Calcar Resorption Research Articles

Early radiographic and clinical outcomes of primary short stem anatomic total shoulder arthroplasty with a peripherally enhanced fixation glenoid: a multicenter study

BackgroundGlenoid component loosening remains the most common reason for revision of anatomic total shoulder arthroplasty (aTSA). We assessed early clinical and radiographic outcomes following aTSA using a press-fit short stem and a peripherally enhanced fixation glenoid. Methods275 consecutive patients with end-stage glenohumeral arthritis and Walch A- or B-type glenoid morphology who underwent primary aTSA in 2017-2018 at two high-volume shoulder arthroplasty institutions were evaluated, and patient-reported outcomes (PROMs) and radiographic findings were studied in those with completed baseline and minimum 2-year follow-up, respectively. Patient demographics, glenoid morphology, body mass index (BMI), Charlson Comorbidity Index (CCI), range of motion, American Shoulder and Elbow Surgeons (ASES) score, and Simple Assessment Numeric Evaluation score were collected. Radiographic analysis of glenoid and humeral components was performed. Multivariable logistic, equal adjacent odds ordinal, and beta regression were respectively used to identify predictors of glenoid radiolucent lines, humeral calcar resorption, and total ASES score. ResultsPatients were 43% female, with a mean age of 66, a median BMI of 30, and median follow-up of 28.4 months. ASES and Simple Assessment Numeric Evaluation scores improved by respective medians of 54.4 and 55.0 points, forward elevation by median 35°, and external rotation by median 30° (all P < .001 for preoperative to postoperative change). Postoperative radiographs of 177 cases showed 10 (5.7%) glenoid osteolysis, 51 (28.8%) glenoid radiolucent lines, and 81 (45.8%) calcar resorptions. The follow-up duration (median 40.1 vs. 27.2 months; P < .001), BMI (median 27.5 vs. 30.7; P < .001), and Charlson Comorbidity Index (Q3 0 vs. 1; P = .02) were associated with glenoid osteolysis in bivariate analyses. In multiple logistic regression, surgeon (C vs. A/B) was the only statistically significant predictor of glenoid radiolucent lines [OR 0.27, 95% CI (0.1, 0.8)]. By descending importance, Surgeon C [OR 6.5 (2.0, 20.5)], humeral canal filling ratio [upper vs. lower quartile OR 2.3 (1.3, 4.0)], mediolateral humeral head deviation [upper vs. lower quartile OR 1.9 (1.0, 3.5)], and glenoid osteolysis [OR 13.5 (2.6, 71.6)] significantly predicted greater calcar resorption. Longer follow-up duration marginally statistically significantly predicted lower ASES score [upper vs. lower quartile OR 0.8 (0.6, 1.0)]. ConclusionsFollowing aTSA with a peripherally enhanced fixation glenoid, pain, range of motion, and patient-reported outcomes significantly improved at a minimum of 2 years with only 5.7% glenoid osteolysis despite heterogeneous preoperative glenoid pathologies.

Prospective evaluation of clinical and radiographic 10-year results of Fitmore short-stem total hip arthroplasty

BackgroundShort stems were introduced into total hip arthroplasty (THA) to preserve bone stock, to transmit more load to the proximal femur, and to enable minimal invasive approaches. This study is the first long-term study (with a follow-up of 10 years) of the survival as well as the clinical and radiographic outcomes of the Fitmore hip stem, a short curved uncemented stem.MethodsIn total, 123 Fitmore hip stems were prospectively evaluated. At the final 10-year follow-up, 80 Fitmore stems (78 patients: 30 female, 48 male) were eligible for evaluation. Clinical parameters were thigh pain, EQ-5D, Harris Hip Score (HHS) and Oxford Hip Score. Radiographic parameters were cortical hypertrophy (CH), bone condensation, cortical thinning, radiolucency, reactive lines, calcar rounding, calcar resorption, subsidence and varus/valgus position.ResultsAfter 10 years, there was a survival rate of 99% (1 revision because of aseptic stem loosening). HHS had improved from 59 to 94 and Oxford Hip Score from 22 to 43. CH rate after 1 year was 69% and after 10 years 74%. In the first year, radiolucency was found in 58% and in 17.5% after 10 years. Subsidence after 1 year was 1.6 ± 1.6 mm and 5.0 ± 3.1 mm after 10 years.ConclusionsThe Fitmore hip stem showed a survival rate of 99% as well as good clinical and radiographic outcomes in the long-term follow-up of 10 years.

