Influence of variable hinge positioning on coronal and sagittal alignment in uniplanar medial open-wedge high tibial osteotomy.

Purpose: There is a high risk of increasing the posterior tibial slope (PTS) during medially opening-wedge high tibial osteotomy (mowHTO). Most recently, the idea of intentional simultaneous coronal and sagittal correction, using uniplanar cutting techniques has emerged. This study aims to examine the influences of variable hinge positioning and osteotomy gap height on the sagittal and coronal plane. Methods: Twenty uniplanar mowHTOs were performed in standardised (left) solid-foam proximal tibia models. In the different models, hinge position was rotated stepwise by 10°, between 90° (cutting straight medial to lateral) and 0° (cutting straight anterior to posterior) (n = 10). Additionally, gap heights of 5 and 10 mm were produced and analysed. Logistic regression analysis was performed to calculate a predictive regression formula for the relation between gap height, hinge rotation and the changes of medial proximal tibia angle (MPTA), medial and lateral PTS. Results: Between cutting angles of 90 and 20°, the MPTA was mainly influenced by the gap height (0.95° MPTA per 1 mm gap height), but not by the cutting angle. Between 20 and 0°, the MPTA was decreased by 3.6° per 10° of rotation, but not by the gap height. Between cutting angles of 90 and 10°, the PTS was increased linearly by 0.97° per 10° of rotation and by 0.61° per 1 mm gap height. Conclusion: In mowHTO with lateral hinge positions, the MPTA is mainly influenced by gap height. Changes of PTS can be avoided by a straight lateral hinge position. In posterior hinge locations (0-20°), changes of MPTA are mainly caused by hinge rotation, but not by gap height. Level of Evidence: Level III, Case-control study.

Outcomes of rotating versus pure hinge knee arthroplasty in the setting of one-stage exchange for periprosthetic joint infection.

PURPOSE: Rotating or pure hinge knee prostheses are often used in case of periprosthetic joint infection (PJI). Five-year survival data of rotating hinge implants ranging from 52 to 90%, whereas pure hinge data are sparse. This study describes the results of both hinge knee prostheses after one-stage septic exchange. METHODS: One hundred sixty-seven one-stage septic exchanges of a primary unconstrained total knee arthroplasty (TKA) to a cemented hinge prosthesis (117 rotating and 50 pure hinge TKAs) performed between 2008 and 2017 were retrospectively reviewed. Exclusion criteria were stem extensions or augments used in primary TKA, history of extensor mechanism reconstruction, and a follow-up less than two years after surgery. Rates of reinfection, mechanical failures, and all-cause revision-free survival data were documented. RESULTS: At five years, the all-cause revision-free survival was 77% (95% CI 69 to 82). Thirty-one patients (19%) had further revision for aseptic reasons. In the rotating hinge group, the mechanical failure rate was more than twice as high as in the pure hinge group (13% vs 6%), significantly influenced by higher body weight. At a mean follow-up of 6.7 years, 21 (13%) patients had a reinfection and underwent a further surgery. Reinfection rates did not differ between the two groups. CONCLUSION: The use of hinge TKA in the revision of PJI shows favourable five year infection-free and all-cause revision-free survival rates of 91% and 77%, respectively. Our study showed poorer results of the rotating hinge design. These results may help surgeons to choose proper implants in case of septic knee revision.

[Infectious, pathologic humeral fracture in a patient with sickle cell disease-A rare case?] / Infizierte, pathologische Humerusfraktur bei Sichelzellanämie ­ noch ein Einzelfall?

The vaso-occlusive crises of sickle cell disease are accompanied by bone necrosis, which favors endogenous bacterial colonization and thus osteomyelitis. This poses a major challenge for eradication and fracture management.A 22-year-old patient with sickle cell disease sustained a multifragmentary, humeral shaft fracture. During surgical management, pus drained from the fracture site and further diagnostic work-up revealed osteomyelitis with evidence of Klebsiella aerogenes. Septicemia due to Klebsiella aerogenes had been treated 5 months prior to the accident, which occured because of a vaso-occlusive crisis. This is associated with clustered bone necrosis and endogenous germ colonization. Eradication of the germs and fracture care become a challenge. Repeated surgical procedures with segmental transfer can be a successful treatment option.

