Level of surgical experience is associated with change in hip center of rotation following cementless total hip arthroplasty: A radiographic assessment

SuperPath® vs. direct anterior approach : A retrospective comparison between two minimally invasive approaches in total hip arthroplasty

OBJECTIVE

Minimally invasive approaches are subject to controversy in orthopedic surgery. The aim of the current study was to compare the radiographic parameters between two minimally invasive approaches in total hip arthroplasty.

MATERIAL AND METHODS

Between January 2018 and February 2019, the radiographic parameters of 80 patients undergoing total hip arthroplasty via minimally invasive approaches (DAA: n = 40; SuperPath® SP: n = 40) have been measured. The radiographic analysis was performed with digital software tool mediCad® (HECTEC™ GmbH, Landshut, Germany).

RESULTS

Patients treated with DAA showed significantly higher inclination (SP: 39.7° ± 7.3° vs. DAA: 44.7° ± 5.3°) and significantly lower cup anteversion values (SP: 31.2° ± 7.9° vs. DAA: 27. 5° ± 5.3°, p < 0.001) than patients undergoing THA via SP postoperatively. The horizontal femoral offset was neither preoperatively nor postoperatively higher in DAA than in SP cohort (preoperative: p = 0.71, postoperative: p = 0.25) (preoperative: SP:37.2 mm ± 7.3 vs. DAA 38.2 mm ± 7.5; postoperative: SP: 38.0 mm ± 7.2 vs. DAA: 40.5 mm ± 7.0). At both times, the acetabular offset was significantly higher in DAA cohort than in SP cohort (preoperative: SP: 32.9 mm ± 5.9 vs. DAA: 36.8 mm ± 4.9; postoperative: SP: 28.9 mm ± 4.2 vs. DAA: 33.4 mm ± 3.8) (preoperative: 0.001; postoperative: p < 0.001). The vertical height was preoperatively and postoperatively not significantly higher in SP cohort than in DAA cohort (preoperative: SP: 16.1 mm ± 4.1 vs. DAA: 15.5 mm ± 4.9; postoperative: SP: 16.6 mm ± 4.6 vs. DAA: 16.1 mm ± 4.6) (preoperative: p = 0.77; postoperative: p = 0.58). The preoperatively existing leg length discrepancy of the affected leg could be compensated via surgery without showing significant differences between the two cohorts (preoperative: SP: -3.2 mm ± 5.4 vs. DAA: 1.9 mm ± 4.9; postoperative: SP: 1.5 mm ± 5.4 vs. DAA: 4.8 mm ± 5.6) (preoperative: p = 0.34; postoperative: p = 0.09).

CONCLUSION

The current study demonstrates suitable cup positioning and stem alignment in the coronal plane using minimal-invasive approaches DAA and Superpath®.

Restoration of hip geometry after total hip arthroplasty: retrospective comparison of two short stems and one straight stem

BACKGROUND

The preservation or restoration of hip geometry following total hip arthroplasty (THA) is of importance, considering that alterations in the centrum-collum-diaphysis (CCD)-angle, femoral offset (FO), acetabular offset (AO) and total offset (TO) change hip biomechanics. Therefore, the most suitable implant should be used. The aim of this study was to compare the ability of two short-stem-systems and one straight-stem-system to reconstruct hip geometry.

METHODS

Two-hundred-fifty-one patients (mean age: 62.0 ± 10.0 years; 51.8% males) undergoing THA with three different stem types were retrospectively included, after excluding 11 patients with missing radiological follow-up. Pre- and postoperative radiographic images (group I, ANA.NOVA Alpha Schaft Proxy®, ImplanTec, 12 options: n = 99; group II, Optimys® Mathys, 24 options: n = 62; group III: Corail®-System, DePuy-Synthes, 76 options: n = 90) were analyzed. Differences in pre- and postoperative hip geometry (i.e. CCD, FO, AO, TO) were compared between groups with one-way-analysis-of-variance (ANOVA), and post-hoc t-tests.

