Primary stability of the Activ L® intervertebral disc prosthesis in cadaver bone and comparison of the keel and spike anchoring concept.

BACKGROUND: High primary stability is the key prerequisite for safe osseointegration of cementless intervertebral disc prostheses. The aim of our study was to determine the primary stability of intervertebral disc prostheses with two different anchoring concepts - keel and spike anchoring. METHODS: Ten ActivL intervertebral disc prostheses (5 x keel anchoring, 5 x spike anchoring) implanted in human cadaver lumbar spine specimens were tested in a spine movement simulator. Axial load flexion, extension, left and right bending and axial rotation motions were applied on the lumbar spine specimens through a defined three-dimensional movement program following ISO 2631 and ISO/CD 18192-1.3 standards. Tri-dimensional micromotions of the implants were measured for both anchor types and compared using Student's T-test for significance after calculating 95 % confidence intervals. RESULTS: In the transverse axis, the keel anchoring concept showed statistically significant (p < 0.05) lower mean values of micromotions compared to the spike anchoring concept. The highest micromotion values for both types were observed in the longitudinal axis. In no case the threshold of 200 micrometers was exceeded. CONCLUSIONS: Both fixation systems fulfill the required criteria of primary stability. Independent of the selected anchorage type an immediate postoperative active mobilization doesn't compromise the stability of the prostheses.

Medial patellofemoral ligament reconstruction fails to correct mild patella alta in cases of patellofemoral instability-a case-control study.

PURPOSE: Medial patellofemoral ligament reconstruction (MPFL-R) is the gold standard in patella soft tissue surgery for patellofemoral instability. Although claimed, recent reports indicate that MPFL-R may fail to distalize the patella in mild cases of patella alta. The present study is a retrospective case-control study to compare radiographic patella height between MPFL-R and historical Insall's proximal realignment (IPR) pre- and post-operatively with respect to distalization and assess redislocation rates at a mid-term follow-up. METHODS: Sixty-four patients were age/sex matched (1:1), yielding 32 patients for group 1 MPFL-R (cases) and 32 patients for group 2 IPR (controls). Insall-Salvati, Blackburne-Peel and Caton-Deschamps indices were analyzed for differences pre- and post-operatively. An additional inter-rater reliability analysis was performed by means of intra-class correlation (ICC). Redislocation rates were considered as treatment failures in this study. RESULTS: ICC was excellent for all three patella indices. MPFL-R failed to show significant differences if compared to IPR with respect to distalization in mild stages of patella alta. Moreover, redislocation rates significantly favored MPFL-R (3.1%) over IPR (12.5%; p < 0.0001). CONCLUSIONS: MPFL-R has become a popular option to restore native patellofemoral biomechanics after ligament rupture. However, the procedure's potential to correct concomitant patella alta should not be overestimated and indications considered carefully.

Validation of a German version of the International Hip Outcome Tool (G-iHOT33) according to the COSMIN checklist: how much improvement is clinically relevant?

PURPOSE: The evaluation of the subjective health-related quality of life is especially for young, active patients with hip joint disorders important. The MAHORN study group has recently developed the "International Hip Outcome Tool" (iHOT33), a self-administered patient-reported outcome tool, which includes questions on the patient's symptoms, functional and sports limitations as well as social, emotional, and occupational limitations. The purpose of this study was to adapt and validate a German version of the iHOT33 according to the COSMIN checklist. METHODS: To validate the G-iHOT33, we conducted a prospective multicenter cohort study on patients with hip disorders and a score ≥4 on the modified Tegner Activity Scale. The patients completed the G-iHOT33 questionnaire twice at intervals of at least 2 weeks. In addition, we recorded the Hip Outcome Score (HOS), a modified Tegner Activity Scale (TAS), the EuroQol-5D (EQ5-D), and a subjective assessment of the limitations. Evaluation of psychometric properties was conducted following the COSMIN checklist for validation of health status measurement instruments. The methodical testing for reliability included internal consistency, test-retest reliability, and measurement error. For testing of validity, we analyzed construct validity, hypotheses testing, interpretability, and responsiveness. RESULTS: Between December 2013 and December 2014, eighty-three consecutive patients completed both questionnaires and were available for data analysis. Cronbach's α was 0.97 (95% CI 0.96, 0.99) confirming internal consistency and test-retest reliability of the G-iHOT-33 was high with an ICC = 0.88 (95% CI 0.80, 0.99). All a priori hypotheses were confirmed, further, no floor- or ceiling-effects occurred. The G-iHOT33 showed good responsiveness with a minimal important change (MIC) of 10 points. CONCLUSIONS: The German translation of the iHOT-33 (G-iHOT-33) is a viable tool for the evaluation of active patients with a hip disorder. Following the complete COSMIN checklist, we could prove that G-iHOT33 is a reliable, valid, and responsive PRO measurement tool. We could show that the minimal important change, a change of health condition the patient discerns is 10 points in the G-iHOT33 scale. This is the first study providing results on psychometric properties of the iHOT33 subscales. Level of evidence 1b validating cohort study.