Neutrophil-Lymphocyte Ratio and Lymphocyte-Monocyte Ratio correlate with Chronic Prosthetic Joint Infection but are not useful markers for diagnosis.

PURPOSE: To investigate reported correlations between Neutrophil-to-Lymphocyte (NLR) and Lymphocyte-to-Monocyte (LMR) ratios and their value in diagnosis of chronic prosthetic joint infection (PJI) in a large cohort of patients from a single specialist hospital. METHODS: Diagnostic aspirations of 362 patients under investigation for PJI were identified. Of the included patients 185 patients received a final diagnosis of PJI and 177 were classed as aseptic. Established criteria (ICM 2018) were employed to define PJI. Included in the analysis are differential white cell counts, C-Reactive Protein (CRP), Synovial Leukocyte Count, Synovial Alpha-defensin ELISA and Synovial Leukocyte esterase activity. Receiver-operator characteristic (ROC) curves were calculated for each of the available diagnostic tests together with the corresponding area under the curve values (AUC). Youden's index was utilized to identify the optimal diagnostic threshold point for the NLR and LMR. Other diagnostic tests were evaluated as per the threshold values previously defined in the literature and specified in the ICM criteria. RESULTS: Using Youden's Index to identify the optimal NLR cut-off within our cohort we established a value of 2.93. This yielded a sensitivity of 0.60 and specificity of 0.64. The area under the curve (AUC) of a receiving operator characteristics (ROC) curve was 0.625. Regarding the LMR the results demonstrate similar findings; a positive correlation with a diagnosis of infection but poor sensitivity and specificity. The AUC for LMR was 0.633 and was not superior to NLR (P = 0.753). CONCLUSIONS: There is a significant correlation between higher Neutrophil-Lymphocyte and Lymphocyte-Monocyte ratios, and a diagnosis of PJI. The sensitivity and specificity of this calculation is poor and the does not add value to the diagnostic algorithm for PJI. LEVEL OF EVIDENCE: Level III Retrospective Cohort analysis.

Long-term outcomes of total hip arthroplasty in patients with developmental dysplasia of the hip: a minimum 21-year follow-up.

PURPOSE: Early osteoarthritis (OA) due to developmental dysplasia of the hip (DDH) is a known indication for total hip arthroplasty (THA). Though screening tools and joint-preserving procedures have been established successfully, there still is a relevant number of patients suffering DDH. Due to the lack of long-term outcome studies, we like to close this gap and present the results of a highly specialized center. METHODS: The study included 126 patients, who were treated in our institution with primary THA for DDH between January 1997 and December 2000. At the time of final follow-up, at a mean of 23 years postoperatively, 110 patients (121 hips) were clinically evaluated using the Harris-Hip Score. In addition, complication and surgical revision rates were assessed. We collected surgery-related data like implant choice and special surgical features such as autologous acetabular reconstruction or femoral osteotomies. Additionally, the severity of preoperative DDH was measured radiographically according to Crowe classification. RESULTS: There were 91 female (83%) and 19 male (17%) patients with an average age of 51 ± 9.5 years (range 21-65) included. Mean follow-up was 23 ± 1.3 years (21-25), with a minimum of 21 years being necessary for inclusion. Using revision for any indication as primary endpoint, the Kaplan-Meier survivorship was 98.3% at 10 years and 81.8% at final follow-up. The overall revision rate was 18% (22 cases), which were split up as follows: 20 (17%) implant failures (loosened or broken components), one (1%) periprosthetic infection and one (1%) periprosthetic fracture. Regarding complications, we observed nine (7%) dislocations and one case (1%) with severe heterotopic ossification that required surgical excision. The mean Harris-Hip score at latest follow-up was 78 ± 14 points (32-95). CONCLUSIONS: Though implants and surgical techniques have improved over time, our results suggest THA in patients suffering DDH to be seriously challenging with relatively high overall complications in long-term observation and fair clinical outcome after 21 years postoperatively. There is evidence that prior osteotomy might be associated with a higher revision rate.

[Anterior plate osteosynthesis for multifragmentary patella fracture with additive stabilization of the distal pole using suture cerclage]. / Anteriore Plattenosteosynthese bei mehrfragmentärer Patellafraktur mit additiver Sicherung des distalen Pols mittels Faden-Cerclage.

