Patient-specific instrumentation in total knee arthroplasty: a review of the current literature.

Total knee arthroplasty (TKA) is one of the most frequently performed interventions in the field of Orthopaedic surgery. Over the last decades the implantation technique has improved continuously. The majority of patients is satisfied with the clinical outcome of TKA. However in various clinical follow-ups, up to 20% of unsatisfied patients can be observed. Periprosthetic infection and aseptic loosening seem to be the most common reasons for failure. Malalignment has been discussed as a cause of aseptic loosening and often leads to revision surgery. In order to increase the precision of implant positioning and alignment, new technologies such as patient-specific instrumentation (PSI) have been developed. Since the introduction of PSI, multiple clinical studies have been performed analyzing the clinical and radiological outcome of TKA with PSI technique. This review covers the recent literature of PSI in respect to surgical accuracy, clinical outcome, time- and cost-effectiveness.

Advances in fixation strength of reorienting rectangular triple pelvic innominate osteotomies - A biomechanical investigation of two screw fixation techniques.

BACKGROUND: Reorientating pelvic osteotomies are performed to prevent femoral-acetabular impingement or degenerative arthritis. A Toennis-Kalchschmidt triple pelvis innominate osteotomy is used in symptomatic patients. This study aimed to investigate the biomechanical behaviour of two different acetabular screw configurations for triple pelvis innominate osteotomy osteosynthesis. METHODS: Two screw-orientation techniques in rectangular os ilium osteotomy were compared by osteotomising 12 artificial hemipelvises with triple pelvis innominate osteotomy protocol (fragment reorientation: 10.5° inclination and 10.0° anteversion) and randomising them in 2 groups (n = 6) for implantation with three 4.5 mm screws. Bidirectional group had a bidirectional screw orientation and Monoaxial group had a monoaxial direction of all three screws through iliac crest. All specimens were tested under progressively increasing cyclic loading until failure. Group-wise comparisons of acetabular cup medialisation, anteversion and inclination were evaluated via motion tracking at cycles 250, 500, 750, 1000, 1250, 1500, 1750, 2000, 2250, and 2500. Failure was defined as reaching 5° inclination or 5° anteversion. FINDINGS: Acetabular cup medialisation (p ≤ 0.026), anteversion (p ≤ 0.021) and inclination (p ≤ 0.039) all increased significantly during testing in both groups. There were no significant differences for the group-wise comparisons at the cycle points defined in the methods (p ≥ 0.182). No significant differences were detected between groups for cycles to failure and failure load (p = 0.873). INTERPRETATION: Bidirectional screw alignment does not lead to significant advantages compared to pure monoaxial if all three axial screws are evenly distributed over the osteotomy geometry. The triple pelvis innominate osteotomy is susceptible to changes in anteversion, inclination and medialisation under partial weight-bearing. Cautious rehabilitation protocols are recommended.

Statistical Morphology and Fragment Mapping of Complex Proximal Humeral Fractures.

Background and Objectives: Proximal humerus fractures (PHFs) are common in the elderly, but the treatment results are often poor. A clear understanding of fracture morphology and distribution of cortical bone loss is important for improved surgical decision making, operative considerations, and new implant designs. The aim of this study was to develop a 3D segmentation fracture mapping technique to create a statistical description of the spatial pattern and cortical bone loss of complex PHFs. Materials and Methods: Fifty clinical computed tomography (CT) scans of complex PHFs and their contralateral intact shoulders were collected. In-house software was developed for semi-automated segmentation and fracture line detection and was combined with manual fracture reduction to the contralateral template in a commercial software. A statistical mean model of these cases was built and used to describe probability maps of the fracture lines and cortical fragments. Results: The fracture lines predominantly passed through the surgical neck and between the tuberosities and tendon insertions. The superior aspects of the tuberosities were constant fragments where comminution was less likely. Some fracture lines passed through the bicipital sulcus, but predominantly at its edges and curving around the tuberosities proximally and distally. Conclusions: A comprehensive and systematic approach was developed for processing clinical CT images of complex fractures into fracture morphology and fragment probability maps and applied on PHFs. This information creates an important basis for better understanding of fracture morphology that could be utilized in future studies for surgical training and implant design.

