Dorr Type Research Articles

Cementless rectangular stems yield satisfactory results in osteoporotic bones.

The present study aims to investigate the effects sof osteoporosis on prosthesis survival by comparing the femoral stem survival rates of patients with poor and relatively good bone quality. We retrospectively investigated 61 patients with collum femoris fractures who were treated with cementless rectangular stems between 2011 and 2015 in the Orthopaedics and Traumatology Clinic of Taksim Training and Research Hospital. The preoperative pelvic anterior-posterior radiographs of the patients were evaluated. The patients were evaluated according to the Dorr classification, and no case with a type A femur was found. The patients were divided into two groups as advanced osteoporotic type C and moderate osteoporotic type B. Thirty patients were type B according to the Dorr classification and 31 were osteoporotic type C. The femoral component survival was evaluated using the Engh and ARA criteria. The relationship of the ARA score with type B and type C groups was evaluated. The median ARA score was five (min 3-max 6) for both types. These two groups were also statistically compared concerning the ARA scores using the Mann-Whitney U test, which revealed no statistically significant difference (p=0.24 >0.05). The Engh values, another criterion for the survival of femoral components, were also compared. The median Engh values were 16.5 (min 9-max 24) for the Dorr type B group and 14 (min 9-max 24) for the type C group. According to the Mann-Whitney U test, there was no significant difference between the Engh values of the two groups (p=0.061 >0.05). Lastly, no statistically significant difference was found in the ARA or Engh loosening scores between the type C advanced osteoporotic group and the type B moderate osteoporotic group. Our study supports the conclusion that cementless hip arthroplasty can be applied even in advanced elderly and osteoporotic patients without additional intraoperative or postoperative risks.

An Analysis of the Potential Relationship between Crowe Type and Lower Extremity Morphology in Patients with Developmental Dysplasia of the Hip.

PurposeTo test whether Crowe type is related to femoral alignment and leg length discrepancy by evaluating the preoperative lengths and coronal alignment of femurs, pelvic parameters and hip morphology of patients who underwent primary hip arthroplasty due to coxarthrosis secondary to developmental dysplasia of the hip (DDH).Materials and MethodsMedical records of patients with coxarthrosis secondary to DDH who were treated with total hip arthroplasty at Department of Orthopaedics and Traumatology, Istanbul University Faculty of Medicine between 2008 and 2017 were reviewed. The mechanical axis of lower limbs was analyzed; pelvic height and femoral and tibial lengths were measured. All femurs were classified according to the Dorr classification.ResultsA total of 97 patients were eligible for analysis and were diagnosed with unilateral DDH (n=51) or bilateral DDH (n=46). In those diagnosed with unilateral DDH, the affected pelvis, femur, and tibia were often shorter than the unaffected side. In those diagnosed with bilateral DDH, femoral and pelvic lengths were unpredictable. In the femoral coronal alignment test, data varied widely but were within normal limits. The difference in the Dorr types of femurs was significant between dysplastic and normal sides of patients with unilateral DDH (P=0.001) but not those with bilateral DDH.ConclusionEspecially in patients with unilateral DDH, pelvic heights and femoral and tibial lengths on the affected side may be shorter compared with unaffected side regardless of the Crowe type. Femoral coronal alignment is unpredictable for both groups. Careful preoperative analyses of femoral coronal alignment and pelvic length are advised.

Clinical outcomes of PFNA-II in the Asian intertrochanteric fracture patients: Comparison of clinical results according to proximal nail protrusion

PurposeThis study intended to explore the clinical outcomes of PFNA-II, one of the commonly used fixation devices for intertrochanteric fractures and the association of clinical results with the extent of proximal nail protrusion. Materials and MethodsOf 315 cases that underwent internal fixation using PFNA-II between September 2010 and June 2018 among intertrochanteric fracture patients aged over 65 years, a total of 86 patients with an ability to communicate clearly and a minimum follow-up of 6 months were retrospectively reviewed. We classified the subjects according to PFNA-II protrusion over the greater trochanter area on anteroposterior radiographs. Differences between the two groups were examined by comparing demographic characteristics including gender, age, height, weight and BMI, instrumental characteristics including PFNA nail size, nail diameter, blade length and blade position, radiologic characteristics including reduction quality, Dorr type and bone union, and clinical characteristics including GT pain,VAS score and Harris Hip Score (HHS). ResultsA total of 86 cases were divided into 30 (34.9%) in the protrusion group (group A) and 56 (65.1%) in the non-protrusion group (group B). No significant difference was found in demographic characteristics such as gender, age, height, weight and BMI between the two groups. Two groups had no statistically significant difference in PFNA nail length, nail diameter and blade length, but showed a statistically significant difference in blade position.At the latest follow-up, the mean HHS shows no statistically significant difference between the two groups. On the contrary, the number of patients complaining of GT pain and VAS score were statistically significantly higher in group A. Removal of metal implants was performed in two patients in the protrusion group due to a complaint of persistent GT pain. ConclusionNail protrusion over the greater trochanter area occurs frequently after the surgical treatment of intertrochanteric fracture using PFNA-II. When the nail protruded into the greater trochanter, the number of patients who clinically complained of pain was statistically significantly high. We recommend a modification to the PFNA-II that would further shorten the proximal nail end suitable for the Asian population to achieve better clinical results in the fixation of intertrochanteric fractures.

