Experimental guide wire placement for total shoulder arthroplasty in glenoid models: higher precision for patient-specific aiming guides compared to standard technique without learning curve.

BACKGROUND: Patient-specific aiming devices (PSAD) may improve precision and accuracy of glenoid component positioning in total shoulder arthroplasty, especially in degenerative glenoids. The aim of this study was to compare precision and accuracy of guide wire positioning into different glenoid models using a PSAD versus a standard guide. METHODS: Three experienced shoulder surgeons inserted 2.5 mm K-wires into polyurethane cast glenoid models of type Walch A, B and C (in total 180 models). Every surgeon placed guide wires into 10 glenoids of each type with a standard guide by DePuy Synthes in group (I) and with a PSAD in group (II). Deviation from planned version, inclination and entry point was measured, as well as investigation of a possible learning curve. RESULTS: Maximal deviation in version in B- and C-glenoids in (I) was 20.3° versus 4.8° in (II) (p < 0.001) and in inclination was 20.0° in (I) versus 3.7° in (II) (p < 0.001). For B-glenoid, more than 50% of the guide wires in (I) had a version deviation between 11.9° and 20.3° compared to ≤ 2.2° in (II) (p < 0.001). 50% of B- and C-glenoids in (I) showed a median inclination deviation of 4.6° (0.0°-20.0°; p < 0.001) versus 1.8° (0.0°-4.0°; p < 0.001) in (II). Deviation from the entry point was always less than 5.0 mm when using PSAD compared to a maximum of 7.7 mm with the standard guide and was most pronounced in type C (p < 0.001). CONCLUSION: PSAD enhance precision and accuracy of guide wire placement particularly for deformed B and C type glenoids compared to a standard guide in vitro. There was no learning curve for PSAD. However, findings of this study cannot be directly translated to the clinical reality and require further corroboration.

Patellofemoral cartilage defects are acceptable in patients undergoing high tibial osteotomy for medial osteoarthritis of the knee.

BACKGROUND: Patients suffering cartilage defects of the medial compartment with underlying varus deformity do benefit from high tibial osteotomy (HTO) even in the long term. Nonetheless, kinematic and geometric changes especially in the patellofemoral joint have been described. Purpose of the present study was to evaluate the influence of patellofemoral cartilage defects detected during the diagnostic arthroscopy and their influence on HTO's postoperative outcome. METHODS: Ninety patients with a mean follow-up of 10.08 ± 2.33 years after surgery were included. Patients were divided into four groups according to their cartilage status in the patellofemoral joint (A = no defects, B = isolated lesions of the patella, C = isolated lesions of the trochlea, D = kissing lesions). Functional outcome was evaluated before surgery and about ten years thereafter by relying on the IKDC, Lysholm, and KOOS scores. Radiological parameters were assessed pre- and six weeks postoperatively. RESULTS: In groups A to D, the HTO led to significant patellar distalisation in the sagittal view, with the mean indices remaining at or above the limit to a patella baja. All patients in all groups profited significantly from HTO (higher Lysholm score, lower VAS p < 0.001), patients in group D had the lowest outcome scores. Patella height negatively influenced outcome scores in group C (Blackburne-Peel-Index-VAS p = 0.033) and D (Caton-Deschamps-Index-Tegner p = 0.018), a larger valgus correction was associated with lower outcome scores in group D (Lysholm p = 0.044, KOOSpain 0.028, KOOSQOL p = 0.004). CONCLUSION: Long-term results of HTO for varus medial compartment osteoarthritis remain good to excellent even in the presence of patellofemoral defects. Overcorrection should be avoided. Distal biplanar HTO should be considered for patients presenting trochlear or kissing lesions of the patellofemoral joint. TRIAL REGISTRATION: DRKS00015733 in the German Registry of Clinical Studies.

Clinicopathologic characteristics, metastasis-free survival, and skeletal-related events in 628 patients with skeletal metastases in a tertiary orthopedic and trauma center.

BACKGROUND: Skeletal-related events (SREs) due to bone metastases (BM) significantly impact the morbidity and mortality of cancer patients. The present study sought to investigate clinicopathological characteristics, metastasis-free survival (MFS), and SREs in patients referred to a tertiary orthopedic and trauma center. METHODS: Data were retrieved from electronic health records (n=628). Survival curves were estimated utilizing the Kaplan-Meier method. The Cox regression model was used to determine factors influencing MFS based on estimated hazard ratios (HRs). RESULTS: Breast (55.8%) and lung (18.2%), and lung (32.9%) and prostate (16.8%) cancer were the most common cancer types in our cohort in women and men, respectively. Fifteen percent of patients presented with BM as the first manifestation of tumor disease, 23% had metastasis diagnosis on the same day of primary tumor diagnosis or within 3 months, and 62% developed BM at least 3 months after primary tumor diagnosis. Osteolytic BM were predominant (72.3%) and most commonly affecting the spine (23%). Overall median MFS was 45 months (32 (men) vs. 53 (women) months). MFS was shortest in the lung (median 15 months, 95% CI 8.05-19) and longest in breast cancer (median 82 months, 95% CI 65.29-94). Age (≥ 60 vs. < 60 years) and primary cancer grading of ≥2 vs. 1 revealed prognostic relevance. CONCLUSION: Women with breast or lung cancer, men with lung or prostate cancer, age ≥60 years, male sex, and primary cancer grading ≥2 are associated with increased risk for MBD. Intensified follow-up programs may reduce the risk of SREs and associated morbidity and mortality.

