Substantial Variation in Decision Making to Perform Subacromial Decompression Surgery for Subacromial Pain Syndrome Between Orthopaedic Shoulder Surgeons for Identical Clinical Scenarios: A Case-Vignette Study

Purpose

To provide further insight into the variation in decision making to perform subacromial decompression (SAD) surgery in patients with subacromial pain syndrome (SAPS) and its influencing factors.

Methods

Between November 2021 and February 2022, we invited 202 Dutch Shoulder and Elbow Society members to participate in a cross-sectional Web-based survey including 4 clinical scenarios of SAPS patients. Scenarios varied in patient characteristics, clinical presentation, and other contextual factors. For each scenario, respondents were asked (1) to indicate whether they would perform SAD surgery, (2) to indicate the probability of benefit of SAD surgery (i.e., pain reduction), (3) to indicate the probability of harm (i.e., complications), and (4) to rank the 5 most important factors influencing their treatment decision.

Results

A total of 78 respondents (39%) participated. The percentage of respondents who would perform SAD surgery ranged from 4% to 25% among scenarios. The median probability of perceived benefit ranged between 70% and 79% across scenarios for respondents indicating to perform surgery compared with 15% to 29% for those indicating not to perform surgery. The difference in the median probability of perceived harm ranged from 3% to 9% for those indicating to perform surgery compared with 8% to 13% for those indicating not to perform surgery. Surgeons who would perform surgery mainly reported patient-related factors (e.g., complaint duration and response to physical therapy) as the most important factors to perform SAD surgery, whereas surgeons who would not perform surgery mainly reported guideline-related factors.

Conclusions

Overall, Dutch orthopaedic shoulder surgeons are reluctant to perform SAD surgery in SAPS patients. There is substantial variation among orthopaedic surgeons regarding decisions to perform SAD surgery for SAPS even when evaluating identical scenarios, where particularly the perceived benefit of surgery differed between those who would perform surgery and those who would not. Surgeons who would not perform SAD surgery mainly referred to guideline-related factors as influential factors for their decision, whereas those who would perform SAD surgery considered patient-related factors more important.

Clinical Relevance

There is substantial variation in decision making to perform SAD surgery for SAPS between individual orthopaedic surgeons for identical case scenarios.

Continued Stabilization of a Cementless 3D-Printed Total Knee Arthroplasty: Five-Year Results of a Randomized Controlled Trial Using Radiostereometric Analysis

BACKGROUND

Three-dimensional (3D) printing of highly porous orthopaedic implants aims to promote better osseointegration, thus preventing aseptic loosening. However, short-term radiostereometric analysis (RSA) after total knee arthroplasty (TKA) has shown higher initial migration of cementless 3D-printed tibial components compared with their cemented counterparts. Therefore, critical evaluation of longer-term tibial component migration is needed. We investigated migration of a cementless 3D-printed and a cemented tibial component with otherwise similar TKA design during 5 years of follow-up, particularly the progression in migration beyond 2 years postoperatively.

METHODS

Seventy-two patients were randomized to a cementless 3D-printed Triathlon Tritanium (Stryker) cruciate-retaining (CR) TKA or a cemented Triathlon CR (Stryker) TKA implant. Implant migration was evaluated with RSA at baseline and postoperatively at 3 months and at 1, 2, and 5 years. The maximum total point motion (MTPM) of the tibial component was compared between the groups at 5 years, and progression in migration was assessed between 2 and 5 years. Individual implants were classified as continuously migrating if the MTPM was ≥0.1 mm/year beyond 2 years postoperatively. Clinical scores were evaluated, and a linear mixed-effects model was used to analyze repeated measurements.

RESULTS

At 5 years, the mean MTPM was 0.66 mm (95% confidence interval [CI], 0.56 to 0.78 mm) for the cementless group and 0.53 mm (95% CI, 0.43 to 0.64 mm) for the cemented group (p = 0.09). Between 2 and 5 years, there was no progression in mean MTPM for the cementless group (0.02 mm; 95% CI, -0.06 to 0.10 mm) versus 0.07 mm (95% CI, 0.00 to 0.14) for the cemented group. One implant was continuously migrating in the cementless group, and 4 were continuously migrating in the cemented group. The clinical scores were comparable between the groups across the entire time of follow-up.

CONCLUSIONS

No significant difference in mean migration was found at 5 years between the cementless and cemented TKA implants. Progression of tibial component migration was present beyond 2 years for the cemented implant, whereas the cementless implant remained stable after initial early migration.

LEVEL OF EVIDENCE

Therapeutic Level I . See Instructions for Authors for a complete description of levels of evidence.

Impact of Active Disinvestment on Decision-Making for Surgery in Patients With Subacromial Pain Syndrome: A Qualitative Semi-structured Interview Study Among Hospital Sales Managers and Orthopedic Surgeons

BACKGROUND

Withdrawal of reimbursement for low-value care through a policy change, ie, active disinvestment, is considered a potentially effective de-implementation strategy. However, previous studies have shown conflicting results and the mechanism through which active disinvestment may be effective is unclear. This study explored how the active disinvestment initiative regarding subacromial decompression (SAD) surgery for subacromial pain syndrome (SAPS) in the Netherlands influenced clinical decision-making around surgery, including the perspectives of orthopedic surgeons and hospital sales managers.