OPERATION GOAL: The aims of the surgical treatment are the anatomical reduction of the articular surface and stabilization of a multifragmentary patella fracture with a distal pole fragment using plate osteosynthesis and additive suture tape cerclage to secure the distal fragment. INDICATION: Demonstration of the surgical procedure for a multifragmentary patella fracture in the knee joint of a male cadaver. SURGICAL TECHNIQUE: Start with a median prepatellar skin incision and splitting of the bursa and surrounding fascia. Lateral arthrotomy with proximal and distal extension for complete eversion and articular exposure of the multifragmentary fracture. The fracture is then reduced from the articular side using temporary K­wire fixation and reduction clamps, followed by screw osteosynthesis of the large fragments (e.g., distal and proximal poles). After selection of the plate it is fixed with locking screws. In addition, a suture cerclage according to Krakow and/or McLaughlin is applied distally and transosseously through the tibial tuberosity and proximally through the quadriceps tendon. The knotting of the McLaughlin suture cerclage should be done in 90° flexion of the knee joint. POSTOPERATIVE TREATMENT: Functional postoperative treatment with hard shell orthesis with movement limitation (30°, 60° and 90° for 2 weeks each) and partial weight bearing of 15-20 kg for 6 weeks is recommended. Full weight-bearing is only allowed in full extension. EVIDENCE: Plate osteosynthesis is biomechanically superior in comparison to the widely used tension band osteosynthesis. In multifragmentary fractures, additional augmentation with a suture tape cerclage seems to be appropriate. Due to the lack of study results there is currently no clinical evidence for this.

Anatomical risk factors for aseptic loosening of full hinge knee prosthesis in primary and revision TKAs.

INTRODUCTION: Risk factors (RF) associated with aseptic loosening (AL) in total knee arthroplasty (TKA) are poorly understood. Therefore, the aim of this study was to investigate the anatomical shape variations in relation to the inner-diameter of the femur and the tibia as prognostic RF for AL of full hinge prosthesis (FHP) in primary and revision TKA. MATERIALS AND METHODS: We retrospectively examined all patients, who underwent revision surgery (2003-2018) due to AL of the FHP in primary (n = 38) and revision TKA (n = 46). Diagnosis-appropriate controls without AL at minimum follow-up of 24 months were randomly collected for each group. Besides other risk factors, we also measured the inner diameter of the femur according to the Citak classification and of the tibia on anteroposterior radiographies. RESULTS: RF for AL are younger age in primary and revision as well as > 1 previous surgeries in revision TKA. The femoral index was shown to be a RF for AL in revision TKA (p = 0.001), but not in primary TKA. The novel tibial index was associated with AL in primary with AUC 0.776 (95% CI 0.67, 0.88), 65.8% sensitivity, 86.6% specificity and in revision TKA with AUC 0.817 (95% CI 0.73, 0.91), 82.6% sensitivity and 71.7% specificity. CONCLUSION: This is the first study to calculate the tibial measurements and the tibial index according to Citak et al. and to identify them as prognostic RF for AL of the full hinge knee prosthesis in TKA and confirm the femoral index as a RF for AL also in revision full hinge knee prosthesis. Therefore, the preoperative radiological evaluation should include the analysis of the anatomical shape variants in order to select the appropriate prosthesis design with a possibly enhanced prognosis.

Tranexamic acid is safe and effective in patients with heterozygous factor V Leiden mutation during total joint arthroplasty.

INTRODUCTION: Patients with an inherent hypercoagulable state are at a higher risk of venous thromboembolism (VTE) following total joint arthroplasty (TJA). Further administration of tranexamic acid (TXA) during TJA may increase the risk of VTE in these high-risk patients. There is no study that specifically analyzes the safety and efficacy of TXA during TJA in patients with factor V Leiden (FVL) mutation; therefore, the purpose of this study was to evaluate the safety and efficacy of TXA use on the risk of VTE and bleeding in patients carrying FVL mutation. MATERIALS AND METHODS: A total of 42 patients with FVL mutation (22 hips, 20 knees) and 40 control patients (20 hips, 20 knees) who underwent TJA were retrospectively reviewed. All patients received 1 g TXA intravenously 15 min before the skin incision and 2 g of TXA was administered locally at the surgical site as a periarticular injection. Pharmacological thromboprophylaxis (low-molecular-weight heparin) was administered to all patients. Estimated blood loss and in-hospital thromboembolic complications were compared between the groups. RESULTS: In both total knee arthroplasty (TKA) and total hip arthroplasty (THA) patients, there was no significant difference in the amount of estimated blood loss among the groups (p = 0.980, and p = 0963, respectively). None of the patients in the THA group received a blood transfusion. The transfusion rate was similar in the TKA group (p = 0.756, one patient in each group). No VTE, myocardial infarction, or any other complications related to TXA use were observed in any of the patients. CONCLUSIONS: The combined local and systemic administration of TXA could be safely used in patients with heterozygous FVL mutation receiving pharmacological thromboprophylaxis during TJA without increasing the risk of VTE.

