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Hip fractures in the elderly are associated with an increased mortality rate, even if they are operated within the recommended time window. However, the causes of mortality vary considerably depending on the postoperative period and the patients' comorbidities. In the 30-day postoperative period, the most common causes of death are acute processes such as bacterial and aspiration pneumonia followed by myocardial infarction, cancer, gastrointestinal hemorrhage, stroke, pulmonary embolism, and acute renal failure. In the 6-month and 1-year postoperative period, chronic processes appear to be the most important causes of death, as well as decompensation of patients' chronic diseases. To enhance the literature, we performed this literature review to summarize and discuss the causes of mortality of elderly hip fracture patients depending on the postoperative period that they occur, and possibly to address the question what do hip fracture patients die from? Our aim was to perform an interesting and concise paper that the curious reader will find interesting and informative.

Infection after anterior cruciate ligament reconstruction is a rare but devastating complication resulting in a deleterious impact on knee function as well as an increased related cost for treatment and rehabilitation for the patients. There are conflicting reports regarding the rate of infection between bone patellar tendon bone (BPTB) and hamstrings tendon (HT) autografts for anterior cruciate ligament reconstruction. Therefore, we performed this review to summarize all the available data regarding the risk of infection after ACL reconstruction, to provide insight on the infection risk between BPTB and HT autografts, and to discuss current recommendations for the diagnosis and treatment of these infections. The incidence and risk of infection after ACL reconstruction with HT graft is higher compared with BPTB grafts. The most commonly subacute and late infections, quadruple type, need for cannulated instruments for harvesting, size and shape and fixation of the extra-tunnel material of the HT are important risk factors for infection. Combined antibiotics administration and adequate arthroscopic lavage and debridement are the optimal treatments for ACL reconstruction infection. Early diagnosis and treatment is the most important predictor for graft retention, which accounts more commonly for BPTB grafts. The treating physicians should be aware of the higher incidence of infection after ACL reconstruction with HT graft, as well as for the need for a high clinical suspicion for early diagnosis of the infection. These will increase the possibility of eradication of the infection and retention of the graft.

Developmental dysplasia of the hip (DDH) is the most common musculoskeletal disorder of the infant age. Its incidence ranges from 0.06/1000 to 76.1/1000 live births and is more frequent in female infants. Breech position, family history and firstborn children are the main risk factors for DDH and this disorder is also associated with the presence of other congenital deformities. Anatomically, the acetabulum remains shallow and the femoral head grows in a wrong position. Clinical examination is important and tests such us Barlow and Ortolani give indications only for a part of the spectrum of this entity. Nowadays the sonographic examination is the most accurate option for the diagnosis. Graf classification categorizes the DDH cases in four types, from normal to dislocated hip, by description and measuring specific angles in sonographic examination. The wide usage of ultrasonography has decreased the non-diagnosed or neglected cases; treatment begins immediately in young age and is usually conservative with the usage of devices such as Pavlik harness and hip spica. To enhance the literature, we searched for published studies on DDH, to summarize the pathogenesis and the diagnosis and to discuss the treatment and outcome of the patients with this disorder.

Ultrasound imaging of peripheral nerves is challenging in elderly population. In cases involving the lumbar plexus (LP), we have employed ultrasound imaging and neurostimulation guidance for successful localization and block of the LP. The postero-medial segment of the psoas muscle (PSM), superior to the vertebral body and anterior to the transverse process ("corner pocket") was used as an imaging landmark for the implementation of the LP block. By advancing the needle through the lateral abdominal wall into the "corner pocket" we were afforded a seamless advancement of the needle into the postero-medial segment of the PSM, which is the standard anatomic position of LP in the PSM. Forty-eight patients in whom ultrasound imaging of the LP was not feasible, but the "corner pocket" was clearly depicted were included in the study. LP block characteristics and adverse events were recorded. The LP was localized in 43/48 patients. The average imaging, needling, and performance times to complete the block were 51 sec (range, 6-180 sec), 81 sec (range, 16-236 sec), and 132 sec (range, 24-270 sec), respectively. The median number of needle redirections per patient was 5.5 (range, 1-13). The local anesthetic spread was visualized in the postero-medial segment of the PSM in 39/43 patients. No complications were recorded. The imaging, needling, and performance times, as well as the number of needle passes did not significantly differ between obese and non-obese patients. In conclusion, in cases with challenging ultrasound imaging of the LP, ultrasound-assisted LP block can be accomplished through the lateral abdominal wall by using as an imaging landmark the "corner pocket" at the postero-medial quadrant of the PSM.

