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1.

Background

Although most hip dislocations occur in either standing or sitting position, the safe zone for implant position is defined for the supine position. Our goal was to determine preoperative and postoperative pelvis and hip orientations and whether the safe zone defined in supine position can be used to assess standing radiographs.

Methods

Preoperative and postoperative three-dimensional EOS images were assessed in 66 total hip arthroplasty patients. None of the patients had dislocation within the follow-up period (12-36 months). The acetabular anteversion (both anterior pelvic plane [APP] and patient functional plane) and the femoral anteversion were measured. The sacral slope, pelvic version, pelvic inclination, and pelvic incidence were also measured.

Results

Acetabular anteversion increased postoperatively in both APP and patient functional plane (P <.001). Femoral neck anteversion decreased postoperatively (P =.0942). Sacral slope was 42.4° (?25.9° to 24°) preoperatively compared with 40.3° (?4.1° to 64.2°) postoperatively (P =.013). Pelvic version changed from 15.2° (?10.4° to 43.8°) to 17.2° (?6° to 46.7°; P = 0.008). Pelvic inclination was 1.12° (?25.9° to 24°) before total hip arthroplasty and ?1.2° (?40.7° to 23.4°) postoperatively (P =.005).

Conclusion

The acetabular and femoral implant orientations in standing position reside out of the safe zone in most patients. The APP is not vertical in standing position in most patients due to anterior or posterior pelvic tilt. The proposed safe zone in supine position may not be a useful measure in the assessment of standing radiographs of patients with significant anterior or posterior pelvic tilt.

Level of Evidence

Level IV, therapeutic case series study.  相似文献   

2.

Background

The purpose of the study was to evaluate the implant positions and clinical results of revision total hip arthroplasty (THA) using an imageless navigation with the concept of combined anteversion.

Methods

A total of 40 cementless revision THAs (24 men and 16 women) using an imageless navigation with the concept of combined anteversion were retrospectively evaluated. The concept of combined anteversion was applied in cup positioning based on Widmer's equation (cup anteversion + 0.7 × stem anteversion). The mean follow-up period was 80.7 months. Postoperatively, the inclination of the cup was evaluated on standard anteroposterior view of the radiograph, and the anteversion of the cup and femoral stem was evaluated using computed tomography scan. A cup inclination of 40° ± 10° and combined anteversion of the cup and femoral stem of 37° ± 10° based on Widmer's equation were regarded as the “safe zone.”

Results

The average anteversion of the revised femoral stems was 15.3° ± 2.9° (range, 9.5°-21.5°), whereas that of the remained femoral stems was 17.4° ± 9.7° (range, 4.2°-29.8°). The inclination, anteversion of the cup, and combined anteversion after revision THA were 42.3° ± 3.1° (range, 32.1°-48.2°), 25.0° ± 2.9° (range, 16.9°-29.5°), and 36.1° ± 3.4° (range, 27.2°-42.9°), respectively. Therefore, the position of the implants, relative to the safe zone, showed no outliers after the revision surgery. Neither dislocation nor osteolysis was observed after the surgery.

Conclusion

Favorable results of this study indicate that imageless navigation helps the surgeon in placing the components of revision THA in the safe zone. This study also shows that when this safe zone is consistently obtained, then no postoperative dislocations were observed in these patients over the 6-year follow-up period.  相似文献   

3.

Background

Recently, the importance of acetabular component positioning in the Lewinnek “safe zone” in preventing prosthetic dislocation following total hip arthroplasty (THA) has been questioned. The purpose of this study was to determine the proportion of acetabular components within the Lewinnek safe zone between primary and revision THAs that have sustained a dislocation vs matched controls without a dislocation event.

Methods

This was a retrospective, institutional review board–approved investigation of THAs performed at our institution or referred to our institution between 1997 and 2013. Ninety-six primary THAs and 60 revision THAs that sustained a dislocation were included and matched 1:1 based on age, gender, and body mass index with nondislocated controls. Acetabular component inclination and anteversion were performed using Martell Hip Analysis Suite and compared between the 2 cohorts for both primary and revision THAs.

Results

The proportion of acetabular components within the safe zone for both inclination and anteversion was 23 of 96 (24%) in primary THA dislocators vs 48 of 96 (50%, P < .001) in controls. The proportion of acetabular components within the safe zone for both inclination and anteversion was 28 of 60 (47%) in revision THA dislocators vs 40 of 60 (66%, P = .03) in controls.

