Femoral loosening of high-flexion total knee arthroplasty: the effect of posterior cruciate ligament retention and bone quality reduction.

High-flexion total knee arthroplasty (TKA) may be more sensitive to femoral loosening than conventional TKA as the knee joint force increases during deep flexion. The objective of this study was to evaluate whether the probability of femoral loosening is equal in posterior cruciate ligament (PCL) retaining and substituting high-flexion knee implants and whether loosening is related to femoral bone quality. A three-dimensional finite element (FE) model of the knee was developed and a weight-bearing deep knee bend up to 155° was simulated. PCL conservation considerably increased the compressive tibio-femoral joint force as a maximal force of 4.7-6.0 × bodyweight (BW) was found, against a maximal force of 4.0 × BW for posterior-stabilized TKA. Roughly 14% of the fixation site beneath the anterior femoral flange was predicted to debond on the long-term in case of cruciate-retaining TKA compared to 20% in case of posterior-stabilized TKA. Reducing the femoral bone quality to 50% of its original bone mineral density increased the amount of potential anterior failure for cruciate-retaining TKA to 22% and posterior-stabilized TKA to 24%. We therefore conclude that the femoral fixation site has a similar failure potential for both cruciate-retaining and posterior-stabilized high-flexion TKA.

Influence of preparation techniques to the strength of the bone-cement interface behind the flange in total knee arthroplasty.

INTRODUCTION: Recent clinical studies show an increased risk of femoral loosening in high-flexion TKA. Loosening seems to occur behind the anterior flange, which is covering both cancellous bone and cortical bone. It is important to optimize the interface strength between cement and both bone types to increase femoral component fixation. This study was performed to determine the cement-cortical bone interface strength for different preparation techniques. MATERIAL AND METHODS: A pure tensile and shear force was applied to interface specimens. The cortical surface area was prepared in three different ways: (1) Unprepared cortical bone with periosteum; (2) Periosteum removed and cortical bone roughened with a rasp; (3) Periosteum removed and three Ø 3.2mm holes drilled through the cortex. A reference group was added with a cancellous bone surface. RESULTS: The interface tensile strength of Group 1 was 0.06 MPa and the shear strength was 0.05 MPa. For Group 2, respectively 0.22 MPa and 1.12 MPa. For Group 3, respectively 1.15 MPa and 1.77 MPa. For cancellous bone a tensile strength of 1.79 MPa and a shear strength of 3.85 MPa were measured. CONCLUSION: The strength of the cement-cancellous bone interface is superior to the cement-cortical bone interface. The preferred preparation technique of the cortical bone is to remove all the periosteum and drill holes through the cortex within the footprint of the anterior flange, to prevent cortical weakening. CLINICAL RELEVANCE: Ultimately, the proposed preparation technique will lead to longer implant survival, particularly for prostheses which are used in the high-flexion range.

Physical examination and in vivo kinematics in two posterior cruciate ligament retaining total knee arthroplasty designs.

The aim of this study was to investigate anteroposterior instability in the CKS and the PFC total knee arthroplasty (TKA) designs. Physical examinations, including VAS, IKS and WOMAC were performed in combination with a detailed fluoroscopic measurement technique for three-dimensional kinematic assessment of TKA design function. Anteroposterior instability rated with the IKS was not significantly different (p=0.34), but patients with a CKS design showed more limitations according to the WOMAC joint stiffness total score, and for items regarding higher flexion activities in the WOMAC score for knee disability. Kinematic analyses showed that the CKS design tended to have more anterior sliding of the femur on the tibia during mid- and deep flexion activities. The sliding distance was larger at the medial than at the lateral side. This phenomenon has also been described for posterior cruciate ligament deficient knees. Furthermore, the CKS design showed a significantly lower range of tibial rotation (p<0.05) from maximum extension to maximum flexion during deep knee bend activities. Kinematic differences can be ascribed to posterior cruciate ligament deficiency/laxity or differences in TKA designs.