Impact of humeral stem length on calcar resorption in anatomic total shoulder arthroplasty

Use of standard-length anatomic total shoulder (TSA) humeral stems has been associated with high rates of medial calcar bone loss. Calcar bone loss has been attributed to stress shielding, debris-induced osteolysis, and undiagnosed infection. Short stem and canal-sparing humeral components may provide more optimal stress distribution and thus lower rates of calcar bone loss related to stress shielding. The purpose of this study is to determine whether implant length will affect the rate and severity of medial calcar resorption. A retrospective review was performed on TSA patients treated with three different-length humeral implants (canal-sparing, short, and standard-length designs). Patients were matched 1:1:1 based on both gender and age (±4 years), resulting in 40 patients per cohort. Radiographic changes in medial calcar bone were evaluated and graded on a 4-point scale, from the initial postoperative radiographs to those at 3 months, 6 months, and 12 months. The presence of any degree of medial calcar resorption demonstrated an overall rate of 73.3% at one year. At 3 months, calcar resorption was observed in 20% of the canal-sparing cohort, while the short and standard designs demonstrated resorption in 55% and 52.5%, respectively (P=.002). At 12 months, calcar resorption was seen in 65% of the canal-sparing design, while both the short and standard designs had a 77.5% rate of resorption (P=.345). The severity of calcar resorption for the canal-sparing cohort was significantly lower at all time points when compared to the short stem (3 months, P=.004; 6 months, P=.003; 12 months, P=.004) and at 3 months when compared to the standard-length stem (P=.009). Patients treated with canal-sparing TSA humeral components have significantly lower rates of early calcar resorption with less severe bone loss when compared to patients treated using short and standard-length designs.

Onlay versus inlay reverse total shoulder arthroplasty: a retrospective comparison of radiographic and clinical outcomes

IntroductionRecent innovations in reverse shoulder arthroplasty (RSA) have presented 2 distinct humeral stem designs: an onlay system that rests above the anatomic neck and an inlay component that rests within the metaphysis. The purpose of this study is to compare clinical and radiographic outcomes between inlay and onlay-designed humeral stems in lateral center of rotation RSA implant systems. MethodsA retrospective cohort study was performed on primary RSA patients treated by 2 surgeons at 2 separate hospitals with a minimum 2-year follow-up. Patients were categorized based on treatment with an onlay or inlay humeral design and matched 1:1 by indication and age. Patient-reported outcome measures (PROMs), including the Simple Shoulder Test, American Shoulder and Elbow Surgeons, and Visual Analog Score for pain, as well as active motion (forward elevation, internal rotation) were recorded at pre- and postoperative intervals. An Inlay-Onlay index assessed the degree of inset or offset of each particular implant referencing the anatomic neck. Radiographic analysis focused on scapular notching, bone resorption around the humeral stem, and acromion stress fractures. ResultsA total of 92 patients participated in the 1:1 matched analysis (46 each group). Cohorts were similar in age, gender, indication, follow-up length, and preoperative PROMs, with the exception of Simple Shoulder Test. At the most recent follow-up, there were no differences in all PROMs between groups. There were no differences in active internal rotation, but patients with an onlay-configuration demonstrated greater external rotation (P< .001) and forward flexion (P< .001). Greater tuberosity and calcar resorption occurred in 34 (74%) and 18 (39%) patients with an onlay-designed prosthesis, compared to 13 (28%) and 1 (2%) in the inlay group, respectively (P< .0001). Both groups had low rates of scapular notching (P= 1.0), while acromial fractures occurred in 6 patients with an onlay stem and in 4 patients with the inlay stem (P= .73). ConclusionThere were no differences in clinical outcomes or incidence of acromial fractures following RSA with an onlay- or inlay-style humeral stem prosthesis. Bone resorption of the proximal humerus occurred more frequently in patients with an onlay prosthesis, suggesting that an inlay prosthesis may afford better prevention of humeral stress shielding. Level Of EvidenceLevel III; Retrospective Comparative Study