Biomechanical Comparison of Intramedullary Versus Extramedullary Implants for Fixation of Simple Pertrochanteric Fractures.

OBJECTIVES: To evaluate the biomechanical performance of the intramedullary TFN-ADVANCED Proximal Femoral Nailing System (TFNA) versus the extramedullary Femoral Neck System (FNS) for fixation of simple pertrochanteric fractures in a human cadaveric model. METHODS: Ten human cadaveric femoral pairs were implanted pairwise with either TFNA or FNS. A simple pertrochanteric fracture OTA/AO 31-A1 was created and all specimens were biomechanically tested under progressively increasing cyclic loading until failure. Interfragmentary and bone-implant movements were monitored by motion tracking. RESULTS: Axial stiffness was comparable between TFNA and FNS, P = 0.34. Similarly, varus deformation, femoral head rotation around neck axis and implant migration remained without significant differences between TFNA and FNS after 3000 cycles (800 N peak load), P ≥ 0.10. However, cycles to 15-mm leg shortening were significantly higher for TFNA versus FNS, P < 0.01. CONCLUSIONS: From a biomechanical perspective, with its current design, FNS does not seem to be a valid alternative to TFNA for treatment of simple pertrochanteric fractures.

Anatomical variation in humeri: gender and side comparison using statistical shape modelling.

PURPOSE: The surgical management of proximal humeral fractures remains challenging. Anatomical reduction of the fracture has been reported as the keystone for a sufficient surgical fixation and successful outcome. However, mostly there is no example of its premorbid state. Literature suggests that the mirrored contralateral side can be used as a reconstruction template. But is this a correct technique to use? The purpose of this study is to define anatomical variation between humeri based on gender and side comparison. METHODS: Two different statistical shape models of the humerus were created and their modes of variation were described. One model contained 110 unpaired humeri. The other model consisted of 65 left and corresponding right humeri. RESULTS: The compactness of the statistical shape model containing 110 humeri showed that two principal components explain more than 95% of the variation and the generalization showed that a random humerus can be described with an accuracy of 0.39 mm. For only three parameters, statistically significant differences were observed between left and right. However, comparing the mean of the different metrics on the humeri of men and women, almost all were significant. CONCLUSION: Since there were only small differences between left and right humeri, using the mirrored contralateral side as a reconstruction template for fracture reduction can be defended. The variable anatomy between men and women could explain why locking plates not always fit to the bone.

Locking Plates With Computationally Enhanced Screw Trajectories Provide Superior Biomechanical Fixation Stability of Complex Proximal Humerus Fractures.

Joint-preserving surgical treatment of complex unstable proximal humerus fractures remains challenging, with high failure rates even following state-of-the-art locked plating. Enhancement of implants could help improve outcomes. By overcoming limitations of conventional biomechanical testing, finite element (FE) analysis enables design optimization but requires stringent validation. This study aimed to computationally enhance the design of an existing locking plate to provide superior fixation stability and evaluate the benefit experimentally in a matched-pair fashion. Further aims were the evaluation of instrumentation accuracy and its potential influence on the specimen-specific predictive ability of FE. Screw trajectories of an existing commercial plate were adjusted to reduce the predicted cyclic cut-out failure risk and define the enhanced (EH) implant design based on results of a previous parametric FE study using 19 left proximal humerus models (Set A). Superiority of EH versus the original (OG) design was tested using nine pairs of human proximal humeri (N = 18, Set B). Specimen-specific CT-based virtual preoperative planning defined osteotomies replicating a complex 3-part fracture and fixation with a locking plate using six screws. Bone specimens were prepared, osteotomized and instrumented according to the preoperative plan via a standardized procedure utilizing 3D-printed guides. Cut-out failure of OG and EH implant designs was compared in paired groups with both FE analysis and cyclic biomechanical testing. The computationally enhanced implant configuration achieved significantly more cycles to cut-out failure compared to the standard OG design (p < 0.01), confirming the significantly lower peri-implant bone strain predicted by FE for the EH versus OG groups (p < 0.001). The magnitude of instrumentation inaccuracies was small but had a significant effect on the predicted failure risk (p < 0.01). The sample-specific FE predictions strongly correlated with the experimental results (R2 = 0.70) when incorporating instrumentation inaccuracies. These findings demonstrate the power and validity of FE simulations in improving implant designs towards superior fixation stability of proximal humerus fractures. Computational optimization could be performed involving further implant features and help decrease failure rates. The results underline the importance of accurate surgical execution of implant fixations and the need for high consistency in validation studies.

