Hip replacement Ferguson, Rory J; Palmer, Antony JR; Taylor, Adrian ...
The Lancet (British edition),
11/2018, Letnik:
392, Številka:
10158
Journal Article
Recenzirano
Total hip replacement is a frequently done and highly successful surgical intervention. The procedure is undertaken to relieve pain and improve function in individuals with advanced arthritis of the ...hip joint. Symptomatic osteoarthritis is the most common indication for surgery. In paper 1 of this Series, we focus on how patient factors should inform the surgical decision-making process. Substantial demands are placed upon modern implants, because patients expect to remain active for longer. We discuss the advances made in implant performance and the developments in perioperative practice that have reduced complications. Assessment of surgery outcomes should include patient-reported outcome measures and implant survival rates that are based on data from joint replacement registries. The high-profile failure of some widely used metal-on-metal prostheses has shown the shortcomings of the existing regulatory framework. We consider how proposed changes to the regulatory framework could influence safety.
Metal-on-metal hip replacement (MoMHR) revision surgery for adverse reactions to metal debris (ARMD) has been associated with an increased risk of early complications and reoperation and inferior ...patient-reported outcome scores compared with non-ARMD revisions. As a result, early revision specifically for ARMD with adoption of a lower surgical threshold has been widely recommended with the goal of improving the subsequent prognosis after ARMD revisions. However, no large cohorts have compared the risk of complications and reoperation after MoMHR revision surgery for ARMD (an unanticipated revision indication) with those after non-ARMD revisions (which represent conventional modes of arthroplasty revision).
(1) Does the risk of intraoperative complications differ between MoMHRs revised for ARMD compared with non-ARMD indications? (2) Do mortality rates differ after MoMHRs revised for ARMD compared with non-ARMD indications? (3) Do rerevision rates differ after MoMHRs revised for ARMD compared with non-ARMD indications? (4) How do implant survival rates differ after MoMHR revision when performed for specific non-ARMD indications compared with ARMD?
This retrospective observational study involved all patients undergoing MoMHR from the National Joint Registry (NJR) for England and Wales subsequently revised for any indication between 2008 and 2014. The NJR achieves high levels of patient consent (93%) and linked procedures (ability to link serial procedures performed on the same patient and hip; 95%). Furthermore, recent validation studies have demonstrated that when revision procedures have been captured within the NJR, the data completion and accuracy were excellent. Revisions for ARMD and non-ARMD indications were matched one to one for multiple potential confounding factors using propensity scores. The propensity score summarizes the many patient and surgical factors that were used in the matching process (including sex, age, type of primary arthroplasty, time to revision surgery, and details about the revision procedure performed such as the approach, specific components revised, femoral head size, bearing surface, and use of bone graft) using one single score for each revised hip. The patient and surgical factors within the ARMD and non-ARMD groups subsequently became much more balanced once the groups had been matched based on the propensity scores. The matched cohort included 2576 MoMHR revisions with each study group including 1288 revisions (mean followup of 3 years for both groups; range, 1-7 years). Intraoperative complications, mortality, and rerevision surgery were compared between matched groups using univariable regression analyses. Implant survival rates in the non-ARMD group were calculated for each specific revision indication with each individual non-ARMD indication subsequently compared with the implant survival rate in the ARMD group using Cox regression analyses.
There was no difference between the ARMD and non-ARMD MoMHR revisions in terms of intraoperative complications (odds ratio, 0.97; 95% confidence interval CI, 0.59-1.59; p = 0.900). Mortality rates were lower after ARMD revision compared with non-ARMD revision (hazard ratio HR, 0.43; CI, 0.21-0.87; p = 0.019); however, there was no difference when revisions performed for infection were excluded from the non-ARMD indication group (HR, 0.69; CI, 0.35-1.37; p = 0.287). Rerevision rates were lower after ARMD revision compared with non-ARMD revision (HR, 0.52; CI, 0.36-0.75; p < 0.001); this difference persisted even after removing revisions performed for infection (HR, 0.59; CI, 0.40-0.89; p = 0.011). Revisions for infection (5-year survivorship = 81%; CI, 55%-93%; p = 0.003) and dislocation/subluxation (5-year survivorship = 82%; CI, 69%-90%; p < 0.001) had the lowest implant survival rates when compared with revisions for ARMD (5-year survivorship = 94%; CI, 92%-96%).
