Outcome of a hemispherical porous-coated acetabular component with a proximally hydroxyapatite-coated anatomical femoral component: an update at 23 to 26 years' follow-up

AIMS: We previously reported the long-term results of the cementless Duraloc-Profile total hip arthroplasty (THA) system in a 12- to 15-year follow-up study. In this paper, we provide an update on the clinical and radiological results of a previously reported cohort of patients at 23 to 26 years´ follow-up. PATIENTS AND METHODS: Of the 99 original patients (111 hips), 73 patients (82 hips) with a mean age of 56.8 years (21 to 70) were available for clinical and radiological study at a minimum follow-up of 23 years. There were 40 female patients (44 hips) and 33 male patients (38 hips). RESULTS: All acetabular and femoral components were well fixed and showed signs of bone ingrowth. Nine acetabular components were revised due to wear-osteolysis-related problems and four due to late dislocation. The probability of not having component revision at 25 years was 83.2% (95% confidence interval (CI) 74.5 to 91.8; number at risk 41). Acetabular osteolysis was observed in ten hips. The mean femoral head penetration was 1.52 mm (sd 0.8) at 15 years and 1.92 mm (sd 1.2) at 25 years. Receiver operating characteristic (ROC) analysis revealed that mean femoral penetration with a value of 0.11 mm/year or more was associated with the appearance of osteolysis. The 25-year Kaplan-Meier survival with different endpoints was 89.9% for acetabular osteolysis (95% CI 83.3 to 96.5), 92.1% for proximal femoral osteolysis (95% CI 86.1 to 98.2), and 75.5% for femoral osteopenia (95% CI 66.5 to 84.5). CONCLUSION: The Duraloc-Profile THA system showed excellent long-term bone fixation. Nevertheless, monitoring is recommended in order to detect wear and late dislocations in this population that was relatively young at the time of surgery. Cite this article: Bone Joint J 2019;101-B:378-385.

The evolution of an uncemented acetabular component in alumina-on-alumina total hip arthroplasty has improved clinical outcome: a prospective, comparative five- to 15-year follow-up study.

AIMS: To determine the effect of a change in design of a cementless ceramic acetabular component in fixation and clinical outcome after total hip arthroplasty PATIENTS AND METHODS: We compared 342 hips (302 patients) operated between 1999 and 2005 with a relatively smooth hydroxyapatite coated acetabular component (group 1), and 337 hips (310 patients) operated between 2006 and 2011 using a similar acetabular component with a macrotexture on the entire outer surface of the component (group 2). The mean age of the patients was 53.5 (14 to 70) in group 1 and 53.0 (15 to 70) in group 2. The mean follow-up was 12.7 years (10 to 17) for group 1 and 7.2 years (4 to 10) for group 2. RESULTS: No hips were revised due to complications related to bearing fracture or to stem loosening. A total of 15 acetabular components were revised for aseptic loosening in group 1 and two in group 2. The survival rate for acetabular component aseptic loosening at eight years was 96.8% (95% confidence interval (CI) 94.8 to 98.7) for group 1 and 99.2% (95% CI 98.0 to 100) for group 2. The risk for aseptic loosening of the acetabular component was higher in group 1 (p = 0.04, Hazard Ratio (HR) 4.99), dysplastic acetabula (p = 0.01, HR 4.12), components outside Lewinnek´s zone (p < 0.001, HR 6.13) and in those with a hip rotation centre distance greater than 5 mm (p = 0.005, HR 4.09). CONCLUSION: Alumina ceramic-on-ceramic THA is an excellent option for young patients. Although newer components appeared to improve fixation, acetabular reconstruction is essential to obtain a satisfactory outcome. Cite this article: Bone Joint J 2017;99-B:749-58.

[Survey on the use and behaviour of metal-metal hip replacements in Spain]. / Encuesta sobre el uso y comportamiento de las prótesis de cadera metal-metal en España.

