Purpose

To review prospectively collected data on patients undergoing primary total hip arthroplasty utilizing two different cementless acetabular components.

To review prospectively collected data on patients undergoing primary total hip arthroplasty utilizing two different cementless acetabular components.

All patients undergoing primary total hip replacement surgery at our institution are entered prospectively into a database which includes history and physical examination, radiology, WOMAC and SF-36 scores. The patients are re-examined, re-x-rayed and re-scored at 3 months, 6 months and 1 year after surgery and yearly thereafter.

Using this database we are able to identify patients who have undergone total hip replacement using one of two geometric variants of the acetabular component. The first design is hemispherical and the second design has a peripheral rim expansion designed to increase initial press-fit stability.

Five hundred and twenty-seven consecutive primary total hip replacements were identified using either of the geometric variants of the acetabular component. Results at a mean of 7 years revealed a 95.6% survivorship with no significant difference between the two component designs with revision for aseptic loosening as the end point. Functional scores between the two groups of patients also demonstrated no statistically significant difference.

Radiologic assessment, however, showed a difference between the two designs. The hemispherical design which matches the reamer line-to-line had 80% complete osseointegration on final radiologic review while the second design with a peripheral rim expansion had only 57% complete osseointegration. This was statistically significant. The peripherally expanded components also had a greater number of screws inserted at the time of surgery, felt by us to be a reflection of initial surgeon dissatisfaction with component stability at the time of insertion of the component.

The difference in screw numbers was also statistically significant. This study demonstrates that a hemispherical design with line-to-line contact between the acetabular component surface and the acetabular bone is statistically superior in terms of bone ingrowth and probably statistically superior in terms of initial press-fit stability when compared to a peripherally expanded component.

Peripherally expanded components appear to offer no advantage over hemispherical components in terms of clinical outcome and are statistically inferior to hemispherical components in radiologic parameters at 7 years follow-up.

Purpose

To review prospectively collected data on patients undergoing primary total hip arthroplasty utilizing two different cementless acetabular components.

Introduction: This study aimed to determine the accuracy of computer navigation in simulated fixation of femoral neck and supracondylar femoral fractures using different sizes of guidewires and drills from commercially available cannulated screw systems.

Methods: Simulated fracture fixation was performed with 2.5mm, 2.8mm and 3.2mm threaded guidewires and 3.2mm and 5mm drill bits using 20 4th generation synthetic femurs. The drill or guide wire was inserted in the synthetic femurs, using fluoroscopy based computer navigation (24 drills/guidewires in each group). Pre and postoperative fluoroscopy images were acquired with the C-arm and synthetic bone in the same orientations. Virtual and real wire/drill positions were compared, and errors calculated for each diameter of drill/guidewire (sum AP + Lateral error (mm)). Errors were compared using a general linear model with Tukey adjustment for multiple comparisons. Statistical significance at a two-tailed p-value < 0.05.

Results: The mean error for the 5.0mm drill (3.20mm) was significantly less than all the threaded wires (p< 0.05). The mean error for the 3.2mm drill (5.68mm) was significantly less than the 2.5mm guidewire (9.27mm) p< 0.05, and less than the 2.8mm (8.19mm) and 3.2mm (7.14mm) threaded wires.

Discussion: For cannulated screws, the 3.2mm drill was the most accurate size tested. The most accurate drill, 5mm, would allow solid screw insertion. However, its large size may preclude screw repositioning, and unlike a cannulated screw, would not maintain fracture position whilst the screw was being inserted.

The effect of cup geometry in uncemented Total Hip Arthroplasty has not been investigated. We reviewed the radiological and clinical results of 527 primary total hip arthroplasties. We assessed the bone ingrowth potential of two geometric variations of an uncemented cup and compared hydroxyappetite and porous coated shells.

Patients undergoing primary hip arthroplasty between 1997 and 2004 were prospectively entered into an arthroplasty database. Patients were reviewed at 1,2,4,5,8 and 10 years post surgery. Three acetabular shell types were used. These included hemispherical cups with porous or hydroxyapatite coating, and cups with peripheral expansion with porous coating. Radiographs with minimum 1-year follow-up were examined in 542 cases, using digital templating software. Radiographs were assessed for signs of bone in-growth, lucent lines, migration and polyethylene wear. Survivorship analysis was performed using Kaplan-Meier analysis with 95% confidence intervals. Radiological findings and cup type were analysed using Fishers exact test.