Contrary to previous observations, MoMHRs revised for ARMD have approximately half the risk of rerevision compared with non-ARMD revisions. We suspect worldwide regulatory authorities have positively influenced rerevision rates after ARMD revision by recommending that surgeons exercise a lower revision threshold and that such revisions are now being performed at an earlier stage. The high risk of rerevision after MoMHR revision for infection and dislocation is concerning. Infected MoMHR revisions were responsible for the increased mortality risk observed after non-ARMD revision, which parallels findings in non-MoMHR revisions for infection.
Level III, therapeutic study.
Performing THA in patients with high-riding developmental dysplasia of the hip (DDH) is associated with serious complications and technical challenges. Various methods of shortening osteotomy are ...available to facilitate femoral head reduction during THA in patients with high-riding hips; subtrochanteric shortening osteotomy and trochanteric slide osteotomy plus proximal shortening are the most common techniques. However, which approach is superior remains a topic of controversy.
(1) Is there any difference in clinical outcomes (defined as the Harris Hip Score HHS and residual limb length discrepancy) at a minimum of 3 years between subtrochanteric shortening osteotomy and trochanteric slide osteotomy in patients with Crowe Type IV DDH who underwent THA? (2) Is there any difference in the risk or type of complications between the two approaches?
We performed a retrospective, comparative study of two groups (subtrochanteric shortening osteotomy versus trochanteric slide osteotomy) matched for sex and preoperative HHS at a minimum of 3 years of follow-up. Between 2010 and 2018, we performed 67 THAs in patients with unilateral Crowe Type IV DDH. During that time, we generally used a trochanteric slide osteotomy for THA in all patients with Crowe Type IV hips and performed subtrochanteric shortening osteotomy when a conical stem was not available. A total of 42% (28) had THA with subtrochanteric shortening osteotomy, and 58% (39) had THA with trochanteric slide osteotomy. Of those, 89% (25) and 74% (29), respectively, were accounted for with complete datasets for possible matching at a minimum of 3 years of follow-up. Patients were matched for gender and preoperative HSS (within 10 points), leaving 22 patients in each group (79% of the subtrochanteric shortening osteotomy group and 56% of the trochanteric slide osteotomy group) for evaluation and analysis. Age (42 versus 46 years), gender (female: 73% versus 73%), preoperative HSS (40 versus 40), and preoperative leg length discrepancy (5.9 versus 5.3 cm) were comparable between the two groups (p > 0.05). The trochanteric slide osteotomy group exclusively received Cone Wagner (Zimmer) implants (100%), while Corail (DePuy Synthes) implants (77%) were the most commonly used in the subtrochanteric shortening osteotomy group. HHS at a minimum of 3 years as well as the presence or absence of a limp and Trendelenburg sign, functional leg length discrepancy, nonunion, nerve palsy, and other surgical complications were recorded and compared between the groups based on data drawn from a longitudinally maintained institutional database.
At a mean follow-up of 73 months, improvement in HHS was greater in the subtrochanteric shortening osteotomy group than in the trochanteric slide osteotomy group (48 ± 4 points versus 36 ± 11 points, mean difference 12 points 95% CI 7 to 17 points; p < 0.001). Although the preoperative leg length discrepancy was similar between the groups, there was a greater postoperative improvement in the subtrochanteric shortening osteotomy group (44 ± 8 mm and 38 ± 8 mm in the subtrochanteric shortening osteotomy and trochanteric slide osteotomy groups, respectively; p = 0.02). The risk of nonunion was higher with a trochanteric slide osteotomy than with a subtrochanteric shortening osteotomy (23% 5 of 22 versus 0% 0 of 22; p = 0.048). Other complications, including intraoperative periprosthetic fractures, nerve palsy, heterotopic ossification, revision surgery, and dislocation, did not differ between the groups.
