Comparison of anatomic axes with a navigated functional rotation axis determined by ligament tension for rotational femoral component alignment in cadaver knee arthroplasty.

INTRODUCION: The malimplantation of the total knee arthroplasty (TKA) components is one of the main reasons for revision surgery. For determining the correct intraoperative femoral rotation several anatomic rotational axes were described in order to achieve a parallel, balanced flexion gap. In this cadaveric study prevalent used rotational femoral axes and a navigated functional rotational axis were compared to the flexion-extension axis defined as the gold standard in rotation for femoral TKA component rotation. MATERIALS AND METHODS: Thirteen body donors with knee osteoarthritis (mean age: 78.85 ± 6.09; eight females and five males) were examined. Rotational computer tomography was performed on their lower extremities pre- and postoperatively. Knee joint arthroplasties were implanted and CT diagnostics were used to compare the preoperatively determined flexion-extension axis (FEA). The FEA is the axis determined by our surgical technique and serves as an internal reference. It was compared to other axes such as (i) the anatomical transepicondylar axis (aTEA), (ii) the surgical transepicondylar axis (sTEA), (iii) the posterior condylar axis (PCA) and (iv) the functional rotation axis (fRA). RESULTS: Examination of 26 knee joint arthroplasties revealed a significant angular deviation (p*** < 0.0001) for all axes when the individual axes and FEA were compared. aTEA show mean angular deviation of 5.2° (± 4.5), sTEA was 2.7° (± 2.2), PCA 2.9° (± 2.3) and the deviation of fRA was 4.3° (± 2.7). A tendency towards external rotation was observed for the relative and maximum axis deviations of the aTEA to the FEA, for the sTEA and the fRA. However, the rotation of the posterior condylar axis was towards inwards. CONCLUSIONS: All axes showed a significant angular deviation from the FEA. We conclude that the presented technique achieves comparable results in terms of FEA reconstruction when compared with the use of the known surrogate axes, with certain deviations in terms of outliers in the internal or external rotation.

Clinical outcome after dorso-ventral stabilization of the thoracolumbar and lumbar spine with vertebral body replacement and dorsal stabilization.

PURPOSE: Surgical stabilization of the spine by vertebral body replacement (VBR) is used for spinal disorders such as traumatic fractures to provide an anatomical re-adjustment of the spine to prevent late detrimental effects and pain [1-4]. This study addresses the clinical outcome after a ventral intervention with VBR and bisegmental fusion. METHODS: The study includes 76 patients (mean age: 59.34 ± 15.97; 34 females and 42 males) with fractures in the lower thoracic and lumbar spine. They were selected from patients of our hospital who received an anterolateral VBR surgery on the corresponding lower spine region over a nine-year period. Only patients were examined with X-rays and complete follow-up records. Exclusion criteria were changes due to degeneration and pathological fractures. Patients were divided into two groups, the thoracotomy group (Th10-L1) and the lumbotomy group (L2-5), respectively. Minimum one year after surgery, patients were asked about their well-being using a precasted questionnaire. RESULTS: No significant differences with respect to the subjective impression of the patients concerning their back pain, spinal functional impairment, their general functional status and their quality of life impairment. Unfortunately, however, only a rather modest but significant increase of the post-surgical life quality was reported. CONCLUSIONS: Patients who underwent VBR in the lower thoracic or lumbar spine show modest long-term well-being. The results suggest that injuries to the lower thoracic or lumbar spine requiring vertebral body replacement should be classified as severe injuries since they adversely affect the patients' long-term well-being. TRIAL REGISTRATION: Study of clinical outcome of patients after vertebral body replacement of the ventral thoracal and lumbal spine, DRKS00031452. Registered 10th March 2023 - Prospectively registered. Trial registration number DRKS00031452.

Changes of the subchondral bone microchannel network in early osteoarthritis.