Medulloscopy refers to the visualization of the intramedullary canal with an arthroscope, providing access to the infection site without the need for an extensive approach therefore not compromising the surrounding soft tissue. It provides information regarding the extent of the infected endosteal surface of bone, and it allows a thorough debridement of the intramedullary canal in a controlled manner. Therefore, it can be used as an adjunct to traditional open surgical techniques, to perhaps help to visualize hard to see intramedullary areas. This article reports a patient with chronic osteomyelitis of the distal metaphysis of the femur that was treated successfully with intramedullary debridement through medulloscopy. The sinus tract reaching down to the femoral bone and communicating with the intramedullary canal was excised, and a cortical window was formed through which the arthroscope was inserted and thorough irrigation of the intramedullary canal and excision of necrotic and infected bone was done. A second medulloscopy through the same approach was necessary 3 months later because of persistent infection. At 3-year follow-up, the patient was well without any clinical or radiographic evidence of recurrent infection. Medulloscopy can be very useful in localized osteomyelitis as an adjunct to traditional surgical techniques; it helps to visualize hard to see intramedullary areas and adequately addresses the infection, while the damage to surrounding soft-tissue is limited.

Echinococcosis or hydatid disease affecting the spine is an uncommon manifestation of Echinococcus granulosus infection of the spine. More commonly found in endemic areas, it causes significant morbidity and mortality as it grows slowly and produces symptoms mainly by compressing the spinal cord. As diagnostic methods are non-specific, diagnosis and management are usually delayed until the disease is advanced, thereby therapy is usually unlikely. Treatment is usually surgical, aiming at cyst excision, spinal cord decompression and spinal stabilization. This article summarizes the clinical findings of echinococcosis of the spine, discusses the specific laboratory and diagnostic findings, lists the current treatment options, and reviews the patients’ outcomes. The aim is to prompt clinicians to be aware of the possibility of echinococcosis as a possible diagnosis in endemic areas. Cite this article: EFORT Open Rev 2021;6:288-296. DOI: 10.1302/2058-5241.6.200130

Engineering complex tissues is perhaps the most ambitious goal of all tissue engineers. Despite significant advances in tissue engineering, which have resulted in successful engineering of simple tissues such as skin and cartilage, there are a number of challenges that remain in engineering of complex, hybrid tissue structures, such as osteochondral tissue. Mesenchymal stem cells (MSCs) have the capacity to highly proliferate in an undifferentiated state and the potential to differentiate into a variety of different lineages, providing a promising single cell source to produce multiple cell types. MSC obtained from adult human contribute to the regeneration of mesenchymal tissues such as bone, cartilage, fat, muscle, tendon and marrow stroma. In the present study, the regeneration capacity of multipotent MSCs derived from different tissues in the rabbit were compared. Specifically the aim of this study was to isolate and characterize rabbit adult stem cell populations from bone marrow, adipose, synovial membrane, rotator cuff, ligament and tendon and assess their cell morphology, growth rate, cell surface markers and differentiation capacity. MSCs derived from synovial membrane showed superiority in terms of chondrogenesis, osteogenesis, myogenesis and tenogenesis, suggesting that synovial membrane-derived MSCs would be a good candidate for efforts to regenerate musculoskeletal tissues.

Lateralized tibial tubercle is a cause of patellar instability. Before proceeding with reduction of the tibial tubercle-trochlear groove (TT-TG) distance, surgeons prefer to know whether this distance is pathologic. However, the pathological value remains discussed and may vary with the size of the knee. We sought to determine variability in the traditional TT-TG distance versus the anthropometric knee size, using dimensions of the distal part of the femur and proximal part of the tibia of 85 CT scans of the knees in two groups of knees, one normal group without history of patellofemoral instability and one pathologic group with history of instability. The average TT-TG distance measured 13 mm in normal knees and 16.4 mm in pathologic knees. The variability in measurements between normal and pathologic knees varied respectively between ± 5 and ± 15 mm, with as consequence absence of threshold value between normal and pathologic knees. These measurements were supplemented by an analysis of a size ratio coefficient. In the normal group without history of instability, linear regression analysis showed that patients with larger knees tended to have higher TT-TG distances and that the values are associated with the mean ML femoro-tibial width (p = 0.014; Pearson coefficient = 0.4). The knees with history of instability also keep proportional increase of TT-TG with the size of the knee as the knees without history of instability. We developed a nomogram to more appropriately represent the normal values for a given size of the knee. Application of the nomographic model on the CT scan TT-TG data of the patients who have knee instability allows the orthopaedic surgeon to associate the TT-TG distance with the knee size and to evaluate the medial transfer corresponding to the knee size. The average TT-TG distances in normal and pathologic knees were not identical for each size of the knees.