In patients with Crowe Type IV hips undergoing THA, surgeons might consider subtrochanteric shortening osteotomy rather than trochanteric slide osteotomy to minimize the risk of nonunion and achieve superior hip function. Better correction of leg length discrepancy may also be possible with subtrochanteric shortening osteotomy. The long-term survivorship of hips after these two techniques, as well as the influence of the specific anatomy of the proximal femur on the choice of technique, remain to be explored in future studies.
Level III, therapeutic study.
The direct lateral approach to THA provides good exposure and is associated with a low risk of dislocations, but can result in damage to the abductor muscles. The direct anterior approach does not ...incise muscle, and so recovery after surgery may be faster, but it has been associated with complications (including fractures and nerve injuries), and it involves a learning curve for surgeons who are unfamiliar with it. Few randomized trials have compared these approaches with respect to objective endpoints as well as validated outcome scores.
The purpose of this study was to compare the direct anterior approach with the direct lateral approach to THA with respect to (1) patient-reported and validated outcomes scores; (2) frequency and persistence of abductor weakness, as demonstrated by the Trendelenburg test; and (3) major complications such as infection, dislocation, reoperation, or neurovascular injury.
We performed a randomized controlled trial recruiting patients from January 2012 to June 2013. One hundred sixty-four patients with end-stage osteoarthritis were included and randomized to either the direct anterior or direct lateral approach. Before surgery and at 3, 6, 12, and 24 months, a physiotherapist recorded the Harris hip score (HHS), 6-minute walk distance (6MWD), and performed the Trendelenburg test directly after the 6MWD. The patients completed the Oxford Hip Score (OHS) and the EQ-5D. The groups were not different at baseline with respect to demographic data and preoperative scores. Both groups received the same pre- and postoperative regimes. Assessors were blinded to the approach used. One hundred fifty-four patients (94%) completed the 2-year followup; five patients from each group were lost to followup.
There were few statistical differences and no clinically important differences in terms of validated or patient-reported outcomes scores (including the HHS, 6MWD, OHS, or EQ-5D) between the direct anterior and the lateral approach at any time point. A higher proportion of patients had a persistently positive Trendelenburg test 24 months after surgery in the lateral approach than the direct anterior approach (16% 12 of 75 versus 1% one of 79; odds ratio, 15; p = 0.001). Irrespective of approach, those with a positive Trendelenburg test had statistically and clinically important worse HHS, OHS, and EQ-5D scores than those with a negative Trendelenburg test. There were four major nerve injuries in the direct anterior group (three transient femoral nerve injuries, resolved by 3 months after surgery, and one tibial nerve injury with symptoms that persist 24 months after surgery) and none in the lateral approach.
Based on our findings, no case for superiority of one approach over the other can be made, except for the reduction in postoperative Trendelenburg test-positive patients using the direct anterior approach compared with when using the direct lateral approach. Irrespective of approach, patients with a positive Trendelenburg test had clinically worse scores than those with a negative test, indicating the importance of ensuring good abductor function when performing THA. The direct anterior approach was associated with nerve injuries that were not seen in the group treated with the lateral approach.
Level I, therapeutic study.
Background
The modified Dunn procedure has the potential to restore the anatomy in hips with slipped capital femoral epiphyses (SCFE) while protecting the blood supply to the femoral head and ...minimizing secondary impingement deformities. However, there is controversy about the risks associated with the procedure and mid- to long-term data on clinical outcomes, reoperations, and complications are sparse.