OBJECTIVE: We have identified a 3D network of subchondral microchannels that connects the deep zone of cartilage to the bone marrow (i.e., cartilage-bone marrow microchannel connectors; CMMC). However, the pathological significance of CMMC is largely unknown. Here, we quantitatively evaluated how the CMMC microarchitecture is related to cartilage condition, as well as regional differences in early idiopathic osteoarthritis (OA). METHODS: Two groups of cadaveric female human femoral heads (intact cartilage vs early cartilage lesions) were identified, and a biopsy-based high-resolution micro-CT imaging was employed. Subchondral bone (SB) thickness, CMMC number, maximum and minimum CMMC size, and the CMMC morphology were quantified and compared between the two groups. The effect of joint's region and cartilage condition was examined on each dependent variable. RESULTS: The CMMC number and morphology were affected by region of the joint, but not by cartilage condition. On the other hand, the minimum and maximum CMMC size was changed by both the location on the joint, as well as the cartilage condition. The smallest CMMC were consistently detected at the load-bearing region (LBR) of the joint. Compared to non-pathological subjects, the size of the microchannels was enlarged in early OA, most noticeably at the non-load-bearing region (NLBR) and the peripheral rim (PR) of the femoral head. Furthermore, subchondral bone thinning was observed in early OA as a localized occurrence linked with areas of partial chondral defect. CONCLUSION: Our data point to an enlargement of the SB microchannel network, and a collective structural deterioration of SB in early idiopathic OA.

Do patients need advice and information to prevent infections - results of a single centre structured survey.

Background: Healthcare-associated infections are a major burden for hospitals, leading to morbidity and mortality and unnecessary medical costs. They can probably be reduced through what is known as patient empowerment. This study aims to address the question of whether patients are interested in receiving infection prevention and control information. Methods: Patients were asked in structured interviews whether they would like more information on infection prevention and control. Inclusion criteria comprised 2 groups of patients. Group 1 were patients undergoing elective total endoprosthesis (TEP) and Group 2 were patients tested positive for meticillin-resistant Staphylococcus aureus (MRSA). Results: The response rate was 38.4 % (163/425 patients). Approximately 75 % of the patients were interested in information on infection prevention and control. The topics of interest differed between the two patient groups: MRSA patients had a higher need for infection prevention and control information. TEP patients showed a high acceptance of antiseptic body wash and a willingness to pay for it themselves. Information given to patients should be group-specific and timely. Conclusion: Our data suggest a lack of information on infection prevention and control among patients and underline the importance of patient empowerment. The willingness of patients to pay personally for antiseptic wash should be assessed further.

Cartilage calcification is associated with histological degeneration of the knee joint: a highly prevalent, age-independent systemic process.

OBJECTIVES: To investigate if cartilage calcification (CC) is a systemic process, the purpose of this study was to determine the prevalence and the amount of meniscal/hyaline CC of the knee joint in the general population by high-resolution imaging (DCR) and to evaluate the association between CC with cartilage degeneration and age. METHODS: Cross-sectional DCR-study of 180 knee joints of 90 donors (42 female/48 male, mean age 62.3y). Histological hyaline (OARSI) and meniscal (Krenn) cartilage degeneration was determined of all knees. RESULTS: CC was observed in 100% of the donors (bilaterally in 98%), hyaline cartilage calcification (HCC) in 92% and meniscal calcification (MC) in 100%. CC was detected in more than three out of six distinct cartilage areas in 84.4% of all knees. The mean amount of CC correlated between both sides of donors, the different analyzed areas of the knee joint and between the various types of cartilage structures. There was more calcification in meniscal than in hyaline cartilage (factor 5.3) and in the medial than the lateral compartment (factor 1.2). HCC/MC were already detectable with only mild cartilage lesions and the amount correlated with histological cartilage degeneration, but not with age. CONCLUSIONS: The present study provides evidence that meniscal and hyaline CC occurs in a pattern that is compatible with CC being a systemically driven process and that meniscal fibrocartilage is more prone to calcification than hyaline cartilage. Furthermore, the age-independent association between the amount of CC and the grade of degeneration in both hyaline and meniscal cartilage, suggests that CC is an obligatory early event in initiating cartilage degeneration.