BACKGROUND: Following medical device alerts published in different countries of problems with metal-on-metal total hip replacements, the Spanish Agency of Medicines and Medical Devices (AEMPS) in collaboration with the Spanish Hip Society Surgery designed a national survey to gather information on the use and behaviour of these hip implants. METHODS: The survey consisted of a questionnaire sent by e-mail to 283 clinical centre recipients of metal-on-metal hips to be filled in by surgeons with expertise in the field. RESULTS: A total of 257 questionnaires were completed. The response rate of the clinical centres was 36.7%. A total of 97.7% of the responses reported that clinical and radiological follow-ups are carried out, and 79.6% undertook metal ion analyses (chromium and cobalt). A large majority (83.6%) of the responders who had who used surface implants, and 70% of those with large-head implants reported peri-operative complications. The most common complication was pain (25% with surface implants and 30.8% with large-head implants). Currently 80.8% of those responding were considering abandoning implanting of these hip replacements. CONCLUSIONS: Despite the many limitations to this study, the survey has allowed us to obtain in a quick first view of the implant scenario of Metal on Metal hip implants in Spain, and to determine the type of patient implanted, the time of implantation, and the experience/expertise of the surgeons, and the type of follow-up carried out.

Factors influencing regional variability in the rate of total knee arthroplasty.

BACKGROUND AND PURPOSE: Geographic variations in knee arthroplasty have been detected through international surveys. We aim to investigate in this study the influence of aging index, health budget, and number of orthopedic surgeons in the regional variations of the primary and revision TKA rate in a single European country, Spain. MATERIAL AND METHODS: Inpatient database of knee arthroplasty procedures for years 1997 to 2010 was obtained from the Spanish Ministry of Health, including 393,714 primaries and 37,037 revisions, segregated for each of the 17 regional health services in Spain. Crude and adjusted rates (direct method with total Spanish population per year) were calculated and used as dependent variables. Aging index, regional health budget, and number of orthopedic surgeons per region were used as independent variables in a Kruskal-Wallis test and a negative binomial regression analysis model. RESULTS AND CONCLUSIONS: With a mean crude rate for Spain of 76 primary TKA and 7 revision surgeries per 10(5) population and year, the mean adjusted rate per region oscillated between 702 and 27 primary TKA and 87 and 3 revisions per 10(5). A model was adjusted confirming the influence of aging index, health budget, and number of surgeons, but regional variations remained partly unexplained by these factors.

New polyethylenes in total hip replacement: A ten- to 12-year follow-up study.

Between 1999 and 2001, 90 patients underwent total hip replacement using the same uncemented acetabular and femoral components with a 28 mm metallic femoral head but with prospective randomisation of the acetabular liner to either Durasul highly cross-linked polyethylene or nitrogen-sterilised Sulene polyethylene. We assessed 83 patients at a minimum follow-up of ten years. Linear penetration of the femoral head was estimated at six weeks, six and 12 months and annually thereafter, using the Dorr method, given the non-spherical shape of the acetabular component. There was no loosening of any component; only one hip in the Sulene group showed proximal femoral osteolysis. The mean penetration of the femoral head at six weeks was 0.08 mm (0.02 to 0.15) for the Durasul group and 0.16 mm (0.05 to 0.28) for the Sulene group (p = 0.001). The mean yearly linear penetration was 64.8% lower for the Durasul group at 0.05 mm/year (sd 0.035) for the Sulene group and 0.02 mm/year (sd 0.016) for the Durasul (p < 0.001). Mean linear femoral head penetration at ten years was 61% less in the Durasul than Sulene group. Highly cross-linked polyethylene gives excellent results at ten years.

European multidisciplinary consensus statement on the use and monitoring of metal-on-metal bearings for total hip replacement and hip resurfacing.