Questions/Purposes
Among patients treated with a modified Dunn procedure for SCFE, we report on (1) hip pain and function as measured by the Merle d’Aubigné and Postel score, Drehmann sign, anterior impingement test, limp, and ROM; (2) the cumulative survivorship at minimum 10-year followup with endpoints of osteoarthritis (OA) progression (at least one Tönnis grade), subsequent THA, or a Merle d’Aubigné and Postel score < 15; (3) radiographic anatomy of the proximal femur measured by slip angle, α angle, Klein line, and sphericity index; and (4) the risk of subsequent surgery and complications.
Methods
Between 1998 and 2005, all patients who presented to our institution with SCFE were treated with a modified Dunn procedure; this approach was applied regardless of whether the slips were mild or severe, acute or chronic, and all were considered potentially eligible here. Of the 43 patients (43 hips) thus treated during that time, 42 (98%) were available for a minimum 10-year followup (mean, 12 years; range, 10–17 years) and complete radiographic and clinical followup was available on 38 hips (88%). The mean age of the patients was 13 years (range, 9–18 years). Ten hips (23%) presented with a mild, 27 hips (63%) with a moderate, and six hips (14%) with a severe slip angle. Pain and function were measured using the Merle d’Aubigné and Postel score, limp, ROM, and the presence of a positive anterior impingement test or Drehmann sign. Cumulative survivorship was calculated according to the method of Kaplan-Meier with three defined endpoints: (1) progression by at least one grade of OA according to Tönnis; (2) subsequent THA; or (3) a Merle d’Aubigné and Postel score < 15. Radiographic anatomy was assessed with the slip angle, Klein line, α angle, and sphericity index.
Results
The Merle d’Aubigné and Postel score improved at the latest followup from 13 ± 2 (7–14) to 17 ± 1 (14–18; p < 0.001), the prevalence of limp decreased from 47% (18 of 38 hips) to 0% (none in 38 hips; p < 0.001), the prevalence of a positive Drehmann sign decreased from 50% (nine of 18 hips) to 0% (none in 38 hips; p < 0.001), and both flexion and internal rotation improved meaningfully. Cumulative survivorship was 93% at 10 years (95% confidence interval, 85%–100%). Radiographic anatomy improved, but secondary impingement deformities remained in some patients, and secondary surgical procedures included nine hips (21%) with screw removal and six hips (14%) undergoing open procedures for impingement deformities. Complications occurred in four hips (9%) and no hips demonstrated avascular necrosis on plain radiographs.
Conclusions
In this series, the modified Dunn procedure largely corrected slip deformities with little apparent risk of progression to avascular necrosis or THA and high hip scores at 10 years. However, secondary impingement deformities persisted in some hips and of those some underwent further surgical corrections.
Level of Evidence
Level IV, therapeutic study.
Arthroplasties for hip fracture in adults Lewis, Sharon R; Macey, Richard; Parker, Martyn J ...
Cochrane database of systematic reviews,
02/2022, Letnik:
2
Journal Article
Recenzirano
Odprti dostop
Hip fractures are a major healthcare problem, presenting a huge challenge and burden to individuals and healthcare systems. The number of hip fractures globally is rising rapidly. The majority of hip ...fractures are treated surgically. This review evaluates evidence for types of arthroplasty: hemiarthroplasties (HAs), which replace part of the hip joint; and total hip arthroplasties (THAs), which replace all of it.
To determine the effects of different designs, articulations, and fixation techniques of arthroplasties for treating hip fractures in adults.
We searched CENTRAL, MEDLINE, Embase, seven other databases and one trials register in July 2020.
We included randomised controlled trials (RCTs) and quasi-RCTs comparing different arthroplasties for treating fragility intracapsular hip fractures in older adults. We included THAs and HAs inserted with or without cement, and comparisons between different articulations, sizes, and types of prostheses. We excluded studies of people with specific pathologies other than osteoporosis and with hip fractures resulting from high-energy trauma.
We used standard methodological procedures expected by Cochrane. We collected data for seven outcomes: activities of daily living, functional status, health-related quality of life, mobility (all early: within four months of surgery), early mortality and at 12 months after surgery, delirium, and unplanned return to theatre at the end of follow-up.