Primary total hip arthroplasty using an uncemented Wagner SL stem in elderly patients with Dorr type C femoral bone

BackgroundThe purpose of this study was to review retrospectively the primary total hip arthroplasties operated upon with the cementless Wagner Self-Locking stem in patients with type C femoral bone.MethodsTwenty-eight total hip arthroplasties were performed in 25 patients aged ≥ 60 years using a cementless Wagner Self-Locking femoral component between 2006 and 2011. According to Dorr’s criteria, all 28 femora were classified as type C bone. All patients were treated with THA using a cementless Wagner cone prosthesis. Clinical and radiologic evaluations were performed on all patients.ResultsMean follow-up period was 125 ± 10.5 months (range 96 to 156 months). Average Harris hip score pre-operatively was 46 ± 9 (range 39 to 62) and at the last follow-up was 90 ± 9 (range 83 to 98). The stem to canal fill is calculated as percentages on the operative side at three distinct levels: just below the lesser trochanter, at midstem, and 1 cm above the tip of the component on anteroposterior radiograph. The mean proximal stem-to-canal fill percentages were 97% ± 2.1%, 95% ± 3.5%, and 88% ± 2.6%, respectively (anteroposterior view) and 92% ± 2.2%, 86% ± 1.9%, and 83% ± 2.5%, respectively (lateral view). Radiographic evaluation demonstrated good osteointegration of the implants in the follow-up.ConclusionsBased on the long-straight cylindrical tapered stem design, the cementless Wagner SL stem can achieve reliable stability by close apposition of the stem and wide stovepipe femoral canal from metaphysis to diaphysis in type C bone.

Midterm Results of Fourth-Generation Ceramic-On-Ceramic Total Hip Arthroplasty.

Purpose:There are limited reports for the results of the fourth-generation ceramic-on-ceramic (CoC) articulation total hip arthroplasty (THA). And, throughout the surgical experience, we encountered some cases of liner pulling-out phenomenon after liner fixation and femoral preparation. The objective of this study was to evaluate the incidence, risk factors of delta ceramic liner or head fractures, and also the clinical and radiological results of using the fourth-generation CoC articulation in THA.Patients and Methods:We retrospectively reviewed 242 patients (263 hips) who underwent primary THA using the fourth-generation CoC articulation with a minimum followup of 2 years. Demographic data, Harris Hip Score (HHS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Patient's satisfactory level were recorded. The radiological evaluation was used to evaluate the implant fixation and complications. Mean followup duration was 5.2 years.Results:Mean HHS and WOMAC score were significantly (P < 0.05) improved at the last followup. About 98.5% of the patients were satisfied with results of the surgery. All acetabular components were placed in adequate position and there was no osteolysis on acetabular or femoral components and subsidence of femoral stem. Four patients showed complications including one-liner fracture.Conclusion:Our midterm study demonstrated excellent clinical and radiological results with only one ceramic liner fracture. Moreover, the results of this study indicate that one possible cause of pulling-out phenomenon is the resonance effect during implantation in Dorr type A patients with the thick cortex. If the surgeon is aware of the liner malposition throughout the operation, the fourth-generation CoC articulation THA could be an outstanding treatment.