Conclusion

Patients sustaining a dislocation following a primary or revision THA had acetabular components less frequently positioned within the safe zone compared to control patients. This study suggests acetabular component positioning remains an important variable in decreasing the risk of dislocation following primary and revision THA.  相似文献   

4.

Background

The rate of and the reasons for the failure of metal-on-metal (MoM) bearings have recently been discussed in literature. The aim of this study was to evaluate the influence of acetabular cup inclination and version angles on revision risk in patients with MoM hip arthroplasty.

Methods

We retrospectively reviewed 825 patients (976 hips) who underwent a MoM hip arthroplasty between 2000 and 2013. There were 474 men and 351 women, with a mean age of 58 (19-86) years. Acceptable cup orientation was considered to be inside the Lewinnek's safe zone.

Results

The mean acetabular inclination angle was 48.9° (standard deviation, 8.1°; range, 16°-76°) and version angle 20.6° (standard deviation, 9.9°; range, ?25 to 46°). The cup was found to be outside the Lewinnek's safe zone in 571 hips (58.5%). Acetabular cup revision surgery was performed in 157 hips (16.1%). The cup angles were outside Lewinnek's safe zone in 69.2% of the revised hips. The mean interobserver reliability and intraobserver repeatability of the measurements of cup inclination and version angles were excellent (intraclass correlation coefficients >0.90). The odds ratio for revision in hips outside vs inside the Lewinnek's safe zone was 1.82 (95% confidence interval, 1.26-2.62; P = .0014).

Conclusion

Our findings provide compelling evidence that a cup position outside the Lewinnek's safe zone is associated with increased revision risk in patients with MoM arthroplasty.  相似文献   

5.

Background

This study compares the differences in acetabular component position, leg length discrepancy, and hip offset between the anterior and posterior approach. A novel method is applied to determine the acetabular anteversion using the C-arm tilt angle for the anterior approach.

Methods

Hundred consecutive anterior total hip arthroplasties were matched according to gender, body mass index, and age to a cohort of 100 primary total hip arthroplasties operated on through a posterior approach. Postoperative radiographs were analyzed to determine cup inclination, cup anteversion, leg length discrepancy, and hip offset.

Results

The mean inclination was 40.8° (range 33°-48°) and 45.1° (range 33°-55°) for the anterior and posterior approach, respectively. Using the new C-arm tilt plane technique, an average acetabular anteversion of 18.4° (range 11°-26°) was achieved with the anterior approach compared with 23.6° (range 8°-38°) with the posterior approach. Hundred percent cups in the anterior group and 81% in the posterior group fell within the safe zone (P < .001). There was no difference in the overall hip offset between the operated side and the contralateral side for the anterior (P = .074) and posterior (P = .919) group. There was no difference in leg length discrepancy between the 2 approaches (P = .259).

Conclusion

Intraoperative fluoroscopy-assisted direct anterior approach was associated with improved acetabular component positioning. However, no benefit was shown with regards to restoration of hip offset or leg length.  相似文献   

6.

Background

Acetabulum positioning affects dislocation rates, component impingement, bearing surface wear rates, and need for revision surgery. Novel techniques purport to improve the accuracy and precision of acetabular component position, but may have a significant learning curve. Our aim was to assess whether adopting robotic or fluoroscopic techniques improve acetabulum positioning compared to manual total hip arthroplasty (THA) during the learning curve.

Methods

Three types of THAs were compared in this retrospective cohort: (1) the first 100 fluoroscopically guided direct anterior THAs (fluoroscopic anterior [FA]) done by a surgeon learning the anterior approach, (2) the first 100 robotic-assisted posterior THAs done by a surgeon learning robotic-assisted surgery (robotic posterior [RP]), and (3) the last 100 manual posterior (MP) THAs done by each surgeon (200 THAs) before adoption of novel techniques. Component position was measured on plain radiographs. Radiographic measurements were taken by 2 blinded observers. The percentage of hips within the surgeons’ “target zone” (inclination, 30°-50°; anteversion, 10°-30°) was calculated, along with the percentage within the “safe zone” of Lewinnek (inclination, 30°-50°; anteversion, 5°-25°) and Callanan (inclination, 30°-45°; anteversion, 5°-25°). Relative risk (RR) and absolute risk reduction (ARR) were calculated. Variances (square of the standard deviations) were used to describe the variability of cup position.

