Contemporary posterior surgical approach in total hip replacement: still more reoperations due to dislocation compared with direct lateral approach? An observational study of the Swedish Hip Arthroplasty Register including 156,979 hips

Dislocation of primary total hip arthroplasty: Analysis of risk factors and preventive options

Total hip arthroplasty (THA) is one of the most successful elective operations in orthopedic surgery for improving pain and functional disability in patients with end-stage joint disease. However, dislocation continues to be a troublesome complication after THA, as it is a leading cause of revision and is associated with substantial social, health, and economic costs. It is a relatively rare, usually early occurrence that depends on both the patients' characteristics and the surgical aspects. The most recent and important finding is the special attention to be given preoperatively to spinopelvic mobility, which is closely related to the incidence of dislocation. Consequently, clinical and radiographic assessment of the lumbar spine is mandatory to identify an altered pelvic tilt that could suggest a different positioning of the cup. Lumbar spinal fusion is currently considered a risk factor for dislocation and revision regardless of whether it is performed prior to or after THA. Surgical options for its treatment and prevention include the use of prostheses with large diameter of femoral head size, dual mobility constructs, constrained liners, and modular neck stems.

Intraoperative Assessment of Stability in Total Hip Arthroplasty: A Novel Method Utilizing Implant Collinearity

Background

Hip dislocation remains a leading cause of revision following total hip arthroplasty, and intraoperative assessment of acetabular positioning can be difficult to perform. There are multiple clinical tests, as well as computer and robotic techniques, that aim to reduce dislocation rates after hip arthroplasty. These approaches aim to optimize the relationship between acetabular and femoral component positioning. It is hypothesized in this study that implant collinearity assessment intraoperatively can help determine appropriate acetabular component position. More specifically, implant collinearity, when achieved with a specific leg position, can reliably predict appropriate acetabular positioning.

Methods

A single-surgeon, single-centered study with 55 patients was undertaken between August 2017 and March 2020. Using preoperative imaging and computer simulation, data points were taken for 3 different acetabular configurations and comparing using 2 femoral positions. The angle differences from the collinear position (0 degrees) were compared between groups.

Results

A total of 55 patients' imaging was analyzed using 3 acetabular configurations and 2 femoral positions. The test leg position (30-degree flexion/30-degree internal rotation/10-degree adduction) was closer to collinearity than the control position (30-degree flexion/30-degree internal rotation/0-degree adduction) in all 3 acetabular configurations by a mean of 8 degrees (P < .001), 7 degrees (P < .001), and 4 degrees (P < .001), respectively.

Conclusions

The use of a 10-degree adducted position more reliably recreates implant collinearity when determining acetabular positioning during total hip arthroplasty. This intraoperative test adds another data point to assist the surgeon in achieving safe component positioning.

What is the Role of Stem Size and Offset in the Risk of Nonseptic Revision of the Exeter® 150-mm Stem? A Study From the Swedish Arthroplasty Register

BACKGROUND

The Exeter® stem is used worldwide, often in older patients, and it is the second most commonly used cemented stem design in Sweden. Previous studies have shown that for cemented stems with a composite beam, the smallest sizes result in an increased risk of revision for mechanical failure. However, little is known about whether the survivorship of the polished Exeter stem, which generally has been shown to be good, might be associated with design parameters such as stem dimensions or offset at extreme implant sizes.

QUESTION/PURPOSE

Are differences in (1) stem size or (2) offset of the standard Exeter V40 150-mm stem associated with differences in the risk of stem revision for aseptic loosening?

METHODS

Between 2001 and 2020, 47,161 Exeter stems were reported to the Swedish Arthroplasty Register, with very high coverage and completeness documented during the period studied. In this cohort, we included patients with primary osteoarthritis who underwent surgery with a standard Exeter stem length of 150 mm and V40 cone with any type of cemented cups that had had at least 1000 reported insertions. This selection resulted in a study cohort representing 79% (37,619 of 47,161) of the total number of Exeter stems in the registry during that time. The primary study outcome was stem revision for aseptic indications such as loosening, periprosthetic fracture, dislocation, and implant fracture. A Cox regression was performed, with adjustment for age, gender, surgical approach, year of surgery, use of highly crosslinked polyethylene cups, and femoral head size and length dictated by the shape of the head trunnion. Adjusted hazard ratios are presented with 95% confidence intervals. Two separate analyses were performed. The first analysis excluded stems with the highest offsets (50 mm and 56 mm, which were not available for stem size 0). The second analysis excluded stem size 0 to include all offsets. Because stem survival was not proportional over time, we divided the analyses into two insertion periods, 0 to 8 years and beyond 8 years.

