Introduction

The treatment osteonecrosis of the femoral head remains uncertain. Core decompression is the standard technique for the early stages (ARCO I and II). A new alternative is core decompression combined with the insertion of an osteonecrosis rod. This implant is supposed to reduce the intraosseous pressure and to give additional structural support. The aim of this study was to evaluate the clinical and radiological outcome via magnetic resonance imaging (MRI) of this new technique.

Introduction: High developmental hip dislocation is the most severe anatomic constitution type in developmental dysplasia of the hip (DDH). After the age of 30–40 years the pseudo-articulation often becomes painful and requires advanced treatments. To restore limb length dislocation must be reduced by soft tissue release. If the reduction overreaches 40 mm the risk for nerve-damage increases dramatically. Reducing the dislocation, one-step soft tissue releases and slow release by continuous iliofemoral distraction were invented. In this study we report a combination of a one-step soft tissue release and slow continuous iliofemoral distraction in patients requiring over 40 mm distraction for uncemented THA.

Material and Methods: Between 1998 and 2007 20 procedures in 19 patients with an age of 42.5 years (18–69 years) and a leg-length discrepancy of > 4 cm were performed. For 5.6 years (1–12 years) patients were followed-up clinically and radiographically. The treatment consisted of a two-step procedure. 1st operation: Soft tissue releases combined with the implantation of the THA components and placement of the external distraction apparatus. In the interval period slow iliofemoral distraction of 1mm–1.5 mm per day was conducted. Neurovascular signs and distraction was regularly monitored until the desired length was achieved. 2nd operation: the external fixation device was removed before applying the acetabular PE-inlay and the femoral head. Subsequent reduction was easy in most cases.

Results: A distraction of 51 mm (41 mm–75 mm) in 61 days (32–94 days) with an indicated speed of 1–1.5 mm/d and an effective speed of 0.8 mm (0.4 mm/d–1.8 mm/d) was achieved. Treatment time was 86 days (50–210 days). Patients had to maintain 132 days (40–300 days) restricted weight bearing. 2.6 (2–6) interventions were performed until final reduction. Harris Hip Score increased by 43 points [44 (22–65) to 83 points (66–98)]. The patients showed satisfying increases in all dimensions of the SF-36 health score. In the course of treatment pin-instability was seen in 6 cases, 3 minor intraoperative femoral fractures, 3 infections and 3 nerve damages occurred.

Discussion: The experiences of this study state the difficulties in the treatment of high DDH. The complication rate was high, but patients seemed to be satisfied finally. However, final scores were lower than in patients undergoing hip arthroplasties for degenerative osteoarthritis. Results of this treatment can be improved by avoiding certain pitfalls like insufficient soft tissue release, trans-cortical placement of the iliac screws or fast distraction. Nevertheless, soft tissue release and continuous iliofemoral distraction is the only option to restore limb-length and to preserve neurologic structures in cases with a dislocation over 40 mm.

Introduction: Besides other techniques to reduce blood loss, the use of pneumatic tourniquet is commonly accepted in total knee arthroplasty (TKA). Furthermore it is used to maintain a clean and dry operative field to improve visualization, to use a better cementing technique, and to reduce operating time. The time of tourniquet release is discussed controversially in literature. However, there are only a few prospective randomised studies that compared the effect of timing of tourniquet release in cementless or cemented TKA. To our knowledge, this is the first study that investigated the influence of tourniquet release on blood loss in a randomized prospective study in simultaneous bilateral cemented TKA.

Methods: 20 patients (40 knees) underwent simultaneous bilateral cemented TKA with the cemented Triathlon Knee System (Stryker) between February and May 2006. The mean age of the patients was 67 years (67+/−11 years). 7 males and 13 females were treated with TKA (mean tourniquet pressure: 282.5+/−33.5 mm Hg). In 20 patients one knee was operated with tourniquet release and hemostasis before wound closure (“Technique A”), and the other knee with tourniquet release after wound closure and pressure dressing (“Technique B”). To determine the order of tourniquet release technique in simultaneous bilateral TKA, the patients were randomized in two groups: “Group A” (20 knees) first knee with tourniquet release and hemostasis before wound closure, and “Group B” (20 knees) second knee with tourniquet release and hemostasis before wound closure. The patients were given low molecular weight heparin and a leg dressing to prevent deep vein thrombosis. The blood loss was monitored two days after surgery till removal of the wound drains.

Results: We found no significant difference in total blood loss between “Technique A” (753+/−390 ml) and “Technique B” (760+/−343 ml) (p=.930). Furthermore there was no significant difference in total blood loss between both techniques after randomizing in “Group A” (“Technique A” 653+/−398 ml; “Technique B” 686+/−267 ml; p=.751) and “Group B” (“Technique A” 854+/−374 ml; “Technique B” 834+/−406 ml; p=.861). However, the operating time showed a significant difference between “Technique A” (58+/−18 minutes) and “Technique B” (51+/−17 minutes) (p=.035).

Discussion: In this study we compared the effect of timing of tourniquet release on perioperative blood loss in a randomized prospective study in simultaneous bilateral cemented TKA. Our results showed no significant difference of blood loss but a significant difference of operation time. Therefore, we recommend a tourniquet release after wound closure to reduce operating time and to minimize the risk of peri- and postoperative complications at approximately similarly blood loss between both techniques.

Introduction: The goal of meniscal transplantation is to prevent progressive joint degeneration that predictably follows meniscectomy. The meniscal transplant’s ability to transfer load effectively depends on its ability to bear circumferential loading. Purpose of this study was thus to investigate the influence of intraoperative pre-tensioning on the chondroprotective of meniscal transplants in a sheep model.