Medial calcar bone resorption after anatomic total shoulder arthroplasty: does it affect outcomes?

The incidence of medial calcar resorption has been shown to be common after uncemented total shoulder arthroplasty (TSA). With etiologies including stress shielding, debris-induced osteolysis, and infection, the clinical impact of medial calcar resorption has not been specifically examined. The purpose of this study was to determine whether resorption is associated with inferior outcomes or higher rates of radiographic loosening in TSA patients. We conducted a retrospective review of TSA patients with minimum 2-year clinical follow-up. Patient-reported and functional outcome measures were recorded preoperatively and postoperatively. Postoperative radiographs were evaluated for glenoid and humeral component loosening. A new calcar resorption grading system was introduced to quantify the degree of resorption and assess the progression. A total of 171 patients met the inclusion criteria, with average clinical and radiographic follow-up periods of 50 and 46 months, respectively. Calcar resorption was identified in 110 patients (64.3%). No significant overall differences were observed between the patients with and without calcar resorption. Subgroup analysis showed that patients with grade 3 resorption had a higher incidence of glenoid radiolucencies (50%, P = .001) and patients with a progression from grade 1 to grade 3 had higher incidences of glenoid (50%, P = .003) and humeral (9%, P = .039) radiolucencies. Medial calcar resorption following TSA with a standard-length press-fit humeral component is common. Overall, no differences in patient-reported outcome measures or radiographic loosening were found compared with patients without calcar resorption. However, grade 3 calcar resorption and more dramatic progression of resorption should raise the suspicion of prosthetic loosening.

Outcomes of anatomic total shoulder arthroplasty in patients with excessive glenoid retroversion: a case-control study

Ideal management of severe glenoid retroversion during anatomic total shoulder arthroplasty (TSA) remains controversial, as previous reports have suggested that severe retroversion may negatively impact clinical outcomes. The purpose of this study was to evaluate the impact of severe glenoid retroversion on clinical and radiographic TSA outcomes using a standard glenoid component, as well as to compare outcomes amongpatients with less severe retroversion. A case-control study was performed comparing 40 patients treated with TSA with more than 20° of glenoid retroversion preoperatively (average follow-up, 53 months) vs. a matched cohort of 80 patients with less than 20° of retroversion (average follow-up, 49 months). In all patients, the surgical technique, implant design, and postoperative rehabilitation protocol were identical. Patients were matched based on sex, age, indication, and prosthetic size. Comparisons were made regarding patient-reported outcome measures (PROMs), motion, postoperative radiographic loosening, and the presence of medial calcar resorption. Preoperatively, both groups demonstrated similar PROMs and measured motion, except for preoperative Single Assessment Numeric Evaluation scores and American Shoulder and Elbow Surgeons total scores, which were higher for the severe retroversion group (44.4 vs. 31.3 [P = .012] and 34.9 vs. 29.4 [P = .048], respectively). Postoperative PROMs and motion were also similar between the 2 cohorts. No significant differences were observed for postoperative radiographic findings. Medial calcar resorption was identified in 74 patients (61.7%). Calcar resorption and individual resorption grades were not found to differ significantly. At midterm follow-up, preoperative severe glenoid retroversion does not appear to influence clinical or radiographic outcomes of TSA using a standard glenoid component.