Arthroscopic Bankart repair with an individualized capsular shift restores physiological capsular volume in patients with anterior shoulder instability.

PURPOSE: Capsular volume reduction in the context of anterior arthroscopic shoulder stabilization represents an important but uncontrolled parameter. The aim of this study was to analyse capsular volume reduction by arthroscopic Bankart repair with an individualized capsular shift in patients with and without ligamentous hyperlaxity compared to a control group. METHODS: In the context of a prospective controlled study, intraoperative capsular volume measurements were performed in 32 patients with anterior shoulder instability before and after arthroscopic Bankart repair with an individualized capsular shift. The results were compared to those of a control group of 50 patients without instability. Physiological shoulder joint volumes were calculated and correlated with biometric parameters (sex, age, height, weight and BMI). RESULTS: Patients with anterior shoulder instability showed a mean preinterventional capsular volume of 35.6 ± 10.6 mL, which was found to be significantly reduced to 19.3 ± 5.4 mL following arthroscopic Bankart repair with an individualized capsular shift (relative capsular volume reduction: 45.9 ± 21.9%; P < 0.01). Pre-interventional volumes were significantly greater in hyperlax than in non-hyperlax patients, while post-interventional volumes did not differ significantly. The average shoulder joint volume of the control group was 21.1 ± 7.0 mL, which was significantly correlated with sex, height and weight (P < 0.01). Postinterventional capsular volumes did not significantly differ from those of the controls (n.s.). CONCLUSION: Arthroscopic Bankart repair with an individualized capsular shift enabled the restoration of physiological capsular volume conditions in hyperlax and non-hyperlax patients with anterior shoulder instability. Current findings allow for individual adjustment and intraoperative control of capsular volume reduction to avoid over- or under correction of the shoulder joint volume. Future clinical studies should evaluate, whether individualized approaches to arthroscopic shoulder stabilization are associated with superior clinical outcome.

Low-profile double plating of unstable osteoporotic olecranon fractures: a biomechanical comparative study.

BACKGROUND: In the treatment of unstable olecranon fractures, anatomically preshaped locking plates exhibit superior biomechanical results compared with tension band wiring. However, posterior plating (PP) still is accompanied by high rates of plate removal because of soft-tissue irritation and discomfort. Meanwhile, low-profile plates precontoured for collateral double plating (DP) are available and enable muscular soft-tissue coverage combined with angular-stable fixation. The goal of this study was to biomechanically compare PP with collateral DP for osteosynthesis of unstable osteoporotic fractures. METHODS: A comminuted displaced Mayo type IIB fracture was created in 8 osteoporotic pairs of fresh-frozen human cadaveric elbows. Pair-wise angular stable fixation was performed by either collateral DP or PP. Biomechanical testing was conducted as a pulling force to the triceps tendon in 90° of elbow flexion. Cyclical load changes between 10 and 300 N were applied at 4 Hz for 50,000 cycles. Afterward, the maximum load was raised by 0.02 N/cycle until construct failure, which was defined as displacement > 2 mm. Besides failure cycles and failure loads, modes of failure were analyzed. RESULTS: Following DP, a median endurance of 65,370 cycles (range, 2-83,121 cycles) was recorded, which showed no significant difference compared with PP, with 69,311 cycles (range, 150-81,938 cycles) (P = .263). Failure load showed comparable results as well, with 601 N (range, 300-949 N) after DP and 663 N (range, 300-933 N) after PP (P = .237). All PP constructs and 3 of 8 DP constructs failed by proximal fragment cutout, whereas 5 of 8 DP constructs failed by bony triceps avulsion. CONCLUSION: Angular-stable DP showed comparable biomechanical stability to PP in unstable osteoporotic olecranon fractures under high-cycle loading conditions. Failure due to bony triceps avulsion following DP requires further clinical and biomechanical investigation, for example, on suture augmentation or different screw configurations.

Biodegradable magnesium vs. polylactide pins for radial head fracture stabilization: a biomechanical study.

