Aims

Revision total hip arthroplasty in patients with Vancouver type B3 fractures with Paprosky type IIIA, IIIB, and IV femoral defects are difficult to treat. One option for Paprovsky type IIIB and IV defects involves modular cementless, tapered, revision femoral components in conjunction with distal interlocking screws. The aim of this study was to analyze the rate of reoperations and complications and union of the fracture, subsidence of the stem, mortality, and the clinical outcomes in these patients.

ZrN-multilayer coating is clinically well established in total knee arthroplasty [1-3] and has demonstrated significant reduction in polyethylene wear and metal ion release [4,5].

The goal of our study was to analyze the biotribological behaviour of the ZrN-multilayer coating on a polished cobalt-chromium cemented hip stem.

CoCr28Mo6 alloy hip stems with ZrN-multilayer coating (CoreHip®AS) were tested versus an un-coated version. In a worst-case-scenario the stems with ceramic heads have been tested in bovine serum in a severe cement interface debonding condition under a cyclic load of 3,875 N for 15 million cycles. After 1, 3, 5, 10 & 15 million cycles the surface texture was analysed by scanning-electron-microscopy (SEM) and energy-dispersive x-ray (EDX). Metal ion concentration of Co,Cr,Mo was measured by inductively coupled plasma mass spectroscopy (ICP-MS) after each test interval.

Based on SEM/EDX analysis, it has been demonstrated that the ZrN-multilayer coating keeps his integrity over 15 million cycles of severe stem cemented interface debonding without any exposure of the CoCr28Mo6 substrate.

The ZrN-multilayer coated polished cobalt-chromium cemented hip stem has shown a reduction of Co & Cr metal ion release by two orders of a magnitude, even under severe stem debonding and high interface micro-motion conditions.

ZrN-multilayer coating on polished cobalt-chromium cemented hip stems might be a suitable option for further minimisation of Co & Cr metal ion release in total hip arthroplasty. Clinical evidence has to be proven during the next years.

Aims

Biopsy of the periprosthetic tissue is an important diagnostic tool for prosthetic joint infection (PJI) as it enables the detection of the responsible microorganism with its sensitivity to antibiotics. We aimed to investigate how often the bacteria identified in the tissue analysis differed between samples obtained from preoperative biopsy and intraoperative revision surgery in cases of late PJI; and whether there was a therapeutic consequence.

Introduction

Metal ion and particle release, particularly cobalt, has become an important subject in total hip arthroplasty, as it has shown to induce metal hypersensitivity, adverse local tissue reactions and systemic ion related diseases. The purpose of the following study was compare the ion release barrier function of a zirconium nitride (ZrN) multilayer coated hip stem for cemented use, designed for patients with metal ion hypersensitivity, against its uncoated version in a test configuration simulating the worst case scenario of a severely debonded hip stem. The ZrN multilayer coating is applied on a CoCrMo hip stem and consists of a thin adhesive chromium layer, five alternating intermediate layers out of chromium nitride (CrN) and chromium carbonitride (CrCN) and a final zirconium nitride (ZrN) shielding layer [1].

Aims

To evaluate the hypothesis that failed osteosynthesis of periprosthetic Vancouver type B1 fractures can be treated successfully with stem revision using a transfemoral approach and a cementless, modular, tapered revision stem with reproducible rates of fracture healing, stability of the revision stem, and clinically good results.

The stem and the rasp for cemented arthroplasty are typically designed to obtain a cement mantle 2–5 mm thick. However, sometimes a line-to-line cementation is preferred, where the femoral cavity is prepared with the same dimension as the actual stem. There are contrasting reports [1,2] about the suitability of this technique to withstand the long-term fatigue loads. While the theoretical geometry allows no space for the cement, a sort of cement mantle is formed as the cement penetrates in the spongy bone. The scopes of this study were: 1) developing a dedicated in vitro method to test line-to-line cementation; 2) assessing if a short, polished hip stem designed for a standard cementation can be safely cemented line-to-line.

