A Comparison of Risk of Dislocation and Cause-Specific Revision Between Direct Anterior and Posterior Approach Following Elective Cementless Total Hip Arthroplasty

Outcomes of Total Hip Arthroplasty in Patients Who Have Ehlers-Danlos Syndrome: A Matched Cohort Study

BACKGROUND

Total hip arthroplasty (THA) is an effective surgical treatment for severe osteoarthritis of the hip. While THA is considered a reliable and safe procedure, outcome data on patients who have Ehlers-Danlos syndrome (EDS) is limited. The purpose of this study was to compare rates of postoperative complications after primary THA in patients who have EDS against matched controls.

METHODS

A large national database was searched to identify patients who underwent THA between 2009 and 2020. Patients younger than 18 years, those who have a history of prior THA, and those undergoing THA for a hip fracture were excluded from analysis. Propensity score matching was utilized to match patients who had EDS with patients who did not have EDS at a 1:4 ratio. Rates of medical and surgical complications at 90 days and 2 years were queried and compared between the cohorts using multivariable logistic regression. We identified 118 patients who had EDS and underwent primary THA, who were then matched with 418 controls.

RESULTS

At 90 days, the EDS cohort had greater rates of dislocation (8.5 versus 3.8%, P = 0.038). At 2 years, the EDS cohort had greater odds of dislocation (OR [odds ratio] 2.47, P = 0.018), aseptic loosening (OR 6.91, P = 0.002), and aseptic revision (OR 2.66, P = 0.02).

CONCLUSIONS

Patients who have EDS possess significantly higher odds of complications after THA compared to matched controls, including dislocation, aseptic loosening, and aseptic revision. Careful surgical planning in these patients should be made to prevent dislocation and potentially minimize the risk of other prosthesis-related complications leading to revision.

Does Surgical Approach Affect Dislocation Rate After Total Hip Arthroplasty in Patients Who Have Prior Lumbar Spinal Fusion? A Retrospective Analysis of 16,223 Cases

BACKGROUND

Lumbar spinal fusion (LSF) is a risk factor for dislocation following total hip arthroplasty (THA). The effect of the surgical approach on this association has not been investigated. This study examined the association between the surgical approach and dislocation following THA in patients who had prior LSF.

METHODS

We retrospectively reviewed 16,223 primary elective THAs at our institution from June 2011 to September 2022. Patients who had LSF prior to THA were identified using International Classification of Diseases (ICD) codes. Patients were stratified by LSF history, surgical approach, and intraoperative robot or navigation use to compare dislocation rates. There were 8,962 (55.2%) posterior, 5,971 (36.8%) anterior, and 1,290 (8.0%) laterally based THAs. Prior LSF was identified in 323 patients (2.0%). Binary logistic regressions were used to assess the association of patient factors with dislocation risk.

RESULTS

There were 177 dislocations identified in total (1.1%). In nonadjusted analyses, the dislocation rate was significantly higher following the posterior approach among all patients (P = .003). Prior LSF was associated with a significantly higher dislocation rate in all patients (P < .001) and within the posterior (P < .001), but not the anterior approach (P = .514) subgroups. Multivariate regressions demonstrated anterior (OR [odds ratio] = 0.64, 95% CI [confidence interval] 0.45 to 0.91, P = .013), and laterally based (OR = 0.42, 95% CI 0.18 to 0.96, P = .039) approaches were associated with decreased dislocation risk, whereas prior LSF (OR = 4.28, 95% CI 2.38 to 7.69, P < .001) was associated with increased dislocation risk. Intraoperative technology utilization was not significantly associated with dislocation in the multivariate regressions (OR = 0.72, 95% CI 0.49 to 1.06, P = .095).

CONCLUSIONS

The current study confirmed that LSF is a significant risk factor for dislocation following THA; however, anterior and laterally based approaches may mitigate dislocation risk in this population. In multivariate analyses, including surgical approach, LSF, and several perioperative variables, intraoperative technology utilization was not found to be significantly associated with dislocation risk.

Early Prosthetic Hip Dislocation: Does the Timing of the Dislocation Matter?

BACKGROUND

Early dislocation following total hip arthroplasty (THA) is a common reason for revision. The purpose of this study was to determine if the acuity of the dislocation episode affects the risk of revision surgery.

METHODS

A retrospective review of a national, all-payer administrative database comprised of claims from 2010 to 2020 was used to identify patients who had a prosthetic hip dislocation at various postoperative time intervals (0 to 7, 7 to 30, 30 to 60, and 60 to 90 days). Of the 45,352 primary unilateral THA patients who had sufficient follow-up, there were 2,878 dislocations within 90 days. Dislocators were matched 1:1 based on age, sex, and a comorbidity index with a control group (no dislocation). Demographics, surgical indications, comorbidities, ten-year revision rates, and complications were compared among cohorts. Multivariable logistic regression analysis was performed to identify risk factors for revision THA following early dislocation.

RESULTS

Among matched cohorts, dislocation at any time interval was associated with significantly increased odds of subsequent 10-years revision (OR [odds ratio] = 25.60 to 33.4, P < .001). Acute dislocators within 7 days did not have an increased risk of all cause revisions at 10 years relative to other early dislocators. Revision for indication of instability decreased with time to first dislocation (<7 days: 85.7% versus 60 to 90 days: 53.9%). Primary diagnoses of posttraumatic arthritis (OR = 2.53 [1.84 to 3.49], P < .001), hip fracture (OR = 3.8 [2.53 to 5.72], P < .001), and osteonecrosis (OR = 1.75 [1.12 to 2.73], P = .010) were most commonly associated with revision surgery after an early dislocation.

CONCLUSIONS

Dislocation within 90 days of THA is associated with increased odds of subsequent revision. Early dislocation within 7 days of surgery has similar all cause revision-free survivorship, but an increased risk of a subsequent revision for instability when compared to patients who dislocated within 7 to 90 days.

Surgical Approach Does Not Influence Instability Risk in Revision Total Hip Arthroplasty

BACKGROUND

Although the direct anterior (DA) approach has increased in popularity for primary total hip arthroplasty (THA), there is limited evidence regarding its use for revision THA. It is unknown whether the dislocation benefit seen in the primary setting translates to revision cases.

METHODS

This retrospective review compared the dislocation rates of revision THA performed through DA versus postero-lateral (PL) approaches at a single institution (2011 to 2021). Exclusion criteria included revision for instability, ≥ 2 prior revisions, approaches other than DA or PL, and placement of dual-mobility or constrained liners. There were 182 hips in 173 patients that met the inclusion criteria. The average follow-up was 6.5 years (range, 2 to 8 years).

RESULTS

There was a trend toward more both-component revisions being performed through the PL approach. There were no differences in dislocation rates between the DA revision and PL revision cohorts, which were 8.1% (5 of 72) and 7.5% (9 of 120), respectively (P = .999). Dislocation trended lower when the revision approach was discordant from the primary approach compared to cases where primary and revision had a concordant approach (4.9 versus 8.5%), but this was not statistically significant (P = .740). No significant differences were found in return to operating room, 90-day emergency department visits, or 90-day readmissions. However, the length of stay was significantly shorter in patients who had DA revisions after a primary PL procedure (P = .021).

CONCLUSIONS

Dislocation rates following revision THA did not differ between the DA and PL approaches irrespective of the primary approach. Surgeons should choose their revision approach based on their experience and the specific needs of the patient.

A Randomized Clinical Trial of Direct Anterior Versus Mini-Posterior Total Hip Arthroplasty: Small, Early Functional Differences Did Not Lead to Meaningful Clinical Differences at 7.5 Years

BACKGROUND

Our previously reported randomized clinical trial of direct anterior approach (DAA) versus mini-posterior approach (MPA) total hip arthroplasty showed slightly faster initial recovery for patients who had a DAA and no differences in complications or clinical or radiographic outcomes beyond 8 weeks. The aims of the current study were to determine if early advantages of DAA led to meaningful clinical differences beyond 5 years and to identify differences in midterm complications.

METHODS

Of the 101 original patients, 93 were eligible for follow-up at a mean of 7.5 years (range, 2.1 to 10). Clinical outcomes were compared with Harris Hip, 12-Item Short Form Health Survey, and Hip Disability and Osteoarthritis Outcomes Scores (HOOS) scores and subscores, complications, reoperations, and revisions.

RESULTS

Harris Hip scores were similar (95.3 ± 6.0 versus 93.5 ± 10.3 for DAA and MPA, respectively, P = .79). The 12-Item Short Form Health Survey physical and mental scores were similar (46.2 ± 9.3 versus 46.2 ± 10.6, P = .79, and 52.3 ± 7.1 versus 55.2 ± 4.5, P = .07 in the DAA and MPA groups, respectively). The HOOS scores were similar (97.4 ± 7.9 versus 96.3 ± 6.7 for DAA and MPA, respectively, P = .07). The HOOS quality of life subscores were 96.9 ± 10.8 versus 92.3 ± 16.0 for DAA and MPA, respectively (P = .046). No clinical outcome met the minimally clinically important difference. There were 4 surgical complications in the DAA group (1 femoral loosening requiring revision, 1 dislocation treated closed, and 2 wound dehiscences requiring debridement), and 6 surgical complications in the MPA group (3 dislocations, 2 treated closed, and 1 revised to dual mobility; 2 intraoperative fractures treated with a cable; and 1 wound dehiscence treated nonoperatively).

CONCLUSIONS

At a mean of 7.5 years, this randomized clinical trial demonstrated no clinically meaningful differences in outcomes, complications, reoperations, or revisions between DAA and MPA total hip arthroplasty.

LEVEL OF EVIDENCE

IV.

Intramedullary Total Femur via a Direct Anterior Approach for Complex Revision Total Hip and Knee Arthroplasty

Total femur replacement is a well-recognized salvage procedure and an alternative to hip disarticulation in patients with massive femoral bone loss. Compared to conventional total femur replacement, intramedullary total femur (IMTF) requires less soft tissue dissection and preserves femoral bone stock and soft-tissue attachments. Despite these advantages, patients can still anticipate compromised functional outcomes and high complication rates following IMTF. Prior studies describe IMTF with the patient positioned laterally and utilizing posterior or anterolateral approaches to the hip. We describe our IMTF technique performed via the direct anterior approach in the supine position. In our experience, this is an effective method, with potential benefits including intraoperative limb length and rotational assessment, use of fluoroscopy, more convenient exposure of the knee, and potential lower rates of hip instability.

