Early aseptic loosening of the tibial component at the cement-implant interface in total knee arthroplasty: a narrative overview of potentially associated factors.

Total knee arthroplasty (TKA) is a highly effective surgical procedure, but in some patients TKAs fail early due to a variety of underlying factors. About 11% of revision TKAs within one year of primary TKA are the result of aseptic loosening of the tibial component at the cement-implant interface. Literature regarding the most important factors associated with this type of loosening is scarce. The objective is to give an overview of the literature regarding factors associated with aseptic loosening of the tibia component at the cement-implant interface in total knee arthroplasty. A narrative literature review based on publications identified through PubMed and CINAHL databases. Twelve studies were identified, which describe a total of 299 cases of early aseptic loosening of the tibia component at the cement-implant interface. The main associated factors reported were cementa- tion factors. These factors included the use of high viscosity cement (HVC), cement application methods and cement thickness. Other main reported associated factor related to implant design factors, which included component shape and surface roughness. The least frequently reported associated factors related to the patient characteristics of body mass index (BMI). Several factors associated with early aseptic loosening of the tibial component at the cement-implant interface in total knee arthroplasty were identified in this review. The most frequently reported associated factors related to cementation factors and implant design factors. Because the literature in this area is scarce, further research is warranted in an effort to prevent early aseptic loosening in future TKAs.

Low sensitivity of a-defensin (Synovasure) test for intra-operative exclusion of prosthetic joint infection.

Background and purpose - The Synovasure lateral flow test was developed as a rapid test for the detection or exclusion of periprosthetic joint infection (PJI). 3 studies have reported promising results on its diagnostic value in total joint revision surgery. We aimed to assess the sensitivity and specificity of the Synovasure test to exclude infection in patients undergoing revision surgery for suspected early aseptic loosening of a total hip or knee arthroplasty. Patients and methods - In a prospective study design, 37 patients who underwent revision surgery for suspected early aseptic loosening (< 3 years after primary arthroplasty) were included. The Synovasure test was used intraoperatively to confirm the aseptic nature of the loosening and 6 tissue cultures were obtained in all cases. Exclusion criteria were patients with a preoperatively confirmed PJI, acute revisions (< 90 days after primary arthroplasty) and cases with malpositioning, wear, or instability of the prosthesis. Results - 5 of the 37 patients were diagnosed with a PJI based on the intraoperative tissue cultures. In only 1 out of these 5 cases this was confirmed by the intraoperative Synovasure test. No tests were falsely positive. Interpretation - In this case series the Synovasure lateral flow test had a low sensitivity to exclude PJI in patients with suspected aseptic loosening. The role of the Synovasure lateral flow test in the intraoperative exclusion of PJI during revision surgery for suspected early aseptic loosening appears to be more limited than previously indicated.

Are radiologists superior to orthopaedic surgeons in diagnosing instability-related shoulder lesions on magnetic resonance arthrography? A multicenter reproducibility and accuracy study.

BACKGROUND: We compared the diagnostic reproducibility and accuracy of musculoskeletal radiologists with orthopaedic shoulder surgeons in 2 large medical centers in assessing magnetic resonance arthrograms (MRAs) of patients with traumatic anterior shoulder instability. METHODS: Forty-five surgically confirmed MRAs were assessed by 4 radiologists, 4 orthopaedic surgeons, 2 radiologic teams, and 2 orthopaedic teams. During MRA assessment and surgery, the same 7-lesion scoring form was used. κ Coefficients, sensitivity, specificity, and differences in percentage of agreement or correct diagnosis (P < .05, McNemar test) were calculated per lesion and overall per the 7 lesion types. RESULTS: The overall κ between the individual radiologists (κ = 0.51, κ = 0.46) and orthopaedic surgeons (κ = 0.46, κ = 0.41) was moderate. Although the overall percentage of agreement between the radiologists was slightly higher than that between the orthopaedic surgeons in both centers (80.0% vs 77.5% and 75.2% vs 73.7%), there was no significant difference. In each medical center, however, the most experienced orthopaedic surgeon was exceedingly more accurate than both radiologists per the 7 lesion types (81.9% vs 72.4%/74.6% and 76.5% vs 67.3%/73.7%). In 3 of 4 cases, this difference was significant. Overall accuracy improvement through consensus assessment was merely established for the weakest member of each team. CONCLUSION: Experienced orthopaedic surgeons are more accurate than radiologists in assessing traumatic anterior shoulder instability-related lesions on MRA. In case of diagnosis disagreement, these orthopaedic surgeons should base their treatment decision on their own MRA interpretation.

