Stefan Budde

PSI kinematic versus non-PSI mechanical alignment in total knee arthroplasty: a prospective, randomized study

PurposeKinematic alignment in TKA is supposed to restore function by aligning the components to the premorbid flexion–extension axis instead of altering the joint line and natural kinematic axes of the knee. The purpose of this study was to compare mechanically aligned TKA to kinematic alignment.MethodsIn this study, 200 patients underwent TKA and were randomly assigned to 2 groups: 100 TKAs were performed using kinematic alignment with custom-made cutting guides in order to complete cruciate-retaining TKA; the other 100 patients underwent TKA that was manually performed using mechanical alignment. The WOMAC and combined Knee Society Score (KSS), as well as radiological alignment, were determined as outcome parameters at the 12-month endpoint.ResultsWOMAC and KSS significantly improved in both groups. There was a significant difference in both scores between groups in favour of kinematic alignment. Although the kinematic alignment group demonstrated significantly better overall results, more outliers with poor outcomes were also seen in this group. A correlation between post-operative alignment deviation from the initial plan and poor outcomes was also noted. The most important finding of this study is that applying kinematic alignment in TKA achieves comparable results to mechanical alignment in TKA. This study also shows that restoring the premorbid flexion–extension axis of the knee joint leads to better overall functional results.ConclusionKinematic alignment is a favourable technique for TKA.Clinical relevanceThe kinematic alignment idea might be a considerable alternative to mechanical alignment in the future.Level of evidenceII.

Clinical results of the metha short hip stem: a perspective for younger patients?

In recent years, various uncemented proximal metaphyseal hip stems were introduced for younger patients as a bone preserving strategy. Initial osteodensitometric analyses of the surrounding bone of short stems indicate an increase of bone mass with secondary bone ingrowth fixation as a predictor of long-term survival of these types of implants. We report the outcome of 151 modular Metha short hip stem implants in 148 patients between March 2005 and October 2007. The mean follow-up was 5.8±0.7 years and the mean age of the patients was 55.7±9.8 years. Along with demographic data and co-morbidities, the Harris Hip Score (HHS), the Hip dysfunction and Osteoarthritis Outcome Score (HOOS), and also the results of a patient-administered questionnaire were recorded pre-operatively and at follow-up. The mean HHS increased from 46±17 pre-operatively to 90±5 the HOOS improved from 55±16 pre-operatively to 89±10 at the final follow-up. A total of three patients have been revised, two for subsidence with femoral revision and one for infection without femoral revision (Kaplan Meier survival estimate 98%). The radiological findings showed no radiolucent lines in any of the patients. The modular Metha short hip stem was implanted in younger patients, who reported an overall high level of satisfaction. The clinical and radiographic results give support to the principle of using short stems with metaphyseal anchorage. However, long-term results are necessary to confirm the success of this concept in the years to come.

Access to the Hip Joint From Standard Arthroscopic Portals: A Cadaveric Study

PURPOSE Our purpose was to study and describe the areas of the hip joint that can be safely visualized and operated on using a variety of portals for the central and peripheral compartments. METHODS Twelve hip joints in 6 human cadavers were examined through 9 different central and peripheral arthroscopic portals. Markings of the accessible areas within the joint were made through an arthroscope. Dissection of the cadavers was carried out for final evaluation of the visible areas and those accessible for instruments. During dissection, anatomic proximity of the portals to relevant neurovascular structures was measured. RESULTS The central compartment was sufficiently accessible using the anterior, anterolateral, and posterolateral portals, with slight limitations in the posteromedial corner. A more medial portal did not offer substantial advantages regarding accessibility but decreased the safety distance to the femoral nerve. With regard to the peripheral compartment, the combination of the anterolateral and posterolateral portals allowed visualization of most of the joint. It was observed that the structure at highest risk of injury for the central anterior and the peripheral anterolateral portals was the lateral femoral cutaneous nerve. CONCLUSIONS In hip arthroscopy, the use of the standard anterior, anterolateral, and posterolateral portals allows proper accessibility of the central compartment, with slight limitations in the posteromedial corner. A more medial portal is not recommended with regard to its risk-benefit ratio. The peripheral compartment of the hip joint is sufficiently visible using the anterolateral and posterolateral portals. For treatment of specific pathologic conditions, a variation of these portals improves surgical accessibility. The anatomic structure at highest risk of injury during hip arthroscopy is the lateral femoral cutaneous nerve. CLINICAL RELEVANCE The general objectives of this study were to prepare surgeons to develop appropriate concepts of surgery and to facilitate preoperative planning.

Short-stem hip arthroplasty in osteonecrosis of the femoral head.