We included 58 studies (50 RCTs, 8 quasi-RCTs) with 10,654 participants with 10,662 fractures. All studies reported intracapsular fractures, except one study of extracapsular fractures. The mean age of participants in the studies ranged from 63 years to 87 years, and 71% were women. We report here the findings of three comparisons that represent the most substantial body of evidence in the review. Other comparisons were also reported, but with many fewer participants. All studies had unclear risks of bias in at least one domain and were at high risk of detection bias. We downgraded the certainty of many outcomes for imprecision, and for risks of bias where sensitivity analysis indicated that bias sometimes influenced the size or direction of the effect estimate. HA: cemented versus uncemented (17 studies, 3644 participants) There was moderate-certainty evidence of a benefit with cemented HA consistent with clinically small to large differences in health-related quality of life (HRQoL) (standardised mean difference (SMD) 0.20, 95% CI 0.07 to 0.34; 3 studies, 1122 participants), and reduction in the risk of mortality at 12 months (RR 0.86, 95% CI 0.78 to 0.96; 15 studies, 3727 participants). We found moderate-certainty evidence of little or no difference in performance of activities of daily living (ADL) (SMD -0.03, 95% CI -0.21 to 0.16; 4 studies, 1275 participants), and independent mobility (RR 1.04, 95% CI 0.95 to 1.14; 3 studies, 980 participants). We found low-certainty evidence of little or no difference in delirium (RR 1.06, 95% CI 0.55 to 2.06; 2 studies, 800 participants), early mortality (RR 0.95, 95% CI 0.80 to 1.13; 12 studies, 3136 participants) or unplanned return to theatre (RR 0.70, 95% CI 0.45 to 1.10; 6 studies, 2336 participants). For functional status, there was very low-certainty evidence showing no clinically important differences. The risks of most adverse events were similar. However, cemented HAs led to less periprosthetic fractures intraoperatively (RR 0.20, 95% CI 0.08 to 0.46; 7 studies, 1669 participants) and postoperatively (RR 0.29, 95% CI 0.14 to 0.57; 6 studies, 2819 participants), but had a higher risk of pulmonary embolus (RR 3.56, 95% CI 1.26 to 10.11, 6 studies, 2499 participants). Bipolar HA versus unipolar HA (13 studies, 1499 participants) We found low-certainty evidence of little or no difference between bipolar and unipolar HAs in early mortality (RR 0.94, 95% CI 0.54 to 1.64; 4 studies, 573 participants) and 12-month mortality (RR 1.17, 95% CI 0.89 to 1.53; 8 studies, 839 participants). We are unsure of the effect for delirium, HRQoL, and unplanned return to theatre, which all indicated little or no difference between articulation, because the certainty of the evidence was very low. No studies reported on early ADL, functional status and mobility. The overall risk of adverse events was similar. The absolute risk of dislocation was low (approximately 1.6%) and there was no evidence of any difference between treatments. THA versus HA (17 studies, 3232 participants) The difference in the risk of mortality at 12 months was consistent with clinically relevant benefits and harms (RR 1.00, 95% CI 0.83 to 1.22; 11 studies, 2667 participants; moderate-certainty evidence). There was no evidence of a difference in unplanned return to theatre, but this effect estimate includes clinically relevant benefits of THA (RR 0.63, 95% CI 0.37 to 1.07, favours THA; 10 studies, 2594 participants; low-certainty evidence). We found low-certainty evidence of little or no difference between THA and HA in delirium (RR 1.41, 95% CI 0.60 to 3.33; 2 studies, 357 participants), and mobility (MD -0.40, 95% CI -0.96 to 0.16, favours THA; 1 study, 83 participants). We are unsure of the effect for early functional status, ADL, HRQoL, and mortality, which indicated little or no difference between interventions, because the certainty of the evidence was very low. The overall risks of adverse events were similar. There was an increased risk of dislocation with THA (RR 1.96, 95% CI 1.17 to 3.27; 12 studies, 2719 participants) and no evidence of a difference in deep infection.
