Subsidence Of Femoral Component Research Articles

Contemporary outcomes of primary total hip arthroplasty in patients with inflammatory arthritis.

Contemporary outcomes of primary total hip arthroplasties (THAs) with highly cross-linked polyethylene (HXLPE) liners in patients with inflammatory arthritis have not been well studied. This study examined the implant survivorship, complications, radiological results, and clinical outcomes of THA in patients with inflammatory arthritis. We identified 418 hips (350 patients) with a primary diagnosis of inflammatory arthritis who underwent primary THA with HXLPE liners from January 2000 to December 2017. Of these hips, 68% had rheumatoid arthritis (n = 286), 13% ankylosing spondylitis (n = 53), 7% juvenile rheumatoid arthritis (n = 29), 6% psoriatic arthritis (n = 24), 5% systemic lupus erythematosus (n = 23), and 1% scleroderma (n = 3). Mean age was 58 years (SD 14.8), 66.3% were female (n = 277), and mean BMI was 29 kg/m2 (SD 7). Uncemented femoral components were used in 77% of cases (n = 320). Uncemented acetabular components were used in all patients. Competing risk analysis was used accounting for death. Mean follow-up was 4.5 years (2 to 18). The ten-year cumulative incidence of any revision was 3%, and was highest in psoriatic arthritis patients (16%). The most common indications for the 15 revisions were dislocations (n = 8) and periprosthetic joint infections (PJI; n = 4, all on disease-modifying antirheumatic drugs (DMARDs)). The ten-year cumulative incidence of reoperation was 6.1%, with the most common indications being wound infections (six cases, four on DMARDs) and postoperative periprosthetic femur fractures (two cases, both uncemented femoral components). The ten-year cumulative incidence of complications not requiring reoperation was 13.1%, with the most common being intraoperative periprosthetic femur fracture (15 cases, 14 uncemented femoral components; p = 0.13). Radiological evidence of early femoral component subsidence was observed in six cases (all uncemented). Only one femoral component ultimately developed aseptic loosening. Harris Hip Scores substantially improved (p < 0.001). Contemporary primary THAs with HXLPE in patients with inflammatory arthritis had excellent survivorship and good functional outcomes regardless of fixation method. Dislocation, PJI, and periprosthetic fracture were the most common complications in this cohort with inflammatory arthritis.

Penalty for Switching Implants? Assessing the Learning Curve With aCollarless, Tapered Wedge Cementless Femoral Component.

Surgeon learning curve associated with a tapered wedge femoral implant as measured by early femoral component subsidence and 90-day risk of reoperation was evaluated. The first 451 patients undergoing primary, cementless total hip arthroplasty by a single, fellowship-trained arthroplasty surgeon with a tapered wedge stem design were retrospectively reviewed. Early radiographic femoral component subsidence during the first 6 weeks postoperatively and 90-day reoperations was recorded. When stratified by approach, there was no association between date of surgery and femoral component subsidence in the posterior approach (P-value for linear trend over time= 0.44). In the direct anterior approach, there was a significant association between date of surgery and early femoral component subsidence (P-value for linear trend over time= 0.01). For both approaches, there was an increase in implanted stem size relative to templated stem size over time (P < .01 and P= .03, respectively). There was no association between the date of surgery and risk of 90-day reoperation (P= .45). In a single surgeon's initial use of a tapered cementless wedge stem, early femoral component subsidence was not impacted by the surgeon's learning curve when the posterior approach was utilized. Although subsidence was associated with date of surgery in the direct anterior cohort, this was not associated with increased risk of 90-day reoperation. Should a surgeon adopt a new tapered-wedge stem, these findings suggest that the stem is forgiving both in relation to subsidence and 90-day reoperation risk when appropriate surgical technique is utilized.

High grade femoral stem subsidence in uncemented hip hemiarthroplasty - A radiographic analysis and an early prediction while treating femoral neck fractures.

