Bilateral simultaneous knee arthroplasty shows comparable early outcome and complication rate as staged bilateral knee arthroplasty for patients scored ASA 1-3 if performed by a high-volume surgeon: a retrospective cohort study of 127 cases.

BACKGROUND AND PURPOSE: The study compares early outcomes after simultaneous and staged knee arthroplasty in patients with bilateral knee osteoarthritis (OA) to evaluate whether simultaneous bilateral TKA shows comparable early outcomes and complication rates to staged bilateral TKA. METHODS: A retrospective cohort study including all patients scheduled for primary TKA for bilateral knee OA (n = 127) was conducted. Patients received either simultaneous (n = 53, 41.7%) or staged (n = 74, 58.3%) bilateral TKA by a single, high-volume surgeon-depending on their individual preference. Demographic data, haemoglobin drop (Hb), length of stay (LOS), operation time, 30-day complication rate and achievement of rehabilitation key points were evaluated. RESULTS: There was no difference between the groups concerning age, sex, BMI or complication rate. ASA scoring was better in the simultaneous group [2.2, (15.1% ASA 1, 49.1% ASA 2, 35.8% ASA 3) vs. 2.4 (2.7% ASA 1, 51.4% ASA 2, 45.9% ASA 3)]. Average LOS was 7.8 ± 2.1 days for simultaneous TKA, 7.4 ± 1.7 days for single procedure of staged group (p < 0.453) and 14.7 ± 3.1 days if combined (p < 0.001). Cumulative Hb loss was significantly higher in the staged group (3.8 ± 1.2 g/dl vs. 2.4 ± 0.8 g/dl, p < 0.001). Detailed comparison of early outcome parameters between staged and simultaneous procedure depending on ASA score only revealed slightly slower assessment of stairs (p < 0.001) and increased Hb drop per surgery in case of simultaneous procedure (p < 0.011) if ASA score was ≥ 2. Only patients scored ASA 3 demonstrated a significant longer LOS per procedure in simultaneous group (8.5 ± 2.4 vs.7.3 ± 1.6 days, p = 0.034). INTERPRETATION: Simultaneous bilateral TKA results in comparable early outcome and complication rate than staged bilateral procedure-even for patients scored ASA 3. LEVEL OF EVIDENCE: Level IV.

Bilateral simultaneous hip arthroplasty shows comparable early outcome and complication rate as staged bilateral hip arthroplasty for patients scored ASA 1-3 if performed by a high-volume surgeon.

PURPOSE: The aim of this study was to compare early outcomes after simultaneous and staged hip arthroplasty (THA) in patients with bilateral symptomatic pathology. METHODS: We conducted a retrospective cohort study including all patients scheduled for primary THA for bilateral hip osteoarthritis (OA, n = 290). Patients either received simultaneous (n = 152, 52.4%) or staged (n = 138, 47.6%) bilateral THA based on individual preference. All operations (n = 428) were performed by one single, high-volume surgeon. Demographic data (e.g., age, ASA score) as well as perioperative parameters (haemoglobin drop (Hb), red blood cell transfusion, length of stay (LOS), operation time, six week complication rate and achievement of inpatient rehabilitation key points) were evaluated. RESULTS: Patients in the simultaneous bilateral THA group were younger (62.8 ± 8.9 vs. 65 ± 9.7 years, p = 0.022) and had lower ASA scores (1.8, (34.2% ASA 1, 55.3% ASA 2, 37.2% ASA 3) vs. 2.0 (18.8% ASA 1, 61.6% ASA 2, 19.6% ASA 3)) than the staged group. While the average LOS was 7.1 ± 1.7 days for simultaneous bilateral THA, the combined LOS for the staged group was 12.9 ± 2.4 days (p < 0.001). The cumulative operation time in the simultaneous bilateral THA group was 61.1 ± 11.5 min and 57.6 ± 7.3 min in the staged group (p < 0.015). Cumulative Hb loss was significantly higher in the staged group (2.1 ± 7.2 g/dl vs. 3.7 ± 1.3 g/dl, p < 0.001). No significant differences were found concerning the complication rate or early inpatient rehabilitation. CONCLUSION: Simultaneous bilateral hip arthroplasty in patients with symptomatic bilateral hip osteoarthritis is as safe and successful as a staged procedure if performed by a high-volume surgeon.

