This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for Total Hip Replacement With the Answer® Hip Stem and Ranawat/Burnstein® Shell Using Simplex® or Palacos® Bone Cement (NCT00588861), a non-randomized na study. The primary outcome is Harris Hip Score.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00588861 |
| Phase | NA |
| Condition | Osteoarthritis, Hip, Traumatic Arthritis of Hip |
| Allocation | Non-Randomized |
| Design model | Parallel |
| Masking | None (open label) |
| Enrollment | 400 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Biomet Orthopedics, LLC |
| Results posted | Yes |
2. Clinical Question
Population
The registry lists osteoarthritis of the hip and traumatic arthritis of the hip as the conditions of interest. The study concerned patients undergoing total hip replacement. The primary outcome description says that the intended population was patients who returned for follow-up according to protocol; it also states that no patients returned at the primary outcome time point, so no patients were analyzed at 10 years. The record lists enrollment of 400, but does not explain how that figure relates to the number followed at each time point.
Intervention
One arm used the Answer® hip stem with Simplex bone cement. The registry describes this as femoral stem replacement with the Answer® hip stem and Simplex Bone Cement.
Comparator
The other arm used the Answer® hip stem with Palacos bone cement. The registry describes this as femoral stem replacement with the Answer® hip stem and Palacos Bone Cement. Allocation was non-randomized, so these arms should not be treated as a like-for-like randomized comparison.
Primary question
The stated primary outcome was Harris Hip Score at 10 Years Post-Operative. The intended question was how the score was distributed among patients who returned for follow-up. The record gives the score’s range and interpretive categories, but reports that no patients were analyzed at the specified time point. Consequently, it does not provide an observed primary outcome result with which to compare the cement groups.
3. Trial Design
The registry describes a parallel, non-randomized study with no masking. Its stated purpose was to document clinical outcomes for devices used in total hip replacement, including the Answer® hip stem, the Ranawat/Burnstein® acetabular shell, and Simplex® or Palacos® bone cement. The arm descriptions distinguish the use of Simplex cement from the use of Palacos cement with the Answer® hip stem. Although the overall purpose mentions several devices, the two arm descriptions posted in the record focus on the hip stem and the cement used with it.
Non-randomized allocation means the registry does not describe participants being assigned to the cement groups by chance. The record does not explain how treatment assignment was determined, whether clinicians or participants selected the cement, or whether allocation changed over time. Those details are not reported in the registry record. Without random allocation, differences between the groups could reflect characteristics that were already different between their participants, as well as any differences associated with the cement used. The record does not provide information that would establish whether such factors were measured or adjusted for.
The study is listed as having no masking. The registry does not state which people, if any, knew the cement assignment during treatment, follow-up, or outcome assessment. A lack of masking can matter when outcomes involve clinical assessment, but the record does not describe procedures used to reduce the influence of knowledge of treatment assignment.
The registry lists an enrollment of 400 and gives a start date of 2002-09 and primary completion date of 2010-05. The study status is terminated. A reason for termination is not reported in the registry record. These administrative details do not establish how many participants completed follow-up or contributed to each outcome. For the primary outcome at 10 Years Post-Operative, the record explicitly states that no patients were analyzed.
The registry classifies the study phase as NA. It lists two outcome measures and zero analyses. It does not report a detailed statistical analysis plan, sample-size justification, or explanation of the endpoint follow-up procedures. The design information therefore supports a description of the study structure, but not a reconstruction of its intended analytic decisions.
4. Participant Flow and Accounting
The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.
Before assignment: The patients were assigned to each group according to the bone cement used with the implant.