Continuous femoral nerve block after total knee arthroplasty?

BACKGROUND: A continuous femoral nerve block is frequently used as an adjunct therapy after total knee arthroplasty (TKA). However, there is still debate on its benefits. METHODS: In this prospective, randomized study, patients received a basic analgesic regimen of paracetamol and dicloflenac for the first 48 h postoperatively. In addition, the study group received a continuous femoral nerve block. A morphine patient-controlled analgesia pump was also available as a rescue analgesic to all the patients. Patients' numeric rating scores for pain, the amount of morphine consumed and its side effects during the first 48 h were recorded. Knee flexion angles achieved during the first week were registered. Three months postoperatively, patients completed Western Ontario and McMaster Universities Osteoarthritis Index and Knee Society Score. RESULTS: The study group (n=27) had less pain (P=0.0016) during the first 48 h, was more satisfied with the analgesia (P<0.001) and used less morphine (P=0.007) compared with the control group (n=26). Fewer patients were nauseated, vomited or were drowsy in the study group (P=0.001). Also, the study group achieved better knee flexion in the first 6 days after surgery (P=0.001), with more patients reaching 90 degrees flexion than the control group. However, after 3 months, there were no significant functional differences between the groups. CONCLUSION: A continuous femoral nerve block leads to better analgesia, less morphine consumption and less morphine-related side effects after TKA. Early functional recovery is improved, resulting in more patients reaching 90 degrees knee flexion after 6 days. However, after 3 months, no significant functional benefits were found.

Survival of massive allografts in segmental oncological bone defect reconstructions.

Reconstructions of large segmental bone defects after resection of bone tumours with massive structural allografts have a high number of reported complications including fracture, infection and non-union. Our goal is to report the survival and complications of massive allografts in our patients. A total of 32 patients were evaluated for fracture, infection, non-union rate and survival of their massive allograft reconstructions. The average follow-up for this group was five years and three months. The total fracture rate was 13% with a total infection rate of 16%. We found a low union rate of 25%. The total survival of the allografts was 80.8% (+/- 18.7%) after five years. We found a five-year allograft survival of 80.8% which is comparable with other studies.

How to quantify knee function after total knee arthroplasty?

Total knee arthroplasty (TKA) is being undertaken in a younger population than before and as a result the functional demands on the knee are likely to be increasing. As a consequence, it is important to define quantitative functional knee tests that can monitor any increase. A valuable functional knee test has to be able to distinguish small differences (selectivity) and has to be independent of pain (content validity). In this study, patient-based questionnaires (WOMAC and Knee Society score) and performance-based tests (sit-to-stand movement, maximal isometric contraction and timed-up-and-go) were used to assess which of these tests are selective and valid to measure knee function. Tests were considered to be selective if they could discriminate between knee patients and healthy control subjects, and to have functional content validity if they were relatively independent of pain. Twenty-eight patients were measured 16 months after surgery and compared to a healthy control group of 31 subjects. The sit-to-stand movement and timed-up-and-go test were both selective and functionally content valid. The timed-up-and-go test can be used for a quick initial assessment of global function and the sit-to-stand movement as a more biomechanical instrument identifying how the knee function of the patient is affected.

Functional evaluation of the TKA patient using the coordination and variability of rising.

A kinematic analysis of the knee function is important for the evaluation of total knee arthroplasties (TKA). We used the coordination and variability of rising from a chair as functional knee parameters. Twelve knee patients were measured prior to surgery (=pre-TKA group) and one year after surgery (=post-TKA group). A group of 15 healthy, age-matched subjects was selected as control group. The WOMAC questionnaire, frequently used by orthopaedic surgeons, was administered prior to the test. The test consisted of 10 times rising from a low chair and 10 times from a high chair. Knee and hip angles and angular velocities were measured with electrogoniometers. The relative phase (=MRP) between hip and knee was a measure for the coordination of rising and the standard deviation of the relative phase of the 10 trials (=SRP) was a measure for the variability. The coordination and variability of rising of the TKA patients were compared to the control group, and the relationship with the WOMAC questionnaire was calculated. The coordination of rising from a high chair and the variability of rising from both chair heights were significantly different for the pre-TKA group compared to the control group (p<0.05). The post-TKA group showed no significant differences with the control group, which indicates a functional recovery after TKA implantation. The functional parameters correlated adequately with the subjective WOMAC questionnaire. This study showed that our method is an objective measure of functionality and it will be worthwhile to use it as an additional evaluation tool.