Mid-term radiological results of a cementless short humeral component in anatomical and reverse shoulder arthroplasty.

Shoulder arthroplasty using short humeral components is becoming increasingly popular. Some such components have been associated with relatively high rates of adverse radiological findings. The aim of this retrospective review was to evaluate the radiological humeral bone changes and mechanical failure rates with implantation of a short cementless humeral component in anatomical (TSA) and reverse shoulder arthroplasty (RSA). A total of 100 shoulder arthroplasties (35 TSA and 65 RSA) were evaluated at a mean of 3.8 years (3 to 8.3). The mean age at the time of surgery was 68 years (31 to 90). The mean body mass index was 32.7 kg/m2 (17.3 to 66.4). Greater tuberosity stress shielding was noted in 14 shoulders (two TSA and 12 RSA) and was graded as mild in nine, moderate in two, and severe in three. Medial calcar resorption was noted in 23 shoulders (seven TSA and 16 RSA), and was graded as mild in 21 and moderate in two. No humeral components were revised for loosening or considered to be loose radiologically. Nine shoulders underwent reoperation for infection (n = 3), fracture of the humeral tray (n = 2), aseptic glenoid loosening (n = 1), and instability (n = 3). No periprosthetic fractures occurred. Implantation of this particular short cementless humeral component at the time of TSA or RSA was associated with a low rate of adverse radiological findings on the humeral side at mid-term follow-up. Our data do not raise any concerns regarding the use of a short stem in TSA or RSA. Cite this article: Bone Joint J 2019;101-B:610-614.

Short-stem anatomical shoulder replacement—a systematic review

In shoulder arthroplasty, there is a trend for shorter humeral implants to facilitate stem revision and preserve bone stock. This review evaluates the clinical and radiographic outcome of anatomical total shoulder replacement with uncemented humeral short stems. A systematic review was performed using PubMed and Cochrane databases. The search terms “short stem” (all) and “shoulder” (title/abstract) were used. The minimum follow-up was 20 months. The demographic data, clinical outcome (pain, range of motion, outcome scores), radiographic outcome (humeral bone adaptations, humeral loosening, glenoid loosening), risk for high radiographic bone adaptations, complications, and revision were determined. Ten studies comprising 653 shoulder arthroplasties were included in the analysis. At an average follow-up of 20–64 months, the clinical parameters of pain, range of motion, and outcome scores improved significantly in all studies. The most frequent radiographic finding was calcar resorption in 15–71% of patients. High filling ratio, lack of metaphyseal porous coating, and poor bone quality were associated with high bone adaptation. The radiographic changes did not influence the clinical outcome in any study. In 13 of 653 patients (2%), humeral stem loosening was observed leading to stem revision in nine patients, with one study reporting eight of 73 patients with humeral stem loosening. The average weighted complication rate was 6% and the average weighted revision rate was 4%. The short- to medium-term results of uncemented anatomical short-stem shoulder arthroplasty are encouraging and the clinical results are comparable to other 3rd- and 4th-generation shoulder arthroplasties. Further studies with longer follow-up are needed to evaluate and understand why the radiographic changes occur and to prove the theory of bone-sparing revision surgeries.

Randomised clinical trial assessing migration of uncemented primary total hip replacement stems, with and without autologous impaction bone grafting.

