Excellent Results of Large-Diameter Ceramic-on-Ceramic Bearings in Total Hip Arthroplasty at Minimum Ten-Year Follow-up.

AIMS: This study reports the minimum 10 year results of total hip arthroplasty (THA) performed using a monoblock acetabular component with a large-diameter head (LDH) ceramic-on-ceramic (CoC) bearing. METHODS: Of the 276 THAs included in this study, 237 (85%) were available for review at a mean of 10.5 years (range, 10 to 12) postoperatively. There were eleven deaths that occurred during the follow-up. Reoperations, implant revisions, adverse events, clinical outcomes, radiographic evaluation, and whole blood metal ion levels were assessed at the last follow-up. RESULTS: After a minimum of 10 years, implant survivorship was 98.7%. There were three revisions (1.3%): one for insufficient acetabular cup primary fixation, one traumatic periprosthetic acetabular fracture, and one probable deep chronic infection. No dislocation or ceramic implant fracture was observed. The mean University of California at Los Angeles (UCLA) activity score, Western Ontario and McMaster Universities Osteoarthritis Index score, and Forgotten Joint Score were 5.6 (2 to 10), 90.1 (9 to 100), and 79.2 (4 to 100), respectively. In the 10 years following implantation, at least 43% of patients reported hearing a squeaking noise from the prosthesis. All patients who had squeaking hips were satisfied with the surgery. The mean titanium level was 2.2 µg/L (1.1 to 5.6). No progressive radiolucent lines, osteolysis, or implant loosening signs were observed at the last radiographic evaluation. CONCLUSION: A LDH CoC THA provides outstanding long-term (minimum 10 year) implant survivorship with unrestricted activity while avoiding implant impingement, liner fracture, and hip instability. Functional outcomes, satisfaction, and joint perception were excellent. Although the incidence of squeaking was high, it did not affect patient satisfaction or function. The systemic titanium levels were low, related to unavoidable passive corrosion of implant surfaces, and did not reveal any indirect signs of trunnionosis.

Liner dissociation in a large-diameter ceramic-bearing acetabular component: a report of five cases.

BACKGROUND: Ceramic-on-ceramic (CoC) bearings for total hip arthroplasty (THA) have been offering very favorable results and survivorship since their introduction. In order to increase range of movement (ROM) and decrease dislocation rates, some manufacturers have introduced larger diameter head (LDH) CoC bearings. This has been achieved with the use of preassembled cup designs, in which the ceramic liner is already fitted into the metal backing and implanted as a monoblock component by the surgeon. In this report we present data from a series of 5 patients with ceramic liner dissociation from a monoblock cup. CASE PRESENTATION: All cases were overweight men with acetabular components of 56 or 58 mm. After a mean of 5.5 (range, 3.5-6.7) years, all patients reported sudden pain and audible noise when performing activities of daily living. Liner displacement was suspected on plain radiographs and confirmed by Ct-scan. Pneumarthrosis was present in all cases. Taper modular junction wear and corrosion signs were observed in the four revised patients. CONCLUSION: Although one of our case is still treated conservatively, implant revision is probably inevitable. Further LDH CoC implant design should take in consideration this potential complication by avoiding bearing diameters over 40mm and/or improving locking mechanism or by providing a real monoblock acetabular implant.

Despite higher revision rate, MoM large-head THA offers better clinical scores than HR: 14-year results from a randomized controlled trial involving 48 patients.

BACKGROUND: The high failure rates of metal on metal (MoM) large diameter head total hip arthroplasty (LDH THA) and hip resurfacing (HR) prevented their long-term comparisons with regards to clinical outcome. Such knowledge would be important as ceramic LDH bearing is now available. With long-term follow-up, we investigated the difference in 1) patient-reported outcome measures (PROMs); 2) revision and adverse events rates, and 3) metal ion levels between MoM LDH THA and HR. METHODS: Forty-eight patients were randomized for LDH THA (24) or HR (24) with the same MoM articulation. At a mean follow-up of 14 years, we compared between groups different PROMs, the number of revisions and adverse events, whole blood Cobalt (Co) and Chromium (Cr) ion levels, and radiographic signs of implant dysfunction. RESULTS: LDH THA (all cases: revised and well-functioning) had significantly better WOMAC (94 versus 85, p = 0.04), and more frequently reported having no limitation (p = 0.04). LDH THA revision rate was 20.8% (5/24) versus 8.3% (2/24) for HR (p = 0.4). Mean Co and Cr ion levels were higher in LDH THA compared to the HR (Co: 3.8 µg/L vs 1.7 µg/L; p = 0.04 and Cr: 1.9 µg/L vs 1.4 µg/L, p = 0.1). On radiographic analyses, 2 LDH THAs showed signs of adverse reaction to metal debris, whereas 1 loose femoral HR component was documented. CONCLUSION: In the long-term, MoM LDH THA had a high trunnion related revision rate but nonetheless showed better PROMs compared to HR. Provided with a well-functioning modular junction, non-MoM LDH THA would offer an appealing option. TRIAL REGISTRATION: ClinicalTrials.gov ( NCT04516239 ), August 18, 2020. Retrospectively registered.