Does osteoporosis reduce the primary tilting stability of cementless acetabular cups?

BACKGROUND: Cementless hip cups need sufficient primary tilting stability to achieve osseointegration. The aim of the study was to assess differences of the primary implant stability in osteoporotic bone and in bone with normal bone density. To assess the influence of different cup designs, two types of threaded and two types of press-fit cups were tested. METHODS: The maximum tilting moment for two different cementless threaded cups and two different cementless press-fit cups was determined in macerated human hip acetabuli with reduced (n=20) and normal bone density (n=20), determined using Q-CT. The tilting moments for each cup were determined five times in the group with reduced bone density and five times in the group with normal bone density, and the respective average values were calculated. RESULTS: The mean maximum extrusion force of the threaded cup Zintra was 5670.5 N (max. tilting moment 141.8 Nm) in bone with normal density and.5748.3 N (max. tilting moment 143.7 Nm) in osteoporotic bone. For the Hofer Imhof (HI) threaded cup it was 7681.5 N (192.0 Nm) in bone with normal density and 6828.9 N (max. tilting moment 170.7 Nm) in the group with osteoporotic bone. The mean maximum extrusion force of the macro-textured press-fit cup Metallsockel CL was 3824.6 N (max. tilting moment 95.6 Nm) in bone with normal and 2246.2 N (max. tilting moment 56.2 Nm) in osteoporotic bone. For the Monoblock it was 1303.8 N (max. tilting moment 32.6 Nm) in normal and 1317 N (max. tilting moment 32.9 Nm) in osteoporotic bone. There was no significance. A reduction of the maximum tilting moment in osteoporotic bone of the ESKA press-fit cup Metallsockel CL was noticed. CONCLUSION: Results on macerated bone specimens showed no statistically significant reduction of the maximum tilting moment in specimens with osteoporotic bone density compared to normal bone, neither for threaded nor for the press-fit cups. With the limitation that the results were obtained using macerated bone, we could not detect any restrictions for the clinical indication of the examined cementless cups in osteoporotic bone.

Does intraoperative application of leukocyte-poor platelet-rich plasma during arthroscopy for knee degeneration affect postoperative pain, function and quality of life? A 12-month randomized controlled double-blind trial.

INTRODUCTION: We aimed to identify the effects of intraoperative applied leukocyte-poor platelet-rich plasma (LP-PRP) during knee arthroscopy for degenerative lesions involving pain, function and quality of life. METHODS: We performed a randomized controlled, double-blind trial (RCT) including 58 patients for arthroscopic knee surgery for cartilage or meniscal degeneration with allocation into the LP-PRP (n = 24) or control group (n = 34). During arthroscopy, LP-PRP was injected intra-articular in the intervention group. At baseline, 6 weeks, 6 months and 12 months pain, function, and life quality were assessed. RESULTS: 91 % of enrolled patients were available for 12 months follow-up. Pain was significantly lower in the LP-PRP group (VAS 0.9. vs. 2.3) at 6 (p = 0.008) but not at 12 months (VAS 1.0 vs. 1.6, p = 0.063). LP-PRP application improved the Lysholm Score at 6 (77.5 vs. 65.6, p = 0.033) and 12 months (83.2 vs.70.0, p = 0.007). Assessment of life quality (SF-36) concerning the physical component summary was significantly higher at 6 weeks (33.9 vs. 25.6, p = 0.001) and 6 months (29.9 vs. 27.1, p = 0.027) in the LP-PRP group but equal at 1 year (31.4 vs. 30.1, p = 0.438). CONCLUSIONS: Intraoperative application of LP-PRP may enhance pain reduction and gain of knee function within 6-12 months compared to arthroscopy alone. LEVEL OF EVIDENCE: II, randomized controlled clinical trial with reduced power. CLINICALTRIALS. GOV IDENTIFIER: NCT02189408.

