Introduction: Periprosthetic fractures have long been recognized as one of the major complications after hip resurfacing arthroplasty. Both biomechanical factors and pathological changes of bone tissue might hypothetically influence its occurrence. We analyzed retrieved femoral remnants to identify possibly different fracture modes.

Material and Methods: 83 hips revised for periprosthetic fracture (134.5 days in situ±159.2) were analyzed macroscopically, contact radiographically and histologically. Most cases (80.7%) were treated for advanced stages of osteoarthritis. Hips with preoperative femoral head necrosis were not included. 49 (59.0%) patients were men (57.8 years old±8.5) and 34 (41.0%) women (55.1 years old±10.0; p=.3445). Occurrence of reactive changes and of avascular necrosis in addition to amount of osteonecrosis were used as the major histological criteria for classification of the fracture as acute biomechanical, acute postnecrotic or chronic.

Statistical analyses were performed using statistical software. Probability of Type I error was set to 5% (alpha=0.05).

Results: 37 (44.6%) femoral neck fractures (83.9 days±87.7) occurred earlier than the remaining 46 (55.4%) head fractures (174.1 days±89.7; p=.0129). 50(60.2%) remnants revealed complete osteonecrosis and were thus classified as acute postnecrotic fractures, 29 (34.9%) chronic fractures were characterized by finding of pseudoarthrosis or preformed callus and the remaining 4 (4.8%) were classified as acute mechanic. Acute mechanic fractures (17.5 days±8.0) failed earlier than both acute postnecrotic (146.3 days±181.7; p=.0049) and chronic (130.8 days±120.6; p=.0017) fractures.

Osteonecrosis was found in 81 (97.6%) hips revised after fracture (p< .0001). The vertical size of avascular necrosis in hips after acute postnecrotic fracture (21.1mm±8.5) was bigger (p< .0001) than in both chronic (7.3mm±7.3) and acute mechanic (0.9 mm±1.2) fractures.

Even though 33 (66.0%) of 50 patients with acute postnecrotic fracture were men (p=.0237), no significant differences between males and females were found with respect to age of patients (p=.3445) or duration of prosthesis implantation (p=.1232).

Conclusion: We analyzed hips revised for periprosthetic fracture after the resurfacing arthroplasty. Three distinct fracture modes of this complication could have been identified morphologically. Osteonecrosis secondary to the hip resurfacing arthroplasty appeared to be causative for more than a half of all fractures in present cohort. Mechanical and biomechanical factors related to the procedure might have possibly influenced the occurrence of both postnecrotic fractures and cases with vital reactive changes of tissues neighbouring the fracture line.

The proposed classification may help to understand causes of periprosthetic fractures after hip resurfacing arthroplasty.

Introduction: Metal-on-metal (MoM) articulations for THA are used successfully from CoCr-alloys. Low or high carbon hydride metals contain less or more than 0.2% carbon in the alloy. The systems show encouraging clinical results and lower rates of aseptic loosening in midterm results. Hypersensitivity reactions to high carbide MoM articulations were reported. The immune response is characterized by a perivascular T-/B-lymphocyte infiltration of the capsular tissue around the hip replacement. The present study examines if lymphocytic reactions are present in low carbide MoM THA and if distinct cytokines are released to joint fluids. Retrieval tissues from 28 patients were used. Joint fluids were aspirated at the time of surgery.

Materials and Methods: Tissues were collected from 25 patients undergoing 26 aseptic revisions of MoM THA (CoCrMo, Sikomet^®, Plus Orthopaedics). The patients had following symptoms: Hip and femoral pain; recurrent dislocation and clicking noises. 8 patients had osteolysis, 12 patients showed a metallosis. The peripros-thetic tissues were examined by standard histology and immunohistochemistry. Joint fluids were frozen at the time of surgery. The control groups were patients with osteoarthritis of the hip (n=10), revisions from Al2O3-UHMWPE articulations (n=6), revisions of MoM with hypersensitivity reaction (n=18), and MoM without hypersensitivity reactions (n=8). The fluids were analyzed for various Interleukins, Il-1 receptor antagonist, G-CSF, GM-CSF, IFN gamma, MIP-1ß, and TNF-α.