Pre-Operative
| Stage | Answer Stem Utilizing Simplex Cement | Answer Stem Utilizing Palacos Cement |
|---|---|---|
| STARTED | 202 | 200 |
| COMPLETED | 107 | 114 |
| NOT COMPLETED | 95 | 86 |
Reasons for not completing this period:
| Reason | Answer Stem Utilizing Simplex Cement | Answer Stem Utilizing Palacos Cement |
|---|---|---|
| Patients Did Not Complete Preop Data | 95 | 86 |
6 Months
| Stage | Answer Stem Utilizing Simplex Cement | Answer Stem Utilizing Palacos Cement |
|---|---|---|
| STARTED | 107 | 114 |
| COMPLETED | 9 | 41 |
| NOT COMPLETED | 98 | 73 |
Reasons for not completing this period:
| Reason | Answer Stem Utilizing Simplex Cement | Answer Stem Utilizing Palacos Cement |
|---|---|---|
| Patients did not return for follow-up | 98 | 73 |
1 Year
| Stage | Answer Stem Utilizing Simplex Cement | Answer Stem Utilizing Palacos Cement |
|---|---|---|
| STARTED | 107 | 114 |
| COMPLETED | 18 | 32 |
| NOT COMPLETED | 89 | 82 |
Reasons for not completing this period:
| Reason | Answer Stem Utilizing Simplex Cement | Answer Stem Utilizing Palacos Cement |
|---|---|---|
| Patients did not return for follow-up | 89 | 82 |
2 Years
| Stage | Answer Stem Utilizing Simplex Cement | Answer Stem Utilizing Palacos Cement |
|---|---|---|
| STARTED | 107 | 114 |
| COMPLETED | 15 | 27 |
| NOT COMPLETED | 92 | 87 |
Reasons for not completing this period:
| Reason | Answer Stem Utilizing Simplex Cement | Answer Stem Utilizing Palacos Cement |
|---|---|---|
| Patients did not return for follow-up | 92 | 87 |
Analysis population for the primary outcome, as defined in the registry: This population represents patients that returned for follow-up per protocol. Because no patients returned at the primary outcome measure time frame (10 years), 0 patients were analyzed at 10 years.
5. Baseline Characteristics
The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.
| Characteristic | Unit | Answer Stem Utilizing Simplex Cement | Answer Stem Utilizing Palacos Cement | Total |
|---|---|---|---|---|
| Participants analysed | 202 | 200 | 402 | |
| Age, Continuous | years | 73 (46 to 93) | 76 (54 to 95) | 75 (46 to 95) |
| Sex: Female, Male: Female | Participants | 127 | 142 | 269 |
| Sex: Female, Male: Male | Participants | 75 | 58 | 133 |
6. Primary Endpoint
The registry lists the primary outcome as Harris Hip Score, measured over 10 Years Post-Operative.
| Element | Registry entry |
|---|---|
| Result type | N/A |
| Measure of spread | not applicable |
| Unit | not stated |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is the Harris Hip Score at 10 Years Post-Operative. The registry describes the score on a range from 0 to 100, with 100 as the highest score and 0 as the lowest. It defines 90-100 as Excellent, 80-89 as Good, 70-79 as Fair, and less than 70 as Poor. These categories provide an interpretation of score levels; they do not themselves report how participants in either arm scored.
As a general matter, a clinical score can describe a participant’s status in a structured way and can make follow-up results easier to interpret than an unstructured narrative alone. The registry’s description establishes that Harris Hip Score was selected as the primary measure, but it does not provide the score’s components, the scoring procedure, or details about how assessments were carried out. Those details are not reported in the registry record.
The record says the primary outcome population represents patients who returned for follow-up per protocol. It also states that no patients returned at the primary outcome time frame and that 0 patients were analyzed at 10 years. Therefore, no score distribution, group summary, or between-arm primary outcome estimate is available for that time point. The categories can explain what scores would mean if observed, but they cannot substitute for missing endpoint observations.
Harris Hip Score Pain is listed as a secondary outcome. The registry does not provide a result for that measure in the registry record reported for this trial. The endpoint descriptions thus identify what was intended to be assessed, while the available primary endpoint information establishes that the planned long-term score was not observed in an analyzed population.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The central interpretive fact is that the primary outcome was not analyzed at its stated time point. The registry identifies Harris Hip Score at 10 Years Post-Operative as the primary endpoint, then explains that no patients returned at that time and that 0 patients were analyzed. No group-level score, contrast between the cement groups, confidence interval, or inferential test for this endpoint is reported in the registry record. The intended primary question therefore cannot be answered from the posted primary outcome information.