Femoral component subsidence is a known risk factor affecting almost all hip replacements using a collarless, cement-less stems. High grade subsidence >5mm is functionally limiting to the patient. Early analysis and prediction of this complication on the immediate post-operative radiographs will help surgeons to opt for alternative solutions to mitigate this complication. A retrospective study including 116 patients, who underwent cement-less bipolar hemi-arthroplasties treated from 2020-2022 were included in the study. Body Mass Index (BMI) and pre-operative American Society Anesthesiologist (ASA) score was retrieved from the medical records. Post operative radiographs on postoperative day two, at four weeks and at eight weeks were evaluated. Dorr's score, initial subsidence ratio (ISR) , stem angulation, proximal stem-canal fit (PSCF) ratio, distal stem-canal fit (DSCF) ratio, medial flare modifier (MFM) were recorded. A total of 18 patients showed subsidence over 5mm on radiographs evaluated at four weeks. The mean high-grade stem subsidence was 13.5mm +/- 2.67. Evaluating their respective postoperative day two radiographs- ISR was >1 in 16 out of 18 patients (89%), PSCF ratio <0.75 in 83% and DSCF ratio <0.5 in 78% patients. All these patients had a neutral/negative MFM. BMI >25 (p<0.05) and ASA >3 (p<0.001) correlated with a higher degree of stem subsidence. A lower BMI and ASA score accompanied by a positive MFM were protective factors against femoral stem subsidence. A higher ISR along with a PSCF ratio <0.75 and DSCF ratio <0.5, were highly predictive of stem subsidence over 5 mm.

THE ANTERIOR FEMORAL CORTICAL WINDOW AS AN ALTERNATIVE TO EXTENDED TROCHANTERIC OSTEOTOMY IN REVISION HIP SURGERY: EVOLUTION OF SURGICAL TECHNIQUE AND OUTCOMES IN 22 CONSECUTIVE CASES

When removing femoral cement in revision hip surgery, creating an anterior femoral cortical window is an attractive alternative to extended trochanteric osteotomy. We describe our experience and evolution of this technique, the clinical and radiological results, and functional outcomes.Between 2006 and 2021 we used this technique in 22 consecutive cases at Whanganui Hospital, New Zealand. The average age at surgery was 74 years (Range 44 to 89 years). 16 cases were for aseptic loosening: six cases for infection.The technique has evolved to be more precise and since 2019 the combination of CT imaging and 3-D printing technology has allowed patient-specific (PSI) jigs to be created (6 cases). This technique now facilitates cement removal by potentiating exposure through an optimally sized anterior femoral window.Bone incorporation of the cortical window and functional outcomes were assessed in 22 cases, using computer tomography and Oxford scores respectively at six months post revision surgery. Of the septic cases, five went onto successful stage two procedures, the other to a Girdlestone procedure.On average, 80% bony incorporation of the cortical window occurred (range 40 −100%). The average Oxford hip score was 37 (range 22 – 48). Functional outcome (Oxford Hip) scores were available in 11 cases (9 pre-PSI jig and 2 using PSI jig). There were two cases with femoral component subsidence (1 using the PSI jig).This case series has shown the effectiveness of removing a distal femoral cement mantle using an anterior femoral cortical window, now optimized by using a patient specific jig with subsequent reliable bony integration, and functional outcomes comparable with the mean score for revision hip procedures reported in the New Zealand Joint Registry.

Deep Learning for Radiographic Measurement of Femoral Component Subsidence Following Total Hip Arthroplasty.

Femoral component subsidence following total hip arthroplasty (THA) is a worrisome radiographic finding. This study developed and evaluated a deep learning tool to automatically quantify femoral component subsidence between two serial anteroposterior (AP) hip radiographs. The authors' institutional arthroplasty registry was used to retrospectively identify patients who underwent primary THA from 2000 to 2020. A deep learning dynamic U-Net model was trained to automatically segment femur, implant, and magnification markers on a dataset of 500 randomly selected AP hip radiographs from 386 patients with polished tapered cemented femoral stems. An image processing algorithm was then developed to measure subsidence by automatically annotating reference points on the femur and implant, calibrating that with respect to magnification markers. Algorithm and manual subsidence measurements by two independent orthopedic surgeon reviewers in 135 randomly selected patients were compared. The mean, median, and SD of measurement discrepancy between the automatic and manual measurements were 0.6, 0.3, and 0.7 mm, respectively, and did not demonstrate a systematic tendency between human and machine. Automatic and manual measurements were strongly correlated and showed no evidence of significant differences. In contrast to the manual approach, the deep learning tool needs no user input to perform subsidence measurements. Keywords: Total Hip Arthroplasty, Femoral Component Subsidence, Artificial Intelligence, Deep Learning, Semantic Segmentation, Hip, Joints Supplemental material is available for this article. © RSNA, 2022.