IntroductionOsteonecrosis of the femoral head (ONFH) is a locally destructive and complex disorder. Without treatment, infraction of the femoral head is likely. There is also a lack of consensus in the literature about the most appropriate arthroplasty method in patients with progressive ONFH. During the last decade, the number of short-stem prostheses has increased. Some short-stem designs have a metaphyseal anchorage. It is questionable whether ONFH represents a risk factor for failure after implantation of short stems. The aim of this study was to review existing literature regarding the outcome of short-stem arthroplasty in ONFH and to present the pros and cons of short-stem hip arthroplasty in osteonecrosis of the femoral head.Materials and methodsThis review summarises existing studies on short-stem hip arthroplasty in osteonecrosis of the femoral head.ResultsFew studies have analysed the clinical and radiological outcome of short-stem THA in patients with ONFH. Only a handful of studies present clinical and radiological outcome after implantation of a short-stem arthroplasty in patients with the underlying diagnosis of osteonecrosis of the femoral head.ConclusionThe short- to medium-term results show predominantly good outcomes. However, due to differences in the design of short stems and their fixation, it is hard to draw a general conclusion. Short stems with primary diaphyseal fixation do not reveal a high increased risk of failed osseointegration or loosening. For designs with a primary metaphyseal anchorage, an MRI should be conducted to exclude that the ostenecrosis exceeds the femoral neck.

Seeding a human tendon matrix with bone marrow aspirates compared to previously isolated hBMSCs --An in vitro study

Injuries of tendons and ligaments give rise to significant morbidity. Tissue engineering offers promising treatment concepts such as seeding a scaffold with human bone marrow stem cells (hBMSCs) to create high-quality tendon replacement tissue. HBMSCs are usually isolated and cultured prior to seeding. Studies evaluating if previous isolation is superior to seeding with bone marrow aspirates have not been published yet. The aim of this study was to compare these two seeding methods in terms of cell viability, proliferation and differentiation. HBMSCs were harvested from the iliac crest during routine trauma surgery. In group A the scaffold (human achilles tendons) was seeded with bone marrow aspirates, while in group B hBMSCs were isolated, harvested and then seeded. Constructs were stimulated in perfusion bioreactors according to established protocols. Mean cell proliferation was significantly increased (p< 0.05) on tendons seeded with bone marrow aspirates. Cell viability, the concentration of alkaline phosphatase in the perfused media and the synthesis of procollagen - III - polypeptide (PIIIP) were not significantly different when comparing the two groups. The synthesis of procollagen-I-polypeptide (PIP) was significantly increased on tendons seeded with previously isolated hBMSCs p < 0.05). The results indicate that seeding a human tendon matrix scaffold with bone marrow aspirates may be equal to seeding with previously isolated hBMSCs. This new seeding method could facilitate and speed up the tissue engineering process.

CCD and offset after Nanos short stem in total hip arthroplasty

BACKGROUND Many short stems for total hip arthroplasty have been introduced by the manufacturers only during the last decade. One of them is the Nanos short stem (Smith and Nephew, Marl, Germany). The development of short stems was aimed at preserving bone and soft tissue by utilizing a minimally invasive approach, thus allowing a quick return to an active life. It was purpose of this study to evaluate the radiological changes after using this device. METHODS We present the radiological results of 202 cementless THAs which were performed in 172 patients using the Nanos stem. Radiological evaluation was performed using standing anterior-posterior (AP) and lateral radiographs of the proximal femur preoperatively, postoperatively and during the follow up. We analyzed the preoperative and postoperativ CCD angle, the subsisdence, preoperative and postoperative offset, osteolysis, bone resorption, increased density, neocortex and periarthricular ossifications. RESULTS One stem had to be revised due to subsidence four days after implantation. Two cups (BiconPlus, Smith and Nephew, Marl, Germany) had to be revised during the time of follow up due to an aseptic cup loosening. Two stems showed radiolucent lines at the implant-bone-interface at the last follow-up. An increase of bone density could be detected in 18 hips (8.9%). 14 hips showed periarticular ossifications. Measurable subsidence was detected in a total of four stems (1.9%). The preoperative neck-shaft-angle angle was 133.8 ± 4.4° (range: 118.5-146.2) and the neck-shaft-angle angle at the time of follow up was 134.6 ± 4.3° (range: 123.3-147; P< 0.05). The preoperative and postoperative offset changed from 109.3 ± 11.9 mm (range: 80.9-131.6) to 109.7 ± 12.3 mm (range: 79.7-155.6; P< 0.05). CONCLUSION In summary, this study shows that a correct anatomical reconstruction is possible with a device of this design. The outcome is comparable to that of other short stems. Further studies should be performed in a prospective and randomized design to evaluate the advantage of such a device with a higher level of evidence.