Biomechanical and functional indicators in male semiprofessional soccer players with increased hip alpha angles vs. amateur soccer players.

BACKGROUND: Femoroacetabular impingement (FAI) is predominant in young male athletes, but not much is known about gait differences in cases of increased hip alpha angles. In our study, the hip alpha angle of Nötzli of soccer players was quantified on the basis of magnetic resonance imaging (MRI) with axial oblique sequences. The aim of the current study was to compare the rearfoot motion and plantar pressure in male semiprofessional soccer players with increased alpha angles to age-matched amateur soccer players. METHODS: In a prospective analysis, male semiprofessional and amateur soccer players had an MRI of the right hip to measure the alpha angle of Nötzli. In a biomechanical laboratory setting, 14 of these participants in each group ran in two shoe conditions. Simultaneously in-shoe pressure distribution, tibial acceleration, and rearfoot motion measurements of the right foot were performed. RESULTS: In the semiprofessional soccer group, the mean value of the alpha angle of group was 55.1 ± 6.58° (range 43.2-76.6°) and 51.6 ± 4.43° (range 41.9-58.8°) in the amateur group. In both shoe conditions, we found a significant difference between the two groups concerning the ground reaction forces, tibial acceleration, rearfoot motion and plantar pressure parameters (P < 0.01, P < 0.05, P = 0.04). Maximum rearfoot motion is about 22% lower in the semiprofessional group compared to the amateur group in both shoe conditions. CONCLUSIONS: This study confirmed that semiprofessional soccer players with increased alpha angles showed differences in gait kinematics compared to the amateur group. These findings support the need for a screening program for competitive soccer players. In cases of a conspicuous gait analysis and symptomatic hip pain, FAI must be ruled out by further diagnostic tests.

The deviation of the mechanical leg axis correlates with an increased hip alpha angle and could be a predictor of femoroacetabular impingement.

PURPOSE: This study was designed to evaluate whether the mechanical axis deviation (MAD) of the leg correlates with an increased hip alpha angle as described by Nötzli, which is associated with femoroacetabular impingement (FAI). METHODS: In a retrospective analysis, standing full-length anteroposterior radiographs were analysed in patients who suffered from symptomatic leg alignment. The study included 85 radiographs of 80 patients with an average age of 43.11 years (range 18-60 years). Five patients underwent a bilateral long-leg X-ray examination. All radiographs were transferred as Digital Imaging and Communications in Medicine data files from the Picture Archiving and Communications System into the OrthoPlanner software version 2.3.2. The radiographs were measured by one orthopaedic surgeon and one independent radiologist. RESULTS: The mean value of the alpha angle of Nötzli was 61.43° (49.07-74.04°). A total of 57 (67%) radiographs showed a varus deviation, 25 (29.5%) had a valgus malalignment and three (3.5%) a straight leg axis. Of 82 radiographs, 40 (48.8%) had a moderate axis deviation with a MAD <15 or > - 15 mm and a mean alpha angle of 57.81°, and 42 (51.2%) with extended axis deviation of a MAD > 15 or < - 15 mm had a mean alpha angle of 62.93°; 40 (95.2%) of these 42 showed an alpha angle > 55°. The alpha angle was significantly increased in extended axis deviation compared to moderate axis deviation (P = 0.001). CONCLUSIONS: This study confirmed that increased alpha angles were found significantly at higher degrees of axis deviation on the full-length radiograph. In cases of a MAD >15 or < - 15 mm and symptomatic coxalgia, diagnostic tests must be pursued for FAI.

Prevalence of femoro-acetabular impingement in international competitive track and field athletes.

