ACL reconstruction with femoral and tibial adjustable versus fixed-loop suspensory fixation: a retrospective cohort study.

BACKGROUND: Cortical suspensory fixation (CSF) devices gain more and more popularity as a reliable alternative to interference screws for graft fixation in anterior cruciate ligament (ACL) reconstruction. Adjustable-loop fixation may be associated with increased anterior laxity and inferior clinical outcome. The purpose of the study was to compare anterior laxity and clinical outcome after minimally invasive all-inside ACL reconstruction using an adjustable-loop (AL) to a standard technique with a fixed-loop (FL) CSF device. METHODS: Patients who underwent primary single-bundle ACL reconstruction with a quadrupled hamstring autograft at a single institution between 2012 and 2016 were reviewed. In the AL group minimally invasive popliteal tendon harvesting was performed with an all-inside approach (femoral and tibial sockets). In the FL group a traditional anteromedial approach was used for tendon harvesting and a femoral socket and full tibial tunnel were drilled. An objective clinical assessment was performed with Telos x-rays and the International Knee Documentation Committee (IKDC) Objective Score. Patient-reported outcomes (PRO) included the IKDC Subjective Score, the Lysholm Knee Score, the Knee Injury and Osteoarthritis Score (KOOS) and the Tegner Activity Scale. RESULTS: A total of 67 patients were enrolled in this retrospective study with a mean follow-up of 4 (± 1.5) years. The groups were homogenous at baseline regarding age, gender, and the time to surgery. At follow-up, no statistically significant differences were found regarding anterior laxity (AL: 2.3 ± 3 mm vs. FL: 2.3 ± 2.6 mm, p = 0.981). PRO scores were comparable between the AL and FL groups (IKDC score, 84.8 vs. 88.8, p = 0.185; Lysholm 87.3 vs. 89.9, p = 0.380; KOOS 90.7 vs. 91.4, p = 0.720; Tegner 5.5 vs. 6.2, p = 0.085). The rate of saphenous nerve lesions was significantly lower in the AL group with popliteal harvesting of the tendon (8.3% vs. 35.5%, p = 0.014). CONCLUSION: The use of an adjustable-loop device on the femoral and tibial side led to similar stability and clinical results compared to a fixed-loop device.

The Patellar Instability Probability Calculator: A Multivariate-Based Model to Predict the Individual Risk of Recurrent Lateral Patellar Dislocation.

BACKGROUND: Predicting the risk of recurrence is of great interest when counseling patients after primary lateral patellar dislocation (LPD). PURPOSE: To investigate a multivariate model to predict the individual risk of recurrent LPD. STUDY DESIGN: Case-control study; Level of evidence, 3. METHODS: The study population included patients with primary LPD, knee imaging, and a minimum 2-year follow-up after nonoperative treatment. Data including patient characteristics and anatomic patellar instability risk factors were collected retrospectively from 7 national study centers. Bivariate and multivariate regression analyses were carried out to identify risk factors for recurrent LPD and to generate an accuracy-optimized model for out-of-sample prediction. RESULTS: In total, 115 of 201 patients (57%) experienced recurrent LPD within 2 years after primary LPD. Age ≤16 years at primary LPD (odds ratio [OR], 5.0), history of contralateral instability (OR, 2.4), and trochlear dysplasia (Dejour type B-D: OR, 2.5; lateral trochlear inclination ≤12°: OR, 2.7) were significant risk factors for recurrent LPD (P < .05). The prediction accuracy including these 3 risk factors was 79%. Patella alta, an increased tibial tubercle to trochlear groove distance, and patellar tilt had neither an association with increased recurrence rates nor an influence on prediction accuracy of recurrent LPD. CONCLUSION: Young age and trochlear dysplasia are major risk factors for early recurrent LPD. A multivariate model including age at primary LPD, lateral trochlear inclination, and history of contralateral LPD achieved the highest prediction accuracy. Based on these findings, the patellar instability probability calculator is proposed to estimate the individual risk of early recurrence when counseling patients after primary LPD.

Is vertebral body stenting in combination with CaP cement superior to kyphoplasty?

PURPOSE: In the evolution of the minimally invasive treatment of vertebral compression fractures, vertebral body stenting (VBS) was developed to reduce intraoperative and secondary loss of vertebral height. Particularly in combination with the usage of biodegradable cement, the influence of VBS on the rate of intraoperative complications and long-term outcome is unclear. The purpose of this study was to investigate the differences between balloon kyphoplasty (BKP) and VBS regarding their long-term clinical and radiological outcome in combination with calcium phosphate (CaP) application instead of polymethyl methacrylate (PMMA). METHODS: This retrospective study included 49 patients with fresh mono-segmental thoracolumbar fractures without neurological signs treated with VBS or BKP and CaP cement (Calcibone). The outcome was evaluated with the visual analogue pain scale (VAS), the Oswestry disability score (ODI), and radiologically assessed. RESULTS: In the course of the radiological follow-up, the VBS group showed statistically significant less vertebral height loss than the BKP group. However, with respect to VAS and ODI scores there were no statistically significant differences between the VBS and BKP group in the clinical follow-up. The rate of cement leakage was comparable in both groups. CONCLUSIONS: Both techniques facilitated good clinical results in combination with absorbable cement augmentation. In particular, the VBS enabled us to benefit from the advantages of the resorbable isothermic CaP cement with an improved radiological outcome in the long term compared to BKP. However, there was a mentionable loss of reduction in the follow-up in both groups compared to previously published data with PMMA cement. These slides can be retrieved under Electronic Supplementary Material.

Reliability of radiographic landmarks in medial patello-femoral ligament reconstruction in relation to the anatomical femoral torsion.

