Leukocyte esterase and alpha-defensin in periprosthetic joint infection: predictive quality and correlation in a prospective study.

PURPOSE: Periprosthetic joint infection (PJI) is a rare but serious complication of total joint arthroplasty (TJA). An accurate diagnosis of PJI preoperatively does not exist. Alpha-defensin (AD) is a proven and common indicator. The diagnostic marker of leukocyte esterase (LE) promises some advantages: feasibility, availability, and fast result reporting. The aim of this study was the evaluation of the predictive quality and correlation between both diagnostic tools in the diagnosis of PJI. METHODS: A prospective study was conducted between April 2018 and August 2022. All patients with suspicion of PJI on hip and knee joint were included and underwent a routine and standardized joint punction. For laboratory diagnostics of AD, the synovial liquid was analyzed by ELISA. The sample was additionally applied to a LE test strip (Combur 10 Test, Roche Diagnostics, Mannheim, Germany). RESULTS: A total of 249 patients were examined (mean age 67.12 ± 11.89; gender distribution man/woman 139 (55.8%)/110(44.2%), hip/knee 71(28.5%)/178 (71.5%). According to EBJIS criteria, PJI was diagnosed in 54 (21.7%) patients. AD showed excellent results with an AUC of 0.930 (sensitivity/specificity 0.870/0.990). LE yielded very good results with an AUC of 0.820 (sensitivity/specificity 0.722/0.918). Both parameters showed a strong positive correlation. CONCLUSION: LE is a rapidly available alternative in PJI diagnostics. The simultaneous determination of both markers may enhance diagnostic reliability. A routine usage may shorten the time from diagnosis to treatment of PJI.

Risk of Periprosthetic Joint Infection after Posttraumatic Hip Arthroplasty following Acetabular Fractures.

BACKGROUND: Raised complication rates have been reported for total hip arthroplasty (THA) in posttraumatic hip joints after acetabular fractures with prior open reduction and internal fixation (ORIF). The present study evaluated (I) postoperative surgical site infection and the risk of early infection following THA in posttraumatic hip joints after acetabular fractures and (II) the discriminatory ability of preoperative C-reactive protein (CRP) blood levels for periprosthetic joint infection (PJI). MATERIALS AND METHODS: Patients were included who had undergone THA (2014-2019) after prior ORIF, and nonsurgically treated acetabular fractures. Patients' demographics and the duration between fracture and THA implantation were assessed. Preoperative diagnostic testing (laboratory results, hip aspirations) as well as the results of intraoperative microbiological swabs and sonication were also evaluated. Postoperative complications were recorded. RESULTS: Sixty-seven patients (51 men/16 women) were included, with a mean age of 54.7 ± 14.0 years (range: 18.0-82.9). The mean time between acetabular fracture and THA was 13.5 ± 14.9 years (0.2-53.5). Four subgroups were classified: subgroup I (nonsurgical, n = 15), subgroup II (complete removal of osteosynthesis, n = 8), subgroup III (partial removal of osteosynthesis, n = 15), and subgroup IV (remaining osteosynthesis, n = 29). Preoperative CRP blood levels were normal. CRP levels had no discriminatory ability to predict PJI (AUC: 0.43). Positive microbiological swabs were assessed in subgroups III (n = 1) and IV (n = 2). Complications during follow-up occurred in subgroups I (one aseptic loosening [6.7%]), III (one wound revision [6.7%], two low-grade infections [13.3%]), and IV (three low-grade infections [10.3%]). CONCLUSION: High infection rates were found in patients with THA after acetabular fracture with remaining implants or partial implant removal. Serum CRP alone seems to be a poor predictor. Therefore, an extensive diagnostic algorithm can help to detect an occult infection, including preoperative hip aspiration (microbiological samples and measurements of synovial CRP, WBC, and alpha-defensin levels). Intraoperative tissue samples and sonication results should be obtained during THA implantation.

Evaluation of modified and newly applied patella height indices in primary total knee arthroplasty.