BACKGROUND: Biodegradable implants have gained increasing importance for the fixation of simple displaced radial head fractures to supersede implant removal and to minimize cartilage destruction. Commonly used polylactide pins still lead to higher rates of secondary loss of reduction compared with metal implants. Alternatively, implants made from a magnesium alloy meanwhile are available in a pin design that hypothetically could perform better than polylactide pins. Because biomechanical data of clinical applications are lacking, the goal of the present study was to biomechanically compare magnesium pins to polylactide pins using a Mason type II radial head fracture model. METHODS: Fourteen pairs of fresh-frozen human cadaver radii with a standardized Mason type II radial head fracture were stabilized either by two 2.0-mm polylactide pins (PPs) or two 2.0-mm magnesium pins (MPs). Biomechanical in vitro testing was conducted as 10 cycles of static loading at 0.1 Hz axially and transversally between 10 and 50 N. Afterward, loosening was tested by dynamic load changes at 4 Hz up to 100,000 cycles. Early fracture displacement was measured after 10,000 cycles. Afterward, maximum loads were raised every 10,000 cycles by 15 N until construct failure, which was defined as fracture displacement ≥2 mm. RESULTS: MP osteosynthesis showed a tendency toward higher primary stability on both axial (MP: 0.19 kN/mm, PP: 0.11 kN/mm; P = .068) and transversal loading (MP: 0.11 kN/mm, PP: 0.10 kN/mm; P = .068). Early fracture displacement was significantly higher following PP osteosynthesis (MP: 0.3 mm, PP: 0.7 mm; P = .030). The superiority of MP was also significant during cyclic loading, represented in a higher failure cycle (MP: 30,684, PP: 5113; P = .009) and in higher failure loads (MP: 95 N, PP: 50 N; P = .024). CONCLUSION: According to our findings, in simple radial head fractures, osteosynthesis with magnesium pins show superior biomechanical properties compared with fractures treated by polylactide pins. Prospective investigations should follow to evaluate clinical outcomes and resorption behavior.

The acromioclavicular ligament shows an early and dynamic healing response following acute traumatic rupture.

PURPOSE: Symptomatic horizontal instability is clinically relevant following acute acromioclavicular joint dislocations. However, the intrinsic healing response is poorly understood. The present study sought to investigate time-dependent healing responses of the human acromioclavicular ligament following acute traumatic rupture. METHODS: Biopsies of the acromioclavicular ligament were obtained from patients undergoing surgical treatment for acute acromioclavicular joint dislocations. Specimens were stratified by time between trauma and surgery: group 1, 0-7 days (n = 5); group 2, 8-14 days (n = 6); and group 3, 15-21 days (n = 4). Time-dependent changes in cellularity, collagen (type 1 and 3) concentration, and histomorphological appearance were evaluated for the rupture and intact zone of the acromioclavicular ligament. RESULTS: Group 1 was characterized by cellular activation and early inflammatory response. The rupture zone exhibited a significantly higher count of CD68-positive cells than the intact zone (15.2 vs 7.4; P ≤ 0.05). Consistently, synovialization of the rupture end was observed. Within the second week, the rupture zone was subject to proliferation showing more fibroblast-like cells than the intact zone (66.8 vs 43.8; P ≤ 0.05) and a peak of collagen type 3 expression (group 1: 2.2 ± 0.38, group 2: 3.2 ± 0.18, group 3: 2.8 ± 0.57; P ≤ 0.05). Signs of consolidation and early remodeling were seen in the third week. CONCLUSIONS: The acromioclavicular ligament exhibits early and dynamic healing responses following acute traumatic rupture. Our histological findings suggest that surgical treatment of acute ACJ dislocations should be performed as early as possible within a timeframe of 1 week after trauma to exploit the utmost biological healing potential. Prospective clinical studies are warranted to investigate whether early surgical treatment of ACJ dislocations translates into clinical benefits.

App-Based Tracking of Self-Reported COVID-19 Symptoms: Analysis of Questionnaire Data.

BACKGROUND: COVID-19 is an infectious disease characterized by various clinical presentations. Knowledge of possible symptoms and their distribution allows for the early identification of infected patients. OBJECTIVE: To determine the distribution pattern of COVID-19 symptoms as well as possible unreported symptoms, we created an app-based self-reporting tool. METHODS: The COVID-19 Symptom Tracker is an app-based daily self-reporting tool. Between April 8 and May 15, 2020, a total of 22,327 individuals installed this app on their mobile device. An initial questionnaire asked for demographic information (age, gender, postal code) and past medical history comprising relevant chronic diseases. The participants were reminded daily to report whether they were experiencing any symptoms and if they had been tested for SARS-CoV-2 infection. Participants who sought health care services were asked additional questions regarding diagnostics and treatment. Participation was open to all adults (≥18 years). The study was completely anonymous. RESULTS: In total, 11,829 (52.98%) participants completed the symptom questionnaire at least once. Of these, 291 (2.46%) participants stated that they had undergone an RT-PCR (reverse transcription-polymerase chain reaction) test for SARS-CoV-2; 65 (0.55%) reported a positive test result and 226 (1.91%) a negative one. The mean number of reported symptoms among untested participants was 0.81 (SD 1.85). Participants with a positive test result had, on average, 5.63 symptoms (SD 2.82). The most significant risk factors were diabetes (odds ratio [OR] 8.95, 95% CI 3.30-22.37) and chronic heart disease (OR 2.85, 95% CI 1.43-5.69). We identified chills, fever, loss of smell, nausea and vomiting, and shortness of breath as the top five strongest predictors for a COVID-19 infection. The odds ratio for loss of smell was 3.13 (95% CI 1.76-5.58). Nausea and vomiting (OR 2.84, 95% CI 1.61-5.00) had been reported as an uncommon symptom previously; however, our data suggest a significant predictive value. CONCLUSIONS: Self-reported symptom tracking helps to identify novel symptoms of COVID-19 and to estimate the predictive value of certain symptoms. This aids in the development of reliable screening tools. Clinical screening with a high pretest probability allows for the rapid identification of infections and the cost-effective use of testing resources. Based on our results, we suggest that loss of smell and taste be considered cardinal symptoms; we also stress that diabetes is a risk factor for a highly symptomatic course of COVID-19 infection.