Application of bone-retaining femoral stem prosthesis in young patients with Dorr C femoral medullary cavity

To assess the clinical efficacy of Tri-Lock bio-short prosthesis in artificial total hip arthroplasty(THA) in young patients with Dorr type C femoral medullary cavity. From January 2010 to January 2014, 35 young patients(37 hips) with in the chimney-like femoral medullary cavity received Tri-Lock BPS prosthesis of THA, including 18 males(20 hips) and 17 females with an average age of (32.2±3.0) years old ranging from 21.2 to 38.5 years old. There were 16 cases of rheumatoid hip arthritis (17 hips), 8 cases of rheumatoid arthritis (9 hips), and 11 cases of aseptic necrosis of femoral head (11 hips). All cases were complicated with different degrees of osteoporosis. According to Singh index, 26 cases were classified as Grade III and 9 cases as Grade II. Biological prostheses were used for the acetabulum, with ceramic lining and full ceramic femoral head. The proximal femoral medullary cavity was Dorr type C on anteroposterior X-ray. After replacement, X-ray examination was performed to locate the prosthesis stem. Engh and Harris criteria were used to evaluate the stability of bone-prosthesis interface and hip function, respectively. Changes of hip movement pre-operation and at last follow-up were compared. All patients were followed up for 18 to 45 months(means 33.8 months). Harris hip scores in 35 cases (37 hips) increased significantly from preoperative 61.8±3.0 (51.2 to 73.5) to 93.3±6.5 (92.5 to 98.8) points at last follow-up (t=54.745, P<0.01). The hip mobility increased from (46.5±8.0)°(0° to 55°) before surgery to(101.2±10.5)°(85° to 130°) at the last follow-up, the difference was statistically significant(t=133.091, P<0.01). Immediately after surgery, the prostheses were tightly packed with the medullary cavity. At the final follow-up, 17 hips had significant femur cortical bone thickening;12 hips had varying degrees of stress occlusal bone resorption at proximal femoral, including 9 degree I(low femur density, round and blunt) and 3 degree II(involving small rotor) hips. Meanwhile, 15 hips had significant femur cortical bone thickening without thigh pain. The cone-shaped short Tri-lock biological short-stem can fill Dorr C chimney-like medullary cavity and effectively retain good proximal femoral bone mass. Titanium microporous coating on the surface can effectively increase the friction of the prosthesis. The short-stem end in the medullary cavity can effectively avoid the occurrence of coxa varus.

Subsidence and perioperative periprosthetic fractures using collarless hydroxyapatite-coated stem for displaced femoral neck fractures according to Dorr type

Hydroxyapatite (HA)-coated stem has been introduced to decrease complications and eventually achieve quicker implant ingrowth and long-term stability. The aim of this study was to determine subsidence rate and incidence of perioperative periprosthetic fracture (PPF) of uncemented collarless Corail stem for displaced femoral neck fractures according to Dorr type. A retrospective review of plain radiographs and clinical data was carried out to identify consecutive patients who underwent uncemented hip hemiarthroplasty using collarless HA-coated Corail stem between March 2010 and August 2014. The risk of subsidence and PPF according to Dorr type was evaluated. Dorr types A, B, and C were found in 66 (median age 74, 29.7%), 107 (median age 77, 48.2%), and 49 (median age 80, 22.1%) cases, respectively. Subsidence of stem occurred in eight (3.6%) cases. Dorr type had significant relationship (p < 0.05) with subsidence. Type C canals had higher rates of subsidence. PPFs occurred in 11 (5.0%) cases without showing significant difference among Dorr types not significant (n.s.). Female gender was not influential on subsidence (n.s.) and PPF (n.s.). Dorr type C had higher risk of subsidence when using uncemented collarless HA-coated stem. Dorr canal type had no bearing on risk of PPFs. Women did not have significantly higher risk of both subsidence and PPFs compared to men. A collarless fully HA-coated Corail stem had 3.6% of radiological subsidence and 5.0% of PPF risk.

Effect of Denosumab on Femoral Periprosthetic BMD and Early Femoral Stem Subsidence in Postmenopausal Women Undergoing Cementless Total Hip Arthroplasty.