METHODS

We performed 20 semi-structured interviews from November 2020 to October 2021 with ten hospital sales managers and ten orthopedic surgeons from twelve hospitals across the Netherlands as relevant stakeholders in the active disinvestment process. The interviews were video-recorded and transcribed verbatim. Inductive thematic analysis was used to analyse interview transcripts independently by two authors and discrepancies were resolved through discussion.

RESULTS

Two overarching themes were identified that negatively influenced the effect of the active disinvestment initiative for SAPS. The first theme was that the active disinvestment represented a "Too small piece of the pie" indicating little financial consequences for the hospital as it was merely used in negotiations with healthcare insurers to reduce costs, required a disproportionate amount of effort from hospital staff given the small saving-potential, and was not clearly defined nor enforced in the overall healthcare insurer agreements. The second theme was "They [healthcare insurer] got it wrong," as the evidence and guidelines had been incorrectly interpreted, the active disinvestment was at odds with clinician experiences and beliefs and was perceived as a reduction in their professional autonomy.

CONCLUSION

The two overarching themes and their underlying factors highlight the complexity for active disinvestment initiatives to be effective. Future de-implementation initiatives including active disinvestment should engage relevant stakeholders at an early stage to incorporate their different perspectives, gain support and increase the probability of success.

Quality and Utility of European Cardiovascular and Orthopaedic Registries for the Regulatory Evaluation of Medical Device Safety and Performance Across the Implant Lifecycle: A Systematic Review

BACKGROUND

The European Union Medical Device Regulation (MDR) requires manufacturers to undertake post-market clinical follow-up (PMCF) to assess the safety and performance of their devices following approval and Conformité Européenne (CE) marking. The quality and reliability of device registries for this Regulation have not been reported. As part of the Coordinating Research and Evidence for Medical Devices (CORE-MD) project, we identified and reviewed European cardiovascular and orthopaedic registries to assess their structures, methods, and suitability as data sources for regulatory purposes.

METHODS

Regional, national and multi-country European cardiovascular (coronary stents and valve repair/replacement) and orthopaedic (hip/knee prostheses) registries were identified using a systematic literature search. Annual reports, peer-reviewed publications, and websites were reviewed to extract publicly available information for 33 items related to structure and methodology in six domains and also for reported outcomes.

RESULTS

Of the 20 cardiovascular and 26 orthopaedic registries fulfilling eligibility criteria, a median of 33% (IQR: 14%-71%) items for cardiovascular and 60% (IQR: 28%-100%) items for orthopaedic registries were reported, with large variation across domains. For instance, no cardiovascular and 16 (62%) orthopaedic registries reported patient/ procedure-level completeness. No cardiovascular and 5 (19%) orthopaedic registries reported outlier performances of devices, but each with a different outlier definition. There was large heterogeneity in reporting on items, outcomes, definitions of outcomes, and follow-up durations.

CONCLUSION

European cardiovascular and orthopaedic device registries could improve their potential as data sources for regulatory purposes by reaching consensus on standardised reporting of structural and methodological characteristics to judge the quality of the evidence as well as outcomes.

Antimicrobial activity of ion-substituted calcium phosphates: A systematic review

In this systematic review, the antimicrobial effect of ion-substituted calcium phosphate biomaterials was quantitatively assessed. The literature was systematically searched up to the 6th of December 2021. Study selection and data extraction was performed in duplo by two independent reviewers with a modified version of the OHAT tool for risk of bias assessment. Any differences were resolved by consensus or by a referee. A mixed effects model was used to investigate the relation between the degree of ionic substitution and bacterial reduction. Of 1016 identified studies, 108 were included in the analysis. The methodological quality of included studies ranged from 6 to 16 out of 18 (average 11.4). Selenite, copper, zinc, rubidium, gadolinium, silver and samarium had a clear antimicrobial effect, with a log reduction in bacteria count of 0.23, 1.8, 2.1, 3.6, 5.8, 7.4 and 10 per atomic% of substitution, respectively. There was considerable between-study variation, which could partially be explained by differences in material formulation, study quality and microbial strain. Future research should focus on clinically relevant scenarios in vitro and the translation to in vivo prevention of PJI.

A Novel Treatment for Anterior Shoulder Instability: A Biomechanical Comparison Between a Patient-Specific Implant and the Latarjet Procedure

BACKGROUND

Anterior glenohumeral instability with >20% glenoid bone loss is a disorder that can be treated with the Latarjet stabilizing procedure; however, complications are common. The purposes of this study were to (1) evaluate the effect of an anatomic-specific titanium implant produced by 3-dimensional (3D) printing as a treatment option for recurrent shoulder instability with substantial glenoid bone loss and (2) compare the use of that implant with the Latarjet procedure.