INTRODUCTION: There is an ongoing debate about the optimal use of metal-on-metal (MoM) bearings in total hip replacement, since there are uncertainties about local and systemic adverse effects due to wear and corrosion of these bearings. Despite various national recommendations, efforts to achieve international harmonization of specific evidence-based recommendations for best practice are still lacking. HYPOTHESIS: An international consensus study group should be able to develop recommendations on the use and monitoring of MoM bearings, preferably at the European level, through a multidisciplinary approach, by integrating the perspectives of various stakeholders. MATERIALS AND METHODS: Twenty-one experts representing three stakeholder groups and eight countries participated in this European consensus study, which consisted of a consensus meeting, subsequent structured discussion, and consensus voting. RESULTS: The current statement defines first of all benefits, local and systemic risks, as well as uncertain issues related to MoM bearings. Safety assessment after implantation of MoM comprises all patients. A closer follow-up is recommended for large head MoM (≥36mm) and resurfacing. In these implants basic follow-up should consist of x-rays and metal ion measurement of cobalt in whole blood, performed with GF-AAS or ICP-MS. Clinical and/or radiographic abnormality as well as elevated ion levels needs additional imaging (ultrasound, CT-scan and/or MARS-MRI). Cobalt values less than 2 µg/L are probably devoid of clinical concern, the threshold value for clinical concern is expected to be within the range of 2-7 µg/L. DISCUSSION: This is the first multinational, interdisciplinary, and multiprofessional approach for developing a recommendation for the use and monitoring of MoM bearings in total hip replacement. The current recommendations are in partial agreement with previous statements regarding the extent of follow-up and imaging techniques. They however differ from previous communications regarding measurement of metal ions and especially the investigated medium, technique, and eventual threshold levels. LEVEL OF EVIDENCE: Level V, expert opinion/agreement conference.

The extent of the bone defect affects the outcome of femoral reconstruction in revision surgery with impacted bone grafting: a five- to 17-year follow-up study.

We report the results of 79 patients (81 hips) who underwent impaction grafting at revision hip replacement using the Exeter femoral stem. Their mean age was 64 years (31 to 83). According to the Endoklinik classification, 20 hips had a type 2 bone defect, 40 had type 3, and 21 had type 4. The mean follow-up for unrevised stems was 10.4 years (5 to 17). There were 12 re-operations due to intra- and post-operative fractures, infection (one hip) and aseptic loosening (one hip). All re-operations affected type 3 (6 hips) and 4 (6 hips) bone defects. The survival rate for re-operation for any cause was 100% for type 2, 81.2% (95% confidence interval (CI) 67.1 to 95.3) for type 3, and 70.8% (95% CI 51.1 to 90.5) for type 4 defects at 14 years. The survival rate with further revision for aseptic loosening as the end point was 98.6% (95% CI 95.8 to 100). The final clinical score was higher for patients with type 2 bone defects than type 4 regarding pain, function and range of movement. Limp was most frequent in the type 4 group (p < 0.001). The mean subsidence of the stem was 2.3 mm (SD 3.7) for hips with a type 2 defect, 4.3 mm (SD 7.2) for type 3 and 9.6 mm (SD 10.8) for type 4 (p = 0.022). The impacted bone grafting technique has good clinical results in femoral revision. However, major bone defects affect clinical outcome and also result in more operative complications.

Stress-shielding of the proximal femur using an extensively porous-coated femoral component without allograft in revision surgery: a 5- to 17-year follow-up study.

Revision surgery of the hip was performed on 114 hips using an extensively porous-coated femoral component. Of these, 95 hips (94 patients) had a mean follow-up of 10.2 years (5 to 17). No cortical struts were used and the cortical index and the femoral cortical width were measured at different levels. There were two revisions for aseptic loosening. Survivorship at 12 years for all causes of failure was 96.9% (95% confidence interval 93.5 to 100) in the best-case scenario. Fibrous or unstable fixation was associated with major bone defects. The cortical index (p = 0.045) and the lateral cortical thickness (p = 0.008) decreased at the proximal level over time while the medial cortex increased (p = 0.001) at the proximal and distal levels. An increase in the proximal medial cortex was found in patients with an extended transtrochanteric osteotomy (p = 0.026) and in those with components shorter than 25 cm (p = 0.008). The use of the extensively porous-coated femoral component can provide a solution for difficult cases in revision surgery. Radiological bony ingrowth is common. Although without clinical relevance at the end of follow-up, the thickness of the medial femoral cortex often increased while that of the lateral cortex decreased. In cases in which a shorter component was used and in those undertaken using an extended trochanteric osteotomy, there was a greater increase in thickness of the femoral cortex over time.

Outcome of a hemispherical porous-coated acetabular component with a proximally hydroxyapatite-coated anatomical femoral component: a 12- to 15-year follow-up study.

