There are limited long-term studies reporting on outcomes of the Zimmer Modular Revision (ZMR) stem, and concerns remain regarding failure. Our primary aim was to determine long-term survival free from all-cause revision and stem-related failure for this modular revision stem in revision total hip arthroplasty (THA). Secondary aims included evaluating radiological and functional outcomes. We retrospectively identified all patients in our institutional database who underwent revision THA using the ZMR system from January 2000 to December 2007. We included 106 patients (108 hips) with a mean follow-up of 14.5 years (2.3 to 22.3). Mean patient age was 69.2 years (37.0 to 89.4), and 51.9% were female (n = 55). Indications for index revision included aseptic loosening (73.1%), infection (16.7%), fracture (9.3%), and stem fracture (0.9%). Kaplan-Meier analysis was used to determine the all-cause and stem-related failure revision-free survival. At most recent follow-up, Oxford Hip Scores (OHS) were collected, and radiological stem stability was determined using the Engh classification.Aims
Methods
The purpose of this study was to determine long-term survival free from all-cause revision and stem-related failure, as well as radiographic and functional outcomes of the ZMR stem in revision THA. We retrospectively identified all patients in our institutional database who underwent revision THA using the ZMR Revision Hip system from the year 2000 to 2007 (minimum two-year follow-up). Of the 112 ZMR hips (110 patients) identified, a total of 106 hips (104 patients) met inclusion criteria. The mean study follow-up 13.9 years (range 2–22). Indications for index ZMR revision included aseptic loosening (72.1%), periprosthetic joint infection (17.3%), periprosthetic fracture (9.6%), and stem fracture (1.0%). Kaplan-Meier analysis was used to determine the all-cause and stem-related failure revision-free survival. Validated patient reported outcomes were collected and available radiographs were reviewed to determine implant stability. A total of 17 hips (16.0%) underwent a re-revision of any component. The indications for re-revision were stem failure (35.3%), infection (29.4%), instability (29.4%), and aseptic loosening of the acetabular component (5.9%). The five- and 15-year all-cause survivorship was 89.5% (95% CI 86.5–92.5) and 83.0% (95% CI 79.2–86.8), respectively. There were six re-revisions for stem failure (5.7%); five for stem fracture and one for aseptic loosening. The average time to stem failure was 4.6 years (range 1.3–8.2). The five- and 15-year survivorship free from stem-related failure was 97.2% (95% CI 95.6–98.8) and 93.9% (95% CI 91.5–96.3), respectively. At final follow-up the mean Oxford hip score was 36.9 and all surviving ZMR stems were well fixed on radiographs. Femoral revision with the ZMR stem offers satisfactory long-term survivorship and promising clinical outcomes. Although uncommon, stem fracture was the most common reason for stem-related failure.
Hip resurfacing remains a potentially valuable surgical procedure for appropriately-selected patients with optimised implant choices. However, concern regarding high early failure rates continues to undermine confidence in use. A large contributor to failure is adverse local tissue reactions around metal-on-metal (MoM) bearing surfaces. Such phenomena have been well-explored around MoM total hip arthroplasties, but comparable data in equivalent hip resurfacing procedures is lacking. In order to define genetic predisposition, we performed a case-control study investigating the role of human leucocyte antigen (HLA) genotype in the development of pseudotumours around MoM hip resurfacings. A matched case-control study was performed using the prospectively-collected database at the host institution. In all, 16 MoM hip resurfacing 'cases' were identified as having symptomatic periprosthetic pseudotumours on preoperative metal artefact reduction sequence (MARS) MRI, and were subsequently histologically confirmed as high-grade aseptic lymphocyte-dominated vasculitis-associated lesions (ALVALs) at revision surgery. ‘Controls’ were matched by implant type in the absence of evidence of pseudotumour. Blood samples from all cases and controls were collected prospectively for high resolution genetic a nalysis targeting 11 separate HLA loci. Statistical significance was set at 0.10 a priori to determine the association between HLA genotype and pseudotumour formation, given the small sample size.Aims
Methods
Several short- and mid-term studies have shown minimal liner wear of highly cross-linked polyethylene (HXLPE) in total hip arthroplasty (THA), but the safety of using thinner HXLPE liners to maximize femoral head size remains uncertain. The objective of this study was to analyze clinical survival and radiological wear rates of patients with HXLPE liners, a 36 mm femoral head, and a small acetabular component with a minimum of ten years’ follow-up. We retrospectively identified 55 patients who underwent primary THA performed at a single centre, using HXLPE liners with 36 mm cobalt-chrome heads in acetabular components with an outer diameter of 52 mm or smaller. Patient demographic details, implant details, death, and all-cause revisions were recorded. Cox regression and Kaplan-Meier survival was used to determine all-cause and liner-specific revision. Of these 55 patients, 22 had a minimum radiological follow-up of seven years and were assessed radiologically for linear and volumetric wear.Aims
Methods