The Impact of Mechanical and Restricted Kinematic Alignment on Knee Anatomy in Total Knee Arthroplasty.

BACKGROUND: Total knee arthroplasty (TKA), aiming at neutral mechanical alignment (MA), inevitably modifies the patient's native knee anatomy. Another option is kinematic alignment (KA), which aims to restore the original anatomy of the knee. The aim of this study was to evaluate the variations in lower limb anatomy of a patient population scheduled for TKA, and to assess the use of a restricted KA TKA protocol and compare the resulting anatomic modifications with the standard MA technique. METHODS: A total of 4884 knee computed tomography scans were analyzed from a database of patients undergoing TKA with patient-specific instrumentation. The lateral distal femoral angle (LDFA), medial proximal tibial angle (MPTA), and hip-knee-ankle angle (HKA) were measured. Bone resections were compared using a standard MA and a restricted KA aiming for independent tibial and femoral cuts of maximum ±5° deviation from the coronal mechanical axis and a resulting overall coronal HKA within ±3° of neutral. RESULTS: The mean preoperative MPTA was 2.9° varus, LDFA was 2.7° valgus, and overall HKA was 0.1° varus. Using our protocol, 2475 knees (51%) could have undergone KA without adjustment. To include 4062 cases (83%), mean corrections of 0.5° for MPTA and 0.3° for LDFA were needed, significantly less than with MA (3.3° for MPTA and 3.2° for LDFA; P < .001). CONCLUSION: The range of knee anatomy in patients scheduled for TKA is wide. MA leads to greater modifications of knee joint anatomy. To avoid reproducing extreme anatomy, the proposed restricted KA protocol provides an interesting hybrid option between MA and true KA.

Functional joint line obliquity after kinematic total knee arthroplasty.

PURPOSE: Kinematic total knee arthroplasty (TKA) is an emerging technique, but concerns remain around the effect of implanting the prosthesis in more anatomic orientations. Native knees show variation in joint line orientation relative to the tibial mechanical axis but the joint line remains parallel to the floor when standing. This study was undertaken to evaluate joint line obliquity relative to the floor when weight-bearing after kinematic TKA to see if a similar effect occurs. METHODS: Preoperative and postoperative measurements were taken for 55 consecutive kinematically aligned TKAs, including the joint line orientation angle (JLOA), formed between the joint line and a line parallel to the floor. RESULTS: The mean medial proximal tibial angle (MPTA) was 3.4° varus pre-operatively (1.7° valgus to 7.9° varus, SD 2.0), and 3.0° varus postoperatively (5.5° valgus to 6.5° varus, SD 2.1). The mean postoperative JLOA was 1.0° varus with a smaller range than the MPTA (2.6° valgus to 6° varus, SD 1.9). The difference between these two measurements was significant (mean 2°, SD 2.5, p < 0.001). CONCLUSIONS: Relative to the mechanical axis, 33 tibial components would be considered at risk outliers, being orientated at more than 3° in varus or valgus. However, only six components were outside this range relative to the vertical, all in varus (mean 4.2°). This latter measurement may better represent how the prosthesis is functionally loaded and is similar to mechanically aligned TKAs with good survivorship. This may help explain why kinematic alignment does not lead to higher earlier failure rates that may result if similar orientations were seen with mechanically aligned TKA.

Tibia valga morphology in osteoarthritic knees: importance of preoperative full limb radiographs in total knee arthroplasty.