RESULTS

Stem size 0 (compared to size 1) was associated with an increased risk of revision up to 8 years when all stem sizes were included (first analysis 0 to 8 years, HR 1.7 [95% CI 1.2 to 2.3]; p = 0.002). Forty-four percent (63 of 144) of revisions of size 0 stems were for periprosthetic fracture. There was no consistent association between stem size and risk of aseptic stem revision when size 0 was excluded in the second analysis beyond 8 years. The most common offset (44 mm) was associated with an increased risk of revision (compared with 37.5 mm) up to 8 years when all sizes were included (first analysis, HR 1.6 [95% CI 1.1 to 2.1]; p = 0.01). In the second analysis (beyond 8 years, all offsets included), offset of 44 mm was compared with offset of 37.5 mm; compared with the first period, this offset was associated with a reduced risk (HR 0.6 [95% CI 0.4 to 0.9]; p = 0.005).

CONCLUSION

We found overall high survival of the Exeter stem, with generally little or no influence of stem variations on the risk of aseptic revision. However, stem size 0 was associated with an increased risk of revision mainly for periprosthetic fractures. If the femoral anatomy offers a choice between sizes 0 and 1 in patients with poor bone quality who are at risk of periprosthetic fracture, our data speak in favor of choosing the larger stem if the surgeon believes it is safe to insert the larger size, or, if available, another stem design that has a documented lower risk of this complication. For patients with good cortical bone quality but very narrow canals, a cementless stem may also be a good alternative.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Hip precautions after posterior-approach total hip arthroplasty among patients with primary hip osteoarthritis do not influence early recovery: a systematic review and meta-analysis of randomized and non-randomized studies with 8,835 patients

BACKGROUND AND PURPOSE

Hip precautions are routinely prescribed to patients with osteoarthritis to decrease dislocation rates after total hip arthroplasty (THA) using a posterior approach. However, recommendations have been based on very low certainty of evidence. We updated the evidence on the influence of hip precautions on early recovery following THA by this systematic review.

MATERIALS AND METHODS

We performed systematic searches for randomized controlled trials (RCT) and non-randomized (NRS) studies in MEDLINE, Embase, PEDro, and CINAHL published from 2016 to July 2022. 2 reviewers independently included studies comparing postoperative precautions with minimal or no precautions, extracted data, and assessed the risk of bias. Random effects meta-analyses were used to synthesize the results. The certainty of the evidence was rated by the Grading of Recommendations Assessment and Evaluation approach. The critical outcome was the risk of hip dislocations within 3 months of surgery. Other outcomes were long-term risk of dislocation and reoperation, self-reported and performance-based assessment of function, quality of life, pain, and time to return to work.

RESULTS

4 RCTs and 5 NRSs, including 8,835 participants, were included. There may be no or negligible difference in early hip dislocations (RCTs: risk ratio [RR] 1.8, 95% confidence interval [CI] 0.6-5.2; NRS: RR 0.9, CI 0.3-2.5). Certainty in the evidence was low for RCTs and very low for NRSs. Finally, precautions may reduce the performance-based assessment of function slightly, but the evidence was very uncertain. For all other outcomes, no differences were found (moderate to very low certainty evidence).

CONCLUSION

The current evidence does not support routinely prescribing hip precautions post-surgically for patients undergoing THA to prevent hip dislocations. However, the results might change with high-quality studies.

Approaches for Total Hip Arthroplasty: A Systematic Review

These surgical procedures have their own challenges, limitations, and success rate. The choice of surgical approach will depend on many factors including the surgeon's choice, type of pathology, bone stock, age of the patient, and experience of the surgeon. Whichever approach is used for total hip arthroplasty (THA), the primary goals of the surgery would be pain relief and enhancement in the quality of the patient's life suffering from hip pathologies. To further understand the advantages and potential pitfalls associated with different surgical approaches, we conducted a review study comparing different surgical approaches for THA in terms of their clinical and functional outcomes. All the studies done on surgical approaches used in THA published articles in the English language and from 2015 onward were included in the review. The databases searched were COCHRANE, MEDLINE, PEDRO, CINHAL, etc. Search engines that were searched were Google Scholar, Pub Med, and Science Direct. As per the inclusion criteria, out of 50 studies, 26 studies were included in the study which underwent critical analysis. Considering all the factors reviewed from the literature, the posterior approach or posterolateral approach is optimally beneficial.