Survivorship and Outcomes of Femoral Neck Preserving Stems in Primary Total Hip Arthroplasty

BackgroundShort-stem femoral implants (SSFIs) promote the preservation of bone in the femoral neck, reduce soft tissue disruption, and facilitate minimally invasive surgical techniques. The purpose of this study was to report the revision rate, complication rate, patient satisfaction, patient-reported outcomes, and radiographic outcomes of patients who underwent total hip arthroplasty (THA) with the Alteon Neck Preserving Femoral Stem (ANPS). MethodsA prospectively maintained database was reviewed which analyzed 92 THAs between the years 2016 and 2018. Patient-reported outcomes, patient satisfaction, complication rates, and radiographic outcomes were assessed at 2-5 years postoperatively. ResultsThe final cohort consisted of 63 hips. Five patients (7.9%) underwent revision surgery and 2 (3.2%) had other complications not requiring revision. Survivorship when considering only the femoral component was 93.7% at an average of 41.4 months of follow-up. The average postoperative Oxford Hip Score (41.5 ± 8.3) and Harris Hip Score (77.9 ± 16.6) demonstrated significant improvement among our nonrevised patients, respectively (P < .001). Radiographs demonstrated spot welding in 56% of arthroplasties most commonly in Gruen Zones 2, 3, and 13 and that femur radiolucencies were visualized in 58% predominantly along the distal aspect of the stem. Radiographic femoral component subsidence was present in 9.7% of patients. ConclusionThe ANPS may be less reliable than previously reported. Our cohort’s revision rate was unacceptably high with 6.3% requiring revision surgery for femoral component loosening in less than 5 years. Surgeons should consider the challenges and prohibitive failure rate associated with SSFIs before routine usage in THA.

Favorable mid-to-long-term results of impaction bone grafting using a fresh frozen allograft bone with cemented stem for the treatment of Paprosky IV femoral bone defects

BackgroundFemoral revision surgery in patients with substantial bone loss is challenging. Impaction bone grafting using a cemented stem can be a good solution for reconstruction of the femur with poor bone stock and extensive bone loss. This study aimed to evaluate the mid-to-long-term clinical and radiographic results of impaction bone grafting using a cemented stem for Paprosky IV femoral bone defects. MethodsThirteen patients (13 hips) who underwent revision total hip arthroplasty with impaction bone grafting using a cemented stem and were followed up for at least 5 years were enrolled in this study. In all patients, a sufficient amount of fresh frozen bone of good quality was used. When cortical segmental defects were present, peripheral reinforcement with metal mesh and strut allograft was performed. The average follow-up duration was 11.1 (range, 5.3–15.1) years. The clinical and radiographic outcomes were reviewed at the final follow-up. ResultsThe average Harris hip score was 82.5 (range, 79–94), and the average University of California, Los Angeles activity score was 5.6 (range, 4–8) at the final follow-up. Radiographic assessment revealed an average femoral component subsidence level of 0.67 (range, 0.05–2.81) mm. There were no complications, except one case (7.6%) of periprosthetic fracture. ConclusionsImpaction bone grafting using a cemented stem yielded excellent mid-to-long-term outcomes. It is a reliable technique for Paprosky IV femoral bone defects, and even when severe femoral cortical bone defects are present, long-term stability can be obtained using a metal mesh and/or strut allograft.

Differences in femoral component subsidence rate after THA using an uncemented collarless femoral stem: full weight-bearing with an enhanced recovery rehabilitation versus partial weight-bearing

