High Risk Of Dislocation Research Articles

Use of morselized allografts for acetabular reconstruction during THA revision: French multicenter study of 508 cases with 8 years’ average follow-up

BackgroundIn the context of acetabular reconstruction, bone defects can be filled with processed or unprocessed bone allografts. Published data are often contradictory on this topic and few studies have been done comparing processed allografts to fresh-frozen ones. This led us to conduct a large study to measure the factors impacting the survival of THA revision: (1) type of allograft and cup, (2) technical factors or patient-related factors. HypothesisAcetabular reconstruction can be performed equally well with frozen or processed morselized allografts. Materials and methodsThis retrospective, multicenter study of acetabular reconstruction included 508 cases with a minimum follow-up of 5 years. The follow-up for the frozen grafts was shorter (7.86 years±1.89 [5–12.32]) than that of the processed grafts (8.22 years±1.77 [5.05–15.48]) (p=0.029). However, the patients were younger at the time of the primary THA procedure in the frozen allograft group (51.5 years±14.2 [17–80]) than in the processed group (57.5 years±13.0 [12–94]) (p<0.001) and were also younger at the time of THA revision (67.8 years±12.2 [36.9–89.3] versus 70 years±11.7 [25–94.5]) (p=0.041). ResultsThere were more complications overall in the frozen allograft group (46/242=19.0%) than the processed allograft group (35/256=13.2%) (p=0.044) with more instances of loosening in the frozen group (20/242 [8.2%]) than in the processed group (6/266 [3.3%])(p=0.001). Conversely, the dislocation rate (16/242=6.6% vs. 17/266=6.4%) (p=0.844) and infection rate (18/242=7.4% vs. 15/266=5.7%) (p=0.264) did not differ between groups. The subgroup analysis reveal a correlation between the occurrence of a complication and higher body mass index (BMI) (p=0.037) with a higher overall risk of complications in patients with a BMI above 30 or under 20 (p=0.006) and a relative risk of 1.95 (95% CI: 1.26–2.93). Being overweight was associated with a higher risk of dislocation (relative risk of 2.46; 95% CI: 1.23–4.70) (p=0.007). Loosening was more likely to occur in younger patients at the time of the procedure (relative risk of 2.77; 95% CI: 1.52–6.51) (p=0.040) before 60 years during the revision. Lastly, patients who were less active preoperatively based on the Devane scale had an increased risk of dislocation (relative risk of 2.51; 95% CI: 1.26–8.26) (p=0.022). DiscussionOur hypothesis was not confirmed. The groups were not comparable initially, which may explain the differences found since the larger number of loosening cases in the frozen allograft group can be attributed to group heterogeneity. Nevertheless, morselized allografts appear to be suitable for acetabular bone defect reconstruction. A randomized study would be needed to determine whether frozen or processed allografts are superior. Level of evidenceIII, comparative retrospective study.

The use of dual-mobility bearings in patients at high risk of dislocation.

Instability continues to be a troublesome complication after total hip arthroplasty (THA). Patient-related risk factors associated with a higher dislocation risk include the preoperative diagnosis, an age of 75 years or older, high body mass index (BMI), a history of alcohol abuse, and neurodegenerative diseases. The goal of this study was to assess the dislocation rate, radiographic outcomes, and complications of patients stratified as high-risk for dislocation who received a dual mobility (DM) bearing in a primary THA at a minimum follow-up of two years. We performed a retrospective review of a consecutive series of DM THA performed between 2010 and 2014 at our institution (Hospital for Special Surgery, New York, New York) by a single, high-volume orthopaedic surgeon employing a single prosthesis design (Anatomic Dual Mobility (ADM) Stryker, Mahwah, New Jersey). Patient medical records and radiographs were reviewed to confirm the type of implant used, to identify any preoperative risk factors for dislocation, and any complications. Radiographic analysis was performed to assess for signs of osteolysis or remodelling of the acetabulum. There were 151 patients who met the classification of high-risk according to the inclusion criteria and received DM THA during the study period. Mean age was 82 years old (73 to 95) and 114 patients (77.5%) were female. Mean follow-up was 3.6 years (1.9 to 6.1), with five patients lost to follow-up and one patient who died (for a reason unrelated to the index procedure). One patient (0.66%) sustained an intraprosthetic dislocation; there were no other dislocations. At mid-term follow-up, the use of a DM bearing for primary THA in patients at high risk of dislocation provided a stable reconstruction option with excellent radiographic results. Longer follow-up is needed to confirm the durability of these reconstructions.