Percutaneous fixation of intraarticular joint-depression calcaneal fractures with different screw configurations - a biomechanical human cadaveric analysis.

PURPOSE: The aim of this study was to assess the biomechanical performance of different screw configurations for fixation of Sanders type II B joint-depression calcaneal fractures. METHODS: Fifteen human cadaveric lower limbs were amputated and Sanders II B fractures were simulated. The specimens were randomized to three groups for fixation with different screw configurations. The calcanei in Group 1 were treated with two parallel longitudinal screws, entering superiorly the Achilles tendon insertion, and two screws fixing the intraarticular posterior facet fracture line. In Group 2 two screws entered the tuberosity inferiorly to the Achilles tendon insertion and two transverse screws fixed the posterior facet. In Group 3 two screws were inserted along the bone axis, one transverse screw fixed the posterior facet and one oblique screw was inserted from the posteroplantar part of the tuberosity supporting the posterolateral part of the posterior facet. All specimens were biomechanically tested to failure under progressively increasing cyclic loading. RESULTS: Initial stiffness did not differ significantly between the groups, P = 0.152. Cycles to 2 mm plantar movement were significantly higher in both Group 1 (15,847 ± 5250) and Group 3 (13,323 ± 4363) compared with Group 2 (4875 ± 3480), P ≤ 0.048. No intraarticular displacement was observed in any group during testing. CONCLUSIONS: From a biomechanical perspective, posterior facet support by means of buttress or superiorly inserted longitudinal screws results in less plantar movement between the calcaneal tuberosity and the anterior fragments. Inferiorly inserted longitudinal screws are associated with bigger interfragmentary movements.

Advanced CT visualization improves the accuracy of orthopaedic trauma surgeons and residents in classifying proximal humeral fractures: a feasibility study.

PURPOSE: Osteosynthesis of proximal humeral fractures remains challenging with high reported failure rates. Understanding the fracture type is mandatory in surgical treatment to achieve an optimal anatomical reduction. Therefore, a better classification ability resulting in improved understanding of the fracture pattern is important for preoperative planning. The purpose was to investigate the feasibility and added value of advanced visualization of segmented 3D computed tomography (CT) images in fracture classification. METHODS: Seventeen patients treated with either plate-screw-osteosynthesis or shoulder hemi-prosthesis between 2015 and 2019 were included. All preoperative CT scans were segmented to indicate every fracture fragment in a different color. Classification ability was tested in 21 orthopaedic residents and 12 shoulder surgeons. Both groups were asked to classify fractures using three different modalities (standard CT scan, 3D reconstruction model, and 3D segmented model) into three different classification systems (Neer, AO/OTA and LEGO). RESULTS: All participants were able to classify the fractures more accurately into all three classification systems after evaluating the segmented three-dimensional (3D) models compared to both 2D slice-wise evaluation and 3D reconstruction model. This finding was significant (p < 0.005) with an average success rate of 94%. The participants experienced significantly more difficulties classifying fractures according to the LEGO system than the other two classifications. CONCLUSION: Segmentation of CT scans added value to the proximal humeral fracture classification, since orthopaedic surgeons were able to classify fractures significantly better into the AO/OTA, Neer, and LEGO classification systems compared to both standard 2D slice-wise evaluation and 3D reconstruction model.

Proximal humeral fracture osteosynthesis in Belgium: a retrospective population-based epidemiologic study.