METHODS

Ten fresh-frozen cadaveric shoulders (mean age at the time of death, 78 years) were tested in a biomechanical setup with the humerus in 30° of abduction and in neutral rotation. The shoulders were tested under 5 different conditions: (1) normal situation, (2) creation of an anterior glenoid defect, (3) implantation of an anatomic-specific titanium implant produced by 3D printing, and the Latarjet procedure (4) with and (5) without 10 N of load attached to the conjoined tendon. In each condition, the humerus was translated 10 mm anteriorly relative to the glenoid, and the maximum peak translational force that was necessary for this translation was measured.

RESULTS

After creation of the glenoid defect, the mean translational peak force decreased by 30% ± 6% compared with that for the normal shoulder. After restoration of the original glenoid anatomy, the translational force needed to dislocate the humeral head from the glenoid significantly increased compared with that in the defect condition-to 119% ± 16% of normal (p < 0.01) with the 3D-printed anatomic-specific implant and to 121% ± 48% of normal (p < 0.01) following the Latarjet procedure. No significant differences in mean translational force were found between the anatomic-specific implant and the Latarjet procedure (p = 0.72).

CONCLUSIONS

The mean translational peak force needed to dislocate the humerus 10 mm anteriorly on the glenoid was higher after glenoid restoration with the 3D-printed anatomic-specific implant compared with when the glenoid had a 20% surface defect but also compared with when the glenoid was intact. No differences in mean translational peak force were found between the 3D-printed anatomic-specific glenoid implant and the Latarjet procedure, although there was less variability in the 3D-implant condition.

CLINICAL RELEVANCE

Novel 3D-printing technology could provide a reliable patient-specific alternative to solve problems related to traditional treatment methods for shoulder instability.

Managing persistent wound leakage after total knee and hip arthroplasty. Results of a nationwide survey among Dutch orthopaedic surgeons

Background: Persistent wound leakage after joint arthroplasty is a scantily investigated topic, despite the claimed relation with a higher risk of periprosthetic joint infection. This results in a lack of evidence-based clinical guidelines for the diagnosis and treatment of persistent wound leakage after joint arthroplasty. Without such guideline, clinical practice in orthopaedic hospitals varies widely. In preparation of a nationwide multicenter randomized controlled trial on the optimal treatment of persistent wound leakage, we evaluated current Dutch orthopaedic care for persistent wound leakage after joint arthroplasty. Methods: We conducted a questionnaire-based online survey among all 700 members of the Netherlands Orthopaedic Association, consisting of 23 questions on the definition, classification, diagnosis and treatment of persistent wound leakage after joint arthroplasty. Results: The questionnaire was completed by 127 respondents, representing 68% of the Dutch hospitals that perform orthopaedic surgery. The results showed wide variation in the classification, definition, diagnosis and treatment of persistent wound leakage among Dutch orthopaedic surgeons. 56.7% of the respondents used a protocol for diagnosis and treatment of persistent wound leakage, but only 26.8% utilized the protocol in every patient. Most respondents (59.1%) reported a maximum period of persistent wound leakage before starting non-surgical treatment of 3 to 7 days after index surgery and 44.1% of respondents reported a maximum period of wound leakage of 10 days before converting to surgical treatment. Conclusions: The wide variety in clinical practice underscores the importance of developing an evidence-based clinical guideline for the diagnosis and treatment of persistent wound leakage after joint arthroplasty. To this end, a nationwide multicenter randomized controlled trial will be conducted in the Netherlands, which may provide evidence on this important and poorly understood topic.

Peri-prosthetic tissue cells show osteogenic capacity to differentiate into the osteoblastic lineage

During the process of aseptic loosening of prostheses, particulate wear debris induces a continuous inflammatory-like response resulting in the formation of a layer of fibrous peri-prosthetic tissue at the bone-prosthesis interface. The current treatment for loosening is revision surgery which is associated with a high-morbidity rate, especially in old patients. Therefore, less invasive alternatives are necessary. One approach could be to re-establish osseointegration of the prosthesis by inducing osteoblast differentiation in the peri-prosthetic tissue. Therefore, the aim of this study was to investigate the capacity of peri-prosthetic tissue cells to differentiate into the osteoblast lineage. Cells isolated from peri-prosthetic tissue samples (n = 22)-obtained during revision surgeries-were cultured under normal and several osteogenic culture conditions. Osteogenic differentiation was assessed by measurement of Alkaline Phosphatse (ALP), mineralization of the matrix and expression of several osteogenic genes. Cells cultured in osteogenic medium showed a significant increase in ALP staining (p = 0.024), mineralization of the matrix (p < 0.001) and ALP gene expression (p = 0.014) compared to normal culture medium. Addition of bone morphogenetic proteins (BMPs), a specific GSK3β inhibitor (GIN) or a combination of BMP and GIN to osteogenic medium could not increase ALP staining, mineralization, and ALP gene expression. In one donor, addition of GIN was required to induce mineralization of the matrix. Overall, we observed a high-inter-donor variability in response to osteogenic stimuli. In conclusion, peri-prosthetic tissue cells, cultured under osteogenic conditions, can produce alkaline phosphatase and mineralized matrix, and therefore show characteristics of differentiation into the osteoblastic lineage. © 2016 The Authors. Journal of Orthopaedic Research published by Wiley Periodicals, Inc. on behalf of Orthopaedic Research Society. J Orthop Res 35:1732-1742, 2017.