Modern Total Knee Arthroplasty (TKA): With Or Without a Tourniquet?

BACKGROUND: Since arthritis of the knee is one of the most common pathologies in industrialized nations, there has been a growing interest in fast-track total knee arthroplasty (TKA). However, while one of the main concerns is the role of a tourniquet, the available data are inconclusive. AIM: This study sought to assess the link between postoperative outcomes and use of a tourniquet in TKA. Our goal was to determine whether it is justified to forego tourniquet use as indicated by the fast-track concept. METHODS: The participants (n = 108) in this retrospective, non-randomized study were assigned into two groups after they satisfied the inclusion criteria: primary gonarthrosis or secondary gonarthrosis without previous arthrotomy. TKA was performed without (Group I, n = 55) or with (Group II, n = 53) a tourniquet. The postoperative outcome was evaluated in terms of postoperative pain, based on a numeric rating scale (NRS) and the need for pain medication, and postoperative function, based on range of motion (ROM) and walking tests. RESULTS: Overall, no significant correlations were observed between tourniquet use and postoperative pain according to the NRS. Group I required less oxycodone, but more non-opioids. There was no significant difference in the improvement in pre- to postoperative ROM with regard to tourniquet use. The final walking distance was significantly longer in Group I. CONCLUSIONS: These results suggest that there is no strongly significant link between the postoperative outcome and the use of a tourniquet. However, further studies will be needed to determine whether a tourniquet may have some other impact on TKA.

Single-Bundle Versus Double-Bundle Anterior Cruciate Ligament Reconstruction-5-Year Results.

PURPOSE: To compare anatomic single-bundle (SB) with double-bundle (DB) anterior cruciate ligament reconstruction (ACL-R) and to evaluate the respective clinical outcome results. METHODS: In a prospective randomized study, 64 patients were included and separated into 2 groups. Anatomic SB and DB ACL-Rs were performed with hamstring tendons. Five years after surgery, the follow-up (FU) examination comprised International Knee Documentation Committee (IKDC) 2000, Laxitester (ORTEMA Sport Protection, Markgroeningen, Germany) measurement, and radiograph evaluation. Power calculation was performed to achieve a 95% confidence interval and 80% power on the base of 7-point IKDC subjective difference between the groups. RESULTS: A total of 53 patients (83% FU) were examined at 63.2 ± 4.7 months after surgery: 28 patients in the DB group and 25 patients in the SB group. IKDC subjective (SB: 92.8 ± 6.2, DB: 91.6 ± 7.1; P = .55) and objective scores (grade A SB/DB 20%/25%, B SB/DB 72%/57%, C SB/DB 8%/18%, D SB/DB 4%/0%; P = .45) showed no differences comparing both groups. The Laxitester measurements showed no significant difference in regard to anterior-posterior translation in neutral, internal, and external rotation or to rotation angles (P = .79). No difference was seen between the groups regarding osteoarthritic changes and tunnel widening. CONCLUSIONS: At the 5-year FU, no advantage for either the DB or SB technique in ACL-R can be seen with regard to patient-related and objective outcome measures. LEVEL OF EVIDENCE: Level I, prospective randomized controlled clinical trial.

Long-term Results of Arthroscopic Arthrolysis for Arthrofibrosis After Anterior Cruciate Ligament Reconstruction.