Our objective is to describe early and midterm results with the use of a new knee prosthesis as an articulating spacer in planned two-stage management for infected total knee arthroplasty. As a second objective, we compared outcomes between the group with a retained first stage and those with a completed 2-stage revision. Forty-seven patients (48 knees) from January 2012 and November 2017 underwent a 2-stage exchange with an articulating spacer with new implants was used for a chronic knee periprosthetic joint infection with a mean follow-up of 3.7 years (2–6.5 years). The most frequently identified infecting organism was MSSA (31%), MRSA (21%) or MRSE (20%). At the first stage, a new PS femoral component and a new all-polyethylene posterior stabilized (PS) tibial component or a standard PS tibial liner were cemented with antibiotic-cement, typically 3.6 gm tobramycin and vancomycin 1.5 gm. IV antibiotics for six weeks were administered. The planned reimplantation was at 3 months, but ninetteen spacers (14 all poly tibias and 5 tibial liner) were retained for over 12 months. Postoperative assessment included knee range of motion (ROM), quality of life (QOL) scores (SF-12, WOMAC, KOOS, Oxford, and UCLA scores), and a satisfaction scale from 0–100%.Introduction
Methods
Our objective is to describe our early and mid-term results with the use of a new simple primary knee prosthesis as an articulating spacer in planned two-stage management for infected knee arthroplasty. As a second objective, we compared outcomes between the group with a retained first stage and those with a complete two-stage revision. We included 47 patients (48 knees) with positive criteria for infection, with a minimum two-year follow-up, in which a two-stage approach with an articulating spacer with new implants was used. Patients with infection control, and a stable and functional knee were allowed to retain the initial first-stage components. Outcomes recorded included: infection control rate, reoperations, final range of motion (ROM), and quality of life assessment (QoL) including Western Ontario and McMaster Universities osteoarthritis index, Knee Injury and Osteoarthritis Outcome Score, Oxford Knee Score, 12-Item Short-Form Health Survey questionnaire, and University of California Los Angeles (UCLA) activity score and satisfaction score. These outcomes were evaluated and compared to additional cohorts of patients with retained first-stage interventions and those with a complete two-stage revision. Mean follow-up was 3.7 years (2.0 to 6.5).Aims
Methods
The practice of overlapping surgery has been increasing in the delivery of orthopaedic surgery, aiming to provide efficient, high-quality care. However, there are concerns about the safety of this practice. The purpose of this study was to examine the safety and efficacy of a model of partially overlapping surgery that we termed ‘swing room’ in the practice of primary total hip (THA) and knee arthroplasty (TKA). A retrospective review of prospectively collected data was carried out on patients who underwent primary THA and TKA between 2006 and 2017 in two academic centres. Cases were stratified as partially overlapping (swing room), in which the surgeon is in one operating room (OR) while the next patient is being prepared in another, or nonoverlapping surgery. The demographic details of the patients which were collected included operating time, length of stay (LOS), postoperative complications within six weeks of the procedure, unplanned hospital readmissions, and unplanned reoperations. Fisher's exact, Wilcoxon rank-sum tests, chi-squared tests, and logistic regression analysis were used for statistical analysis.Aims
Methods
The number of medial unicompartmental knee replacements (UKR) performed for arthritis has increased and as such, revisions to total knee replacement (TKR) is increasing. Previous studies have investigated survivorship of UKR to TKR revision and functional outcomes compared to TKR to TKR revision, but have failed to detail the surgical considerations involved in these revisions. Our objectives are to investigate the detailed surgical considerations involved in UKR to TKR revisions. This study is a retrospective comparative analysis of a prospectively collected database. From 2005 to 2017, 61 revisions of UKR to TKR were completed at a single center. Our inclusion criteria included: revision of UKR to TKR or TKR to TKR with minimum 1 year follow-up. Our exclusion criteria include: single component and liner revisions and revision for infection. The 61 UKR to TKR revisions were matched 2:1 with respect to age, ASA and BMI to a group of 122 TKR to TKR revisions. The following data was collected: indication for and time to revision, operative skin to skin surgical time, the use of specialized equipment (augment size/location, stem use), intraoperative and postoperative complications, re-operations and outcome scores (WOMAC, Oxford 12, SF 12, satisfaction score).Introduction
Methods