Timing of arthroplasty, what is the influence of nocturnal pain and pain at rest on the outcome?

PURPOSE: The purpose of this study was to investigate whether nocturnal pain and pain at rest preoperatively influence the satisfaction in patients after joint arthroplasty. The second research question is whether subjective outcome (VAS/WOMAC) after hip (THA) or knee arthroplasty (TKA) differs in patients with or without nocturnal pain and pain at rest preoperatively compared to those who do not. METHODS: A consecutive group of 189 TKAs and 189 THAs was evaluated. The influence of pain at rest and nocturnal pain preoperatively on the outcome was evaluated by means of a one-way ANOVA. Outcome measurements used were WOMAC, VAS pain and VAS Satisfaction. RESULTS: The results show that satisfaction at follow up was not influenced by the presence of nocturnal pain or pain at rest preoperatively. The presence of nocturnal pain and pain at rest preoperatively did result in a poorer WOMAC pain score WOMAC physical impairment score and a higher VAS pain at rest and activity after surgery for both THA and TKA. CONCLUSION: The results show that the presence of pain at night and pain at rest in symptomatic osteoarthritic patients results in worse VAS and WOMAC scores, but with similar amounts of satisfaction at follow up.

Similar TKA designs with differences in clinical outcome: a randomized, controlled trial of 77 knees with a mean follow-up of 6 years.

BACKGROUND AND PURPOSE: To try to improve the outcome of our TKAs, we started to use the CKS prosthesis. However, in a retrospective analysis this design tended to give worse results. We therefore conducted a randomized, controlled trial comparing this CKS prosthesis and our standard PFC prosthesis. Because many randomized studies between different TKA concepts generally fail to show superiority of a particular design, we hypothesized that these seemingly similar designs would not lead to any difference in clinical outcome. PATIENTS AND METHODS: 82 patients (90 knees) were randomly allocated to one or other prosthesis, and 39 CKS prostheses and 38 PFC prostheses could be followed for mean 5.6 years. No patients were lost to follow-up. At each follow-up, patients were evaluated clinically and radiographically, and the KSS, WOMAC, VAS patient satisfaction scores and VAS for pain were recorded. RESULTS: With total Knee Society score (KSS) as primary endpoint, there was a difference in favor of the PFC group at final follow-up (p = 0.04). Whereas there was one revision in the PFC group, there were 6 revisions in the CKS group (p = 0.1). The survival analysis with any reoperation as endpoint showed better survival in the PFC group (97% (95% CI: 92-100) for the PFC group vs. 79% (95% CI: 66-92) for the CKS group) (p = 0.02). INTERPRETATION: Our hypothesis that there would be no difference in clinical outcome was rejected in this study. The PFC system showed excellent results that were comparable to those in previous reports. The CKS design had differences that had considerable negative consequences clinically. The relatively poor results have discouraged us from using this design.

Correction accuracy and collateral laxity in open versus closed wedge high tibial osteotomy. A one-year randomised controlled study.