Results

Seventy-six percentage of MP THAs were within the surgeons’ target zone compared with 84% of FA THAs and 97% of RP THAs. This difference was statistically significant, associated with a RR reduction of 87% (RR, 0.13 [0.04-0.40]; P < .01; ARR, 21%; number needed to treat, 5) for RP compared to MP THAs. Compared to FA THAs, RP THAs were associated with a RR reduction of 81% (RR, 0.19 [0.06-0.62]; P < .01; ARR, 13%; number needed to treat, 8). Variances were lower for acetabulum inclination and anteversion in RP THAs (14.0 and 19.5) as compared to the MP (37.5 and 56.3) and FA (24.5 and 54.6) groups. These differences were statistically significant (P < .01).

Conclusion

Adoption of robotic techniques delivers significant and immediate improvement in the precision of acetabular component positioning during the learning curve. While fluoroscopy has been shown to be beneficial with experience, a learning curve exists before precision improves significantly.  相似文献   

7.

Background

Cup anteversion and inclination are important for avoiding implant impingement and dislocation in total hip arthroplasty. However, functional cup anteversion and cup inclination also change as the pelvic sagittal inclination (PSI) changes. Therefore, PSI in both supine and standing positions was measured in a large cohort in this study.

Methods

A total of 422 patients (median age, 61; range, 15-87) who underwent total hip arthroplasty were the subjects of this study. There were 83 patients with primary osteoarthritis (OA), 274 patients with developmental dysplasia–derived secondary OA, 48 patients with osteonecrosis, and 17 patients with rapidly destructive coxopathy (RDC). Preoperative PSI in supine and standing positions was measured by automated computed topography segmentation and landmark localization of the pelvis followed by intensity-based 2D-3D registration, and the number of cases in which PSI changed more than 10° posteriorly was calculated. Hip disease, sex, and age were analyzed if they were related to a PSI change of more than 10°.

Results

The median PSI was 5.1° (interquartile range, 0.4°-9.4°) in supine and ?1.3° (interquartile range, ?6.5° to 4.2°) in standing position. There were 79 cases (19%) in which the PSI changed more than 10° posteriorly from supine to standing. Elder age and patients with primary OA and RDC were revealed to be the related factors.

Conclusion

PSI changed more than 10° posteriorly from supine to standing in 19% of cases. Age and diagnosis of primary OA and RDC were the significant factors for the posterior rotation.  相似文献   

8.

Background

The acetabular component orientation in total hip arthroplasty (THA) is of critical importance to the good clinical results. However, traditional widely used cup alignment guides for cup placement are reported to be relatively unreliable. The present study aims at comparing a novel cup alignment guide, which can be attached to our anatomical pelvic plane (APP) pelvic lateral positioner for reducing discrepancies in sagittal pelvic tilt and indicate a targeted cup angle based on the APP, with a conventional cup alignment guide.

Methods

The subjects were 136 hips of 136 patients who underwent unilateral THA using the APP positioner. The procedure was performed with the conventional cup alignment guide (conventional group; 60 hips) and with the novel cup navigator (mechanical navigator group; 76 hips). Postoperative cup angles and discrepancies of postoperative cup angles (inclination and anteversion angles) from the targeted angles were compared between the 2 groups to evaluate the usefulness of these navigators.

Results

The mean cup angles in the conventional group were 39.0° ± 5.3° for the inclination angle and 21.7° ± 6.4° for the anteversion angle, whereas those in the mechanical navigator group were 40.6° ± 3.2° and 18.3° ± 4.6°, respectively (P = .018, P < .0001). The discrepancies from the targeted angles were 3.5° ± 3.1° for the inclination angle and 4.6° ± 3.4° for the anteversion angle in the conventional group and 2.3° ± 2.3° and 3.2° ± 2.7°, respectively, in the mechanical navigator group (P = .020, P = .012).

Conclusion

The mechanical cup navigator easily attachable to the APP positioner is a tool that can improve the accuracy of cup placement in a simple, economical, and noninvasive manner in THA via the lateral position.  相似文献   

9.