Hip arthroplasty dislocation risk calculator: evaluation of one million primary implants and twenty-five thousand dislocations with deep learning artificial intelligence in a systematic review of reviews

PURPOSE

This paper aims to provide an overview of the possibility regarding the artificial intelligence application in orthopaedics to predict dislocation with a calculator according to the type of implant (hemiarthroplasty, standard total hip arthroplasty, dual mobility, constrained cups) after primary arthroplasty.

MATERIAL AND METHODS

Among 75 results for primary arthroplasties, 26 articles were reviews on dislocation after hemiarthroplasty, 40 after standard total hip arthroplasty, seven about primary dual-mobility arthroplasty (DM THA), and two reviews about constrained implants. Although our search method for systematic reviews covers ten years (2012-2022), none for dual mobility was published before 2016, showing a recent explosion of original articles on this subject. A total of 1,069,565 implants and 26,488 dislocations in primary arthroplasties are included in these 75 reviews. We used a supervised learning model in which models assign objects to groups as input and artificial neural network (ANN) with nodes, hidden layers, and output layers. We considered only four implant types as the input layer. We considered the patient's factors (indication for THA, demographics, spine surgery, and neurologic disease) as the second input values (hidden layer). We considered the implant position as the third input (hidden layer) property including head size, combined anteversion, or spinopelvic alignment. Surgery-related factors, approach, capsule repair, etc. were the fourth input values (hidden layer). The output was a post-operative dislocation or not within three months.

RESULTS

The accuracy for predicting dislocation with this systematic review was 95%. Dislocation risk, based on the type of implant, was wide-ranging, from 0 to 3.9% (mean 0.31%) for the 3045 DM THA, from 0.2 to 1.2% (overall 0.91%) for the 457 constrained liners, from 1.76 to 4.2% (mean 2.1%) for 895,734 conventional total hip arthroplasties, and from 0.76 to 12.2% (mean 4.5%) for 170,329 hemiarthroplasties. In the conventional THA group, many factors increase the risk of dislocation according to the calculator, and only a few (big head, anterior approach) decrease the risk, but not very significantly. In the hemiarthroplasty group, many factors can increase the risk of dislocation until 30%, but none could decrease the risk. According to the calculator, the DM THA and the constrained liner markedly decreased the risk and were not affected by implant position, spine surgery, and spinopelvic position.

CONCLUSION

To our knowledge, this study is the first to yield an implant-specific dislocation risk calculator that incorporates the patient's comorbidities, the position of components, and surgery factors affecting instability risk.

Risk factors for revision surgery due to dislocation within 1 year after 111,711 primary total hip arthroplasties from 2005 to 2019: a study from the Norwegian Arthroplasty Register

BACKGROUND AND PURPOSE

Dislocation of a hip prosthesis is the 3rd most frequent cause (after loosening and infection) for hip revision in Norway. Recently there has been a shift in surgical practice including preferred head size, surgical approach, articulation, and fixation. We explored factors associated with the risk of revision due to dislocation within 1 year and analyzed the impact of changes in surgical practice.

PATIENTS AND METHODS

111,711 cases of primary total hip arthroplasty (THA) from the Norwegian Arthroplasty Register were included (2005-2019) after primary THA with either 28 mm, 32 mm, or 36 mm femoral heads, or dualmobility articulations. A flexible parametric survival model was used to calculate hazard ratios for risk factors. Kaplan-Meier survival rates were calculated.

RESULTS

There was an increased risk of revision due to dislocation with 28 mm femoral heads (HR 2.6, 95% CI 2.0-3.3) compared with 32 mm heads. Furthermore, there was a reduced risk of cemented fixation (HR 0.6, CI 0.5-0.8) and reverse hybrid (HR 0.6, CI 0.5-0.8) compared with uncemented. Also, both anterolateral (HR 0.5, CI 0.4-0.7) and lateral (HR 0.6, CI 0.5-0.7) approaches were associated with a reduced risk compared with the posterior approach. The time-period 2010-2014 had the lowest risk of revision due to dislocation. The trend during the study period was towards using larger head sizes, a posterior approach, and uncemented fixation for primary THA.

INTERPRETATION

Patients with 28 mm head size, a posterior approach, or uncemented fixation had an increased risk of revision due to dislocation within 1 year after primary THA. The shift from lateral to posterior approach and more uncemented fixation was a plausible explanation for the increased risk of revision due to dislocation observed in the most recent time-period. The increased risk of revision due to dislocation was not fully compensated for by increasing femoral head size from 28 to 32 mm.

What Can We Learn From Surgeons Who Perform THA and TKA and Have the Lowest Revision Rates? A Study from the Australian Orthopaedic Association National Joint Replacement Registry

BACKGROUND

Long-term implant survivorship in THA and TKA involves a combination of factors related to the patient, the implants used, and the decision-making and technical performance of the surgeon. It is unclear which of these factors is the most important in reducing the proportion of revision surgery.