PURPOSE: The aim of our study was to analyse the prevalence of femoro-acetabular impingement (FAI) in national elite track and field athletes compared to peers using magnetic resonance imaging (MRI) and clinical examination including impingement tests. METHODS: A total of 44 participants (22 national elite track and field athletes and 22 non-athletes) underwent an MRI for radiological findings associated with FAI, including alpha angle, lateral centre edge angle (CEA), findings of labral and cartilage lesions. The study group was furthermore investigated by the hip outcome score (HOS) and a clinical hip examination including range of motion (ROM) and impingement tests. RESULTS: Concerning the cam impingement, there was a significant difference measured by mean alpha angle between the athlete group (52.2 ± 7.29°) and the control group (48.1 ± 5.45°, P = 0.004). Eleven athletes showed a cam impingement, while two probands of the control group had a pincer impingement and one a mixed form (P = 0.0217). There was no statistically significant difference concerning the CEA upon evaluating pincer impingement. Seven track and field athletes had a positive impingement test, whereof three had an increased alpha angle >55°. No participant of the control group showed pathological results in the impingement test (P = 0.0121). CONCLUSIONS: MRI evidence and clinical examination suggest that cam impingement is more common in elite athletes in comparison to non-athletes. At a professional level, the intense practice of track and field athletics is susceptible for FAI.

Comparative study of the femoroacetabular impingement (FAI) prevalence in male semiprofessional and amateur soccer players.

INTRODUCTION: Femoroacetabular impingement (FAI) represents a novel approach to the mechanical etiology of hip osteoarthritis. The cam-type femoroacetabular impingement deformity occurs frequently in young male athletes. The aim of our study was to evaluate the prevalence of FAI in male semiprofessional soccer players using clinical examination and magnetic resonance imaging (MRI), compared to amateur soccer players. In MRI, the α angle of Nötzli is determined for quantifying FAI. MATERIALS AND METHODS: According to power analysis, a total of 22 asymptomatic semiprofessional soccer players with a median of 23.3 years of age (range 18-30 years) and 22 male amateur soccer players with a median of 22.5 years of age (control group, range 18-29 years) underwent an MRI to measure the hip α angle of Nötzli. The α angle of the kicking legs of the semiprofessional group and the amateur group were analyzed. The study group was moreover evaluated by the Hip Outcome Score (HOS) and a clinical hip examination including range of motion (ROM) and impingement tests. RESULTS: In the semiprofessional group, 19 soccer players had a right kicking leg and 1 soccer player had a left kicking leg. 2 soccer players kicked with two feet. In the semi-professional group, the mean value of the α angle of the kicking leg (57.3 ± 8.2°) was significantly higher than in the amateur group (51.7 ± 4.8°, P = 0.008). In the semi-professional group, 15 (62.5 %) of 24 kicking legs had an increased α angle >55°, while 5 (27.3 %) kicking legs of the amateur group had an α angle >55°. Five semi professional soccer players had findings in clinical examination, whereof 4 had an increased α angle >55°. No participant of the amateur group showed pathological results in the clinical examination (P = 0.0484). Overall, semiprofessional soccer players had a higher proportion of an increased α angle than the amateur group. CONCLUSIONS: Semiprofessional players have a higher prevalence of an increased α angle in the kicking leg than the amateur group at the same age. The kicking leg is predisposed for FAI.

Isolated AL bundle reconstruction of the PCL.