The feasibility of total ankle prosthesis for severe arthropathy in haemophilia and prothrombin deficiency.

The standard treatment for end-stage arthropathy of the ankle joint in haemophilia has been fusion of the ankle joint. Total ankle replacement is used in osteoarthritis and especially in rheumatoid arthritis with good medium-term results. In this case series three patients are being described, in which a total of five total ankle replacements have been preformed. After a median follow up of 4.3 years (range 1-8.7) all prostheses were still in place and did not show any signs of loosening. Clinical scores showed a good to excellent result. In this small series total ankle replacement in patients with bleeding disorders show promising results. Further studies are needed to show the value of this relatively new type of surgery in haemophilic patients.

Are surgeons equally satisfied after total knee arthroplasty?

INTRODUCTION: We performed a clinical follow-up study to investigate whether three orthopaedic surgeons were equally satisfied after total knee arthroplasty (TKA). PATIENTS AND METHODS: Thirty-six patients (39 TKAs, mean follow-up 12 months) were reviewed, using the Knee Society Clinical Rating System (KSCRS). For the assessment of satisfaction a visual analogue scale (VAS) was used. RESULTS: We did not find a significant difference in satisfaction between the surgeons. However, there was a significant difference in the knee score and function score of the KSCRS as evaluated by the orthopaedic surgeons (p=0.006 and p=0.04, respectively). The correlation between the knee score and the surgeons' satisfaction was high, which indicates that pain, range of motion and deformity are important success criteria for surgeons. CONCLUSIONS: In this study, surgeons scored differently in the KSCRS but were equally satisfied after TKA.

Improvement in technique for arthroscopic ankle fusion: results in 15 patients.

We retrospectively assessed time until consolidation, complications, and functional results according to Morgan from the clinical charts and radiographs of 15 arthroscopic ankle fusions. In 11 patients unilateral distraction and crossed screw placement over the fusion area through tibia and fibula were used (group A); in 4 patients a technique of bilateral distraction and parallel screw placement from the dorsal side of the tibia into the neck of the talus was used (group B). In group A there were two cases of insufficient compression at the arthrodesis site, three cases of suboptimal compression, and five cases of malposition of the screws. In all cases in group B good compression and fixation was achieved, and no case of malpositioning of screws occurred. There was nonunion in 3 of 11 patients in group A and in none of the four patients in group B. Time until fusion was 23.3 in group A and 12.5 weeks in group B. Functional results were better in group B. The initial experiences with our technique of bilateral distraction and parallel screw placement are therefore promising. Screw placement is easier and optimal compression and fixation are achieved. We feel that this technique should be considered when performing an arthroscopic ankle fusion.

Open capsular shift for multi directional shoulder instability.

We evaluated the outcome of open antero-inferior capsular shift in 17 patients with multidirectional instability of the shoulder who failed to respond to conservative treatment. Six shoulders presented with secondary impingement syndrome and 11 with involuntary instability. The mean duration of follow-up was 39 months (range 7-89 months). Based on the Rowe and Constant scores and the 12-item questionnaire of Dawson, the results were rated excellent in 14 patients, fair in 2 and poor in 1. All but 2 patients were satisfied with the results, although 6 patients experienced some residual pain, and 4 suffered minor instability. There were no neurovascular complications, infections or symptomatic posterior instability. Open antero-inferior capsular shift yields promising short-term to medium-term results in multidirectional, involuntary instability of the shoulder.