QUESTIONS/PURPOSES

We used data from a large national registry to ask: In patients receiving primary THA and TKA for a diagnosis of osteoarthritis, do (1) the reasons for revision and (2) patient factors, the implants used, and the surgeon or surgical factors differ between surgeons performing THA and TKA who have a lower revision rate compared with all other surgeons?

METHODS

Data were analyzed for all THA and TKA procedures performed for a diagnosis of osteoarthritis from the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) from September 1, 1999, when collection began, to December 31, 2018. The AOANJRR obtains data on more than 98% of joint arthroplasties performed in Australia. The 5-year cumulative percent revision (CPR) was identified for all THAs and TKAs performed for a diagnosis of osteoarthritis with 95% confidence intervals (overall CPR); the 5-year CPR with 95% CIs for each surgeon was calculated for THA and TKA separately. For surgeons to be included in the analysis, they had to have performed at least 50 procedures and have a 5-year CPR. The 5-year CPR with 95% CIs for each THA and TKA surgeon was compared with the overall CPR. Two groups were defined: low revision rate surgeons (the upper confidence level for a given surgeon at 5 years is less than 3.84% for THA and 4.32% for TKA), and all other surgeons (any surgeon whose CPR was higher than those thresholds). The thresholds were determined by setting a cutoff at 20% above the upper confidence level for that class. The approach we used to define a low revision rate surgeon was similar to that used by the AOANJRR for determining the better-performing prostheses and is recommended by the International Prosthesis Benchmarking Working Group. By defining the groups in this way, a significant difference between these two groups is created. Determining a reason for this difference is the purpose of presenting the proportions of different factors within each group. The study group for THA included 116 low revision rate surgeons, who performed 88,392 procedures (1619 revised, 10-year CPR 2.7% [95% CI 2.6% to 2.9%]) and 433 other surgeons, who performed 170,094 procedures (6911 revised, 10-year CPR 5.9% [95% CI 5.7% to 6.0%]). The study group for TKA consisted of 144 low revision rate surgeons, who performed 159,961 procedures (2722 revised, 10-year CPR 2.6% [95% CI 2.5% to 2.8%]) and 534 other surgeons, who performed 287,232 procedures (12,617 revised, 10-year CPR 6.4% [95% CI 6.3% to 6.6%]). These groups were defined a priori by their rate of revision, and the purpose of this study was to explore potential reasons for this observed difference.

RESULTS

For THA, the difference in overall revision rate between low revision rate surgeons and other surgeons was driven mainly by fewer revisions for dislocation, followed by component loosening and fracture in patients treated by low revision rate surgeons. For TKA, the difference in overall revision rate between low revision rate surgeons and other surgeons was driven mainly by fewer revisions for aseptic loosening, followed by instability and patellofemoral complications in patients treated by low revision rate surgeons. Patient-related factors were generally similar between low revision rate surgeons and other surgeons for both THA and TKA. Regarding THA, there were differences in implant factors, with low revision rate surgeons using fewer types of implants that have been identified as having a higher-than-anticipated rate of revision within the AOANJRR. Low revision rate surgeons used a higher proportion of hybrid fixation, although cementless fixation remained the most common choice. For surgeon factors, low revision rate surgeons were more likely to perform more than 100 THA procedures per year, while other surgeons were more likely to perform fewer than 50 THA procedures per year. In general, the groups of surgeons (low revision rate surgeons and other surgeons) differed less in terms of years of surgical experience than they did in terms of the number of cases they performed each year, although low revision rate surgeons, on average, had more years of experience and performed more cases per year. Regarding TKA, there were more differences in implant factors than with THA, with low revision rate surgeons more frequently performing patellar resurfacing, using an AOANJRR-identified best-performing prosthesis combination (with the lowest rates of revision), using fewer implants that have been identified as having a higher-than-anticipated rate of revision within the AOANJRR, using highly crosslinked polyethylene, and using a higher proportion of cemented fixation compared with other surgeons. For surgeon factors, low revision rate surgeons were more likely to perform more than 100 TKA procedures per year, whereas all other surgeons were more likely to perform fewer than 50 procedures per year. Again, generally, the groups of surgeons (low revision rate surgeons and other surgeons) differed less in terms of years of surgical experience than they did in terms of the number of cases they performed annually, although low revision rate surgeons, on average, had more years of experience and performed more cases per year.