Fluoroscopic guided tunnel placement during medial patellofemoral ligament reconstruction is not accurate in patients with severe trochlear dysplasia.

PURPOSE: Accurate femoral tunnel placement is of great importance during medial patellofemoral ligament (MPFL) reconstruction. Purpose of the present study was to investigate the influence of trochlear dysplasia on the accuracy of fluoroscopic guided femoral tunnel placement. METHODS: CT-Scans of 30 knees (five with regular shaped trochlea, 10 with a Type A and five each with a Type B, C, or D trochlear dysplasia) were imported into the image analysis platform MeVisLab. A 3D Bone Volume Rendering (VR) and a virtual lateral radiograph was created. The anatomic femoral MPFL insertion was identified on the 3D VR. On virtual lateral radiographs, the MPFL insertion was identified based on landmarks described by Schöttle et al. using three different perspectives: Best possible overlap of the femoral condyles (BC) and a tangent along posterior border of the posterior femoral cortex (pBC); a tangent along the anterior border of the posterior cortex (aBC); and best possible overlap of the distal part of the posterior femoral cortex (BF). Distances between the anatomic attachment and radiographically obtained insertions were measured on the 3D VR and compared according to the type of trochlear dysplasia. RESULTS: Significantly lower accuracy of fluoroscopy guided tunnel placement in MPFL reconstruction was found in knees with Type C and D dysplasia. This effect was observed irrespectively from the radiologic perspective (pBC, aBC, and FC). In the pBC view (highest accuracy), the mean distance from the centre of the anatomic MPFL attachment to the radiographically defined location was 4.3 mm in knees without trochlear dysplasia and increased to 4.8 mm in knees with Type A dysplasia, 3.8 mm in knees with Type B dysplasia, 6.7 mm (p < 0.001) in knees with Type C dysplasia, and 7.3 mm (p < 0.001) in knees with Type D dysplasia. CONCLUSION: Radiographic landmark-based femoral tunnel placement in the pBC view provides highest accuracy in knees with a normal shaped trochlea or low grade trochlear dysplasia. In patients with severe dysplasia, fluoroscopy guided tunnel placement has a low accuracy, exceeding a critical threshold of 5 mm distance to the anatomic MPFL insertion irrespective of the radiographic perspective. In these patients, utilization of anatomic landmarks may be beneficial. LEVEL OF EVIDENCE: IV.

Biomechanical comparison of biodegradable magnesium screws and titanium screws for operative stabilization of displaced capitellar fractures.

BACKGROUND: Displaced fractures of the humeral capitellum are commonly treated operatively and fixed by titanium screws (TSs) either directly or indirectly. In the case of direct transcartilaginous fixation, biodegradable screws with the ability to be countersunk can be favorable regarding implant impingement and cartilage destruction. Hence, the goal of this study was to biomechanically compare headless compression screws made from titanium with a biodegradable equivalent made from a magnesium alloy. METHODS: This biomechanical in vitro study was conducted on 13 pairs of fresh-frozen human cadaveric humeri, in which a standardized Bryan-Morrey type I fracture was fixed using 2 magnesium screws (MSs) or 2 TSs. First, construct stiffness was measured during 10 cycles of static loading between 10 and 50 N. Second, continuous loading was applied at 4 Hz between 10 and 50 N, increasing the maximum load every 10,000 cycles by 25 N until construct failure occurred. This was defined by fragment displacement >3 mm. RESULTS: Comparison of the 2 screw types showed no differences related to construct stiffness (0.50 ± 0.25 kN/mm in MS group and 0.47 ± 0.13 kN/mm in TS group, P = .701), failure cycle (43,944 ± 21,625 and 41,202 ± 16,457, respectively; P = .701), and load to failure (152 ± 53 N and 150 ± 42 N, respectively; P = .915). CONCLUSION: Biomechanical comparison showed that simple capitellar fractures are equally stabilized by headless compression screws made from titanium or a biodegradable magnesium alloy. Therefore, in view of the advantages of biodegradable implants for transcartilaginous fracture stabilization, their clinical application should be considered and evaluated.