The critical size of a defect in the glenoid causing anterior instability of the shoulder after a Bankart repair, under physiological joint loading.

Patients with recurrent anterior dislocation of the shoulder commonly have an anterior osseous defect of the glenoid. Once the defect reaches a critical size, stability may be restored by bone grafting. The critical size of this defect under non-physiological loading conditions has previously been identified as 20% of the length of the glenoid. As the stability of the shoulder is load-dependent, with higher joint forces leading to a loss of stability, the aim of this study was to determine the critical size of an osseous defect that leads to further anterior instability of the shoulder under physiological loading despite a Bankart repair. Two finite element (FE) models were used to determine the risk of dislocation of the shoulder during 30 activities of daily living (ADLs) for the intact glenoid and after creating anterior osseous defects of increasing magnitudes. A Bankart repair was simulated for each size of defect, and the shoulder was tested under loading conditions that replicate in vivo forces during these ADLs. The critical size of a defect was defined as the smallest osseous defect that leads to dislocation. The FE models showed a high risk of dislocation during ADLs after a Bankart repair for anterior defects corresponding to 16% of the length of the glenoid. This computational study suggests that bone grafting should be undertaken for an anterior osseous defect in the glenoid of more than 16% of its length rather than a solely soft-tissue procedure, in order to optimize stability by restoring the concavity of the glenoid.

PHACOEMULSIFICATION OF BROWN CATARACTS ON AVITREAL EYES

Analysis of the features of surgical treatment of brown cataracts in the eyes with previously performed posterior vitrectomy. The study included 25 patients (25 eyes) with nuclear cataracts 6+ density according to LOCS III classification. All patients underwent microinvasive posterior vitrectomy more than 6 months ago. Microcoaxial (2.2 mm) phacoemulsification of cataract with implantation of flexible intraocular lens was planned for all patients. In 15 patients (60 %), a system of capsule hooks was used in order to support the capsule bag 4 in 16 % of cases and 6 in 44 % of cases. Results and discussion. Sutureless surgery were performed in 24 patients (96 %). In one case with nigra cataract despite the use of capsule hooks, due to the high risk of dislocation of the lens into the vitreous cavity, the surgery was converted into a large incision. Microcoaxial phacoemulsification is the surgery of choice in the case of a combination of dense lens and lack of vitreous support. The use of capsular hooks greatly simplifies surgery and increases the chances of sutureless surgery.