Osteoarthritis of the knee is associated with deformities of the lower limb. Tibia valga is a contributing factor to lower limb alignment in valgus knees. We evaluated 97 valgus knees and 100 varus knees. Long-leg films were taken in weight bearing with both knees in full extension. For valgus knees, 52 knees (53%) had a tibia valga deformity. Average tibia valgus deformation was 5.0°. For varus knees, there was only 1 case of tibia valga (1%), with a deformation of 2.5°. The aim of this study was to assess the prevalence of primary tibia valga in valgus and varus knees and understand how it affects our approach to total knee arthroplasty (TKA). We recommend having full-leg length films when planning for TKA in valgus knees.

Whole blood metal ion measurement reproducibility between different laboratories.

Monitoring patients' metal ion blood concentrations can be useful in cases of problematic metal on metal hip implants. Our objective was to evaluate the reproducibility of metal ion level values measured by two different laboratories. Whole blood samples were collected in 46 patients with metal on metal hip arthroplasty. For each patients, two whole blood samples were collected and analyzed by two laboratories. Laboratory 1 had higher results than laboratory 2. There was a clinically significant absolute difference between the two laboratories, above the predetermined threshold, 35% of Cr samples and 38% of Co samples. All laboratories do not use the same technologies for their measurements. Therefore, decision to revise a metal on metal hip arthroplasty should rely on metal ion trends and have to be done in the same laboratory.

Periarticular injection in knee arthroplasty improves quadriceps function.

BACKGROUND: The postoperative analgesic potential of periarticular anesthetic infiltration (PAI) after TKA is unclear as are the complications of continuous femoral nerve block on quadriceps function. QUESTIONS/PURPOSES: We asked (1) whether PAI provides equal or improved postoperative pain control in comparison to a femoral nerve block in patients who have undergone TKA; and (2) if so, whether PAI improves early postoperative quadriceps control and facilitates rehabilitation. METHODS: We randomized 60 patients to receive either PAI or femoral nerve block. During the first 5 days after TKA, we compared narcotic consumption, pain control, quadriceps function, walking distance, knee ROM, capacity to perform a straight leg raise, and active knee extension. Medication-related side effects, complications, operating room time, and hospitalization duration were compared. RESULTS: Opioid consumption was lower in the PAI group during the first 8 postoperative hours (12.5 mg versus 18.7 mg morphine), as was reported pain at rest (1.7 versus 3.5 on a 10-point VAS). Thereafter, narcotic consumption and reported pain were similar up to 120 hours. More subjects in the femoral nerve block group experienced quadriceps motor block (37% versus 0% in the PAI group). On Days 1 to 3, subjects in the PAI group experienced better capacity to perform the straight leg raise, active knee extension, and had longer walking distances. CONCLUSIONS: PAI provided pain control equivalent to that of a femoral nerve block while avoiding a motor block and its negative functional impacts. The data suggest it should be considered an alternative to a femoral nerve block. LEVEL OF EVIDENCE: Level I, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

A new interface element with progressive damage and osseointegration for modeling of interfaces in hip resurfacing.

Finite element models of orthopedic implants such as hip resurfacing femoral components usually rely on contact elements to model the load-bearing interfaces that connect bone, cement and implant. However, contact elements cannot simulate progressive degradation of bone-cement interfaces or osseointegration. A new interface element is developed to alleviate these shortcomings. This element is capable of simulating the nonlinear progression of bone-cement interface debonding or bone-implant interface osseointegration, based on mechanical stimuli in normal and tangential directions. The new element is applied to a hip resurfacing femoral component with a stem made of a novel biomimetic composite material. Three load cases are applied sequentially to simulate the 6-month period required for osseointegration of the stem. The effect of interdigitation depth of the bone-cement interface is found to be negligible, with only minor variations of micromotions. Numerical results show that the biomimetic stem progressively osseointegrates (alpha averages 0.7 on the stem surface, with spot-welds) and that bone-stem micromotions decrease below 10 microm. Osseointegration also changes the load path within the femoral bone: a decrease of 300 microepsilon was observed in the femoral head, and the inferomedial part of the femoral neck showed a slight increase of 165 microepsilon. There was also increased stress in the implant stem (from 7 to 11 MPa after osseointegration), indicating that part of the load is supported through the stem. The use of the new osseointegratable interface element has shown the osseointegration potential of the biomimetic stem. Its ability to model partially osseointegrated interfaces based on the mechanical conditions at the interface means that the new element could be used to study load transfer and osseointegration patterns on other models of uncemented hip resurfacing femoral components.

Assessing and monitoring agroenvironmental determinants of recreational freshwater quality using remote sensing.