INTRODUCTION: The purpose of this study was to evaluate the clinical and radiologic results after isolated reconstruction of the posterior cruciate ligament (PCL) using the semitendinosus (ST) and gracilis (GR) tendons with the arthroscopic single-bundle technique. METHODS: All patients upon whom we had performed a single-bundle PCL reconstruction between 2002 and 2005 prospectively underwent a standardized follow-up examination after 2 years. Isolated PCL reconstruction was carried out on 41 patients during the observation period. Pre- and postoperative stress radiographs were taken using the Telos stress device in order to evaluate the dorsal translation. Knee joint function and degree of activity were recorded using the Tegner activity score, the subjective International Knee Documentation Committee (IKDC) score, and the overall IKDC score. RESULTS: 33 of 41 patients (80.4%, 17 men, 16 women) completed the study. The posterior tibial translation of -10.1 ± 1.8 mm had an overall average improvement to a postoperative value of -5.0 ± 2.5 mm (p < 0.001). The patients showed a significant improvement in the Tegner activity score from an average 2.8 ± 0.8 points to 5.9 ± 1.2 points (p < 0.001). Evaluation of the subjective IKDC showed a significant improvement from a preoperative score of 41.86 ± 11.49 points to a postoperative score of 69.54 ± 11.39 points (p < 0.001). In total, 24 patients (72.8%) exhibited a normal or nearly normal outcome. CONCLUSION: The abovementioned reconstruction technique can achieve a stable knee function in patients with isolated PCL insufficiency. The isolated single-bundle PCL reconstruction offers an improvement regarding the activity level and stability of the knee joint. LEVEL OF EVIDENCE: Level IV.

Intramedullary nailing as a safe and efficient treatment option for all types of displaced proximal humeral fractures in geriatric patients: A retrospective evaluation of 49 patients treated with the new Targon PH+ nail.

BACKGROUND: Implant specific complications and outcome for the use of proximal humeral nails in different fracture types are not well described. OBJECTIVE: Evaluation of adverse effects and outcome of patients treated with the new Targon PH+ implant for proximal humeral fractures in a geriatric population. METHODS: A consecutive series of patients from a single institution was retrospectively evaluated. Adverse events (AE) were assessed from patients' files and during follow-up examination. Current pain level was evaluated using the Visual Analogue Scale (VAS). The disability score of arm, shoulder and hand (DASH) as well as the Constant-Murley score were assessed. Patient satisfaction was evaluated by questionnaire. RESULTS: Forty-nine patients with a mean age of 72.0 ± 10.0 years were included with a follow-up of 2.2 years. Five patients showed twopart fractures (10%), 24 threepart fractures (50%) and 20 fourpart fractures (40%). Additional shaft fracture occurred in twelve cases (24%). Implant-related AE were recorded in six cases (12%). Pain under strain was moderate with a mean of 27.6 ± 27.1 mm. DASH score showed a mean of 25.9 ± 24.9. Constant score of the affected shoulder was 57 ± 23.8 with a mean difference of 16 points compared to reference shoulder. No significant differences in AE, VAS, DASH or Constant score could be found according to fracture groups. Most patients were satisfied with the surgical outcome (84%). CONCLUSIONS: The Targon PH+ nail demonstrated good functional results and low adverse events in geriatric patients. Additional studies including less experienced centres are required to further evaluate the possible benefits of this implant.

Arthroscopy vs. MRI for a detailed assessment of cartilage disease in osteoarthritis: diagnostic value of MRI in clinical practice.

BACKGROUND: In patients with osteoarthritis, a detailed assessment of degenerative cartilage disease is important to recommend adequate treatment. Using a representative sample of patients, this study investigated whether MRI is reliable for a detailed cartilage assessment in patients with osteoarthritis of the knee. METHODS: In a cross sectional-study as a part of a retrospective case-control study, 36 patients (mean age 53.1 years) with clinically relevant osteoarthritis received standardized MRI (sag. T1-TSE, cor. STIR-TSE, trans. fat-suppressed PD-TSE, sag. fat-suppressed PD-TSE, Siemens Magnetom Avanto syngo MR B 15) on a 1.5 Tesla unit. Within a maximum of three months later, arthroscopic grading of the articular surfaces was performed. MRI grading by two blinded observers was compared to arthroscopic findings. Diagnostic values as well as intra- and inter-observer values were assessed. RESULTS: Inter-observer agreement between readers 1 and 2 was good (kappa = 0.65) within all compartments. Intra-observer agreement comparing MRI grading to arthroscopic grading showed moderate to good values for readers 1 and 2 (kappa = 0.50 and 0.62, respectively), the poorest being within the patellofemoral joint (kappa = 0.32 and 0.52). Sensitivities were relatively low at all grades, particularly for grade 3 cartilage lesions. A tendency to underestimate cartilage disorders on MR images was not noticed. CONCLUSIONS: According to our results, the use of MRI for precise grading of the cartilage in osteoarthritis is limited. Even if the practical benefit of MRI in pretreatment diagnostics is unequivocal, a diagnostic arthroscopy is of outstanding value when a grading of the cartilage is crucial for a definitive decision regarding therapeutic options in patients with osteoarthritis.