Initial Diagnosis and Management for Acute Charcot Neuroarthropathy

Charcot neuroarthropathy, also known as Charcot foot, is a complication of diabetes mellitus where there is progressive degeneration of the joints, but it potentially is devastating in its consequences.1 It commonly affects the middle of the foot, hind-foot joints, the ankle, and forefoot joints, and it is believed to result from inflammation in the foot that becomes abnormally protracted due to the underlying neuropathy.2–8 The prevalence of Charcot neuroarthropathy is up to 13% in individuals with diabetes.9–11 Patients with Charcot neuroarthropathy encounter increased morbidity and decreased quality of life and mortality.2,4,5,12,13 If there is a delay in treatment, Charcot neuroarthropathy could result in ulceration and infection which can lead to amputation of the limb.12–16 These patients have a significant financial impact on the health care system through primary care, community care, outpatient costs, increased bed occupancy, and prolonged stays in hospital. Charcot neuroarthropathy poses many clinical challenges in its diagnosis and management. The often asymptomatic nature of the condition is very similar to ankle sprain, cellulitis, venous thrombosis, inflammatory arthritis, or gout in a healthy patient.5,16–22 Missed diagnosis is as high as 79% which ultimately leads to a delay in treatment for an average of 29 weeks.11,16,17,20,23–25 Charcot neuroarthropathy is caused by multiple factors, but essentially it is the result of peripheral neuropathy which is a complication associated with many diseases.2,4,5 The underlying peripheral neuropathy can skew the pain perception the patient experiences and can mislead the clinician on their differential diagnosis of an “inflamed foot”. A thorough neurological examination of the foot can uncover the underlying inflammatory and osteolytic disease process of Charcot neuroarthropathy.2,4,11,19,26–29 Early recognition and intervention is imperative to avoid the rapid progression toward permanent foot deformity, ulceration, and the possibility of limb loss.16,30,31 There are multiple review articles about Charcot neuroarthropathy2,11–13,16,23,25,28,32–34, but a lack of guidance on foot screen strategies for primary care and emergency room physicians. There is a need for a comprehensive guideline for initial diagnoses and management on foot care to advocate for increased awareness, thereby leading to earlier diagnosis and treatment by a multi-disciplinary team. In the current study, a thorough literature review of Charcot neuroarthropathy was conducted to evaluate efficacious methods of protocol design and potential barriers to implementation. The literature review also encompassed treatment goals for patients with Charcot neuroarthropathy. Based on the literature review, a foot screen strategies protocol for Charcot neuroarthropathy was devised by the authors and reported here. This protocol contains three parts: (1) pathophysiology of acute Charcot neuroarthropathy to highlight the relationship between the clinical findings and the development of the disease, (2) a comprehensive guideline on how to screen and evaluate Charcot neuroarthropathy, and (3) a brief overview on prevention of Charcot neuroarthropathy in patients with diabetes and other forms of peripheral neuropathy. Pathophysiology The underlying cause for Charcot neuroarthropathy is due to peripheral neuropathy, which is a loss of function of the nerves in the periphery of the body.2–4 The primary episode of inflammation can result from a number of factors, but ultimately leads to an increase in pro-inflammatory cytokines (interleukin-1β and tumor necrosis factor-α) which leads to receptor activator of the nuclear factor-κB ligand (RANKL-NFκB) pathway. Osteoclasts are activated leading to bone lysis followed by clearing of debris. In the presence of autonomic neuropathy, there is increased blood flow to the area, which acts to clear away bony material demineralizing the bone, cartilage, and soft tissue in the region.3 However, in the presence of diabetic neuropathy, the patient does not have the protective pain perception. Therefore, they continue to walk on the inflamed foot exacerbating the progressive pathway of osteolysis and osteopenia and weakening the pedal skeleton, leading to the high risk for dislocation and/or fracture.5–8,34,35

Are dual mobility cups associated with increased metal ions in the blood? Clinical study of nickel and chromium levels with 29 months’ follow-up