Diverse fecal and nonfecal bacterial contamination and nutrient sources (e.g. agriculture, human activities and wildlife) represent a considerable non-point source load entering natural recreational waters which may adversely affect water quality. Monitoring of natural recreational water microbial quality is most often based mainly on testing a set of microbiological indicators. The cost and labour involved in testing numerous water samples may be significant when a large number of sites must be monitored repetitively over time. In addition to water testing, ongoing monitoring of key environmental factors known to influence microbial contamination may be carried out as an additional component. Monitoring of environmental factors can now be performed using remote sensing technology which represents an increasingly recognized source of rigorous and recurrent data, especially when monitoring over a large or difficult to access territory is needed. To determine whether this technology could be useful in the context of recreational water monitoring, we evaluated a set of agroenvironmental determinants associated with fecal contamination of recreational waters through a multivariable logistic regression model built with data extracted from satellite imagery. We found that variables describing the proportions of land with agricultural and impervious surfaces, as derived from remote sensing observations, were statistically associated (odds ratio, OR = 11 and 5.2, respectively) with a higher level of fecal coliforms in lake waters in the southwestern region of Quebec, Canada. From a technical perspective, remote sensing may provide important added-value in the monitoring of microbial risk from recreational waters and further applications of this technology should be investigated to support public health risk assessments and environmental monitoring programs relating to water quality.

Alumina on alumina versus metal on conventional polyethylene: a randomized clinical trial with 9 to 15 years follow-up.

We report the long-term results of a randomized clinical trial that compares, in total hip arthroplasty in a young population, metal-on-conventional polyethylene and alumina-on-alumina ceramic bearings. One hundred and forty hips in 116 patients were randomized. Re-operation, revision rate, clinical scores, and radiological signs of osteolysis and loosening were compared at average follow-up of 123 (9-15) years. At final FU, 107 hips were available for clinical evaluation. Eight (11.6%) revisions were performed in the polyethylene group versus 1 (1.4%) in the ceramic group (p = 0.017). All revisions in the polyethylene group were related to bearing wear: 4 for aseptic loosening with severe osteolysis, 1 for polyethylene induced compressive granulomatous tumor, and 3 for severe liner wear. The only revised case from the ceramic group was secondary to mechanical stem loosening. Mean annual polyethylene wear was 0.19mm/year; wear was not measurable in the ceramic group. Our study confirms, in the long-term, the superiority of ceramic-on-ceramic pairing in comparison to metal-on-conventional polyethylene and supports their use in young, active patients.

A hydrological modeling framework for defining achievable performance standards for pesticides.

This paper proposes a hydrological modeling framework to define achievable performance standards (APSs) for pesticides that could be attained after implementation of recommended management actions, agricultural practices, and available technologies (i.e., beneficial management practices [BMPs]). An integrated hydrological modeling system, Gestion Intégrée des Bassins versants à l'aide d'un Système Informatisé, was used to quantify APSs for six Canadian watersheds for eight pesticides: atrazine, carbofuran, dicamba, glyphosate, MCPB, MCPA, metolachlor, and 2,4-D. Outputs from simulation runs to predict pesticide concentration under current conditions and in response to implementation of two types of beneficial management practices (reduced pesticide application rate and 1- to 10-m-wide edge-of-field and/or riparian buffer strips, implemented singly or in combination) showed that APS values for scenarios with BMPs were less than those for current conditions. Moreover, APS values at the outlet of watersheds were usually less than ecological thresholds of good condition, when available. Upstream river reaches were at greater risk of having concentrations above a given ecological thresholds because of limited stream flows and overland loads of pesticides. Our integrated approach of "hydrological modeling-APS estimation-ecotoxicological significance" provides the most effective interpretation possible, for management and education purposes, of the potential biological impact of predicted pesticide concentrations in rivers.

Periprosthetic joint infections at a teaching hospital in 1990-2007.