Does Approach Matter in Robotic-Assisted Total Hip Arthroplasty? A Comparison of Early Reoperations Between Direct Anterior and Postero-Lateral Approach

BACKGROUND

There is no consensus on whether direct anterior approach (DAA) or postero-lateral approach (PLA) total hip arthroplasty (THA) confers a lower risk of postoperative complications. Robotic assistance in THA results in a more consistently accurate component position compared to manual THA. The objective of this study was to compare rates of dislocation, reoperation, revision, and patient-reported outcome measures between patients undergoing DAA and PLA robotic-assisted primary THA.

METHODS

We identified 2,040 consecutive robotic-assisted primary THAs performed for primary osteoarthritis, using DAA (n = 497) or PLA (n = 1,542) between 2017 and 2020. The mean follow-up was 18 months. Kaplan-Meier analysis estimated survivorship free of dislocation, reoperation, and revision. Achievement of patient acceptable symptom state and minimum clinically important difference were used to compare changes in the Hip Disability and Osteoarthritis Outcome Score, Joint Replacement (HOOS JR) and Visual Analog Scale.

RESULTS

Dislocation was rare in this series (14 in 2,040, 0.7%), including 1 of 497 (0.2%) in the DAA cohort and 13 of 1,542 (0.8%) in the PLA cohort (P = .210). There was no difference in 2-year reoperation-free survivorship (97.8 versus 98.6%, P = .59) or revision-free survivorship (98.8 versus 99.0%, P = .87) at any time point. After controlling for age, sex, and body mass index, there was no difference in dislocation, reoperation, or revision. At 6-week follow-up, after controlling for age, sex, and body mass index, patients in the DAA cohort had higher odds of achieving HOOS JR minimum clinically important difference (odds ratio = 2.01, P = .012) and HOOS JR patient acceptable symptom state (odds ratio = 1.72, P = .028). There were no differences in patient-reported outcome measures by 3 months.

CONCLUSIONS

For robotic-assisted primary THA, DAA may confer enhanced early (<6 weeks) functional recovery compared to the PLA, but there was no significant difference in postoperative dislocation, reoperation, or revision rates.

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.

Extended offset stems are infrequently required in anterior approach total hip arthroplasty and low usage does not compromise stability

INTRODUCTION

Extended offset (EO) stems are commonly used in posterior approach (PA) total hip arthroplasty (THA), but usage rates and complications are not well studied with anterior approach (AA) THA. This study evaluated usage rates, radiographic outcomes and complications following AA THA between patients receiving EO stems and a matched cohort receiving standard offset (SO) stems.

MATERIALS AND METHODS

This retrospective review evaluated 1515 consecutive AA THA performed between 2014 and 2021. The recent 100 EO were included in radiographic and complication analysis and were matched to 100 SO stems based on stem size, procedure (unilateral/bilateral), sex, body mass index (BMI), and age. Data collection included patient demographics; pre- and postoperative radiographic measurements of leg length difference (LLD) and global hip offset difference (GHOD); and complications within 1 year. Independent t-tests and Chi-squared analyses compared EO and SO groups.

RESULTS

EO was utilized in 8% of all AA THA. Despite matching procedures, the distribution of racial groups was different between EO and SO groups, respectively: Caucasian (75% vs. 43%), Asian (12% vs. 35%), Native Hawaiian/Pacific Islander (NHPI) (9% vs. 13%), and other (4% vs. 9%) (p < 0.001). No fractures, dislocations, or revisions occurred within 1 year after surgery in either group. One deep infection was noted in the SO group. The proportions of patients following surgery who had a GHOD < 6 mm (76% vs. 82%; p = 0.193) and LLD < 6 mm (81% vs. 86%; p = 0.223) were not significantly different between EO and SO groups, respectively.

CONCLUSIONS

Prioritizing hip symmetry over stability results in a high proportion of patients achieving hip symmetry without high usage of EO stems in AA THA. Furthermore, low use of EO stems did not result in increased dislocations. Due to racial anatomical differences, Caucasian patients required EO stems to achieve hip symmetry more frequently than Asian and NHPI patients.

Can Dual Mobility Cups Reduce Revision and Dislocation Risks? An Analysis of 107,528 Primary Total Hip Arthroplasties in the United States

BACKGROUND

Dual mobility acetabular cups (DMC) were designed to increase the effective femoral head size and improve stability with the goal of reducing revision risk at the potential cost of polyethylene thickness. We sought to evaluate revision risk following primary elective total hip arthroplasty with DMC compared to highly cross-linked polyethylene (XLPE).

METHODS

A cohort study was conducted using data from a Kaiser Permanente's total joint arthroplasty registry. Patients ≥18 years who underwent primary elective total hip arthroplasty using DMC, unipolar Metal-on-XLPE (MoXLPE), or unipolar Ceramic-on-XLPE (CoXLPE) were identified (2010 to 2021). The final sample comprised 2,219 DMC, 48,251 MoXLPE, and 57,058 CoXLPE. Multiple Cox proportional hazard regressions were used to evaluate aseptic revision and any dislocation regardless of revision within 6 years follow-up.

RESULTS

In adjusted analyses, no differences in aseptic revision risk were observed for MoXLPE (hazard ratio [HR] = 1.04, 95% confidence interval [CI] = 0.72 to 1.51) or CoXLPE (HR = 0.98, 95% CI = 0.69 to 1.40) compared to DMC. No differences in dislocation risk were observed for MoXLPE (HR = 1.42, 95% CI = 0.93 to 2.15) or CoXLPE (HR = 1.25, 95% CI = 0.84 to 1.87) compared to DMC.

CONCLUSIONS

In a US-based cohort, 6-year aseptic revision risk of DMC was similar to metal or ceramic femoral head unipolar constructs. Furthermore, no difference in dislocation risk was observed. Continued longer-term follow-up may reveal if there is a reduced risk of dislocation that comes at the cost of increased late revision.

LEVEL OF EVIDENCE

Level III.

Total Hip Arthroplasty Following Operative Fixation of Acetabular Fracture: A Contemporary Series

BACKGROUND

Total hip arthroplasty (THA) is the operation of choice for salvage of post-traumatic arthritis following acetabular fracture. While high failure rates have been reported for these procedures, existing literature reports mainly on historical implant designs and techniques. We aimed to describe implant survivorships, complications, radiographic results, and clinical outcomes of contemporary THA following prior open reduction internal fixation (ORIF) of an acetabular fracture.

METHODS

We identified 104 patients undergoing THA following prior ORIF of an acetabular fracture from 2000 to 2015 via our institutional total joint registry. Mean age at THA was 50 years (range, 18 to 79 years), 71% were men, and mean body mass index was 27 (range, 18 to 52). All patients were implanted with uncemented acetabular components, and 89% had uncemented stems. Some hardware from prior fixation was retained in 94% of cases. Mean follow-up was 10 years (range, 2 to 21 years).

RESULTS

The 10-year survivorships free of any revision and any reoperation were 98% and 97%, respectively. There were 4 revisions: 1 each for psoas tendonitis, dislocation, acetabular aseptic loosening, and periprosthetic joint infection. There were 9 complications that did not lead to reoperation: 5 dislocations, 2 periprosthetic femur fractures, 1 sciatic nerve palsy, and 1 case of symptomatic heterotopic ossification. All unrevised components appeared radiographically well-fixed. Mean Harris Hip Score improved from mean 50 preoperatively to mean 82 at 5 years (P < .001).

CONCLUSIONS

In this series of contemporary THAs following prior acetabular fracture ORIF, revision-free survivorship was excellent with only a single case of acetabular aseptic loosening. These results are encouraging and suggest that contemporary implants and techniques have notably improved on historic results.

LEVEL OF EVIDENCE

Therapeutic, Level IV.

Monobloc dual-mobility acetabular component versus a standard single-mobility acetabular component

Aims

The benefit of a dual-mobility acetabular component (DMC) for primary total hip arthroplasties (THAs) is controversial. This study aimed to compare the dislocation and complication rates when using a DMC compared to single-mobility (SM) acetabular component in primary elective THA using data collected at a single centre, and compare the revision rates and survival outcomes in these two groups.

Methods

Between 2010 and 2019, 2,075 primary THAs using either a cementless DM or SM acetabular component were included. Indications for DMC were patients aged older than 70 years or with high risk of dislocation. All other patients received a SM acetabular component. Exclusion criteria were cemented implants, patients treated for femoral neck fracture, and follow-up of less than one year. In total, 1,940 THAs were analyzed: 1,149 DMC (59.2%) and 791 SM (40.8%). The mean age was 73 years (SD 9.2) in the DMC group and 57 years (SD 12) in the SM group. Complications and revisions have been analyzed retrospectively.

Results

The mean follow-up was 41.9 months (SD 14; 12 to 134). There were significantly fewer dislocations in the DMC group (n = 2; 0.17%) compared to the SM group (n = 8; 1%) (p = 0.019). The femoral head size did not influence the dislocation rate in the SM group (p = 0.702). The overall complication rate in the DMC group was 5.1% (n = 59) and in the SM group was 6.7% (n = 53); these were not statistically different (p = 0.214). No specific complications were attributed to the use of DMCs. In the DMC group, 18 THAs (1.6%) were revised versus 15 THAs in the SM group (1.9%) (p = 0.709). There was no statistical difference for any cause of revisions in both groups. The acetabular component aseptic revision-free survival rates at five years were 98% in the DMC group and 97.3% in the SM group (p = 0.780).

Conclusion

The use of a monobloc DMC had a lower risk of dislocation in a high-risk population than SM component in a low-risk population at the mid-term follow-up. There was no significant risk of component-specific complications or revisions with DMCs in this large cohort.