PURPOSE: Proximal humeral fractures (PHF) comprise approximately five percent of all fractures and this percentage will continue to increase due to the aging population with accompanying osteoporosis. Most PHF can be treated conservatively; however, in displaced fractures, surgical treatment is recommended. Retrospective analyses of large groups or even populations are important as they can contribute to the needs of the community. The aim of this study was to assess the epidemiology and management of PHF fixation in Belgium based on the most recently available data from the last 5 years. METHODS: The governmental organization National Institute of Health and Disability Insurance provided a population-based database with all PHF treated surgically or nonoperatively. This database was retrospectively assessed. The data included age, sex, region of residence, year and treatment strategy for every patient. Healthcare expenses were also provided. RESULTS: A total of 62,290 PHF were identified in Belgium between 2014 and 2018. The incidence was 111 per 100,000 persons/year. The highest incidence was observed in females and people older than 80 years. The average proportion of osteosynthesis was calculated at 21%. The Belgian government spent on average more than two million euros each year on PHF treatment. CONCLUSION: The overall incidence of PHF increased by 12% over the last 5 years. The majority were treated nonoperatively in Belgium.

One size may not fit all: patient-specific computational optimization of locking plates for improved proximal humerus fracture fixation.

BACKGROUND: Optimal treatment options for proximal humerus fractures (PHFs) are still debated because of persisting high fixation failure rates experienced with locking plates. Optimization of the implants and development of patient-specific designs may help improve the primary fixation stability of PHFs and reduce the rate of mechanical failures. Optimizing the screw orientations in locking plates has shown promising results; however, the potential benefit of subject-specific designs has not been explored yet. The purpose of this study was to evaluate by means of finite element (FE) analyses whether subject-specific optimization of the screw orientations in a fixed-angle locking plate can reduce the predicted cutout failure risk in unstable 3-part fractures. METHODS: FE models of 19 low-density proximal humeri were generated from high-resolution computed tomographic images using a previously developed and validated computational osteosynthesis framework. The specimens were virtually osteotomized to simulate unstable malreduced 3-part fractures and fixed with the PHILOS plates using 6 proximal locking screws. The average principal compressive strain in cylindrical bone regions around the screw tips-a biomechanically validated surrogate for the risk of cyclic screw cutout failure-was defined as the main outcome measure. The angles of the 6 proximal locking screws were optimized via parametric analysis for each humerus individually, resulting in subject-specific screw orientations (SSO). The average peri-implant strains of the SSO were statistically compared with the previously reported cohort-specific (CSO) and original PHILOS screw orientations (PSO) for females vs. males. RESULTS: The optimized SSO significantly reduced the peri-screw bone strain vs. CSO (6.8% ± 4.0%, P = .006) and PSO (25.24% ± 7.93%, P < .001), indicating lower cutout risk for subject-specific configurations. The benefits of SSO vs. PSO were significantly higher for women than men. CONCLUSION: The findings of this study suggest that subject-specific optimization of the locking screw orientations could lead to lower cutout risk and improved PHF fixation. These computer simulation results require biomechanical and clinical corroboration. Further studies are needed to evaluate whether the potential benefit in stability could justify the increased efforts related to implementation of individualized implants. Nevertheless, computational exploration of the biomechanical factors influencing the outcome of fracture fixations could help better understand the fixation failures and reduce their incidence.

Angular stable locking in a novel intramedullary nail improves construct stability in a distal tibia fracture model.