BACKGROUND: Periprosthetic joint infections (PJIs) are major complications associated with high costs and substantial morbidity. We sought to evaluate hip and knee arthroplasty infection rates at our hospital, compare them in periods before and after implementation of measures to reduce PJIs (1990-2002 and 2003-2007) and identify associated risk factors. METHODS: We retrospectively reviewed records of patients who received primary hip or knee total joint prostheses at our centre between Jan. 1, 1990, and Dec. 31, 2007, and were readmitted for the treatment of infection related to their surgery. We also reviewed data from a prospective surveillance protocol of total hip (THA) and knee arthroplasty (TKA) infections that started in November 2005. We ascertained the annual rates of deep, superficial and hematogenous infections. RESULTS: During the periods studied, 2403 THAs and 1220 TKAs were performed. For THA, the average rates of deep, superficial and hematogenous infections were 2.0%, 0.8% and 0.3%, respectively. For TKA, the rates were 1.6%, 0.7% and 0.2%, respectively. Of 106 infected joints, 84 (79.2%) presented risk factors for infection. Efforts to reduce the infection rate at our institution began in 2003. We achieved a 44% decrease in the deep infection rate for THA (2.5% v. 1.4%; p = 0.06) and a 45% decrease for TKA (2.0% v. 1.1%, p = 0.20) between the periods studied. CONCLUSION: Knowing the actual infection rate associated with different procedures in specific settings is essential to identify unexpected problems and seek solutions to improve patient care. Although we do not know what specific improvements were successful, we were able to decrease our infection rates to levels comparable to those reported by similar care centres.

Hypesthesia after anterolateral versus midline skin incision in TKA: a randomized study.

BACKGROUND: The anterior midline skin incision in a TKA provides excellent surgical exposure. However, it usually requires sectioning the infrapatellar branch of the saphenous nerve which may be associated with lateral cutaneous hypesthesia and neuroma formation. QUESTIONS/PURPOSES: We asked whether an anterolateral skin incision to the knee would decrease the area of skin hypesthesia and associated postoperative discomfort. PATIENTS AND METHODS: We randomized 69 knees to receive a TKA through either a midline or an anterolateral skin incision. We assessed skin sensitivity by application of the Semmes-Weinstein monofilament at 13 reference points at 6 weeks and 6 and 12 months postoperatively. The area of hypesthesia was measured using Mesurim Pro 9(®) software. Patient knee ROM, Knee Injury and Osteoarthritis Outcome Score (KOOS), and WOMAC clinical score also were assessed. RESULTS: The area of hypesthesia was less after an anterolateral compared with a midline incision up to 1 year after surgery: the areas of hypesthesia were, respectively, 32 cm(2) versus 76 cm(2) at 6 weeks, 14 cm(2) versus 29 cm(2) at 6 months, and 7 cm(2) versus 19 cm(2) at 1 year. Clinical scores and knee ROM were similar in both groups at each followup. At 1 year, in the entire group we observed a correlation between a smaller area of paresthesia and better WOMAC and KOOS scores and greater knee flexion. CONCLUSIONS: Compared with the midline skin incision, the anterolateral incision is associated with fewer sensory disturbances and appears to be a reasonable alternative in TKA. LEVEL OF EVIDENCE: Level I, therapeutic study. See the guidelines for authors for a complete description of levels of evidence.

Metal Ion release with large-diameter metal-on-metal hip arthroplasty.

Preoperative and postoperative ion concentrations were measured in 29 metal-on-metal, large-diameter head total hip arthroplasty (LDH-THA) patients. Mean chromium, cobalt (Co), and titanium levels from LDH-THA were 1.3, 2.2, and 2.7 µg/L at 12 months. The open femoral head design showed significantly higher Co concentrations than the closed design (3.0 vs 1.8 µg/L, P = .037). Compared with previously published ion levels from a hip resurfacing system presenting the same bearing characteristics, Co levels were significantly higher in LDH-THA (2.2 vs 0.7 µg/L, P < .001). This study has demonstrated that the addition of a sleeve with modular junctions and an open femoral head design of LDH-THA causes more Co release than bearing surface wear (157% and 67%, respectively). Even if no pathologic metal ion threshold level has been determined, efforts should be made to minimize its release. We recommend modification or abandonment of the modular junction and femoral head open design for this specific LDH-THA system.

No radiological and biological sign of trunnionosis with Large Diameter Head Ceramic Bearing Total Hip Arthroplasty after 5 years.