Background

This study used EOS imaging of primary total hip arthroplasty (THA) patients, with and without predating spinal fusion, to investigate (1) the impact of spinal fusion on acetabular implant anteversion and inclination, and (2) whether more extensive spinal fusion (fusion starting above the thoracolumbar junction or extension of fusion to the sacrum) affects acetabular implant orientation differently than lumbar only spinal fusion.

Methods

Ninety-three patients had spinal fusion (case group), and 150 patients were without spinal fusion (controls). None of the patients experienced dislocation. The change in sacral slope (SS) and cup orientation from standing to sitting was measured.

Results

Mean SS change from the standing to sitting positions was ?7.9°in the fusion group vs ?18.4°in controls (P = .0001). Mean change in cup inclination from the standing to sitting positions was 4.9°in the fusion group vs 10.2°in controls (P = .0001). Mean change in cup anteversion from standing to sitting positions was 7.1°in the fusion group vs 12.1°in controls (P = .0001). For each additional level of spinal fusion, the change in SS from standing to sitting positions decreased by 1.6(95% confidence interval [CI], 2.2073-1.0741), the change in cup inclination decreased by 0.8(95% CI, 0.380-1.203), and the change in cup anteversion decreased by 0.9(95% CI, 0.518-1.352; P < .001 in all cases).

Conclusion

Patients with spinal fusion demonstrated less adaptability of the lumbosacral junction. Longer spinal fusion or inclusion of the pelvis in the fusion critically impacts hip-spine biomechanics and significantly affects the ability to compensate in the standing-to-sitting transition.  相似文献   

10.

Background

Obesity has been described as an independent risk factor for acetabular component malpositioning. The purpose of this study was to determine if this could be overcome by use of fluoroscopic navigation in total hip arthroplasty (THA).

Methods

The first, postoperative, standing, anteroposterior pelvis radiographs from 1599 consecutive patients who underwent fluoroscopic-guided THAs via anterior approach during a six-year period were obtained. We retrospectively reviewed this prospectively collected data. Inclination and anteversion were measured as described by Barrack et al. Intraoperative target ranges for inclination and anteversion angles were 30°-50° and 5°-25°. Patients were divided into 3 cohorts by body mass index, nonobese (<30 kg/m2) obese (between 30 and 40 kg/m2) and morbidly obese (>40 kg/m2), looking for significant differences in acetabular component positioning.

Results

Of the 1599 patients, 1065 were nonobese, 506 obese, and 28 morbidly obese. Overall, average inclination was 37.7° and anteversion was 16.3°. Regarding inclination, 95.0% of cups were positioned in the safe zone, 95.7% for anteversion, and 91.2% for both inclination and anteversion. Analysis of each cohort individually revealed an average inclination of 37.5° in the nonobese, 37.9° in the obese, and 39.9° in the morbidly obese patients. For anteversion, each group's averages were 16.1°, 16.5°, and 16.0°, respectively. There was no significant relationship between a patient's body mass index and cup position for inclination (P = .867), anteversion (P = .673), or both inclination and anteversion (P = .624).

Conclusion

Fluoroscopy is a useful tool for achieving a targeted acetabular component orientation in direct anterior THA, irrespective of patient BMI.  相似文献   

11.

Background

Accurate cup positioning is one of the most challenging aspects of total hip arthroplasty (THA). Undetected movement of the patient during THA surgery can lead to inaccuracies in cup anteversion and inclination, increasing the potential for dislocation and revision surgery. Investigations into the magnitude of patient motion during THA are not well represented in the literature.

Methods

We analyzed intraoperative pelvic motion using a novel navigation device used to assist surgeons with cup position, leg length, and offset during THA. This device uses an integrated accelerometer to measure motion in 2 orthogonal degrees of freedom. We reviewed the data from 99 cases completed between February and September 2016.

Results

The mean amount of pitch recorded per patient was 2.7° (standard deviation, 2.2; range, 0.1°-9.9°), whereas mean roll per patient was 7.3° (standard deviation, 5.5; range, 0.3°-31.3°). Twenty-one percent (21 of 99) of patients demonstrated pitch of >4°. Sixty-nine percent (68 of 99) of patients demonstrated >4° of roll, and 25% (25 of 99) of patients demonstrated roll of ≥10°.

