comparing the antibiotic eluting kinetics from gelatine at diverse cross-linking degree we observed that the degradation of the proteic matrix appears to have a minor influence in the drug release control. Vancomycin released from all the gelatine partially cross-linked samples results active against Staphylococcus aureus and Streptococcus faecalis which represent the most pathogens commonly isolated in orthopaedic infections. Vancomycin overcomes the minimum inhibitory concentration for both the bacteria in the whole range of elution time. Cross-linked gelatine devices appear to represent a useful biodegradable delivery system for local anti-infective therapy in arthoplasty.

Mechanical effects of the use of vancomycin and meropenem in acrylic bone cement

BACKGROUND

The increasing resistance of certain bacteria to antibiotics commonly used in bone cements has led to a demand for alternative antibacterial agents. The antibiotics added to bone cements may, however, have detrimental effects on the mechanical properties of the cement.

MATERIAL AND METHODS

We evaluated the mechanical effects of adding vancomycin and meropenem to bone cement by compression, bending and fatigue tests.

RESULTS

Addition of vancomycin at a concentration of up to 2.5% (w/w) had no effect on the compressive strength. Bending and fatigue strength were negatively affected by vancomycin but not by meropenem.

INTERPRETATION

A cement containing 1.25% vancomycin and 1.25% meropenem might be an interesting compromise between the introduction of antibacterial properties and preservation of the mechanical properties. With this concentration of additives the compressive strength and the fatigue strength remain unchanged, while the bending strength (-14%) and the bending modulus (-9%) are only slightly reduced and remain above the limits set by the ISO5833 standard.

Interlocking nail for femoral shaft fractures: is dynamization always necessary?

A series of 179 closed femoral fractures treated by static interlocking nailing (Grosse-Kempf nail) was reviewed to evaluate the effect of dynamization on the time to bony union. In 75 patients, dynamization was performed whereas in 104 the implant was left static. Union occurred in 178 patients. We observed one infection. Time to union was significantly shorter in the static group (103 days) compared to the dynamized group (126 days).

Heterotopic ossifications subsequent to knee arthroplasty

The occurrence of heterotopic ossifications constitutes a rare but possible complication in knee arthroplasty surgery. The authors retrospectively reviewed data for more than 250 patients submitted to knee arthroplasty with the purpose of ascertaining the incidence of the occurrence of heterotopic ossifications after surgery and of understanding any clinical repercussions and possible risk factors. A total of 14 cases of heterotopic ossifications were observed out of 276 knee arthroplasties (4.7%). Lesions were grade 1: 4, grade II: 3, grade III: 7. The authors stress the importance of local factors as compared to general ones and the need to adopt a respectful surgical method, avoiding notching or excessive trauma to the periosteum, as well as the need to define parameters in order to single out subjects at risk and in whom prophylaxis should be administered.