Hoffa's fat pad impingement treated arthroscopically: related findings on preoperative MRI in a case series of 62 patients.

INTRODUCTION: The morphology of painful impingement of the infrapatellar fat pad (Hoffa's disease), which is characterized by inflammation, swelling, hypertrophy, fibrosis, and/or calcifications, has been well described. The purpose of this study was to investigate whether corresponding characteristic MRI findings could be assessed in patients with infrapatellar fat pad impingement. MATERIALS AND METHODS: This study includes 62 patients with secondary symptomatic Hoffa's fat pad impingement. In these patients, the fat pad was partially resected until no impingement could be determined at full knee movement. Within a maximum of 3 months before arthroscopic surgery, patients had standardized MR imaging using a 1.5 Tesla unit with the following sequences: sagittal T1-TSE, coronal STIR-TSE, transversal fat-suppressed PD-TSE, and sagittal fat-suppressed PD-TSE (Siemens Magnetom Avanto syngo MR B 15). In this case series, the preoperative MRI appearance of the fat pad was evaluated and compared with a cohort of 255 patients without fat pad impingement but with various knee disorders at arthroscopy as well as the same standardized MRI protocol. RESULTS: In patients with Hoffa's fat pad impingement, morphologic changes such as localized edema of the superior and/or posterior part of the fat pad, a deep fluid-filled infrapatellar bursa, non-visualization of vertical and/or horizontal clefts, fibrosis, and calcifications were noted on MR imaging with remarkable frequency. Besides a significant enlargement of the fat pad, each of these MRI findings was significantly associated with impingement of Hoffa's fat pad (P < 0.05). Besides a moderate kappa score for the detection of intrahoffatic calcifications and vertical clefts, kappa values for each finding showed good inter-observer agreement. Results of logistic regression revealed that edema of Hoffa's fat pad was one of the most important diagnostic MRI criteria for the diagnosis of Hoffa's fat pad impingement. CONCLUSION: MR imaging allows identification of several changes that may be related to a symptomatic impingement of Hoffa's fat pad. In patients who are suspected of having infrapatellar fat pad impingement, such MRI findings should be considered and distinguished from other causes of anterior knee pain.

Titanium acetabular cementless cups combined with highly crosslinked polyethylene liner have very low rates of aseptic loosening.

BACKGROUND: There is a clear tendency towards cementless acetabular components in primary total hip arthroplasty. OBJECTIVE: The aim of this study was to assess the long-term clinical and radiological outcome of titanium cementless acetabular cups when combined with a highly crosslinked polyethylene liner. METHODS: This study is a retrospective follow-up of 67 cups in 64 patients. Clinical outcomes were assessed using the Harris Hip Score. Radiolucent lines, osteolysis and loosening were assessed radiologically. Implant survival was determined using the Kaplan-Meier analysis. RESULTS: The average Harris Hip Score at follow-up was 80.3 ± 14.5. Signs of osteolysis were observed in 7.1% of the radiographs. No aseptic loosening of the cup was reported. Survival of the cup with aseptic loosening as an endpoint was 100%. A comparison with 19 other studies using the same material combination demonstrated very similar results. All manufacturers with available studies have at least one report of 100% survivorship at 10-year follow-up for their titanium cup and highly crosslinked polyethylene acetabular component combination with aseptic loosening as an endpoint. CONCLUSIONS: The data suggests that the rate of aseptic loosening of a titanium cup combined with a highly-crosslinked polyethylene liner at 10-year follow-up could be as low as 0%.

Deficits in subtalar pronation and supination proprioception in subjects with chronic ankle instability.

