INTRODUCTION

The lifetime of UHMWPE implants may be limited by wear and oxidative degeneration. Wear produced particles are in general biologically active, and may induce osteolysis. As threshold of PE wear rate below which osteolysis is rarely observed is postulated to be less tahn 0.1 mm per year. Moreover, PE delamination and breakage are consequences of the embrittlement of the PE due to oxidation. Both demonstrate, that improving the clinical behaviour of UHMWPE means reduction of wear particles. The first can be achieved by cross-linking the second by the anti-oxidative stabiliser vitamin E. The highly cross-linked PE vitamys ® used for the isoelastic monobloc cup RM Pressfit (Mathys AG Bettlach, Bettlach, Switzerland) is mixed with 0.1% of synthetic vitamin E and is the first and only highly cross-linked PE used in total hip replacement that meets all requirements for the best grade UHMWPE in yield strength, ultimate tensile strength and elongation at break.

Total knee arthroplasty (TKA) disturbs patellar blood flow, an unintended accompaniment to TKA that may be a cause for postoperative anterior knee pain. We compared patellar blood flow before and after medial parapatellar arthrotomy to pre- and postoperative anterior knee pain scores to ascertain whether disrupted patellar blood flow correlates with anterior knee pain following TKA. Blood flow measurements were performed at full extension and at 30°, 60°, 90° and 110° of flexion prior to and after medial arthrotomy in 50 patients (21 male, 29 female; mean age 73.1±8.6 years) undergoing TKA. Anterior knee pain was assessed using the pain intensity numeric rating scale. A significant decrease in blood flow was detected at 60°, 90°, and 110° of flexion (p values: 0.00314,< 0.0001,< 0.0001 respectively). The medial arthrotomy did not have a statistically significant influence on patellar blood flow in the Students’ t-test (margin of significance p& #61603;0.05) Nineteen patients exhibited an average 14% (range 1%–54%) increase in patellar blood perfusion at knee flexions of 90° and 110° after medial arthrotomy (p value: 0.32) Prior to TKA, 16 of the 50 patients (32%) complained of anterior knee pain (average NRS 7.12, range 5–10). At 6-month follow up, 4 of the 16 patients (25%) complained of moderate anterior pain (average NRS 5.7, range 5–6), while 8 of 16 (50%) patients reported discomfort (average NRS 3.5, range 2–4) around the patella. No statistically significant correlation was found between intraoperative findings on patellar blood flow and the presence of anterior knee pain

Introduction: Ruptured anterior cruciate ligaments (ACL) are generally thought not to heal after treatment so that the ligament must be replaced by a graft. We developed and evaluated a surgical technique that restores knee stability using the self-healing capacity of the ruptured ACL.

Methods: The ACL was cut close to the femoral insertion in 14 sheep. The contralateral, nonoperated side served as the control. After microfracturing at the femoral foot print, the ACL was stabilized using the dynamic intraligamentary stabilization (DIS) technique. A strong intraligamentary suture was attached on the femoral side with a button and on the tibial side by means of an intraosseous spring-loaded screw with a preload of 85 N. In 7 of 14 sheep the ruptured ligament was covered with a collagen membrane. The joint was not immobilized postoperatively. Histological evaluation, magnetic resonance imaging (MRI) and biomechanical testing were performed after 3 months.

Results: Three days postoperative all animals showed no lameness and regularly used the operated leg. Macroscopically, all repaired ACLs appeared healed. Histological and MRI examinations confirmed the healing response of the ACL after DIS. The collagen membrane exhibited a more hypertrophic scare tissue reaction. Biomechanical testing showed an average increase of the operated anterior drawer 2.4 mm (range 0 mm – 4.5 mm) greater than on the control side. No lesions of the meniscus and cartilage were detected.

Conclusions: A ruptured ACL has the biological potential to heal after DIS in a sheep model. The surgical technique achieved a stable knee joint with free range of motion and full weight bearing during the healing period without signs of osteoarthritis or other intraarticular damage at follow up.

Purpose: The purpose of this study was to examine the arthroscopy findings in the hips of patient with persistent pain after surgical hip dislocation for femoroacetabular impingement syndrome.