PURPOSE: The current study was conducted to evaluate the long-term clinical and radiological outcomes after arthroscopic arthrolysis for arthrofibrosis after anterior cruciate ligament reconstruction (ACLR). METHODS: All patients treated with arthrolysis between 1990 and 1998 were included. Indication was arthrofibrosis in at least one knee compartment or a cyclops syndrome limiting range of motion (ROM) by > 5° of extension deficit and 15° of flexion deficit. International Knee Documentation Committee (IKDC) 2000 subjective and objective, Lysholm score, and x-ray evaluation were documented. Statistical analysis and power calculation were performed (P < .05). RESULTS: One hundred forty-one patients (follow-up, 71%) were examined at a mean of 18.7 ± 2.6 years after arthroscopic arthrolysis. Mean IKDC 2000 score was 79.49 ± 14.32. IKDC objective was normal in 0%, nearly normal in 6%, abnormal in 56%, and severely abnormal in 38%. One hundred percent of patients showed more than grade II osteoarthritis. ROM improvement after arthrolysis did not change significantly compared with midterm results (t = 4.5 years). Patients with persisting motion deficits (P = .02) and after medial meniscus resection (P < .001) at time of ACLR showed significantly greater progression of osteoarthritis in comparison with patients without these additional disorders. In case of arthrolysis later than 1 year after ACLR, a more severe osteoarthritis grade (4% vs 20% grade III; P = .038) and a lower jump distance (IKDC: 61% A, 25% B vs 39% A, 41% B; P = .028) were obvious compared with patients who underwent arthrolysis within the first year after ACLR. CONCLUSIONS: Long-term motion improvement can be achieved by arthrolysis. Persistent loss of motion resulted in a higher degree of osteoarthritis in the study population. Early intervention seems advisable as patients with arthrolysis later than 1 year after index surgery reached worse IKDC objective grading. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

Influence of the tourniquet on tibial cement mantle thickness in primary total knee arthroplasty.

PURPOSE: The purpose of the study was whether the use of a tourniquet increases cement mantle thickness in primary total knee arthroplasty and influences the calculated blood loss and postoperative pain. METHODS: Ninety patients with a primary total knee arthroplasty (TKA) were enroled in this prospective randomised trial and divided into a group with (n = 45) and without tourniquet (n = 45). The radiological tibial cement mantle thickness was evaluated postoperatively in four zones on anteroposterior and two zones on lateral radiographs, and values were cumulated. Additionally, the calculated blood loss and postoperative pain levels were recorded. RESULTS: There was a median cumulative cement mantle thickness of 13 mm (range 8-19 mm) without tourniquet and of 14.2 mm (range 9-18 mm) with tourniquet (p = 0.009). The median calculated blood loss was 0.6 L (range 0.2-2.0 L) without and 0.9 L (range 0.3-1.5 L) (p = 0.02) with tourniquet. Patient-reported postoperative pain levels were significantly higher in the tourniquet group during mobilisation (p = 0.01) and at rest (p = 0.001). CONCLUSIONS: The use of a tourniquet in primary TKA increased the tibial cement mantle thickness but also increased the postoperative calculated blood loss and postoperative pain. Surgeons might take this into consideration for decision-making whether to use a tourniquet during TKA. LEVEL OF EVIDENCE: II.

Fixation of stem in revision of total knee arthroplasty: cemented versus cementless-a meta-analysis.

PURPOSE: Revision of total knee arthroplasty (TKA) is growing rapidly all over the world. The introduction of intramedullary stems for additional stability in revision is well accepted by most of the surgeons, while the philosophy of stem fixation is still under controversy. A meta-analysis was performed to compare the survivorship of revised implants with regard to a cemented or cementless stem fixation. METHODS: Publications with patients who underwent revision TKA with minimum 24-month follow-up were systematically reviewed. Type of intramedullary stem fixation, failure rate for any reason, incidence of aseptic loosening and infection were extracted with follow-up interval specified. Random-effects meta-analysis was used to aggregate incidence data, which was compared between different fixation groups by fitting of logistic regression model. RESULTS: Seventeen observational studies were included in this meta-analysis. There was a similar likelihood of failure for any reason (risk ratio, RR 0.97), general reoperation (RR 1.02), aseptic loosening (RR 1.0) and infection (RR 1.0) in cemented stem fixation group compared to cementless stem fixation group with follow-up <60 months. When follow-up period extend to more than 60 months, the same likelihood was observed as 0.98, 0.96, 0.97 and 0.98, respectively. There was no significant difference in any of these comparisons of survival-related indices. CONCLUSION: There was no significant difference in failure for any reason, reoperation, aseptic loosening and infection between revision TKA with cemented or cementless stem fixation. Based on the available literature, no superiority of any type of stem fixation was found. If follow-up period was neglected, aseptic loosening would be the leading reason for pain and dysfunction of patient undertaken revision TKA. LEVEL OF EVIDENCE: Systematic review of Level IV, Therapeutic studies, Level IV.

Rotational laxity and collateral ligament laxity following total knee arthroplasty with rotating platform.