Deficits in joint position sense (JPS) and force sense (FS) are two functional insufficiencies contributing to chronic ankle instability (CAI). To date, JPS and FS have been only investigated in the sagittal and transverse movement planes but not in the functional movement plane of the pronators and supinators defined by the axis of the subtalar joint (STJ). The purpose of this study was to investigate subtalar JPS as well as pronator and supinator FS in supinated and pronated joint angle in subjects with CAI. Using a force transducer and a goniometer integrated in an apparatus with a movement axis corresponding to Inman's STJ axis, JPS and FS were examined in 20 sport students with CAI and 20 age- and sex-matched controls. Compared to uninjured subjects, CAI leads to reduced pronator (p<0.01) and supinator FS (p<0.01) as well as JPS (p<0.05). A significant main effect for 'angle' was found for JPS (P<0.0001). JPS is affected by a significant 'group'×'angle' interaction (p<0.05) indicating reduced JPS in the 24° supinated angle however not in the 8° pronated angle. The angle-specific JPS deficits indicate that the anatomical STJ axis has to be considered when assessing pronation and supination proprioception in subjects with CAI.

Computer-aided planning with exact implementation into surgical technique in TKA is as accurate as intraoperative navigation.

BACKGROUND: Exact positioning of implants and accuracy of alignment are important parameters to provide an long survivorship of endoprostheses after total knee arthroplasty. It was suggested that an alignment within 3∘ from centerline provides the best long-term survivorship of TKA. Therefore, computer-assisted navigation became more important in TKAs. Another tool to improve the accuracy in TKA is the preoperative planning software. OBJECTIVE: Main goal was to determine if advantages of an intraoperative navigation system during TKA can be reached by an exact implementation of a preoperative computer-aided planning. METHODS: Based on all patients (n= 100) underwent primarily TKA in 2015 and 2016 two groups were declared: (1) conventionally operated TKA without navigation system and (2) operation with an optical navigation system. Data on age, sex, date, operative time, severe complications and preoperative vs. postoperative alignment were collected retrospectively. RESULTS: The two groups do not differ in postoperative alignment and frequency of outliers. Furthermore, there was no difference referring to complications and the length of stay in hospital, but operative time was prolonged in the navigation-assisted group. CONCLUSIONS: It can be stated that conventional surgical techniques in TKA are as accurate as navigated ones if an exact preoperative computer aided planning is implemented during surgery.

Patient-specific instruments' routine use over conventional total knee arthroplasty remains inconclusive: Analysis of 961 cases.

BACKGROUND: An increasing demand for total knee arthroplasty (TKA) has pushed innovations in the industry and created a promising new technique called patient specific instruments (PSI). Early reports had promising results such as reducing operative time, cost, and improved alignment. More recent reports are conflicting. OBJECTIVE: We aimed to evaluate bleeding, operative time, complication rates, and in-hospital stay. METHODS: A monocentric retrospective analysis was performed on a total of 961 patients that met inclusion criteria. Four different TKA Systems, two of which were performed using conventional instrumentation (CI) (n= 768) and two with PSI (n= 193) were trialed under the same conditions by three senior surgeons. Operative time, complications, bleeding, range of motion, and length of stay were analyzed. RESULTS: There was no difference in operative time (p= 0.991) and length of hospital stay (p= 0.371) between PSI and CI approaches. Complication rates were lower in the PSI group. CI patients showed less non-compensated blood loss (p< 0.001) but required more transfusions (5.8% vs. 1.5%, p= 0.014). CONCLUSIONS: There was no difference in duration of surgery, length of stay, and total blood loss when performing TKA with PSI or CI. There were fewer complications in the PSI group. It remains debatable whether these findings justify routine use of PSI in TKA.

Transfusions increase complications and infections after hip and knee arthroplasty: An analysis of 2760 cases.