ABSTRACTAntiresorptive denosumab is known to improve the quality and strength of cortical bone in the proximal femurs of osteoporotic women, but its efficacy in preventing periprosthetic bone loss and reducing femoral stem migration has not been studied in women undergoing cementless total hip arthroplasty. We conducted a single‐center, randomized, double‐blinded, placebo‐controlled trial of 65 postmenopausal women with primary hip osteoarthritis and Dorr type A or B proximal femur anatomy. The patients randomly received subcutaneous injections of denosumab 60 mg or placebo once every 6 months for 12 months, starting 1 month before surgery. The primary endpoint was the change in bone mineral density (BMD) of the proximal femur (Gruen zone 7) at week 48, and the secondary endpoint was stem subsidence measured by radiostereometric analysis (RSA) at week 48. Exploratory endpoints included changes in BMDs of the contralateral hip, lumbar spine and distal radius, serum levels of bone turnover markers, walking speed, walking activity, patient‐reported outcome measures, and radiographic assessment of stem osseointegration. The participants underwent vertebral‐fracture assessment in an extension safety study at 3 years. Denosumab significantly decreased bone loss in the medial femoral neck (zone 7) and increased periprosthetic BMD in the greater trochanteric region (zone 1) and lesser trochanteric region (zone 6). Denosumab did not reduce temporary femoral stem migration. The migration occurred mainly during the settling period (0 to 12 weeks) after implantation of the prosthesis. All of the stems osseointegrated, as evaluated by RSA and radiographs. There were no intergroup differences in functional recovery. Discontinuation of denosumab did not lead to any adverse events. In conclusion, denosumab increased periprosthetic BMD in the clinically relevant regions of the proximal femur, but the treatment response was not associated with any reduction of initial stem migration. © 2019 The Authors. JBMR Plus published by Wiley Periodicals, Inc. on behalf of the American Society for Bone and Mineral Research.

Subsidence of Hydroxyapatite-Coated Femoral Stem in Dorr Type C Proximal Femoral Morphology

BackgroundGood bone quality and proper proximal femoral morphology are thought to be necessary for tapered design, cementless femoral stems to resist subsidence. Using tapered, cementless stem for patients with stovepipe morphology or Dorr type C is controversial. The purpose of this study is to analyze (1) subsidence of the fully hydroxyapatite (HA)-coated, tapered, cementless stem in different morphology according to Dorr classification, (2) subsidence of the stem related to radiographic canal-fill ratio. MethodsThe digitized radiographs of 311 consecutive cementless primary total hip arthroplasty with fully HA-coated, tapered stem were retrospectively reviewed. Subsidence and the canal-fill ratio at 4 locations were evaluated postoperatively after a minimum of 2 years of follow-up. The threshold of subsidence >3 mm was considered as a clinically significant migration. ResultsA multivariate regression analysis of subsidence across Dorr type, controlling for age, gender, and intraoperative calcar fracture, demonstrated 0.40 mm (P = .28) and 0.18 mm (P = .51) greater subsidence in Dorr type C and B when compared to Dorr type A. Age, gender, and calcar fracture had no influence on subsidence, whereas greater canal-fill ratio at 2 cm below lesser trochanter resulted in significantly less subsidence (P = .02). Additionally, all variables did not affect the risk of having subsidence >3 mm. ConclusionThe proximal femoral morphology has no statistically significant effect on the subsidence of fully HA-coated stem. Therefore, this stem type might be a viable option for Dorr type C. Increasing the canal-fill ratio at metadiaphyseal junction may ensure the stability of the stem.

Cementless short-stem total hip arthroplasty in the elderly patient - is it a safe option?: a prospective multicentre observational study

BackgroundDue to its bone preserving philosophy, short-stem total hip arthroplasty (THA) has primarily been recommended for young and active patients. However, there may be benefits for elderly patients given a less invasive operative technique due to the short curved implant design. The purpose of this study was to compare the clinical and radiological outcomes as well as perioperative complications of a calcar-guided short stem between a young (< 60 years) and a geriatric (> 75 years) population.MethodsData were collected in a total of 5 centers, and 400 short-stems were included as part of a prospective multicentre observational study between 2010 and 2014 with a mean follow-up of 49.2 months. Preoperative femur morphology was analysed using the Dorr classification. Clinical and radiological outcomes were assessed in both groups as well as perioperative complications, rates and reasons for stem revision.ResultsNo differences were found for the mean visual analogue scale (VAS) values of rest pain, load pain, and satisfaction, whereas Harris Hip Score (HHS) was slightly better in the young group. Comparing both groups, none of the radiological parameters that were assessed (stress-shielding, cortical hypertrophy, radiolucency, osteolysis) reached differences of statistical significance. While in young patients aseptic loosening is the main cause of implant failure, in the elderly group particularly postoperative periprosthetic fractures due to accidental fall have to be considered to be of high risk. The incidence of periprosthetic fractures was found to be 0% in Dorr type A femurs, whereas in Dorr types B and C fractures occurred in 2.1 and 22.2% respectively.ConclusionsAdvanced age alone is not necessarily to be considered as contra-indications for calcar-guided short-stem THA, although further follow-up is needed. However, markedly reduced bone quality with femur morphology of Dorr type C seems to be associated with increased risk for postoperative periprosthetic fractures, thus indication should be limited to Dorr types A and B.Trial registrationGerman Clinical Trials Register; DRKS00012634, 07.07.2017 (retrospectively registered).