PURPOSE: The aim of this study was to evaluate laxity in knees with pre-operative (preop) valgus alignment compared to knees with pre-operative varus alignment after total knee arthroplasty (TKA). METHODS: This was a retrospective study including 81 patients, with six years follow-up, for pre-operative valgus- or varus alignment of the leg. All patients had been supplied with the same cruciate retaining (CR) TKA with rotating platform. Clinical findings were assessed by KSS, OKS and IKDC 2000 score. Rotational knee laxity was evaluated by a validated instrument (Laxitester®) with 2 Nm torque in 30° flexion. Collateral ligament laxity was tested manually in 30° flexion with a bending moment of approximately 5 Nm. Biomechanical results were compared to the contralateral side. RESULTS: Thirty-one patients had a preop valgus alignment of 8.96° and 50 patients a varus leg axis of 4.99° in the mean. In the preop valgus knees rotational analysis showed an increased laxity of 10.7° compared to preop varus knees (p = 0.001). There was no significant difference in medial (valgus 2.6 mm, varus 2.5 mm) and lateral (valgus 2.8 mm, varus 2.7 mm) laxity. KSS and OKS showed no significant differences in the follow-up results. In the IKDC 2000 objective score 50 % of the preop varus knees and 25.8 % of the preop valgus knees were classified as nearly normal. The difference in the IKDC objective was highly significant (p < 0.001). CONCLUSION: Preop valgus knees show a significantly increased rotational laxity but no increased collateral ligament laxity compared to pre-operative varus knees six years after TKA with rotating platform. There is a significant difference in IKDC objective.

Reconstruction of Paprosky IIIB acetabular defects with porous tantalum shells and augments using the footing technique.

Aims: The use of a porous metal shell supported by two augments with the 'footing' technique is one solution to manage Paprosky IIIB acetabular defects in revision total hip arthroplasty. The aim of this study was to assess the medium-term implant survival and radiological and clinical outcomes of this technique. Methods: We undertook a retrospective, two-centre series of 39 hips in 39 patients (15 male, 24 female) treated with the 'footing' technique for Paprosky IIIB acetabular defects between 2007 and 2020. The median age at the time of surgery was 64.4 years (interquartile range (IQR) 54.4 to 71.0). The median follow-up was 3.9 years (IQR 3.1 to 7.0). Results: The cumulative medium-term survival of the acetabular construct was 89%. Two hips (5.1%) required further revision due to shell loosening, one hip (2.6%) due to shell dislocation, and one hip (2.6%) due to infection. The median Harris Hip Score improved significantly from 47 points (IQR 41.5 to 54.9) preoperatively to 80 points (IQR 73.5 to 88.6) at the latest follow-up (p < 0.001). Conclusion: The reconstruction of Paprosky IIIB acetabular defects with porous tantalum shells and two augments using the 'footing' technique showed excellent medium-term results. It is a viable option for treating these challenging defects.

Evidence-based and Patient-centered Indication for Knee Arthroplasty - Update of the Guideline. / Evidenzbasierte und patientenorientierte Indikationsstellung zur Knieendoprothese ­ Update der Leitlinie.

Knee arthroplasty is one of the most frequently performed operations in Germany, with approximately 170000 procedures per year. It is therefore essential that physicians should adhere to an appropriate, and patient-centered indication process. The updated guideline indication criteria for knee arthroplasty (EKIT-Knee) contain recommendations, which are based on current evidence and agreed upon by a broad consensus panel. For practical use, the checklist has also been updated.For this guideline update, a systematic literature research was conducted in order to analyse (inter-)national guidelines and systematic reviews focusing on osteoarthritis of the knee and knee arthroplasty, to answer clinically relevant questions on diagnostic, predictors of outcome, risk factors and contraindications.Knee arthroplasty should solely be performed in patients with radiologically proven moderate or severe osteoarthritis of the knee (Kellgren-Lawrence grade 3 or 4), after previous non-surgical treatment for at least three months, in patients with high subjective burden with regard to knee-related complaints and after exclusion of possible contraindications (infection, comorbidities, BMI ≥ 40 kg/m2). Modifiable risk factors (such as smoking, diabetes mellitus, anaemia) should be addressed and optimised in advance. After meeting current guideline indications, a shared decision-making process between patients and surgeons is recommended, in order to maintain high quality surgical management of patients with osteoarthritis of the knee.The update of the S2k-guideline was expanded to include unicondylar knee arthroplasty, the preoperative optimisation of modifiable risk factors was added and the main indication criteria were specified.