We reviewed 111 hemispherical Duraloc series-500 acetabular components with a minimum follow-up of 12 years. The mean clinical and radiological follow-up was 13.4 years (12 to 15). A Profile hydroxyapatite-coated anatomical femoral component was used in each case. Six patients had a late dislocation, for whom the polyethylene liner was exchanged. Each acetabular component was well fixed and all femoral components showed signs of bone ingrowth. The mean rate of femoral head penetration was 0.10 mm/year (0.021 to 0.481). The probability of not developing femoral cortical hypertrophy and proximal osteopenia by 12 years was 80.2% (95% confidence interval, 72.7 to 87.6) and 77.5% (95% confidence interval, 69.7 to 85.2), respectively. Despite these good clinical results, further follow-up is needed to determine whether these prostheses will loosen with time.

New polyethylenes in total hip replacement: a prospective, comparative clinical study of two types of liner.

Ultra-high-molecular-weight polyethylene sterilised in the absence of air and highly cross-linked polyethylene have been used to avoid osteolysis and loosening in total hip replacement. Our prospective randomised study has assessed the results using two different polyethylenes associated with the same prosthetic design. We assessed 45 Allofit acetabular components with a Sulene-polyethylene liner of conventional polyethylene gamma sterilised with nitrogen and 45 Allofit acetabular components with a Durasul-polyethylene liner sterilised in ethylene oxide, both matched with an Alloclassic stem with a 28 mm modular femoral head. The prostheses were implanted between May 1999 and December 2001. The mean follow-up was for 66.3 months (60 to 92). The linear penetration of the femoral head was estimated at 6 weeks, at 6 and 12 months and annually thereafter from standardised digitised radiographs using image-analysis software. There was no loosening of any prosthetic component. There were no radiolucent lines or osteolysis. The mean rate of penetration calculated from regression analysis during the first five years was 38 microm/year (SD 2) for the Sulene group and 6 microm/year (SD 1) for the Durasul group (p = 0.00002). The rate of penetration of the Durasul group was 15.7% of that of the Sulene group.

Clinical and radiographic results and wear performance in different generations of a cementless porous-coated acetabular cup.

We compared clinical results and wear performance in two different generations of a cementless porous-coated cup, analysing the long-term results of 83 uncemented Harris-Galante I cups (32-mm femoral head) and 93 uncemented Harris-Galante II cups (28-mm femoral head). All polyethylene liners were gamma irradiated in air. Polyethylene linear wear was estimated using a software package. The minimum follow-up was 10 years. Nine Harris-Galante I cups and two Harris-Galante II cups were revised due to aseptic loosening or polyethylene problems. The mean femoral head penetration at 6 weeks after surgery was 0.15 +/- 0.05 mm for the Harris-Galante I cups and 0.12 +/- 0.03 for the Harris-Galante II cups (p < 0.001);but mean wear was 0.13 +/- 0.23 mm per year for the Harris-Galante I cups and 0.11 +/- 0.10 for the Harris-Galante II cups (p = 0.740). Most of the metallic shells in both groups showed stable fixation. The so-called second-generation cups had lower initial polyethylene wear that resulted in less polyethylene wear at the latest the follow-up, but the overall wear rate was similar in both groups despite the different femoral head sizes and the improved locking mechanism.

Long-term results of uncemented acetabular cups with an ACS polyethylene liner. a 14-16-year follow-up study.

We assessed the clinical and radiographic results of 40 porous-coated acetabular cups with an Acetabular Cup System polyethylene liner over a minimum 14-year follow-up. Femoral head penetration was estimated using a software package. Fifteen cups were revised, 11 due to polyethylene liner rupture. All cups but two were radiographically stable, and 11 hips showed acetabular osteolysis. The overall femoral head penetration rate in hips without liner fracture with reference to the early penetration point was 0.1188+/-0.070 mm per year. Polyethylene liner fractures were associated with higher early femoral head penetration (P<0.0001) and a vertical cup position (P=0.0016). The 14-year survival without cup revision for any reason was 63.9%, 71.8% with no ACS polyethylene liner fracture and 65.3% with no acetabular osteolysis. Most cups showed a good clinical outcome in general, but major Acetabular Cup System liner failure and osteolysis were frequent. Patients with the ACS cups still in place should be monitored closely.

Cemented femoral stems in patients with DDH.