A high-profile thread with grit-blasted and acid-etched surface reduces loosening of medial column fusion bolt in instable Charcot foot.

BACKGROUND: Intramedullary fusion bolts (FB) were introduced to stabilize the medial column of the instable Charcot foot (ICF), but complications as bolt loosening or breakage are frequent. We compared the use of a standard FB and a high-profile threaded FB with a grit-blasted surface. We hypothesized that implant related complications occurred less often and osseous consolidation of fusion sites was more distinctive using the latter type of FB. METHODS: Consecutive patients suffering from an ICF were stabilized with a high-profile threaded and surface-modified FB (HTFB) (n=20) or with a standard FB (n=20) which was placed into the first ray. Additional bolts and dorsal low-profile plates were applied in every patient. In a retrospective assessment osseous consolidation of the fusion sites was analyzed at 3 month and quantified by CT scan. At 3 and 12 month longitudinal foot arch collapse and rate of bolt loosening were assessed. RESULTS: Compared to the control group, the HTFB group reached significant higher consolidation after 3 month. No dislocation and a single bolt breakage was observed in the HTFB group after the fourth month, while the control group included 3 patients with bolt dislocation at 3±1 month and 5 patients with bolt breakage at 6±1.8 month. Compared to preoperative values, the improvement of Meary's angle after one-year was significant higher in the HTFB group (23.4°±14) than in controls (11.7°±13). CONCLUSIONS: Modification of bolt design improves the stability of the medial column: A higher rate of osseous consolidation of the medial column leads to lower rate of bolt dislocation/breakage and finally to permanently erected longitudinal foot arch. Initially disappointing results following medial column stabilization with fusion bolts can be rejected by modifications of bolt design and its technical application.

Quantification of patellofemoral cartilage deformation and contact area changes in response to static loading via high-resolution MRI with prospective motion correction.

BACKGROUND: Higher-resolution MRI of the patellofemoral cartilage under loading is hampered by subject motion since knee flexion is required during the scan. PURPOSE: To demonstrate robust quantification of cartilage compression and contact area changes in response to in situ loading by means of MRI with prospective motion correction and regularized image postprocessing. STUDY TYPE: Cohort study. SUBJECTS: Fifteen healthy male subjects. FIELD STRENGTH: 3 T. SEQUENCE: Spoiled 3D gradient-echo sequence augmented with prospective motion correction based on optical tracking. Measurements were performed with three different loads (0/200/400 N). ASSESSMENT: Bone and cartilage segmentation was performed manually and regularized with a deep-learning approach. Average patellar and femoral cartilage thickness and contact area were calculated for the three loading situations. Reproducibility was assessed via repeated measurements in one subject. STATISTICAL TESTS: Comparison of the three loading situations was performed by Wilcoxon signed-rank tests. RESULTS: Regularization using a deep convolutional neural network reduced the variance of the quantified relative load-induced changes of cartilage thickness and contact area compared to purely manual segmentation (average reduction of standard deviation by ∼50%) and repeated measurements performed on the same subject demonstrated high reproducibility of the method. For the three loading situations (0/200/400 N), the patellofemoral cartilage contact area as well as the mean patellar and femoral cartilage thickness were significantly different from each other (P < 0.05). While the patellofemoral cartilage contact area increased under loading (by 14.5/19.0% for loads of 200/400 N), patellar and femoral cartilage thickness exhibited a load-dependent thickness decrease (patella: -4.4/-7.4%, femur: -3.4/-7.1% for loads of 200/400 N). DATA CONCLUSION: MRI with prospective motion correction enables quantitative evaluation of patellofemoral cartilage deformation and contact area changes in response to in situ loading. Regularizing the manual segmentations using a neural network enables robust quantification of the load-induced changes. LEVEL OF EVIDENCE: 2 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019;50:1561-1570.

High tibial osteotomy increases patellofemoral pressure if adverted proximal, while open-wedge HTO with distal biplanar osteotomy discharges the patellofemoral joint: different open-wedge high tibial osteotomies compared to an extra-articular unloading device.