INTRODUCTION: Intramedullary nails are frequently used for treatment of unstable distal tibia fractures. However, insufficient fixation of the distal fragment could result in delayed healing, malunion or nonunion. Recently, a novel concept for angular stable nailing was developed that maintains the principle of relative stability and introduces improvements expected to reduce nail toggling, screw migration and secondary loss of reduction. The aim of this study was to investigate the biomechanical competence of the novel angular stable intramedullary nail concept for treatment of unstable distal tibia fractures, compared to a conventional nail locking in a human cadaveric model under dynamic loading. MATERIALS AND METHODS: Ten pairs of fresh-frozen human cadaveric tibiae with a simulated AO/OTA 42-A3.1 fracture were assigned to 2 groups for reamed intramedullary nailing using either a conventional (non-angular stable) Expert Tibia Nail (ETN) with 3 distal screws or the novel Tibia Nail Advanced (TNA) system with 2 distal angular stable locking low-profile retaining screws. The specimens were biomechanically tested under conditions including initial quasi-static loading, followed by progressively increasing combined cyclic axial and torsional loading in internal rotation until failure of the bone-implant construct. Both tests were monitored by means of motion tracking. RESULTS: Initial nail toggling of the distal tibia fragment in varus and flexion under axial loading was lower for TNA compared to ETN, being significant in flexion, P = 0.91 and P = 0.03. After 5000 cycles, interfragmentary movements in terms of varus, flexion, internal rotation, axial displacement, and shear displacement at the fracture site were all lower for TNA compared to ETN, with flexion and shear displacement being significant, P = 0.14, P = 0.04, P = 0.25, P = 0.11 and P = 0.04, respectively. Cycles to failure until both interfragmentary 5° varus and 5° flexion were significantly higher for TNA compared to ETN, P = 0.04. CONCLUSION: From a biomechanical perspective, the novel angular stable intramedullary nail concept provides increased construct stability and maintains it over time while reducing the number of required locking screws without impeding the flexibility of the nail itself and resists better towards loss of reduction under dynamic loading, compared to conventional locking in intramedullary nailed unstable distal tibia fractures.

A case of an atraumatic implant failure after primary rotating-hinge total knee arthroplasty.

Rotating-hinge knee implants are fully constrained knee prostheses commonly used for revision total knee arthroplasty. Nevertheless, rotating-hinge devices have been increasingly utilized in primary setting. Complications are inevitable in orthopedic surgery, however, implant breakage after RHK arthroplasty has been rarely described in medical literature. We present a rare case of 70-year-old Caucasian, male patient who suffered an atraumatic femoral stem breakage in a primary NexGen ® Rotating Hinge Knee (Zimmer-Biomet ® , Warsaw, IN, USA).

Patient-reported outcomes after primary rotating hinge total knee arthroplasty: a multi-centre clinical cohort study.

PURPOSE: Rotating hinge prostheses for total knee arthroplasty (TKA) are mostly used in revision setting; however, evidence on the use of these constrained devices in primary setting is scarce and inconsistent. Therefore, we aimed to evaluate the functional outcomes after third-generation rotating hinge implants in primary TKA with a minimal follow-up of two years in a large dual-centre observational retrospective clinical trial. METHODS: The hospital databases of two centres were searched for primary rotating hinge arthroplasty from January 2007 to January 2015. A minimum follow-up of at least two years was assured. Patients meeting the inclusion criteria were asked to fill out two self-reported functional scores, the Oxford Knee Score (OKS) and Forgotten Joint Score (FJS), to measure the functional status of the knee. RESULTS: In total, 267 primary rotating hinge knee arthroplasties in 242 patients were performed in two centres. The three major indications were axial malalignment (valgus/varus > 15°), 87/267 (33%), persistent ligamentous instability (28%) and neuromuscular disorders (12%). 184 patients with 202 primary rotating hinge knee arthroplasties could be included that provided data of the self-reported outcome measures (OKS and FJS). A mean OKS score of 37.71 (± 9.23) and a mean FJS score of 63.65 (± 31.01) could be obtained. CONCLUSION: This large clinical study suggests that constrained devices provide the best results when treating bone-on-bone tricompartimental osteoarthritis of the knee with severe axial deviation (valgus/varus > 15°) and/or persistent ligamentous instability.

Osteosynthesis of proximal humeral fractures: a 1-year analysis of failure in a Belgian level-1 trauma centre.

PURPOSE: Proximal humeral fractures are the third most common fractures affecting the elderly. Angular stable osteosynthesis has become indispensable in the operative treatment. However, surgical fixation remains challenging. The aim of this retrospective study was to analyse the failure rate after osteosynthesis of proximal humeral fractures over a year in a level-1 trauma centre. Furthermore, parameters that are presumed to be related to osteosynthesis failure will be investigated and discussed. METHODS: After meeting the exclusion criteria, 134 patients were operatively treated with angular stable osteosynthesis between January 2017 and January 2018 at the University Hospitals of Leuven. RESULTS: Circa 16% of the proximal humeral osteosyntheses failed. Our study showed that the most significant parameter for osteosynthesis failure was smoking. The odds of failure were significantly lower if treated by a shoulder surgeon compared to another trauma surgeon in the plate and nail group combined. CONCLUSION: The management of proximal humeral fracture osteosynthesis remains a controversial subject. In this retrospective analysis, a failure rate of 15.7% was calculated. Smoking is a statistically significant parameter related to osteosynthesis failure. The subspecialty of the treating trauma surgeon affected the failure rate significantly. A lower failure rate was noted after osteosynthesis by a shoulder surgeon compared to another trauma surgeon.