[Periprosthetic fractures around the knee]. / Periprothetische Frakturen rund um das Knie.

BACKGROUND: Periprosthetic fractures of the knee joint are complex injuries and frequently represent a challenge for the surgeon. OBJECTIVE: The aim of this review is to present and discuss the current classification and treatment options for periprosthetic knee fractures. MATERIAL AND METHODS: A selective review of the existing literature on periprosthetic fractures around the knee was performed in PubMed. The various classifications and treatment regimens are discussed with respect to the advantages and disadvantages and from this knowledge a new algorithm was developed. RESULTS: The classifications of periprosthetic fractures have changed in recent years and have been replaced by a uniform fracture classification; however, not only the radiological evaluation of the fractures is crucial to determine the treatment regimen for periprosthetic fractures. A thorough evaluation of the inserted endoprosthesis should be carried out in order to be able to decide between the treatment options of osteosynthesis and revision arthroplasty. Treatment options are available for osteosynthesis and revision arthroplasty that enable a safe treatment of these complex injuries. CONCLUSION: Periprosthetic fractures of the knee joint are complex injuries, requiring a thorough preoperative planning and an interdisciplinary treatment with trauma and endoprosthetic expertise.

[Revision surgery in acute periprosthetic knee joint infections]. / Revisionseingriffe bei akuten periprothetischen Kniegelenkendoprothesen-Infektionen.

OBJECTIVE: Reduction of pathogens in the knee joint by removal of infected periprosthetic soft tissue, irrigation and modular implant exchange of the total knee arthroplasty (TKA) to eliminate the infection and long-term preservation of the TKA. INDICATIONS: Early infection of TKA (<4 weeks postoperatively); acute hematogenous TKA infection (symptom duration <3 weeks). CONTRAINDICATIONS: Delayed (>4 weeks postoperatively) or chronic TKA infection; TKA loosening; difficult-to-treat pathogens; critical soft tissue with draining sinus tract. SURGICAL TECHNIQUE: Excision of the wound or old surgical scar (= primary approach to the knee joint). Preparation of subcutaneous tissue. Opening the joint capsule. Removal of the old suture in tissue layers. Five tissue samples taken for microbiological and 1 tissue sample for histopathological examination using an unused instrument from the knee joint. Debridement of the upper recesses with complete synovectomy. Partial resection of Hoffa's fat body. Eversion of the patella. Resection of peripatellar soft tissue and infection membranes from the medial and lateral part of the capsule. Removal of the polyethylene inlay. Débridement of the posterior joint capsule with protection of vessels and nerve. Systematic removal of avital and infected periprosthetic tissue. Checking for correct fit of the femoral and tibial part of TKA. Antiseptic rinsing of the joint cavity with mechanical cleaning of the TKA. Extensive irrigation of the joint cavity by jet lavage (3-5 l saline solution). Glove change of the surgical team and new operation coverage. Inserting new polyethylene. Layerwise wound closure. POSTOPERATIVE MANAGEMENT: Removal of redon drain on postoperative day 2. Physiotherapy and CPM. Removal of cutaneous suture about 2 weeks postoperatively. Antibiotic treatment for 12 weeks postoperatively (2 weeks intravenous, 10 weeks per oral). Checking of inflammatory markers. RESULTS: Using correct indications and therapy, up to 90% of patients with acute periprosthetic TKA infection can be successfully treated with infection elimination and TKA preservation.

Clinical, radiographic and biochemical characteristics of adult hypophosphatasia.