In order to perform long-term mechanical in vitro tests, composite bones must be used, as cadaveric bones cannot withstand millions of loading cycles [3]. For this study, the Sawbones Mod. 3406-4 were chosen: they feature an open-cell polyurethane core simulating low-density spongy bone. Post-implantation x-rays confirmed that a relevant cement-bone interdigitation was obtained. Four femurs were prepared with a CoreHip (Aesculap) with regular cement mantle (Regular). Another 4 femurs were rasped to the same rasp size, and implanted with line-to-line cementation with a larger stem (Line-to-line). The implanted femurs were subjected to an accelerated test derived from a validated protocol [3] which replicates the most demanding motor tasks of 24 years of patient activity. Implant elastic micromotions and permanent migrations were measured throughout the test. The implants were then sectioned and treated with dye penetrants to highlight the cement cracks.

Elastic and permanent motions did not show any loosening trend, and never exceeded few micrometers. As expected, some damage was visible in the cement mantles after test completion, for both types of implantation (similar to retrieved cement mantles surrounding stable implants [3]. The cement damage was similar in all specimens. No sign of major disruption was visible, neither within the Regular nor in the Line-to-line specimens: in fact, the cracks were limited in length, did not seem to cross the entire mantle thickness, and did not result in any loose cement fragments. The cracks in the line-to-line implants showed the same position and distribution compared to those found in the regular implants, but were slightly longer in some specimens.

This in vitro study confirmed the feasibility of simulating line-to-line cementation in vitro. Our results suggest that a stem designed for a regular cement mantle could induce slightly more damage when implanted line-to-line, but no significant trend toward loosening.

We report our experience of revision total hip replacement (THR) using the Revitan curved modular titanium fluted revision stem in patients with a full spectrum of proximal femoral defects. A total of 112 patients (116 revisions) with a mean age of 73.4 years (39 to 90) were included in the study. The mean follow-up was 7.5 years (5.3 to 9.1). A total of 12 patients (12 hips) died but their data were included in the survival analysis, and four patients (4 hips) were lost to follow-up. The clinical outcome, proximal bone regeneration and subsidence were assessed for 101 hips.

The mean Harris Hip Score was 88.2 (45.8 to 100) after five years and there was an increase of the mean Barnett and Nordin-Score, a measure of the proximal bone regeneration, of 20.8 (-3.1 to 52.7). Five stems had to be revised (4.3%), three (2.9%) showed subsidence, five (4.3%) a dislocation and two of 85 aseptic revisions (2.3%) a periprosthetic infection.

At the latest follow-up, the survival with revision of the stem as the endpoint was 95.7% (95% confidence interval 91.9% to 99.4%) and with aseptic loosening as the endpoint, was 100%. Peri-prosthetic fractures were not observed.

We report excellent results with respect to subsidence, the risk of fracture, and loosening after femoral revision using a modular curved revision stem with distal cone-in-cone fixation. A successful outcome depends on careful pre-operative planning and the use of a transfemoral approach when the anatomy is distorted or a fracture is imminent, or residual cement or a partially-secured existing stem cannot be removed. The shortest appropriate stem should, in our opinion, be used and secured with > 3 cm fixation at the femoral isthmus, and distal interlocking screws should be used for additional stability when this goal cannot be realised.

Cite this article: Bone Joint J 2014;96-B:889–95.

In acetabular revision press-fit cups usually are used in smaller defects and contact to the host bone should be more than 50 %. Due to the thin wall thickness and the surface design the cementless press-fit cup Allofit S has a specific characteristic during implantation. Therefore this cup was used for revision with greater acetabular defects and analysed in a prospective study. The press-fit in these cases was 4 mm and additional 2 or 3 screws into the Os ilium were used.