IntroductionDual mobility cups have become the implant of choice for older patients with a high risk of dislocation. However, to our knowledge, no study has explored the possibility of metal ion production with these implants that incorporate a polyethylene-on-metal bearing. This led us to conduct a prospective study to determine whether use of a dual mobility cup is accompanied by increased levels of nickel and chromium in the blood. HypothesisUse of a dual mobility cup is accompanied by an increase of nickel and chromium levels in the blood. MethodsBetween 2012 and 2015, 16 consecutive patients were enrolled in the study. They underwent primary hip arthroplasty with a ceramic Biolox™ head (CeramTec, Plochingen, Germany), Corail™ titanium alloy stem (DePuy Synthes, Saint Priest, France) and a Novae™ dual mobility cup (SERF, Décines-Charpieu, France) consisting of 19% chromium (Cr) and 13–15% nickel (Ni). Patients who had other potential sources of nickel or chromium in their body (joint implants, dental implants, etc.) were excluded. The blood levels (μg/L) of nickel and chromium were measured preoperatively and at 2 years’ follow-up by an independent laboratory (Biomnis) using inductively coupled plasma mass spectrometry. The upper limits set by the laboratory were<0.87μg/L for chromium and<1.0μg/L for nickel. AP and lateral X-rays of the pelvis were taken preoperatively and at each postoperative follow-up visit to look for signs of loosening. The Postel-Merle-d’Aubigné (PMA) score was determined preoperatively and at each postoperative follow-up visit. Surgical revision procedures for any cause were also documented. ResultsThe mean follow-up was 29 months [13–39]. Preoperatively, blood nickel ion levels were measured in 7 patients; they were below 1μg/L in 6 patients (86%) and at 1.5μg/L in 1 patient (14%). The mean preoperative chromium ion levels (n=7) was 0.2μg/L [0–0.8μg/L]. Postoperatively, all 16 enrolled patients had their blood ion levels checked at a mean follow-up of 29 months. The nickel ion levels averaged 1.69±1.49 [0.2–5.6] (with 4/16 having>2μg/L and 12/16>1μg/L) and the chromium ion levels averaged 0.5±0.11 [0.4–0.7] (with no patients>0.7μg/L). There were no signs of loosening or osteolysis on the follow-up radiographs. The mean PMA score at 2 years was 17.8 [17,18]. ConclusionWe found that dual mobility cups generate increased nickel but not chromium ions in the blood. The levels measured are comparable to those for other orthopedic implants such as spine implants. The clinical consequences of these increased levels are not known. Nevertheless, there were no clinical or radiological signs of loosening, although the follow-up was only 2 years. Level of evidenceIV, Cohort study.

The cost-effectiveness of dual mobility in a spinal deformity population with high risk of dislocation: a computer-based model.

The routine use of dual-mobility (DM) acetabular components in total hip arthroplasty (THA) may not be cost-effective, but an increasing number of patients undergoing THA have a coexisting spinal disorder, which increases the risk of postoperative instability, and these patients may benefit from DM articulations. This study seeks to examine the cost-effectiveness of DM components as an alternative to standard articulations in these patients. A decision analysis model was used to evaluate the cost-effectiveness of using DM components in patients who would be at high risk for dislocation within one year of THA. Direct and indirect costs of dislocation, incremental costs of using DM components, quality-adjusted life-year (QALY) values, and the probabilities of dislocation were derived from published data. The incremental cost-effectiveness ratio (ICER) was established with a willingness-to-pay threshold of $100 000/QALY. Sensitivity analysis was used to examine the impact of variation. In the base case, patients with a spinal deformity were modelled to have an 8% probability of dislocation following primary THA based on published clinical ranges. Sensitivity analysis revealed that, at its current average price ($1000), DM is cost-effective if it reduces the probability of dislocation to 0.9%. The threshold cost at which DM ceased being cost-effective was $1180, while the ICER associated with a DM THA was $71 000 per QALY. These results indicate that under specific clinical and economic thresholds, DM components are a cost-effective form of treatment for patients with spinal deformity who are at high risk of dislocation after THA. Cite this article: Bone Joint J 2018;100-B:1297-1302.

Do Cemented Dual-Mobility Cups Confer Stability for Patients at High Risk of Dislocation in Revision Total Hip Arthroplasty?