PURPOSE: Anatomically correct graft positioning at the femoral insertion site is a key factor in surgical reconstruction of the medial patello-femoral ligament (MPFL). Basically there are two techniques to define this point in fluoroscopy during surgery. The role of the anatomical femoral torsion on the accuracy and reproducibility of both procedures has not been clarified. METHODS: Twenty human anatomical leg specimens were dissected. The femoral insertion of the MPFL was marked by two K-wires. The position of the ligament insertion was determined fluoroscopically in the true lateral view as used in routine clinical practice. The anatomical MPFL insertion was compared to the radiographic landmarks which were recommended by two previous studies. The anatomical femoral torsion of the specimens was assessed by computed tomography scans. RESULTS: In true lateral view fluoroscopy, the mean distance of the femoral MPFL insertion was -0.2 mm distal to the vertical reference line intersecting the posterior point of Blumensaat's line. In the anteroposterior direction, the mean distance was -2.0 mm posterior to the femoral cortex reference line. There was no correlation between anatomical femoral torsion and the distance of the femoral MPFL insertion to the posterior cortex. CONCLUSIONS: The results of this study strongly recommend use of a vertical line intersecting the most posterior point of Blumensaat's line as a reference to identify the MPFL insertion in the craniocaudal direction. In the anteroposterior direction, the femoral MPFL insertion showed distinctive variation and was found -2.0 mm posterior to the femoral cortex reference line without being influenced by the anatomical femoral torsion.

Evaluation of fibrin-based gene-activated matrices for BMP2/7 plasmid codelivery in a rat nonunion model.

PURPOSE: Treatment of large-segmental bone defects still is a challenge in clinical routine. Application of gene-activated matrices (GAMs) based on fibrin, bone morphogenic protein (BMP) 2/7 plasmids and nonviral transfection reagents (cationic polymers) could be an innovative treatment strategy to overcome this problem. The aim of this study was to determine the therapeutic efficacy of fibrin GAMs with or without additional transfection reagents for BMP2 and 7 plasmid codelivery in a femur nonunion rat model. METHODS: In this experimental study, a critical-sized femoral defect was created in 27 rats. At four weeks after the surgery, animals were separated into four groups and underwent a second operation. Fibrin clots containing BMP2/7 plasmids with and without cationic polymer were implanted into the femoral defect. Fibrin clots containing recombinant human (rh) BMP2 served as positive and clots without supplement as negative controls. RESULTS: At eight weeks, animals that received GAMs containing the cationic polymer and BMP2/7 plasmids showed decreased bone volume compared with animals treated with GAMs and BMP2/7 only. Application of BMP2/7 plasmids in fibrin GAMs without cationic polymer led to variable results. Animals that received rhBMP2 protein showed increased bone volume, and osseous unions were achieved in two of six animals. CONCLUSIONS: Cationic polymers decrease therapeutic efficiency of fibrin GAM-based BMP2/7 plasmid codelivery in bone regeneration. Nonviral gene transfer of BMP2/7 plasmids needs alternative promoters (e.g. by sonoporation, electroporation) to produce beneficial clinical effects.

The optimal carrier for BMP-2: a comparison of collagen versus fibrin matrix.

INTRODUCTION: The aim of our study was to investigate in vitro and in a new in vivo rat model for impaired bone healing whether a low dose BMP-2 preparation in fibrin would be equivalent or better than the combination of collagen and a high dose of BMP-2 which is currently in clinical use. MATERIALS AND METHODS: In a 14 day period we compared the in vitro release kinetics of an absorbable collagen sponge (ACS) with 72 µg rhBMP-2 in the BMPC group and fibrin matrix with 10 µg rhBMP-2 in the BMPF group. In our in vivo experiment a critical sized osteotomy was performed in the rat femur, which was filled with a spacer, inhibiting bone formation for a period of 4 weeks. In a second operation this spacer was removed and the test item was applied into the defect. We compared the BMPF and BMPC groups with the ACS alone, FIBRIN alone and the EMPTY (4w/8w) control groups. 4 and 8 weeks after the second operation, specimens were analysed by X-ray and µCT imaging. Mechanically stable femurs were biomechanically evaluated. RESULTS: Cumulative BMP-2 release was five times higher in the BMPF group than in the BMPC group during the observation period. µCT analysis revealed that both the extent of bone union and the bone volume were significantly higher in the group with a lower dose of BMP-2 in fibrin matrix than in the groups without BMP-2 treatment. However there was no statistically significant difference between the BMPF and BMPC groups. CONCLUSION: We conclude that fibrin matrix is an excellent carrier for BMP-2 and that it provides equivalent results with a sevenfold lower dose of BMP-2 compared with ACS.

BMP-2 but not VEGF or PDGF in fibrin matrix supports bone healing in a delayed-union rat model.

Treatment of delayed bone healing and non-unions after fractures, osteotomies or arthrodesis still is a relevant clinical challenge. Artificially applied growth factors can increase bone healing and progressively gain importance in clinical routine. The aim of this study was to determine the effects of rhPDGF-BB, rhVEGF-165, and rhBMP-2 in fibrin matrix on bone healing in a delayed-union rat model. Thirty-seven rats underwent a first operation where a standardized femoral critical size defect was created. A silicone spacer was implanted to impair vascularization within the defect. At 4 weeks the spacer was removed in a second operation and rhPDGF-BB, rhVEGF-165, or rhBMP-2 were applied in a fibrin clot. Animals in a fourth group received a fibrin clot without growth factors. At 8 weeks fibrin bound rhBMP-2 treated animals showed a significantly increased union rate and bone volume within the defect compared to the other groups. Single application of fibrin bound rhPDGF-BB and rhVEGF-165 failed to increase bone healing in our atrophic non-union model.