Midterm clinical outcome of uncemented short-stem reversed shoulder arthroplasty.

INTRODUCTION: While the incidence of reverse total shoulder arthroplasty (rTSA) is increasing constantly, newer implants with designs other than the classic Grammont geometry are gaining importance. More anatomic inclination angles and lateralization are supposed to have a positive impact on clinical results and complication rates. Presentation of midterm results therefore is important to support these assumptions. The aim of this study was to report the midterm clinical outcome of primary rTSA with an uncemented humeral short-stem prosthesis (USSP) with a humeral inclination angle of 145° and the analysis of different variables on the outcome. METHODS: This is a retrospective study of all patients with primary rTSA using an USSP and a combined humeral inclination angle of 145° (Ascend™ flex, Stryker) with a minimum clinical follow-up of 2 years. The implant combines a 132.5° inclination for the humeral stem with an additional 12.5° for the polyethylene inlay. Primary outcomes were patient-reported outcome measures: ASES score, simple shoulder test (SST) and subjective shoulder value (SSV). Secondary outcomes were complication and revision rates. We analyzed different variables: preoperatively gender, age, indication for surgery and status of rotator cuff. Also, the glenoid morphology was classified according to Walch and a proximal humerus cortical bone thickness measurement (CBT avg) of 6 mm was used as a threshold for osteoporosis. Postoperatively, we analyzed different radiologic parameters: filling ratio, distalization and lateralization angles according to Boutsiadis. RESULTS: A total of 84 out of 99 (85%) patients with a mean FU of 46.7 months (range 24-80 months) could be included: 62 women and 22 men with a mean age of 74.7 years. Mean ASES score significantly increased from 47 preoperatively to 85.8 at the last follow-up (p = 0.001). The postoperative SST reached an average of 65.3 and the mean SSV was 83%. None of the variable parameters analyzed could be identified as a risk factor for a lower outcome defined as a SSV < 70. Three patients (3.6%) had a complication: one incomplete lower plexus lesion, one dislocation and one major hematoma. Surgical revision was needed in two cases (2.4%). CONCLUSION: The midterm clinical outcome of primary reverse total shoulder arthroplasty (rTSA) with an uncemented humeral short stem and a humeral inclination angle of 145° showed good-to-excellent results with a low complication and revision rate independent from a wide range of pre- and postoperative variables. PROMs are comparable to those reported for anatomic TSA with a low complication rate, different to historical studies especially with the Grammont design. LEVEL OF EVIDENCE: Treatment study, Level IV.

The anatomical shape of the distal femur is an independent risk factor for aseptic loosening following one-stage septic knee revision using rotating hinge knee prosthesis.

PURPOSE: Aseptic loosening (AL) is the second most common reason for failure after one-stage septic knee revision. In this context, the goal of the study is to identify risk factors for AL following one-stage septic knee revision using rotating hinge implants. We aimed to answer the following research question: How does the anatomical shape of the distal femur represent an independent risk factor for AL following one-stage septic knee revision arthroplasty? METHODS: Patients, who had undergone re-revision surgery due to AL of the rotating hinge knee prosthesis after one-stage septic knee revision arthroplasty between January 2008 and December 2018, were included. For this purpose, 41 patients with AL after one-stage septic knee revision using rotating hinge implants and 37 controls without any revision surgery at latest follow-up were included in this study. Using standardized anteroposterior (AP) views of the knee in all patients, we measured the inner diameter of the femur 20 cm proximally from the joint line and at a point 2 cm proximally from the adductor tubercle. RESULTS: Among the vast majority of AL cases, we identified an isolated loosening of the femoral component. The AL group showd a high distribution of the Type C according to the Citak classification with 75.7%. Contrary to this, with 24.3% (p < 0.001) the amount of Type C cases was relatively low in the control group. Consequently, Type C configurations of the distal femur represent an independent risk factor for AL with an approximately sevenfold higher risk for AL compareed to Type A and Type B. CONCLUSIONS: The novel radiological classification system of the distal femur shows that the Type C subtype is an independent and main risk factor for AL after one-stage septic knee revision using rotating hinge knee implants.