Uncemented stems in primary total hip replacement (THR) are concerning in the elderly due to ectatic femoral canals and cortical thinning resulting in higher incidence of fracture and subsidence in this population. To obviate this concern, the authors developed a technique using autologous impaction bone grafting to achieve a better fitting femoral stem. The aim of this randomised clinical trial was to assess the efficacy of the technique. From 2013 to 2015, a total of 98 consecutive participants (100 primary THR procedures) were inducted into a single-institution, single-blinded, randomised clinical trial assessing, with radiostereometric analysis (RSA), the efficacy of autologous impaction bone grafting in uncemented primary THR compared with traditional uncemented primary THR technique. The primary outcome measure was femoral component migration using RSA. Secondary outcomes were post-operative proximal femoral bone density (using DEXA), hip function and quality of life using Oxford Hip Score (OHS) and Short Form-12 Health Survey (SF-12), hip pain and patient satisfaction. There was no difference in femoral component stability (p > 0.5) or calcar resorption between the Graft and No Graft Groups at two years. There was also no difference in OHS, SF-12, pain or satisfaction between the Graft and No Graft Groups at two years (p > 0.39). Autologous impaction bone grafting in uncemented primary THR has shown its short-term post-operative outcomes to be equivalent to standard uncemented technique, whilst offering a better fit in patients who are between femoral stem sizes. ACTRN12618000652279.

Midterm results of anatomic total shoulder arthroplasty with a third-generation implant

Anatomic total shoulder arthroplasty (TSA) provides reliable, reproducible, and durable results; however, outcomes of many modern TSA systems are lacking. The present study reports early to midterm results of a third-generation TSA system using a traditional-length press-fit humeral stem and cemented glenoid. A retrospective review was conducted of TSA patients with minimum 2-year clinical follow-up. Patient-reported outcome measures, including Simple Shoulder Test, American Shoulder and Elbow Surgeons Total, visual analog scale for pain, 12-Item Short Form Health Survey, and Single Assessment Numeric Evaluation, as well as measured active motion (forward elevation, external and internal rotation), were recorded at preoperative and postoperative intervals. Preoperative midglenoid axial computed tomography scans were used to evaluate eccentric glenoid wear, humeral head subluxation, and glenoid version. Most recent postoperative radiographs were used to evaluate glenoid loosening, humeral loosening, lesser tuberosity union, and medial calcar resorption. Patient satisfaction at final follow-up was reported as excellent, good, satisfied, or unsatisfied. There were 267 patients who met inclusion criteria, with a mean age of 70.9 years and mean clinical follow-up of 47 months. Average glenoid retroversion was 9.7°, and 27% had eccentric glenoid wear. At final follow-up, measured motion and nearly all patient-reported outcome measures showed significant improvements, with 75.6% of patients rating their satisfaction as excellent. No patient was considered "at risk" for humeral stem loosening. Glenoid radiolucencies were seen in 13.5% of shoulders (7 gross loosening). Five patients were revised to reverse TSA. TSA using a third-generation traditional-length press-fit stem and cemented glenoid provides excellent early to midterm outcomes with low rates of loosening and high rates of excellent satisfaction.

Excellent Mid-Term Results of a New Polished Tapered Modular Cemented Stem: A Study of 113 Hip Replacements with Minimum 5-Year Follow-Up

BackgroundThis prospective cohort study reports the medium-term clinical and radiographic results of 113 hips treated with a hybrid total hip replacement (THR) with a new cemented tapered cobalt-chrome (Co-Cr) stem with a titanium (Ti) modular neck (ProfemurXm®).MethodBetween October 2008 and December 2010 we performed 115 consecutive hybrid THR with the ProfemurXm® in 105 patients.ResultsSurvivorship of the implant (stem and modular neck) at a mean of 6.5 years (min 5-max 8) was 100% with the endpoint revision for any reason. No implant was at risk for revision or showed signs of loosening. The mean Harris Hip Score was 89/100, mean Oxford Hip Score was 43/48, mean WOMAC was 91/100. No patient had thigh pain, no patient reported squeaking. There were no dislocations in this cohort. No implant showed development of radiolucent lines (RLL), either at the stem-cement or cement-bone interface. No hip showed osteolysis or calcar resorption. The mean femoral subsidence of the stem within the cement mantel was 0.31 mm (range 0-0.6 mm) after 6.5 years. With the use of this modular stem, 93% of hips showed no measurable leg length difference after THR, and leg length could be restored within a 5-mm limit in 99% of hips.ConclusionsThe mid-term results of this new polished stem were excellent, without adverse effects from the use of modularity.