Evaluation of screw placement in proximal humerus fractures regarding drilling manoeuvre and surgeon's experience.

INTRODUCTION: Following proximal humeral plate osteosynthesis, mechanical complication rates ranging up to 40% have been reported. The study aims to determine the influence of surgeons' experience and the technique of drilling on the complication rate. MATERIALS AND METHODS: The sample involved 45 cadaveric humeri. Six orthopaedic surgeons were divided into two groups with regard to their level of experience (novice versus expert group). On each humerus two different proximal humerus plates were applied. Drillings were performed either with a sharp or worn drill bit (to simulate either sharp or blunt drilling). The respective holes were drilled until the respective participant thought to have placed the drill bit subchondrally, followed by perforation of the cartilage of the humeral head. Both these values and cases of unintended penetration of the articular cavity were evaluated. RESULTS: Fourteen holes (3.6%) were primary penetrated in the joint cavity in the worn-drill-bit-subgroup and 19 holes (5%) in the sharp-drill-bit-group. The latter had an average distance between the chosen subchondral position and the humeral articular surface of 8.3 mm and the worn-drill-bit-subgroup was at 10.6 mm. In the novice group 20 perforations (5.2%) of the joint space occurred and the mean interval between the chosen subchondral point and the humeral articular surface was 4.0 mm. The experienced surgeons showed a perforation rate of 3.4% and were at a mean of 14.9 mm. There were no significant differences regarding drilling manoeuvres and experience. CONCLUSION: Although our results are satisfactory, they can be traced back to the relatively high interval between the respective chosen position of the drill bit and the humeral articular surface which may not guarantee screw stability during ORIF of all fracture patterns.

Screw placement in two different implants for proximal humeral fractures regarding regional differences in bone mineral density: An anatomical study.

BACKGROUND: The aim of this study was to investigate proximal humerus plating regarding drill depth and over penetration of the glenohumeral joint and to find a relation between these findings and different areas of bone mineral density (BMD) in the humeral head. MATERIAL & METHODS: The study sample involved 45 upper extremities from human adult cadavers. Two different plates (HOFER; PHILOS) were applied to the proximal humerus. Each hole was drilled until the respective participant thought to have placed the drill bit subchondral. Next, penetration of the far cortex was conducted to determine the residual bone stock. Additionally, the point of screw penetration of the far cortex was identified for each hole of the plates and allocated to five regions with different bone mineral density as described by Tingart et al. RESULTS: The screw penetration rate and the residual bone stock were compared within the 5 BMD regions. A significantly thicker residual bone stock was found at the central region (SD ± 13.1 mm) than in the anterior region (SD ± 9.5 mm) and in the posterior region (SD ± 8.5 mm). The anterior region revealed a significantly higher penetration rate than the posterior region (p = 0.01) and the central region (p = 0.03). CONCLUSION: The anterior region of the humeral head was associated with a higher over penetration rate of the far cortex into the glenohumeral joint and a decreased bone stock after subchondral drilling representing a reduced bone mineral density (BMD). LEVEL OF EVIDENCE: Cadaver Study.

Comparison of Constrained Acetabular Components and Dual Mobility Cups in Revision Total Hip Arthroplasty: A Literature Review.