[Arthrofibrosis of the hip joint : Diagnostic and therapeutic challenge]. / Arthrofibrose des Hüftgelenks : Diagnostische und therapeutische Herausforderung.

Arthrofibrosis is a frequent complication after total knee arthroplasty (TKA). Recently, arthrofibrosis could be successfully verified histologically after primary total hip arthroplasty (THA) and the clinical presentation on the hip could be described for the first time. Possible diagnostic and therapeutic approaches have not yet been published. The diagnostic work-up differs only slightly from that for the knee joint. Other causes, such as aseptic loosening, malalignment or periprosthetic joint infection should be excluded. The gold standard is still invasive diagnostics with histological evidence of arthrofibrosis according to the synovia-like interface membrane (SLIM) criteria. Conservative treatment approaches include mobilization under anesthesia and medication according to Traut, analogous to the knee joint. Surgical treatment should be carried out under strict interpretation of the indications and after detailed clarification for the patient. In contrast to the knee joint, open arthrolysis should be preferred to arthroscopic arthrolysis of the hip joint. It must be taken into consideration that the evidence for conservative as well as surgical treatment, including possible revision arthroplasty, cannot be assessed due to the absence of clinical data. Studies under controlled conditions on the possible treatment approaches in the presence of arthrofibrosis are desirable and necessary in order to be able to assess the significance of the symptoms. In addition to treatment, great importance should also be attached to the diagnostics. Histological confirmation of the diagnosis of arthrofibrosis should only be considered to a limited extent in the case of an assumed, only moderately successful surgical intervention.

In-hospital complications following total knee and hip arthroplasty in patients with human immunodeficiency virus.

OBJECTIVES: This study aims to analyze the in-hospital complication rates in patients with human immunodeficiency virus (HIV) following primary total knee (TKA) and total hip arthroplasty (THA). PATIENTS AND METHODS: This retrospective study included a total of 37 patients including 11 patients undergoing TKA (11 males; mean age: 60.8±16.0 years; range, 48 to 80 years) and 26 patients undergoing THA (23 males, 3 females; mean age: 49.9±11.5 years; range, 35 to 70 years) between January 2010 and December 2019. The patients were evaluated in terms of body mass index (BMI), American Society of Anesthesiology (ASA) scores, pre and postoperative blood tests, indications for surgery, operative time, length of hospital stay, and in-hospital complications. RESULTS: The overall in-hospital complication rate following primary TKA (n=2, 18.2%) and THA (n=2, 7.7%) was 10.8%. Following TKA, one patient had deep vein thrombosis and one patient developed acute renal failure. In the THA group, postoperative delirium and trochanteric fracture were noted. CONCLUSION: The in-hospital complication rates increased in HIV-positive patients following TKA and THA. The risk of complications can be mitigated with the aid of a better interdisciplinary cooperation and thorough surgical planning.

Enhancing the radiological classification system from the distal femur to the proximal tibia.

OBJECTIVES: This study aims to identify anatomical variants of the proximal tibia shaft and to develop a novel classification system for proximal tibia. PATIENTS AND METHODS: Between October 2019 and April 2020, a total of 200 patients with standard knee anteroposterior radiographs were included in this study. We measured the inner diameter of the tibia 16 cm distally from the tibial plateau and 3 cm distally from the tibial spine. The ratio between these two measurements was applied as the novel index ratio. RESULTS: A total number of 197 patients (100 males and 97 females) with a median age of 68 years (range, 21 to 89 years) were included in the final analysis. According to the 25th and 75th percentiles, three groups were clustered for each sex. A higher distribution of the type B pattern was found in female and male patients. However, type A with a narrow inner diaphyseal diameter was less common in female patients. The median intraobserver reliability for rater 1 was 0.998. The inter-observer reliability was high (intraclass correlation coefficient: 0.998). There was a moderate correlation between the anteroposterior (AP) diameter and height (r=0.568) and a low correlation between the AP diameter and weight (r=0.376). The novel index shows no significant correlation between the index ratio and height (r=0.082), weight (r=0.014) or body mass index (r=-0.038). CONCLUSION: The novel classification presents three different types of tibia for each sex: type C has a wider inner diaphyseal diameter compared to type A with a narrow inner diaphyseal diameter. Type B has the widest distribution among the subjects.