CONCLUSION

THAs and TKAs performed by surgeons with the lowest revision rates in Australia show reductions in all of the leading causes of revision for both THA and TKA, in particular, causes of revision related to the technical performance of these procedures. Patient factors were similar between low revision rate surgeons and all other surgeons for both THA and TKA. Low revision rate THA surgeons were more likely to use cement fixation selectively. Low revision rate TKA surgeons were more likely to use patella resurfacing, crosslinked polyethylene, and cemented fixation. Low revision rate THA and TKA surgeons were more likely to use an AOANJRR-identified best-performing prosthesis combination and to use fewer implants identified by the AOANJRR as having a higher-than-anticipated revision rate. To reduce the rate of revision THA and TKA, surgeons should consider addressing modifiable factors related to implant selection. Future research should identify surgeon factors beyond annual case volume that are important to improving implant survivorship.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Fast-track revision hip arthroplasty: a multicenter cohort study on 1,345 elective aseptic major component revision hip arthroplasties

BACKGROUND AND PURPOSE

Data on application of fasttrack/enhanced recovery protocols in revision hip arthroplasty (R-THA) surgery is scarce. We report length of stay (LOS), risk of LOS > 5 days, and readmission ≤ 90 days after revision hip arthroplasty in centers with a well-established fast-track protocol in both primary and revision procedures.

PATIENTS AND METHODS

This is an observational cohort study from the Centre for Fast-track Hip and Knee Replacement and the Danish Hip Arthroplasty Register. Consecutive elective aseptic major component revision hip arthroplasties from 6 dedicated fast-track centers from 2010 to 2018 were included.

RESULTS

1,345 R-THAs were analyzed, including 23% total revisions, 52% acetabular component revisions, and 25% femoral component revisions. Mean age was 70 years (SD 12) and 61% were female. Median LOS was 3 days (interquartile range [IQR] 2-6), decreasing from median 6 (IQR 3-10) days in 2010 to 2 (IQR 1-4) days in 2018. The 90-day readmission rate was 20%, but showed a fluctuating and increasing trend from 13% in 2010 to 28% in 2018. Risk factors for LOS > 5 days and readmission were use of walking aid, preoperative hemoglobin ≤ 13 g/dL, pharmacological treated psychiatric disorder, age ≥ 80 years, age 70-79 years (only LOS > 5 days), cardiac disease (only LOS > 5 days), pulmonary disease (only readmission), BMI ≥ 35 (only LOS > 5 days) and ≥ 1 previous revision (only LOS > 5 days).

INTERPRETATION

LOS decreased to median 2 days at the end of the study period, but the 90 days readmission risk remained high (> 20%). Several risk factors for postoperative complications were identified, suggesting that at-risk patients should be treated using an extended fast-track/enhanced recovery protocol focusing on preoperative optimization and postoperative monitoring as well as surgical techniques to reduce hip dislocations.

Influence of implant variations on survival of the Lubinus SP II stem: evaluation of 76,530 hips in the Swedish Arthroplasty Register, 2000-2018

Background and purpose - Almost all prosthetic implant brands include several variations. Most studies on implant performance investigate an implant system without sub-analysis of implant attributes. We studied the influence of design variations during the last 2 decades on implant survival of the most frequently used cemented femoral stem, the Lubinus SPII, reported to the Swedish Arthroplasty Register (SHAR). Patients and methods - Between 2000 and 2018, 100,032 cemented Lubinus SP II stems had been reported to SHAR. Patients with primary osteoarthritis operated on with stem length 150 mm together with a cemented cup from the same manufacturer (n = 76,530) were included in this analysis. Primary study outcome was non-infectious stem revision. Cox regression with adjustment for age, sex, surgical approach, and year of surgery was used. Hazard rates (HR) are presented with 95% confidence intervals (CI). Results - Average follow-up was 7.6 years (SD 4.2). At 18 years the overall stem survival was 99.1 (CI 98.9-99.3). Increased revision rate was observed for stems with extra offset, when a long or an extra-long head length had been used. Smaller stem sizes, in particular the smallest stem size (01), substantially increased the rate of mechanical failure as reflected by an almost 10 times increased rate of revision compared with the standard size (2). Interpretation - In this study with larger sample size and longer follow-up than previously presented from the same register, we observed more pronounced effects of previously documented design variations. Based on our results, surgeons using the Lubinus SPII stems are advised to consider an alternative solution if a Lubinus stem size 01, Lubinus extra offset, or an extra-long head seems to be the most suitable choice at the preoperative planning.

Dislocation of Total Hip Replacement in Femoral Neck Fracture: Do Surgical Approach and Dual Mobility Implant Matter?