Patient satisfaction after total knee arthroplasty: a comparison between subjective and objective outcome assessments.

We used a visual analog scale (VAS) to assess the satisfaction after total knee arthroplasty (TKA) in a group of 108 patients (126 TKAs) with short-term to medium-term follow-up. We also used the Knee Society scoring system, Western Ontario and McMasters Universities Osteoarthritis Index (WOMAC), pain VAS, and survival analysis. A comparison between the subjective and objective outcome systems revealed only poor correlations. This comparison suggests that the concerns and priorities of patients and surgeons differ. The outcome assessed with the satisfaction VAS revealed a significantly better subjective outcome in rheumatoid arthritis patients compared with osteoarthritis patients, whereas Knee Society scores were not different. The satisfaction VAS provides additional information about subjective outcome after TKA.

Change in bone mineral density in patients with rheumatoid arthritis during the first decade of the disease.

OBJECTIVE: Rheumatoid arthritis (RA) has been reported to be associated with bone loss during the first years of the disease. The magnitude of this problem after the initial years has not yet been evaluated. In the present study, the change in bone mineral density (BMD) in patients with recent-onset RA as well as the effects of inflammation, mobility, and the use of prednisone on this change were studied in the first decade of the disease. METHODS: BMD was measured twice in 76 RA patients with mean disease durations of 2.35 years at the first BMD measurement and 8.90 years at the second BMD measurement. BMD was measured in both hips using dual x-ray absorptiometry. Results were expressed as mean +/- SEM Z scores (using age- and sex-matched reference values) and as mean +/- SEM percent change in BMD (in gm/cm2) per year. The effects of inflammation, mobility, and the use of prednisone on change in BMD were evaluated using multiple linear regression analyses. RESULTS: At the first BMD measurement, RA patients had lower BMD compared with the reference values (Z score -0.42+/-0.11, 95% confidence interval [95% CI] -0.64, -0.20). Between the 2 measurements, we observed a small decrease in BMD of -0.28+/-0.11%/year (95% CI -0.07 to -0.49). However, the rate of bone loss was smaller than expected. The Z score increased by 0.13+/-0.05 between the 2 BMD measurements (95% CI 0.02, 0.23). Only the use of prednisone was significantly associated with increased bone loss. In a separate analysis that included only postmenopausal women, increased physical activity and longer time since menopause were both associated with decreased bone loss. In this subgroup of patients, the use of prednisone was significantly associated with increased bone loss as well. A high erythrocyte sedimentation rate was associated with increased bone loss, but this did not reach statistical significance. CONCLUSION: After the initial years of the disease, bone loss in RA patients is lower than expected compared with age- and sex-matched reference values. Postmenopausal RA patients with low levels of physical activity are at increased risk of losing bone. Use of prednisone was the only variable consistently associated with reduction in BMD in RA patients.

Distal femoral bone mineral density after total knee arthroplasty: a comparison with general bone mineral density.

The bone mineral density (BMD) of the distal femur may decrease after cemented total knee arthroplasty (TKA) as a result of the stress shielding effect of the femoral component. The purpose of the study was to determine the changes in BMD of the distal femur compared with those of the femoral necks and the lumbar spine after cemented TKA. BMD of two regions of interest in the distal femur, both femoral necks and the lumbar spine was measured with dual-energy X-ray absorptiometry in 10 patients (age range 41-80 years, mean 62 years) with 12 TKAs preoperatively and during follow-up for 1 year after surgery. The hip and spine measurements were performed for comparison to assess if general changes in BMD occurred after TKA. The median decrease in BMD in the region behind the anterior flange of the femoral component was 22% (95% CI: 12%-33%), while the average decrease in the region just above the femoral component was 8% (95% CI: 2%-13%). The difference in change of BMD between both regions before and 1 year after TKA was significant (p = 0.03). We found less than 1% difference in BMD of both femoral necks and the lumbar spine on average between the preoperative and 1 year follow-up measurements (not significant). A significant periprosthetic distal femoral bone resorption occurred after TKA. BMD of the femoral necks and lumbar spine did not differ 1 year after TKA.