High revision rates following repeat septic revision after failed one-stage exchange for periprosthetic joint infection in total knee arthroplasty.

AIMS: The outcome of repeat septic revision after a failed one-stage exchange for periprosthetic joint infection (PJI) in total knee arthroplasty (TKA) remains unknown. The aim of this study was to report the infection-free and all-cause revision-free survival of repeat septic revision after a failed one-stage exchange, and to determine whether the Musculoskeletal Infection Society (MSIS) stage is associated with subsequent infection-related failure. METHODS: We retrospectively reviewed all repeat septic revision TKAs which were undertaken after a failed one-stage exchange between 2004 and 2017. A total of 33 repeat septic revisions (29 one-stage and four two-stage) met the inclusion criteria. The mean follow-up from repeat septic revision was 68.2 months (8.0 months to 16.1 years). The proportion of patients who had a subsequent infection-related failure and all-cause revision was reported and Kaplan-Meier survival for these endpoints was determined. Patients were categorized according to the MSIS staging system, and the association with subsequent infection was analyzed. RESULTS: At the most recent follow-up, 17 repeat septic revisions (52%) had a subsequent infection-related failure and the five-year infection-free survival was 59% (95% confidence interval (CI) 39 to 74). A total of 19 underwent a subsequent all-cause revision (58%) and the five-year all-cause revision-free survival was 47% (95% CI 28 to 64). The most common indication for the first subsequent aseptic revision was loosening. The MSIS stage of the host status (p = 0.663) and limb status (p = 1.000) were not significantly associated with subsequent infection-related failure. CONCLUSION: Repeat septic revision after a failed one-stage exchange TKA for PJI is associated with a high rate of subsequent infection-related failure and all-cause revision. Patients should be counselled appropriately to manage expectations. The host and limb status according to the MSIS staging system were not associated with subsequent infection-related failure. Cite this article: Bone Joint J 2022;104-B(3):386-393.

Favourable outcomes of repeat one-stage exchange for periprosthetic joint infection of the hip.

AIMS: One-stage exchange for periprosthetic joint infection (PJI) in total hip arthroplasty (THA) is gaining popularity. The outcome for a repeat one-stage revision THA after a failed one-stage exchange for infection remains unknown. The aim of this study was to report the infection-free and all-cause revision-free survival of repeat one-stage exchange, and to investigate the association between the Musculoskeletal Infection Society (MSIS) staging system and further infection-related failure. METHODS: We retrospectively reviewed all repeat one-stage revision THAs performed after failed one-stage exchange THA for infection between January 2008 and December 2016. The final cohort included 32 patients. The mean follow-up after repeat one-stage exchange was 5.3 years (1.2 to 13.0). The patients with a further infection-related failure and/or all-cause revision were reported, and Kaplan-Meier survival for these endpoints determined. Patients were categorized according to the MSIS system, and its association with further infection was analyzed. RESULTS: A total of eight repeat septic revisions (25%) developed a further infection-related failure, and the five-year infection-free survival was 81% (95% confidence interval (CI) 57 to 92). Nine (28%) underwent a further all-cause revision and the five-year all-cause revision-free survival was 74% (95% CI 52 to 88). Neither the MSIS classification of the host status (p = 0.423) nor the limb status (p = 0.366) was significantly associated with further infection-related failure. CONCLUSION: Repeat one-stage exchange for PJI in THA is associated with a favourable five-year infection-free and all-cause revision-free survival. Notably, the rate of infection control is encouraging when compared with the reported rates after repeat two-stage exchange. The results can be used to counsel patients and help clinicians make informed decisions about treatment. With the available number of patients, further infection-related failure was not associated with the MSIS host or limb status. Cite this article: Bone Joint J 2022;104-B(1):27-33.