INTRODUCTION

Total hip replacement (THR) in the neck of femur fracture in the elderly is associated with a higher risk of dislocation compared to hemiarthroplasty of hip or total hip replacement in the native hip. There is uncertainty regarding combining surgical approach, femoral head size, and the usage of single bearing or dual mobility to reduce the risk of dislocation. This study looks into the bearing of the prosthesis for posterior or lateral surgical hip approach as well as their head size to give a stable hip to these vulnerable groups of patients.

METHODS

Initial data were collected retrospectively from February 2017 till May 2019 from the electronic records database and clinical notes. Patients included in the study had a femoral neck fracture (age >60 years) who underwent a total hip replacement. Subsequent data were collected prospectively from June 2019 to July 2020.

RESULTS

High rate of dislocation was found with posterior approach and single bearing prosthesis. However, if dual mobility prosthesis was used while using the posterior approach the dislocation rate was very low. Also, with lateral approach and single bearing prosthesis using large femoral head size, the dislocation rate was negligible.

CONCLUSIONS

We recommend a dual mobility prosthesis for posterior approach THR and lateral approach with single-bearing hip replacement with large size femoral head. The dislocation rate is low using this principle irrespective of the surgical approach.

Posterior versus lateral surgical approach: functionality and quality of life after total hip arthroplasty in a matched cohort study

BACKGROUND

One of the most controversial aspects for maximizing outcomes after total hip arthroplasty (THA) remains the surgical approach to the hip joint. The posterior (PA) and lateral approaches (LA) are the two most commonly performed approaches used worldwide, but sparse data are available for their comparison in terms of health-related quality-of-life (HRQoL). The aim of this study was to assess the role of the PA and LA in the HRQoL and hip functionality of patients who underwent primary and elective THA for osteoarthritis, after a minimum 2-year follow-up.

METHODS

One hundred twenty-eight patients (140 THAs: 68 with PA and 72 with LA) were evaluated in a matched cohort study. Data gathered included the body mass index, the American Society of Anesthesiologists score, surgery time, serum creatine phosphokinase (CpK) levels, estimated intraoperative blood loss and intra- or postoperative complications. Preoperatively and at the last follow-up, the activities of daily living, and the instrumental activities of daily living (IADL) scales, the Western Ontario and Mac Master University (WOMAC) Questionnaire, the Harris Hip Score (HHS) and the Visual Analogue Scale (VAS) were used to assess HRQoL and functionality. The Short Form-36 Health Survey (SF-36) Questionnaire was administered at the last follow-up.

RESULTS

Postoperatively, CpK was higher in the LA group compared to the PA (695 ± 648 vs. 447 ± 326 UI/L, p < 0.001). At a mean follow-up of 47 ± 22 months for the LA group and 42 ± 29 months for the PA group, IADL, VAS, HHS and WOMAC scores significantly improved for both groups (all p < 0.001), but PA reported better VAS, residual pain and WOMAC scores (p = 0.002, p = 0.004 and p = 0.018, respectively). The PA group demonstrated a significant higher mental SF-36 subscale values than the LA group (49 ± 13 vs. 42 ± 19, p = 0.001). The LA group showed a higher number of Trendelenburg signs (p = 0.029). On the contrary, the PA group showed a higher number of leg lengthening (p = 0.020); however, most of these cases was less than the clinically significant value of 10 mm (p = 0.738).

CONCLUSIONS

Patients who underwent THA performed with the PA reported greater improvement in HRQoL with lower residual pain, postoperative muscle damage and Trendelenburg signs than those who underwent the LA.

Total Hip Arthroplasty for Femoral Neck Fracture: What Are the Contemporary Reasons for Failure?

BACKGROUND

Total hip arthroplasty (THA) for femoral neck fracture (FNF) appears to provide superior functional outcomes compared to hemiarthroplasty in selected active, elderly patients; however, the historical tradeoff has been higher risk of complications including dislocation. We aimed to describe implant survivorship and reasons for failure after THA for FNFs.

METHODS

We identified 217 FNFs treated with THA from 2000 to 2017 from our institutional total joint registry (during the same time period 2039 FNFs were treated with hemiarthroplasty). Mean age was 70 years, and 65% were female. Cemented femoral components were utilized in 41%. Approach was anterolateral in 71%, posterior in 21%, and direct anterior in 8%. Dual-mobility constructs were utilized in 3%. A competing risk model accounting for death was used to analyze revisions and complications. Mean follow-up was 6 years.