RESULTS

The CCD-angle increased by a mean of 8.4° ± 7.2° from pre-to postoperative, with no significant difference between groups (p = 0.097). Significantly larger increases in FO were observed for groups II (4.1 mm ± 7.8 mm) and III (4.9 ± 7.2 mm), in comparison to group I (1.6 ± 6.9 mm; p = 0.006). AO decreased by a mean of 2.2 ± 4.5 mm, with the largest decrease observed in group III (-3.3 ± 5.3 mm), and the smallest for group I (-1.4 ± 3.6 mm; p = 0.011). There was no significant difference in change of TO between groups (p = 0.177).

CONCLUSIONS

Reconstruction of hip geometry using a single-version novel short-stem-system is achievable with comparable results to stem-systems offering multiple options.

A Change in the Classical Order of Setting of Porous Metal Augments with Locked Cups in Hip Revision Surgery: Technical Note and Case Report

Introduction

Reconstruction of acetabular bone defects by the combination of trabecular metal augments and porous cups can be complex when extensive bone loss and poor-quality bone exists. The onset of porous cups with an interlocking mechanism may simplify surgical technique due to its superior initial mechanical stability. We endorse the possibility for a change in the classical order of setting of the augments and the cup.

Methods

We present a technical modification and a series of cases of three patients with Paprosky IIB and IIIA acetabular defects operated with a combination of porous metal augments and a porous cup. In all the three patients, the setting of the cup was done first and secured with locked screws, and then the augments were set in place as a wedge and fixed with screws in a standard fashion.

Results

The postoperative X-ray showed good position of implants with restoration of the center of rotation, and the patients had good recovery. Radiological evaluation in the midterm follow-up did not show mobilization of implants. Discussion. The use of metal porous augments is widely used for severe acetabular defects, being a versatile system to adapt to the different size defects. Nevertheless, its use may be technically demanding and time consuming. It is not infrequent that the setting of the augments conditions the final position of the cup with a possible interference with initial stability and eventually bone ingrowth of the cup. The interlocking mechanism offers an additional biomechanical stability and thus may allow us to place the cup first in the desired position with a less demanding technique.

Conclusion

With the use of locked-screw porous metal cups, the order of setting of implants may be changed in order to obtain a better restoration of the center of rotation and increased host-bone implant contact with a simplified surgical technique.

Optimal Center of Rotation for Ball-And-Socket Thumb Carpometacarpal Arthroplasty Identified Using Three-Dimensional Kinematic Analysis: A Pilot Study

Total joint arthroplasty is one of the surgical option for thumb carpometacarpal (CMC) joint arthritis, however the optimal position the center of rotation (COR) has not been quantified. The purpose of this study is to identify ideal ball-and-socket thumb carpometacarpal joint implants and the optimal position of the COR. We obtained eight right thumb computed tomography images each from ten healthy men, comprising four images each of thumbs at various angles of flexion-extension and abduction-adduction. We reconstructed 3D bone models on 3D CAD, created virtual ball-and-socket implants with three variables (neck offset, implant height, neck rotation), and found the optimal COR where the position change in the COR was smallest across various thumb positions. When the offset was 4.5 mm, neck rotation angle was 130.6° from the radial side to the palmar side of the first metacarpal, and implant height from the distal end of the metacarpal was 43.6 mm, we could restore almost normal kinematics. This study could serve as a reference for implant development and surgical technique guidelines.

Cup placement in primary total hip arthroplasty: how to get it right without navigation or robotics

Acetabular component orientation and position are important factors in the short- and long-term outcomes of total hip arthroplasty.

Different definitions of inclination and anteversion are used in the orthopaedic literature and surgeons should be aware of these differences and understand their relationships.

There is no universal safe zone.

Preoperative planning should be used to determine the optimum position and orientation of the cup and assess spinopelvic characteristics to adjust cup orientation accordingly.

A peripheral reaming technique leads to a more accurate restoration of the centre of rotation with less variability compared with a standard reaming technique.

Several intraoperative landmarks can be used to control the version of the cup, the most commonly used and studied is the transverse acetabular ligament.

The use of an inclinometer reduces the variability associated with the use of freehand or mechanical alignment guides.

The association between surgeon grade and risk of revision following total hip arthroplasty : an analysis of National Joint Registry data

AIMS

Total hip arthroplasties (THAs) are performed by surgeons at various stages in training with varying levels of supervision, but we do not know if this is safe practice with comparable outcomes to consultant-performed THA. Our aim was to examine the association between surgeon grade, the senior supervision of trainees, and the risk of revision following THA.