Radiological evidence of bone ingrowth was seen in 82% of hemispherical cups, compared with 59% of peripherally expanded cups, which was significant (p,0.05). Bone ingrowth was not affected by the presence of HA coating. The most common diagnoses were osteoarthritis (67%) and avascular necrosis (12%). The mean age was 56 years. Survivorship with revision or impending revision for aseptic loosening was 95.6% at 7 years (95%CI 1.0134-0.8987). The 3 revisions and 1 impending revision for loosening were in patients with avascular necrosis (3) or previous acetabular and femoral osteotomies for DDH (1), with a mean age of 44 years.

Hemispherical shells have improved radiographic outcome in comparison with peripherally expanded components. At 7 years, clinical results are similar for both components.

This prospective controlled clinical trial compares the outcomes of metacarpophalangeal (MCP) arthroplasty in rheumatoid arthritis patients using the Swanson (S) and NeuFlex (N) MCP implants.

Forty hands (thirty-seven patients) were randomised and evaluated preoperatively and at one year following MCP arthroplasty in digits two to five for range of motion (ROM; active and passive extension and flexion), ulnar drift and grip strength.

Both implants restored extension and corrected flexion deformities. There was no significant difference in extension of all digits (summed) between the NeuFlex and Swanson implants (N: −20.8°; S: −13.8°; p=0.29). The NeuFlex implant, which is pre-flexed at 30°, preserved more flexion at the MCP joint than the Swanson implant in all digits (summed) (N:74.5°; S:55.8°; p=0.005), with the greatest difference observed in the fifth digit (N:69.6°; S:48.7°; p=0.009). The total arc of motion improved in all digits, with no significant differences between the Neu-Flex and Swanson groups in the second through fourth digits (N:53.8°; S:43.8°; p=0.154); a significantly greater improvement was observed in the NeuFlex group for the fifth digit (N:53.3°; S:42.5°; p=0.028). Both implants corrected ulnar drift deformity, while neither led to loss of grip strength.

Hand function as measured by Sollerman score and Michigan Hand Questionnaire (MHQ) improved significantly in both groups (p=0.0119, p< 0.0001, respectively) with no significant difference between the Swanson and NeuFlex implants, except for MHQ function, aesthetics, and overall scores, which demonstrated superiority of the Swanson.

Overall, there was a significant improvement in the range of motion, deformity and grip strength following MCP arthroplasty for the full patient group. While both implants restored similar amounts of extension, the NeuFlex implant maintained greater flexion and total range of motion, with the greatest difference in the fifth digit. The Swanson implant had better MHQ function and aesthetics subscores.

The purpose of this study was to evaluate functional outcome following supracondylar femur fractures using patient-based outcome measures.

Patients having sustained supracondylar femur fractures between 1990 and 2004 were identified from the fracture databases of two level-one trauma centres. Three patient-based outcome measures, the Short Form-36 (SF-36) Version two, the Short Musculoskeletal Functional Scale (SMFA), and the Lower Extremity Functional Scale (LEFS) were used to evaluate functional outcome. Each patient’s medical record was also reviewed to obtain information regarding potential predictors of outcome, including age, gender, fracture type (AO classification), presence of comorbidities, smoking status, open vs. closed fracture, and occurrence of complications. Univariate and multivariate models were then used to identify significant predictors of outcome, as reflected in the SMFA bother and dysfunction scores.

Sixty-one patients (thirty-five males and twenty-six females) with an average age (at time of injury) of 53 ± 18 years consented to participate. The average length of follow-up was 64 ± 34 months from the time of injury. Mean SF-36 V2 scores were lower than Canadian population norms indicating decreased function or greater pain, while mean SMFA scores were higher than published population norms indicating greater impairment and bother. The mean LEFS score was 40.78 ± 15.90 out of a maximum score of eighty. At the univariate level, the presence of complications was a significant predictor of both the SMFA bother (p=0.002) and dysfunction scores (p=0.015), while positive smoking status was a significant predictor of the bother score (p=0.002). Based on a multivariate linear regression model, the presence of complications (p=0.013) and positive smoking status (p=0.011) were both significant predictors of a higher SMFA bother score. In the multivariate model for SMFA dysfunction score, the presence of complications (p=0.014) and the presence of comorbidities (p=0.017) were significant predictors of a higher score.