For people undergoing HA for intracapsular hip fracture, it is likely that a cemented prosthesis will yield an improved global outcome, particularly in terms of HRQoL and mortality. There is no evidence to suggest a bipolar HA is superior to a unipolar prosthesis. Any benefit of THA compared with hemiarthroplasty is likely to be small and not clinically appreciable. We encourage researchers to focus on alternative implants in current clinical practice, such as dual-mobility bearings, for which there is limited available evidence.
Background
To achieve sufficient socket coverage by the native bone, high placement of cementless acetabular cup is often required. We previously reported, using computer simulation, that higher hip ...centre improved the bone coverage but decreased the range of motion in total hip arthroplasty (THA) for patients with hip dysplasia. However, in a clinical setting, the correlation between the hip centre height and dislocation after primary THA is still unclear. We examined whether a high hip centre affects dislocation after THA.
Methods
A total of 910 patients, with 1079 dysplastic hips, who underwent primary THA were retrospectively reviewed. The age at THA averaged 63.0 years and mean follow-up was 74.3 months. Vertical centre of rotation (V-COR) was defined as the distance from the head centre to the interteardrop line. Uni- and multivariate logistic regression models were applied to identify significant factors affecting dislocation.
Results
Ten hips in nine patients (0.9%) had dislocation after THA. In univariate analysis, age at surgery and V-COR were significant risk factors for dislocation. Multivariate analysis identified advanced age at operation (odds ratio OR 1.8/5 years), Crowe classification (OR 15.6), V-COR (OR 3.1/5 mm), and femoral head size (OR 11.6) as independent risk factors for dislocation. Receiver operating characteristic curve analysis revealed the cutoff value of the V-COR for dislocation as 23.9 mm.
Conclusions
A higher hip centre with the V-COR > 23.9 mm affected dislocation after THA for DDH. Our results would be useful for reconstruction of the hip centre, particularly with cementless acetabular cups.
Background
Hip dysplasia represents a spectrum of complex deformities on both sides of the joint. Although many studies have described the acetabular side of the deformity, to our knowledge, little ...is known about the three-dimensional (3-D) head and neck offset differences of the femora of dysplastic hips. A thorough knowledge of proximal femoral anatomy is important to prevent potential impingement and improve results after acetabular reorientation.
Questions/purposes
(1) Are there common proximal femoral characteristics in patients with symptomatic hip dysplasia undergoing periacetabular osteotomy (PAO)? (2) Where is the location of maximal femoral head and neck offset deformity in hip dysplasia? (3) Do certain subgroups of dysplastic hips more commonly have cam-type femoral morphology? (4) Is there a relationship between hip ROM as well as impingement testing and 3-D head and neck offset deformity?
Methods
Using our hip preservation database, 153 hips (148 patients) underwent PAO from October 2013 to July 2015. We identified 103 hips in 100 patients with acetabular dysplasia (lateral center-edge angle LCEA < 20°) and who had a Tönnis grade of 0 or 1. Eighty-six patients (86%) underwent preoperative low-dose pelvic CT scans at our institution as part of the preoperative planning for PAO. It is currently our standard to obtain preoperative low-dose pelvic CT scans (0.75–1.25 mSv, equivalent to three to five AP pelvis radiographs) on all patients before they undergo PAO unless a prior CT scan is performed at an outside institution. Hips with a history of a neuromuscular disorder, prior trauma, prior surgery, radiographic evidence of joint degeneration, ischemic necrosis, or Perthes-like deformities were excluded. Fifty hips in 50 patients met inclusion criteria and had CT scans available for review. Hips were analyzed with Dyonics Plan software and characterized with regard to version, neck-shaft angle, femoral head diameter, head and neck offset, femoral neck length, femoral offset, head center height, trochanteric height, and alpha angle. The maximum head and neck offset deformity was assessed using an entire clockface and an alpha angle ≥ 55° defined coexisting cam morphology. Subgroups included severity of lateral dysplasia: mild (LCEA 15°–20°) and moderate/severe (LCEA < 15°). Femoral version subgroups were defined as normal (5°–20°), decreased (≤ 5°), or increased (> 20°). The senior author (JCC) performed all physical examination testing.