OBJECTIVE: The aim of this radiological study was to compare several relevant modified and newly applied patella height indices (PHI) in navigated primary total knee arthroplasty (TKA) to determine intra- and interobserver reliability in order to give a recommendation for clinical application in measuring patella height (PH) in primary TKA. MATERIALS AND METHODS: A retrospective data analysis assessing different PHI (modified Insall-Salvati index (mISI), Caton-Deschamps index (mCDI), Blackburne-Peel index (mBPI), Plateau-Patella Angle (mPPA); Miura-Kawaramura index (MKI), Knee-Triangular index (KTI)) on lateral knee radiographs was performed by two blinded observers using the same software three months pre- and postoperatively. Concordance correlation coefficient and Pearson's correlation respectively were determined for intra- and interobserver rating as well as a categorization according to Landis and Koch and Cohen. RESULTS: A total of 337/291 patients of a 5-year period could be analyzed pre-/postoperatively. Excellent postoperative interrater results according to the categorization of Landis and Koch were achieved for the mBPI (Pearson 0.98) > mPPA (0.90) > KTI (0.86), good results for the MKI (0.79) and the mCDI (0.69), and moderate results for the mISI (0.52) with a predominantly strong Cohen correlation in almost all cases. Preoperatively, the mBPI and the KTI were the best interrated PHI. No PH changes could be found postoperatively for the mISI, KTI, MKI, and mPPA. CONCLUSION: The mBPI, the mPPA, and the KTI can be recommended for PH assessment in TKA. The mPPA might be the easiest one to use in a daily clinical set-up.

Hip Revision Arthroplasty of Periprosthetic Fractures Vancouver B2 and B3 with a Modular Revision Stem: Short-Term Results and Review of Literature.

BACKGROUND: Periprosthetic fractures Vancouver type B2/B3 after total hip arthroplasty (THA) is a challenging entity with increasing numbers. Limited data are available for this type of fracture treated with modular stems. Therefore, this study evaluated the outcome of Vancouver type B2/B3 fractures treated with a modular hip revision stem using a subproximal/distal anchorage and compared it to the current literature. MATERIALS AND METHODS: A consecutive series of periprosthetic Vancouver type B2/B3 fractures treated with a modular revision stem was retrospectively (2013 - 2016) evaluated. Assessment included the clinical (HHS, pain, ROM) as well as the radiological outcome (subsidence, loosening, facture healing). In adddition, the surgical technique is described in detail and results are compared with the current literature. RESULTS: A total of 18 patients (female/male 12/6) with Vancouver B2/B3 (n = 12/6) fractures with a mean age of 75.5 (60 - 89) years were included. The revision stem was inserted via a modified transgluteal approach (n = 16) or classical transfemoral approach (n = 2). The mean follow-up was 18.5 months, with a mean Harris Hip Score of 72.5 ± 18.7 (35.0 - 99.0) points. The fracture healing rate was 94.4% (n = 17) with osseous integration according to Engh in all cases. Dislocations of the greater trochanter were recorded in seven patients (38.9%). According to Beals and Towers, all results were rated excellent or good. No implant-related failure or relevant subsidence during this time was observed. Major complications were observed in five patients with two periprosthetic joint infections and two cases of major revision surgery. CONCLUSION: This study assessing Vancouver B2/3 fractures shows reproducible, good, short-term results in terms of subsidence and clinical functional outcome by the use of a modular revision stem. The transfemoral approach together with the modular stem allows for a stable fixation and good fracture healing. However, our data and review of the literature also documents the difficulties and higher complication rate associated with Vancouver B2/3 fractures.

Pronounced Heterotopic Ossifications after Traumatic Hamstring Rupture: Is an Ossification Prophylaxis Useful? / Ausgeprägte heterotope Ossifikationen nach traumatischer Ruptur der ischiokruralen Muskulatur: Ist eine Ossifikationsprophylaxe sinnvoll?