AbstractDislocation is among the most commonly reported complications following revision total hip arthroplasty. Dual-mobility bearings may lower the risk of dislocation. The authors report the results of a multicenter study evaluating the use of a dual-mobility acetabular cup design that was cemented into a metal shell as part of complex acetabular reconstructions or in cases where the risk of dislocation was felt to be high, such as isolated bearing exchanges. Eighteen patients were identified for being at high risk of dislocation who underwent cementation of a dual-mobility shell that is specifically made for cementation, into a fully porous metal revision acetabular cup (10 patients) or into a well-fixed cup at the time of revision without removal of the existing acetabular component (eight patients). Patients were assessed clinically and radiographically at a minimum of 2 years for the evidence of dislocation, revision surgery, and implant loosening. At a mean of 36 months (range, 25–56 months), one patient died and one was lost to follow-up. There were no known cases of hip dislocation. There was one repeat revision, for a deep infection treated with irrigation and debridement. The mean preoperative Harris Hip Score of 46 (range, 40–79) improved to a mean of 65 points (range, 41–97) at the most recent evaluation. Acetabular components were retained in 8 out of 18 cases and the dual-mobility shell was cemented into it. Cementation of a dual-mobility cup into a shell at the time of a revision surgery is a safe and reliable construct at minimum of 2 years for patients at high risk of dislocation. There were no complications related to the cementation of the cup into the metal shell. Longer follow-up is required to further assess the durability of this construct.

Catastrophic failure of tripolar constrained liners due to backside wear: a novel failure mode

Constrained acetabular liners have been developed for patients who are at high risk for dislocation or who are undergoing revision surgery for recurrent dislocations. We report on 2 cases of failure of tripolar constrained liners due to severe backside polyethylene wear after dissociation of the outer polyethylene liner without dislocation, a mode of failure not previously reported. The backside of the inserts suffered severe polyethylene deformation, wear, and scratching due to dissociation from the locking mechanism. In patients with tripolar constrained liners, radiographic evidence of eccentric wear should be considered as possible occult dissociation of the polyethylene liner within the shell. Conversion to a modular dual mobility liner appears to be a viable solution in this setting.

Body mass index, hip function and surgeon volume are independent predictors of dislocation: an analysis of 4334 total hip replacements.

The aim of this study was to identify pre-operative and intra-operative factors that are predictive of dislocation following primary total hip replacement (THR). Data were prospectively collected for a consecutive series of 4334 THRs undertaken over a 14-year period. Ninety-eight (2.3%) of the 4334 patients had one or more dislocation post-operatively. A body mass index (BMI) of ≥35 (p<0.001), a Harris Hip Score (HHS) of ≤41 (p<0.001) and a low-volume surgeon (p<0.001), which was defined as performing fewer than 43 THRs per annum, were identified as independent predictors of dislocation using logistic regression analysis. Using these three variables in differing combinations the risk of dislocation varied from 0.5 to 10.4%. Patients at high risk of dislocation, with a BMI of ≥35 and a pre-operative HHS of ≤41, undergoing surgery by a low-volume surgeon had a dislocation rate of 10.5%, but this decreased to 2.3% when operated on by a high-volume surgeon. These risk factors could be used to identify patients at high risk of dislocation, and modification of these factors, such as weight loss to achieve a BMI of ≤35 or referral to a high-volume surgeon, may decrease the risk of dislocation and the resulting secondary morbidity.

Total Hip Arthroplasty Patients With Fixed Spinopelvic Alignment Are at Higher Risk of Hip Dislocation

BackgroundSitting radiographs have been used as a pre-operative tool to plan patient-specific total hip arthroplasty (THA) component position that would improve hip stability. Previous work has demonstrated that spinal mobility may impact functional acetabular position when seated. We sought to determine whether patients who dislocate following THA have different sitting spinopelvic alignment or acetabular component orientation compared to patients who did not dislocate. MethodsA consecutive series of 1000 patients underwent post-operative low-dose biplanar spine-to-ankle lateral radiographs in standing and sitting positions 1 year following THA. Twelve patients (1% of all patients) experienced hip dislocation. Patients were categorized as having normal lumbar spines (without radiographic arthrosis) or as having lumbar multi-level degenerative disc disease. Measurements of spinopelvic alignment parameters (including sacral slope, lumbar lordosis, and proximal femur angles) and acetabular component orientation in sitting position (functional inclination and functional anteversion) were performed. ResultsPatients who dislocated had significantly less spine flexion, less change in pelvic tilt, and more hip flexion from standing to sitting positions compared to patients with normal spines. In sitting position, dislocators had acetabular components with less functional inclination and less functional anteversion. ConclusionThis study demonstrates that patients with fixed spinopelvic alignment from standing to sitting position are at higher risk of hip dislocation. Imaging patients from standing to sitting position using this technique can provide valuable information on whether a patient has fixed spinopelvic alignment with postural changes and is therefore at higher risk of dislocation.