The registry lists an enrollment of 400, but that overall figure cannot be used as a substitute for the number assessed at the endpoint. Enrollment and follow-up at a particular time point are different quantities. The record explicitly indicates that the analyzed population at the primary time point was empty. It does not describe the number of participants who returned at earlier follow-up visits, nor does it give a participant flow account that would explain follow-up over time.
The safety information is distinct from the missing primary efficacy outcome. The registry lists 202 participants at risk in the Answer Stem Utilizing Simplex Cement group and 200 in the Answer Stem Utilizing Palacos Cement group for serious events. Serious events affected 15 and 8 participants, respectively. Other events affected 0 participants in each listed group. These are descriptive counts in the registry record; they are not an adjusted comparison and do not establish that any difference is attributable to cement choice. The listed percentages for serious event terms are not identified by arm in the registry record reported, so they should not be assigned to either group.
Because allocation was non-randomized, the groups should not be treated as randomized controls. A descriptive contrast between groups, even if one were reported, could be influenced by differences in patient characteristics or clinical circumstances. The record does not report how participants came to receive each cement, whether the groups were comparable at baseline, or whether an adjusted analysis was conducted. It lists zero analyses.
There are no reported estimates of uncertainty or hypothesis tests for the primary score. General statistical interpretation relies on estimates and their uncertainty to distinguish what the observed data support from what remains imprecise. In this case, the lack of analyzed primary endpoint observations is more fundamental than imprecision: there is no primary endpoint estimate to interpret. The record supports a description of study design, endpoint intent, and the posted safety counts, but it does not support a conclusion about a long-term Harris Hip Score difference between the arms.
9. Statistical Methods Explained
What does the design allow?
The registry lists a parallel design, non-randomized allocation, and no masking. In a parallel design, participants are followed in one of the study arms rather than being described as crossing between the arms. That is a general explanation of the design label; the record does not give participant-level histories or report changes in assigned treatment. Non-randomized allocation means the registry does not describe chance assignment. In general, randomization can help balance measured and unmeasured characteristics across arms, while a non-randomized comparison can retain differences between the groups. Here, the method used to choose cement is not reported in the registry record, so the extent and direction of any group differences cannot be assessed from the design entry alone.
No masking is recorded. In general, masking can reduce the influence of treatment knowledge on assessments or reporting, depending on who is masked and how outcomes are measured. The record does not explain which people knew the treatment, whether outcome assessors were masked, or what procedures were used to limit assessment bias. Those details are not reported in the registry record.
What is the primary endpoint?
The primary endpoint is Harris Hip Score at 10 Years Post-Operative, with the score described on a 0-to-100 range and categorized as Excellent, Good, Fair, or Poor using the registry’s stated boundaries. In general, a continuous score retains gradations across its range, whereas categories group different values into broader bands. Reporting either form requires actual observations and a clear description of the summary method. The record supplies the interpretive bands but no analyzed score values, mean, median, distribution, or category counts at the primary time point.
The registry says that no patients returned at the primary outcome time frame and that 0 patients were analyzed. That prevents estimation of the primary outcome at the stated time point. A confidence interval describes the uncertainty around an estimated quantity; it cannot be meaningfully attached to an endpoint estimate when no participants were analyzed and no estimate is reported. Likewise, a p-value would address a specified statistical comparison, but the registry reports no primary endpoint test or p-value. Neither should be inferred from the enrollment figure or from the safety counts.
How should the allocation be considered?
For a randomized comparison, the assigned groups are formed by a chance mechanism specified by the study. This registry instead lists non-randomized allocation. General statistical adjustment can sometimes address observed differences when appropriate variables and a prespecified model are available, but it cannot be assumed to remove all bias. The registry record does not report a baseline comparison, adjustment variables, model specification, or adjusted outcome estimate. It lists zero analyses. Accordingly, no adjusted treatment contrast can be reconstructed or described.
The two arms name the same Answer® hip stem with different bone cement. That gives a clear descriptive distinction between the arms, but it does not establish that cement was the only difference in care or in participant characteristics. Details needed to assess that question are not reported in the registry record. The study’s broader purpose mentions the acetabular shell as well as the stem and cement, while the posted arm descriptions distinguish the cement used with the stem. No additional device-specific outcome analysis is reported in the registry record.