Intraoperative Periprostehtic Femur Fracture - When is the Cerclage Enough? / Intraoperative periprothetische Femurfrakturen ­ wann reicht die Cerclage?

BACKGROUND AND PLANNING: Intraoperative periprosthetic femoral fractures are among the most serious complications in both primary and revision arthroplasty. They are often not detected, despite intraoperative radiological control. Since an unnoticed intraoperative fracture often requires revision surgery, which has been associated with increased mortality rates, intraoperative diagnosis and corresponding direct and sufficient treatment are crucial. There are patient-, surgery-, and implant-specific risk factors that increase the possibilities of intraoperative fractures. The most common risk factors on the patient side are age, gender, and various pre-existing conditions, such as osteoporosis or rheumatic diseases. A minimally invasive approach and a cementless press-fit fixation are the most significant surgery- and implant-specific risk factors. The Vancouver classification or the modified Mallory classification are available for the classification of intraoperative periprosthetic femoral fractures. Based on these classifications, treatment recommendations can be derived. Different strategies are available for fracture management. THERAPY: Generally, if the stem is stable, osteosynthesis can be performed with preservation of the implant. This procedure can be applied to the majority of cases with non-displaced fractures by using cerclages as fixation. An unstable implant may require replacement of the stem. In higher grade fractures, stabilisation by using plate osteosynthesis may be necessary. The aim is to achieve the most anatomical reposition possible for the best possible bony consolidation. The ultimate goal is high implant stability and restoration of the biomechanics.

Intraoperative Fractures of the Tibia and Femur in Knee Revision Surgery. / Intraoperative Frakturen von Tibia und Femur in der Revisionssituation.

Intra-operative fractures in knee revision surgery are relatively rare and have not been well studied. They may occur during joint exposition, removal of the prosthesis or cement, or implantation of trial or original components. The fractures affect both the metaphyseal area and diaphysis of the tibia and femur. Tibial fractures are slightly more common than femur fractures. On the femur, the medial condyle is most frequently affected, followed by the femur diaphysis. The use of non-cemented stems is associated with a greater risk of intra-operative diaphyseal fractures than that of cemented stems. Overall, women and patients with an osteopenic bone structure have a higher risk of fractures. It is common that fractures are diagnosed post-operatively. In these cases, conservative therapy may be successful, depending on the stability of the prosthesis and bones. The most common surgical fixation options are cerclages and screws, followed by stem extensions for bridging the fracture. Plate fixation or use of strut grafts are also sensible therapy options. Overall, intraoperative fractures have a high healing potential with stable and good joint function. The revision rate is still 15%, which is most often caused by peri-prosthetic infection.

Transforming growth factor ß1 inhibits bone morphogenic protein (BMP)-2 and BMP-7 signaling via upregulation of Ski-related novel protein N (SnoN): possible mechanism for the failure of BMP therapy?

BACKGROUND: Bone morphogenic proteins (BMPs) play a key role in bone formation. Consequently, it was expected that topical application of recombinant human (rh)BMP-2 and rhBMP-7 would improve the healing of complex fractures. However, up to 36% of fracture patients do not respond to this therapy. There are hints that a systemic increase in transforming growth factor ß1 (TGFß1) interferes with beneficial BMP effects. Therefore, in the present work we investigated the influence of rhTGFß1 on rhBMP signaling in primary human osteoblasts, with the aim of more specifically delineating the underlying regulatory mechanisms. METHODS: BMP signaling was detected by adenoviral Smad-binding-element-reporter assays. Gene expression was determined by reverse transcription polymerase chain reaction (RT-PCR) and confirmed at the protein level by western blot. Histone deacetylase (HDAC) activity was determined using a test kit. Data sets were compared by one-way analysis of variance. RESULTS: Our findings showed that Smad1/5/8-mediated rhBMP-2 and rhBMP-7 signaling is completely blocked by rhTGFß1. We then investigated expression levels of genes involved in BMP signaling and regulation (for example, Smad1/5/8, TGFß receptors type I and II, noggin, sclerostin, BMP and activin receptor membrane bound inhibitor (BAMBI), v-ski sarcoma viral oncogene homolog (Ski), Ski-related novel protein N (SnoN) and Smad ubiquitination regulatory factors (Smurfs)) and confirmed the expression of regulated genes at the protein level. Smad7 and SnoN were significantly induced by rhTGFß1 treatment while expression of Smad1, Smad6, TGFßRII and activin receptor-like kinase 1 (Alk1) was reduced. Elevated SnoN expression was accompanied by increased HDAC activity. Addition of an HDAC inhibitor, namely valproic acid, fully abolished the inhibitory effect of rhTGFß1 on rhBMP-2 and rhBMP-7 signaling. CONCLUSIONS: rhTGFß1 effectively blocks rhBMP signaling in osteoblasts. As possible mechanism, we postulate an induction of SnoN that increases HDAC activity and thereby reduces the expression of factors required for efficient BMP signaling. Thus, inhibition of HDAC activity may support bone healing during rhBMP therapy in patients with elevated TGFß serum levels.