An in Vivo Simulation of Isometry of the Anterolateral Aspect of the Healthy Knee

BACKGROUND

To assess the isometry of theoretical lateral extra-articular reconstruction (LER), we evaluated theoretical grafts attached to various points on the lateral femoral condylar area and to either Gerdy's tubercle or the anatomic attachment site of the anterolateral ligament to the tibia.

METHODS

In 18 subjects, healthy knees with no history of either injury or surgery involving the lower extremity were studied. The subjects performed a sit-to-stand motion (from approximately 90° of flexion to full extension), and each knee was studied using magnetic resonance and dual fluoroscopic imaging techniques. The 3-dimensional wrapping paths of each theoretical LER graft were measured. Grafts showing the least change in length during the sit-to-stand motion were considered to be the most isometric.

RESULTS

The most isometric attachment site on the lateral femoral epicondyle to either of the studied tibial attachment sites was posterior-distal to the femoral attachment site of the fibular collateral ligament. The LER graft had a mean change in length of approximately 3%. Moving the femoral attachment site anteriorly resulted in increased length of the graft with increasing flexion; more posterior attachment sites resulted in decreased length with increasing flexion. Moving the attachment site in the proximal-distal direction had a less profound effect. Moving the tibial attachment site from Gerdy's tubercle to the tibial attachment site of the anterolateral ligament affected the overall isometric distribution on the lateral femoral epicondyle.

CONCLUSIONS

The most isometric attachment site on the femur for an LER would be posterior-distal to the femoral attachment site of the fibular collateral ligament. Different length changes for LER grafts were identified with respect to different femoral attachment sites. Desirable graft fixation locations for treating anterolateral rotatory instability were found posterior-proximal to the femoral fibular collateral ligament attachment.

CLINICAL RELEVANCE

The present data could be used both in biomechanical studies and in clinical studies as guidelines for planning LER surgical procedures.

Comparison of different pseudotumor grading systems in a single cohort of metal-on-metal hip arthroplasty patients

OBJECTIVE

Follow-up of pseudotumors observed with metal-artefact reducing sequence (MARS)-magnetic resonance imaging (MRI) following metal-on-metal total hip arthroplasty (MoMTHA) depends on how severe these pseudotumors are graded. Several pseudotumor grading systems for MARS-MRI have emerged but little is known of their validity. We studied the intra- and interobserver reliability of three different pseudotumor grading systems in a single cohort of MoMTHA.

PATIENTS AND METHODS

Two experienced musculoskeletal radiologists independently used three different pseudotumor grading systems for classifying MARS-MRI results of the same cohort of 42 MoMTHA patients (49 hips, mean follow-up 5.2 years). Intraobserver and interobserver reliability for each grading system was measured using Cohen's kappa (κ). Variance in pseudotumor severity grading between systems was analyzed.

RESULTS

Intraobserver reliability on grading pseudotumor severity with the Anderson, Matthies, and Hauptfleisch grading system scored 0.47, 0.10, and 0.35 (observer 1), and 0.75, 0.38, and 0.42 (observer 2), respectively. Interobserver reliability scores for pseudotumor severity were 0.58, 0.23, and 0.34, respectively.

CONCLUSIONS

Intraobserver reliability for grading pseudotumor severity on MARS-MRI ranged from poor to good, dependent on observer and grading system used. Interobserver reliability scored best with the Anderson system. A more succinct pseudotumor severity grading system is needed for clinical use.

Minimal clinically important differences in health-related quality of life after total hip or knee replacement: A systematic review

OBJECTIVES

We aimed first to summarise minimal clinically important differences (MCIDs) after total hip (THR) or knee replacement (TKR) in health-related quality of life (HRQoL), measured using the Short-Form 36 (SF-36). Secondly, we aimed to improve the precision of MCID estimates by means of meta-analysis.

METHODS

We conducted a systematic review of English and non-English articles using MEDLINE, the Cochrane Controlled Trials Register (1960-2011), EMBASE (1991-2011), Web of Science, Academic Search Premier and Science Direct. Bibliographies of included studies were searched in order to find additional studies. Search terms included MCID or minimal clinically important change, THR or TKR and Short-Form 36. We included longitudinal studies that estimated MCID of SF-36 after THR or TKR.

RESULTS

THREE STUDIES MET OUR INCLUSION CRITERIA, DESCRIBING A DISTINCT STUDY POPULATION: primary THR, primary TKR and revision THR. No synthesis of study results can be given.