METHODS

We performed an observational study using National Joint Registry (NJR) data. We included adult patients who underwent primary THA for osteoarthritis, recorded in the NJR between 2003 and 2016. Exposures were operating surgeon grade (consultant or trainee) and whether or not trainees were directly supervised by a scrubbed consultant. Outcomes were all-cause revision and the indication for revision up to ten years. We used methods of survival analysis, adjusted for patient, operation, and healthcare setting factors.

RESULTS

We included 603,474 THAs, of which 58,137 (9.6%) procedures were performed by a trainee. There was no association between surgeon grade and all-cause revision up to ten years (crude hazard ratio (HR) 1.00 (95% confidence interval (CI) 0.94 to 1.07); p = 0.966), a finding which persisted with adjusted analysis. Fully adjusted analysis demonstrated an association between trainees operating without scrubbed consultant supervision and an increased risk of all-cause revision (HR 1.10 (95% CI 1.00 to 1.21); p = 0.045). There was an association between trainee-performed THA and revision for instability (HR 1.14 (95% CI 1.01 to 1.30); p = 0.039). However, this was not observed in adjusted models, or when trainees were supervised by a scrubbed consultant.

CONCLUSION

Within the current training system in England and Wales, appropriately supervised trainees achieve comparable THA survival to consultants. Trainees who are supervised by a scrubbed consultant achieve superior outcomes compared to trainees who are not supervised by a scrubbed consultant, particularly in terms of revision for instability. Cite this article: Bone Joint J 2022;104-B(3):341-351.

Association between surgeon grade and implant survival following hip and knee replacement: a systematic review and meta-analysis

OBJECTIVE

To investigate the association between surgeon grade (trainee vs consultant) and implant survival following primary hip and knee replacement.

DESIGN

A systematic review and meta-analysis of observational studies.

DATA SOURCES

MEDLINE and Embase from inception to 6 October 2021.

SETTING

Units performing primary hip and/or knee replacements since 1990.

PARTICIPANTS

Adult patients undergoing either a primary hip or knee replacement, predominantly for osteoarthritis.

INTERVENTION

Whether the surgeon recorded as performing the procedure was a trainee or not.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcome was net implant survival reported as a Kaplan-Meier survival estimate. The secondary outcome was crude revision rate. Both outcomes were reported according to surgeon grade.

RESULTS

Nine cohort studies capturing 4066 total hip replacements (THRs), 936 total knee replacements (TKRs) and 1357 unicompartmental knee replacements (UKRs) were included (5 THR studies, 2 TKR studies and 2 UKR studies). The pooled net implant survival estimates for THRs at 5 years were 97.9% (95% CI 96.6% to 99.2%) for trainees and 98.1% (95% CI 97.1% to 99.2%) for consultants. The relative risk of revision of THRs at 5 and 10 years was 0.88 (95% CI 0.46 to 1.70) and 0.68 (95% CI 0.37 to 1.26), respectively. For TKRs, the net implant survival estimates at 10 years were 96.2% (95% CI 94.0% to 98.4%) for trainees and 95.1% (95% CI 93.0% to 97.2%) for consultants. We report a narrative summary of UKR outcomes.

CONCLUSIONS

There is no strong evidence in the existing literature that trainee surgeons have worse outcomes compared with consultants, in terms of the net survival or crude revision rate of hip and knee replacements at 5-10 years follow-up. These findings are limited by the quality of the existing published data and are applicable to countries with established orthopaedic training programmes.

PROSPERO REGISTRATION NUMBER

CRD42019150494.

Accuracy of acetabular cup placement positively correlates with level of training

BACKGROUND

Accurate acetabular component placement may reduce the risk of complication after total hip arthroplasty (THA). While surgeon experience and volume may reduce outliers, little is known how cup positioning accuracy and consistency relates to level of training (resident, fellow, attending) and whether trainee level impacts the magnitude and direction of cup placement errors.