Case: Surgical management of tibial plateau fractures can be challenging, and complications can be devastating. We report the case of a lateral tibial plateau fracture malunion with an associated intra-articular depression, which we treated with an open-book osteotomy, obviating the need for an early corrective osteotomy or knee arthroplasty. Conclusion: A tibial plateau fracture malunion can be reconstructed. The surgical team should give priority to salvage options, which can obviate or delay the need for and the implications of an early total knee arthroplasty, especially in a young and active patient.

An illustrated case with Morton’s metatarsalgia is presented. MR imaging was helpful for determining the presence, location and magnitude of intermetatarsal neuroma. Moreover, it had a large influence on the differential diagnostic thinking because many disorders may produce forefoot complaints mimicking Morton’s metatarsalgia.

Lower-extremity angular deformities are among the most common non-traumatic conditions in children being referred to pediatric orthopedists. Understanding of this abnormality and knowledge of current treatment is essential for pediatricians and primary caregivers. A development in the surgical management of these problems has improved the quality of care of affected children and adolescents. Traditionally, angular deformities are treated by means of osteotomy. In patients who are skeletally immature, this major intervention can be avoided by influencing or guiding the growth of the affected physis using hemiepiphysiodesis techniques. Recently, alternative surgical techniques and implants have been described for improved control of the guided growth.

Educational Objectives 1. Identify the available types of computer-assisted navigation in orthopedic surgery. 2. Summarize the clinical applications of computer-assisted navigation in orthopedic surgery. 3. Review the results of related series using computer-assisted navigation in orthopedic surgery. 4. Recognize the disadvantages and pitfalls of computer-assisted navigation in orthopedic surgery. Computer-assisted navigation has a role in some orthopedic procedures. It allows the surgeons to obtain real-time feedback and offers the potential to decrease intra-operative errors and optimize the surgical result. Computer-assisted navigation systems can be active or passive. Active navigation systems can either perform surgical tasks or prohibit the surgeon from moving past a predefined zone. Passive navigation systems provide intraoperative information, which is displayed on a monitor, but the surgeon is free to make any decisions he or she deems necessary. This article reviews the available types of computer-assisted navigation, summarizes the clinical applications and reviews the results of related series using navigation, and informs surgeons of the disadvantages and pitfalls of computer-assisted navigation in orthopedic surgery.

Although computer-assisted navigation has been used in clinical practice for more than 15 years, it has only recently started to gain acceptance in a variety of orthopedic procedures. Different types of computer-assisted navigation are available, which allow the surgeon to obtain real-time feedback and offer him the potential to decrease intraoperative errors. However, its increased cost and lacking evidence of long-term superiority have made many surgeons skeptical about its clinical usefulness. The scope of this article is to review the clinical applications of computer-assisted navigation in orthopedic surgery of the knee joint.

The accuracy and efficiency of automated cutting guides in CAS systems have not been previously compared with conventional CAS techniques. Therefore, it is not yet clear if these more advanced technologies are warranted. We hypothesized that a novel automated cutting guide with CAS for total knee arthroplasty would be more efficient and more accurate than conventional navigation with sequential cutting blocks. Twelve cadaver legs were used in total. Each leg was randomly assigned to either an automated guide positioning or a conventional freehand computer-navigated guide positioning. The guide positions postosseous fixation and the final bone-cut surfaces were digitized and compared to the targeted cutting planes. The final location of the impacted trial implant was also digitized and compared to the planned implant location. The time for each step and the total time taken to prepare the femur were measured for both groups. The mean femoral preparation time was shorter with the automated cutting guide than the conventional method (5.5 min versus 13.8 min, p0.001). The average deviation in the final bone resections from the planned resections was significantly lower for the automated cutting guide in the frontal/rotational plane (0.55° versus 1.1°), sagittal plane (0.75° versus 2.0°), and cut height direction (0.56 mm versus 1.6 mm). Therefore, based on these results, we concluded that automated cutting-guide positioning resulted in more efficient and more accurate femoral cuts in comparison to the conventional navigation method in a cadaveric model.