The practice of overlapping surgery has been increasing in the delivery of orthopaedic care, aiming to provide efficient, high-quality care. However, there have been concerns about the safety of this practice. The purpose of this study is to examine safety and efficacy of a model of partially overlapping surgery that we termed “the swing room” in practice in primary hip and knee arthroplasty. A retrospective review of prospectively collected data using an administrative database was carried out on patients who underwent primary unilateral total hip and total knee arthroplasty from 2006 to 2017 at two sites of one academic center staffed by four arthroplasty surgeons. All revisions and bilateral primary procedures were excluded. Cases were stratified as overlapping or non-overlapping. Overlapping was defined when a surgeon had access to two operating rooms with two teams, and non-overlapping was defined as when a surgeon only had access to a single operating room on a particular day. Patient demographic characteristics, operating room time, procedure time, length of stay, Postoperative complications within 30 days of the procedure, unplanned hospital readmissions, unplanned reoperations, and emergency department visits were collected. The Fisher's exact Wilcoxon rank-sum test and logistic regression analysis were used for statistical analysis.Introduction
Methods
We investigated the long-term performance of the Tripolar Trident acetabular component used for recurrent dislocation in revision total hip arthroplasty. We assessed: 1) rate of re-dislocation; 2) incidence of complications requiring re-operation; and 3) Western Ontario and McMaster Universities osteoarthritis index (WOMAC) pain and functional scores. We retrospectively identified 111 patients who had 113 revision tripolar constrained liners between 1994 and 2008. All patients had undergone revision hip arthroplasty before the constrained liner was used: 13 after the first revision, 17 after the second, 38 after the third, and 45 after more than three revisions. A total of 75 hips (73 patients) were treated with Tripolar liners due to recurrent instability with abductor deficiency, In addition, six patients had associated cerebral palsy, four had poliomyelitis, two had multiple sclerosis, two had spina bifida, two had spondyloepiphyseal dysplasia, one had previous reversal of an arthrodesis, and 21 had proximal femoral replacements. The mean age of patients at time of Tripolar insertions was 72 years (53 to 89); there were 69 female patients (two bilateral) and 42 male patients. All patients were followed up for a mean of 15 years (10 to 24). Overall, 55 patients (57 hips) died between April 2011 and February 2018, at a mean of 167 months (122 to 217) following their tripolar liner implantation. We extracted demographics, implant data, rate of dislocations, and incidence of other complications.Aims
Patients and Methods
Fully constrained liners are used to treat recurrent dislocations or patients at high risk after total hip replacements. However, they can cause significant morbidities including recurrent dislocations, infections, aseptic loosening and fractures. We examine long term results of 111 patients with tripolar constrained components to assess their redislocation and failure rate. The purpose of this study was to assess survivorship, complications and functional outcomes at a minimum 10 years after the constrained tripolar liners used in our institute.Background
Questions/purposes
High complication rates and poor outcomes have been widely reported in patients undergoing revision of large head metal-on-metal arthroplasty. A previous study from our center showed high rates of dislocation, nerve injury, early cup loosening and pseudotumor recurrence. After noting these issues, we implemented the following changes in surgical protocol in all large head MOM revisions: 1. Use of highly porous shells in all cases 2. Use of largest femoral head possible 3. Low threshold for use of dual mobility and constrained liners when abductors affected or absent posterior capsule 4. Use of ceramic head with titanium sleeve in all cases 5. Partial resection of pseudotumor adjacent to sciatic and femoral nerves. The purpose of the present study is to compare the new surgical protocol above to our previously reported early complications in this group of patients We specifically looked at (1) complications including reoperations; (2) radiologic outcomes; and (3) functional outcomes. Complication rates after (Group 1), and before (Group 2) modified surgical protocol were compared using Chi-square test, assuming statistical significance p<0.05.Background
Questions/purposes
Pseudotumor or high grade ALVAL (aseptic lymphocyte-dominated vasculitis-associated lesion) development around total hip replacements secondary to local metal debris generation – especially in the setting of metal-on-metal bearings – is a well-recognised histopathologic phenomenon. Recent work has suggested a strong genetic correlation with an individual's risk of such lesion development following metal exposure. Emerging data have highlighted a similar potential concern around total knee replacements (TKRs), particularly with increasing construct modularity. To date, the body-of-knowledge pertaining to TKR-associated ALVALs has largely been limited to individual case reports or small retrospective case series’, with no large-scale investigation looking at this potential complication. This study sought to establish the preliminary prevalence of pseudotumor or high grade ALVAL formation seen at the revision of primary TKRs and to establish the correlation between histologic ALVAL grade and patient-reported functional outcomes. Findings of 1263 consecutive patients undergoing revision knee surgery, at a high-volume referral center, were reviewed. 161 cases of active infection were excluded. Complete histopathology reports were subsequently available for 321 (29.1%) non-infective cases. Each case was independently histologically-classified using a previously validated scoring system reflecting ALVAL grade. Post-operative patient-reported outcomes measures (PROMs) were available for 134 patients (41.7%), allowing direct correlation between functional performance and the established histopathology results.Background