Postoperative lymphedema after primary total hip arthroplasty: prospective analysis of bikini incision-type direct anterior approach versus established standard approaches

BACKGROUND

Minimally invasive approaches to the hip joint for total hip arthroplasty such as the DAA ("Direct Anterior Approach with bikini incision") are increasingly utilized. According to the literature, this approach is more muscle-sparing, results in less postoperative pain, and achieves higher patient satisfaction. The existence of postoperative lymphedema after hip arthroplasty is hardly considered. The aim of this paper is to contribute to the evaluation of the different access methods related to postoperative lymphedema and their functional outcomes.

METHODS

This is a prospective non-randomized study at an orthopedic specialist clinic in Northern Europe. The surgeons that performed the arthroplasties are high-volume surgeons in private practice affiliated to the clinic. The study included 188 patients with primary hip arthroplasty in a 1:1 ratio (DAA: standard accesses (posterior, transgluteal, and anterolateral access)). Epidemiologic data, Harris Hip Score, Oxford Hip Score, European Quality of Life 5, and Visual Analog Scale were collected preoperatively on admission day, 3rd and 5th postoperative day, and follow-up after 1 year. Furthermore, the range of motion, gait, and ability to climb stairs, as well as the presence of hypesthesia were assessed. To evaluate the edema situation, both legs were measured on the 3rd and 5th postoperative day. The prescription of manual lymphatic drainage and remaining swelling conditions 1 year postoperatively were recorded.

RESULTS

For each group, 94 patients with a mean age of 61.7 years (DAA 60.7 and standard access 62.6) were included. All but one patient in the DAA group showed postoperative lymphedema (n: 93/94; 98.9%). In the standard surgery group, only n: 37/94 (39.4%) showed swelling symptoms requiring treatment. After 1 year, lymphedema persisted in 20 patients in the DAA group and 0 patients in the standard-OR group. Hypesthesia at the ventral thigh persisted in 16/94 (= 17%) patients of the DAA group versus 0/94 patients of the standard group after 12 months. Of these 16 cases, 10 had concomitant edema (62.5%). The DAA showed better results than the standard accesses in terms of Oxford Hip Score (p < 0.05) and ability to climb stairs (p < 0.05). In contrast, the Visual Analog Scale and patient quality of life results showed no significant difference (p > 0.05).

CONCLUSION

The present study demonstrated the increased incidence of postoperative lymphedema in patients operated on via DAA access using a Bikini-type skin incision. In the follow-up, significantly more hypesthesia of the ventral thigh occurred in the DAA group. Otherwise, the DAA proved to be superior to the standard approaches from a functional point of view at short-term follow-up. Future research is needed to compare the horizontally oblique to the longitudinal oblique skin incision technique in direct anterior hip surgery regarding the above-mentioned adverse effects found in this study.

Periprosthetic fracture following anterior approach or dislocation after posterior approach: which one is the lesser evil?

INTRODUCTION

The most common approaches in total hip arthroplasty (THA) have different complication profiles; anterior-approach (AA-THA) has an increased risk of periprosthetic fractures (PPF); posterior-approach (PA-THA) is associated with higher dislocation risk. However, the relative severity of one versus the other is unknown. This study aims to compare outcome of patients who suffered PPF after AA-THA with those that sustained dislocation after PA-THA.

METHODS

This is a retrospective, single-center, multi-surgeon, consecutive case-series of primary THA patients. In a cohort of 9867 patients who underwent THA, 79 fulfilled the approach-specific, post-operative complication criteria, of which 44 were PPF after AA-THA and 35 with dislocation after PA-THA (age 67.9 years (range: 38.0-88.1), 58.2% women). Outcome included complication- and revision- rates, and patient-reported outcomes including Oxford Hip Score (OHS).

RESULTS

At 5.8 years follow-up (range: 2.0-18.5), reoperation was more common in the dislocation after PA-THA group (23/35 vs. 20/44; p = 0.072). Change of surgical approach occurred in 15/20 of patients with PPF after AA-THA, but none in those with dislocation after PA-THA. Following re-operation, complication rate was greater in the PPF group (9/20 vs. 4/23; p = 0.049). At latest follow-up, OHS were superior in the PPF after AA-THA group [42.6 (range: 25.0-48.0) vs. 36.6 (range: 21.0-47.0); p = 0.006].

CONCLUSION

Dislocation following PA-THA is more likely to require revision. However, PPF following AA-THA requires more often a different surgical approach and is at higher risk of complications. Despite the increased surgical burden post-operative PROMs are better in the peri-prosthetic fracture group, especially in cases not requiring reoperation.

LEVEL OF EVIDENCE

III, case-control study.

Early Practice All-Cause Complications for Fellowship-Trained Anterior Hip Surgeons Are Not Increased When Compared to "Gold Standard" Experienced Posterior Approach Surgeons

BACKGROUND

Increased complication rates have been reported during the learning curve for direct anterior approach (DAA) total hip arthroplasty (THA). However, emerging literature suggests that complications associated with the learning curve may be substantially reduced with fellowship training.

METHODS

Our institutional database was queried to identify 2 groups: (1) 600 THAs comprised of the first 300 consecutive cases performed by 2 DAA fellowship-trained surgeons; and (2) 600 posterolateral approach (PA) THAs, including the most recent 300 primary cases performed by 2 experienced PA surgeons. All-cause complications, revision rates, reoperations, operative times, and transfusion rates were evaluated.

RESULTS

Comparing DAA and PA cases, there were no significant differences in rates of all-cause complications (DAA = 18, 3.0% versus PA = 23, 3.8%; P = .43), periprosthetic fractures (DAA = 5, 0.8% versus PA = 10, 1.7%; P = .19), wound complications (DAA = 7, 1.2% versus PA = 2, 0.3%; P = .09), dislocations (DAA = 2, 0.3% versus PA = 8, 1.3%, P = .06), or revisions (DAA = 2, 0.3% versus PL = 5, 0.8%; P = .45) at 120 days postoperatively. There were 4 patients who required reoperation for wound complications, all within the DAA group (DAA = 4, 0.67% versus PA = 0; P = .045). Operative times were shorter in the DAA group (DAA <1.5 hours = 93% versus PA <1.5 hours = 86%; P < .01). No blood transfusions were given in either group.

CONCLUSION

In this retrospective study, DAA THAs performed by fellowship-trained surgeons early in practice were not associated with higher complication rates compared to THAs performed by experienced PA surgeons. These results suggest that fellowship training may allow DAA surgeons to complete their learning curve period with complication rates similar to experienced PA surgeons.

Femoral head size and surgical approach affect dislocation and overall revision rates in total hip arthroplasty: up to 9-year follow-up data of 269,280 procedures in the Dutch Arthroplasty Register (LROI)

BACKGROUND

Femoral head size and surgical approach might affect the revision rate for dislocation and for any other reason after total hip arthroplasty (THA). We penetrated this question based on registry data with up to 9-year follow-up.

METHODS

269,280 primary THAs documented in the Dutch Arthroplasty Registry (LROI) between 2007 and 2019 were included. Revision rates were calculated by competing risk analyses. Multivariable Cox proportional hazard regression ratios (HR) were used for comparison.

RESULTS

Revisions for dislocation were rare. They were more frequent after posterolateral (1.4% [95% CI, 1.3-1.5]), compared to straight lateral (0.6% [95% CI, 0.5-0.7]), anterolateral (0.6% [95% CI, 0.5-0.7]) and anterior (0.4% [95% CI, 0.3-0.5]) approach. Larger femoral head size decreased the dislocation revision risk: 1.4% [95% CI, 1.3-1.5) for 22-28-mm heads; 0.9% (95% CI, 0.8-1.0) for 32-mm heads; 0.6% (95% CI, 0.6-0.7) for 36-mm heads. For the anterior approach, the HR for both revision for dislocation (0.3, 95% CI, 0.3-0.4) and any other reason (0.8, 95% CI, 0.8-0.9) were lowest compared to other approaches including posterolateral (HR 1). Revision risk for any other reason was highest with anterolateral (HR 1.3 (95% CI, 1.2-1.4)) and straight lateral approach (1.1 [95% CI, 1.0-1.2]).

CONCLUSIONS

The anterior approach might reduce revision rates for both dislocation and all cause revision. Posterolateral approach is associated with a higher risk of dislocation revision but has a lower risk of any other revision. Increasing femoral head size up to 36 mm reduces revision for dislocation and improves overall revision rates for all approaches.

Acute total hip replacement by direct anterior approach combined with intrapelvic fixation for geriatric acetabular fracture of the anterior column

Management of anterior column acetabular fracture in the elderly is challenging. Open reduction and internal fixation do not allow early weight bearing and are associated with a high risk of failure compared to younger patients. Therefore, acute fixation and total hip arthroplasty may be an option. This technical note describes a combined procedure: anterior intrapelvic approach for fracture fixation and a direct anterior approach to the hip for THR. Fracture reduction and arthroplasty were achievable in all five patients. The mean operative time was 289min, and the mean blood loss was 2120mL. At short term, no complication was noticed. Combining these two "muscle-sparing" approaches could help manage anterior column fractures in elderly patients. Level of evidence: IV.

Total Hip Arthroplasty: An Update on Navigation, Robotics, and Contemporary Advancements

While total hip arthroplasty (THA) remains effective for improvement of pain and function in patients with osteoarthritis and avascular necrosis, there remain areas of continued pursuit of excellence, including decreasing rates of dislocation, leg length discrepancy, implant loosening, and infection. This review article covers several bearing surfaces and articulations, computer-assisted navigation and robotic technology, and minimally invasive surgical approaches that have sought to improve such outcomes. Perhaps the most significant improvement to THA implant longevity has been the broad adoption of highly cross-linked polyethylene, with low wear rates. Similarly, navigation and robotic technology has proven to more reproducibly achieve intraoperative component positioning, which has demonstrated clinical benefit with decreased risk of dislocation in a number of studies. Given the projected increase in THA over the coming decades, continued investigation of effective incorporation of technology, soft tissue-sparing approaches, and durable implants is imperative to continued pursuit of improved outcomes in THA.

Results of the transition from posterolateral to anterior minimally invasive approach for total hip arthroplasty

BACKGROUND

The anterior minimally invasive (AMI) approach reduces soft tissue damage, risk of dislocation and enhances recovery, but it is associated with certain complications. The aim of this study is to compare the outcomes of patients who underwent total hip arthroplasty (THA) through posterolateral (PL) and AMI approaches performed by the same surgeon, in order to determine the learning curve associated with this new approach.