Radiological assessment of outcome and complications of total hip arthroplasty

Introduction: Proximal femoral fractures fixation demonstrates overall failure rates in the range of 3%-12%, with non-union in 2% to 5%, device penetration in 2% to 12%, and varus collapse in 5%-11%. The primary indication for secondary surgery is relief of pain resulting from the aforementioned complications Methodology: The deformity, range of movements (ROM) and limb length discrepancy were measured for all the patients in the standard proforma made for each patient. All the patients were assessed using Harris hip score Results: Post-operative radiological complications were very few. Calcar resorption was noticed in 1 case postoperatively, and dislocation occurred in one case which was reduced by closed reduction with immobilization for 6 weeks and later followed by gait training with no evidence of further dislocations. None of the post-operative cases got infected till the last follow-up indicating satisfactory radiological outcome in total hip arthroplasty Conclusion: The complications like aseptic loosening and particle wear requiring re-revision have not been found in our study

Radiographic evaluation of hip implants.

Serial radiographs are the mainstay in the longitudinal assessment of hip implants. The prosthesis, periprosthetic bone, and juxta-articular soft tissues are inspected for fracture, periosteal reaction, stress shielding, calcar resorption, osteolysis, bony remodeling, metallic debris, and heterotopic ossification. Comparison radiographs best confirm implant migration, subsidence, and aseptic loosening. Infection, particle disease, reaction to metal, and mechanical impingement are important causes of postsurgical pain, but in their earliest stages they may be difficult to diagnose using radiographs. This article addresses the role of radiography following hip arthroplasty.

The Effect of Hydroxyapatite Coating on Long-term Results of Total Hip Arthroplasty with Hydroxyapatite-coated Anatomic Femoral Stem.

PurposeTo evaluate the clinical and radiological results, as well as the survival rate, associated with total hip arthroplasty using a hydroxyapatite (HA)-coated anatomical femoral stem at a follow-up of ≥12 years.Materials and MethodsFrom April 1992 to May 1997, 86 patients (102 hips) underwent total hip arthroplasty with a HA-coated ABG I (Anatomical Benoist Giraud; Howmedica) hip prosthesis. The average age at the time of surgery was 53.4 years and the mean duration of follow-up was 17.1 years (range, 12.1-21.0 years). The Harris hip score (HHS) and radiographic assessments of thigh pain were used to evaluate the clinical results. We observed osteointegration, cortical hypertrophy, reactive line, calcar resorption and osteolysis around the femoral stems. The survival rate of the femoral stems was evaluated by using the span of time to a revision operation for any reasons was defined as the end point.ResultsThe mean HHS was 50.5 preoperatively and 84.2 at the time of last follow-up. Osteolysis only around the HA-coated proximal portion of the femoral stem was observed in 72 hips, cortical hypertrophy all around the distal portion of the femoral stem was observed in 38 hips, and calcar resorption was observed in 44 hips. A reactive line was observed in 13 hips, but was unrelated to component loosening. Stem revision operations were performed in 24 (23%) hips due to osteolysis (14 hips), fracture (5 hips) and infection (5 hips). The femoral stem survival rate was 75% over the mean duration of follow-up.ConclusionTotal hip arthroplasty using a HA-coated anatomical femoral stem showed necessitated a high rate of revision operations due to osteolysis around the femoral stem in this long term follow-up study.