Techniques of Insertion and Early Clinical Impressions with a Short Curved Tissue Sparing Implant for Total Hip Arthroplasty (The French Experience)

Background: Total hip arthroplasty (THA) is one of the most effective orthopedic procedures, providing consistently high success rates across all population segments as measured by pain relief, improved function, and patient satisfaction. However clinical outcomes have been less favorable in young active patients, that lead to the re-development of metal on metal hip resurfacing (HR), with the most successful being the Birmingham Hip Replacement (BHR) introduced in 1997. Evolving complications due to increased metal ion debris has lead to a great reduction of use for all metal on metal (MOM) HR designs, leading many surgeons and patients to look for an alternative surgical selection. This search has focused on the development and use of short stems for THA. One such style of short stems is curved neck preserving designs. This paper will review our French experience with one of those designs.Materials and Methods: This is a retrospective review of four surgeons series of a short curved tissue sparing cementless femoral implant (TSI™ Hip Stem, Signature Orthopaedics) for THA. The femoral component was used with two different cementless acetabular styles (Mathys RM Pressfit, and Zimmer Biomet Allofit®). Results on the cups will not be revived in this paper. 150 TSI™ Stems by four surgeons at the same institution utilizing the posterior surgical approach since September 2016. 40% women, average age 66 years with extremes of 27 to 78 years. 10 cases of dysplastic hips, 6 cases of aseptic osteonecrosis, 1 fracture, 1 rheumatoid coxitis, and the rest primary coxathosis, with 7 patients operated on both hips at the same time. 23.3 % have been Dorr type A canal shape.Results: There has been no aseptic loosing, three femoral components have been explanted due to postoperative infection. There was one intra-operative femoral distal fracture in a Dorr type A bone profile during stem insertion. One posterior dislocation; there has been two patients with thigh pain with pathological bone scan, and one with low back pain and no leg length discrepancies greater than plus or minus 5 mm.Conclusion: This short curved tissue sparing implant has demonstrated excellent initial short-term results, with excellent implant stability, excellent medial calcar bone remodeling with one dislocated stem, two thigh pain and one patient with low back pain. One distal intra-operative fracture in a Dorr type A bone. This has now been addressed with the use of distal sizing gauges and the use of flexible reamers to open the distal canal prior to stem insertion. Removal of the infected stems demonstrated implant stability with early bone attachment in the proximal porous surface. The high neck resection allows for ease of revision and conversion implanting a new primary conventional length cementless stem design.There is a short but definitive learning curve in fitting the implant to the femoral neck versus the standard metaphyseal and diaphyseal conventional style stems.

An increase in the risk of excessive femoral anteversion for relatively younger age and types of femoral morphology in total hip arthroplasty with direct anterior approach.

Direct anterior approach (DAA) is known to diminish a dislocation risk and widely used for total hip arthroplasty (THA). On the other hand, anterior dislocation due to increasing stem anteversion and cup anteversion is an important complication. A retrospective analysis of 140 (male/female: 10/130) consecutive patients with 149 hips who had undergone primary THA in the period between 2011 and 2015 was conducted. Factors including age, gender, body mass index (BMI), and primary diagnosis were examined. Radiographic parameters including the Dorr proximal femoral types, cortical thickness index (CTI), canal flare index (CFI), and canal to calcar index were measured. To investigate relationships of combined anteversion (CA) with other factors, a stepwise regression analysis was performed. The mean age, BMI, and the follow-up period were 69.5 ± 10.3 years old, 23.4 ± 3.4 kg/m2, and 48.2 ± 13.6 months, respectively. The proximal femurs of the 149 hips were categorized as Dorr type A ( n = 33), type B ( n = 110), and type C ( n = 6). The mean CTI, CFI, and canal to calcar index were 0.56 ± 0.08, 4.15 ± 0.83, and 0.46 ± 0.09, respectively. The mean stem varus angle, radiographic inclination, and radiographic anteversion of the cup were 0.19 ± 1.63, 40.9 ± 6.0°, and 12.7 ± 3.5°, respectively. Stem anteversion measured by computed tomography (CT) axial image was 17.7 ± 12.0°. The mean radiographic inclination, radiographic anteversion (CTRA), and anatomical anteversion analyzed by Kyocera 3-D template were 40.8 ± 7.2°, 19.8 ± 6.6°, and 28.8 ± 10.0°, respectively. Mean CA defined as the sum of stem anteversion and CTRA was 37.5 ± 14.5°. To investigate relationships of CA with other factors, a stepwise regression analysis was performed and resulted in a model with age ( p < 0.001). In the same way, stem anteversion and CTRA were analyzed; only for the stem anteversion, the stepwise selection process resulted in a model with age ( p < 0.001) and the Dorr types ( p = 0.047). The risk of excessive femoral anteversion increases for relatively younger age and for types of femoral morphology according to the Dorr classification, moreover with an increase of CA in DAA-THA with cementless tapered-wedge stem.