Magnesium-containing layered double hydroxides as orthopaedic implant coating materials--An in vitro and in vivo study.

The total hip arthroplasty is one of the most common artificial joint replacement procedures. Several different surface coatings have been shown to improve implant fixation by facilitating bone ingrowth and consequently enhancing the longevity of uncemented orthopaedic hip prostheses. In the present study, two different layered double hydroxides (LDHs), Mg-Fe- and Mg-Al-LDH, were investigated as potential magnesium (Mg)-containing coating materials for orthopaedic applications in comparison to Mg hydroxide (Mg(OH)2). In vitro direct cell compatibility tests were carried out using the murine fibroblast cell line NIH 3T3 and the mouse osteosarcoma cell line MG 63. The host response of bone tissue was evaluated in in vivo experiments with nine rabbits. Two cylindrical pellets (3 × 3 mm) were implanted into each femoral condyle of the left hind leg. The samples were analyzed histologically and with μ-computed tomography (μ-CT) 6 weeks after surgery. An in vitro cytotoxicity test determined that more cells grew on the LDH pellets than on the Mg(OH)2-pellets. The pH value and the Mg(2+) content of the cell culture media were increased after incubation of the cells on the degradable samples. The in vivo tests demonstrated the formation of fibrous capsules around Mg(OH)2 and Mg-Fe-LDH. In contrast, the host response of the Mg-Al-LDH samples indicated that this Mg-containing biomaterial is a potential candidate for implant coating.

Bone Turnover Markers Failed to Predict the Occurrence of Osteonecrosis of the Femoral Head—A Preliminary Study

Background: The early detection of osteonecrosis of the femoral head (ONFH) is difficult, but important for prevention of destruction of the femoral head. The objective of this study was to determine whether the occurrence of osteonecrosis of the femoral head (ONFH) correlates with changes in bone turnover markers.

Feasibility of arthroscopic placement of autologous matrix-induced chondrogenesis grafts in the cadaver hip joint.

An assortment of clinical trials have been done presenting the effectiveness of autologous matrix-induced chondrogenesis (AMIC) for the regeneration of chondral leasions. The purpose of the study was to underline the accessability of the acetabulum and the femoral head through the known portals and prove i) the feasibility of placing the AMIC in the different zones of the hip joint and ii) check for dislocation after joint movement. Six human cadavers underwent hip arthroscopy on both hips. Two chondral lesions were set on each femoral head and two in the acetabulum to evaluate a total of 48 defects. After microfracturing an autologous matrix-induced chondrogenesis graft was placed on these lesions arthroscopically. After repeated joint movement the dislocation of the graft was checked. It was possible to place the AMIC graft in all 48 chondral lesions. The time needed for placing the graft was 8±2.9 minutes. A trend of time reduction could be detected throughout this study as the surgeon gained more experience. For the femoral head, after twenty cycles of joint movement 18/24 spots showed no displacement, 4/24 showed minor displacement (<3 mm) and 2/24 showed major displacement (>3 mm). None showed total displacement. For the acetabulum 22/24 spots showed no displacement and 2/24 showed minor displacement. A combined microfracturing and placing of an AMIC graft of focal chondral lesions of the hip joint can be done arthroscopically. Prospective randomized in vivo studies should compare the results of arthroscopilally placed AMIC grafts with microfracturing and microfracturing alone.

A short-stem hip implant with metaphyseal anchorage in patients with developmental dysplasia of the hip

BACKGROUND Short-stem implants are routinely used for total hip arthroplasty in younger patients that are more likely to have secondary osteoarthritis than older patients. OBJECTIVE To investigate the applicability of short-stem hip implants for secondary osteoarthritis due to developmental dysplasia of the hip. METHODS This study analyzed the clinical and radiological results of patients with developmental dysplasia of the hip (DDH, 58 hips) and compared them to those of patients with primary osteoarthritis (POA, 59 hips) treated with the metaphyseal total hip arthroplasty (Metha®) short stem with metaphyseal fixation. RESULTS The mean clinical and radiological follow-up periods were 2.9 ± 1.1 years and 3.8 ± 1.9 years, respectively. The mean Harris Hip Score (HHS) significantly increased in both groups over this period (p< 0.0001). The caput-collum-diaphysis (CCD) angle was significantly lower in the POA group prior to surgery and significantly increased in the POA and and decreased in DDH groups, respectively. The preoperative femoral offset was lower in the DDH group and increased significantly after surgery. CONCLUSIONS The Metha® short stem in patients with DDH allows good reconstruction of joint biomechanics with a good clinical outcome.