METHODS

This retrospective cohort study included patients who underwent THA via PL and AMI approach between 2017 and 2022, with a minimum follow-up of 1 year. Hip fracture and oncologic patients were excluded. Demographic variables, functional scores and perioperative complications were assessed. A bivariate analysis was performed to identify differences between groups.

RESULTS

Data of 124 AMI and 120 PL patients were analyzed. Demographic characteristics among groups were homogeneous. Functional outcomes at 3 months were superior for AMI (Oxford: 43 vs. 38; p < 0.05), no dislocations were identified (0% vs. 4.2%; p < 0.05) and no differences in the transfusion rate were found (6.5% AMI vs. 6.7% PL; p = 0.996). Infection rate was 4% for AMI and 3.4% for PL (p = 0.572). Surgical time was shorter for the PL approach, but the median surgical time of the last 25 AMI cases was shorter.

CONCLUSIONS

The AMI approach is an excellent alternative for patients requiring THA. Although surgical time and perioperative bleeding were greater during the learning curve, this approach offers improved functional outcomes and a lower dislocation rate, without significant differences in transfusion and infection outcomes, demonstrating that responsible innovation and safe implementation of new techniques is possible.

Clinical outcomes of DAA and related techniques in hip arthroplasty

Total hip arthroplasty (THA) has been one of the most successful surgical interventions in recent memory and is nicknamed by some the "Surgery of the Century". Over the past decade, there has been a drastic change in THA management with the rise of the direct anterior approach both globally and in the USA market. While many would remark that this has been driven by false marketing, it is clear that the direct anterior approach can be an effective and safe way to perform a THA.It is the goal of this review to highlight evidence of its outcomes and clinical advantages, in particular, how it can decrease dislocation, even in high-risk individuals, and result in faster recovery in the early postoperative period with decreased muscular inflammation. We will also highlight its major disadvantages, including but not limited to increased wound complications and risk for periprosthetic fracture. Hopefully, this review will provide up-to-date information on the current state of the direct anterior approach and provide recommendations on patients that would be optimal candidates for this technique.

Surgical approach had minor association with femoral stem migration in total hip arthroplasty: radiostereometric analysis of 61 patients after 5-year follow-up

BACKGROUND AND PURPOSE

Total hip arthroplasty (THA) is usually performed using 1 of 3 surgical approaches: direct lateral (DLA), posterior (PA), or anterior (AA). AA is different from DLA and PA owing to limited intraoperative visibility of the femoral canal. This could affect stem positioning and therefore migration. We aimed to perform an exploratory radiostereometric analysis (RSA) study with 3 groups for surgical approach assessing stem migration up to 5 years postoperatively.

PATIENTS AND METHODS

61 patients with unilateral osteoarthritis of the hip were included. 21 patients were allocated to the DLA, 20 to the PA, and 20 to the AA group. All patients received an uncemented, collarless, double-tapered, fully hydroxyapatite-coated Profemur Gladiator stem. Migration was measured with model-based RSA. Baseline RSA was on day 1 postoperatively. The follow-ups were at day 8, at 5 weeks, and at 3, 6, 12, 24, and 60 months after surgery. Generalized linear mixed models were used to analyze maximum total point motion (MTPM) migrations.

RESULTS

Group mean differences in MTPM were 0.4 mm (95% confidence interval [CI] -1.5 to 2.4) for DLA vs. PA, 1.1 mm (CI -1.0 to 3.3) for AA vs. DLA, and 1.6 mm (CI -0.8 to 3.9) for AA vs. PA, when adjusted for sex and age as covariates. 2 stems in the AA group had excessive early migration. For all stems the migrations occurred mainly within 5-week follow-up and then stabilized.

CONCLUSION

At 5-year follow-up, there were no statistically significant differences in stem migration associated with the 3 surgical approaches used in this study.

Total Hip Arthroplasty Learning Curves Based on Approach for New Fellowship-trained Surgeons

INTRODUCTION

There is concern that the direct anterior (DA) approach is associated with a steeper learning curve than the posterolateral (PL) approach in total hip arthroplasty (THA). The purpose of this study was to investigate if the learning curve is similar for newly trained arthroplasty fellowship-trained surgeons using the DA and PL approaches.

METHODS

The first 100 primary THA cases of six DA and PL fellowship-trained arthroplasty surgeons were identified and divided into 50 case cohorts. Demographics, indications for surgery, and 90-day Hip Society standardized complications were collected. Variables were analyzed using independent sample t tests, chi-square tests, or Fisher exact tests.

RESULTS

In total, there were 600 patients, and no notable differences were observed in revision surgeries, surgical complications, and total complications between the DA and PL groups. Both groups had lower revision surgery rates, surgical complications, and total complications during their second 50 cases. Higher revision surgeries, and surgical and total complication rates were observed among all surgeons during the first 50 cases.

DISCUSSION AND CONCLUSION

No differences were observed in the learning curve when comparing the DA and PL approach. With proper training, early-career surgeons can safely perform THA with similar complication rates regardless of the approach.

Total Hip Arthroplasty in Patients with Bilateral Upper-Limb Amelia: A Report of 2 Cases

CASE

We report two patients, a 43-year-old man and a 26-year-old woman, with bilateral absence of the upper extremity and severe hip osteoarthritis. The involved hip was the dominant extremity for both patients. Total hip arthroplasty (THA) was performed using a posterior approach with dual-mobility implants. Both patients report satisfactory outcomes including the ability to perform the significant range of motion required for daily activities such as toe-to-head motion.

CONCLUSION

In patients with extreme range of motion requirements such as those affected with bilateral upper-limb amelia, a posterior THA with a dual-mobility implant may be safely and successfully performed to treat disabling hip osteoarthritis.

Mean 16-Year Results of Total Hip Arthroplasty with Alumina Ceramic Femoral Heads on Highly Cross-Linked Polyethylene in Patients 50 Years or Less

BACKGROUND

Highly cross-linked polyethylene (HXLPE) is a widely used bearing surface in total hip arthroplasty (THA); long-term results in young patients are limited. We previously demonstrated excellent results in HXPLE on cobalt-chrome femoral heads at 15-year mean follow-up. The purpose of the present study was to investigate polyethylene wear rates, implant survivorships, wear-related revisions, and patient-reported outcomes (PROs) in a young patient cohort who had alumina ceramic on HXPLE coupling at an average 16-year follow-up.

METHODS

This was a retrospective study of 128 hips who underwent THA with HXLPE on alumina ceramic bearings between March 1, 2004, and April 15, 2007. Patient mean age was 38 years (range, 13 to 50). All THAs utilized HXPLE liners with alumina ceramic heads. The University of California, Los Angeles (UCLA) Activity Score and modified Harris Hip Scores (mHHS) were collected pre-operatively and at each follow-up. Martell Hip Analysis Suite was used for wear calculations.

RESULTS

At average 16 years (range, 13 to 18), aseptic revision survivorship was 93.3% and osteolysis/wear survivorship was 99.2%. The mean linear wear rate was 0.0191 millimeters (mm)/year and mean volumetric wear rate was 19.43 mm³/year, both of which were clinically undetectable. We observed excellent patient reported outcomes with a significant increase in mean mHHS (43.6 to 87.4, P <0.0001) and UCLA Activity Scores (4.0 to 6.0, P <0.0001). There were no statistically significant differences in PROs or wear rates between ceramic and cobalt-chrome groups.

CONCLUSION

At mean 16-year follow-up, young patients who had HXLPE on ceramic coupling had excellent wear properties, PROs, and acceptable survivorships.

Complication Rate after Primary Total Hip Arthroplasty Using the Posterior Approach and Enabling Technology: A Consecutive Series of 2,888 Hips

BACKGROUND

Total hip arthroplasty (THA) is a safe and effective procedure, however, complications such as dislocation, fracture, and infection still occur. It is still unclear whether the dislocation rate via the posterior approach (PA) is better, equal, or worse than the direct anterior approach. Our aim was to report the primary THA dislocation rate via the PA using enabling technology in a large consecutive series of patients.

METHODS

A retrospective cohort of 2,888 primary THAs were reviewed at a single, high volume, academic institution from January 2018 to September 2021. All patients underwent a THA by four fellowship-trained orthopaedic surgeons through the PA with enabling technology. Overall dislocation and readmission rates within 90 days and up to 3 years were analyzed.

RESULTS

Of the 2,888 procedures, a total of 39 patients had complications related to the surgery during the 3-year follow-up period. There were 10 patients (0.35%) who experienced a dislocation, with half undergoing surgical revision. Of the 39 patients who experienced complications, 37 (1.3%) were readmitted and 2 underwent revision during their hospital stay. Post-operative periprosthetic fractures were the most common cause for readmission and reoperation at a rate of 0.52 and 0.52%, respectively.

CONCLUSION

The dislocation rate of 0.35% is one of the lowest reported rates via the PA at a mean follow up of 2.1 years and is comparable to previously published rates using alternate approaches. Using contemporary THA with enabling technology, the PA is a reliable approach with respect to dislocation and complication rates after primary THA.

Revision risk by using the direct superior approach (DSA) for total hip arthroplasty compared with postero-lateral approach: early nationwide results from the Dutch Arthroplasty Register (LROI)

BACKGROUND AND PURPOSE

The direct superior approach (DSA) is a modification of the classic posterolateral approach (PLA) for total hip arthroplasty (THA), in which the iliotibial band and short external rotators are spared. The revision rate of the DSA has not been investigated previously using arthroplasty registry data. We examined the reasons and risk of revision of the DSA, compared with the direct anterior approach (DAA) and PLA.

PATIENTS AND METHODS

In this population-based cohort study we included 175,543 primary THAs performed between 2014 and 2020 (PLA, n = 117,576; DAA, n = 56,626; DSA, n = 1,341). Competing risk survival analysis and multivariable Cox proportional hazard analyses, adjusted for potential confounders, were performed.