Hamstring injuries include a wide range of injuries and affect mainly athletes with high eccentric loads (football, athletics, rugby, climbing). According to the latest literature, unrecognized traumatic ruptures can cause permanent discomfort and may be associated with a poorer postoperative outcome when delayed surgical therapy is performed. Heterotopic ossifications (HO) after hamstring rupture have been described in individual case reports and smaller studies so far. Heterotopic ossifications are mainly known in hip surgery and elbow fractures. In this case report, a 48-year-old patient presented with an increasing swelling with hardening in the area of the right ischial tuberosity. One year before, an impact trauma was the reason for a traumatic hamstring rupture which was diagnosed with a delay. The HO was excised and the tendon refixed with two suture anchors. By limiting the range of motion with a hip-knee orthosis for 9 weeks, a regular postoperative healing process was observed. Heterotopic ossifications after hamstring ruptures have been reported repeatedly but have not been evaluated in any major study so far. It should therefore be considered whether prophylaxis with NSAIDs should be used for conservatively and surgically treated hamstring ruptures, analogous to the ossification prophylaxis for hip endoprostheses or fractures in the elbow region.

A Modified Rotator Cuff Sparing Approach to the Proximal Humerus in Antegrade Nail Osteosynthesis with Transosseous Supraspinatus Tendon Refixation. / Ein modifizierter, die Rotatorenmanschette schonender Zugang zum proximalen Humerus bei antegrader Marknagelosteosynthese mit transossärer Supraspinatussehnenrefixation.

BACKGROUND: Due to the approach within antegrade humerus nail osteosyntheses, lesions of the supraspinatus tendon with a consecutive functional limitation of the rotator cuff (RC), insufficiencies, adhesions and chronic shoulder pain in the long term can result. The evidence respectively the study data situation is limited regarding the evaluation of this issue. PATIENTS/MATERIAL AND METHODS: We are the first to present by means of a case report with a geriatric female patient and a dislocated diaphyseal humerus fracture a rotator cuff sparing osseous approach to the proximal humerus in antegrade nail osteosynthesis without harming the vulnerable supraspinatus tendon (SSP). This is possible through a limited osteotomy of the greater tubercle with the preparation of a 10 mm deep and 15 to 20 mm wide osseous SSP base. The medullary cavity is then opened for inserting the nail in an antegrade manner and closed after fracture stabilization through reposition of the attached osteotomy of the greater tubercle by means of a suture anchor, for example. The procedure also includes a biceps tenodesis. Besides the description of the intraoperative approach and procedure, the clinical and functional results were recorded by established scores as well as radiologically respectively sonographically 6 weeks (T1) and 3 months (T2) postoperatively. RESULTS: The patient was very satisfied regarding pain and function after the modified operative procedure. The rotator cuff tests were negative and there were no impingement like symptoms or indications for an adhesive capsulitis. Range of motion as well as the Constant and (Quick) DASH-Score showed a very good function in the course. The implant was located regularly in the radiological control and the fracture showed a good osseous consolidation. A bland joint without effusion or periarticular fluid and no adhesion with the delta fascia could be presented by sonography. The RC and especially the SSP showed a normal sonographic separation. The functional results are comparable to the other publications so far. CONCLUSION: The described surgical technique shows a significantly less invasive approach for the implantation of an antegrade humerus nail in the case of a humerus shaft fracture with an excellent function of the affected shoulder in a short-term follow-up. This novel approach should be evaluated by means of prospective studies regarding the functional outcome to justify the establishment of this modified procedure in the long term. Other modified approaches have been depicted but are essentially differing from our described procedure with regards to the invasiveness of the vulnerable tendinous structure of the SSP respectively RC.

The elastic capacity of a tendon-repair construct influences the force necessary to induce gapping.

PURPOSE: Most biomechanical investigations of tendon repairs were based on output measures from hydraulic loading machines, therefore, accounting for construct failure rather than true gapping within the rupture zone. It was hypothesized that the elastic capacity of a tendon-repair construct influences the force necessary to induce gapping. METHODS: A tendon-repair model was created in 48 porcine lower hind limbs, which were allocated to three fixation techniques: (1) Krackow, (2) transosseous and (3) anchor fixation. Loading was performed based on a standardized phased load-to-failure protocol using a servohydraulic mechanical testing system MTS (Zwick Roell, Ulm, Germany). Rupture-zone dehiscence was measured with an external motion capture device. Factors influencing dehiscence formation was determined using a linear regression model and adjustment performed as necessary. A 3-mm gap was considered clinically relevant. Analysis of variance (ANOVA) was used for comparison between groups. RESULTS: The elastic capacity of a tendon-repair construct influences the force necessary to induce gapping of 3 mm (F3mm) [ß = 0.6, confidence interval (CI) 0.4-1.0, p < 0.001]. Furthermore, the three methods of fixation did not differ significantly in terms of maximum force to failure (n.s) or F3mm (n.s). CONCLUSION: The main finding of this study demonstrated that the higher the elastic capacity of a tendon-repair construct, the higher the force necessary to induce clinically relevant gapping. LEVEL OF EVIDENCE: Controlled biomechanical study.