CONCLUSIONS

Although we found MCIDs in HRQoL after THR or TKR have limited precision and are not validated using external criteria, these are still the best known estimates of MCIDs in HRQoL after THR and TKR to date. We therefore advise these MCIDs to be used as absolute thresholds, but with caution.

Validity of joint space width measurements in hand osteoarthritis

OBJECTIVE

To investigate the validity of joint space width (JSW) measurements in millimeters (mm) in hand osteoarthritis (OA) patients by comparison to controls, grading of joint space narrowing (JSN), and clinical features.

METHODS

Hand radiographs of 235 hand OA patients (mean age 65 years, 83% women) and 471 controls were used. JSW was measured with semi-automated image analysis software in the distal, proximal interphalangeal and metacarpal joints (DIPJs, PIPJs and MCPJs). JSN (grade 0-3) was assessed using the osteoarthritis research society international (OARSI) atlas. Associations between the two methods and clinical determinants (presence of pain, nodes and/or erosions, decreased mobility) were assessed using Generalized Estimating Equations with adjustments for age, sex, body mass index (BMI) and mean width of proximal phalanx.

RESULTS

JSW was measured in 5631 joints with a mean JSW of 0.98 mm (standard deviation (SD) 0.21), being the smallest for DIPJs (0.70 (SD 0.25)) and largest for MCPJs (1.40 (SD 0.25)). The JSN=0 group had a mean JSW of 1.28 mm (SD 0.34), the JSN=3 group 0.17 mm (SD 0.23). Controls had larger JSW than hand OA patients (P-value<0.001). In hand OA, females had smaller JSW than men (β -0.08, (95% confidence interval (95% CI) -0.15 to -0.01)) and lower JSW was associated with the presence of pain, nodes, erosions and decreased mobility (adjusted β -0.21 (95% CI -0.27, -0.16), -0.37 (-0.40, -0.34), -0.61 (-0.68, -0.54) and -0.46 (-0.68, -0.24) respectively). These associations were similar for JSN in grades.

CONCLUSION

In hand OA the quantitative JSW measurement is a valid method to measure joint space and shows a good relation with clinical features.

[Thrombosis prevention in orthopaedic surgery: clinical practice in the Netherlands in 2002]

OBJECTIVE

Establish the use of thromboprophylaxis in orthopaedic surgery both during and after the hospital admission.

DESIGN

Cross-sectional study.

METHOD

In April 2002, a letter was sent to all orthopaedic surgeons in the Netherlands announcing that at every hospital with a Department of Orthopaedic Surgery, an orthopaedic surgeon would be approached for a telephone survey. They were phoned in the months April-June 2002. This study included hospitals where major orthopaedic surgery (e.g. the insertion of hip or knee prostheses and hip fracture surgery) took place (n = 124) as well as clinics that only performed day treatments (n = 5).

RESULTS

For major orthopaedic operations, 91% of the hospitals used low molecular weight heparin (LMWH) during the admission period: 36% as monotherapy and 55% in combination with coumarin derivates. In 85% of cases the use of LMWH was started preoperatively. Coumarin derivates were used as a monotherapy in 9% of the hospitals. In 37% of the hospitals the use of NSAIDs was continued, particularly in patients with rheumatoid arthritis. In 94% of the hospitals, the use of acetylsalicylic acid was always stopped. In 97% of the hospitals prophylaxis was given after discharge in the form of LMWH (37% of the cases) or coumarin derivates (63% of the cases). The use of thromboprophylaxis with respect to arthroscopies and plaster immobilisation was variable.

[Brachial plexus injury due to unhealed or wrongly healed clavicular fracture]

Two men, aged 65 and 27 years, had persistent dysesthesia of digits IV and V 18 and 8 months, respectively, after conservative treatment of dislocated comminuted clavicular fractures. In both patients, the fracture was found to have healed poorly. There was pseudoarthrosis, shortening and malrotation. Following surgical decompression of the neurogenic structures by elongation and internal fixation of the clavicle, motor and sensory functions recovered completely. The incidence of clavicular fractures is high, but complications are rare. Symptom recognition and timely treatment can prevent irreversible nerve damage.

Retain or sacrifice the posterior cruciate ligament in total knee arthroplasty? A histopathological study of the cruciate ligament in osteoarthritic and rheumatoid disease

BACKGROUND

The decision whether to retain or resect the posterior cruciate ligament in total knee arthroplasty is at present determined clinically by preoperative radiological variables focusing upon the amount of joint destruction, and subsequent soft tissue contractures. However, these variables give only indirect information on the histological integrity and proprioceptive properties of the posterior cruciate ligament.

METHODS

Twenty posterior cruciate ligaments, obtained during total knee arthroplasty, were evaluated histologically to study the relation between the degree of preoperative radiological joint destruction, structural integrity of the posterior cruciate ligament and the neurological integrity of the targeted tissue. Eleven patients had osteoarthritis and nine patients rheumatoid arthritis. Haematoxylin and eosin, Alcian blue (mucoid degeneration), elastica von Gieson, Gomori (elastic fibres and collagen), and immunohistochemical staining for neural structures were used.