RESULTS

After 3 years, crude revision rates due to any reason were 2.1% (95% confidence interval [CI] 1.3-3.3) for DSA, and 2.9% (CI 2.8-3.0) for PLA. Crude dislocation revision rates were 0.3% (CI 0.1-0.8) for DSA, versus 1.0% (CI 0.9-1.0) for PLA. Dislocation revision rate for DSA did not differ from DAA (0.3% [CI 0.2-0.3]). Multivariable Cox regression analysis demonstrated no overall difference in revision rates for the DSA (HR 0.6 [CI 0.4-1.09) compared with the PLA. Lower risk of revision due to dislocation was found in patients operated on through the DSA (HR 0.3 [0.1-0.9]) compared with the PLA.

CONCLUSION

Early nationwide results suggest that the DSA for total hip arthroplasty seems to show a tendency towards a lower risk of revision for dislocation but no overall reduced revision risk compared with the PLA.

Posterior Approach Total Hip Arthroplasty Utilizing a Monoblock Dual-Mobility Construct Without Posterior Hip Precautions: A Series of 580 Hips with One Dislocation

BACKGROUND

Instability remains a devastating complication following total hip arthroplasty (THA). Here we describe a mini-posterior approach with a monoblock dual-mobility implant without "traditional posterior hip precautions" yielding excellent results.

METHODS

There were 580 consecutive hips in 575 patients who underwent THA utilizing a monoblock dual-mobility implant and a mini-posterior approach. With this technique, the acetabular component positioning does not rely on tradition intra-operative radiographic abduction and anteversion goals, but rather uses patient-specific anatomic landmarks (anterior acetabular rim and, when visible, the transverse acetabular ligament) to set cup position; stability is assessed with a significant, dynamic intra-operative test of range of motion. Patients' mean age was 64 years (range, 21 to 94) and 53.7% were women.

RESULTS

Mean abduction was 48.4° (range, 29° to 68°) and mean anteversion was 24.7° (range, -1 to 51°). Patient Reported Outcomes Measurement Information System scores improved in every measured domain from preoperative to final postoperative visit. There were seven (1.2%) patients who required reoperation, with mean time to reoperation of 1.3 months (range, one to 176 days). Only one patient (0.2%) who had a pre-operative history of spinal cord injury and Charcot arthropathy dislocated.

CONCLUSION

A posterior approach hip surgeon may want to consider using a monoblock dual-mobility construct and avoidance of traditional posterior hip precautions to achieve early hip stability with an extremely low dislocation rate and high patient satisfaction scores.

Hepatitis C Is Associated With Higher Short-Term Complication Rates After Initial Aseptic and Septic Revision Total Hip Arthroplasty: A Matched Cohort Study

BACKGROUND

It is unclear if hepatitis C virus (HCV) negatively impacts outcomes of revision total hip arthroplasty (rTHA). The purpose of this study is to trend recent rTHA utilization in patients who have HCV and compare postoperative complication rates versus a matched cohort.

METHODS

All patients who underwent rTHA were retrospectively identified in a national database. Patients who had HCV (n = 1,746) were matched 1:3 with a matching group (n = 5,238) for age, gender, and several comorbidities. Cochran-Armitage tests were used to analyze trends in the annual proportion of rTHA performed in patients who had HCV from 2010 to 2019. Rates of 90-day medical and prosthesis-related complications within 2 years postoperatively were compared with multivariable logistic regressions.

RESULTS

The annual proportion of rTHA performed in patients who had HCV significantly increased from 2010 to 2019 (P < .001). Patients who had HCV exhibited significantly higher rates of acute kidney injuries (7.6% versus 4.4%; odds ratio [OR] 1.50), transfusions (20.6% versus 14.6%; OR 1.38), and re-revisions for prosthetic joint infection (10.9% versus 6.5%; OR 1.73). In subgroup analyses, rates of re-revision for prosthetic joint infection after initial aseptic rTHA (7.1% versus 3.8%; OR 1.82) and periprosthetic fracture after initial septic rTHA (4.5% versus 1.6%; OR 2.77) were significantly higher in the HCV cohort.

CONCLUSION

Similar to primary THA, patients who have HCV exhibit significantly increased complication rates after rTHA. With growing utilization in recent years, these data suggest that this population will comprise an increasingly larger proportion of rTHA procedures performed in the coming years.

Mixed messages: most spinal pain and osteoarthritis observational research is unclear or misaligned

OBJECTIVES

We assessed authors' language and methods to determine alignment between reported aims, methods, intent, and interpretations in observational studies in spinal pain or osteoarthritis.

STUDY DESIGN AND SETTING

We searched five databases for observational studies that included people with spinal pain or osteoarthritis published in the last 5 years. We randomized 100 eligible studies, and classified study intent (aims and methods) and interpretations as causal, non-causal, unclear, or misaligned.

RESULTS

Overall, 38% of studies were aligned regarding their intent and interpretation (either causally (22%) or non-causally (16%)). 29% of studies' aims and 29% of study methods were unclear. Intent was misaligned in 16% of studies (where aim differed to method) and 23% of studies had misaligned interpretations (where there were multiple conflicting claims). The most common kind of aim was non-causal (38%), and the most common type of method (39%), intent (38%), and interpretations (35%) was causal.

CONCLUSIONS

Misalignment and mixed messages are common in observational research of spinal pain and osteoarthritis. More than 6 in 10 observational studies may be uninterpretable, because study intent and interpretations do not align. While causal methods and intent are most common in observational research, authors commonly shroud causal intent in non-causal terminology.

[Strategies for stem revision : Surgery planning, implant removal and reimplantation]

BACKGROUND AND PLANNING

Femoral revision represents a challenging procedure in its surgical planning and technical execution. The results are mainly dependent on the bone loss present, the quality of the implant removal and the choice of revision system. Patient-specific factors such as age, comorbidities, bone quality or even the localization of the cement have a decisive influence on the surgical strategy. Appropriate preoperative preparation, including the presence of the necessary special instruments, which are essential for gentle implant removal, is indispensable to achieve the best possible result.

THERAPY

A bone-sparing implant removal can be particularly challenging, especially in the case of well-fixed stems and cement residues, which may extend far beyond the isthmus. In such situations, a transfemoral approach should be considered. Cementless reimplantation using modular or non-modular titanium stems is currently the preferred treatment of choice for most revisions. In elderly, low-demand patients or with poor bone quality, cemented revision remains a good alternative treatment option.

Temporal Trends in Deep Surgical Site Infections After Six Orthopaedic Procedures Over a 12-year Period Within a US-based Healthcare System

INTRODUCTION

Centers of excellence and bundled payment models have driven perioperative optimization and surgical site infection (SSI) prevention with decolonization protocols and antibiotic prophylaxis strategies. We sought to evaluate time trends in the incidence of deep SSI and its causative organisms after six orthopaedic procedures in a US-based integrated healthcare system.

METHODS

We conducted a population-level time-trend study using data from Kaiser Permanente's orthopaedic registries. All patients who underwent primary anterior cruciate ligament reconstruction (ACLR), total knee arthroplasty (TKA), elective total hip arthroplasty (THA), hip fracture repair, shoulder arthroplasty, and spine surgery were identified (2009 to 2020). The annual incidence of 90-day deep SSI was identified according to the National Healthcare Safety Network/Centers for Disease Control and Prevention guidelines with manual chart validation for identified infections. Poisson regression was used to evaluate annual trends in SSI incidence with surgical year as the exposure of interest. Annual trends in overall incidence and organism-specific incidence were considered.

RESULTS

The final study sample was composed of 465,797 primary orthopaedic procedures. Over the 12-year study period, a decreasing trend in deep SSI was observed for ACLR and hip fracture repair. Although there was variation in incidence rates for specific operative years for TKA, elective THA, shoulder arthroplasty, and spine surgery, no consistent decreasing trends over time were found. Decreasing rates of Staphylococcus aureus infections over time after hip fracture repair, shoulder arthroplasty, and spine surgery and decreasing trends in antibiotic resistance after elective THA and spine surgery were also observed. Increasing trends of polymicrobial infections were observed after TKA and Cutibacterium acnes after elective THA.

CONCLUSIONS

The overall incidence of deep SSI after six orthopaedic procedures was rare. Decreasing SSI rates were observed for ACLR and hip fracture repair within our US-based healthcare system. Polymicrobial infections after TKA and Cutibacterium acnes after elective THA warrant closer surveillance.

LEVEL OF EVIDENCE

IV.

Anterior hip replacement: lower dislocation rates despite less restrictions?

INTRODUCTION

Dislocation in Total hip arthroplasty (THA) is a common postoperative complication and reason for revision surgery. The direct anterior approach has become more popular over the last decade. The purpose of this study was to compare postoperative dislocation rates of the direct anterior and the posterior approach at a one-year follow-up.

MATERIAL AND METHODS

797 consecutive hips operated through a posterior approach [698 patients (307 male, 391 female)] between 2009 and 2012, were compared to 690 selected THA [610 patients (423 female, 187 male)] operated since 2012. Anterior hip replacement surgery was primarily indicated for patients demanding increased flexibility after surgery (Yoga) or were considered a higher risk for dislocation.

RESULTS

During a one-year follow-up there were eight dislocations out of 797 THA (1%) in the posterior group and none in the 690 THA (0%) in the anterior group (p-value of 0.008). Average time to dislocation was 7.5 weeks in the posterior group. Five of eight patients with dislocations needed revision surgery due to persistent instability.

CONCLUSION

Even in a higher-risk patient population, the direct anterior approach showed a lower dislocation rate compared to the posterior approach in the first year after surgery.

Periprosthetic joint infection rates across primary total hip arthroplasty surgical approaches: a systematic review and meta-analysis of 653,633 procedures

INTRODUCTION

Evidence demonstrates comparable clinical outcomes across the various surgical approaches to primary total hip arthroplasty (THA). However, high-quality contemporary data regarding periprosthetic joint infection (PJI) risk between direct anterior approach (DAA) and other (THA) approaches is lacking. This systematic review and meta-analysis evaluated PJI rates reported in the literature between the DAA and other approaches.