PURPOSE: Valgus high tibial osteotomy (HTO) and a recently introduced extra-articular absorber have been shown to efficiently unload the medial compartment of the knee. However, only little is known about the influence of these treatment modalities on biomechanics of the patellofemoral joint. The purpose of this study was to investigate and compare the impact of different HTO techniques and implantation of an extra-articular absorber on patellofemoral contact forces. METHODS: Fourteen fresh frozen cadaveric knees were tested in a specially designed knee simulator that allowed simulation of isokinetic flexion-extension motions under physiological loading. Mean contact pressure (ACP) and peak contact pressure (PCP) of the patellofemoral joint was measured continuously between 0° and 120° of knee flexion using a pressure sensitive film in the following conditions: native, after biplanar medial open-wedge HTO with 5° and 10° correction angle performing an ascending frontal osteotomy of the tibial tuberosity, and after implantation of an extra-articular absorber system (KineSpring®). Including a second testing cycle with a biplanar medial open-wedge HTO with 5° and 10° correction angle performing descending frontal osteotomy of the tibial tuberosity. Values after each procedure were compared to the corresponding values of the native knee. RESULTS: Biplanar proximal osteotomy leaded to a significant increase of retropatellar compartment area contact pressure compared to the first untreated test cycle (Δ 0.04 ± 0.01 MPa, p = 0.04). Similar results were observed measuring peak contact pressure (Δ 1.41 ± 0.15 MPa, p = 0.03). With greater correction angle 5°, respectively, 10° peak and contact pressure increased accordingly. In contrast, the biplanar distal osteotomy group showed significant decrease of pressure values (p = 0.004). The extracapsular, extra-articular absorber had no significant influence on pressure levels in the patellofemoral joint. CONCLUSION: HTO with a proximal biplanar osteotomy of the tuberositas tibia significantly increased patellofemoral pressure conditions depending on the correction angle. In contrast a distally directed biplanar osteotomy diminished these effects while implantation of an extracapsular, extra-articular absorber had no influence on the patellofemoral compartment at all. Consequently, patients with varus alignment with additional retropatellar chondropathia should be treated with a distally adverted osteotomy to avoid further undesirable pressure elevation in the patellofemoral joint.

Clinical and radiographical ten years long-term outcome of microfracture vs. autologous chondrocyte implantation: a matched-pair analysis.

PURPOSE: To compare the clinical and radiographical long-term outcome of microfracture (MFX) and first-generation periosteum-covered autologous chondrocyte implantation (ACI-P). METHODS: All subjects (n = 86) who had been treated with knee joint ACI-P or microfracture (n = 76) with a post-operative follow-up of at least ten years were selected. Clinical pre- and post-operative outcomes were analyzed by numeric analog scale (NAS) for pain, Lysholm, Tegner, IKDC, and KOOS score. Radiographical evaluation was visualized by magnetic resonance imaging (MRI). Assessment of the regenerate quality was performed by the magnetic resonance observation of cartilage repair tissue (MOCART) and modified knee osteoarthritis scoring system (mKOSS). Relaxation time (RT) of T2 maps enabled a microstructural cartilage analysis. RESULTS: MFX and ACI of 44 patients (24 females, 20 males; mean age 38.9 ± 12.1 years) resulted in a good long-term outcome with low pain scores and significant improved clinical scores. The final Lysholm and functional NAS scores were significantly higher in the MFX group (Lysholm: MFX 82 ± 15 vs. ACI-P 71 ± 18 p = 0.027; NAS function: MFX 8.1 ± 3.5 vs. ACI-P 6.0 ± 2.5; p = 0.003). The MOCART score did not show any qualitative differences. KOSS analysis demonstrated that cartilage repair of small defects resulted in a significant better outcome. T2-relaxation times were without difference between groups at the region of the regenerate tissue. CONCLUSION: This study did not demonstrate coherent statistical differences between both cartilage repair procedures. MFX might be superior in the treatment of small cartilage defects.

Modified Lemaire extra-articular stabilisation of the knee for the treatment of anterolateral instability combined with diffuse pigmented villonodular synovitis: a case report.

BACKGROUND: Diffuse pigmented villonodular synovitis (PVNS) of the knee is a rare proliferative joint disease associated with high recurrence rates following surgical treatment. Intra-articular joint instability in conjunction with PVNS implies complex reconstructive strategies due to the destructive nature of the disease. CASE PRESENTATION: Here, we present the case of a young patient with refractory PVNS and a chronic ipsilateral anterior cruciate ligament (ACL) rupture. Clinically, the patient presented with a grade 3 pivot shift phenomenon, indicating anterolateral rotational instability. Usually, PVNS implies a contraindication for ACL reconstruction due to the degenerative and pro-inflammatory joint microenvironment that is induced and maintained by PVNS. Therefore, we have performed a modified Lemaire extra-articular stabilization resulting in significant clinical improvement and subjective joint stability. In the latest follow-up examination at 12 months, the patient reported subjective joint stability and no swelling. In the clinical examination, the patient showed dynamic joint stability during walking. Additionally, the patient presented with grade 0 in pivot-shifting compared to the contralateral knee. The Lachman test exhibited no increased side-to-side difference and a firm endpoint. CONCLUSIONS: Extra-articular anterolateral stabilisation of the knee in patients having anterolateral knee instability combined with PVNS is a safe and efficient surgical treatment option yielding significant clinical improvement as well as subjective joint stability.

Isolated revision meniscal repair - failure rates, clinical outcome, and patient satisfaction.