BackgroundFemoral component subsidence is a known risk factor for early failure of total hip arthroplasty (THA) using cementless stems. The aim of the study was to compare an enhanced recovery concept with early full weight-bearing rehabilitation and partial weight-bearing on stem subsidence. In addition, the influence of patient-related and anatomical risk factors on subsidence shall be assessed.MethodsOne hundred and fourteen patients underwent primary cementless THA and were retrospectively analyzed. Sixty-three patients had an enhanced recovery rehabilitation with early full weight-bearing and 51 patients had rehabilitation with partial weight-bearing (20 kg) for 6 weeks. Postoperative subsidence was analyzed on standing pelvic anterior–posterior radiographs after 4 weeks and 1 year. Subsidence was measured in mm. Anatomical and prosthetic risk factors (stem size, canal flare index, canal fill ratio as well as BMI and demographic data) were correlated.ResultsFemoral stem subsidence rate was significantly higher for the group with an enhanced recovery concept compared to the group with partial weight-bearing at the first radiological follow up after 4 weeks [2.54 mm (SD ± 1.86) vs. 1.55 mm (SD ± 1.80)] and the second radiological follow up after 1 year [3.43 mm (SD ± 2.24) vs. 1.94 (SD ± 2.16)] (p < 0.001, respectively). Stem angulation > 3° had a significant influence on subsidence. Canal flare index and canal fill ratio showed no significant correlation with subsidence as well as BMI and age.ConclusionIn the present study, cementless stem subsidence was significantly higher in the group with enhanced recovery rehabilitation compared to partial weight-bearing. Small absolute values and differences were demonstrated and therefore possibly below clinical relevance. Anatomical radiological parameters and anthropometric data did not appear to be risk factors for stem subsidence.

Are Elevated Nicotine and Cotinine Levels Associated with Early Femoral Component Subsidence in Press-Fit, Primary Total Hip Arthroplasty?

AbstractTobacco exposure negatively affects bone mineral density and early osseointegration of surgical implants. We sought to determine if elevated nicotine and/or cotinine levels prior to primary total hip arthroplasty (THA) are associated with early femoral component subsidence. We hypothesize that tobacco users will have higher rates of readmission/reoperation and increased radiographic subsidence. We conducted an institutional review of 75 patients (average age = 52.9 years; 55% females; body mass index = 31.3) who underwent THA from April 2017 to January 2018. Immediate postoperative radiographs were compared with those obtained at 2 to 6 weeks postoperatively to determine early femoral component subsidence. Of the 75 patients, 10 (13.3%) had early radiographic femoral component subsidence ≥ 2 mm. In this group, preoperative nicotine levels were significantly elevated (7.2 vs. 1.5ng/mL; p = 0.04), whereas preoperative cotinine levels did not statistically differ (108.3 vs. 33.8 ng/mL; p = 0.45). A significantly greater magnitude of subsidence was seen in those with elevated preoperative nicotine levels compared with those with normal levels (1.7 vs. 0.5 mm; p = 0.04). The mean time to radiographic follow-up was 2.6 weeks. Surgical approach, implant type, categorical variables, and patient readmission were not associated with ≥ 2 mm of early subsidence. There was a single reoperation for periprosthetic fracture, but none was related to instability from subsidence. Early femoral component subsidence was more prevalent in patients with elevated preoperative nicotine levels. Rates of readmission/reoperation at 90 days did not differ between those with and without elevated tobacco markers. Clinically relevant thresholds of preoperative nicotine and/or cotinine values are needed to better delineate appropriate surgical candidates to achieve optimal surgical outcomes.

Modular Fluted Tapered Stems in Aseptic Oncologic Revision Total Hip Arthroplasty: A Game Changer?

BackgroundModular fluted tapered (MFT) stems are the most frequently used femoral component in revision total hip arthroplasties (THAs). Despite this, no data are available on how they perform in revision THA for oncologic salvage. This is a unique population, often with severe bone loss and prior radiation that extends the limits of uncemented femoral reconstruction. The aims of this study were to evaluate the implant survivorship, radiographic results, and clinical outcomes of MFT stems used for revision oncologic salvage. MethodsWe identified 17 patients treated initially with primary THA for an oncologic diagnosis (15 primary oncologic, 2 metastatic disease) who underwent subsequent femoral revision with an MFT stem. Mean age at revision was 66 years and 35% of patients were female. Mean follow-up was 4 years. Before revision, 5 of 17 had undergone local radiation. ResultsTen-year survivorship free from aseptic loosening was 100%. The survivorship free of any reoperation was 76%. There were no femoral component fractures. Three patients were revised for recurrent instability, and 1 patient underwent irrigation and debridement for an acute infection. At most recent follow-up, no patient had radiographic evidence of progressive femoral component subsidence or failure of osteointegration. The mean Harris Hip Score improved from 29 preoperatively to 76 postoperatively (P < .0001). ConclusionIn this series of patients with cancer, many of whom had severe bone loss and/or prior local radiation, being treated with revision THA, there were no revisions for femoral component loosening and no cases of implant fracture. Level of EvidenceIII.