MATERIALS AND METHODS

Five online databases were queried for all studies published from January 1st, 2000 through February 17th, 2021 that reported PJI rates between DAA and other surgical approaches. Studies reporting on primary THAs for osteoarthritis (OA) and that included PJI rates segregated by surgical approach were included. Articles reporting on revision THA, alternative THA etiologies, or minimally invasive techniques were excluded. Mantel-Haenszel (M-H) models were utilized to evaluate the pooled effect of surgical approach on infection rates. Validated risk of bias and methodological quality assessment tools were applied to each study. Multiple sensitivity analyses were conducted to evaluate the robustness of analyses.

RESULTS

28 articles reporting on 653,633 primary THAs were included. No differences were found between DAA cohorts and combined other approaches (OR: 0.95; 95% CI 0.74-1.21; p = 0.67) as well as segregated anterolateral approach cohorts (OR: 0.82, 95% CI 0.64-1.06; p = 0.13). However, DAA patients had a significantly reduced risk of infection compared to those undergoing posterior (OR: 0.66, 95% CI 0.58-0.74; p < 0.0001) and direct lateral (OR: 0.56, 95% CI 0.48-0.65; p < 0.00001) approaches.

CONCLUSION

The DAA to primary THA had comparable or lower PJI risk when compared to other contemporary approaches. The results of the most up-to-date evidence available serve to encourage adult reconstruction surgeons who have already adopted the DAA. Additionally, orthopaedic surgeons considering adoption or use of the direct anterior approach for other reasons should not be dissuaded over theoretical concern for a general increase in the risk of PJI.

LEVEL OF EVIDENCE

Level III.

Comparison of Postoperative Instability and Acetabular Cup Positioning in Robotic-Assisted Versus Traditional Total Hip Arthroplasty

BACKGROUND

Robotic-assisted total hip arthroplasty (R-THA) affords precision yet uncertain clinical benefits. This study compares dislocation rates and related revisions between R-THA and manual total hip arthroplasty (M-THA). Secondarily we evaluated cup position, patient-reported outcome measures (PROMs), and postoperative complications.

METHODS

A three-surgeon cohort study was conducted on 2247 consecutive patients (1724 M-THA and 523 R-THA) who received a primary THA between January 2014 and June 2020 at a single hospital. Demographics, PROMs, emergency department visits, readmissions, and 90-day complications were collected via the Michigan Arthroplasty Registry Collaborative Quality Initiative. Chart review yielded instability occurrence with an average follow-up of 4 years. Multivariate regression analysis was performed, and a sample of 368 radiographs, including all dislocations, were assessed.

RESULTS

There were significantly lower rates of dislocation in R-THA (0.6%) vs M-THA (2.5%; Multivariate odds ratio 3.74, P < .046). All cases of unstable R-THA were successfully treated conservatively, whereas 46% of unstable M-THA were revised for recurrent instability. Cup anteversion (25.6° ± 5.4° R-THA vs 20.6° ± 7.6° M-THA) was greater, and cup inclination (42.5° ± 5.3° R-THA vs 47.0° ± 6.7° M-THA) was lower in the R-THA group (P < .05). No significant differences were noted for demographics, PROMs, or other complications (P > .05).

CONCLUSION

R-THA resulted in less than one-fourth the dislocation rate compared to M-THA and no revision for instability. It was associated with no difference in PROMs or other early complications. The influence of R-THA on stability goes beyond simply cup positioning and deserves further study.

Is the Direct Anterior Approach to THA Cost-effective? A Markov Analysis

BACKGROUND

The use of the direct anterior approach, a muscle-sparing technique for THA, has increased over the years; however, this approach is associated with longer procedure times and a more expensive direct cost. Furthermore, studies have shown a higher revision rate in the early stages of the learning curve. Whether the clinical advantages of the direct anterior compared with the posterior approach-such as less soft tissue damage, decreased short-term postoperative pain, a lower dislocation rate, decreased length of stay in the hospital, and higher likelihood of being discharged home-outweigh the higher cost is still debatable. Determining the cost-effectiveness of the approach may inform its utility and justify its use at various stages of the learning curve.

QUESTIONS/PURPOSES

We used a Markov modeling approach to ask: (1) Is the direct anterior approach more likely to be a cost-effective approach than the posterior approach over the long-term for more experienced or higher volume hip surgeons? (2) How many procedures does a surgeon need to perform for the direct anterior approach to be a cost-effective choice?

METHODS

A Markov model was created with three health states (well-functioning THA, revision THA, and death) to compare the cost-effectiveness of the direct anterior approach with that of the posterior approach in five scenarios: surgeons who performed one to 15, 16 to 30, 31 to 50, 51 to 100, and more than 100 direct anterior THAs during a 6-year span. Procedure costs (not charges), dislocation costs, and fracture costs were derived from published reports, and model was run using two different cost differentials between the direct anterior and posterior approaches (USD 219 and USD 1800, respectively). The lower cost was calculated as the total cost differential minus pharmaceutical and implant costs to account for differences in implant use and physician preference regarding postoperative pain management. The USD 1800 cost differential incorporated pharmaceutical and implant costs. Probabilities were derived from systematic review of the evidence as well as from the Australian Orthopaedic Association National Joint Replacement Registry. Utilities were estimated from best available literature and disutilities associated with dislocation and fracture were incorporated into the model. Quality of life was expressed in quality-adjusted life years (QALYs), which are calculated by multiplying the utility of a health state (ranging from 0 to 1) by the duration of time in that health state. The primary outcome measure was the incremental cost-effectiveness ratio, or the change in costs divided by the change in QALYs when the direct anterior approach was used for THA. USD 100,000 per quality-adjusted life years was used as a threshold for willingness to pay. One-way and probabilistic sensitivity analyses were performed for the scenario in which the direct anterior approach is cost-effective to further account for uncertainty in model inputs.

RESULTS

At a cost differential of USD 219 (95% CI 175 to 263), the direct anterior approach was associated with lower cost and higher effectiveness compared with the posterior approach for surgeons with an experience level of more than 100 operations during a 6-year span. At a cost differential of USD 1800 (95% CI 1440 to 2160), the direct anterior approach remained a cost-effective strategy for surgeons who performed more than 100 operations. At both cost differentials, the direct anterior approach was not cost-effective for surgeons who performed fewer than 100 operations. One-way sensitivity analyses revealed the model to be the most sensitive to fluctuations in the utility of revision THA, probability of revision after the posterior approach THA, probability of dislocation after the posterior approach THA, fluctuations in the probability of dislocation after direct anterior THA, cost of direct anterior THA, and probability of intraoperative fracture with the direct anterior approach. At the cost differential of USD 219 and for surgeons with a surgical experience level of more than 100 direct anterior operations, the direct anterior approach was still the cost-effective strategy for the entire range of values.

CONCLUSION

For high-volume hip surgeons, defined here as surgeons who perform more than 100 procedures during a 6-year span, the direct anterior approach may be a cost-effective strategy within the limitations imposed by our analysis. For lower volume hip surgeons, performing a more familiar approach appears to be more cost-effective.

Current Trends in Revision Hip Arthroplasty: Indications and Types of Components Revised

BACKGROUND

The materials and techniques for both primary and revision total hip arthroplasty (THA) have changed over time. This study evaluated if the indications for revision THA, rates of components utilized (femoral or acetabulum, both, or head/liner exchange), length of stay (LOS), and payments to surgeons and facilities have also changed.

METHODS

A retrospective study, utilizing the PearlDiver database, of 38,377 revision THA patients from January 2010 through December 2018 was performed. Data included the indication for revision, components revised (femoral or acetabulum, both, or head/liner exchange), LOS, and payments. Indications and components were analyzed by logistic regression (Dunnett's post hoc test). Revision totals were analyzed with a linear regression model. Analysis of variance assessed changes in LOS and payments.

RESULTS

Patients' median age was 67 years (Q1-Q3: 59-74), and 58.7% were female. Revisions for dislocation decreased between 2010 and 2018 (odds ratio [OR] 0.82, 95% confidence interval [CI] 0.68-0.98). Revisions for component loosening increased (OR 1.54, 95% CI 1.25-1.91). Dislocation remained the most common indication (19.3%), followed by PJI (17.3%) and loosening (17.1%). Both-component (OR:1.45; 95% CI:1.25-1.67) and femoral component only revisions increased; acetabular component only and head/liner exchanges decreased. Acetabular (OR 0.57, 95% CI 0.47-0.70) and head/liner exchange (OR 0.29, 95% CI 0.20-0.43) revisions decreased, while both component exchange (OR 1.45, 95% CI 1.25-1.67) and femoral revisions (OR 1.17, 95% CI 0.99-1.37) increased. Average LOS (-0.68 days; P < .001) and surgeon payments decreased (-$261.8; P < .001) while facility payments increased ($4,211; P < .001).

CONCLUSION

Indications for revision THA in this database study changed over time, with revision for dislocation decreasing and revision for loosening increasing over time. Both component and femoral revisions increased, and acetabular component and head/liner exchanges decreased. It is possible that these associations could be attributed to a number of details, the method of femoral fixation, surgical approach, and cementing, all of which require additional study.

Acetabular defect management and revision arthroplasty via the direct anterior approach

OBJECTIVE

Acetabular revision arthroplasty and osseous defect management through the direct anterior approach (DAA) with or without proximal extension.

INDICATIONS

Aseptic or septic component loosening, periacetabular osseous defects, pelvic discontinuity, intrapelvic cup protrusion, anterior pseudotumors, iliopsoas tendonitis, polyethylene wear or iliopsoas abscess.

CONTRAINDICATIONS

Clinically relevant gluteal tendon lesions, active infection, morbid obesity, large abdominal pannus, ASA (American Society of Anesthesiologists) score > III, inguinal skin infection.

SURGICAL TECHNIQUE

Electrocautery dissection is recommended to dissect the Hueter interval and to debulk pericapsular scar tissue. At all times during capsular debulking, it should be made sure not to damage the iliopsoas tendon or the neurovascular bundle. A stepwise releasing sequence can facilitate dislocation of the prosthesis. Most cases can be revised via the standard DAA but certain circumstances require an intra- or extrapelvic extension. Access to the anterior gluteal surface of the ilium can be provided using a "tensor snip". More posterior access is provided by the extensile extrapelvic approach described by Smith-Petersen. The intrapelvic Levine extension offers access to the entire visceral surface of the ilium and large parts of the anterior column.