Improved results of ACL primary repair in one-part tears with intact synovial coverage.

PURPOSE: It was the aim to assess the influence of synovial sheath disruption on early failure of primary anterior cruciate ligament (ACL) repair. It was hypothesized that more-part ACL tears with disruption of the synovial sheath are associated with a higher risk of failure after primary ACL repair. METHODS: A cohort study was conducted comprising patients with primal ACL tears undergoing primary ACL repair and dynamic intraligamentary stabilization (DIS). The patients were stratified into three groups: A-one-part rupture with intact synovial membrane (n = 50), B-two-part ruptures resultant to separation of the ACL into two main bundles with synovial membrane tearing (n = 52) and C-more parts involving multilacerated ruptures with membrane disruption (n = 22). Failure was defined as a retear or residual laxity (anterior posterior translation > 5 mm compared to healthy knee). Adjustment for potential risk factors was performed using a multivariate logistic-regression model. RESULTS: The overall failure rate was 17.7% throughout the mean follow-up period of 2.3 ± 0.8 years. The failure rate in patients with one-part ACL tears with an intact synovial membrane was 4% (n = 2) (Group A), which was significantly lower than the failure rates in groups B and C, 26.9% (n = 14) (p = 0.001) and 27.3% (n = 6) (p = 0.003), respectively. Disruption of the synovial sheath in two- or more-part tears was identified as an independent factor influencing treatment failure in primary ACL repair (OR 8.9; 95% CI 2.0-40.0). CONCLUSION: The integrity of the ACL bundles and synovial sheath is a factor that influences the success of ACL repair. This needs to be considered intra-operatively when deciding about repair. LEVEL OF EVIDENCE: IV.

Periprosthetic tibial fractures in total knee arthroplasty - an outcome analysis of a challenging and underreported surgical issue.

BACKGROUND: Periprosthetic fractures after total knee arthroplasty (TKA) are an increasing problem and challenging to treat. The tibial side is commonly less affected than the femoral side wherefore few studies and case reports are available. The aim of this study was to analyze the outcome of periprosthetic tibial fractures and compare our data with current literature. METHODS: All periprosthetic tibial TKA fractures that were treated at our Level 1 Trauma Center between 2011 and 2015 were included and analyzed consecutively. The Felix classification was used to assess the fracture type and evaluation included the radiological and clinical outcome (Knee Society Score/KSS, Oxford Knee Score/OKS). RESULTS: From a total of 50 periprosthetic TKA fractures, 9 cases (7 female, 2 male; 2 cruciate retaining, 7 constrained TKAs) involving the tibial side were identified. The mean age in this group was 77 (65-85) years with a follow-up rate of 67% after a mean of 22 (0-36) months. The Felix classification showed type IB (n = 1), type IIB (n = 2), type IIIA (n = 4) and type IIIB (n = 2) and surgical intervention included ORIF (n = 6), revision arthroplasty (n = 1), arthrodesis (n = 1) and amputation (n = 1). The rate of adverse events and revision was 55.6% including impaired wound healing, infection and re-fracture respectively peri-implant fracture. Main revision surgery included soft tissue surgery, arthrodesis, amputation and re-osteosynthesis. The clinical outcome showed a mean OKS of 29 (19-39) points and a functional/knee KSS of 53 (40-70)/41 (17-72) points. Radiological analyses showed 4 cases of malalignment after reduction and plate fixation. CONCLUSIONS: Periprosthetic tibial fractures predominantly affect elderly patients with a reduced bone quality and reveal a high complication rate. Careful operative planning with individual solutions respecting the individual patient condition is crucial. If ORIF with a plate is considered, restoration of the correct alignment and careful soft tissue management including minimal invasive procedures seem important factors for the postoperative outcome.