Total hip arthroplasty is the procedure of choice for most adult patients with symptomatic arthrosis secondary to developmental dysplasia (DDH), but it requires complex reconstructive techniques, is usually performed in young patients, and has an increased risk of complications. THA is indicated in presence of severe pain and when osteotomy is contraindicated. The complexity of surgery is related to the degree of dysplasia. Anatomic abnormalities in the acetabulum and femur are the cause of the complexity and complications of this procedure. Acetabular bone deficiency requires reconstructive techniques before implanting the cup at the anatomic acetabular location, such as bone autograft augmentation, implanting the cup at higher level of the hip center and cup medialization. Femoral shortening and special cemented or uncemented stems are currently used to avoid intraoperative complications. While a cemented stem needs metaphyseal femoral shortening, subtrochanteric shortening requires a cementless stem. Because of these patients' age, alternative bearing surfaces, such as alumina-on-alumina couples are recommended when possible. Although the long-term results of total hip arthroplasty in DDH are inferior to those in a general population, the results show a high level of pain relief and functional improvement.

Porous-coated anatomic uncemented total hip arthroplasty. A 10-17-year follow-up.

A total of 91 PCA total hip arthroplasties were analysed with a mean follow-up of 13.5 years. Thirty-one cups and six stems were revised. If the patients excluded from the follow-up study are included (113 hips), the cumulative probability of having revision of any prosthetic component for any cause was 16.0% (0.1%-31.9%) at 14 years in the "best case" scenario. Thigh pain (17 hips) was correlated with unstable fixation. Radiographic loosening occurred in 21 cups and 12 stems. Cup loosening was related to acetabular polyethylene wear equal to or more than 2mm per year and also to cup size and thereby polyethylene thickness. Stem loosening was related to poor femoral canal filling. Fifty hips had femoral osteolysis which was related to polyethylene wear of more than 2 mm, poor femoral filling and unstable fixation. (Hip International 2005; 15: 78-84).

Internal fixation of displaced femoral neck fractures in patients older than 70 years.

INTRODUCTION: To analyse results and risk factors for osteosynthesis of displaced femoral neck fractures in patients older than 70 years. PATIENTS AND METHODS: From 1992 to 2000, 183 consecutive patients over 70 with displaced femoral neck fractures were treated by closed reduction and fixation with cannulated screws and followed up prospectively for two years. Pain at rest and pain with walking, return to previous functional and walking ability, and need for additional surgery were evaluated. RESULTS: Six patients died, while 149 were followed up for a minimum of two years: 82 (55%) were asymptomatic, 19 (12.8%) had mild pain, 39 (26.1%) required arthroplasty and 9 (6%) were too ill for further surgery. Poor quality reduction (p=0.008) and poor quality osteosynthesis (p= 0.064) were risk factors for failure. Fifty patients (33.6%) presented with non-union: 6/50 were asymptomatic, 34/50 required arthroplasty, and 10/50 were very ill. Ischaemic necrosis appeared in ten cases (6.7%) (five asymptomatic and five requiring arthroplasty). CONCLUSIONS: Reduction and fixation of displaced femoral neck fractures achieved good results in 68% of patients over 70, but re-operation became necessary in 32% of them; this made internal fixation advisable only for selected patients who were very active. The main risk factors were poor-quality reduction followed by poor osteosynthesis. (Hip International 2005; 15: 21-6).

The intramedullary elongation nail for femoral lengthening.

We have analysed the results of 24 femoral lengthenings in 23 patients operated on between 1993 and 2000, using a gradual elongation intramedullary nail (Albizzia). Of the 23 patients, 22 had femoral deficiency and one was of short stature. Their mean age was 16.9 years. Technical difficulties encountered during the procedure were mild or moderate in 18 femora and severe in six femora. Distraction was obtained by 15 ratchetings per day (1 mm/day). There were 18 excellent results although in two patients this was achieved after the development of a pseudarthrosis which required further surgery. There were four good and two fair results in which the lengthening obtained was at least 3 cm less than had been projected. The consolidation index was 35.2 days/cm. No patient had associated long-term stiffness of the knee. Femoral lengthening using an elongation nail gives good results and is a comfortable procedure.

Impacted morsellised allograft and cemented cup in acetabular revision surgery. A five to nine year follow-up study.