Background: We evaluated the anatomic basis and the clinical results of an ultrasound-guided saphenous nerve block close to the level of the nerve9s exit from the inferior foramina of the adductor canal. Methods: The anatomic study was conducted in 11 knees of formalin-preserved cadavers in which the saphenous nerve was dissected from near its exit from the inferior foramina of the adductor canal. The clinical study was conducted in 23 volunteers. Using a linear probe, the femoral vessels and the sartorius muscle were depicted in short-axis view at the level where the saphenous nerve exits the inferior foramina of the adductor canal. Ten milliliters of 1.5% lidocaine was injected into the compartment structured by the sartorius muscle and the femoral artery. Results: The saphenous nerve was found to exit the adductor canal from its inferior foramina in 9 (81.8%) of 11 and at a more proximal level in 2 (18.2%) of 11 of the anatomic specimens. In a single specimen (9%), the saphenous nerve was formed by the anastomosis of 2 branches. In all the dissections, the saphenous nerve, after exiting the adductor canal, passed between the sartorius muscle and the femoral artery. Of the 23 volunteers, 22 responded with a complete sensory block, whereas a single volunteer demonstrated no sensory blockade. None of the volunteers experienced a motor block of the hip flexors and knee extensors. Conclusions: Ultrasound-guided injection directly caudally from the inferior foramina of the adductor canal, between the sartorius muscle and the femoral artery, seems to be an effective approach for saphenous nerve block.

Anchor placement on the glenoid rim is challenging with the angle of insertion critical to achieving satisfactory results. Incorrect anchor placement is a common problem.Three plastic shoulder models were used. Reference markers were attached in the posterior portion of the acromion. Using the navigation system, reference point data from the glenoid were acquired. An anterior labral lesion of the glenoid was created that extended from the 1 o'clock to the 5 o'clock position. Three suture anchors were placed under arthroscopic guidance without the aid of navigation system (Group A) and with the aid of navigation system (Group B). Deviation from the optimal angle of 45° for anchor placement was measured and compared between the two groups.The mean insertion angles for anchor placement were 45.9° (SD 3.4°, 40.2°-50.4°) and 41.4° (SD 3.9°, 33.1°-47.6°) in the freehand (Group A) and navigated (Group B) groups, respectively. There was a statistically significant difference between the groups (P 0.05). The mean deviation (from the optimal angle) was 4.2° (SD 3.2°, 0.0°-11.9°) and 2.8° (SD 2.2°, 0.2°-8.4°) in the freehand and navigated groups, respectively.Navigation systems may improve the accuracy of glenoid anchor placement amongst low-volume shoulder surgeons. However, it does not provide any significant advantage over the freehand technique in a plastic shoulder model. Constant multiplanar visualization throughout anchor placement as facilitated by navigation made the procedure more manageable, even for an experienced surgeon.

Computer-navigation in total knee arthroplasty has been reported to increase accuracy but also procedure duration. We compared surgical time and precision using a novel adjustable cutting block vs freehand navigation with conventional blocks on 12 bilateral cadaver tibiae. The mean time required was significantly less to position the adjustable block than the conventional block (2 minutes 10 seconds vs 6 minutes 35 seconds, P = .006). Guide positioning precision (standard deviation) for the adjustable block vs conventional block was as follows: varus/valgus, 0.24 degrees vs 1.16 degrees (P = .015); posterior slope, 0.35 degrees vs 0.74 degrees (P = .13); and cut height, 0.37 vs 1.41 mm (P = .010). There were no significant differences in the final bone cut accuracy between the 2 groups. The use of adjustable cutting blocks simplifies navigated procedures and may reduce the time required to perform a navigated total knee arthroplasty.

Background Osteochondral lesions are a common sports-related injury for which osteochondral grafting, including mosaicplasty, is an established treatment. Computer navigation has been gaining popularity in orthopaedic surgery to improve accuracy and precision. Hypothesis Navigation improves angle and depth matching during harvest and placement of osteochondral grafts compared with conventional freehand open technique. Study Design Controlled laboratory study. Methods Three cadaveric knees were used. Reference markers were attached to the femur, tibia, and donor/recipient site guides. Fifteen osteochondral grafts were harvested and inserted into recipient sites with computer navigation, and 15 similar grafts were inserted freehand. The angles of graft removal and placement as well as surface congruity (graft depth) were calculated for each surgical group. Results The mean harvesting angle at the donor site using navigation was 4° (standard deviation, 2.3°; range, 1°-9°) versus 12° (standard deviation, 5.5°; range, 5°-24°) using freehand technique ( P < .0001). The recipient plug removal angle using the navigated technique was 3.3° (standard deviation, 2.1°; range, 0°-9°) versus 10.7° (standard deviation, 4.9°; range, 2°-17°) in freehand ( P < .0001). The mean navigated recipient plug placement angle was 3.6° (standard deviation, 2.0°; range, 1°-9°) versus 10.6° (standard deviation, 4.4°; range, 3°-17°) with freehand technique ( P = .0001). The mean height of plug protrusion under navigation was 0.3 mm (standard deviation, 0.2 mm; range, 0-0.6 mm) versus 0.5 mm (standard deviation, 0.3 mm; range, 0.2-1.1 mm) using a freehand technique ( P = .0034). Conclusion Significantly greater accuracy and precision were observed in harvesting and placement of the osteochondral grafts in the navigated procedures. Clinical studies are needed to establish a benefit in vivo. Clinical Relevance Improvement in the osteochondral harvest and placement is desirable to optimize clinical outcomes. Navigation shows great potential to improve both harvest and placement precision and accuracy, thus optimizing ultimate surface congruity.