POSTOPERATIVE MANAGEMENT

Patient revised via the intra- or extrapelvic extension and patients suffering from extensive soft tissue or osseous defects should undergo postoperative weight-bearing restrictions with 20 kg for 6 weeks.

RESULTS

Based on our studies, there is no limitation on the type of acetabular implant that can be used in DAA revision arthroplasty. Moreover, virtually all types of periacetabular osseous defects can be managed through the approach and its extensions. Acetabular revision arthroplasty via the DAA and its extensions is safe and can result in good midterm results.

Effect of Sickle Cell Trait on Total Hip Arthroplasty in a Matched Cohort

BACKGROUND

It is unclear if sickle cell trait (SCT) carrier status conveys an increased risk for poor outcomes following total hip arthroplasty (THA). The purpose of this study is to compare short-term clinical outcomes of THA for patients with SCT vs matched controls.

METHODS

Patient records were queried from the PearlDiver database using International Classification of Diseases, Ninth and Tenth Revision and Current Procedural Terminology codes. Patients with SCT who underwent THA were matched 1:1 with controls across age, gender, Elixhauser Comorbidity Index, obesity, and US region. Thirty-day and 90-day rates of systemic complications and 1-year and 2-year rates of joint complications were compared with logistic regression.

RESULTS

In total, 1646 patients were assigned to each cohort. In the 30-day and 90-day postoperative periods, SCT carriers had a higher likelihood of cerebrovascular accident, anemia, acute renal failure, pneumonia, sepsis, deep vein thrombosis, pulmonary embolism, and respiratory failure (all P < .05). SCT carriers exhibited significantly higher risk of periprosthetic joint infection at both 1 (3.5% vs 2.1%; odds ratio [OR] 1.91, 95% confidence interval [CI] 1.22-2.99) and 2 years (3.7% vs 2.6%; OR 1.63, 95% CI 1.07-2.49) postoperatively. Prosthetic loosening was also significantly more likely for SCT carriers within 1 year (1.3% vs 0.3%; OR 4.49, 95% CI 1.75-13.86).

CONCLUSION

Patients with SCT exhibited significantly higher risk for systemic complications, periprosthetic joint infection, and prosthetic loosening after THA. Increased perioperative efforts should be made to prevent hypoxia, acidosis, and dehydration, as these states increase red blood cell sickling, which may reduce complication rates and improve outcomes in patients with SCT.

Anterior approach to hip replacement and associated complications: an independent review

BACKGROUND

Direct anterior approach (DAA) to hip replacement is increasingly popular. Despite the well-published benefits of early recovery, the approach can be associated with a number of complications that may be underreported. We aim to report the incidence of some of these complications in a large retrospective case series.

METHODS

270 consecutive DAA hip replacements are studied which are performed by a single high-volume hip surgeon from 2013 to 2015, not including the surgeon's learning curve. Operation and consultation records were screened, and focused questioning via telephone was employed to capture specific complications including dislocations, wound infections, lateral femoral cutaneous nerve (LFCN) injury and revision surgery.

RESULTS

240 of 270 patients or family were contactable. The mean age and body mass index of the cohort was 66 (range 30-89) years and 27 (range 18-40) kg/m2 respectively. The mean follow-up was 3.7 years. Wound issues were encountered in 24 patients (8.8%). There were 9 dislocations (3%). 27 (10%) patients needed revision surgery in the follow-up period. Reasons for revision included leg-length discrepancies, dislocations, ongoing pain and aseptic loosening. 9 (3.4%) patients had to return to operating theatre for reasons other than revision surgery. Symptoms of lateral femoral cutaneous nerve injury was reported by 54 patients (21%).

CONCLUSIONS

While the short-term benefits of DAA have been widely reported, our review shows a relatively high rate of revision surgery. We feel that the enthusiasm for DAA should be tempered until further evidence is available.

Does Surgical Approach Influence the Natural History of the Unstable Total Hip Arthroplasty?

BACKGROUND

Dislocation following total hip arthroplasty (THA) is a significant complication that occurs in 0.3%-10% of cases with 13%-42% of patients requiring revision surgery. The literature has primarily focused on the dislocation risk associated with different surgical approaches. However, little is known about the natural history of the dislocated hip and whether surgical approach of the index THA is associated with further instability and revision surgery.

METHODS

This is a retrospective, single-center, multi-surgeon consecutive case series of all patients who experienced THA dislocation from 2002 to 2020. Patients were excluded if the initial dislocation was secondary to infection or fracture. The natural history of the cohort as per approach was determined. Outcome measurements of interest were the number of dislocations; the treatment surrounding each dislocation; the necessity and type of revision; and the complications encountered.

RESULTS

Of the 75 patients, 58 (77%) dislocated within 6 months following primary THA. The anterior group had greater odds of dislocation within 2 weeks post-THA compared to the lateral and posterior groups (P = .04). The mean number of dislocations per patient was significantly lower in the anterior (1.5 ± 0.7) compared to the lateral (2.4 ± 1.2) and posterior (2.1 ± 1.0) groups (P = .02). Revision surgery was needed in 30% (6/20) of patients in the anterior, 69% (25/36) of the posterior, and 68% (13/19) of the lateral groups (P = .01).

CONCLUSION

This study illustrates that while primary THA dislocations happen earlier with the anterior approach, they are typically less complicated and have a lower risk of recurrent instability and revision surgery.

Direct Anterior Approach for Primary Total Hip Arthroplasty Lowers the Risk of Dislocation Compared to the Posterior Approach: A Single Institution Experience

BACKGROUND

One purported benefit of the direct anterior approach (DAA) for total hip arthroplasty (THA) is a lower rate of postoperative dislocation.

METHODS

An institutional database was used to identify 8840 primary THAs performed from 2003 to 2020 including 5065 (57%) performed using the DAA and 3775 (43%) performed via the posterior approach (PA). Direction and mechanism of dislocation were determined from chart review. Outcomes were compared using Kaplan-Meier survivorship with dislocation as the endpoint and a Cox multivariate regression was used to investigate factors associated with dislocation. The mean follow-up was 1.7 ± 2.0 years for the DAA and 3.1 ± 3.3 years for the PA.

RESULTS

The 0.5% (26/5065) incidence of dislocation among DAA hips was significantly less than the 3.3% (126/3775) among PA cases (P < .001). The majority of dislocations were posterior (DAA 57%, PA 79%) and occurred during activities of daily living (DAA 82%, PA 77%). Five-year survivorship was significantly higher for the DAA group compared to the PA group (99.1% vs 95.4%, P < .001). Dislocation risk was 4.9 times higher for the PA compared to the DAA (hazard ratio = 4.9, 95% confidence interval = 3.2-7.5, P < .001). Increasing head diameter reduced the risk (hazard ratio = 0.70, 95% confidence interval = 0.57-0.86, P < .001). The 0.2% incidence (10/5065) of revision for instability among the DAA group was significantly lower than the 1.1% (43/3775) rate for the PA group (P < .001).

CONCLUSION

Compared to primary THAs performed with the PA, DAA cases had a lower risk of dislocation, higher survivorship with dislocation as an endpoint, and a lower risk of revision for instability in this single institution cohort.

Early failure of an uncemented femoral stem, as compared to two other stems with similar design, following primary total hip arthroplasty performed with direct anterior approach

INTRODUCTION

An increased risk of early femoral component loosening has been reported using the direct anterior approach (DAA) compared with other common surgical approaches. However, long-term data are scarce. The purpose of this study is: (1) to determine the incidence of early femoral loosening in a high volume, single surgeon's practice utilising the DAA approach; and (2) to examine the effect of stem design and type of coating on aseptic loosening in the early and mid-term postoperative period.

METHODS

A retrospective review of 1650 consecutive patients (1800 hips) who underwent total hip arthroplasty (THA) using the DAA between August 2011 and December 2017 was conducted at our institution. 3 types of uncemented femoral stems (Quadra-S, Avenir, TwinSys), with similar design, but different coating, were implanted. Patients were evaluated clinically and radiologically at 4 weeks, 3 months, 1 year, and annually thereafter.

RESULTS

After a mean follow-up of 46.4 months, the total incidence of revision for aseptic loosening was 0.44% (n = 8). All loose stems were Quadra-S, failing to achieve osseointegration, for an overall incidence of 0.96% (p = 0.002). None of the other stems were loose. Radiolucent lines around the proximal stem portion were visible in 75 Quadra-S stems (4.1%) on radiographs taken at 1 year postoperatively and continued to deteriorate at the latest follow-up.

CONCLUSIONS

In this specific cohort of patients, the increased rate of femoral stem aseptic loosening was implant-related and was attributed only to a specific type of femoral stem (Quadra-S). No relation to other factors was proven suggesting that the surface characteristics of this femoral stem and the lack of bioactive coating are responsible for the observed early femoral failures. These findings should be confirmed by additional registry work and larger population sample sizes are needed to evaluate the prosthesis performance after implantation through the DAA.

Revision Risk in a Cohort of US Patients Younger Than 55 Undergoing Primary Elective Total Hip Arthroplasty

BACKGROUND

As indications for elective total hip arthroplasty (THA) expand to younger patients, we sought to (1) compare revision risk following primary elective THA in patients <55 years at the time of their THA to patients aged ≥65 years and (2) identify specific risk factors for revision in patients <55 years.

METHODS

A Kaiser Permanente's total joint replacement registry was used to conduct a cohort study including primary elective THA patients aged ≥18 (2001-2018). In total, 11,671 patients <55 years and 53,106 patients ≥65 years were included. Multiple Cox regression was used to evaluate cause-specific revision risk, including septic revision, aseptic loosening, instability, and periprosthetic fracture. Stepwise Cox regression was used to identify patient and surgical factors associated with cause-specific revision in patients <55 years.