METHODS

Ninety patients undergoing posterolateral computer-assisted navigation THA were included for analysis. All surgery was performed by two fellowship-trained orthopaedic surgeons and assisted by a trainee (orthopedic resident (PGY 1-5) or fellow in adult reconstruction). In order to determine accuracy of cup placement in trainees and attendings, we used computer navigation to determine freehand cup placement by the trainee, then by the attending surgeon. Final cup inclination and version were determined and recorded by computer-assisted surgical navigation. Comparison of consistency in cup inclination and anteversion was made on values obtained by residents, fellows, and attendings and final values provided by the navigation system. In addition, to assess the role of training and repetition, acetabular cup inclination and version were compared between fellows during the first half and the second half of their training year. All comparisons were performed with the Student t-test except for comparison of rate of deviation from the safe zone, which were performed with the chi-square test. The level of significance was defined as p values ≤ 0.05 with 95% confidence interval, and trend toward significance was defined as p values ≤ 0.1.

RESULTS

Inclination deviation from the final position and cup version deviation from the final position were statistically significant between resident vs attendings (p < 0.001 (inclination), p < 0.001 (version)), fellow vs attendings (p < 0.001 (inclination), p < 0.001 (version)), and all trainee vs attendings (p < 0.001 (inclination), p < 0.001 (version)). In all comparisons, the attending surgeons placed the cup closer to the final cup position than both resident and fellows. Proportion of inclination deviation from the safe zone of residents was significantly higher than of attendings (p < 0.001) but no significant difference was observed between fellows and attending (p = 1.00). Compared to residents, fellows demonstrated lower proportion of inclination deviation from the safe zone of 3.3% vs 23.3% for fellows vs residents (p = 0.002) and tended to implant the cups in a more horizontal position (45.6 ± 6.6° [SD] and 42.7 ± 4.3°, respectively, p = 0.04). Compared to fellow, residents tended to implant the cup in a more anteverted position than the final cup version (9.6 ± 6.7° and 6.74 ± 5.6° [SD], p = 0.034). There was no statistically significant difference in cup position between attendings' free-hand and final (computer assisted) cup placement.

CONCLUSION

Accurate and consistent acetabular cup placement improves with level of training. Accurate and consistent acetabular cup version is harder to master as compared to acetabular cup inclination.

Surgeon Level of Expertise in Adult Reconstruction: A Brief Communication Regarding the Need for Reporting the Level of Expertise

The purpose of the current brief communication is to establish a discussion regarding level of expertise (LOE) documentation in future arthroplasty clinical studies and to document the trend in adoption of LOE among arthroplasty publications to date. A review of Arthroplasty Today, Journal of Arthroplasty (JOA), Journal of Bone and Joint Surgery (JBJS), and International Orthopedics (IO) databases for original studies published between April 2016 and July 2020 was performed. A total of 105 articles were identified and evaluated in Arthroplasty Today, 1011 in JOA, 127 in JBJS, and 383 in IO. Of 1011 articles identified in JOA, only one manuscript (1/1011; 0.1%), by Uluyardimci et.al, included the LOE of the surgeon(s) involved in the study. No articles in Arthroplasty Today (0/125; 0%), JBJS (0/127; 0%), or IO (0/383; 0%) reported the LOE according to Tang's recommendations during the same period. Documenting LOE may provide readers with additional information for incorporation of novel techniques into their practices as well as identify procedures that require a baseline LOE for effective performance. Further evaluation of LOE criteria may improve the reliability of the numeric scale, while widespread adoption of this scale will allow future outcome analysis by LOE.

A novel mechanical inclinometer device to measure acetabular cup inclination in total hip arthroplasty

It is well recognised that acetabular cup orientation influences patient function and implant survival post-THR. Reliable intra-operative determination of cup orientation remains a challenge. We describe the design and testing of a novel mechanical inclinometer to measure intra-operative acetabular cup inclination. The aim was to design a generic inclinometer to measure acetabular inclination to within + 5° without requiring modification to existing instrumentation while remaining easy to handle, robust/reusable, and sterilizable. The device was drafted using CAD software, prototyped using a 3D printer and constructed using stainless steel. Two experiments were undertaken to test accuracy: (1) the absolute accuracy was tested; (2) placement of an acetabular component using the device was compared to a freehand technique using a sawbone pelvis. 18 surgeons were asked to place an uncemented acetabular cup in a saw bone pelvis to a target of 40°. The average root-mean-square error was 1.1° (SD: 0.9°). Comparison showed that with the freehand component placement 50% of the surgeons were outside the specified range (35°-45°) where all participants achieved placement within range when using the inclinometer. This work demonstrates that the design and initial testing of a mechanical inclinometer which is suitable for use in determining the acetabular cup inclination in THR.