In a randomised clinical trial in 50 patients with symptomatic osteoarthritis of the medial compartment of the knee, the clinical results of high tibial osteotomy (HTO) according to the open wedge osteotomy (OWO) and closed wedge osteotomy (CWO) were compared. In both groups locked plate fixation was used. Clinical and radiological assessments were performed preoperatively and after one year. Postoperative hip-knee-ankle (HKA) correction angles were monitored on standing leg X-rays. The effect of HTO on collateral laxity of the knee was measured with a specially designed varus-valgus device. The WOMAC osteoarthritis index, the modified knee society score (KS) and visual analogue scales (VAS) were used to assess symptoms of osteoarthritis, function, pain and patient satisfaction. At one-year follow-up we found accurate corrections in both groups and the planned correction angles were achieved. No loss of correction was observed. Furthermore, the medial collateral laxity and the patellar height significantly decreased after OWO. Significant improvements of WOMAC and KS scores were found in both groups. All patients had significantly less pain and were very satisfied with the results. Surgery time was significantly longer in the CWO group, and complications were more frequent in this group. Both techniques led to good and comparable clinical results. The choice of whether to perform an open or a closed wedge osteotomy may be based on preoperative patellar height or concomitant collateral laxity.

A sliding stem in revision total knee arthroplasty provides stability and reduces stress shielding.

BACKGROUND AND PURPOSE: In the reconstruction of unicondylar femoral bone defects with morselized bone grafts in revision total knee arthroplasty, a stem extension appears to be critical to obtain adequate mechanical stability. Whether stability is still assured by this reconstruction technique in bicondylar defects has not been assessed. The disadvantage of relatively stiff stem extensions is that bone resorption is promoted due to stress shielding. We therefore designed a stem that would permit axial sliding movements of the articulating part relative to the intramedullary stem. METHODS: This stem was used in the reconstruction with impaction bone grafting (IBG) of 5 synthetic distal femora with a bicondylar defect. A cyclically axial load was applied to the prosthetic condyles to assess the stability of the reconstruction. Radiostereometry was used to determine the migrations of the femoral component with a rigidly connected stem, a sliding stem, and no stem extension. RESULTS: We found a stable reconstruction of the bicondylar femoral defects with IBG in the case of a rigidly connected stem. After disconnecting the stem, the femoral component showed substantially more migrations. With a sliding stem, rotational migrations were similar to those of a rigidly connected stem. However, the sliding stem allowed proximal migration of the condylar component, thereby compressing the IBG. INTERPRETATION: The presence of a functional stem extension is important for the stability of a bicondylar reconstruction. A sliding stem provides adequate stability, while stress shielding is reduced because compressive contact forces are still transmitted to the distal femoral bone.

Surgeon's expectations do not predict the outcome of a total knee arthroplasty.

INTRODUCTION: It is fascinating for both the patient and the surgeon to predict the outcome of a TKA at an early stage. Satisfaction after TKA is primarily determined by the preoperative expectations of the patient. The purpose of this study was to investigate if the peri-operative expectations of the surgeon predicted the outcome of a TKA. PATIENTS AND METHODS: A prospective study of 53 primary TKAs was performed. Preoperatively, the surgeon described the assessment of the difficulty of the TKA on a VAS. Immediately postoperative, the surgeon gave his satisfaction VAS about the procedure. After 1 year the surgeon's satisfaction VAS, the patient's satisfaction VAS and the KSCRS were determined. RESULTS: The Spearman's correlation coefficients between the preoperative difficulty assessment, the immediate postoperative satisfaction and the outcome measurements after 1 year were all very poor (-0.01 to 0.23). CONCLUSIONS: The outcome of a TKA depends on multiple factors. Both the surgeon's preoperative assessment of the difficulty and the surgeon's immediate postoperative satisfaction do not independently predict the outcome of a TKA.

Patients poorly estimate the overall costs of a total knee arthroplasty and strongly overestimate the surgeon's fee.