Outcomes of Modular Dual Mobility Acetabular Components in Revision Total Hip Arthroplasty

BackgroundThere is a high rate of dislocation after revision total hip arthroplasty. This study evaluated the outcomes of 1 modular dual mobility component in revision total hip arthroplasty in patients at high risk of dislocation. MethodsWe reviewed 64 revisions performed in 27 (42%) patients for recurrent dislocation, 16 (25%) for adverse local tissue reaction, 11 (17%) for reimplantation infection, and 10 (16%) for aseptic loosening, malposition, or fracture. Complications, reoperations, and survivorship were evaluated. ResultsThree-year survival was 98% with failure defined as aseptic loosening and 91% with failure as cup removal for any reason. With mean follow-up time of 38 months, there were 14 complications, including 2 dislocations treated with closed reduction, 9 infections, and 12 reoperations. All complications occurred in patients revised for instability, adverse local tissue reaction, or infection. ConclusionThe early results of this component are promising, with good overall survival and low rate of dislocation.

Total hip arthroplasty via the direct anterior approach with a dual mobility cup for displaced femoral neck fracture in patients with a high risk of dislocation.

Introduction: Although total hip arthroplasty (THA) is superior to bipolar hemiarthroplasty (BHA) for displaced femoral neck fracture in terms of hip pain, function and reoperation rate, THA has a higher rate of dislocation. The direct anterior approach (DAA) and a dual mobility cup (DMC) are associated with lower rates of dislocation. The aim of this study was to investigate the outcomes of THA compared with BHA, and in those patients who had a THA we investigated those with a DMC (DMC-THA) and compared them with those had a single conventional cup (Single cup-THA). Materials: A total of 89 patients living independently were included between 2009 and 2015. We assessed patient characteristics, peri- and post-operative outcomes, walking ability and one-year mortality. Adjusted odds ratios (Adjusted ORs) were estimated for decrease of walking ability and one-year mortality using a logistic regression model with adjustment for potential confounders such as age, neuromuscular diseases with weakness, duration of surgery, perioperative blood loss and preoperative walking ability. Results: BHA (20 patients) versus THA (69 patients): There was no significant difference in the walking ability in either group. Multivariable logistic regression analysis demonstrated a significant association with one-year mortality in both groups [THA Adjusted ORs 0.088 (95% CI 0.0007–0.69); p = 0.020]. Single cup-THA (36 patients) versus DMC-THA (33 patients): The DMC-THA group had significantly greater age and more patients with neuromuscular diseases with weakness compared with the Single cup-THA group. Multivariable logistic regression analysis demonstrated no significant difference in the decrease of walking ability and in the one-year mortality between the groups. There were no post operative dislocations in any group. Discussion: THA via the DAA is one of the best treatments for displaced femoral neck fracture with a low risk of dislocation. THA via the DAA with a DMC is a safe and effective treatment for the patients with a high risk of dislocation.

The Direct Anterior Approach for Complex Primary Total Hip Arthroplasty: The Extensile Acetabular Approach on a Regular Operating Room Table

BackgroundThe direct anterior approach on a regular operating room table has been reported with low dislocation rates. This might be beneficial for complex primary total hip arthroplasty (THA) such as in patients with cerebral palsy or following femoral or pelvic osteotomies. Extending the approach is often required to overcome problems such as acetabular deformities or severe contractures. MethodsWe retrospectively evaluated the results and complications of 29 patients with 37 complex primary THA in which an extensile approach was used. The extensile approach is described. Functional scores were collected in case the patient was ambulatory independently (n = 17). ResultsThe average age was 35 years (range 15-85) with a mean follow-up of 39 months (range 12-60). There were 3 (8%) intra-operative and 4 (11%) early post-operative complications (<3 months), of which 3 (8%) were anterior dislocations. Late complications (>3 months) consisted of a fibrous ingrown stem, a socket loosening following a pelvic fracture, and a late hematogenous infection (8%). Seventy-one percent of the complications occurred in the first 18 cases (49%) indicating a learning curve. The mean post-operative Harris Hip Score was 79 (range 56-97). ConclusionComplex THA can be safely conducted through the extensile anterior approach on a regular operating room table with the use of conventional implants, even in cases with a high risk of dislocation.