Increased flexion position of the femoral component reduces the flexion gap in total knee arthroplasty.

BACKGROUND: The symmetry and equality of the flexion and extension gap are essential for successful endoprosthetic knee arthroplasty. Cruciate ligament sparing endoprosthetic designs are implanted with a measured resection technique, so that the posterior bone resection corresponds to the posterior condyle thickness. However, this correlation only applies if the sagittal alignment is set at 0°. The aim of the present study was therefore to investigate the extent to which the flexion gap is influenced by a flexed implantation of the femoral component. METHODS: The implant geometry of all available sizes of the knee systems Columbus, e.motion (Aesculap), PFC Sigma (DePuy), Natural Knee II, Innex, Nexgen LPS Flex and Gender (Zimmer), and TC Plus (Smith & Nephew) was recorded. Based on this data, a virtual implantation of the femoral component with a sagittal alignment between 0° and 5° of flexion was simulated. The resulting flexion gaps were calculated depending on the component alignment. The relationships between component alignment (in degrees) and flexion gap (in mm) were documented for every implant. RESULTS: The narrowing of the flexion gap with increasing flexion was more or less linear in the range investigated and was dependent on the system used and the implant size. A narrowing of the flexion gap by 1 mm resulted from 2° (1.9°-2.3°) flexion in the e.motion prosthesis, 1.9° (1.6°-2.4°) in the Columbus, 1.6° (1.5°-1.8°) in the PFC Sigma, 2.0° (1.7°-2.4°) in the Nexgen LPS Flex and Gender, 1.7° (1.6°-1.8°) in the Innex, 2.2° (1.5°-2.6°) in the TC Plus and 2.0° (2.0°-2.1°) in the Natural Knee. CONCLUSIONS: Even a small flexion of the femoral component leads to a reduction of the flexion gap and thus potentially to limited mobility in the measured resection technique. On the other hand, in navigation-assisted implantation, slight flexion of the component can possibly be used to adjust the flexion gap smoothly. LEVEL OF EVIDENCE: II.

How much of the PCL is really preserved during the tibial cut?

PURPOSE: There are two different techniques for retaining the posterior cruciate ligament (PCL) in total knee arthroplasty. The attachment of the PCL can be spared during resection of the tibial plateau, so that a small posterior bone block remains. In contrast to this, many surgeons resect the tibial plateau completely and detach a part of the tibial PCL attachment from the resected material. The objective of this study was to determine how big this part is in an anatomical resection of the tibial plateau with 0° and 7° slope and whether it is gender-dependent. METHODS: Two hundred consecutive patients who had undergone MRI of a knee joint were included. Patients were excluded if they were younger than 18 years or had dysplasia of the knee joint or injuries of the posterior cruciate ligament. The MRIs of 182 knees that fulfilled the inclusion criteria were analysed. For each knee, an anatomical tibial resection with 0° and 7° posterior slope was simulated, and the parts of the tibial PCL attachment that were resected and retained were determined. RESULTS: Given a measured tibial resection with 0° slope, 45 ± 28% of the tibial PCL attachment was removed in the men, compared with 46 ± 30% in the women (n.s.). Given a resection with 7° slope, 69 ± 24% of the tibial PCL attachment was removed in the men and 67 ± 25% in the women. This corresponded to a complete resection in 19 men (20%) and 16 women (24%). CONCLUSIONS: Independently of gender, the anatomical resection of the tibia leads to the removal of a considerable part of the tibial PCL attachment, if this is not spared in the form of a bone block during resection. This becomes increasingly relevant with higher posterior slope of the resection plane. In the case of a cruciate-retaining surgical technique, the retention of the posterior tibial cortical bone in the area of attachment of the PCL is therefore strongly recommended. LEVEL OF EVIDENCE: II.