In an attempt to reduce health care expenses, regulated competition between health care providers has been introduced in The Netherlands. As for total hip and knee arthroplasties, health care providers have to publish their prices to make them available for the insurance companies and the public. Eventually, competition between health care providers should result in optimal care for lower prices. The purpose of this study was to define the patients' consciousness of the overall costs and specialist's fee for a total knee arthroplasty. Thirty-nine patients with a recent total knee arthroplasty were asked to estimate the total costs and the surgeon's fee of this procedure. The average overall cost of a total knee arthroplasty in our hospital was Euro 11.500. The orthopaedic surgeon's fee represents a non-negotiable 5% of these total costs. The mean estimate of the overall costs of a total knee arthroplasty by the patients was Euro 10.000 (range: Euro 600 to Euro 55.000). Only 26% of the patients (n = 10) gave an estimate within the accepted "correct" range of Euro 8.500 to Euro 14.500. The surgeon's fee was estimated at 32% (range: 5% to 75%) of the total costs and a majority reckoned the actual fraction of 5% was low. Patients have a poor notion of the overall costs of a total knee arthroplasty and strongly overestimate the specialist's fee. Whether the introduction of budget competition in health care may actually result in a decrease in health care costs remains to be seen.

A pedicle subtraction osteotomy as an adjunctive tool in the surgical treatment of a rigid thoracolumbar hyperkyphosis; a preliminary report.

BACKGROUND CONTEXT: A pedicle subtraction osteotomy can be considered as part of the surgical treatment of a symptomatic sagittal imbalance. The literature on the use of this technique is limited and thus far not applied to a rigid thoracolumbar hyperkyphosis. PURPOSE: To evaluate our preliminary results of a pedicle subtraction osteotomy as an adjunctive tool in the surgical treatment of thoracolumbar kyphotic deformities. STUDY DESIGN/SETTING: Case series METHODS: Eleven patients with a symptomatic kyphotic deformity were treated with a thoracolumbar pedicle subtraction osteotomy in combination with a multilevel correction. The mean follow-up was 42.8 months (range 26-105). The clinical outcome, radiographic correction, and perioperative complications were analyzed. The results in six more traditional indications (ankylosing spondylitis, kyphoscoliosis, congenital and posttraumatic deformity), were compared with the results in a subgroup of five cases with a rigid thoracolumbar hyperkyphosis. RESULTS: All patients had a kyphotic thoracolumbar junction. An average of 5.8 levels was involved in the corrective fusion. A pedicle subtraction was always performed between the level Th10 and L2 to correct the sagittal balance. A lordotic correction of 38.8 (range 25-49) degrees was established with this fusion. The osteotomy contributed 66% (26.9 degrees) of the correction, whereas the remaining correction came from multilevel facetectomies. The visual analogue scale for both pain and impairment improved significantly (p<.005) for the entire group. Statistical analysis on the results for both subgroups separately was inappropriate because of the small number of patients available; however, overall both subgroups appeared to do equally well. All patients were very satisfied with the result and would choose surgical treatment again. No major complications were encountered. CONCLUSIONS: A pedicle subtraction osteotomy is a technically demanding but well tolerated operative procedure for the correction of a kyphotic deformity. This technique can also be considered as an adjunctive tool in the surgical treatment of a rigid thoracolumbar (Scheuermann's) kyphosis.

Transient kyphotic deformity of the thoracolumbar junction resulting from a large abdominal cyst: a case report.

BACKGROUND CONTEXT: Pronounced kyphosis of the thoracolumbar junction is a common orthopedic problem in adolescents and may require prolonged bracing therapy or correction spondylodesis. PURPOSE: To describe a case where a kyphotic deformity was related to gynecological instead of spine pathology. STUDY DESIGN: Case report. METHODS: A 17-year-old girl presented with a structural hyperkyphosis of the thoracolumbar spine and radiographic changes of the involved vertebral end plates. RESULTS: The thoracolumbar hyperkyphosis appeared to have evolved from a massive intra-abdominal ovarian cyst. Endoscopic paracentesis of the cyst resulted in a complete regression of the hyperkyphosis. CONCLUSIONS: A hyperkyphosis is not always related to spine pathology, and other potential causes must be excluded before bracing therapy is initiated.

[Groin pain in athletes]. / Liespijn bij sporters.

Groin pain in young athletes is a common problem, accounting for significant downtime in sports participation. It can be difficult to make the correct diagnosis as groin pain has a wide differential diagnosis, which encompasses acute as well as chronic causative factors. In this article this is illustrated by presenting three cases of patients who attended our hospital. In all three cases the main complaint was sports-related groin pain, and the patients presented with very similar symptoms. However, after further investigation the patients were diagnosed with three very different types of injury: sportsman's hernia; hip labral tear; and pubic osteitis. This emphasises the need for every general practitioner and medical specialist to understand that there is a wide differential diagnosis for groin pain in athletes, in order to be able to implement specific therapy targeting the actual cause of groin pain.