BACKGROUND: Trunnionosis of large diameter (LDH) metal-on-metal total hip arthroplasty (THA) was linked to high systemic chromium (Cr) and cobalt (Co) ion levels and local adverse reactions to metal debris (ARMD). The safety of CoC LDH THA is not yet available at mid-term. Measuring whole blood Ti level of ceramic on ceramic (CoC) LDH THA with a titanium (Ti) stem is an indirect way to assess the performance of its head-neck taper modular junction. Therefore, we wanted to determine: (1) if the whole blood Ti ion levels in patients with LDH CoC THA after a minimum of 5 years of implantation is within the expected values for similar well performing Ti THA, (2) if Ti level scientifically increases over time, which would suggest the presence of a progressive modular head/neck junction wear process, (3) if clinical or radiographical manifestations of implant dysfunction are present? HYPOTHESIS: Ti blood levels of LDH CoC THA will indirectly reflect the expected levels due to passive corrosion of the implants and will be stable over time. PATIENTS AND METHODS: We report the whole blood Ti, Cr, and Co levels at 5years minimum for 57 patients with unilateral primary LDH CoC THA with head sizes ranging from 36 to 48mm using Ti stem and acetabular component. To compare Ti ion levels modification over time, in 25 patients were a previous measurement (1-3years) was available, we compared it to their last follow-up results (>5 years). Mean Ti level in well performing Ti THAs is recognized to be around 2.0 ug/L. Although, there are no universally accepted Ti levels associated with problematic implant, we used safety threshold of 10 ug/L. Clinical and radiological outcomes were recorded at last follow-up. RESULTS: At 79 months mean follow-up, all mean Ti levels were 1.9µg/L (min 1.2, max 4.4) and all subject had values below the safety threshold of 10ug/L. In the subgroup of 25 cases with a previous measurement, there was a decrease in mean Ti levels between 20 months and 78 months follow-up (2.2µg/L (1.6-3.9) versus 2.0µg/L (1.4-2.8), p=0.007). No statistically significant relation was observed between Ti level at last FU and bearing diameter (rho=0.046, p=0.0734) or the presence or absence of a Ti adaptor sleeve (p=0.454): 1.94ug/L (min 1.20, max 2.80) versus 1.90ug/L (min 1.20, max 4.40). At last follow up, no patients presented osteolysis signs on radiographs, clinical signs of ARMD or were reoperated. Most patients had excellent clinical with 98% of them reporting minor (29%) or no functional limitation (69%) and 44% perceive their THA as a natural hip joint. However, 3/57patients (5%) temporarily experienced hip squeaking and 18/57 (31%) reported clicking sound. CONCLUSION: With the tested LDH CoC THA, Ti levels were low and related the uneventful and unavoidable passive corrosion of implant surfaces. Mid-term measurement of Ti in subjects with LDH CoC did not reveal any indirect signs of trunnionosis, which should already be observable by this time. LEVEL OF EVIDENCE: IV, retrospective study.

Mid-term results of total hip arthroplasty using a novel uncemented short femoral stem with metaphyso-diaphyseal fixation.

PURPOSE: Short stems were developed with the promise of providing easier implantation, facilitating revision, reducing thigh pain and proximal stress shielding. The aim of this study is to present the mid-term clinical results of a titanium short stem with modular neck. METHODS: This is a prospective case series of 144 THAs performed on a series of 131 patients using the PROFEMUR Preserve Femoral Stem (MicroPort Orthopedics, Arlington, TN, USA). 2 surgeons, operated on the patients using a mini-posterior approach. The primary outcomes evaluated were stem revision for aseptic loosening and all-cause stem revision. Clinical and radiographic outcomes were also assessed. RESULTS: Of the 144 THAs, there were 43 males and 101 females, with an average age of 61 (range 22-92) years at surgery. After a mean of 78 (range 53-87) months follow-up, there were 2 (1.5%) femoral implant revisions; 1 for early femoral periprosthetic fracture and 1 for fatigue failure of the modular femoral neck. There were no cases of stem aseptic loosening and radiographic analysis demonstrated no cases of stem migration. The mean UCLA activity, WOMAC and Fogotten Joint scores were respectively 6.1, 10.7 and 86.6. 70% of prosthetic hips were observed as having no restriction and 99.2% of patients were satisfied with their THA. CONCLUSIONS: This short modular stem produced satisfactory clinical and radiological results at mid-term, with 98.5% implant survival for any cause of stem revision and no revisions for aseptic loosening. Long-term results are required to further evaluate the stem's promising early results.

The John Charnley Award: The functional outcome of hip resurfacing and large-head THA is the same: a randomized, double-blind study.