64 cups were were followed prospectively for 38.3 months with a minimum of 24 months and examined clinically (Harris-Hip-Score) and radiographically for migration (Method of Nunn et al.) and loosening (Method of Delee and Charnley). Corresponding to Nunn et al. and Blum et al., cup migration was defined to be a change of position greater than 3 mm or referring to Cordero-Ampuero et al. and Dickob et al. a change of inclination greater than 5 degrees. There were 25 revisions of the cup and 39 complete exchanges of the prosthesis due to 54 aseptic and 10 septic loosenings (two-step revision with spacer and cementless reimplantation). There were acetabular defects of type Paprosky 2A in 12 cases, of type 2B in 15 cases, type 2C in 19 cases, type 3A in 16 cases and type 3 B in 2 cases. The average age of the patients was 70.9 ± 8.9 years.

The Harris-Hip-Score increased from 45.4 ± 14.9 points preoperatively to 81.8 ± 17.5 points one year and 82.3 ± 17.1 points two years postoperative. There was no loosing or significant migration of the cups.

The Allofit S press-fit cup shows good result in cup revisions with greater acetabular defects when using a press-fit of 4 mm and additional 2 or 3 screws. In these cases it seems to be a good and cheeper alternative to specific implants like trabecular metal cups.

We analysed the serum C-reactive protein level, synovial fluid obtained by joint aspiration and five synovial biopsies from 145 knee replacements prior to revision to assess the value of these parameters in diagnosing late peri-prosthetic infection. Five further synovial biopsies were used for histological analysis. Samples were also obtained during the revision and incubated and analysed in an identical manner for 14 days.

A total of 40 total knee replacements were found to be infected (prevalence 27.6%). The aspiration technique had a sensitivity of 72.5% (95% confidence interval (CI) 58.7 to 86.3), a specificity of 95.2% (95% CI 91.2 to 99.2), a positive predictive value of 85.3% (95% CI 73.4 to 100), a negative predictive value of 90.1% (95% CI 84.5 to 95.7) and an accuracy of 89%. The biopsy technique had a sensitivity of 100%, a specificity of 98.1% (95% CI 95.5 to 100), a positive predictive value of 95.2% (95% CI 88.8 to 100), a negative predictive value of 100% and an accuracy of 98.6%. C-reactive protein with a cut-off-point of 13.5 mg/l had a sensitivity of 72.5% (95% CI 58.7 to 86.3), a specificity of 80.9% (95% CI 73.4 to 88.4), a positive predictive value of 59.2% (95% CI 45.4 to 73.0), a negative predictive value of 88.5% (95% 81.0 to 96.0 CI) and an accuracy of 78.1%.

We found that biopsy was superior to joint aspiration and C-reactive protein in the diagnosis of late peri-prosthetic infection of total knee replacements.

Aim: The aim of this prospective study was to analyse the rate of sinking and the clinical results of the new cementless modular revision stem Revitan curved concerning the length of fixation of the implant and the technique of implantation (endofemoral compared with transfemoral).

Material and Methods: 51 cementless modular curved revision stems (Revitan curved) were implanted 17 times endofemoral and 34 times transfemoral. All operations were performed by the first author with 24 times a total exchange of the hip implants and 27 times an exchange of the stem. Patients were followed every 3 months in the first postoperative year and then every 6 months. Because sinking of a cementless implant occurs during the first postoperative year the minimum follow-up was 12 months (average follow-up was 22.5 + −12.6 months). Patients were evaluated clinically using the Harris Hip-Score and length of fixation of the implant as well as implant sinking was evaluated radiographically.

Results: The Harris Hip-Score increased from 45.7 preoperatively to 86.7 twelve months postoperative in endofemoral implanted stems and from 41.6 preoperatively to 81.2 twelve months postoperative in transfemoral implanted stems. The patients with transfemoral implanted stems had a significant higher amount of limping and positive Trendelenburg sign after the operation. With time the percentage decreased and reached nearly the same level as in patients with endofemoral implanted stems. 2 endofemoral and 1 transfemoral (with a fixation length of less than 3 cm) implanted stems showed a sinking of 5 mm. 2 transfemoral implanted stems had to be revised because of aseptic loosening. In both stems the fixation length was less than 3 cm in the first revision due to operative technical reasons.