Type of study: Retrospective, consecutive series of patients

Patients and Methods: Sixteen consecutive patients (6 male/10 female; average age 33,5 years 19–60y) with persistent pain after surgical hip dislocation for the treatment of femoroacetabular impingement were included. At the index surgery, all patients had an osteo-chondroplasty of the head neck junction and a resection of the acetabular rim with reattachment of the labrum in 9 cases. All patients had a preoperative arthro-MRI and were treated with arthroscopy of the hip.

Results: At arthroscopy all reattached labra were stable. In the cases without preservation of the labrum, the joint capsule was attached level with the acetabular rim and had important synovitis. All patients had adhesions between the neck of the femur and joint capsule or between labrum and capsule. In 3 patients the arthroscopic procedure was technically limited by massive thickening of the capsule. Overall 75% (12 of 16) patients showed less pain or were pain free. MDA improved from preoperatively 13 to 16 points at last follow up.

Conclusions: Persistent pain after surgical dislocation of the hip could result from intraarticular adhesions that can be shown in the MRI. Hip arthroscopy after previous surgery can be demanding due to scarring. If the adhesions can be released good results can be achieved. Hip arthroscopy is a save therapeutical tool to treat patients with intraarticulary adhesions after surgical dislocation of the hip for femoroacetabular impingement.

Introduction: In the treatment of polytraumatised patients acetabular fractures are challenging because of the necessity of perfect open reduction of the articular surface over an anatomy respecting approach. Luxation of the femoral head with accompanying Pikin fracture, interponated fragments and labral lesions are relevant additional injuries compromising a good result after correct operative treatment. The choice of the approach is a limiting factor for the visualization of the hip joint and is of capital importance for adequate internal fixation. A modified Kocher-Langenbeck- approach with osteotomy of the grater trochanter allows an anatomic reduction under perfect visualization with protection of the soft tissue.

Patients and Methods: This prospective study was accomplished from 1995–2003 including 60 patients (16 female, 16–80years) with an actabulary fracture (posterior wall-, T-type-, and transverse fracture) treated over a modified Kocher-Langenbeck-appraoch with osteotomy of the grater tro-chanter. The included patients had a minimum follow-up of 2 years with clinical and radiological examination. The outcome was assessed with the Merle d’Aubigné-score and degenerative changes with the Tönnis classification.

Results: Within 57 patients an anatomic reduction was achieved. In 3 patients the reduction was not anatomical but satisfactory (1–3mm). Arthrotic changes in the minimujm follow-up of 2 years were observed in 14 patients (8 Ps grade I, 3 Ps grade II, 3 Ps grade III). In 3 patients posttraumatic arthritis had to be treated with THR (1, 3, 8 years postoperatively). A avascular necrosis was not objected.

Conclusion: The treatment of suitable acetabular fractures over a modified Kocher-Langenbeck-approach with a osteotomy of the greater trochanter and dislocation of the femoral head is a safe method for anatomic reduction and internal fixation

Introduction: Glenoid version seems to play an important role in the loading and stability of the glenohumeral joint. Measurement of Glenoid version on standard x-rays has been shown to be inaccurate. The purpose of this study was to assess the accuracy of the glenoid version measured on standard CT scans.

Material and Methods: The version of the glenoid was assessed using a multislice CT. We analysed 60 scapulae in 47 Patients (32 male; 18 to 83 years; 17 osteoarthritis and 29 instability). The retroversion of the glenoid was measured in 2 planes. First on the standard axial plane and second in a corrected axial plane (multiplanar reconstruction of scapula in a “true” axial plane with respect to the three-dimensional adjustment of the scapula).

Results: In the standard axial plane the mean retroversion was 8° (range, −5° to 22°). In the correct axial plane the difference of the retroversion was averages 6° compared to the standard axial plane. The range of the error was form 0° to 15°.

Conclusion: Measurement of glenoid retroversion on standard axial ct scans was unreliable. The clinical relevance: The standard shoulder CT is not suited for the preoperative planning of the glenoid correction. Therefore we would advocate the assessing of the glenoid version a defined “true” axial plane obtainable trough multiplanar reconstruction.