UNLABELLED: Better functional outcome is believed by some to occur after hip resurfacing (HR) than conventional 28-mm total hip arthroplasty (THA) in young and active patients with hip osteoarthritis. However, the postulated superior outcome of HR over THA may simply be the result of a bias in patient selection or the use of a larger femoral head. We therefore asked whether HR would demonstrate superior functional outcome when compared with a THA with a large-diameter femoral head in a randomized, double-blind study. Gait speed and postural balance evaluations, functional tests, and clinical data were analyzed preoperatively and at 3, 6, and 12 months after surgery. Gait speed was used as the primary outcome measure. Forty-eight patients were randomized in the study and a third group of 14 healthy subjects served as controls. The gait speed and postural balance evaluations, the performance at most functional tests, and clinical scores were similar in HR and large-head THA groups at each followup period. The operated patients reached most control group values at 3 months postoperatively. By these measures, HR did not provide better clinical function over large-head THA. LEVEL OF EVIDENCE: Level I, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Hip Resurfacing Compared with 28-mm Metal-on-Metal Total Hip Replacement: A Randomized Study with 15 Years of Follow-up.

BACKGROUND: Bone stock conservation, hip anatomy preservation, and greater stability are among the promoted advantages of hip resurfacing (HR). However, the disappointing failure of some implants nearly led to its abandonment. The aim of this study was to compare clinical scores and revision and complication rates after HR with those after total hip arthroplasty (THA). METHODS: Two hundred and three hips were randomized to 28-mm metal-on-metal (MoM) THA (99 hips) or to HR (104 hips). Main outcome measures compared between groups were the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score, the revision rate, and the complication rates. The radiographic findings were also assessed. RESULTS: After a mean follow-up of 15 years (range, 14 to 16 years), 9 (4.4%) of the 203 patients were lost to follow-up and 15 (7.4%) had died. The Kaplan-Meier survivorship, with revision for any reason as the end point, was 89.2% (95% confidence interval [CI], 82.3% to 96.1%) for HR and 94.2% (95% CI, 89.3% to 99.1%) for THA (p = 0.292). The reasons for revision included infection (3 patients), recurrent dislocation (1 patient), and adverse reaction to metal debris (ARMD) (1 patient) in the THA group and ARMD (2 patients) and femoral head loosening (7 patients) in the HR group. With aseptic revision as the end point, the Kaplan-Meier survivorship was significantly higher in the THA group (97.4% versus 89.2%; p = 0.033). No dislocation occurred in the HR group compared with 4 in the THA group (p = 0.058). Both groups achieved a similar mean WOMAC score (10.7 in the HR group and 8.8 in the THA group; p = 0.749), Forgotten Joint Score (87.1 and 85.3, respectively; p = 0.410), University of California Los Angeles (UCLA) activity score (6.3 and 6.4, respectively; p = 0.189), and overall joint perception (p = 0.251). CONCLUSIONS: The specific HR and MoM 28-mm THA implants used in this study showed good long-term survival and function. The overall rates of complications and revisions were similar in both groups but were of different types. As it provides better femoral bone preservation and biomechanical reconstruction, HR may continue to have a role in selected patients when performed by experienced surgeons and using validated implants. LEVEL OF EVIDENCE: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Large head ceramic-on-ceramic bearing in primary total hip arthroplasty: average 3-year follow-up of a multicentre study.

BACKGROUND: Surgeons are increasingly using larger femoral head sizes in total hip arthroplasty (THA) to improve stability and reduce the rate of dislocation, 1 of the leading causes of revision surgery. Large ceramic head sizes up to 48 mm can now be used with monoblock acetabular components. National registries have shown promising results at short-term with large diameter ceramic-on-ceramic THA, with very low revision rates.This study reports on the average 3-year follow up of a press-fit monoblock large diameter acetabular shell with a pre-assembled ceramic liner, with emphasis on the radiographic outcome, complications related to the implantation of the cup, and the patient's clinical outcome. METHODS: 170 hips in 169 patients were reviewed at an average 38 ± 5.8 months following surgery. RESULTS: The radiographic review revealed no acetabular cup loosening, no osteolysis and no cup migration. 1 acetabular cup was revised for malposition. The patient clinical outcome and the satisfaction rate were excellent. At 3 years, 7.1% of patients complained of groin pain and 3.5% spontaneously reported hip joint generated noise. 1 patient sustained a non-recurrent traumatic hip dislocation 2 years post surgery. CONCLUSIONS: New technology should be introduced cautiously on the market. This is especially true for the large diameter ceramic monoblock acetabular component used in this study since it involves a new acetabular component design. At short term, we have not identified new modes of failure with this implant. Longer follow-up is still needed to assess the safety of large ceramic bearing in THA.