Trochlear osteotomy for patellar instability: satisfactory minimum 2-year results in patients with dysplasia of the trochlea.

Trochlear dysplasia is a predisposing factor for recurrent patellar instability. We evaluated the results of an anterior lateral femoral condyle open wedge osteotomy for treating patellar instability. A total of 16 consecutive patients (19 knees) with symptoms of recurrent patellar instability and trochlear dysplasia identified using a true lateral radiograph of the knee underwent an anterior lateral femoral osteotomy. Outcomes were documented at 2 years minimum follow-up using the Lysholm scale, the patellofemoral score, WOMAC score and standard conventional radiographs. In 17 knees, patients reported good improvement in stability (no dislocations) and most patients had a marked improvement in pain and functional scores at follow-up (mean follow-up 51 months). No serious complications occurred. Anterior femoral osteotomy of the lateral condyle appears to be a satisfactory and safe method for treating patients with patellofemoral joint instability caused by trochlea dysplasia. In selected cases this procedure can be used to correct trochlea dysplasia. In our opinion, the key to a successful treatment of patellofemoral instability is to successfully distinguish the anatomic deficiencies and to correct the anatomical abnormality.

The trochlea is medialized by total knee arthroplasty: an intraoperative assessment in 61 patients.

BACKGROUND: A medialization of the femoral component in a total knee arthroplasty (TKA) causes abnormal patellar tracking, which could result in patellar instability, pain, wear, and failure. Previous reports defined medialization in relation to the neutral position of the femoral component, but omitted to compare it to the anatomical position of the trochlea. We assessed intraoperatively whether there is a systematic error of the position of the prosthetic groove relative to the anatomical trochlea. MATERIAL AND METHODS: A special instrument was developed to measure consecutively the mediolateral position of the anatomical trochlea and the mediolateral position of the prosthetic groove. 3 experienced knee surgeons determined the mediolateral error of the prosthetic groove in primary TKAs in 61 patients. RESULTS: There was a significant medial error of the prosthetic groove relative to the preoperative position of the trochlea, with a mean medial error of 2.5 mm (SD 3.3) INTERPRETATION: Our findings indicate that the trochlea is medialized by TKA. Because a conscious medialization of the femoral component in a TKA produces abnormal patellar tracking patterns, further investigations will be needed to analyze the clinical consequences of this medialization of the trochlea.

Accuracy and initial stability of open- and closed-wedge high tibial osteotomy: a cadaveric RSA study.

We analyzed the difference in angle-correction accuracy and initial stability between open-wedge (OWO) and closed-wedge tibial valgus osteotomy (CWO). Five fresh-frozen pairs of human cadaver lower limbs were used; their bone mineral density (BMD) was measured with DEXA and a planned 7 degrees valgus osteotomy was performed, either with an open (right knees) or closed (left knees) technique. All knees for osteotomy were fixed with a rigid locked plate. In OWO, tricalcium phosphate (TCP) wedges were inserted. The knees were subjected to an increasing cyclic axial load until failure, while measuring the relative displacement of the bony segments with roentgen stereophotogrammetric analysis. The mean postoperative valgus correction angle was 9.5 degrees +/-2.8 degrees for CWO (over-correction of 2.5 degrees ) and 6.2 degrees +/-2.0 degrees for OWO (under-correction of 0.8 degrees ) (P =0.08). The data of displacement under load bearing showed no significant differences in rotations and translations in any direction. No significant correlation between BMD and the moment of failure was found (P =0.27). This study has shown that both methods gave an acceptable correction with a high variation of postoperative correction angles. There was a tendency for over-correction in the CWO group but no significant difference was found. There was no difference in initial stability between CWO and OWO with a rigid locked-plate fixation.