CORR Insights®: Nonmodular Tapered Fluted Titanium Stems Osseointegrate Reliably at Short Term in Revision THAs.

CORR Insights®: Nonmodular Tapered Fluted Titanium Stems Osseointegrate Reliably at Short Term in Revision THAs.

Midterm survivorship of the Lefèvre constrained liner: A consecutive single-centre multi-surgeon series of 166 cases

Introduction Constrained liners are used as part of a salvage procedure to provide stability for patients at high risk for dislocation following a total hip arthroplasty. However, no recent studies exist highlighting their effectiveness and or limitations. Method This prospective review included 166 consecutive hip arthroplasties, either primary (27%) or revision (73%), with a unique design of a constrained liner Lefevre retentive cup. There were 113 females (69%) and the average age at index surgery was 75.9 years (range 35–94). The mean follow-up was 6.2 years (range 0.3–11). Results Twenty patients had a reoperation ; 10 for infection (four acute and six chronic joint infection) and 10 for cup failure (five fixation-failure, three aseptic loosening and two dislocation). Ten-year survivals for cup revision were 89% (CI, 83–94) and 92% (CI, 89–97) for all revision and revision for non-infectious reasons respectively. When solely evaluating for dislocation, the survival at 10 years was 99% (CI, 97–100). Considering primary and revision cases, ten-year survivals cup revision for aseptic reasons were 92.4% (CI, 84–100) and 92.5% (CI, 87–98) respectively. Conclusions The Lefevre retentive cup demonstrated excellent ten-year's survivorship. With the rate of aseptic loosening around 2% and a dislocation rate around 1%, the cup is as effective as other available devices and is therefore, a cost-effective tool to reduce the risk of dislocation in at-risk patients undergoing hip arthroplasty.

Retentive Cup Arthroplasty in Selected Hip Fracture Patients-A Prospective Series With a Minimum 3-Year Follow-Up.

Objective:To evaluate the efficacy of the use of retentive cup primary total hip replacement (THR) in high-dislocation risk subcapital fracture patients.Methods:During the years 2008 to 2012, 354 patients with displaced subcapital fracture were operated at our institute. The patients were selected to undergo primary constrained THR according to the following criteria: (1) a preinjury grade 4 or more on the Functional Independence Measure mobility item “5. Locomotion: walking/wheelchair” and grade 4 is defined as “4. Minimal assistance Requiring incidental hands-on help only” (patient performs >75% of the task) and (2) a disease leading to poor motor control. Exclusion criteria were normal muscular control and known infection of the involved joint.Results:Of the 354 patients, 87 fulfilled the inclusion criteria and underwent constrained total hip. Average age was 78 years with a female predominance (73%). Fifteen patients had prior hemiparesis, 19 had Parkinson disease, and 35 had generalized sarcopenia. Eighty-five patients had an uneventful recovery, with an average Hip Disability and Osteoarthritis Outcome Score (HOOS) of 76 ± 7 at 2 years. In 2 patients, the prostheses dislocated. In both cases, the dislocation was due to ring displacement and the inner head dislocated. One case was infected and the patient was treated by a Girdlestone procedure. In the other case, the prosthetic head was revised. The patient remained asymptomatic and at 4-year follow-up had an HOOS of 85.Discussion:It appears that constrained prosthesis is a suitable treatment for patients with poor muscular control having subcapital fractures. The functional results appear to be superior to those of bipolar arthroplasty and similar to the results of primary total hip arthroplasty while the dislocation risk is <3%.Conclusion:Semielective total hip arthroplasty using a retentive cup liner appears to offer good functional results with a low dislocation rate in patients with poor muscular control.