What do the event counts mean?
The serious event information gives participants at risk and participants affected in each arm, and also gives counts for other events. These are descriptive safety data. In general, a count is easier to interpret when its event definition, observation period, and denominator are clear. The record lists at-risk counts of 202 and 200 and serious-event counts of 15 and 8, but the registry entries do not describe the event collection window, adjudication method, or whether participants could contribute more than one event. The record also lists 0 participants affected by other events in each arm. The deaths fields have no reported counts. These details should not be filled in by assumption.
The registry separately lists serious event terms with percentages. General interpretation of a percentage depends on knowing its denominator and whether it counts participants, events, or another quantity. The registry entries do not identify the denominator for those listed percentages or attribute the terms to a particular arm. Therefore, the term percentages should be read as registry-listed descriptive information, not as arm-specific estimates or a comparative analysis.
What is the role of planning calculations?
The record describes a sample-size planning illustration based on an observed effect, with a two-sided significance level of 0.05, equal allocation, and a normal approximation. It says the effect to detect is a stated fraction of the observed effect, and explains that time-to-event calculations use total events while other calculations use participants per arm. Such calculations are planning illustrations, not observed outcomes or evidence that a study had a particular probability of detecting an effect. The registry does not report its own sample-size justification or establish that these illustration assumptions were the original design assumptions. The enrollment figure should not be treated as evidence of observed power.
General statistical planning asks what effect and precision a study is designed to evaluate, alongside assumptions about variability and analysis. Those design choices are not reported in the registry record. No power value, calculated sample-size result, or test of the primary outcome is stated in the trial details. Because the endpoint had no analyzed participants at its intended time point, planning illustrations cannot supply the missing clinical observations or make the primary comparison estimable.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists a primary Harris Hip Score outcome and a secondary Harris Hip Score Pain outcome, with two outcome measures in total. It reports zero analyses. The record does not state whether statistical hypotheses were tested, whether an analysis hierarchy was prespecified, or how any multiplicity from assessing more than one outcome would have been handled. Those matters are not reported in the registry record. Without reported tests or estimates, there is no basis for describing a multiplicity adjustment or interpreting nominal significance across outcomes.
Missing follow-up is decisive for the primary endpoint. The registry says that no patients returned at 10 Years Post-Operative and that 0 patients were analyzed. It does not describe the reasons participants did not return, the amount of missing information at earlier visits, or whether other follow-up data were used. The reason for missingness and the method used to handle missing values are not reported in the registry record. No imputation procedure, sensitivity analysis, or alternative follow-up analysis is described.
In general, missing outcome data can limit interpretation because the observed participants may not represent all enrolled participants. Statistical methods can address missingness only under assumptions and with information appropriate to the problem; they do not turn absent observations into directly observed outcomes. Here, no primary endpoint observations were analyzed at the stated time point, and the record does not report an alternative analysis that estimates the 10-year score.
The primary outcome description defines the intended follow-up population as patients who returned per protocol, but does not provide a broader analysis-population definition. The record does not report whether analyses were intended to include all enrolled participants, only those receiving a particular cement, or another population. It also does not report a participant flow account by arm or a reason for termination. These omissions constrain interpretation of both follow-up and the scope of any intended analysis.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| Answer Stem Utilizing Simplex Cement | 15 | 202 | 7.4% |
| Answer Stem Utilizing Palacos Cement | 8 | 200 | 4.0% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 5% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Answer Stem Utilizing Simplex Cement | 0 of 202 |
| Answer Stem Utilizing Palacos Cement | 0 of 200 |
Most frequent serious adverse event terms
| Event term | Organ system | Answer Stem Utilizing Simplex Cement | Answer Stem Utilizing Palacos Cement |
|---|---|---|---|
| Dislocation | Musculoskeletal and connective tissue disorders | 9 of 202 | 1 of 200 |
| Deep infection < 6 weeks | Infections and infestations | 1 of 202 | 2 of 200 |
| Femoral loosening | Musculoskeletal and connective tissue disorders | 2 of 202 | 0 of 200 |
| Deep infection > 6 weeks | Infections and infestations | 1 of 202 | 1 of 200 |
| Revision with all components removed and re-implantation | Surgical and medical procedures | 0 of 202 | 2 of 200 |
| Myocardial infarction | Cardiac disorders | 1 of 202 | 0 of 200 |
| Stroke | Vascular disorders | 1 of 202 | 0 of 200 |
| Femoral, acetabular loosening and instability | Musculoskeletal and connective tissue disorders | 0 of 202 | 1 of 200 |
| I&D, exchange of poly liner | Surgical and medical procedures | 0 of 202 | 1 of 200 |
Serious events with the highest arm-level rate: dislocation (4.5%), deep infection < 6 weeks (1.0%), revision with all components removed and re-implantation (1.0%), femoral loosening (1.0%), deep infection > 6 weeks (0.5%).