RESULTS

In all but one of the posterior cruciate ligaments, morphologically intact neural tissue was present in the peritendineum of the ligaments. Structural integrity of the collagen framework was present in only seven posterior cruciate ligaments. These cases all had grade three or four radiological joint destruction. In 13 of the specimens a certain degree of mucoid degeneration of collagen was present. All patients with grade five radiological knee joint destruction displayed mucoid degeneration and irregularity of the posterior cruciate ligament fibres.

CONCLUSION

Because of the extensive architectural and probably functional damage of the posterior cruciate ligament in patients who have grade five radiological knee joint destruction, retention of the posterior cruciate ligament in knee prosthesis should not be advocated.

Observations at the articular surface of hip prostheses: an analytical electron microscopy study on wear and corrosion

We used scanning electron microscopy in combination with X-ray microanalysis to evaluate Co-, Cr-, and Mo-based human femoral hip prostheses. In total, 23 retrieved implants and four new implants were included in this study. Scanning electron microscopy of the polished surface of all arthroplasties showed, in addition to the polishing marks, small round and angular holes or pits. Other types of surface irregularities were interpreted as wear or corrosion of the metal compound. In all cases studied, corrosion propagated from holes at the surface of the polished prosthesis heads, in some cases also along phase boundaries. X-ray microanalysis of the intact prosthetic surface showed a relative composition of the elements Co, Cr, and Mo, which was in agreement with the manufacturer's information (63:33:4%). However, X-ray microanalysis spot analysis of the surface holes showed deviation in the relative composition of the elements Co, Cr, and Mo and also the presence of Si, Ti, and Al. Furthermore, Ti and Al could be traced back at an artificially made fracture plane of a new prosthesis. Therefore, Ti and Al have to be present during the manufacturing process. These impurities in the metal prosthesis alloy may create a galvanic element with the Co, Cr, Mo alloy of the implant. If this is the case, such a galvanic element in combination with the electrolyte environment formed by body fluids, can induce galvanic corrosion with release of metal particles.

Digital automated RSA compared to manually operated RSA

The accuracy of digital Roentgen stereophotogrammetric analysis (RSA) was compared to the accuracy of a manually operated RSA system. For this purpose, we used radiographs of a phantom and radiographs of patients. The radiographs of the patients consisted of double examinations of 12 patients that had a tibial osteotomy and of double examinations of 12 patients that received a total hip prosthesis. First, the radiographs were measured manually with an accurate measurement table. Subsequently, the images were digitized by a film scanner at 150 DPI and 300 DPI resolutions and analyzed with the RSA-CMS software. In the phantom experiment, the manually operated system produced significantly better results than the digital system, although the maximum difference between the median values of the manually operated system and the digital system was as low as 0.013mm for translations and 0.033 degrees for rotations. In the radiographs of the patients, the manually operated system and the digital system produced equally accurate results: no significant differences in translations and rotations were found. We conclude that digital RSA is an accurate, fast, and user friendly alternative for manually operated RSA. Currently, digital RSA systems are being used in a growing number of clinical RSA-studies.

The effect of hydroxyapatite on the micromotion of total knee prostheses. A prospective, randomized, double-blind study

A prospective, randomized, double-blind study was performed to evaluate three different means of fixing tibial components during total knee arthroplasty. Eleven components fixed with cement, ten hydroxyapatite-coated components fixed without cement, and ten noncoated components fixed without cement were studied. A posterior cruciate ligament-retaining total condylar implant was used. Micromotion of the components was assessed with roentgen stereophotogrammetric analysis during the two-year follow-up period. There were no significant differences among the patients with regard to age (mean [and standard deviation], 68 +/- 11.6 years), body-mass index (mean, 23 +/- 2.8 kilograms per square meter), or stage of osteoarthrosis (mean, 4 +/- 2.4 according to the classification system of Ahlback and 5 +/- 0.6 according to that of Larsen et al.). The diagnosis was osteoarthrosis in five knees, and it was rheumatoid arthritis in twenty-six. The clinical scores were similar among the study groups. According to the system of the Knee Society, the mean preoperative functional score was 10 +/- 2.9 points and the mean preoperative knee score was 24 +/- 3.2 points. At the two-year follow-up evaluation, these scores were 41 +/- 8.3 and 79 +/- 3.2 points, respectively. A significant difference with regard to micromotion was found between the noncoated components fixed without cement and the hydroxyapatite-coated components fixed without cement as well as between the noncoated components fixed without cement and the components fixed with cement (p < 0.001, analysis of variance). The hydroxyapatite-coated components fixed without cement and the components fixed with cement both had far less micromotion along the longitudinal axis (subsidence) throughout the follow-up period than did the noncoated components fixed without cement. At the two-year follow-up evaluation, the subsidence of the noncoated components was -0.73 +/- 0.924 millimeter, the subsidence of the cemented components was -0.05 +/- 0.109 millimeter, and the subsidence of the hydroxyapatite-coated components was -0.06 +/- 0.169 millimeter. The cemented components as well as the hydroxyapatite-coated components also had less translation along the transverse axis (p < 0.001, analysis of variance) and the sagittal axis (p < 0.001, analysis of variance) compared with the noncoated components. In conclusion, micromotion of hydroxyapatite-coated tibial components fixed without cement was similar to that of tibial components fixed with cement. Therefore, hydroxyapatite, a biological mediator, may be necessary for the adequate fixation of tibial components when cement is not used.