Seventy cemented cups associated with impacted morsellised allograft in revision surgery in hips with an acetabular bone defect greater than 30% (Paprosky Grades 3A and 3B) were analyzed. The mean follow-up was 6.8 years. One hip showed cup migration and was re-revised; this represents a total cumulative probability of re-revision of the cup of 1.4 2.8%. Radiolucent lines were uncommon: six cups showed radiolucent lines in DeLee and Charnley zone 1, five in zones 1 and 2, one in all three zones, while one hip showed migration.Although the frequent use of a metallic mesh makes graft remodeling difficult to evaluate, six hips showed minor and one major bone resorption. The mid-term results with impacted allograft and cemented all-polyethylene cups are favourable in acetabular revision surgery. (Hip International 2002; 12: 281-8).

The Harris-Galante total hip arthroplasty: a minimum 8-year follow-up study.

A total of 93 Harris-Galante Porous I (HGP- I) prostheses were analyzed with a mean follow-up of 10.2 years. Thigh pain (28 hips) correlated with unstable fixation (P<.005), female gender (P<.045), young age (P<.05), poor distal femoral fill (P<.002), subsidence (P<.0001), and osteolysis (P<.05). Thirteen stems and 6 metallic shell cups were revised. Kaplan-Meier analysis showed 13-year survival rates of 92.5% +/- 5.8% for the metallic shell cup, 79.7% +/- 13% for the HGP-I cup, and 76.3% +/- 14.0% for the stem. Five polyethylene liners were changed because of wear >1 mm. Radiographic loosening occurred in 8 cups. Radiographic bone ingrowth was present in 54 stems, stable fibrous fixation was present in 24 stems, and unstable fixation was present in 15 stems. The mean polyethylene wear was 0.17 mm/y. Eleven hips (11.8%) had acetabular osteolysis, and 24 (25.8%) had femoral osteolysis, the latter being more frequent in unstable stems (P<.007). The HGP-I metallic cup shows better clinical and radiographic results than the stem, which frequently is associated with pain, unstable fixation, and osteolysis. Excessive polyethylene wear is frequent.

Low-friction arthroplasty in patients younger than 40 years old: 20- to 25-year results.

A total of 67 low-friction arthroplasties were performed from 1971 through 1978 in patients <40 years old and followed an average of 21.7 years. There have been 33 cup loosenings and 17 stem loosenings. The average rate of wear of the cup was 0.12 mm/y for the entire series and 0.16 mm/y for the revised cups. Although the preoperative diagnosis leading to low-friction arthroplasty commonly reflected some deficiency in bone structure, particularly in the acetabulum, there were no primary osteoarthrosis cases. The femoral stem proved to be durable, but acetabular cups gave poorer results in younger patients than in older patients. The 2 major factors limiting the longevity of the cemented cup were acetabular bone quality and wear.

Loosening of the cup after low-friction arthroplasty in patients with acetabular protrusion. The importance of the position of the cup.

Between 1972 and 1990, we performed 168 primary low-friction arthroplasties in 125 patients with acetabular protrusion. Twelve hips were lost to follow-up within eight years and eight which became infected were excluded from the final study. Of the 148 hips remaining, 62 with a mild protrusion were classified as group 1, 54 with moderate or severe protrusion as group 2 and, after 1985, 32 with moderate and severe protrusion which required bone grafts as group 3. The mean follow-up was 18.3 years (3 to 24) for group 1, 17.4 years (8 to 22) for group 2 and ten years (8 to 13) for group 3. There were 31 revisions of the cup, 12 in group 1 and 19 in group 2. According to the Kaplan-Meier analysis the overall rates at 20 years were 21 +/-10.79% in group 1 and 37 +/- 11.90% in group 2. There have been 43 radiological loosenings: 22 in group 1, 21 in group 2 and none so far in group 3, at ten years. The overall loosening rates at 20 years were 42 +/-14.76% in group 1 and 49 +/- 19.50% in group 2. The grafts were well incorporated in all group-3 hips, and the bone structure appeared normal after one year. The distance between the centre of the head of the femoral prosthesis and the approximate true centre of the femoral head was less in group 3 than in groups 1 and 2 (p < 0.01). According to the Cox proportional-hazards regression this was the single most important factor in loosening of the cup (odds ratio 1.11; 95% CI 1.05 to 1.18/mm). Better results were obtained in moderate and severe protrusions reconstructed with bone grafting than in hips with mild protrusion which were not grafted.