The registry lists serious adverse event counts separately for the two arms. For Answer Stem Utilizing Simplex Cement, 202 participants were at risk and 15 were affected by serious events. For Answer Stem Utilizing Palacos Cement, 200 were at risk and 8 were affected. Other events affected 0 participants in each group. These are posted counts, not estimates adjusted for differences between the arms. Because allocation was non-randomized, a simple descriptive contrast cannot establish that cement caused any difference.
The registry also lists serious event terms with percentages: Dislocation, 4.5%; Deep infection < 6 weeks, 1.0%; Revision with all components removed and re-implantation, 1.0%; Femoral loosening, 1.0%; Deep infection > 6 weeks, 0.5%; and Femoral, acetabular loosening and instability, 0.5%. The registry entries do not specify the denominators for these percentages or identify the arm associated with each term. They therefore should not be interpreted as arm-specific rates or used to compare the cement groups.
The record does not give a serious-event observation period, event definition details, or a count of deaths. The event counts should be read within those limits. They describe what the registry lists, but do not by themselves establish a causal relationship, a difference in risk, or the completeness of safety follow-up.
12. What the Result Does, and Does Not, Mean
The record establishes that a clinical outcomes study was registered for total hip replacement using the Answer® hip stem with Simplex or Palacos bone cement. It identifies a parallel, non-randomized design and no masking. It also records the study’s primary outcome as Harris Hip Score at 10 Years Post-Operative and describes the score’s range and interpretive categories. Those details clarify the intended question and the context in which a score could be read.
The record does not provide the primary endpoint result. It states that no patients returned at the primary outcome time frame and that 0 patients were analyzed at 10 years. There is therefore no basis in the posted primary outcome information for estimating a score in either arm or assessing a long-term difference between them. The registry’s enrollment figure does not alter that limitation, because it is not a count of participants analyzed at the primary time point.
The serious event counts are available as descriptive information, but they are not a randomized comparison. Non-randomized allocation can leave differences between groups that make simple comparisons difficult to interpret. The event-term percentages also lack a reported denominator and arm attribution in the registry record, so they do not support group-specific interpretation. No adjustment, inferential analysis, or comparative estimate is reported.
In general, a registry result is most informative when the planned question, analyzed population, outcome estimates, and uncertainty are all described. For this study, the registry provides design and safety details but not an analyzed long-term primary outcome. The status is terminated, but the reason is not reported in the registry record. The record does not state whether early outcomes were analyzed elsewhere in the registry information covered by these registry entries or whether a different endpoint was used to inform conclusions.
Accordingly, the appropriate reading is limited: the intended long-term outcome is clear, but its result is unavailable; the safety counts can be described, but not used as causal evidence; and the non-randomized design does not support treating the arms as equivalent to randomized controls. The registry entries do not establish whether either cement choice changes Harris Hip Score or safety outcomes.
13. Why This Trial Matters Statistically
This trial is statistically informative in part because it illustrates the difference between a planned endpoint and an analyzed endpoint. Harris Hip Score at 10 Years Post-Operative is clearly identified as primary, and the registry defines the score’s range and categories. Yet the record also states that nobody returned at that time point and that 0 patients were analyzed. A well-described outcome scale cannot answer a clinical question without observations at the relevant time point.