Interview based malnutrition assessment can predict adverse events within 6 months after primary and revision arthroplasty - a prospective observational study of 351 patients.

BACKGROUND: Being at risk for malnutrition can be observed among hospitalized patients of all medical specialties. There are only few studies in arthroplasty dealing with defining and assessing malnutrition as such a potentially risk. This study aims to identify the risk for malnutrition following primary (pAP) and revision arthroplasty (rAP) (1) using non-invasive interview based assessment tools and to analyze effects on clinical outcome (2) and quality of life (3). METHODS: A consecutive series of hospitalized patients of a Department of Arthroplasty at a Level 1 Trauma Center in Western Europe was observed between June 2014 and June 2016. Patients were monitored for being at risk for malnutrition at hospital admission (T1) and 6 months post surgery (T2) by non-invasive interview based assessment tools (NRS 2002, SF-MNA, MNA). Adverse events, length of hospital stay and quality of life (HRQL, SF-36) were monitored. RESULTS: 351 (283 pAP/ 68 rAP) patients were included. At T1, 13.4% (47) / 23.9% (84) / 27.4% (96) and at T2 7.3% (18) / 17.1% (42) / 16.0% (39) of all patients were at risk for malnutrition regarding NRS/SF-MNA/MNA. Prevalence of malnutrition risk was higher in rAP (22.1-29.4%) compared to pAP (11.3-26.9%). Patients being at risk for malnutrition showed prolonged hospitalization (NRS 14.5 to 12.5, SF-MNA 13.7 to 12.4, MNA 13.9 to 12.3 days, p < 0.05), delayed mobilization (NRS 2.1 to 1.7, SF-MNA 1.8 to 1.7, MNA 1.9 to 1.7 days), lower values in HRQL and more adverse events. CONCLUSIONS: There is a moderate to high prevalence of risk for malnutrition in arthroplasty that can easily be assessed through interview based screening tools. Being at risk for malnutrition can reduce the clinical outcome following pAP and rAP. Patients with an impaired nutritional status show reduced values in physical and mental aspects of HRQL. Non-invasive interview-based nutritional assessment can predict adverse events in primary and revision total arthroplasty and can therefore help identifying patients at risk before surgery. TRIAL REGISTRATION: The study protocol was approved by the local ethics committee (193/2014BO2) and registered at the German Clinical Trials Register according to WHO standard ( DKRS00006192 ).

Adverse Events in the Treatment of Periprosthetic Fractures Around the Knee - a Clinical and Radiological Outcome Analysis. / Komplikationen in der Behandlung periprothetischer Frakturen bei einliegender Knietotalendoprothese ­ eine klinisch-radiologische Outcome-Analyse.