Surgical Approach and Reaming Depth Influence the Direction and Magnitude of Acetabular Center of Rotation Changes During Total Hip Arthroplasty

Background

Changes in acetabular or hip center of rotation (HCOR) commonly occur during acetabular component preparation during total hip arthroplasty (THA). HCOR displacement in mediolateral or superoinferior directions is known to influence offset and leg length, but the incidence and range of HCOR change in the anteroposterior direction is less understood as the sagittal plane cannot be measured on standard anteroposterior radiographs. This study assessed the 3-dimensional displacement of HCOR after cup implantation and evaluated for potential factors associated with increased acetabular component translations.

Methods

A total of 894 THAs were performed using a posterior, lateral, or direct anterior approach. Only intraoperative data from the navigation device were included in the analysis. All THAs performed between September 2015 and October 2017 were included. Paired t-tests were used to compare native HCOR and new HCOR values.

Results

The mean HCOR displacement in 3 directions was 4.97mm medially (P < .001), 0.83mm superiorly (P < .001), and 0.64mm posteriorly (P < .001). Subgroup analysis revealed greater posterior HCOR displacement with the anterior approach than the lateral/posterior approach (2.32mm vs 0.44mm; P < .001). Increasing medial HCOR displacement also resulted in increased superior and posterior HCOR displacement across surgical cases (P < .001).

Conclusions

HCOR displacement is commonly observed in medial, superior, and posterior directions. HCOR changes are influenced by surgical approach, potentially secondary to patient positioning, with greater posterior HCOR displacement observed in anterior cases. Surgeons should be aware of these factors, particularly in cases with deficient or reduced posterior column bone stock.

Mid-term and long-term results of restoring rotation center in revision hip arthroplasty

Background

To restore rotation center exactly in revision hip arthroplasty is technically challenging, especially in Paprosky type III. The technical difficulty is attributable to the complicated acetabular bone defect. In this study, we discussed the method of restoring rotation center in revision hip arthroplasty and reported the clinical and radiological outcome of mid-term and long-term follow-up.

Methods

This study retrospectively reviewed 45 patients (48 hips) who underwent revision hip arthroplasty, in which 35 cases (35 hips) were available for complete follow-up data. During the operation, the acetabular bone defect was reconstructed by impaction morselized bone graft, and the hip rotation center was restored by using remnant Harris fossa and acetabular notches as the marks. The clinical outcome was assessed using the Harris hip score. Pelvis plain x-ray was used to assess implant migration, stability of implants, and incorporation of the bone graft to host bone.

Result

The average follow-up duration was 97.60 months (range 72–168 months). The average Harris hip score improved from 29.54 ± 10.87 preoperatively to 83.77 ± 5.78 at the last follow-up. The vertical distance of hip rotation center measured on pelvis x-ray was restored to normal, with the mean distance (15.24 ± 1.31) mm (range 12.4~17.3 mm). The mean loss of vertical distance of hip rotation center was (2.21 ± 0.72) mm (range 1.1 ~ 5.3 mm) at the last follow-up.

Conclusion

Satisfactory clinical and radiological outcome can be obtained through restoring hip rotation center by using remnant Harris fossa and acetabular notches as the anatomical marks in revision hip arthroplasty.

A novel positioner for accurately sitting the acetabular component: a retrospective comparative study

Introduction

In this study, we described a positioner which allows a combination of preoperative plan and intraoperative insertion of the cup to improve the reconstruction of the rotation center of the hip.

Materials and methods

A retrospective study was conducted on 32 consecutive patients (group A) using this positioner and 40 consecutive patients (group B) using conventional method; radiological parameters and clinical measurements before operation and at last follow-up were collected and evaluated.