Methods: Thirty-six sheep were divided into 6 groups (n = 6), subjected to a sham operation (group A), a meniscectomy (group B), or a meniscal autograft using tag sutures with different levels of pre-tensioning (group C, 0 N; group D, 20 N; group E, 40 N; group F, 60 N). Macroscopic (International Cartilage Repair Society score) and histological evaluation (Mankin score) of the articular cartilage was performed after 6 months.

Results: Higher suture pretension (40 N, 60 N) resulted in less cartilage degeneration than in meniscectomized (P =.047; P =.036) and non-pre-tensioned (P =.028; P =.015) knees, with International Cartilage Repair Society scores of 1.63 +/− 0.57 and 1.66 +/− 0.51 in groups E and F, respectively, and scores of 2.40 +/− 0.27 and 2.68 +/− 0.46 observed after meniscectomy and meniscal transplantation with no pre-tensioning, respectively. Group F had a significantly better Mankin score of 6.66 +/− 2.15 (P =.05) compared with group D. Regarding criterion cells, trends toward less degeneration compared with meniscectomized and non-pretensioned knees (P =.054 and P =.055) were found. The coefficient of variation of the Mankin scores was greater than that of the International Cartilage Repair Society score. Group A had significantly better cartilage than all other groups.

Conclusion: Adequate intraoperative pre-tensioning has an influence on the chondroprotective effect of meniscal transplants but did not prevent the development of articular cartilage degeneration.

Clinical Relevance: The results suggest that intraoperative pre-tensioning could improve the chondroprotective effect of meniscal transplantation.

Introduction: Revision in total hip arthroplasty (THA) continues to be a technical challenge because of difficulties in fixation of the femoral component in mostly deficient bone in the proximal femur. In the past, the use of primary stems in revision surgery has also been described by many authors. Very often, the cortical bone is not sufficient enough for torsional or axial load bearing. In this retrospective study we present our clinical results of femoral component revision surgery using the uncemented primary BiCONTACT stem (Aesculap).

Methods: In this study, seventy-nine patients were examined who underwent a revision of the femoral component in total hip arthroplasty (THA) with the uncemented primary BiCONTACT stem between December 1991 and April 2004 (mean follow-up 6.8+/−3.9 years). Only patient with a defect classification of Paprosky I–II were analysed. The average patient age was 67.1+/−10.1 years (range from 34–87 years). Forty-six female and thirty-three male patients (168+/−10 cm mean height, 75+/−12 kg mean weight, mean Body Mass Index: 26.4+/−2.5) were included in the study. All patients were clinically evaluated both preoperatively and postoperatively using the Harris Hip Score (HHS), a pain score (from 0 [no pain], to 10 [max. pain]) and a motion score (from 0 to [no flexion], to 10 [max. flexion]). Furthermore, the radiographs (anteroposterior and axial) before, after surgery and at follow-up were analysed concerning femoral defects, proximal bone loss, and to determine the quality of bony fixation. The defects were classified using the Paprosky classification. For statistical analysis, the paired Student t-test was used for preoperative and postoperative data.

Results: The postoperative Harris Hip Score (78.9+/−12.5, p < 0.001), Range of Motion Score (p < 0.05) and Pain Score (p =0.005) improved significantly. During follow-up there were only four re-revisions within two years after revision surgery: two re-infections in the first year, two aseptic loosening in the second year. There were only two cases of mild stress shielding. The survival curve (Kaplan-Meyer) showed a 10-years survival rate of 96.2 %. In two cases we found intraoperative periprosthetic fractures and in fourteen cases small fissures during removal or implantation of the stem.

Discussion: The primary uncemented BiCONTACT stem appears to be a good alternative to other revision systems in well-selected femoral revision cases with minor defects. The results of this study correspond to those published before, using a primary cementless stem in cases of revision. Therefore, in cases of minor proximal and metaphyseal bone defects (Paprosky I–II) the use of a primary stem in femoral revision should be considered. However, an exact preoperative planning, intraoperative assessment of bone stock, and experienced surgeon is necessary.

Objective: To determine the effect of intraoperative pre-tensioning of meniscal transplants on the tibial plateau in an animal experiment:

Material and Methods: Thirty-six sheep were used for this animal study. The animals were divided into 6 groups: -group A was the sham group; – in group B medial meniscectomy was performed; in group C-F medial meniscus transplantation with an autograft was carried out. In group C-F different defined pre-tensioning was applied to meniscal transplants via bone tunnel sutures (0N, 20N, 40N and 60N respectively). After 6 months the animals were sacrificed. The lower limb specimen were placed in a material testing machine under standard conditions in 30, 60 and 90 degrees of flexion and loaded through the femoral axis to 500N. For determining contact area a thin film pressure transducer (Tekscan) was positioned underneath the medial meniscus. Statistical analysis was performed using Mann-Whitney test.

Results: The mean contact pressure of the sham group and the groups with the transplanted meniscus was significantly lower in relation to meniscectomized knees. Significant increases in contact area and reductions in in peak contact pressure could be identified. At greater flexion angles only the meniscal transplantation group with the 40N pretension showed a significant increase of contact area and/or very strong trend in relation to meniscectomized knees. Concerning peak contact pressure, all meniscal transplantated groups with exception th 0N pre-tension group showed significant reduction in comparison to the meniscectomized group.

Conclusion: Regarding the results we can conclude that the biological ingrowth has an influence on the biomechanical effect of meniscal transplantation. For this animal model and with the compressive load of 500N especially 40N pre-tension of meniscal transplants seems to be efficient to provide load transmission function of the meniscus.