The GSB total knee arthroplasty. A medium- and long-term follow-up and survival analysis.

From 1981 to 1987, 77 GSB-II total knee arthroplasties were implanted in 65 patients. There were 23 men and 42 women aged on average 60 years old (range 30-85 years). The diagnosis was osteoarthritis (OA) in 21 knees, rheumatoid arthritis (RA) in 44 knees, and other in 12 knees. A clinical and radiological follow-up was performed in two stages after a mean of 6.7 years (61 knees) and 14.8 years (22 knees) to assess the medium- and long-term results and to determine if deterioration had occurred after mid-term follow-up. A survival analysis was done with two endpoints: (1) revision, and (2) revision, moderate or severe pain and lost to follow-up (worst-case scenario). At the last follow-up 36 patients (44 knees) had died, 2 patients (2 knees) refused examination, and 3 patients (3 knees) were lost to follow-up. Six knees had been revised for malposition (1.3%), septic (3.9%) and aseptic (2.6%) loosening. The mean Knee Society score after 6.7 and 14.8 years was 85 points (OA 82 points, RA 87 points). Lateralisation, subluxation or dislocation of the patella was present in 8 of 17 knees at the last follow-up. The 6- and 15-year survival rates with revision as the endpoint were 95% (CI 89%-100%) and 87% (CI 65%-100%), respectively. For the worst-case scenario, the 6- and 15-year survival rates were 95% (CI 89%-100%) and 56% (CI 0%-100%), respectively. The medium- and long-term results of the GSB-II total knee arthroplasty were good, and a decline in the knee score did not occur beyond the mid-term follow-up. Patella complications were abundant, and a marked decrease in implant survival was noted when moderate or severe pain and lost to follow-up were included as endpoints.

Synovial macrophage depletion with clodronate-containing liposomes in rheumatoid arthritis.

OBJECTIVE: To assess whether intraarticular (IA) administration of clodronate liposomes results in local macrophage depletion in patients with rheumatoid arthritis (RA). Primary goals were to address both the immunohistologic and potential toxic effects of this approach. Moreover, the correlation between immunohistologic findings and clinical assessments of disease activity and cartilage damage were assessed. METHODS: An open study was conducted in consecutive RA patients who were scheduled for knee joint replacement in our department. Synovial biopsy tissue was obtained from the knee joint at 2 weeks before and at the time of surgery. This protocol was controlled for safety and immunohistologic concordance in 6 patients. One week before surgery, 10 patients received a single IA dose of clodronate liposomes. Staining of synovial tissue for cell markers (CD68, CD14, CD3, CD38) and adhesion molecules (vascular cell adhesion molecule 1 [VCAM-1], intercellular adhesion molecule 1 [ICAM-1]) was assessed by 2 blinded observers. Local and systemic parameters of disease activity were measured before each intervention. Cartilage damage was scored using standard radiologic techniques at baseline and during surgery. RESULTS: A single IA dose of clodronate liposomes significantly reduced the number of CD68-positive cells (P = 0.005) and the expression of ICAM-1 and VCAM-1 in the synovial lining (P = 0.013 and P = 0.039, respectively). The intervention did not affect fibroblast-like synoviocytes, T cells, or plasma cells. No immunohistologic changes were observed in the control group. The procedure was well tolerated. The levels of ICAM-1 and VCAM-1 in the sublining layers correlated with the extent of macroscopic synovitis (P < 0.0005 and P < 0.005, respectively). The expression of ICAM-1 and CD14 in the sublining correlated with the levels of C-reactive protein (P < 0.0005 and P < 0.01, respectively). Cartilage destruction was correlated only with the expression of CD68 in the sublining (P = 0.02). CONCLUSION: A single IA administration of clodronate liposomes leads to macrophage depletion and decreased expression of adhesion molecules in the synovial lining in patients with longstanding RA. The procedure is well tolerated, and its therapeutic potential is currently under investigation. The expression of adhesion molecules in the sublining layers reflects ongoing inflammation.