Graft-dependent differences in the ligamentization process of anterior cruciate ligament grafts in a sheep trial.

PURPOSE: The structural properties of the healing ligament are the determining factor for the stability of the reconstruction before, during, and after osseous integration of anterior cruciate ligament grafts. Over the course of ligamentization, the stability of synovialized grafts seems lower than that of non-synovialized patellar tendon grafts. METHODS: In an animal study on 42 sheep, 21 non-synovialized grafts (patellar tendon) and 21 synovialized grafts (flexor digitorum superficialis tendon) were performed to replace the anterior cruciate ligament. After 6, 12, and 24 weeks, 7 animals from each group were euthanized and investigated. Anteroposterior stability of the knee was assessed. After removal of all other soft tissues, the ACL was loaded to failure. Histology and histological analysis of the intra-articular graft region was then performed. RESULTS: There were no significant differences in the translation test comparing synovialized and non-synovialized grafts. After 6, 12, and 24 weeks, all transplants failed in the tensile test due to interligamentous rupture or avulsion. After 6 weeks, transplants did not show significant biomechanical differences. Load to failure and stiffness of the patellar tendon was more than twice those of synovialized tendon (P = 0.002) after 12 weeks. Histology revealed necrosis in patellar tendon specimens after 12 weeks. A significant increase in load to failure was determined in synovialized ligament grafts between 12 and 24 weeks (P = 0.005). Its load capacity then tended to be higher than that of patellar tendon grafts. CONCLUSION: The stability of synovialized ligament grafts is significantly lower than that of non-synovialized patellar tendon grafts after 12 weeks. This difference is compensated after 24 weeks. The significantly lower load to failure of synovialized compared with non-synovialized grafts after 12 weeks may be clinically relevant for the rehabilitation process of anterior cruciate ligament grafts in humans.

Revision of anterior cruciate ligament reconstruction with patellar tendon allograft and autograft: 2- and 5-year results.

INTRODUCTION: The most common failure reasons of an anterior cruciate ligament (ACL) graft are incorrect positioning of the drill channels and insufficient fixation. In many cases, one-stage revision with patellar tendon graft and the appropriate corrections are possible. For previous use of the ipsilateral patellar tendon third, an allograft seems favorable for reconstruction. So far, no study compared the results of revision surgery of autologous versus allogenous patellar tendon grafts for revision surgery of the ACL in a 5-year follow-up. MATERIALS AND METHODS: A retrospective study was conducted to analyze the clinical outcome and stability results 2 years (19.2 ± 5.8 months) and 5 years (68.8 ± 6.8 months) after revision of ACL reconstruction using middle-third patellar tendon allografts and autografts. The allografts were cleansed by mechanical means only. There were 15 patients in the allograft group and 14 in the autograft group. Patients with isolated re-rupture of the ACL graft were included in the study. Clinical results were evaluated by International Knee Documentation Committee 2000 forms (IKDC), Lysholm score, Tegner activity score, and visual analog scale. Stability was evaluated by means of KT-1000 arthrometer, Lachman test, and pivot-shift test. Location of drill holes was evaluated radiologically. Gonarthritis was graded according to Kellgren and Lawrence on the basis of radiographs. RESULTS: There were no significant differences between the two groups in anterior translation, manual examination for stability, IKDC 2000 findings, Tegner activity score, or Lysholm score. Extension deficits were more frequent in the autograft group at the first follow-up (P = 0.010). Lateral gonarthritis and femoral tunnel widening were more common in the allograft group at the second follow-up (P = 0.049 and P = 0.023, respectively). Pain on walking downhill was significantly more frequent in the allograft group at the second follow-up (P = 0.027). CONCLUSIONS: The functional results with allografts that had not undergone irradiation or chemical sterilization were comparable to those with autografts in ACL revision surgery. Allografts represent a good alternative to autogenous patellar tendons in revision surgery.