Conclusion: The curved cementless revision stem Revitan shows encouraging results using the endofemoral and transfemoral technique. In transfemoral implantation a secure fixation can be reached with a fixation length of more than 3 cm (which is less than the usually recommended fixation length of 4 to 6 cm for cementless revision stems). Transfemoral implanted stems need a longer time of rehabilitation than endofemoral implanted stems

Aim of study

The thrust plate prosthesis is an implantat with metaphyseal fixation at the proximal femur, which leaves the diaphyseal bone untouched. Therefore this implant preferably is employed in younger patients. It is dependent on a good bone quality in the proximal femur. Because bone quality is reduced in patients with polyarthritis, this kind of endoprosthesis may have a higher failer rate than conventional stemmed endoprostheses in these patients. Therefore in patients with polyarthritis even short- end midterm results of the thrust plate prosthesis should be analyzed.

Material and Methods

47 thrust plate prostheses were implanted in 42 patients with polyarthritis (29 with rheumatoid arthritis, 6 with juvenile chronic arthritis and 7 patients with spondarthritis) and followed prospectively. The average age at the operation was 40. 8 ± 10. 7 years. Each patient was clinically and radiologically examined preoperative, 3 and 6 months after the operation and at the end of each postoperative year. The mean follow-up was 26. 1 ± 10. 7 months. The clinical findings were evaluated using the Harris-Hip-Score. Radiologically 8 different zones at the thrust plate prosthesis were analyzed for radiolucencies.

Results

During the first year the Harris-Hip-Score rose continuously from the preoperative average of 42. 4 ± 6. 5 points to 78. 8 ± 10. 3 points 3 months postoperatively, 82. 3 ± 9. 8 points 6 months postoperatively, and 86. 8 ± 10. 1 points 1 year after the operation. The following examinations showed Harris-Hip-Scores at the same level. 5 patients (5 joints, 10. 6%) had to undergo a revision of the thrust plate prosthesis due to aseptic loosening in 3 cases and septic loosening in 2 cases. 6 prostheses (12. 6 %) showed radiolucencies, mostly below the thrust plate in zone 1 and 2. 2 of these prostheses were certainly radiologically loose which raised the failure rate to 7 of 47 (14. 8 %).

Conclusion

The thrust plate prosthesis improves function and pain in patients with polyarthritis to a satisfactory degree. Concerning the failure rate this type seems to yield slightly worse results than cementless stemmed endoprostheses in the same patient group. Due to the preservation of the diaphysial bone of the femur and the possibility of an unproblematic change to a stemmed endoprosthesis the thrust plate prosthesis keeps its indication in younger patients with polyarthritis.

Survivorship analysis was performed on 479 Link V-Type cementless threaded acetabular cups on 310 cases with inflammatory arthritis, 138 cases with osteoarthritis and 31 cases with dysplastic hip. The average follow-up was 8. 6 ± 3. 2 years. The same analysis was performed on a modified cup with a smaller primary coil (type ”Bad Bramstedt”). This analysis had a mean follow-up period of 4. 5 ± 0. 7 years in 110 cases, including 49 with inflammatory arthritis, 49 with osteoarthritis and 12 with dysplastic hip. In a second approach 264 Link V-cups with a mean follow-up period of 8. 2 ± 2. 7 years and 59 modified cups with a mean follow-up period of 4. 6 ± 0. 7 years were radiologically examined for radiolucent lines according to Delee and Charnley and cup migration with regard to the method of Nunn et al.

The cumulative survival rate for the former Link V-Type acetabular cup was 94. 5% after 5 years, 88. 1% after 10 years and 71. 2% after 15 years. The ”Bad Bramstedt” cup showed a 5 year survivorship rate of 97. 9%. Migration greater than 3 mm or tilting of the cup greater than 5 degrees was seen in 73% of the former type and in 39% of the modified cup. Radiolucent lines greater than 2 mm and detectable in two zones appeared in 6. 4% of the former Link V-Type and in 1. 7% of the ”Bad Bramstedt” cup design. Significant influence on cup migration was found in primary implant positioning and time elapsed. Due to the high rates of migration of the two implant designs and the frequent late aseptic loosening of the former Link V-Type acetabular component these two types of threaded cups were abandoned in favor of cementless press-fit cups.