Short-term results with a constrained acetabular liner in patients at high risk of dislocation after primary total hip arthroplasty.

Dislocation following primary total hip arthroplasty (THA) is a complication with an incidence of 2%-5%. This study examines the clinical and radiological outcome of a constrained acetabular implant used in primary THA in high-risk patients to prevent dislocation. 54 patients with 55 constrained implants for primary THA were reviewed clinically and radiologically. Oxford, Harris Hip and Charlson scores were recorded. 54 patients, with an average age of 83.2 years, were followed up at a mean of 44.9 (20-74) months. 38 had an hydroxyapatite- (HA) coated acetabular shell with a constrained insert and 17 had a cemented constrained implant. The median Charlson score at surgery was 5 (4-10). There were significant improvements in Oxford, Harris hip pain and function scores and Charnley pain after surgery.2 patients had radiolucent lines on the most recent radiograph. Neither was symptomatic and the acetabular components had not migrated.3 patients developed postoperative infection, 1 deep requiring a 2-stage revision.Of the 29 patients who died, 1 required revision 2 months following surgery for dislocation of the constrained liner. This patient died 26 months later from unrelated causes having had no further complications from her surgery. There have been no further revisions or reoperations for dislocation in any of the other cases. The use of a constrained acetabular liner at primary THA in high risk patients for dislocation can successfully prevent this complication without increasing component loosening. In this series of 55 constrained implants we have a postoperative dislocation rate of 1.8%.

Freedom Constrained Liner for the Treatment and Prevention of Dislocation in Total Hip Arthroplasty.

Dislocation is one of the most common complications following total hip arthroplasty. The aim of our study was to assess failure rate of the Biomet Freedom constrained liner (Biomet, Warsaw, IN, USA) either in revision surgery for recurrent dislocation, or as a preventive method in high dislocation risk patients. We assessed retrospectively 105 consecutive surgical procedures in 103 patients where a Freedom constrained liner or cup was used in Turku University Hospital over a 7-year period from 2007 to 2014. The mechanical failure rate of the device was assessed based on medical records. The average age of the patients was 73.4 years. The number of male patients was 53 (51%). Mean follow-up time was 2.5 years. The association between failure of the device and potential risk factors-age, gender, indication, and approach-was analyzed with logistic regression. Results were expressed by odd ratios and 95% confidence intervals. The mechanical failure rate of the Freedom device was 6 out of 105 (5.7%). None of the 11 preventive primary THAs against dislocation failed, 4 out of 52 (7.7%) preventive revision THAs against dislocation failed, and 2 out of 42 (4.8%) of the treated dislocation cases failed. Four out of six failures were dislocations due to impingement and failure of the locking mechanism. Two liners failed because of loosening. The risk factors assessed were not associated with failure of the device. We found out that the mechanical failure rate of a Freedom constrained device was low. These results encourage us to continue using the device.

Dual-Mobility Articulations for Patients at High Risk for Dislocation

BackgroundThe purpose of this study was to evaluate the performance of dual-mobility articulations in patients at high risk for dislocation after revision total hip arthroplasty. MethodsWe reviewed the results of 36 consecutive revision total hip arthroplasties performed on patients considered high risk for instability. Indications for inclusion included abductor insufficiency, recurrent instability, failure of constrained liner, or inadequate intraoperative stability when trialing. ResultsAt a minimum of 2 years, there were 4 (11.1%) repeat revisions including both dual-mobility liners that were cemented into an acetabular shell and 2 for deep infection treated with a 2-stage exchange. There was one dislocation that was successfully closed reduced but no revisions for recurrent instability. The mean Harris hip score improved from 45 to 90 points (P < .001). ConclusionDual-mobility articulations are associated with a low rate of failure with no revisions for instability in this challenging group of patients.