The role of femoral stem extension in total knee arthroplasty.

Although stemmed femoral components often are used in revision total knee arthroplasty, no quantitative comparison of the relative stability of a femoral component with and without a stem has been performed previously. A radiostereophotogrammetric analysis was performed to determine the influence of stem extension on mechanical stability in a laboratory experiment. In addition, the contribution of impacted morselized bone graft used for reconstruction of bone defects to stability was determined. Ten fresh frozen distal femoral specimens, of which the bone mineral density was measured, were prepared to fit a cemented femoral component with an uncemented stem. A cyclic axial load of 750 N was applied to the medial part of the femoral component. The loading test was repeated after creation of a standard, unicondylar, uncontained medial bone defect, after reconstruction of the defect with impacted morselized bone graft, after disconnecting the stem from the component, and after removal of the morselized bone graft. A significant difference was found in rotation and translation of the femoral component with the stem and after its functional removal. The femoral component rotated significantly into varus and internal rotation, and the tip of the stem translated significantly laterally after disconnection of the stem. A linear correlation between bone mineral density in the femoral neck and the radiostereophotogrammetric motion data was absent, but a bone mineral density threshold level of 0.55 g/cm2 was present, below which stability decreased considerably. Morselized bone graft provided only a minor contribution to stability compared with a stem.

Impacted morsellized bone grafting and cemented primary total hip arthroplasty for acetabular protrusion in patients with rheumatoid arthritis: an 8- to 18-year follow-up study of 36 hips.

Between 1979 and 1989, we performed 36 primary total hip replacements in 31 rheumatoid arthritis patients with protrusio acetabuli. The deficient acetabulum was reconstructed with autologous morsellized bone grafts from the femoral head. 3 patients were lost to follow-up. 12 patients (13 hips) died within 8 years postoperatively, none had a revision. 16 patients (20 hips) were reviewed at an average follow-up of 12 (8-18) years. In 2 hips, a revision was performed for aseptic loosening of the acetabular component, 65 and 8 years after primary surgery, which means a 90% (95% CI: 77%-100%) survival rate at 12 years (Kaplan Meier analysis). This technique is a good option in cases with protrusio acetabuli due to rheumatoid arthritis.

Autologous morsellised bone grafting restores uncontained femoral bone defects in knee arthroplasty. An in vivo study in horses.

The properties of impacted morsellised bone graft (MBG) in revision total knee arthroplasty (TKA) were studied in 12 horses. The left hind metatarsophalangeal joint was replaced by a human TKA. The horses were then randomly divided into graft and control groups. In the graft group, a unicondylar, lateral uncontained defect was created in the third metatarsal bone and reconstructed using autologous MBG before cementing the TKA. In the control group, a cemented TKA was implanted without the bone resection and grafting procedure. After four to eight months, the animals were killed and a biomechanical loading test was performed with a cyclic load equivalent to the horse's body-weight to study mechanical stability. After removal of the prosthesis, the distal third metatarsal bone was studied radiologically, histologically and by quantitative and micro CT. Biomechanical testing showed that the differences in deformation between the graft and the control condyles were not significant for either elastic or time-dependent deformations. The differences in bone mineral density (BMD) between the graft and the control condyles were not significant. The BMD of the MBG was significantly lower than that in the other regions in the same limb. Micro CT showed a significant difference in the degree of anisotropy between the graft and host bone, even although the structure of the area of the MBG had trabecular orientation in the direction of the axial load. Histological analysis revealed that all the grafts were revascularised and completely incorporated into a new trabecular structure with few or no remnants of graft. Our study provides a basis for the clinical application of this technique with MBG in revision TKA.