BACKGROUND: Knee and hip replacement surgery are still the mainstay therapy for osteoarthritis. In spite of the improvement of techniques and implants, anemia is a relatively common complication, with transfusion rates of up to 23% in some centers. OBJECTIVE: The purpose of the study was to determine a correlation of transfusions to complications including infection since this topic is still being debated or even disputed in the literature. METHODS: This is a level III, single center retrospective observational cohort study of 2760 unilateral primary knee and hip replacements. Preoperative assessment, the number of transfusions and the occurrence of complications were collected and the correlations were analyzed using analysis of variance and logistic regression. RESULTS: Fifteen percent of all patients developed at least one complication. Transfusion rate was 9%. Risk factors for receiving a transfusion were female gender, hip replacement, American Society of Anesthesiologists' Score (ASA) > III, history of myocardial infarction, chronic cardiac disease, diabetes mellitus, chronic kidney disease, and length of surgery. The risk factors for developing a complication were: ASA score, presence of chronic renal insufficiency, and transfusion during hospital stay. Transfusion increases the risk of complications and infection rate. Complication rate with transfusion was 34.7% and without transfusion 13.2%. Infection rate without transfusion was 0.4% and with transfusion 2.82%. CONCLUSIONS: The complication rate is higher in transfused patients. The number of complications rises linearly with the number of transfusions. Infection rate is also higher after a transfusion. Efforts should be made to reduce the transfusion rate.

Cartilage Surgery in Overweight Patients: Clinical and MRI Results after the Autologous Matrix-Induced Chondrogenesis Procedure.

Modern orthopaedic surgery provides a variety of techniques for cartilage repair. The Autologous Matrix-Induced Chondrogenesis (AMIC) procedure is a single-step technique with a collagen I/III scaffold for the treatment of full-thickness cartilage lesions. The aim of the study was to analyze the outcome of the AMIC procedure in overweight patients with knee cartilage defects. Overweight patients treated with AMIC surgery were followed up by clinical and MRI examination. 9 patients with a cartilage defect of the knee with a mean lesion size of 2.1 ± 1.2 cm2 and an average body mass index (BMI) of 29.3 were available for the follow-up. The Lysholm Score was significantly improved by the AMIC procedure (38 to 67, p ≤ 0.008). The VAS Score was significantly lower after the procedure (9 to 3, p ≤ 0.018). In the postoperative MOCART Scale, the scaffold reached defect covering of 80%. However, 2 patients had to be revised due to persisting knee pain. The AMIC procedure enhances pain reduction and gain of knee function for cartilage defects of overweight patients. However, in cases of an increased BMI, the patient had to be informed that success rate is reduced despite good defect covering.

Deepening trochleoplasty combined with balanced medial patellofemoral ligament reconstruction for an adequate graft tensioning.

AIM: To evaluate our modified deepening trochleoplasty combined with a balanced medial patellofemoral ligament (MPFL) reconstruction for soft tissue alignement. METHODS: Thirty-three knees with with recurrent patellar dislocations and a trochlear dysplasia in 30 patients (m/f = 12/21, mean age 24 ± 9 years) underwent a combination of a modified deepening trochleoplasty and a balanced MPFL reconstruction for a medial soft tissue alignement. After a mean follow-up period of 29 ± 23 mo, patients' return to sports, possible complications as well as the clinical outcomes using the Kujala, International Knee Documentation Committee (IKDC) and Lysholm scoring were evaluated. Moreover, patients' satisfaction with the general outcome, the cosmetic outcome, the pre- and postoperative pain and a potential avoidance behaviour were assessed with additional standardized questionnaires which also included different visual analog scales. RESULTS: There were no signs of a persistent instability. The Kujala score improved from a mean of 64 ± 16 points to 94 ± 9 points, the Lysholm score improved from a mean of 63 ± 17 to 95 ± 6 points and the IKDC score from 58 ± 11 to 85 ± 12 points, P < 0.0001, respectively. The assessment of pain using a visual analog scale showed a significant pain reduction from a mean of 4.8 ± 2.0 to 1.3 ± 3.4 points (P < 0.0001). Two of 26 cases (92%) who were engaged in regular physical activity before surgery did not return to full sporting activities. One patient felt that his sport was too risky for his knee and reported an ongoing avoidance behaviour. The other patient preferred to wait for surgery of her contralateral knee. Of the eight patients who were not engaged in sporting activities before surgery, three started regular sporting activities after surgery. In 31 of the 33 cases (94%), the patients were very satisfied with the clinical outcome of the surgery. Regarding the cosmetic results, no patients felt impaired in their self-confidence and in their clothing decisions. CONCLUSION: Our technique shows a good clinical outcome in terms of the common scorings as well as in terms of pain, return to sports and patient satisfaction.