Results
The mean LCEA was 14° (±4°), whereas the mean femoral anteversion was 19° (±12°). Eight hips (16%) demonstrated relative femoral retroversion (≤ 5°), whereas 26 (52%) showed excessive femoral anteversion (> 20°). Four hips (8%) had ≥ 35° of femoral anteversion. The mean neck-shaft angle was 136° (±5°). The mean maximum alpha location was 2:00 o’clock (±45 minutes) and the mean maximum alpha angle was 52° (±6°). Minimum head-neck offset ratio was located at 1:30 with a mean of 0.14 (±0.03). An anterior head-neck offset ratio of ≤ 0.17 or an alpha angle ≥ 55° was found in 43 (86%) of hips. Twenty-one dysplastic hips (42%) had an alpha angle ≥ 55°. Mildly dysplastic hips had decreased femoral head and neck offset (9 ± 1) and head and neck offset ratio (0.20 ± 0.03) at 12 o’clock compared with moderate/severe dysplastic hips (10 ± 1 and 0.22 ± 0.03, respectively; p = 0.04 and p = 0.01). With the numbers available, we found that hips with excessive femoral anteversion (> 20°) had no difference in the alpha angle at 3 o’clock (42 ± 7) compared with hips with relative femoral retroversion (≤ 5°; 48 ± 4; p = 0.06). No other differences in femoral morphology were found between hips with mild or moderate/severe dysplasia or in the femoral version subgroups with the numbers available. Anterior impingement test was positive in 76% of hips with an alpha angle ≥ 55° and 83% of the hips with an alpha angle ≤ 55°. No correlation was found between proximal femoral morphology and preoperative ROM.
Conclusions
In this subset of dysplastic hips, cam deformity of the femoral head and neck was present in 42% of hips with maximal head-neck deformity at 2 o’clock, and 82% had reduced head-neck offset at the 1:30 point. We conclude that cam-type deformities and decreased head-neck offset in developmental dysplasia of the hip are common. Patients should be closely assessed for need of a head and neck osteochondroplasty, especially after acetabular correction. Future prospective studies should evaluate the influence of proximal femoral anatomy on surgical results of PAO for dysplastic hips.
Level of Evidence
Level IV, prognostic study.
Dual Mobility in Total Hip Arthroplasty Plummer, Darren R., MBA; Haughom, Bryan D., MD; Della Valle, Craig J., MD
The Orthopedic clinics of North America,
2014, January 2014, 2014-Jan, 2014-01-00, 20140101, Letnik:
45, Številka:
1
Journal Article
Recenzirano
Dual-mobility articulations have shown promising results. Postoperative instability remains the most common reason for revision of a total hip arthroplasty (THA). Dual-mobility cups have been shown ...to decrease the rate of dislocation in primary THA and have been used to treat and prevent instability in revision THA. Greater range of motion and a greater head-to-neck ratio and a greater jump distance are achieved, resulting in a lower risk of instability. Concerns with dual-mobility cups include wear and intraprosthetic dislocation. Specific design modifications have aimed to improve cup fixation and decrease polyethylene wear and the risks of intraprosthetic dislocation.
Bilateral THAs performed in the same patient should not be considered independent observations, neither biologically nor statistically. As a result, when surgical results are reviewed, it is common ...to analyze only the first of the two hips, assuming that the first, and not the second hip of a staged bilateral THA, better resembles unilateral THAs. This assumption has not been empirically justified.Question/purposes (1) In patients with staged bilateral THA, is the first or second hip more similar to a unilateral THA in terms of age at surgery, presence of any preoperative Charlson comorbidity, and risk of postoperative reoperation? (2) Should the date of a first or second hip surgery of a staged bilateral THA be used as a starting point for patient survival to better resemble patients with unilateral THA?