Conclusion

Our findings indicate that while the majority of intraoperative motion is <4°, many patients experience significant roll, with a large proportion rolling >10°. This degree of movement has implications for acetabular cup position, as failure to compensate for this motion can result in placement of the cup outside the planned safe zone, thus, increasing the potential for dislocation. Further study is warranted to determine the effect of this motion on cup position, leg length, and offset.  相似文献   

12.

Background

To our knowledge, no study has assessed the ability of rigid patient positioning devices to afford arthroplasty surgeons with ideal acetabular orientation throughout surgery. The purpose of this study is to use robotic arm–assisted computer navigation to assess the reliability of pelvic position in total hip arthroplasty performed on patients positioned with rigid positioning devices.

Methods

A prospective cohort of 100 hips (94 patients) underwent robotic-guided total hip arthroplasty in the lateral decubitus position from the posterior approach, 77 stabilized by universal lateral positioner, and 23 by peg board. Before reaming, computed tomography–templated computer software generated true values of pelvic anteversion and inclination based on the position of the robot arm registered to the patient’s preoperative pelvic computed tomography.

Results

Mean alteration in anteversion and inclination values was 1.7° (absolute value, 5.3°; range, ?20° to 20°) and 1.6° (absolute value, 2.6°; range, ?8° to 10°), respectively. And 22% of anteversion values were altered by >10° and 41% by >5°. There was no difference between hip positioners used (P = .36). Anteversion variability was correlated with body mass index (P = .02).

Conclusion

Despite the use of rigid patient positioning devices—a lateral hip positioner or peg board—this study reveals clinically important malposition of the pelvis in many cases, especially with regard to anteversion. These results show a clear need to pay particular attention to anatomic landmarks or computer-assisted techniques to assure accurate acetabular cup positioning. Patient positioning should not be solely trusted.  相似文献   

13.

Background

Changes in spinal alignment and pelvic tilt alter acetabular orientation in predictable ways, which may have implications on stability of total hip arthroplasty (THA). Patients with sagittal spinal deformity represent a subset of patients who may be at particularly high risk of THA instability because of postural compensation for abnormal spinal alignment.

Methods

Using standing stereoradiography, we evaluated the spinopelvic parameters, acetabular cup anteversion, and inclination of 139 THAs in 107 patients with sagittal spinal deformity. Standing images were compared with supine pelvic radiographs to evaluate dynamic changes in acetabular cup position. Dislocation and revision rates were procured through retrospective chart review. The spinal parameters and acetabular cup positions among dislocators were compared with those who did not dislocate.

Results

The rate of THA dislocation in this cohort was 8.0%, with a revision rate of 5.8% for instability. Patients who sustained dislocations had significantly higher spinopelvic tilt, T1-pelvic angle, and mismatch of lumbar lordosis and pelvic incidence. Among all patients, 78% had safe anteversion while supine, which decreased significantly to 58% when standing due to increases in spinopelvic tilt. Among dislocating THA, 80% had safe anteversion, 80% had safe inclination, and 60% had both parameters within the safe zone.

Conclusion

In this cohort, patients with THA and concomitant spinal deformity have a particularly high rate of THA instability despite having an acetabular cup position traditionally thought of as within acceptable alignment. This dislocation risk may be driven by the degree of spinal deformity and by spinopelvic compensation. Surgeons should anticipate potential instability after hip arthroplasty and adjust their surgical plan accordingly.  相似文献   

14.

Background

Hip dislocation is one of the most common postoperative complications after total hip arthroplasty (THA). Potential contributors include patient- and surgical-related factors. We performed a retrospective cohort study to identify risk factors for postoperative dislocation in patients receiving THA via the posterolateral approach.

Methods

We assessed 1326 consecutive primary THAs performed between 2010 and 2015. Patient information was documented, and plain radiographic films were used to evaluate cup positioning, hip offset, and hip length change. A multiple logistic regression was used to identify risk factors for dislocation. Follow-up was coordinated by the Danish National Patient Registry.

Results

Age and American Society of Anesthesiologists scores were higher in dislocating THA compared with those in the nondislocating THA. Cup anteversion was less in dislocating THA compared with that in nondislocating THA. Independent risk factors for cup dislocation were increased age, body mass index <25 and >30 kg/m2, and leg shortening of >5 mm.

Conclusion

Surgeons should aim for a shortening of leg length <5 mm to reduce the risk of postoperative dislocation in primary THA. Although anteversion was reduced for dislocating THA, there is likely no universal safe zone for cup positioning. Hip stability is multifactorial, and optimal cup positioning may vary from patient to patient.  相似文献   

15.