Introduction

Synovectomy in children with juvenile rheumatoid arthritis (JRA) and psoriatic arthritis (PSA) is still subject of controversial discussion. Our results of arthroscopic synovectomy of the knee in children with chronic inflammatory joint disease are presented.

Material

From 1989–1997 27 synovectomies were performed in 27 children with inflammatory arthritis (15 JRA, 12 PSA). Average age at surgery was 12. 5 y (2. 9–17. 8 y). Mean follow-up was 4. 9 years.

Methods

Onset of disease and conservative therapy was documented. Each patient was physically and radiologically examined preoperatively and 24 children postoperatively (mean follow-up 4. 9 years). For arthroscopic shaver-assisted synovectomy of the knee we used minimum 4 portals and normally 6 portals (2 anterior, 2 suprapatellar and 2 posterior portals). In addition to the physical examination we used a special clinical score (Laurin 1974). We compared the pre- and postoperative limits of active and passive knee movement. We performed sonographs and radiographs of the infected joint. Radiography was classified following the Larsen-Scale. Patient and parents gave their opinion whether the operation was successful. Before surgery all children had intensive drug and physical therapy for 8–62 months (42 month). In the course of conservative treatment, knees had local joint treatment with triamcinolonhex-acetomid (THA), normally for three times before surgery. Preoperative X-rays showed Larsen stage I in 3 knee joints and Larsen stage 0 in the other knees.

Results

In 85% of the children, we found good or excellent surgical outcome. 2 joints achieved fair and 2 joints poor outcome. Concerning subjective outcome 22 (82%) children had been very satisfied (56%) or satisfied (26%). 25 of the children’s parents would agree in the same surgical procedure again. In 6 knee joints we found recurrent synovitis. 2 of these knee joints were reoperated (30 and 22 month postoperatively with satisfying result), the other 4 joints were treated with THA i. a.. The 2 reoperations were regarded as poor result. We had no postoperative complications and the normal hospitalisation was 15 days. Prior to surgery, 12 knee joints had an average deficit of active knee extension of 10° (5–20°). Postoperatively, no extension deficit was found anymore in 25 of the knees. Compared to the contralateral knees, a flexion deficit of 10° (5–15°) was obtained postoperatively. At sonography, no joint effusion could be revealed. Postoperative X-rays showed no progression in Larsen stage. Outcome in children with oligoarthritis was better than in those with polyarthritic disease.

Discussion

Early arthroscopic synovectomy of the knee in children with chronic inflammatory joint disease is, in case of failure of conservative treatment, a useful method of treatment. We propose early synovectomy of the knee joint as an essential part of the treatment scheme for children with inflammatory joint disease.

Aim of study

The concept of a new developed cup arthroplasty (Durom-Cup) is the replacement of the destroyed joint surface with minimal bone resection. In cases of additional cuff arthropathy the cup can be placed in a more valgic position to articulate with the glenoid and the acromion. The aim of this prospective study was to evaluate the results of this surface replacement as a hemiarthroplasty in rheumatoid arthritis with and without cuff arthropathy.

Material and Methods

35 Durom-Cups of 29 patients (23 woman, 6 men) with rheumatoid arthritis were evaluated preoperatively and every 3 months postoperatively. 7 of these shoulders additionally had cuff arthropathy. The average age was 61. 6 ± 11. 8 years and the average follow-up 33. 4 ± 11. 8 months. The Constant-Score and SAS-function-Score were used and the cups were examined radiologically.