A Plethora of Complications from Paget Disease.

In and of itself, Paget disease can be a challenging condition for patients to live with and for orthopaedists to treat. Moreover, as this edition of “Case Connections” illustrates, this mysterious bone-remodeling anomaly can trigger additional orthopaedic complications, including fractures and advanced arthritis. This month’s cases also illustrate that orthopaedic surgery in a zone of pagetic bone can be especially tricky, due in part to the apparent potential of Paget disease to “spread.” Total hip arthroplasty (THA) is one viable approach to treating Paget disease of the hip, but in the March 11, 2015, JBJS Case Connector, Amundsen et al. reported on a case in which the onset of Paget disease soon after THA led to stem loosening that necessitated revision. The seventy-seven-year-old man in this case had two years previously undergone a left THA for posttraumatic arthritis that included a cementless stem, cobalt-chromium head, and polyethylene liner. Radiographs made six months after the arthroplasty showed normal bone morphology, and the patient was symptom-free for the subsequent twelve months. Eighteen months after the procedure, however, he began experiencing hip pain and noticed a mass on the proximal aspect of the right tibia. Left hip radiographs showed femoral component subsidence with cortical thickening and expansion of the greater trochanteric region. Radiographs of the right tibia showed a mixed lytic and sclerotic lesion of the anterior cortex, characteristic of mixed-phase Paget disease. Upon physical exam, surgeons noted a 10-cm × 3-cm firm, nontender mass over the proximal tibial crest, and a bone scan showed areas of increased activity in the proximal half of the left femur …

Short stem total hip arthroplasty in patients with rheumatoid arthritis.

Total hip arthroplasty (THA) has proven successful in patients with rheumatoid arthritis (RA). Patients with RA often require multiple revisions, and bone conservation is mandatory. A variety of short stems is currently available with mid-term results for osteoarthritis. This retrospective study evaluated mid-term clinical results of short stem THA in a series of patients with RA. Between 2005 and 2009, a total of 105 cementless short stems were implanted in patients with RA. Average patient age at the time of the index THA was 44.2 years, and average length of follow-up was 5 years. Clinical evaluation included physical examination and documentation of potential adverse events during the postoperative period. No radiographic failures occurred. Femoral and cup components showed some minor radiolucencies with sclerotic lines, but none involved 100% of the bone-prosthesis interface. Complications included femoral component subsidence in 2 hips after initial full weight bearing; 1 case resolved after 3 months, and the other case was revised to a standard shaft. One intraoperative dorsolateral stem tip perforation occurred with revision to a conventional length stem. Migration in 1 cup led to revision without removal of the short stem implant. No infections or joint dislocations were observed. The transfer of the short stem concept to an additional treatment option for patients with RA proved successful in the early to mid-term postoperative period. Complications and revisions were limited to early migration and early loosening of the implants in line with the results reported in the literature of cementless conventional THA in patients with RA.

The effect of a collar and surface finish on cemented femoral stems: a prospective randomised trial of four stem designs

The optimal design for a cemented femoral stem remains a matter of debate. Over time, the shape, surface finish and collar have all been modified in various ways. A clear consensus has not yet emerged regarding the relative merits of even the most basic design features of the stem. We undertook a prospective randomised trial comparing surface finish and the effect of a collar on cemented femoral component subsidence, survivorship and clinical function. One hundred and sixty three primary total hip replacement patients were recruited prospectively and randomised to one of four groups to receive a cemented femoral stem with either a matt or polished finish, and with or without a collar. At two years, although there was a trend for increased subsidence in the matt collarless group, this was not statistically significant (p = 0.18). At a mean of 10.1 years follow-up, WOMAC scores for the surviving implants were good, (Range of means 89-93) without significant differences. Using revision or radiographic loosening as the endpoint, survivorship of the entire cohort was 93 % at 11 yrs, (CI 87-97 %). There were no significant differences in survivorship between the two groups with polished stems or the two groups with matt stems. A comparison of the two collarless stems demonstrated a statistically significant difference in survivorship between polished (100 %) and matt (88 %) finishes (p = 0.02). In the presence of a collar, surface finish did not significantly affect survivorship or function. Between the two collarless groups a polished surface conferred an improved survivorship.