Arthrofibrosis following primary total hip arthroplasty: a distinct clinical entity.

INTRODUCTION: Arthrofibrosis is a relatively frequent complication after total knee arthroplasty. Although stiffness after total hip arthroplasty (THA), because of formation of heterotopic ossification or other causes, is not uncommon, to the authors' best knowledge, arthrofibrosis after THA has not been described. The aim of this study is to describe the arthrofibrosis of the hip after primary THA using an established clinical and histological classification of arthrofibrosis. MATERIALS AND METHODS: We retrospectively examined all patients who were histologically confirmed to have arthrofibrosis after primary THA during revision surgery by examination of tissue samples in our clinic. Arthrofibrosis was diagnosed according to the histopathological SLIM-consensus classification, which defines seven different SLIM types of the periimplant synovial membrane. The SLIM type V determines the diagnosis of endoprosthesis-associated arthrofibrosis. RESULTS: The study population consists of 66 patients who were revised due to arthrofibrosis after primary THA. All patients had a limitation in range of motion prior to revision with a mean flexion of 90° (range from 40 to 125), mean internal rotation of 10° (range from 0 to 40) and mean external rotation of 20° (range from 0 to 50). All patients had histological SLIM type V arthrofibrosis, corresponding to endoprosthesis-associated arthrofibrosis. Histological examination revealed that seven patients (10.6%) had particle-induced and 59 patients (89.4%) had non-particle-induced arthrofibrosis. CONCLUSION: This is the first description of endoprosthetic-associated arthrofibrosis after primary THA on the basis of a well-established histological classification. Our study results could enable new therapeutic and diagnostic opportunities in patients with such an arthrofibrosis. Surgeons should keep arthrofibrosis as a possible cause for stiffness and pain after primary THA in mind. LEVEL OF EVIDENCE: Diagnostic study, Level of Evidence IV.

Standard radiological classification of glenohumeral osteoarthritis does not correlate with the complexity of the arthritic glenoid deformity.

BACKGROUND: The Samilson-Prieto classification (SPC) depending on the humeral osteophyte length on a-pX-rays today is widely used to classify glenohumeral osteoarthritis in general. For treatment planning and prognosis, the patho-morphology of the glenoid and static posterior subluxation of the humeral head classified according to Walch is of much higher importance. Here, usually a CT or MRI scan is required for a correct classification. A possible correlation between both classifications is poorly explored. Without it, the complexity of the case might be mis-interpreted using the SPC. The aim of this study was to investigate such a correlation, i.e. whether it correlates with the glenoid deformity and degree of humeral head subluxation. PATIENTS AND METHODS: Radiological datasets (X-ray and CT or MRI) of 352 patients with primary OA of the shoulder were evaluated by two observers experienced in shoulder surgery. For the Samilson-Prieto classification, true a-p shoulder radiographs and for the modified Walch classification CT or MRI scans in the axial plane were interpreted using a validated method. To investigate a correlation between both classifications, the Fisher's exact test was used. For the interobserver reliability, the weighted kappa coefficient κ was determined. RESULTS: For the Walch classification, both observers found a similar percentage for the different types, with decreasing numbers from normal (type A1) to severely altered glenoids In the Samilson-Prieto classification, OA grade I was predominant, while grade II and III showed a relatively equal distribution. Interobserver reliability was high both for the Walch classification with a κ 0.923 (95% confidence interval 0.892; 0.954) and) for the SPC with a κ 0.88 (95% confidence interval 0.843; 0.916). A correlation between the two classifications in Fischer's exact test could not be shown (p = 0.584). DISCUSSION: Since there is no correlation between both, using the Samilson-Prieto classification alone might miss relevant prognostic factors in gleno-humeral OA. Adequate imaging of the glenoid morphology also in the axial plane is absolutely mandatory to understand the complexity and chose the right treatment for each patient. LEVEL OF EVIDENCE: Study of Diagnostic Test-Level II.

[Manual addition of antibiotics to industrial bone cement mixes : Investigations of the dry mix in the cement cartridge during manual admixture to polymer-active substance mixtures]. / Manuelle Beimischung von Antibiotika zu industriellen Knochenzementmischungen : Untersuchungen zur Trockenmischung in der Zementkartusche bei der manuellen Beimischung zu Polymer-Wirkstoff-Gemischen.