Failure Analysis in Multiple TKA Revisions-Periprosthetic Infections Remain Surgeons' Nemesis.

BACKGROUND: The aim of this study was to categorize reasons for failure and to analyze the survivorship of multiple total knee arthroplasty (TKA) revisions. METHODS: The study retrospectively evaluated all multiple TKA revisions performed between 2005 and 2015 at the authors' institutions. Sixty-three patients (35 female, 28 male, age 64 ± 10 years, follow-up 55 ± 36 months) underwent a total of 157 re-revision TKA surgeries (range 2-5). The revision indications were divided up into main diagnoses. Survivorship was evaluated by mixed model analysis. RESULTS: The main overall reason for re-revision was periprosthetic joint infection (PJI) (48%), followed by instability (12%), polyethylene wear (11%), malpositioning (8%), and aseptic loosening (8%). Survivorship shortened with an increasing number of revision surgeries (p = 0.003). While PJI was in 38% of all cases, the reason for the first revision, incidence increased constantly with the number of revisions (48% at second revision, 55% at third revision, 86% at fourth revision, and 100% at fifth revision, p = 0.022). If periprosthetic infection caused the first revision, patients showed an average of two more septic revisions at follow-up than patients with an aseptic first revision indication (p < 0.001). In 36% of cases, the reason for follow-up surgery in case of periprosthetic infection was again PJI. CONCLUSION: The probability of survival of the implanted knee arthroplasty is significantly reduced with each subsequent revision. Periprosthetic infection is the main cause of multiple revisions.

Evaluation of the patient-accompanying app "alley ortho companion" for patients with osteoarthritis of the knee and hip: study protocol for a randomized controlled multi-center trial.

BACKGROUND: Osteoarthritis (OA) is one of the most common disabilities in the elderly. When conservative management fails, total joint arthroplasty (TJA) is the treatment of choice for end-stage OA. Since quality and durability of implants has steadily improved, pre -and postsurgical processes moved into the focus of research. Hence, eHealth approaches offer an opportunity to provide a more available continuity of care. Regarding individualized pre-, peri-, and postsurgical stages, eHealth is expected to improve patient engagement, self-care, and outcomes across the surgical pathway. Aim of this study is to evaluate the effectiveness of the eHealth application "alley" as an adjuvant intervention to TJA. The app provides comprehensive information to empower patient with hip or knee OA to prepare and accompany them for their TJA surgery. Our primary hypothesis is that the pre- and postoperative adjuvant use of the eHealth application "alley" (intervention group, IG) leads to improved functional outcome. METHODS: Prospective, randomized, controlled, multi-center trial including n = 200 patients diagnosed with hip and n = 200 patients with knee OA (n = 200) scheduled for TJA. Patients of both groups will be randomly assigned to one of two study arms. Patients in the intervention group will receive access to the functions of the "alley" app. The app presents informative (e.g., information about osteoarthritis), organizational (e.g., information about medical rehabilitation), and emotional/empowerment (e.g., information about the relationship between mood and pain) content. Patients evaluate their condition and functional level by means of standardized digitally questionnaires. Patients in the control group will not receive any functions of the app. Assessments will be performed at baseline before, 10 days after, 1 months after, 3 months after, 6 months after, and 12 months after TJA. Primary outcome is change from baseline measured by the Hip Osteoarthritis Outcome Score or Knee injury and Osteoarthritis Outcome Score 3 months after TJA. The statistical analysis (t-test for independent variables with effect size Cohen's d) is performed separately for patients with TKA and THA. DISCUSSION: Overall, the study aims to improve the understanding of the benefits of eHealth applications in the treatment of elderly patients with knee or hip arthroplasty. The approach is novel since a health care companion is combined with a digital information platform enabling direct and continuous feedback from the patients to the therapeutic treatment team. As the study investigate the effectiveness under everyday conditions, it is not feasible to control whether the patients in the IG read the educational information of the app respectively the control group consume additional information from other sources. However, this increases the external validity of the study if significant effects for the app can be demonstrated. TRIAL REGISTRATION: German Clinical Trials Register: DRKS00025608. Registered on 21 June 2021.