In this study, we report on clinical, radiographic and biochemical characteristics of 38 patients with adult hypophosphatasia. High-resolution peripheral quantitative computed tomography showed alterations of bone microstructure in a subgroup of 14 patients. Pyridoxal-5-phosphate levels correlated with the occurrence of fractures and the number of symptoms. INTRODUCTION: Hypophosphatasia (HPP) is a rare disorder with a wide range of clinical manifestations. A reduced enzymatic activity of alkaline phosphatase (ALP) is the key marker of the disease, causing an accumulation of ALP substrates such as pyridoxal-5-phosphate (PLP). The purpose of this retrospective study was to further characterize adult onset HPP. METHODS: We assessed clinical, radiographic and laboratory characteristics of 38 adult patients with HPP. Diagnosis of HPP was established by the combination of low-serum ALP, raised PLP levels and typical symptoms and was genetically confirmed in 32 patients. Dual-energy X-ray absorptiometry (DXA) and laboratory data were available in most patients. High-resolution peripheral quantitative computed tomography (HR-pQCT) was performed in 14 patients. RESULTS: Clinical characteristics included a wide spectrum of symptoms. A history of fracture was present in 15 patients (39%). Twenty-one patients (55%) complained about recurring headaches, 23 patients (61%) had recurring muscle pain, 4 patients (11%) suffered from severe muscle weakness and 18 patients (47%) showed dental abnormalities. Z-scores assessed by DXA were only slightly reduced in most adult HPP patients. HR-pQCT of 14 patients showed microstructural changes of trabecular and cortical bone compared to reference values of healthy subjects. The occurrence of fractures and multiple symptoms (>2 typical HPP symptoms) were associated with significantly elevated levels of PLP. CONCLUSION: Adult HPP presents with a wide range of clinical symptoms and is not associated with low bone mass in general. PLP seems to be a good marker for disease severity in adult patients as its level is correlated with the occurrence of fractures and number of symptoms.

Articular cartilage calcification of the hip and knee is highly prevalent, independent of age but associated with histological osteoarthritis: evidence for a systemic disorder.

OBJECTIVES: Based on the concept of a systemic predisposition for articular cartilage calcification (CC), the aim of this study was to determine the prevalence and amount of bilateral CC of hip and knee joints in an unselected sample cohort by high-resolution digital contact radiography (DCR) and to analyze the association of CC with histological OA. METHODS: Both hip and knee joints of 87 donors (48 m and 39 f; mean age 62) were analyzed by DCR in this post-mortem study of an unselected cohort of donors. Histological OA (OARSI) of the main load bearing area of femoral heads and medial femoral condyles was determined. RESULTS: The prevalence of CC of the femoral head was 96.6%, of the knee 94.3%. Bilateral calcification was detected in 79.3% of hips and 86.2% of knees. Concomitant CC of all four joints was detected in 69.0% of donors. There was no difference between the amount of CC of hips and knees (P = 0.47). The amount of CC of any given hip or knee correlated with that of the contralateral hip (rs = 0.54, P < 0.001) or knee (rs = 0.50, P < 0.001). There was a correlation between the amount of CC and histological OA (hips rs = 0.48, P < 0.001, knees rs = 0.30, P = 0.004), but not between CC and age (hips rs = -0.09, P = 0.42; knees rs = 0.10, P = 0.34). CONCLUSIONS: These data support the concept that articular CC occurs as the result of a systemic disorder. CC appears to be an early element of hip and knee OA pathogenesis independent of age.

Axial rotation in the lumbar spine following axial force wrench.

The report presents measurements of axial rotation of lumbar motion segments (L1/L2, L3/L4, L4/L5), particularly with small angles of rotation (in the range of +/-1 degrees) following axial force wrenches. The investigation focussed on determining the influence of geometrically varying configurations in axial wrench (consisting of axial torque and axial force) applied on the kinematics (as defined by the migrating instantaneous helical axis, IHA) of lumbar motion segments under constant resulting axial force, and relating IHA-migration to anatomical structures. In all segments, IHA migrated over several centimetres (up to 6 cm). The main portion of IHA-migration was linked to the angle of rotation interval of +/-1 degrees. 3. The shape of the IHA-migration was greatly dependent upon the position of the force line F(z). The-force-wrench-dependent wide IHA-migration found for the rotational angle interval of +/-1 degrees suggests that joint guidance predominates in segment kinematics. The segment kinematics can be adjusted by means of the geometrical configuration of the force wrenches. The design of non-fusion spine implants and FE calculations have to take into consideration joint guidance and muscular force distributions with small intervals of axial rotation.