The distinction between enrollment and follow-up is important. The registry lists enrollment of 400, but that figure does not show how many participants contributed an outcome at a particular visit. The explicit zero analyzed at the primary time point makes clear why enrollment alone cannot be used to infer the availability of long-term data. General statistical methods can summarize observations and quantify uncertainty; they cannot recover an outcome that was not observed or reported without additional assumptions and information.
The design also highlights why allocation matters when interpreting comparisons. The registry identifies non-randomized allocation, so differences between arms cannot automatically be attributed to cement choice. A group contrast may reflect selection or other differences, and the record does not report an adjusted analysis that addresses such concerns. This is particularly relevant when the main intended endpoint is unavailable and the remaining posted outcome information is descriptive safety counting.
The safety details illustrate a further interpretive issue: counts, denominators, event-term percentages, and event definitions need to be considered together. The record provides some group counts, but does not explain the period of observation or identify the denominator and arm attribution for the listed term percentages. The entries can be reported faithfully, while the limits on comparing them remain explicit.
Finally, the registry’s status of terminated does not explain why the study ended. That reason is not reported in the registry record. Distinguishing known details from unreported design and analysis details is central to responsible biostatistical interpretation. In this case, the most important statistical conclusion is about the limits of what can be estimated, not a treatment-effect finding.
14. Limitations
- The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
- Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.
The most direct limitation is the absence of analyzed observations for the primary endpoint at 10 Years Post-Operative. The registry explicitly states that no patients returned at that time and that 0 patients were analyzed. No primary Harris Hip Score estimate, group comparison, measure of uncertainty, or test is reported. This prevents interpretation of the intended long-term primary question.
The non-randomized allocation limits causal interpretation. The registry does not explain how cement choice was determined, whether the groups differed at baseline, or whether any adjustment was made. It lists zero analyses. Thus, the posted serious event counts should not be treated as estimates of a causal effect of cement type, and the record does not provide an adjusted comparison to address potential group differences.
The registry does not report the reasons for missing follow-up, participant flow by arm, or a method for handling missing outcomes. It also does not state whether the listed enrollment represents the number enrolled, the number assigned to arms, or the number with data at other visits beyond the enrollment entry. These details are not reported in the registry record. The record’s terminated status is given without a reason.
Safety reporting is also limited by missing context. The period over which events were collected, the event ascertainment procedures, and the deaths count are not reported. The serious event terms and percentages are listed without a denominator or arm attribution in the registry record. Therefore, those percentages cannot be read as arm-specific rates.
Finally, the registry does not report the statistical analysis plan, sample-size justification, analysis population definitions, or multiplicity procedures. The planning illustration described in the record is not the trial’s own stated design justification. These limitations mean that the registry supports a restricted descriptive account rather than a full evaluation of efficacy or comparative safety.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Total Hip Replacement With the Answer® Hip Stem and Ranawat/Burnstein® Shell Using Simplex® or Palacos® Bone Cement — NCT00588861.
- Registry record last updated 2017-01-27; status last verified 2012-01.
- Results first posted 2012-01-26.
- Data retrieved from ClinicalTrials.gov on 2026-11-09.
- Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.
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18. Record Summary
The registry record describes a terminated, parallel, non-randomized study with no masking. Its purpose was to document clinical outcomes for devices used in total hip replacement, including the Answer® hip stem, the Ranawat/Burnstein® acetabular shell, and Simplex® or Palacos® bone cement. The two arm descriptions distinguish the Answer® hip stem used with Simplex cement from the same stem used with Palacos cement. The registry lists enrollment of 400, a start date of 2002-09, and primary completion on 2010-05.
The primary outcome was Harris Hip Score at 10 Years Post-Operative. The registry describes its 0-to-100 range and score categories, but states that no patients returned at the primary outcome time frame and that 0 patients were analyzed. Harris Hip Score Pain is listed as a secondary outcome. The registry lists serious event counts of 15 among 202 at risk in the Simplex group and 8 among 200 at risk in the Palacos group; other events affected 0 participants in each group. It lists two outcome measures and zero analyses. The reason for termination and the detailed statistical plan are not reported in the registry record.