We identified 68,357 THAs due to osteoarthritis in 63,613 patients from the Swedish Hip Arthroplasty Register (SHAR) in 1999-2015. Of those THAs, 14,780 concerned the first hip of a staged bilateral procedure performed between 1999 and 2004; 28,542 were unilaterals from 2004 to 2008, and 25,035 concerned the second hip of a staged bilateral procedure performed 2008 to 2015. We excluded patients who underwent one-stage bilateral THAs. We used different inclusion periods to distinguish unilateral procedures from the first and second hips from staged bilateral procedures because sufficiently long set-up and follow-up periods were needed before and after each period to identify possible contralateral THAs. This introduced potential period confounding, meaning that possible group differences might not be distinguished from unrelated outcome differences over time. We investigated if such time trends existed. It did not for age and reoperation rates, but it did for comorbidity and patient survival. Our primary study endpoint was whether patients with unilateral THAs were more similar to patients with a first hip of a staged bilateral THA, or to patients with their second hip operated. We used Student's t-test to compare mean age at surgery. The proportion of patients with at least one presurgery Charlson comorbidity were compared by 95% bootstrap confidence intervals, after subtracting the yearly time-trend to avoid period confounding. Postoperative risks of reoperation were compared by log-rank tests of Kaplan-Meier curves and by comparing 5-year reoperation rates by pair-wise 95% CIs. Our secondary study endpoint was to compare patient survival for patients with a unilateral THA, a first hip of a staged bilateral THA, or a second hip of a staged bilateral THA. We evaluated this by relative 5-year survival, comparing patients of each group with the general Swedish population of the same age, sex, and year of birth. This way, possible survival differences would be less likely explained by period confounding.
Patients undergoing unilateral THA were older than those undergoing a first hip of a staged bilateral THA (70 ± 10 versus 66 ± 9 years, mean difference of 4; p < .001), but they were not different from patients undergoing the second hip of a staged bilateral THA (70 ± 9 years, mean difference of 0; p = 0.74). The period-adjusted proportion of patients with unilateral THA and presurgery comorbidity (Charlson index > 0) was 20% (95% CI: 19.8-20.7). This was no different from patients with a second hip from a staged bilateral THA (20%; 19.7-20.6), but higher compared to patients with a first hip of a staged bilateral THA (15%; 14.5-15.4). For reoperation rates, the log-rank tests showed no difference between unilateral THAs and the second hips of staged bilateral THAs ((Equation is included in full-text article.)). Such difference was found for unilaterals compared with the first hips of staged bilateral THAs ((Equation is included in full-text article.)). The Kaplan-Meier estimate of reoperation rates at 5 years after surgery were also no different for the unilateral THAs compared with the second hips of staged bilateral THAs (3% 95% CI 2.8 to 3.2 for both groups). It was lower (2% 95% CI 1.8 to 2.3) for a first hip of a staged bilateral THA. For the secondary outcome, the relative 5-year survival differed for all groups. It was 105% (95% CI 104.9 to 105.9) for patients with unilateral THA, 107% (95% CI 106.3 to 107.4) for patients with a second hip from a staged bilateral THA and 109% (95% CI 108.8 to 109.5) for patients with a first hip of a staged bilateral THA. Patients with only a first hip of a planned staged bilateral THA who did not survive long enough to undergo their second THA were classified as unilaterals. The rank-order of survival curves are therefore by design ("immortal time bias"). We conclude, however, that survival for patients with unilateral THA more closely resembles the survival of patients with a second hip of a staged bilateral THA, compared with the first.
Our findings, which are based on observational register data, challenge the common practice in epidemiologic studies of analyzing only the first hip of a staged bilateral THA. We recommend analyzing the second THA in a patient who has undergone staged bilateral THA rather than the first because the second procedure better resembles unilateral THA.
Level III, therapeutic study.
PDF