Clinical Comparison of THA With a Standard-length or Short Femoral Component

The purposes of this 2-part study were to determine whether reduced distal femoral component geometry allows for routinely larger component sizes to be used and whether clinical or radiographic outcomes differ between total hip arthroplasty (THA) patients treated with either standard-length or short femoral components. Femoral component size and ongrowth surface area were retrospectively compared in a group of bilateral THA patients that had both a standard-length component and a contralateral short component. Then, clinical and radiographic outcomes were compared between matched groups of THA patients that had either a standard-length or short femoral component. The use of the short component resulted in a significantly larger femoral component size being used (P=.01), and the potential ongrowth surface area was significantly larger for the short component than for the standard component (median, 36.69 vs 35.55 cm2; P=.02). In the matched-pairs analysis, no group differences were noted in modified Harris Hip Scores (P=.43) or femoral component subsidence (P=.35), but there was a significantly greater prevalence of radiolucent lines in Gruen zone 8 with the short component (P=.008). The use of a short femoral component was associated with consistently larger component sizes being used, which corresponded with a larger potential ongrowth surface area. Short-term clinical and radiographic outcomes did not differ between standard-length and short femoral components. Studies are necessary to determine whether the increased proximal ongrowth surface area may result in improved long-term fixation or, on the contrary, may increase the risk of periprosthetic fracture.

Cementless two-staged total hip arthroplasty for chronic periprosthetic infection

To determine the clinical outcomes of two-staged cementless revision arthroplasty for the treatment of deep periprosthetic infection after total hip arthroplasty. Twenty-three patients with deep periprosthetic infection treated with a standard protocol of two-staged cementless revision hip arthroplasty were enrolled in this study. There were 9 male patients and 14 female patients with an average age of 64 years (range, 52-78 years). In all cases, antibiotics-loaded cement spacers were implanted after removal of all the prosthetic components and thorough debridements had been done. All patients had a minimum of 2 weeks of intravenous antibiotics followed by 4 weeks of oral antibiotics after implant removal. After a mean interval of 6.7 months (3-28 months), revision arthroplasties were carried out with cementless femoral components followed by 2 weeks of intravenous antibiotics and 4 weeks of oral antibiotics. The mean follow-up period was (4.3±3.5) years. There were 2 cases of recurrent infections in this study. Intraoperative periprosthetic fractures were observed in 3 patients. One patient had dislocation of the implanted spacer during the interval period and 2 patients had hip dislocation after reimplantation. Mild subsidence of femoral component occurred in 1 patient. There were no cases of loosening of femoral components and cementless acetabular components in patients without infection recurrence. The Harris hip score increased from a preoperative mean of 36±13 to 85±13 at 12 months after reimplantation. Using cementless prostheses in two-staged revisions of hip periprosthetic infections can provide low rate of infection recurrence and good implant stability, but cautions must be taken when treating patients with infection caused by multidrug-resistant organisms.

Reduced Femoral Component Subsidence with Improved Impaction Grafting at Revision Hip Arthroplasty

Despite stem subsidence being a major complication of femoral impaction bone grafting in cemented revision hip arthroplasty, few studies have distinguished subsidence at the prosthesis-cement interface from that at the cement-bone interface. It is unknown how technique developments intended to improve the procedure influence stability of the stem. We used a sensitive technique to measure subsidence of a cemented polished collarless double-taper stem at each interface after femoral impaction grafting and compared subsidence, radiographic loosening, complications, and reoperations over three series of hips defined by technique developments. Three series were defined: Series 1 (n = 23, irradiated allograft), Series 2 (n = 12, double-washed, size-profiled graft, nonirradiated bone, long stems as required), and Series 3 (n = 21, modular tamps). Stem subsidence was analyzed with Ein Bild Röntgen Analyse software. Radiographic loosening, complications, and reoperations were also determined. The median subsidence at 12 months for Series 1, 2, and 3 were 2.1, 0.5, and 0.7 mm at the prosthesis-cement interface and 1.3, 0.1, and 0.1 mm at the cement-bone interface. There were two postoperative Vancouver B periprosthetic fractures in Series 1, four hips were revised for loosening in Series 1, and there were no fractures or loosening in Series 2 and 3 at minimum 2 years' followup. There were no surviving hips radiographically classified as possibly or probably loose. Evolution in techniques of femoral impaction grafting in this study were associated with reduced subsidence of the stem at both the prosthesis-cement interface and cement-bone interface when compared to the original series. Concurrent with reduced stem subsidence was the absence of periprosthetic fracture, radiographic loosening, and complications requiring rerevision.