Results

Group A had a reconstructed center of rotation (COR) that was 0.19 mm closer to the anatomic COR in height (P < 0.005), compared with group B with 3.45 mm vertical dislocation. There were no statistically significant differences in the horizontal displacement between the two groups. The accuracy of cup inclination was 42.14 ± 3.57 in the group A and 38.73 ± 7.65 in the group B (P = 0.015). The accuracy of cup anteversion was 14.82 ± 1.44 in the group A and 13.08 ± 5.95 in the group B (P = 0.082). All cups in the group A were radiologically stable, while one cup in the group B was radiologically unstable and was successfully treated with second-stage revision. Both of the groups obtained a higher mean postoperative Harris Hip Score.

Conclusions

Utilizing this positioner helps to restore the COR position more precisely and provides satisfactory radiological and clinical outcomes in the short term, and more studies are required before its widespread adoption for complicated cases.

High Variability of Acetabular Offset in Primary Hip Osteoarthritis Influences Acetabular Reaming-A Computed Tomography-Based Anatomic Study

BACKGROUND

The objectives of the present study were to (1) evaluate the accuracy and reliability of native acetabular offset (AO) measurements performed on conventional supine anterior-posterior (ap) pelvis radiographs with reference to computed tomography (CT) in patients with end-stage hip osteoarthritis (OA); (2) determine the minimum and maximum amount of medialization of the center of rotation (COR) simulating different reaming techniques; and (3) identify patients at increased risk of excessive medialization of the COR.

METHODS

A consecutive series of corresponding 131 CT scans and radiographs of patients with primary hip OA was evaluated using validated software for three-dimensional acetabular and femoral measurements. We simulated the implantation of a hemispherical press-fit cup comparing anatomic and conventional reaming techniques and assessed corresponding changes in AO.

RESULTS

Standardized ap pelvis radiographs allowed for an accurate and reliable assessment of AO compared with CT. Cup placement in the most lateral position (anatomic reaming technique) resulted in a mean implant-related medialization of 5.9 ± 3.4 mm. Anatomic cup placement did not require reaming to the true floor in 64 hips (49%). With the conventional reaming technique, the total medialization of the COR (implant-related and reaming-related) was 6.8 ± 2.9, with 34% of cases having a medialization ≥8 mm.

CONCLUSION

The present study highlights the variability of acetabular anatomy in patients with primary OA. AO can be accurately and reliably determined on conventional radiographs and appears to be independent of femoral shape and geometry. Depending on the preferred reaming technique a substantial number of patients appear at risk for excessive cup medialization.

Fourth-generation ceramic-on-ceramic THA results in improvements in midterm outcomes compared to third-generation THA but does not resolve noise problems: a cohort study of a single-hip system

BACKGROUND

Using data from the Korean Hip Registry, we aimed to investigate mid-term clinical and radiographic outcomes, including the prevalence of periprosthetic joint infection (PJI), osteolysis, and component loosening or dislocation, and to analyze the incidence of bearing-related complications following modern ceramic-on-ceramic (COC) total hip arthroplasty (THA) using a single cementless hip system.

METHODS

Four hundred eighty-two patients (602 hips) who underwent Forte or Delta COC THAs with a single hip system and had a minimum 5-year follow-up were identified. The sample included 243 (50.4%) women and 239 (49.6%) men with a mean age of 50.6 years (range: 18-83 years). The Forte group comprised 310 hips, and the Delta group comprised 292 hips. The mean follow-up was 6.1 years (range: 5-10.2 years).

RESULTS

Cup orientation did not differ between groups. No hip had a PJI or osteolysis in either group. All acetabular components and all but two femoral components (in the Delta group) were well fixed. Dislocations occurred in six (1.9%) hips in the Forte group and one (0.3%) hip in the Delta group (p = 0.124). A total of nine (1.5%) revisions were performed. The 5-year survival rates for all-cause revisions were 98.4 and 98.6%, respectively. One (0.3%) ceramic head fracture occurred in the Forte group. Sixteen (5%) hips exhibited clicking and 6 (2%) hips had squeaking in the Forte group; 16 (6%) hips exhibited clicking and 5 (2%) hips had squeaking in the Delta group. Multiple regression analysis revealed that noise generation was unassociated with any factor.

CONCLUSIONS

From the Korean Hip Registry data, THA with modern ceramic bearings showed encouraging results, with lower risks of PJI, osteolysis, and component loosening. In particular, Delta COC THA resulted in no PJI or ceramic fracture and had a reduced dislocation risk. However, associated noise remains a concern.