Results: 18 out of 26 cases showed diffuse and follicular lymphocyte infiltrations in the revision tissues. Perivas-cular T- and B-lymphocytes and few macrophages were also seen. In low and excessive metallosis no lymphocytes were observed. The tissue response in low carbide MoM is similar to high carbide MoM. Analysis of the cytokine profile in the joint fluids showed markers of osteoclast activation (Il-6 and −10) in all MoM articulations. TNF-α increase was increased in all loosening groups but was further increased in MoM. Il-5, IFN gamma, MIP-1ß, and GM-CSF were increased in all fluids from loosening cases but were further increased in MoM with lymphocyte activation.

Discussion: Activation of lymphocytes in failed MoM THA’s is not necessarily related to high carbide MoM. Hypersensitivity also occurred in low carbide MoM THA. The cytokine profiles in the joint fluids showed distinct characteristics. Il-6 and Il-10, markers of osteo-clast activation, were elevated in all cases of bone loss and osteolysis. The increase in TNF-α may account for a regulation of the OPG/RANKL system TNF-a which can induce osteolysis. The elevated levels of Il-5, IFN gamma, MIP-1ß, and GM-CSF in MoM failures with hypersensitivity represent markers of chemotaxis and lymphocyte activation may account for index markers of hypersensitivity reaction.

Introduction: Rheumatoid arthritis often leads to severe destruction of the glenohumeral joint including synovitis and inflammation induced alterations of the rotator cuff. Cup arthroplasty, or surface replacement of the shoulder was introduced in the 1980s. The aim of this study was to confirm or withdraw the very promising results of the DUROM-Cup surface replacement for patients with rheumatoid arthritis.

Patients an Methods: From 1997 to 2000 a cohort of 42 DUROM-Cup hemiprotheses were implanted in 35 patients. The patients were evaluated preoperatively and after 3,12 and more than 60 month postoperatively. 7 patients were lost to follow up. A total of 35 DUROM-Cups (29 patients) could be examined prospectively after an average follow up period of 73.1 (+/− 12.1) month (Average age 61.4y, female n=21, male n=68). Rotator cuff defects were classified intraoperatively.

Results: Three revisions occured: One due to a too large implant, one due to glenoid erosion and one due to loosening of the implant. The constant score increased from preoperatively 20.8 points to 64.3 points at a mean follow up of 73.1 month. No differences were seen in patients with massive cuff tears. In these cases the cup was implanted in a more valgic position, so that articulation with the acromion could be achieved. The radiographic results did not show any changing of the parameters for the position of the cup. No further endo-prosthetic loosening was observed. The proximal migration increased in 66% and the glenoid depht increased in 37% of the cups.

Discussion: The results of the cemented DUROM-Cup surface replacement for patients with advanced rheumatoid arthritis of the shoulder are very encouraging, especially in patients with massive tearing of the rotator cuff. The advantages of cup arthroplasty are to be found in the reduced level of invasive surgery and the simpler technique with bone saving fixation. In the event of failure of the implant good further treatment options for salvage procedures remain.

Background: Successful total knee arthroplasty requires component alignment according to the mechanical axes and restoration of ideal knee kinematics. This requires adequate ligament balancing, stable tibia-femoral and patello-femoral joints, and a non-restricted range of motion.

We developed a computer assisted total knee arthroplasty system to help the surgeon achieving more intra-operative accuracy.

Material and methods: An OPTOTRAK camera is used to track relative motions between femur, tibia, and instruments. In contrast to other systems we avoid fixation of reference bases onto acetabulum and foot. The surgeon generates a representation of the patient’s anatomy using the technique of “surgeon defined anatomy”. Based on recorded landmarks the system calculates the femoral and tibial mechanical axes, the position of the knee joint line, the level of the defects on femoral and tibial side, the anatomically best fitting femoral component size, the femoral ventral level, and the natural tibial rotation. These values enable an initial planning situation, which features alignment of the tibial and femoral distal resection planes according to the mechanical axes as well as the definition of the anterior and posterior femoral resection planes with respect to the ventral cortex and the prosthesis design. To consider soft-tissue behaviour the surgeon loads both collateral ligaments in extension and flexion, a

Results: During a clinical study we performed thirteen total knee arthroplasties. Postoperatively passive extension was 0.8-4.2° (mean 1.9°) in the coronal plane and 0.2-3.9° (mean 1.8°) in the sagittal plane. Varus-valgus instability was 7.2°. The results of the subsequent patients of this ongoing study will be available during the conference.

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.