Does Proximally Coated Single-Wedge Cementless Stem Work Well in Dorr Type C Femurs? Minimum 10-year Followup.

Background:Total hip arthroplasty (THA) with a proximally coated single-wedge (PSW) cementless stem had been generally considered not to be suitable for Dorr Type C femurs. This study compares the long term outcomes of PSW stem according to the type of proximal femoral geometry.Materials and Methods:307 primary THAs in 247 patients were performed with PSW cementless stem and followed up for over 10 years in this retrospective study. According to Dorr's criteria, 89 femurs were classified as Type A, 156 as Type B, and 62 as Type C. They were followed up for an average of 13.2 years (range 10.0–17.3 years). All the hips were evaluated clinically and radiologically.Results:There was no significant difference in stem survivorship and clinical outcomes including the incidence of thigh pain and the mean postoperative Harris hip score (HHS) in all three groups. No significant differences were observed in osteolysis, pedestal formation, or cortical hypertrophy among the groups. Radiolucent lines <2 mm in thickness in Gruen zone 4 and 7 (P = 0.003 and P = 0.044, respectively), spot-weld (P < 0.001), and stress shielding (P = 0.010) of proximal femur were more pronounced in Dorr C type femora than in Type A or B. Fifty-six intraoperative fractures were identified among 307 hips with PSW stems. The incidence of intraoperative or postoperative femoral fractures was not significantly different among the groups.Conclusions:From over a 10-year followup, the PSW stem provided a recommendable option with satisfactory outcomes and excellent stem survivorship regardless of the Dorr type.

Reproductibilité de la classification de Dorr et de ses index quantitatifs sur des radiographies standard

BackgroundThe Dorr classification is widely used to evaluate femoral bone quality, but it has no clear quantitative criteria. This study aimed to evaluate the reproducibility of the Dorr classification and examine its quantitative indices on plain radiographs, which are suitable for objective classification. HypothesisReproducibility of the Dorr classification is influenced by the clinical experience of the examiners, and radiographic indices are required for this classification. Materials and MethodsOne hundred and one patients were examined using their preoperative plain anteroposterior and lateral radiographs. To evaluate the reproducibility of the Dorr classification, the Dorr type of each patient was judged twice each by three expert hip surgeons and three junior hip surgeons. Indices measured using the plain radiographs were canal-to-calcar ratio, cortical index (CI), and canal flare index. A receiver operating characteristic curve was used to evaluate which measured parameters were suitable as indices for the Dorr classification, which was determined by the consultation among three expert hip surgeons. ResultsRegarding intra-examiner reproducibility, kappa coefficients for the three junior hip surgeons were 0.36, 0.62, and 0.65, whereas those for the three expert hip surgeons were 0.70, 0.86, and 0.87. Regarding inter-examiner reproducibility, the kappa coefficient for the junior hip surgeons was 0.32, whereas that for the expert hip surgeons was 0.52. The CI on the lateral radiograph had the largest area under the curve (AUC) between types A and B, whereas the CI on the anteroposterior radiograph had the largest AUC between types B and C. The respective cutoff points of the CI on the anteroposterior radiograph were 0.58 between types A and B and 0.49 between types B and C. The respective cutoff points of CI on the lateral radiograph were 0.45 between types A and B and 0.28 between types B and C. ConclusionThe intra-examiner reproducibility of the Dorr classification ranged from “fair” to “almost perfect”, whereas the inter-examiner reproducibility ranged from “fair” to “moderate”. Both were influenced by the level of clinical experience of the examiners. The most suitable index for classification using plain radiographs of the hip is the CI on anteroposterior and lateral radiographs. Level of evidenceIV, retrospective study.