Fretting and Corrosion in Modular-Neck Total Hip Arthroplasty Femoral Stems

During total hip arthroplasty, use of a modular femoral neck on a stemmed implant allows optimization of neck anteversion, length, and offset, resulting in more accurate balance. We performed a retrospective analysis of a consecutive cohort of patients who had undergone total hip arthroplasty with a modular-neck hip system with ceramic-on-ceramic bearings. We reviewed the results in fifteen patients who had received an ABG II dual modular hip system (Stryker Orthopaedics, Mahwah, New Jersey) from May 2007 to August 2008. Anteroposterior radiographs of the pelvis were reviewed and scored with regard to medial calcar erosion. Magnetic resonance imaging (MRI) was performed to assess for adverse local tissue reaction around the hip joint. Calcar resorption was correlated with subsequent MRI findings. Retrieval analysis was performed on the implants removed at revision. The mean duration of follow-up for all patients was 42.3 months (range, thirty-three to sixty months). Cobalt-ion levels were elevated in all patients; chromium levels were within the normal range. Medial femoral calcar erosion was noted in seven of the fifteen cases. All patients with grade-2 or 3 calcar erosion on radiographs had positive MRI findings consistent with adverse local tissue reaction. At the time of writing, seven patients had undergone revision arthroplasty. Intraoperatively, tissue staining with tissue and bone necrosis and pseudotumor formation were observed in all revision cases. Histological analysis confirmed the presence of metal-on-metal synovitis, with changes similar to those seen with metal-on-metal bearings. The ABG II dual modular hip system is associated with a high rate of early failure secondary to fretting and corrosion at the femoral neck-stem taper. The component has subsequently been recalled and is no longer in use. Surgeons using modular hip systems with a titanium stem and cobalt-chromium neck should be vigilant about annual follow-up with radiographs, and use of MRIs as indicated.

Clinical and Radiographic Evaluation of a Commercially Pure Cancellous-Structured Titanium Press Fit Total Hip Prosthetic Stem: Ten-Year Followup of the “Natural Hip” Femoral Stem

This study evaluates the outcomes of 92 hip arthroplasties using a press fit, tapered, split tip, proximally porous ingrowth (CSTi) femoral stem (Zimmer Natural Hip) in consecutive hip arthroplasty patients followed for an average of ten years postoperatively (range 5–16 years). Patients were functionally and radiographically evaluated using Harris Hip Scores and plain radiographs assessing postarthroplasty groin or thigh pain and radiographic signs of stem subsidence, proximal femoral fixation, stress shielding, and related calcar resorption. At followup of 5–10 years, the incidence of groin pain and thigh pain was 9.1% and 3.6%, respectively. This incidence improved over time. Beyond 10 years of followup, groin pain was 2.7% and thigh pain zero. In 89% of cases, there was solid contact between the calcar and the undersurface of the stem collar. Five cases were revised for instability (5.4%). The Harris Hip Scores and the incidence of thigh or groin pain were very favorable compared to other reported press fit total hip arthroplasty stems and not significantly different across a broad age range. There were no cases of stem loosening of failure of bony ingrowth into the stem.

Three-Year Prospective Clinical and Radiological Results of a New Flexible Horseshoe Acetabular Cup

We report the three-year results of a new flexible, horseshoe-shaped acetabular cup, with a carbon fibre reinforced polyetheretherketone (CFR-PEEK) bearing surface. The 3 mm thick composite cup is designed to conserve acetabular bone stock and reproduce a near-physiological stress distribution to the adjacent bone. The cup is intended to articulate against a large diameter ceramic femoral head to produce a low-wear bearing couple that generates minimal wear debris. A prospective, two-centre clinical study of the MITCH PCR cup was started in January 2007, to verify its safety and performance. Twenty-five MITCH PCR cups were implanted by three surgeons. There were 12 men and 13 women, with a mean age of 67.9 years (range 57.4 to 74.9). The mean Oxford hip score improved from 19.6 (SD 7.5) preoperatively to 43.5 (SD 7) at 3 years. The mean Harris hip score improved from 52.9 (SD 7) to 91.4 (SD 13.8) and the Euroqol-5D score increased from 62.6 (SD 18.4) to 82.8 (SD 19). One revision of the acetabular cup was undertaken at 21 months for squeaking. This has been investigated and modification of the articular geometry has resolved the problem, on in-vitro testing. Radiological analysis showed good early osseointegration of the MITCH PCR cup. However at three years, five cases of acetabular component migration and calcar resorption were observed. Three patients have subsequently undergone revision of the acetabular cup, at 41, 42 and 50 months respectively. The cause of the osteolysis is the subject of on-going investigation.