BACKGROUND: Failure of isolated primary meniscal repair must be expected in approximately 10-25% of cases. Patients requiring revision surgery may benefit from revision meniscal repair, however, the results of this procedure remain underreported. The purpose of this study was therefore to evaluate the outcome and failure rates of isolated revision meniscal repair in patients with re-tears or failed healing after previous meniscal repair in stable knee joints. METHODS: A chart review was performed to identify all patients undergoing revision meniscal repair between 08/2010 and 02/2016. Only patients without concomitant procedures, without ligamentous insufficiency, and a minimum follow-up of 24 months were included. The records of all patients were reviewed to collect patient demographics, injury patterns of the meniscus, and details about primary and revision surgery. Follow-up evaluation included failure rates, clinical outcome scores (Lysholm Score, KOOS Score), sporting activity (Tegner scale), and patient satisfaction. RESULTS: A total of 12 patients with a mean age of 22 ± 5 years were included. The mean time between primary repair and revision repair was 27 ± 21 months. Reasons for failed primary repairs were traumatic re-tears in 10 patients (83%) and failed healing in two patients (17%). The mean follow-up period after revision meniscal repair was 43 (± 23.4) months. Failure of revision meniscal repair occurred in 3 patients (25%). In two of these patients, successful re-revision repair was performed. At final follow-up, the mean Lysholm Score was 95.2 (± 4.2) with a range of 90-100, representing a good to excellent result in all patients. The final assessment of the KOOS subscores also showed good to excellent results. The mean Tegner scale was 6.8 ± 1.8, indicating a relatively high level of sports participation. Ten patients (83%) were either satisfied or very satisfied with the outcome. CONCLUSION: In patients with re-tears or failed healing after previous isolated meniscal repair, revision meniscal repair results in good to excellent knee function, high level of sports participation, and high patient satisfaction. The failure rate is slightly higher compared to isolated primary meniscal repair, but still acceptable. Therefore, revision meniscal repair is worthwhile in selected cases in order to save as much meniscal tissue as possible.

Focal metallic inlay resurfacing prosthesis for the treatment of localized cartilage defects of the femoral condyles: a systematic review of clinical studies.

PURPOSE: To systematically review the results of focal metallic inlay resurfacing prosthesis for the treatment of isolated cartilage defects of the femoral condyles. METHODS: A systematic electronic search of the PubMed database and the Cochrane Library was performed in April 2017 to identify studies that reported clinical or radiographic outcome of focal metallic inlay resurfacing prosthesis for the treatment of isolated cartilage defects of the femoral condyles. Included studies were abstracted regarding study characteristics, patient demographics, prosthetic device and location, indications and contraindications, and outcome measures. Outcome of interest included functional outcome scores, radiographic measures, complications, re-operations, and conversion to arthroplasty. The methodologic quality of the included studies was assessed with the Coleman Methodology Score. RESULTS: Six studies with a total of 186 patients met the inclusion criteria. Five studies were level IV evidence, and one was level III. The methodologic quality of the included studies was good, with a mean Coleman Methodology Score of 78. Two different implants were used: the HemiCAP® (five studies; 66% of study group) and UniCAP® (one study; 34%) implant. The mean age was 46-54 years, and the mean follow-up was 24 months to 7 years. Pre- and post-operative outcome scores were compared in all six studies, and five studies reported significant improvements at the final follow-up for all scores (objective und functional KSS, KOOS, WOMAC, Tegner, HSS Knee and Function score, SF-36 and SF-12 physical component score) except for the SF-36 and SF-12 mental component score. Progression of osteoarthritis was analysed using the Kellgren-Lawrence grading in three studies (30% of study group), with two studies reporting significant progression. The OARSI grading system was analysed in one study with no significant progression. The overall conversion rate to arthroplasty was 22% with considerable differences between the two implants: 9% for HemiCAP® and 47% for UniCAP®. CONCLUSIONS: Focal metallic inlay resurfacing prosthesis seems to be a viable option for a carefully selected group of patients. Significant improvement in knee function and pain was observed in most patients. Uncertainty remains with regard to progression of osteoarthritis because of conflicting results and inconsistent reporting. One out of five patients has to be converted to arthroplasty after an average of 4 years. However, compared to the UniCAP® implant, considerable lower conversion rates were reported for the smaller HemiCAP® implant. LEVEL OF EVIDENCE: Systematic review of level III and IV studies, Level IV.

Arthroscopic patellar release allows timely return to performance in professional and amateur athletes with chronic patellar tendinopathy.

PURPOSE: Return to sports rates in amateur and professional athletes with chronic patellar tendinopathy following arthroscopic patellar release are unpredictable. The present study aims to analyse the effectiveness of arthroscopic patellar release in professional compared to amateur athletes. METHODS: A total of 34 amateur and 20 professional athletes with chronic patellar tendinopathy, refractory to conservative treatment, were studied prospectively and underwent arthroscopic tendon release at the inferior patellar pole. Impact of grouped sports on clinical and functional outcome, subjective patient satisfaction and return to sports rates were assessed. Additionally, preoperative MRI-scans of the knee were evaluated and correlated with clinical outcome. RESULTS: In 40 patients (74.1%) arthroscopic patellar release resulted in complete recovery and return to preinjury exercise levels. Full return to sports was achieved after a median of 3.0 (range 0.5-12.0) months. Functional outcome measures VISA-P (Victorian Institute of sport assessment for patella) and modified Blazina scores improved significantly from pre- to postoperatively (VISA-P: 48.8 vs. 94.0 pts., respectively, p < 0.0001; Blazina: 4.47 vs. 0.5, respectively, p < 0.0001). CONCLUSION: As rapid recovery and timely return to sports are crucial for professional athletes, arthroscopic patellar release should be considered after failed conservative treatment. LEVEL OF EVIDENCE: IV.