Background

About 50%-70% of dislocators have cups placed within so-called “safe zones.” It has been postulated that factors such as femoral head size and pelvic tilt, obliquity, or rotation may influence postoperative stability. Therefore, we assessed varying degrees of pelvic tilt and head sizes on the range of motion (ROM) to impingement.

Methods

A hip simulator was used to import models of 10 subjects who performed object pickup, squatting, and low-chair rising. Parameters were set for pelvic tilt, stem version, and the specific motions as defined by the subjects. Femur-to-pelvis relative motions were determined for abduction/adduction, internal/external rotation, and flexion/extension. Varying tilt angles were tested. Thirty-two millimeter and 36-mm head with a standard cup and 42-mm dual mobility cup were tested. Cup orientations for abduction and anteversion combinations were chosen, and computations of minimum clearances or impingement between components were made.

Results

The ROM to impingement varied with the different pelvic tilts and femoral head sizes and with the different motions. The larger the head size, the larger the impingement-free ROM. Negative 10° of pelvic tilt led to the largest impingement-free zone, whereas 10° of forward tilt was associated with fewer impingement-free cup anteversion and abduction angle combinations. Variations in pelvic tilt had the greatest influence on object pickup and affected the impingement-free “safe zone.”

Conclusion

Targets for impingement-free motion may be smaller when considering varying pelvic tilts and femoral head sizes, particularly for certain activities, such as object pickup. These findings may indicate the need for more individualized patient planning.  相似文献   

16.

Background

Functional anteversion and inclination of the cup change as the pelvic sagittal inclination (PSI) changes. The purposes of this study were to investigate the chronological changes of PSI during a 10-year follow-up period after total hip arthroplasty (THA) and to report the characteristics of patients who showed a greater than 10° change in the PSI from the supine to the standing position.

Methods

The subjects were 70 patients who were followed up for 10 years after THA. PSI values in the supine and standing positions were measured by 2D-3D matching using computed tomography images and pelvic radiographs. PSI values before THA and 1, 5, and 10 years after THA were compared in both the supine and standing positions.

Results

Supine PSI showed less than 5° of change, whereas standing PSI showed a significant decrease with time over the 10-year period. Although 43% of patients with less than 10° of difference in the PSI between the supine and standing positions before THA increased PSI posteriorly (reclining) more than 10° in standing from the supine position at 10 years, no late dislocation was observed.

Conclusion

Supine PSI showed no significant change, but standing PSI showed a significant increase posteriorly with time over a 10-year period. However, this PSI change did not reach the level that it caused negative consequences such as late dislocation. The pelvic position in the supine position might still be a good functional reference position of the pelvis for aiming to achieve proper cup alignment at 10 years.  相似文献   

17.

Background

Studies that have previously examined the relationship between acetabular component inclination angle and polyethylene wear have shown increased wear of conventional polyethylene with high inclination angles. To date, there are no long-term in vivo studies examining the correlation between cup position and polyethylene wear with highly crosslinked polyethylene.

Methods

An institutional arthroplasty database was used to identify patients who had metal-on-highly crosslinked polyethylene primary total hip arthroplasty using the same component design with a minimum follow-up of 10 years. A modified radiostereometric analysis examination setup was utilized, recreating standard anteroposterior and cross-table lateral examinations in a single stereo radiostereometric analysis acquisition. The same radiographs were used to measure inclination angle and anteversion.

Results

A total of 43 hips were included for analysis in this study. Average follow-up was 12.3 ± 1.2 years. The average linear wear rate was calculated to be 0.066 ± 0.066 mm/y. Inclination angle was not correlated with polyethylene wear rate (P = .82). Anteversion was also not correlated with polyethylene wear rate (P = .11).

Conclusion

At long-term follow-up of >10 years, highly crosslinked polyethylene has a very low wear rate. This excellent tribology is independent of acetabular position. The low wear rate highlights the excellent results of metal on highly crosslinked polyethylene, and supports its use in total hip arthroplasty.  相似文献   

18.

Background

Controversy exists as to whether early functional outcomes differ after total hip arthroplasty performed using the direct anterior approach (DAA) or the posterolateral approach (PLA).