Methods
Fretting and corrosion at the modular head/neck junction, known
as trunnionosis, in total hip arthroplasty (THA) is a cause of adverse
reaction to metal debris (ARMD). We describe the outcome of revision
of metal-on-polyethylene (MoP) THA for ARMD due to trunnionosis
with emphasis on the risk of major complications. A total of 36 patients with a MoP THA who underwent revision
for ARMD due to trunnionosis were identified. Three were excluded
as their revision had been to another metal head. The remaining
33 were revised to a ceramic head with a titanium sleeve. We describe
the presentation, revision findings, and risk of complications in
these patients.Aims
Patients and Methods
Fractures around total knee arthroplasties pose
a significant surgical challenge. Most can be managed with osteosynthesis
and salvage of the replacement. The techniques of fixation of these
fractures and revision surgery have evolved and so has the assessment
of outcome. This specialty update summarises the current evidence
for the classification, methods of fixation, revision surgery and
outcomes of the management of periprosthetic fractures associated
with total knee arthroplasty. Cite this article:
Reconstruction of the acetabulum after failed total hip arthroplasty
(THA) can be a surgical challenge in the presence of severe bone
loss. We report the long-term survival of a porous tantalum revision
acetabular component, its radiological appearance and quality of
life outcomes. We reviewed the results of 46 patients who had undergone revision
of a failed acetabular component with a Paprosky II or III bone
defect and reconstruction with a hemispherical, tantalum acetabular
component, supplementary screws and a cemented polyethylene liner.Aims
Patients and Methods
We present a case series of ten metal-on-polyethylene total hip
arthroplasties (MoP THAs) with delayed dislocation associated with
unrecognised adverse local tissue reaction due to corrosion at the
trunnion and pseudotumour formation. The diagnosis was not suspected in nine of the ten patients (six
female/four male; mean age 66 years), despite treatment in a specialist
unit (mean time from index surgery to revision was 58 months, 36
to 84). It was identified at revision surgery and subsequently confirmed
by histological examination of resected tissue. Pre-operative assessment
and culture results ruled out infection. A variety of treatment
strategies were used, including resection of the pseudotumour and
efforts to avoid recurrent dislocation. Aims
Methods
Tapered fluted titanium stems are increasingly
used for femoral revision arthroplasty. They are available in modular and
non-modular forms. Modularity has advantages when the bone loss
is severe, the proximal femur is mis shapen or the surgeon is unfamiliar
with the implant, but it introduces the risk of fracture of the
stem at the junction between it and the proximal body segment. For
that reason, and while awaiting intermediate-term results of more recently
introduced designs of this junction, non-modularity has attracted
attention, at least for straightforward revision cases. We review the risks and causes of fracture of tapered titanium
modular revision stems and present an argument in favour of the
more selective use of modular designs. Cite this article:
Adverse reaction to wear and corrosion debris
is a cause for concern in total hip arthroplasty (THA). Modular junctions
are a potential source of such wear products and are associated
with secondary pseudotumour formation. We present a consecutive series of 17 patients treated at our
unit for this complication following metal-on-highly cross-linked
polyethylene (MoP) THA. We emphasise the risk of misdiagnosis as
infection, and present the aggregate laboratory results and pathological
findings in this series. The clinical presentation was pain, swelling or instability.
Solid, cystic and mixed soft-tissue lesions were noted on imaging
and confirmed intra-operatively. Corrosion at the head–neck junction
was noted in all cases. No bacteria were isolated on multiple pre-
and intra-operative samples yet the mean erythrocyte sedimentation
rate was 49 (9 to 100) and C-reactive protein 32 (0.6 to 106) and
stromal polymorphonuclear cell counts were noted in nine cases. Adverse soft–tissue reactions can occur in MoP THA owing to corrosion
products released from the head–neck junction. The diagnosis should
be carefully considered when investigating pain after THA. This
may avoid the misdiagnosis of periprosthetic infection with an unidentified
organism and mitigate the unnecessary management of these cases
with complete single- or two-stage exchange. Cite this article:
Non-modular tapered fluted, titanium stems are
available for use in femoral revision. The combination of taper
and flutes on the stem provides axial and rotational stability,
respectively. The material and surface properties of the stem promotes
bone on-growth. If the surgeon is confident and reasonably experienced
in the surgical use of this sort of design and the case is relatively
straightforward, a non-modular design is effective. It also potentially reduces
implant inventory, and circumvents the potential problems of taper
junction corrosion and fatigue fracture. There are reports of excellent
survival, good clinical and functional results and evidence of subsequent
increase in proximal bone stock. Cite this article: Bo