Posterior labrocapsular periosteal sleeve avulsion complicating locked posterior shoulder dislocation

This case presents the imaging features of a posterior shoulder dislocation complicated by a rare but surgically relevant lesion of the posterior labrum. Due to the attachment of the posterior capsule to the posterior portion of the labrum, which in itself is attached to the posterior scapular periosteum, stripping of the labrum by the posterior capsule resulted in a posterior labrocapsular periosteal sleeve avulsion.

[One hundred years of orthopedics in the Netherlands. VI. Surgical treatment of rheumatoid arthritis]

The prevalence of rheumatoid arthritis is about 1%. Loss of independence during daily activities is closely related to the multiple joint involvement of these patients. Also, chronic systemic autoimmune diseases and the extra-articular lesions cause considerable comorbidity. Goal of medical treatment is to reduce disease activity and local joint destruction. The surgical treatment consists of joint protective surgery and joint reconstructive surgery. The former procedure inhibits rapid progression of joint destruction by eradicating the bulk of synovial tissue. The latter procedure compensates for functional loss of an extremity by arthroplasties (both endoprostheses and arthrodeses) to increase the patient's independence. The perfect long-lasting functional prosthesis is available for some joints (hip and knee), but still in development for other joints (e.g. finger joints). In case of surgical reconstruction, a plan for possible complications (e.g. loosening) and their functional implications for the specific patient, should be part of the surgical indication policy. The outcome after a surgical procedure is closely related to preoperative patient factors (e.g. joint destruction) and the surgical expertise. Co-ordination of the treatment plan has to be done by the rheumatologist in close conjunction with the orthopedic/rheuma surgeon.

Roentgen stereophotogrammetric analysis of metal-backed hemispherical cups without attached markers

A method for the detection of micromotion of a metal-backed hemispherical acetabular cup is presented and tested. Unlike in conventional roentgen stereophotogrammetric analysis, the cup does not have to be marked with tantalum markers; the micromotion is calculated from the contours of the hemispherical part and the base circle of the cup. In this way, two rotations (tilt and anteversion) and the translations along the three cardinal axes are obtained. In a phantom study, the maximum error in the position of the cup's centre was 0.04 mm. The mean error in the orientation of the cup was 0.41 degree, with a 95% confidence interval of 0.28-0.54 degree. The in vivo accuracy was tested by repeated measurement of 21 radiographs from seven patients. The upper bound of the 95% tolerance interval for the translations along the transversal, longitudinal, and sagittal axes was 0.09, 0.07, and 0.34 mm, respectively: for the rotation, this upper bound was 0.39 degree. These results show that the new method, in which the position and orientation of metal-backed hemispherical cup is calculated from its projected contours, is a simple and accurate alternative to attaching markers to the cup.

Cemented collarless (Exeter-CPT) versus cementless collarless (PCA) femoral components. A 2- to 14-year follow-up evaluation

The purpose of this study was to compare the intermediate results of total hp arthroplasty with a cemented, collarless, femoral prosthesis design (Exeter, Howmedica, Middlesex, UK and CPT, Zimmer, Warsaw, IN) with those of a cementless, collarless, porous-coated femoral component (PCA, Howmedica). A total of 151 hips in 128 patients were reviewed. In the cemented group, 85 Exeter-CPT prostheses were used in 71 patients with an average follow-up period of 6.5 years. In the uncemented group, 66 PCA prostheses were placed in 57 patients with an average follow-up period of 7 years. Harrington hip scores improved from 50.1 to 80.7 for the PCA group and from 49.5 to 87.3 for the Exeter-CPT group. The patient satisfaction rates were 89 and 96%, respectively. Sixty-eight patients with Exeter or CPT prostheses had excellent function and no significant thigh pain after 2 years. One Exeter stem was revised 10 years after the primary surgery because of aseptic osteolysis due to cement defect. Two Exeter sockets were revised because of aseptic loosening. In the PCA group, the incidence of thigh pain that persisted beyond 2 years was 39.4%, and there were high incidences of distal cortical hypertrophy (66.6%) and bead loosening (45.5%). Sixteen hips were revised for aseptic stem loosening of the socket. The cementless ingrowth stems failed earlier (around 5 years), whereas the cemented stems continued to perform well past 14 years. In this study, the cemented, collarless, tapered, femoral prosthesis gave results superior to those of the uncemented collarless, porous-coated anatomic design at an average follow-up period of 7 years (range, 2-14 years).