Recurrent instability remains a common cause of failure after revision total hip arthroplasty (THA). Dual mobility (DM) cups and designs with constrained acetabular liners (CAL) have both been developed to help overcome this challenge. The aim of this report is to compare safety and efficacy outcomes of both designs based on the literature. A comprehensive literature review including published evidence on the results of DM and CAL in revision THA was performed and summarized. Available literature focusing on overall survival, dislocation, loosening, intra-prosthetic dislocation (IPD), and functional outcomes were analysed. Forty-six reports including an evaluation of 5,617 total hips were evaluated were included in the review. The included studies were divided into two distinct groups based on implantation approach: i) CAL (n=15) and ii) DM (n=31). The DM group had higher overall survival rates (94.7% vs. 81.0%), lower dislocation rates (2.6% vs. 11.0%), and lower acetabular loosening rates (1.0% vs. 2.0%) compared to the CAL group. IPDs were reported in 6 studies (mean rate, 0.6%). No differences in functional outcomes were identified due to incomplete reports. Our observations reveal that designs with CAL have poorer outcomes as compared to DM cups in revision THA. Currently, the use of DM seems more appropriate since they offer lower rates of dislocations, loosening and re-revisions in the short- and mid-term. Concerns regarding the potential of increased wear in a younger, high-demand population require additional data and evaluation by long-term studies for the DM design.

Short-term outcome trapeziectomy with ligament reconstruction and tendon interposition versus trapeziometacarpal prosthesis : a literature review.

Trapeziectomy with ligament reconstruction and tendon interposition and trapeziometacarpal prosthesis are two commonly used procedures for first carpometacarpal joint osteoarthritis. The purpose of this study is to compare the short-term outcome of trapeziectomy with ligament reconstruction and tendon interposition to trapeziometacarpal prosthesis. Pubmed, Cochrane library and science direct database were searched with adequate search terms. Used parameters were force, pain, mobility, functionality and complication. All papers describing short-term outcome of ligament reconstruction and tendon interposition or trapeziometacarpal prosthesis were included in this review. Trapeziometacarpal prostheses showed faster pain relief compared with trapeziectomy and ligament reconstruction and tendon interposition. Overall, there was a better strength in the trapeziometacarpal prosthesis group. A lack of information was found about the short- term functionality. The mobility recovers faster in the prosthesis group, although different scoring scales were used for measurement. We could confirm the faster pain relief in the prosthesis group and generally a faster recovery of strength and mobility. In the prosthesis group were more short-term complications. More studies are required to evaluate the short-term recovery of strength, the mobility, functionality and satisfaction.

Failure after proximal humeral fracture osteosynthesis: a one year analysis of hospital-related healthcare cost.

PURPOSE: The issue of rising healthcare costs and limited resources is a topic of worldwide discussion over the last several decades. We hypothesized that failure of proximal humeral fracture osteosynthesis is presumed to be an important determinant in healthcare resources and related costs. The aim of this study was to calculate the total hospital-related healthcare cost of proximal humeral fracture osteosynthesis over one  year focusing on failure. METHODS: A total of 121 patients with a proximal humeral fracture treated by angular stable osteosynthesis were included in this retrospective study. All hospital-related healthcare costs were investigated. Five main hospital-related cost categories were defined: hospitalization cost, honoraria, day care admission, materials, and pharmaceuticals. RESULTS: A total healthcare cost of € 1,139,448 was calculated for the whole patient group. Twelve patients needed revision surgery due to complications or fixation-related failure. This failure rate alone costed € 190,809 of the healthcare resources. In other words, failure after proximal humeral fracture osteosynthesis costed 17% of the total healthcare expenditure inone year. CONCLUSION: This study demonstrates that a high amount of hospital-related healthcare resources is spent because of failure after proximal humeral fracture osteosynthesis. Further research is necessary and should investigate on how to prevent failure. This is not only in the patient's interest, but it is also of great importance for maintaining a healthy healthcare system.

Axillary nerve elongation in humeral fracture plating: A cadaveric study for comparison between straight and helical Philos plates.

Helical plating is a known concept in humeral fracture treatment. Attention should be paid to the axillary nerve when inserting a plate underneath the deltoid muscle. The purpose of this cadaveric study was to estimate axillary nerve stretching when introducing the plate. METHODS: On 42 fresh frozen human humeri, an 8-, 10- and 12-hole Philos plate in a straight and a helical shape were compared measuring the maximum plate-bone-distance. RESULTS: For all three plate lengths, the helical plates had a significantly lower plate-bone-distance. CONCLUSION: Indirectly, this suggests a lower axillary nerve elongation and hence less chance of nerve damage.