RESULTS

The 5-year cumulative incidence of any revision was 8%. Nineteen hips were revised for the following indications: postoperative periprosthetic femur fracture (6: 3 uncemented stems and 3 cemented), infection (5), aseptic loosening of the femoral component (3: 2 cemented and 1 uncemented), dislocation (3), iliopsoas impingement (1), and liner dissociation (1). The 5-year cumulative incidence of periprosthetic femur fractures was 7%, including 7 intraoperative fractures and 11 postoperative fractures. The 5-year cumulative incidence of dislocation was 1.4%.

CONCLUSION

The 5-year cumulative incidence of any revision after THA for FNFs was 8%, mostly attributed to periprosthetic fracture and infection. Hip instability was not as common after FNF with contemporary patient selection, techniques, and implants compared to previous series.

LEVEL OF EVIDENCE

Prognostic, level III.

A systematic review and meta-analysis of the hip capsule innervation and its clinical implications

Detailed understanding of the innervation of the hip capsule (HC) helps inform surgeons' and anaesthetists' clinical practice. Post-interventional pain following radiofrequency nerve ablation (RFA) and dislocation following total hip arthroplasty (THA) remain poorly understood, highlighting the need for more knowledge on the topic. This systematic review and meta-analysis focuses on gross anatomical studies investigating HC innervation. The main outcomes were defined as the prevalence, course, density and distribution of the nerves innervating the HC and changes according to demographic variables. HC innervation is highly variable; its primary nerve supply seems to be from the nerve to quadratus femoris and obturator nerve. Many articular branches originated from muscular branches of the lumbosacral plexus. It remains unclear whether demographic or anthropometric variables may help predict potential differences in HC innervation. Consequently, primary targets for RFA should be the anterior inferomedial aspect of the HC. For THA performed on non-risk patients, the posterior approach with capsular repair appears to be most appropriate with the lowest risk of articular nerve damage. Care should also be taken to avoid damaging vessels and muscles of the hip joint. Further investigation is required to form a coherent map of HC innervation, utilizing combined gross and histological investigation.

A Complication-Based Comparison Between the Posterior and Direct Lateral Approaches to Total Hip Arthroplasty: A Single-Center Experience

Introduction Many approaches to performing total hip arthroplasty (THA) exist, primarily due to an insufficient amount of research that would favor one approach over the other. This study aimed to compare the risk of nerve injury, dislocation, Trendelenburg gait, and stem malposition between the direct lateral and posterior approaches to THA. Methods The study was a retrospective cohort study, and it was conducted in King Abdulaziz Medical City. It was directed toward adult patients who underwent THA from November 1, 2003, to November 1, 2018. All figures were obtained through the BESTCare system (ezCareTech, Saudi Arabia). Categorical variables were presented as frequencies and proportions. Quantitative variables were measured as mean and standard deviation. Fisher's exact test was used to compare the risk of complications between the two approaches. Results The posterior approach displayed a greater risk of stem malposition (p< 0.001) when compared with the direct lateral approach. However, neither approach showed a higher risk of dislocation, nerve injury, or Trendelenburg gait. Conclusions A higher risk of stem malposition was observed in the posterior approach, and there were no remarkable variances between the two approaches in the risk of dislocation, nerve injury, and Trendelenburg gait. Until more meticulous nationwide studies are available to provide evidence that would favor an approach over the other, the choice of surgical approach for THA remains to depend on the patient's characteristics and the surgeon's prior experience. Regardless of the approach, preoperative, intraoperative, and postoperative factors that increase the risk of complications should also be identified and addressed adequately.

A Specific Capsular Repair Technique Lowered Early Dislocations in Primary Total Hip Arthroplasty Through a Posterior Approach

BACKGROUND

Dislocation is a challenging problem after total hip arthroplasty (THA). We sought to evaluate the incidence of early dislocation with 2 different posterior repair techniques after THA using a posterior approach.

METHODS

From September of 2008 to August of 2019, we evaluated 841 THAs performed by a single surgeon using a posterior approach. Before November of 2015, the capsule was repaired to the greater trochanter (group 1, 605 patients). Starting November 2015, the posterior capsule was repaired in a side-to-side fashion (direct soft-tissue repair) (group 2, 236 patients). There was a mean follow-up of 31.1 months (range, 2.5-122.5 months). A multivariable logistic regression model was constructed to assess the impact of baseline patient and operative factors on the dislocation rate.

RESULTS

There were 22 dislocations, all of which occurred in group 1. There were no dislocations in group 2. After adjusting for patient and operative factors, the direct soft-tissue repair had a large impact on the overall multivariable model as indicated by its effect likelihood ratio of 10.33 (P = .001); however, the odds ratio was not calculable for this factor, given that there were no dislocations in hips with direct soft-tissue repair. Increasing age was associated with an increased odds of dislocation (odds ratio, 1.04, P = .017), with an effect likelihood ratio of 6.25 (P = .012).