The influence of the position of the patellar component on tracking in total knee arthroplasty

The position of the patellar component and patellofemoral symptoms were assessed in a series of 72 cemented polyethylene patellar components in total condylar arthroplasties. A small (25 mm) component was used. The minimum follow up was 2 years and maximum 3 years. A lateral retinacular release was carried out in 22 knees. Clinical results were assessed by questionnaire and 86% had no patellofemoral symptoms. The mean postoperative patellar height was not changed compared to the preoperative height. Lateral placement of the patellar component was associated with both increased medial tilt and lateral subluxation. The component should be inserted so that its centre is slightly medial to the centre of the bone.

Revision hip arthroplasty with the use of cement and impaction grafting. Histological analysis of four cases

The findings of radiographic studies have suggested that the cementing of an implant with a polished tapered stem into a bed of impacted bone allograft may provide adequate function of the joint and may restore bone in the proximal part of the femur. However, radiographs of hips with cancellous bone graft adjacent to cement are difficult to interpret, and the viability of impacted bone graft that is adjacent to cement and its capability for remodeling are unclear. To evaluate this interface further, we obtained biopsy specimens from the proximal part of the femur at the time of removal of trochanteric wires from four patients eleven to twenty-seven months after revision hip arthroplasty with cement and impaction grafting. Three relatively ill defined zones were identified histologically: an inner zone consisting of bone cement, fibrous tissue, and partially necrotic trabeculae with evidence of bone-remodeling; a middle zone consisting of viable trabecular bone and probable formation of so-called neocortex with fewer particles of bone cement; and an outer zone consisting of viable cortex. Fibrous tissue was present around some of the incorporating fragments of bone graft, but no continuous fibrous membrane was seen. Particles of cement were identified, but no polyethylene debris was visible on examination with light microscopy. The results demonstrated remodeling of bone and at least partial restoration of bone stock in the proximal part of the femur after revision arthroplasty with cement and impaction grafting.

Incomplete rupture of the tendon of triceps brachii. A case report

A 36 year old woman with a history of chronic renal failure secondary to acute glomerulonephritis sustained an injury to the tendon of the triceps brachii in her right arm. Magnetic resonance imaging showed an incomplete rupture of the tendon. The injury was successfully treated conservatively.

[Good 10-year results following cemented total knee arthroplasty]

The results of primary total knee arthroplasty in patients with a follow-up of 4-10 years are presented. The study population consisted of osteoarthritis as well as rheumatoid arthritis patients. Both groups were analyzed separately for postoperative pain reduction at rest and during activity, as well as for improvement of some daily activities (walking distance, stair climbing). Pain reduction at rest and during activity was maintained during the follow-up period of 4-10 years. The walking distance and the ability to climb stairs improved during the first few postoperative years, but declined in the later postoperative years. Survival curve analysis of the total knee arthroplasty showed good results for osteoarthritis as well as rheumatoid arthritis (estimated probability of survival of the prosthesis at 10 years' follow-up was 94%).

Survivorship analysis in total condylar knee arthroplasty. A statistical review

Survivorship analysis, which is often encountered in the medical literature, is used to calculate the probability of a certain event, such as failure of a prosthesis, as a function of the time elapsed since an operation. Possible pitfalls in the use of this method are related to the size of the population of patients and the definition of how the outcome is measured. We studied the outcomes of 204 total knee arthroplasties in 165 patients, using six different end-points, in order to illustrate these problems. Survivorship estimates that are cited without confidence intervals have little clinical value.

Is unified monitoring improving patient care?

We compared our standard method of data presentation in the operating room (i.e., using "front end" equipment) with a newly developed, computerized monitoring system called the data acquisition and display system. These two systems differed in that data presentation using the standard front-end equipment was scattered and poorly structured, whereas data obtained from the newly developed system were unified and integrated. To effect the comparison, we examined the "controllability" (i.e., the precision of control) by the anesthesiologist of hemodynamic variables: arterial systolic, mean, and diastolic pressures, mean pulmonary artery pressure, mean central venous pressure, and heart rate. Controllability was assumed to be an indictor of the quality of anesthesia. All perioperative data were stored every 15 seconds on a floppy disk, and these data were available for analysis. The controllability was quantified by calculating the surface area of the signal of a variable outside a defined control zone; the smaller this surface area, the greater the controllability. A Mann-Whitney-Wilcoxon statistical test was done to test whether the two different data presentation systems would result in different levels of controllability (the first zero hypothesis). A Kruskal-Wallis test was done to examine the "inter-anesthesiologist variability" between the two systems (the second zero hypothesis). Our data showed great variability. Looking for factors that might explain this, we found that if preoperative systolic blood pressure was greater than 160 mm Hg and diastolic pressure was greater than 95 mm Hg, hemodynamic variables fluctuated more widely. We could show no differences in controllability when the two systems were compared overall.(ABSTRACT TRUNCATED AT 250 WORDS)