Extended Trochanteric Osteotomy for 2-Stage Revision of Infected Total Hip Arthroplasty

We evaluate the rate of osteotomy healing, implant stability, and eradication of infection when an extended trochanteric osteotomy, with interval placement of an antibiotic-impregnated cement spacer and delayed osteotomy fixation, is used to treat the chronically infected total hip arthroplasty. Thirteen cases were followed for a minimum of 2 years. All patients had complete healing of the extended trochanteric osteotomy within 6 months. At an average follow-up of 39 months, recurrent infection occurred in 3 (23%) patients. Femoral component subsidence of 5 mm occurred in 2 patients, both of which had recurrent infection. Extended trochanteric osteotomy with interval placement of an articulating antibiotic-impregnated cement spacer and delayed osteotomy fixation permits reliable healing of the osteotomy.

ＲＡ股に対するセメントレス人工股関節置換術の短期成績―ステム側のＸ線学的検討

Fifty-seven primary cementless total hip arthroplasties (THAs) were performed in 48 patients with rheumatoid arthritis. The average length of follow-up was 2.4 years (range; 1.1 to 4.4 years).The average age of these 48 patients at the time of surgery was 56.9 years (range; 36 to 78 years). In all patients Kyocera Per Fix HA prosthesis was used.Clinical evaluation based on the JOA score indicated significant improvement from 36.8 points preoperatively to 67.4 points postoperatively. Three patients (5%) complained of thigh pain. There was no evidence of roentgenographic failure such as femoral component subsidence, loosening or osteolysis. Spot welds contacting the porous surfaces were observed in 52 hips (91%). None of the hips showed radiolucent lines adjacent to the porous-surfaced portion of the stems. All femoral components showed bone ingrown fixation. These findings suggest that cementless stem may be successful in rheumatoid patients.

Automated image analysis technique for measurement of femoral component subsidence in total hip joint replacement

A new technique for the measurement of subsidence of the femoral components is proposed. The method relies on the implantation of two ball markers around the femoral stem. A single radiographic image of the hip is analysed using image-processing techniques to minimize subjectivity related to manual identification of landmarks. Dimensions of the stem are used to correct for magnification and out-of-plane rotations resulting from radiographic positioning. This technique has been applied to a specific design of implant (Exeter™). A study of the effect of radiographic positioning has been conducted using a cadaveric bone phantom. Results for the variation in the measurement of axial migration compared to the neutral position (in millimetres) were: 0.942 (10° extension); 0.347 (20° flexion); −0.435 (40° internal rotation); 0.187 (30° external rotation) for distances measured between the bone marker and the implant. Results for distances measured between the implant and the cement centralizer were: 0.107 (10° extension); −0.277 (20° flexion); 0.085 (40° internal rotation); 0.280 (30° external rotation). The variations from within a more realistic range of positions demonstrate that axial migration measurements of ca. 0.5 mm between the bone and implant, and less than 0.3 mm between the implant and the bone cement, may be expected.

Femoral component fixation with and without intramedullary plug. A 6-year follow-up.

A total of 113 patients underwent a cemented total hip replacement (THR) operation involving femoral component fixation either without the use of a distal intramedullary plug (n = 57, group 1) or with the plug (n = 56, group 2). We studied the femoral component fixation radiographically at on average 6 years after THR. The cement coating was assessed as technically good in 86% and 95% of groups 1 and 2, respectively. There was radiographically diagnosable loosening of the femoral component at the follow-up in 25 cases in which stems were inserted without the intramedullary plug, and in 6 cases in those with the plug (P < 0.0008), and the mean subsidence of the femoral component was 5 mm in group 1 and 1.5 mm (P < 0.0003) in group 2, respectively. Osteolytic changes around the femoral component were noticed in both groups in equal numbers and with no statistical difference. The use of a distal intramedullary plug in the cementation of the femoral stem results in a better cement coating, reduces femoral component subsidence and ameliorates the loosening rates.