Clinical outcomes of cemented double-tapered titanium femoral stems: a minimum 5-year follow-up

BackgroundThe clinical outcomes and radiological findings for cemented titanium stems remain controversial. In 2004, we produced a straight-collared double-tapered stem made from a titanium alloy with a smooth surface for cemented total hip arthroplasty. In this study, we retro-spectively examined the mid-term outcomes of this stem. MethodsWe retrospectively reviewed 61 hips that had undergone primary cemented total hip arthroplasty with a collared smooth double-tapered titanium alloy femoral stem, after a minimum of 5 years (mean 6.1, range 5.0–7.3). Patients were evaluated preoperatively and postoperatively with the Merle d'Aubigne and Postel hip score. Radiographic examination was performed for evaluation of the cementing technique, the alignment of the stem, subsidence within the cement mantle, radiolucent lines at the cement-bone or cement-stem interface, cortical hypertrophy, and calcar resorption. ResultsThe clinical evaluation by the Merle d'Aubigne and Postel hip score was improved from 9.4 ± 1.9 preoperatively to 15.9 ± 1.6 at the time of final follow-up. The overall survival rate was 100% at 7 years, when radiological loosening or revision for any reasons was used as the endpoint. Five stems subsided less than 1mm vertically. Nonprogressive radiolucence at the cement-bone interface occurred in six hips, without osteolysis. Cortical hypertrophy was observed in five hips and second-degree calcar resorption in 11 hips. ConclusionsOur results in this study show good outcomes for cemented, collared, smooth, double-tapered titanium alloy femoral stems at a minimum follow-up of 5 years.

Wear is Reduced in THA Performed with Highly Cross-linked Polyethylene

Highly cross-linked polyethylene (HCLPE) has been used extensively to decrease osteolysis and related implant failure in THA. We compared the wear rate of HCLPE and noncross-linked conventional PE (CPE) liners and the rate of radiographic calcar resorption and osteolysis in young patients (35-60 years of age) who underwent THA by one surgeon. Thirty-four patients (41 THAs) who received a hybrid THA using a HCLPE liner were match-paired for age, gender, body mass index, and diagnosis with a group of patients who underwent THA with identical implants but with a CPE liner. The minimum followup was 4 years (average, 5.3; range, 4-8 years). Using the Livermore measurement technique, the averages of total wear of the HCLPE and CPE liners were 0.01 mm (range, -0.23-0.4) and 0.64 mm (range, 0-1.7), respectively. The average annual wear was less for the HCLPE than the noncross-linked PE (0.002 mm, range, -0.05-0.1 versus 0.12 mm, range, 0-0.29, respectively). Four hips in the HCLPE group and 23 in the CPE group had calcar resorption measuring averages of 2.5 mm (range, 2-3) and 7.5 mm (range, 1.8-23.8), respectively. Periprosthetic osteolysis occurred in two and eight hips in the HCLPE and CPE groups, respectively. Longer followup is needed to determine if these findings will result in improved implant survivorship. Level III, therapeutic study.

The Effect of Collar on Aseptic Loosening and Proximal Femoral Bone Resorption in Hybrid Total Hip Arthroplasty

This study compared proximal femoral bone resorption in hybrid total hip arthroplasty cases that had poor or good contact between the collar and proximal medial femoral neck. A total of 94 patients (102 hips) comprised the study group. Mean patient age was 52 years, and mean follow-up was 4.86 years. Bone resorption of the proximal femur was evaluated with immediate postoperative and follow-up anteroposterior and lateral radiographs. Statistical analysis using the Mann-Whitney test showed no significant difference between the groups that had good or poor contact. The collar did not prevent calcar resorption even when ideal contact was achieved.