Comparing SF-36 and SMFA scores with published population norms, supracondylar femur fractures were associated with residual impact. Based on our analysis, smoking, the presence of medical comorbidities at the time of fracture, and the occurrence of complications following fracture repair were the main predictors of poorer patient outcomes following supracondylar femur fracture.

Metacarpophalangeal (MP) arthroplasty restores function, corrects deformity and reduces pain in patients with rheumatoid arthritis (RA). In a randomised controlled trial of MP hand reconstruction, we investigated RA patient motivations and expectations and whether self-reported patient satisfaction with appearance, function and pain correlated with objective and subjective outcome measures.

From forty patients (one hundred and sixty joints), randomised for an MP arthroplasty trial, we collected preoperative and postoperative objective measures (range of motion (ROM), ulnar drift, JAMAR grip strength), subjective measures (Michigan Hand Questionnaire (MHQ), Sollerman Hand Function test), pre-operative patient-reported motivations and expectations of surgery (appearance, function, pain), and postoperative patient-reported improvement and satisfaction with surgery (appearance, function, pain, overall). Spearman correlations determined associations between patient satisfaction and specific outcome measures.

Mean age was 60.3 years, mean disease duration at time of surgery 22.9 years, mean follow-up time 386.4 days, and 87.5% of patients were female. Seven of forty patients (17.5%) rated improved function as the single biggest motivator for surgery, one (2.5%) rated pain, the remainder (80%) rated two or more motivators equally high. Function was rated as the most important or one of the most important motivators for surgery by 92.5% of patients, pain by 67.5% and appearance by 47.5%. Several MHQ subscores (function, work, ADL) were moderately correlated (|rho|=0.67, 0.52, 0.54, respectively), and the Sollerman Score was weakly correlated (|rho|=0.39) with self-reported satisfaction with function, but ROM and grip strength were not (|rho||< 0.25). Self-reported satisfaction scores for appearance, pain and overall were moderately correlated with analogous MHQ subscores (|rho|=0.78, 0.65, 0.71, respectively).

Patient expectations of MCP arthroplasty were uniformly high. The greatest motivation for surgery was functional improvement. Pain was highly ranked, but nearly half of the patients rated hand appearance as one of the highest co-ranked motivators. Patient satisfaction correlated poorly with traditional outcome measures (ROM, grip strength) and moderately with subjective outcome measures (MHQ). Aesthetic appearance is probably underrated as a motivator for surgery and determinant of satisfaction.

Health utilities indicate the value of a given health state. They are essential components of decision analyses, and economic evaluations. In the area of total shoulder arthroplasty (TSA) we were unable to find literature estimating changes in utilities or the effect of method of obtaining utilities. The purpose of this pilot study was to describe the trajectory of utility scores before and after TSA using three approaches: the EQ-5D and the Health Utilities Index (HUI2 and HUI3) self-report format.

Twenty-four patients undergoing TSA at two teaching hospitals (Boston and Toronto) were assessed twice preoperatively, as well as at four and twelve weeks follow-up by self report mailed survey. At each survey all three utility estimates were obtained. Demographic and functional status was also gathered. The EQ-5D is a five item questionnaire which scores into a profile to which utility weights obtained from the developers were applied. The HUI self-report is a fifteen item scale obtaining a score on eight domains. A multiplicative formula is used to assign utility weights to these responses. Descriptive analysis of the sample, baseline characteristics and change in utility were completed. Intra-class correlation coefficients were used to calculate test-retest reliability between the two preoperative visits. Standardised response means (SRM) (mean change/SD of change) and relative efficiency (RE=ratio of SRM2) were calculated. Individual trajectories of change were graphed and examined for trends.

Twenty-four patients participated with average age of sixty-seven years, 58% were female and experienced large improvements in disability and pain (mean change DASH = 18.9/100, SPADI Pain = 30.3/100). Utility scores had low to moderate correlations with each other (0.26–0.68). Mean baseline scores were low (EQ5D=0.44, HUI2=0.68, HUI3 = 0.50). The average change in utility is shown in the following table along with effect size estimations and test-retest reliability.

Patients experience clinically important and statistically significant changes in their utility values even in the early stages of recovery after TSA (three months). The HUI3 and EQ-5D were most responsive to changes experienced in this sample.