CONCLUSIONS

Switching from a capsular repair to the greater trochanter to a side-to-side capsular repair was associated with a decreased rate of dislocation in primary THA through a posterior approach.

Do hip precautions after posterior-approach total hip arthroplasty affect dislocation rates? A systematic review of 7 studies with 6,900 patients

Background and purpose - Hip precautions limiting flexion, adduction, and internal rotation have been prescribed traditionally to minimize dislocation rates following THA. We assessed the prevalence of hip dislocation following posterior approach total hip arthroplasty without postoperative hip precautions. Methods - A systematic review of multiple medical databases was performed using the PRISMA guidelines and checklist. All clinical outcome studies that reported dislocation rates and postoperative instructions following posterior approach, primary surgery, published within the last 6 years, were included. Results - 6,900 patients were included from 7 Level I-IV studies, with 3,517 treated with and 3,383 without precautions. There was no statistically significant difference in the rates of dislocation between groups (2.2% in restricted group vs. 2.0% in unrestricted group). All but 1 study demonstrated no statistically significant differences in patient-reported outcome scores between restricted and unrestricted groups, including those pertaining to return to function, confidence, and pain. Interpretation - The review found no impact on dislocation rates following total hip arthroplasty performed through a posterior approach, regardless of the use of hip precautions. We also found no impact of the prescription of hip precautions on patient-reported outcome scores.

Protrusion of a ceramic femoral head through the acetabular metallic cup in total-hip arthroplasty: A case report

RATIONALE

Dislocation, wear, metallosis, and implant loosening are well-known complications of a failed total-hip arthroplasty (THA), and acetabular liner dissociation is an uncommon but catastrophic complication. To our knowledge, this is the first description of metallosis due to acetabular liner dissociation, but not presenting as a result of wear of a metal-on-metal articulation and a polyethylene liner of other articulation.

PATIENT CONCERNS

We described a 61-year-old man who had a 2-year history of pain in the right groin region after THA. Postoperative period of primary THA was uneventful. However, he did not undergo postoperative follow-up, and often participated in strenuous sports activities including mountain climbing and long-distance running.

DIAGNOSIS

Radiographs demonstrated superior subluxation of the femoral head and direct articulation and abrasion wear of the ceramic femoral head on the cup. Preoperative laboratory data revealed no signs of infection.

INTERVENTIONS

We performed revision THA using a direct lateral approach with ceramic-on-ceramic hip prosthesis.

OUTCOMES

Postoperatively, the patient wore a hip orthosis for 6 weeks to prevent dislocation but was allowed full weight bearing. At 1-year follow-up, there was no recurrence of hip pain.

LESSONS

Wear of THA components can result in catastrophic failure of the implants and significant soft-tissue metallosis. Therefore, regular postoperative follow-up is necessary for early intervention, even in those with asymptomatic hips.

Can Total Hip Arthroplasty for Hip Fracture Be Safely Performed by Trainees? A Retrospective Cohort Study

BACKGROUND

No research is available comparing trainee and consultant outcomes for total hip arthroplasty (THA) for hip fracture. The aim of our study is to determine whether trainee-performed and consultant-performed THA produced equivalent radiological outcomes and complication rates for this patient cohort.

METHODS

We performed a retrospective cohort study at our institution, with inclusion of patients who underwent a primary THA for hip fracture between March 30, 2017 and February 07, 2019. Relevant perioperative and outcome data were collected through electronic records. Radiological outcomes were assessed by 2 independent reviewers. Follow-up was performed until August 07, 2019.

RESULTS

Eighty-seven patients were included in the study. The mean length of follow-up was 13 months (range, 6-29). Forty-three patients underwent consultant-led operations and 44 underwent trainee-performed (ST3-ST8) operations under consultant supervision. There were no significant differences between the 2 groups regarding complication risk (no recorded dislocation, infection requiring reoperation, revision or 30-day mortality in either group). There were also no significant differences between trainees and consultants regarding the radiological outcomes of mean acetabular component inclination (37.2° vs 36.7°, respectively, P = .74); offset difference (+7.1 mm vs +7.2 mm, respectively, P = .91); leg length difference (+6.4 mm vs +5.7 mm, respectively, P = .56); and barrack grade for femoral cement mantle.

CONCLUSION

This study suggests that radiological and safety outcomes for trainees performing THA for hip fracture with appropriate supervision are equivalent to consultant surgeons. However, given the low event rate of complications, a larger study is required to determine whether there is any statistically significant difference.