RESULTS

Patients <55 years had a higher risk of septic revision (hazard ratio [HR] = 1.30, 95% confidence interval [CI] = 1.02-1.66), aseptic loosening (HR = 2.60, 95% CI = 1.99-3.40), and instability (HR = 1.35, 95% CI = 1.09-1.68), but a lower risk of revision for periprosthetic fracture (HR = 0.36, 95% CI = 0.22-0.59) compared to patients aged ≥65 years. In the <55 age group, risk factors for septic revision included higher body mass index, drug abuse, and liver disease. Hypertension, anterior approach, and ceramic-on-ceramic were associated with aseptic loosening. White race, American Society of Anesthesiologists classification ≥3, smoker, paralysis, posterior approach, ceramic-on-ceramic, and smaller head diameter were associated with instability.

CONCLUSION

Identified risk factors varied depending on the cause for revision. Although septic revisions were related to patient characteristics, more modifiable factors, such as implant or surgical approach, were associated with revision due to aseptic loosening and instability.

LEVEL OF EVIDENCE

III.

Does Approach Influence the Dislocation Rate Following Head and Liner Exchange in Revision Hip Arthroplasty?

BACKGROUND

Revision total hip arthroplasty with modular component exchange can limit morbidity by retaining well-fixed components but dislocation has been a relatively frequent postoperative complication. This study evaluated the effect of surgical approach on dislocation rate in a modern revision cohort.

METHODS

From 2010 to 2020, 248 aseptic head and liner exchanges were performed at a single institution. The mean patient age at revision was 64.9 ± 10.4 years and 50% (123/248) were performed among males. Indications for revision included 140 (56%) for polyethylene wear, 68 (27%) for failed metal-on-metal components, and 40 (16%) for instability. The mean follow-up after revision was 2.3 years.

RESULTS

Thirty (12%) hips dislocated at a mean of 0.6 years (range 0.01-4.6) postoperatively. The dislocation rate by revision approach was 17% (9/54) for the direct anterior, 6% (5/80) for the direct lateral, and 14% (16/114) for the posterolateral approach (P = .13). Hips revised by the direct anterior approach that dislocated were more abducted (51 ± 8 vs 45 ± 8, P = .05) and more anteverted (26 ± 9 vs 20 ± 7, P = .04) than non-dislocators. Among all 248 hips, cups with more than 48° of abduction were 2.6 times more likely to dislocate (P = .01). Head diameter, neck length, patient age, and gender were not associated with dislocation (P ≥ .20).

CONCLUSION

Dislocation remains a common complication after head and liner exchange regardless of approach. Cup position is associated with postoperative instability and must be critically evaluated during preoperative planning.

The direct anterior approach to the hip: a useful tool in experienced hands or just another approach?

The direct anterior approach (DAA) to the hip was initially described in the nineteenth century and has been used sporadically for total hip arthroplasty (THA). However, recent increased interest in tissue-sparing and small incision arthroplasty has given rise to a sharp increase in the utilization of the DAA. Although some previous studies claimed that this approach results in less muscle damage and pain as well as rapid recovery, a paucity in the literature exists to conclusively support these claims. While the DAA may be comparable to other THA approaches, no evidence to date shows improved long-term outcomes for patients compared to other surgical approaches for THA. However, the advent of new surgical instruments and tables designed specifically for use with the DAA has made the approach more feasible for surgeons. In addition, the capacity to utilize fluoroscopy intraoperatively for component positioning is a valuable asset to the approach and can be of particular benefit for surgeons during their learning curve. An understanding of its limitations and challenges is vital for the safe employment of this technique. This review summarizes the pearls and pitfalls of the DAA for THA in order to improve the understanding of this surgical technique for hip replacement surgeons.

Horror of three synergistic factors in THA: high mechanical stress, dissimilar metals, low elasticity stem: a case report

Background

A large-diameter femoral head is effective in preventing dislocation after total hip arthroplasty. However, although rare, catastrophic stem tribocorrosion may occur at the head-stem junction.

Case presentation

A 70-year-old woman underwent revision surgery 7.5 years after total hip arthroplasty because of catastrophic stem corrosion with dissociation of the metal head (cobalt/chromium) and stem (TiMo12Zr6Fe2). Abnormal levels of cobalt were found in the intra-articular fluid, capsule, hip muscle, and blood. Revision surgery was performed via the direct anterior approach. The well-fixed femoral stem was explanted, and a cemented stainless stem with stainless head was implanted. Three months after the revision surgery, the cobalt concentration in the blood had decreased to normal.

Conclusions

Stem dissociation in the present case might have been caused by synergistic combination of a 36-mm-diameter femoral head and long neck length offset with high frictional torque, a cobalt-chromium head with a high risk of galvanic corrosion, and a TMZF (TiMo12Zr6Fe2) alloy stem with a low Young’s modulus of elasticity. The combination of these factors must be avoided.

How Does Implant Survivorship Vary with Different Corail Femoral Stem Variants? Results of 51,212 Cases with Up to 30 Years Of Follow-up from the Norwegian Arthroplasty Register

BACKGROUND

The Corail® cementless stem (DePuy Synthes) has been used in Norway since 1987 and is one of the most frequently used stems in THA worldwide. Although the published survival results of the standard Corail stem have been good, little is known about the long-term (more than 20 years) survival of other stem design variants. Further, some changes were made to the extramedullary part of the stem in 2003, and the effect of these changes on survival is unknown.

QUESTIONS/PURPOSES

(1) What is the survival up to 30 years of the standard collarless Corail femoral stem, and were extramedullary changes (slimmer, polished and rectangular neck, shorter taper) associated with differences in survivorship? (2) How does the 10-year survival and the risk of revision of other Corail stem variants, including the standard collared stem, coxa vara collared stem, and high offset collarless stem, compare with those of the standard collarless stem? (3) Which factors are associated with an increased risk of revision of the Corail stem, and are there any differences in those factors among the four stem variants?

METHODS

Data for this study were drawn from the Norwegian Arthroplasty Register. Since 1987, THAs have been registered in the Norwegian Arthroplasty Register with completeness of data greater than 97% for primary THAs and 93% for revisions. To study survivorship with up to 30 years of follow-up (1987 to 2018; median 7.7-year follow-up), and to compare the original stem with stems with extramedullary modifications, we included 28,928 standard collarless Corail stems in 24,893 patients (mean age at time of implantation 62 years; 66% [16,525 of 24,893] were women). To compare the newer stem variants with the standard collarless stem (2008 to 2018), we included 20,871 standard collarless, 10,335 standard collared, 6760 coxa vara collared, and 4801 high offset collarless stems. Survival probabilities were estimated using the Kaplan-Meier method with endpoints of stem revision, revision due to aseptic stem loosening, and periprosthetic fracture. The endpoint of all noninfectious causes of THA revision (including cup revision) was additionally analyzed for the long-term comparison. The proportion of patients who died was limited, and there was no difference in death rate between the groups compared. Therefore, we believe that competing events were not likely to influence survivorship estimates to a large degree. To compare different stem variants and evaluate factors that could be associated with the risk of revision, we calculated hazard ratios using Cox regression analyses with adjustments for gender, age group, surgical approach, diagnosis, and stem size.

RESULTS

The 30-year Kaplan-Meier survival of the standard collarless stem was 88.4% (95% confidence interval 85.4% to 91.4%), 93.3% (95% CI 91.1% to 95.5%), and 94.4% (95% CI 92.0% to 96.8%) using stem revision for any noninfectious cause, aseptic loosening, and periprosthetic fracture of the femur as endpoints, respectively. There was no difference in survival between the original stem and the modified stem. The 10-year Kaplan-Meier survivorship free of stem revision (all causes including infection) was 97.6% (95% CI 97.2% to 98.0%) for the standard collarless stem, 99.0% (95% CI 98.8% to 99.2%) for the standard collared stem, 97.3% (95% CI 96.3% to 98.3%) for the coxa vara collared stem, and 95.0% (95% CI 93.6% to 96.4%) for the high offset collarless stem. Compared with the standard collarless stem, the standard collared stem performed better (HR 0.4 [95% CI 0.3 to 0.6]; p < 0.001) and the high offset collarless stem performed more poorly (HR 1.4 [95% CI 1.1 to 1.7]; p = 0.006) with any stem revision as the endpoint, and similar results were found with revision for aseptic stem loosening and periprosthetic fracture as endpoints. Controlling for the noted confounders, the standard collared stem had a lower revision risk. The high offset collarless stem had an increased stem revision risk for any reason (HR 1.4 [95% CI 1.1 to 1.7]; p = 0.006) and aseptic loosening (HR 1.6 [95% CI 1.1 to 2.3]; p = 0.022). Other factors associated with an increased risk of stem revision for all stem variants were being a man (HR 1.7 [95% CI 1.4 to 2.0]; p < 0.001), age 70 to 79 years and 80 years and older compared with the age group of 50 to 59 years (HR 1.6 [95% CI 1.2 to 2.0]; p < 0.001 and HR 1.9 [95% CI 1.4 to 2.6]; p < 0.001, respectively), the anterior approaches (direct anterior Smith-Petersen and anterolateral Watson-Jones combined) compared with the posterior approach (HR 1.4 [95% CI 1.1 to 1.7]; p = 0.005), as well as a preoperative nonosteoarthritis diagnosis (HR 1.3 [95% CI 1.0 to 1.6]; p = 0.02) and small stem sizes (sizes 8-11) compared with the medium sizes (sizes 12-15) (HR 1.4 [95% CI 1.1 to 1.6]; p = 0.001). The very small sizes (8 and 9) were associated with a 2.0 times higher risk of revision (95%. CI 1.4 to 2.6; p < 0.01) compared with all other sizes combined.

CONCLUSION

When using the uncemented Corail stem, surgeons can expect good results with up to 30 years of follow-up. Our results should be generalizable to the typical surgeon at the average hospital in a comparable setting. From our results, using a collared variant would be preferable to a collarless one. Due to an increased risk of periprosthetic fracture, caution with the use of the uncemented Corail stem in patients older than 70 years, especially in women, is warranted. Poorer stem survival should also be expected with the use of small stem sizes. The risk of periprosthetic fractures for the Corail uncemented stem versus cemented stems in different age categories has not been extensively examined, nor has the use of a collar for different age groups and genders, and both should be subjects for further investigation.

LEVEL OF EVIDENCE

Level III, therapeutic study.