Methods

One hundred twenty patients were enrolled in this study and were divided into 2 groups based on surgical approach. Group A included patients who had a total hip arthroplasty with a DAA, whereas group B included those with a PLA. Patients were randomized into the DAA or PLA groups (n = 60), and perioperative and postoperative outcomes were recorded.

Results

When compared with the PLA, the DAA had a shorter incision length (9.1 vs 13.1 cm; P < .01), shorter hospital stay (2.8 vs 3.3 days, P = .04), and lower self-reported pain. Both serum inflammatory and muscle damage markers were lower in the DAA group. However, the PLA had shorter operative times (65.5 vs 83.3 min, P = .03) and less intraoperative blood loss (123.8 vs 165.9 mL, P = .04). The DAA had significantly lower variance in cup inclination and anteversion. Similar rates of intraoperative complications were identified in the 2 groups. The DAA was associated with better functional recovery at 3 months based on the Harris hip score, University of California Los Angeles activity score, and gait analysis; however, functional recovery at 6 months was similar between the 2 groups.

Conclusion

We found functional advantages in early recovery after the DAA compared with the PLA. The DAA can offer rapid functional recovery with less muscle damage, greater pain relief, and lower variance in cup inclination and anteversion. However, no functional difference was found at 6 months follow-up.  相似文献   

19.

Background

Noise after ceramic-on-ceramic (CoC) total hip arthroplasty (THA) is a well-recognized problem. Computer navigation has been shown to achieve desired implant orientation. Our aim was (1) to compare the incidence of noise between navigated and conventional CoC THAs and (2) to determine the factors associated with noise.

Methods

All patients undergoing CoC THA between March 2009 and August 2012 were considered for this study. Information regarding hip noise was obtained via telephone or postal interview. A comparable cohort of patients in navigated and conventional groups was used to evaluate the incidence of noise.

Results

A total of 375 CoC THAs using the same implant (202 navigated and 173 conventional) were evaluated. Patients <65 years of age had significantly greater incidence of noise (22.4% vs 6.1%; P < .001). To ensure similarity, a subgroup of cohort <65 years and a 32-mm head size was used to compare the incidence of noise between the navigated (68 THAs) and conventional (118 THAs) groups. Overall incidence of noise was significantly greater in the conventional group (28%) as compared with the navigated group (10%; P = .005). The relative risk of noise for the conventional vs the navigated group was 2.7 (P = .01), and for squeaking was 1.9 (P = .2). Squeaking THAs had significantly lower cup anteversion (13.4° ± 5.2°) as compared with the silent THAs (17.6° ± 6.9°; P = .01).

Conclusion

Navigated CoC THAs were 2.7× less likely to have noise as compared with the conventional ones. Squeaking THAs had significantly lower cup anteversion as compared with the silent ones. Patients of age <65 years had significantly greater incidence of noise after CoC THA.  相似文献   

20.

Background

Assessing femoral version in orthopedic surgery is important for preoperative planning of total hip arthroplasty, especially for recognizing excessive anteversion or retroversion. The present study addressed the following: (1) Is the position of the lesser trochanter correlated to the femoral neck axis? (2) If so, may femoral version be assessed by means of plain pelvic radiographs?

Methods

Three-dimensional computed tomography scans of 60 patients undergoing minimally invasive cement-free total hip arthroplasty were retrospectively analyzed, particularly with regard to the relation between the femoral neck axis and the lesser trochanter, the femoral version, and the size of the projected lesser trochanter in different rotational positions. Based on linear regression, a biomathematical formula was developed to assess femoral anteversion on plain radiographs depending on the visible part of the lesser trochanter.

Results

The mean difference between the location of the lesser trochanter axis and the femoral neck axis was 43.3° ± 6.2°. Eighty-seven percent of patients (52 of 60) had a deviation of <10° from the mean value of 43.3°. By virtual rotation of the femur in steps of 10°, the visible part of the lesser trochanter linearly increased with anteversion of the femur: femoral version = (lesser trochanter size ? 5.57) × 4.17. There was a high correlation between the visible part of the lesser trochanter and femoral version (R2 = 0.75; P < .001). The lesser trochanter was no longer visible with femoral retroversion in each of the 60 data sets.

Conclusion

The projected size of the lesser trochanter as available on plain pelvic AP radiographs correlates with native femoral anteversion.  相似文献   

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