Sport-specific outcomes after isolated meniscal repair: a systematic review.

PURPOSE: The purpose of this systematic review was to assess sport-specific outcomes after repair of isolated meniscal tears. METHODS: A systematic electronic search of the MEDLINE and Cochrane database was performed in May 2016 to identify studies that reported sport-specific outcomes after isolated meniscal repair. Included studies were abstracted regarding study characteristics, patient demographics, surgical technique, rehabilitation, and outcome measures. The methodological quality of the included studies was assessed with the Coleman Methodology Score (CMS). RESULTS: Twenty-eight studies with a total of 664 patients met the inclusion criteria. The methodological quality of the included studies was moderate, with a mean CMS of 69.7 ± 8.3. The mean patient age was 26 ± 7.2 years and 71% of patients were male. Mean preoperative Tegner score improved from 3.5 ± 0.3 to 6.2 ± 0.8 postoperatively. Comparing preinjury and postoperative Tegner scores, comparable values were observed (6.3 ± 1.1 and 5.7 ± 0.8, respectively). Return to sports on the preinjury level was achieved in 89%. Mixed-level populations returned to their preinjury activity level in 90% and professional athletes in 86%. Mean delay of return to sports varied between 4.3 and 6.5 months, with comparable results between professional and mixed-level athletes. The pooled failure rate was 21%. The failure rate was lower in professional athletes compared to mixed-level athletes (9% vs. 22%). CONCLUSION: This systematic review suggests that isolated repair of meniscal tears results in good to excellent sport-specific outcomes and a high return to sports rate in both recreational and professional athletes. The failure rate is comparable to systematic reviews not focusing on sportive patients. LEVEL OF EVIDENCE: Level IV systematic review of Level I to Level IV studies.

Customized post-operative alignment improves clinical outcome following medial open-wedge osteotomy.

PURPOSE: High tibial osteotomy (HTO) has gained more importance in the treatment of cartilage damage or osteoarthritis of the medial compartment with concurrent varus deformity. Concerning the extent of axis correction, various different views exist. The aim of this study was to evaluate the effect of the size of axis correction on functional outcome in patients undergoing a valgus HTO. METHODS: From 2005 to 2013, 156 patients with an underlying varus deformity and cartilage damages or unicompartimental osteoarthritis of the medial compartment were treated by HTO. Retrospectively patients were allocated into three different groups according to the degree of axis correction. For this purpose, three adjacent areas, respectively, comprising 5% of the tibial plateau were defined. Limits of those areas were set as follows: with the medial border representing the 0% point and the lateral border representing the 100 point, the three areas were separated according to their limiting intersection points (group A 50-55%, group B 55-60%, group C > 60%). For comparison of the functional outcomes, standardized measures and scores were used (pre-OP: VAS, Lysholm; post-OP: VAS, Lysholm, KOOS). Analysis of the pre- and post-operatively recorded X-rays was effected by means of a planning software (mediCAD, Hectec GmbH, Germany), and statistical analysis was carried out using SPSS Statistics 21.0 (IBM Corp., Armonk, USA). A p value of 0.05 was considered statistically significant. RESULTS: Thirty-nine patients were allocated to group A, 50 patients to group B and 67 to group C. Pre-operatively, patients in each group were of a homogenous constitution. In the groups A-C, HTO proved to reduce the VAS score and to increase the Lysholm score (p < 0.001). Regarding outcome parameters, group A showed significantly better results in terms of increased Lysholm (p = 0.049) and KOOS pain score (p = 0.043). In patients treated by HTO and ACI implantation for medial compartment lesions, the best results were achieved in group A which was of statistical significance in comparison of the Lysholm (p = 0.006) and VAS score (p = 0.045) of groups A and C. In this subgroup, the size of the post-operative valgus angle significantly correlated with the final VAS score (PC 0.364; p = 0.013), final Lysholm score (PC - 0.390; p = 0.007) and KOOS4 (PC - 0.356; p = 0.014). CONCLUSION: HTO for varus deformity in patients with concomitant cartilage damage or osteoarthritis of the medial compartment is a reliable treatment option with satisfying functional outcome. Precise pre-operative planning regarding individual factors in each patient is mandatory; a pathology-based extent of correction leads to a favourable clinical outcome and to a significant reduction in pain. LEVEL OF EVIDENCE: Retrospective cohort study, Level III.