BACKGROUND: The incidence of periprosthetic fractures associated with total knee arthroplasty (PpFxK) has been reported to be 0.3 - 5.5%. 40% of all cases are related to revision TKA. The most common localisation is the distal femur. Classification is performed according to Rorabeck (RB). RB I - II fractures are usually treated with locked plating and retrograde intramedullary nailing, whereas RB III fractures are an indication for revision arthroplasty using a hinged endoprosthesis. PpFxK of the patella can be classified according to Goldberg and PpFxK of the proximal tibia can be grouped as in Felix. Interprosthetic fractures can be regarded as a special type of PpFx. Due to the increasing numbers of TKA being performed, increasing numbers of adverse events in arthroplasty can be expected. Adverse events in the treatment of PpFxK occur in up to 41% of patients according to the literature and revision is needed in approximately 29% of all cases. Risk factors are age, osteoporosis, infection, malalignment, osteolysis/loosening of the implant and status post revision. PATIENTS: A clinical and radiographic follow-up was performed with 50 patients (14 men, 36 women) treated for PpFxK of the femur, tibia and patella between 2011 and 2015 at the department of arthroplasty at a level 1 trauma center in Europe. RESULTS: The follow-up of all patients was 68%, with an average of 19.1 ± 14.6 (1 - 49) months between PpFxK and clinical follow-up. 16% of the patients were allocated for further treatment or revision surgery from other hospitals. The patients' median age was 78.0 ± 8.8 (55 - 94) years. Most patients were affected by several orthopaedic and internal medical comorbidities. PpFxK classified as RB II were the most common fractures (60%, n = 30). PpFxK usually occurred 5.0 ± 4.8 (0 - 20) years after index TKA (primary or revision TKA), mostly in patients with CR-retaining endoprosthesis, whereas PpFxK according to Felix occurred significantly earlier and mostly in hinged TKAs. Patients achieved on average a mean Oxford Knee Score of 31.1 ± 9.9 (14 - 46) points. The functional Knee Society Score (KSS) was 52.6 ± 24.4 (20 - 100) and the mean KSS was 58.7 ± 26.8 (0 - 99) points (n = 25). Radiographic evaluation of the RB I - II patients showed frontal and sagittal malalignment in 20.6% of all cases after reduction and plate fixation. The overall rate of surgical adverse events was 50%; 44% of all RB patients needed revision surgery. Adverse events comprised non-union, failure of osteosynthesis, infection, wound healing disorders and re-fractures in the RB II and the Felix subgroup. CONCLUSION: PpFxK are severe injuries and are associated with a high rate of adverse events related to treatment. Patients often have a complex background and a history of revision surgery or periprosthetic joint infection. The treatment of PpFxK should therefore take place at a centre with expertise in traumatology as well as in revision arthroplasty. Preoperative infection diagnostic testing as well as adequate imaging (X-rays and CT) are essential. We furthermore advise early evaluation of revision arthroplasty, especially in elderly patients suffering from PpFxK with insufficient bone quality around the TKA and closeness between fracture and TKA. In the case of plate fixation, it is important to give attention to correct reduction - to prevent non-union, loosening of the implant and failure of the osteosynthesis - as well as to consider double plating.

[Implantation of a Modular Distal Femoral Replacement with Compressive Osseointegration as a Salvage Procedure in a Complex Femoral Posttraumatic Setting]. / Implantation einer modularen Knietotalendoprothese mit distalem Femurersatz mit kompressiver Osteointegration als Rückzugsoption bei komplexer femoraler posttraumatischer Ausgangssituation.

BACKGROUND: Large bone defects and losses play a crucial role in both tumour surgery and in complex primary and revision total knee replacement. The established options of cemented or uncemented long intramedullary stems are limited by large bone defects and are at risk from relatively high exposure to aseptic loosening. There is no general valid agreement on implant fixation of the distal femur. A further option is the cementless fixation method with compressive osseointegration, based on the so-called Wolff law of bone remodelling. This method was developed in order to reduce the high loosening rates in revision arthroplasty due to intense stress shielding and is intended to be applied in patients with huge bone losses. The so-called Compress® system (or CPS) allows such a distal femur reconstruction. It has mainly been applied and evaluated in tumor endoprosthetics. There are currently few data on the application of this system in complex distal femoral posttraumatic deformity or revision arthroplasty. PATIENTS: A case report of two male patients aged 59/56 years with a 1-year follow-up is presented. Both patients had a complex post-traumatic femoral deformity with bone loss, prior surgery and an ipsilateral hip replacement. Implantation was performed of a modular total knee replacement, consisting of a cemented modular tibia base plate and distal femoral replacement with cementless implant fixation by compressive osseointegration. Both patients were clinically and radiologically evaluated prospectively. RESULTS: Good clinical and radiological results were demonstrated in both patients after distal femoral replacement by compressive osseointegration. There was no need for further or revision surgery. Both patients were rapidly able to resume their jobs. The survival rates for CPS were comparable to published values with conventional procedures. There are yet no long-term results or extensive data for revision arthroplasty or posttraumatic cases. CONCLUSIONS: Besides distal femoral replacement with compressive osseointegration in oncological arthroplasty, the indication of complex distal femoral settings with large bone defects can be evaluated for daily clinical routine. Especially if there is ipsilateral total hip replacement, this option might be used to avoid interprosthetic stress risers.