Clinical and Radiological Outcomes of Rectangular Tapered Cementless Stem According to Proximal Femoral Geometry in Elderly Asian Patients.

PurposeA retrospective analysis of mid- to long-term clinical and radiological outcomes of Korean patients over 60 years of age who underwent hip arthroplasty using a cementless rectangular tapered stem according to Dorr proximal femur geography.Materials and MethodsFrom January 2007 to December 2013, 107 patients (112 hips) underwent hip arthroplasty using the C2 stem. The mean age of patients was 77.4 years (range, 60–91 years) and the mean follow-up duration was 91.1 months (range, 60–116 months). All patients were evaluated clinically and radiologically with special attention to Dorr femoral bone classification, implant fixation, radiolucent line (RLL), and thigh pain.ResultsAll implants demonstrated radiographic evidence of stable fixation by bone ingrowth without any change in position. The mean Harris hip score improved from 65.5±16.0 (preoperative) to 90.5±15.9 (final follow-up) (P<0.001). Incidence of RLLs, stress shielding, and thigh pain was highest in patients with Dorr type A (RLL, P=0.021; stress shielding, P=0.030; thigh pain, P<0.001). One stem revision was performed due to deep infection. The Kaplan–Meier survival rate of the femoral stem was 97.6%.ConclusionThe overall survival rate of the C2 stems was greater than 97%; there were no significant differences in survival of the C2 stem according to the Dorr classification. The incidences of RLL of thigh pain and RLL were significantly different among Dorr classifications and (highest in patients with Dorr type A).

Long-Term Results of Hip Arthroplasty Using Extensive Porous-Coated Stem-A Minimum Follow-Up of 15 Years.

Introduction:We report the clinical and radiographic results of hip arthroplasty using extensive porous-coated stems over 15 years in Korea.Methods:This retrospective study included 210 patients (268 hips) who underwent total hip arthroplasties (232 hips) and bipolar hemiarthroplasties (36 hips) between June 1996 and December 2002 for avascular necrosis of the femoral head, hip fracture, or osteoarthritis, after excluding those who died or were lost to follow-up. One senior author (K.H.M.) evaluated Harris Hip Score (HHS); limping gait; and leg length discrepancy, and 3 independent reviewers assessed the radiographic findings, including the level of stress shielding, Dorr classification, subsidence and loosening of femoral stem, heterotopic ossification (Brooker classification), osteolysis of acetabulum, wear rate of the polyethylene liner, component loosening, and revision rate.Results:The mean follow-up duration was 16.9 years and average age at operation was 50.9 years. The HHS improved at the last follow-up. Stress shielding was grade 1 in 185 hips, grade 2 in 35 hips, grade 3 in 37 hips, and grade 4 in 11 hips. Femoral stem subsidence was <3 mm in 4 hips and >3 mm in 6 hips. Femoral stems with stable bony ingrowth were observed in 258 hips, fibrous stable femoral stems in 4 hips, and unstable femoral stems in 6 hips. Heterotopic ossification was class 1 in12 and class 2 in 4 hips. Revision surgery was performed for periprosthetic osteolysis of cup (45 hips), recurrent dislocation (1), unstable femoral stem (1), and infection (1). The Kaplan-Meier survivorship at the 15-year follow-up was 86.2%. The survivorship of femoral stem at 15 years was 99.3%, and if including impending revision due to unstable femoral stem was 97.1%.Disscussion:This study has all the limitations inherent with a retrospective design. However, a large number of patients in this cohort operated on by a single surgeon and a long-term follow-up are some of the potential advantages of the current study.Conclusions:At the 15-year follow-up, extensive porous-coated stem showed relatively good survivorship even in geriatric patients (Dorr type C).