Results

In rheumatic shoulders without cuff arthropathy the Constant-Score increased from 20. 6 ± 9. 5 points preoperatively to 47. 1 ± 14. 8 points 3 months postoperatively, to 47. 4 ± 13. 7 points 6 months, and to 56. 3 ± 8. 8 points 9 months postoperatively. During further follow-up it increased slightly and was 59. 5 ± 10. 1 points 12 months, 61. 8 ± 11. 3 points 18 months and 64. 6 ± 14. 8 points 24 months postoperatively. In shoulders with cuff arthropathy the Constant-Score increased from 17. 6 ± 8. 2 points preoperatively to 45. 0 ± 6. 4 points 3 months postoperatively, to 45. 5 ± 8. 5 points 6 months, and to 51. 5 ± 838 points 9 months postoperatively. At this level the Constant-Score stayed during further follow-up and was 54. 1 ± 10. 5 points 12 months, 56. 3 ± 9. 8 points 18 months, and 56. 1 ± 11. 6 points 24 months postoperatively. No complication, component loosening, or changes of cup position were observed.

Conclusion

The results of the Durom-Cup are encouraging. In shoulders with additional cuff arthropathy the limited goal criteria were reached always. Therefore cup arthroplasty is a good alternative other kinds of shoulder endoprostheses in rheumatic shoulders with and without cuff arthropathy.

The aim of this study was to analyse the long-term results of a cementless conical threaded cup with elevated inlay-rim, without bone grafting in joint replacement of dysplastic compared to non-dysplastic hips, and concerning the survival rate and the rate of cup migration.

Most techniques of joint replacement of dysplastic hips contain bone grafting with more or less large-scale procedures. Without bone grafting, medialisation of the cup is often necessary. The conical threaded Link-V cup has the opportunity of stabilising the joint by using a polyethylene inlay with an elevated rim so that implantation in high angles of flexion and anteversion is possible. This is a technically easy procedure in dysplastic hips, but higher rates of loosening and cup migration are possible.

A cementless conical threaded cup (Link V) with elevated inlay-rim was followed in 36 dysplastic hips (DH) and 167 non-dysplastic osteoarthritic hips (OA) over a minimum follow-up of five years. Mean follow-up in DH-hips was 8.4 2.3 years and in OA-patients 8.6 3.2 years. Survival analysis was performed and cup migration was radiographically analysed using the method of Nunn et al.

The 10-year survival rate of the cup was 87% in DHhips compared to 92% in OA-hips. Luxation occurred in three OA-joints and none in DH-hips. Radiological cup migration was seen in 75% of DH-hips and in 70% of OA-joints. A change of the angle of flexion (mostly decrease) of more than two degrees was found in 50% of DH-hips and in 72% of OA-joints. There was vertical migration of more than 2 mm in 75% of DH-hips and in 70% of OA-hips, and a horizontal migration of more than 2 mm in 45% of DH-joints and in 40% of OA-hips. A radiolucent line of minimum 2 mm was seen in one case of each group.

Using a cementless threaded cup with elevated inlayrim is a practicable and technically easy procedure for treatment of destroyed dysplastic hips. Although cup migration is frequent in dysplastic and non-dysplastic hips, failure-rate is still acceptable but tends to be higher in dysplastic than in non-dysplastic hips.

We evaluated histologically samples of synovial tissue from the knees of 50 patients with rheumatoid arthritis (RA). The samples were taken during revision for aseptic loosening. The findings were compared with those in 64 knees with osteoarthritis (OA) and aseptic loosening and in 18 knees with RA without loosening. The last group had been revised because of failure of the inlay or the coupling system of a constrained prosthesis. All the patients had had a total ventral synovectomy before implantation of the primary prosthesis.

In all three groups a foreign-body reaction and lymphocellular infiltration were seen in more than 80% of the tissue samples. Deposits of fibrin were observed in about one-third to one-half of the knees in all groups. Typical signs of the reactivation of RA such as rheumatoid necrosis and/or proliferation of synovial stromal cells were found in 26% of knees with RA and loosening, but not in those with OA and loosening and in those with RA without loosening.

Our findings show that reactivation of rheumatoid synovitis occurs after total knee replacement and may be a cofactor in aseptic loosening in patients with RA.