BACKGROUND: Periprosthetic infection (PPI) is a rare but serious complication. An elementary component of the therapy of PPI is the use of bone cement with the addition of antibiotics. For targeted therapy, manual mixing of antibiotics with industrially produced bone cement mixtures is often necessary. Possible problems resulting from manual mixing have not been described sufficiently so far. OBJECTIVES: Therefore, the aim of the present study was to describe the influence of the additional homogenisation by dry mixing of a polymer-active substance mixture on the quality of manually added cement. MATERIAL AND METHODS: In the laboratory-based study, four cement samples were prepared using different methods for manual addition and homogenisation of antibiotics (vancomycin). The reference control was Copal® G + V (Heraeus Medical GmbH, Wehrheim, Germany), to which the vancomycin (V) had already been industrially added. The samples were then examined for mechanical, microbiological and microscopic parameters. RESULTS: In the mechanical and microbiological results, no statistically significant differences were found between the manually added mixtures and the reference. After dry mixing of the polymer powder, the inner surface of the mixing cartridges used showed signs of scratching in the microscopic examination and showed indications of abrasion during mixing. CONCLUSION: The manual addition of antibiotics to industrially produced bone cement should be reserved for selected indications if the bone cement mixtures produced by industry are not sufficient.

Risk factors for mortality following one-stage septic hip arthroplasty - a case-control study.

PURPOSE: Despite good clinical outcomes and a high success rate, there is a comparatively high mortality after one stage septic exchange of total hip arthroplasty. The aim of this study was to identify risk factors for mortality in the hospitalization period after one-stage septic exchange of THA. METHODS: We retrospectively analyzed in our database all patients who had a one-stage septic exchange for periprosthetic infection of THA and died during hospitalization (n = 33). The control group was matched semi-randomly by surgical procedure (n = 121) who did not die during hospitalization. The two groups were analyzed for risk factors such as age, Charlson Comorbidity Index (CCI), and high-/low-virulence bacteria. RESULTS: In the deceased group, 16 patients were female and 17 were male with a mean age at surgery of 73.2 years. In the control group, there were 55 females and 66 males with an average age at surgery of 68.2 years. Comparing the two groups, the deceased group had a significantly higher proportion of liver disease as well as higher rate of pulmonary embolism, apoplexy, and/or myocardial infarction, an increased CCI with an average of 6.5 and advanced age. Further demographic and surgery-related parameters especially high- or low-virulent germs were not identified as risk factors for mortality during the hospitalization period. The binominal logistic regression analysis showed that the probability of an inpatient death following one-stage septic exchange of THA increases by a factor of 3.079, with each additional point of the CCI. CONCLUSION: In conclusion, advanced age and high CCI are the main risk factors for mortality after single-stage septic change of THA. However, high-virulence bacteria have no influence on the mortality during the hospitalization period after one-stage septic exchange of THA.

Results of the first 1,000 procedures after resumption of elective orthopedic services following COVID-19 pandemic: Experiences of a high-volume arthroplasty center.

OBJECTIVES: This study aims to investigate the effectiveness of a screening questionnaire to identify high-risk patients for novel coronavirus-2019 (COVID-19) among those undergoing elective orthopedic surgery. PATIENTS AND METHODS: Between May 4th, 2020 and June 11th, 2020, a total of 1,021 consecutive patients (492 males, 529 females; mean age: 62.3±15.1 years; range, 13 to 91 years) who were scheduled for elective orthopedic surgery were included. A screening questionnaire was applied to all patients. The patients admitted to hospital were also tested for COVID-19 infection through reverse transcription-polymerase chain reaction of the nasopharyngeal swab. RESULTS: Of the patients, 1,003 (98.2%) underwent elective surgery as planned. The screening questionnaire classified 30 patients as high-risk for COVID-19. A total of 18 procedures (n=18, 1.8%) were postponed due to the high risk of possible transmission of COVID-19. None of 991 low-risk patients were tested positive for COVID-19. CONCLUSION: The use of guiding principles for resuming elective orthopedic surgery is safe without a higher risk for complications in selected cases.