Comparison of initial stability and stem position of Preserve α and β stem for Dorr type C femoral neck fracture

Comparison of initial stability and stem position of Preserve α and β stem for Dorr type C femoral neck fracture

Reproducibility of the Dorr classification and its quantitative indices on plain radiographs

BackgroundThe Dorr classification is widely used to evaluate femoral bone quality, but it has no clear quantitative criteria. This study aimed to evaluate the reproducibility of the Dorr classification and examine its quantitative indices on plain radiographs, which are suitable for objective classification. HypothesisReproducibility of the Dorr classification is influenced by the clinical experience of the examiners, and radiographic indices are required for this classification. Materials and methodsOne hundred and one patients were examined using their preoperative plain antero-posterior and lateral radiographs. To evaluate the reproducibility of the Dorr classification, the Dorr type of each patient was judged twice each by three expert hip surgeons and three junior hip surgeons. Indices measured using the plain radiographs were canal-to-calcar ratio, cortical index (CI), and canal flare index. A receiver operating characteristic curve was used to evaluate which measured parameters were suitable as indices for the Dorr classification which was determined by the consultation among three expert hip surgeons. ResultsRegarding intra-examiner reproducibility, kappa coefficients for the three junior hip surgeons were 0.36, 0.62, and 0.65, whereas those for the three expert hip surgeons were 0.70, 0.86, and 0.87. Regarding inter-examiner reproducibility, the kappa coefficient for the junior hip surgeons was 0.32, whereas that for the expert hip surgeons was 0.52. The CI on the lateral radiograph had the largest area under the curve (AUC) between types A and B, whereas the CI on the anteroposterior radiograph had the largest AUC between types B and C. The respective cutoff points of the CI on the anteroposterior radiograph were 0.58 between types A and B and 0.49 between types B and C. The respective cutoff points of CI on the lateral radiograph were 0.45 between types A and B and 0.28 between types B and C. ConclusionThe intra-examiner reproducibility of the Dorr classification ranged from “fair” to “almost perfect”, whereas the inter-examiner reproducibility ranged from “fair” to “moderate”. Both were influenced by the level of clinical experience of the examiners. The most suitable index for classification using plain radiographs of the hip is the CI on anteroposterior and lateral radiographs. Level of evidenceIV, retrospective study.

Femoral Stem Survivorship in Dorr Type A Femurs After Total Hip Arthroplasty Using a Cementless Tapered Wedge Stem: A Matched Comparative Study With Type B Femurs

BackgroundThere is a lack of understanding on relationship between the femoral geometry and outcomes of total hip arthroplasty (THA). We investigated clinical and radiographic outcomes of THA using a cementless tapered wedge stem in patients with Dorr type A proximal femoral morphology and compared with those of type B femurs at a minimum follow-up of 5 years. MethodsWe analyzed 1089 hips (876 patients) that underwent THA using an identical cementless tapered wedge stem. We divided all femurs into 3 types (Dorr type A, B, and C). Type A and B femurs were statistically matched with age, gender, body mass index, and diagnosis by using propensity score matching. Clinical, radiographic results, and stem survivorship were compared between the matched 2 groups. ResultsA total of 611 femurs (56%) were classified as type A, 427 (39%) as type B, and 51 (5%) as type C. More radiolucent lines around femoral stems were found in type A femurs (7.8%) than in type B femurs (2.5%) (P < .001). Patients with radiolucency showed worse Harris Hip Score (86.2 points) compared with those without radiolucency (93.0 points) (P < .001). The stem survivorship of type A femur (97.8%) was lower than that of type B femur (99.5%) (P = .041). The reasons for femoral revision in type A femurs were periprosthetic fracture (67%), aseptic loosening (22%), and deep infection (11%). ConclusionsThis study showed a higher rate of complications after THAs using a cementless tapered wedge stem in Dorr type A femurs than those performed in type B femurs.

Proximal Femoral Shape Changes the Risk of a Leg Length Discrepancy After Primary Total Hip Arthroplasty

BackgroundTo evaluate how canal morphology affects the technical aspects of total hip arthroplasty, we investigated the effects of femoral cortical index (FCI) on the re-establishment of leg length at the conclusion of surgery. MethodsWe retrospectively reviewed age, gender, body mass index, and radiographs of 516 patients with osteoarthritis or osteonecrosis who underwent unilateral cementless primary total hip arthroplasty between 2008 and 2015. Patients were divided into level of FCI and leg length discrepancy (LLD). Each cohort was compared in terms of demographics and LLD. One-way analysis of variance and Kruskal-Wallis test were used. ResultsThe mean FCI and LLD were 0.6 ± 0.1 and 3.5 ± 6.3 mm, respectively. Utilization of an extended offset stem was highest with Dorr type A and B hips (P = .001). High FCI increased the risk of lengthening (P = .017) and low FCI increased the risk of shortening (P = .005). ConclusionA high FCI increases the probability of a leg length increase and a low FCI increases the probability of a leg length decrease. Surgeons might consider informing patients in advance of possible variation in leg length depending on the patients’ proximal femoral shape and bony quality.