Purpose The purpose of this study was to compare an open freehand mosaicplasty technique with an arthroscopic technique for the treatment of osteochondral lesions by measuring the instrument deviation, quantifying this deviation, and providing numerical information on the difference in the outcomes of these techniques. Methods Four cadaveric knees were used. Reference markers were attached to the femur, tibia, and donor/recipient site guides. A total of 10 osteochondral grafts were harvested and inserted into recipient sites arthroscopically and 10 similar grafts were inserted freehand. The angles of graft removal and placement were calculated for each of the surgical groups compared. Ostensibly, a navigation system was used as an aid, to measure the graft placement parameters. Results Statistical analysis revealed that there was no statistically significant difference between the arthroscopic method and the freehand method regarding the angle of graft removal at the donor site ( P = .162), recipient site plug removal angle ( P = .731), and recipient site graft placement angle ( P = .630). In the freehand group, the mean angle of graft removal at the donor site was 12°, the mean angle of recipient site plug removal was 10.7°, and the mean angle of recipient site plug placement was 10.6°. Using the arthroscopic technique, the mean angle of graft removal at the donor site was 17.14°, the mean angle of recipient site plug removal was 12.0°, and the mean angle of recipient site graft placement was 10.14°. Conclusions Our study revealed there was no statistically significant difference regarding precision and accuracy during harvesting, recipient site preparation, and plug placement between the 2 techniques. Clinical Relevance Controversy exists whether an open or arthroscopic osteoarticular transfer system (OATS) technique provides superior accuracy. According to our results, there is no statistically significant difference regarding better visualization, precision, and accuracy between the freehand and arthroscopic techniques. However, larger number of specimens are required for study.

Purpose. In this study, the early and midterm clinical and radiological results of the anterior cruciate ligament (ACL) reconstruction surgery with or without the use of platelet rich plasma (PRP) focusing on the tunnel-widening phenomenon are evaluated.Methods. This is a double blind, prospective randomized study. 51 patients have completed the assigned protocol. Recruited individuals were divided into two groups: a group with and a group without the use of PRPs. Patients were assessed on the basis of MRI scans, which were performed early postoperatively and repeated at least one-year postoperatively. The diameter was measured at the entrance, at the bottom, and at the mid distance of the femoral tunnel.Results. Our study confirmed the existence of tunnel widening as a phenomenon. The morphology of the dilated tunnels was conical in both groups. There was a statistical significant difference in the mid distance of the tunnels between the two groups. This finding may support the role of a biologic response secondary to mechanical triggers.Conclusions. The use of RPRs in ACL reconstruction surgery remains a safe option that could potentially eliminate the biologic triggers of tunnel enlargement. The role of mechanical factors, however, remains important.

The purpose of this study was to compare a freehand arthroscopic approach versus mosaicplasty for treatment of osteochondral lesions of the knee with a navigated arthroscopic technique.Four whole cadaveric lower limbs were used. A conventional navigation system was used in combination with an autologous osteochondral graft transplantation system (Osteochondral Autograft Transfer System [OATS]; Arthrex, Naples, FL). The congruity of the articular surface was measured with the navigation probe to detect any difference between the surface created by the grafts and the surface of the femoral condyle surrounding them. The angle relates to a line perpendicular to the articular surface. This line is made by the cutting instrument for graft harvesting and insertion and the articular surface.The mean angle of graft harvest was 3.4° (range, 0° to 10°) in the navigated group versus 14.8° (range, 6° to 26°) in the freehand group (P.0003). The mean angle for recipient-site coring was 1.5° (range, 0° to 5°) in the navigated group versus 12.6° (range, 4° to 17°) in the freehand group (P.0003). The mean angle of graft placement was 2° (range, 1° to 5°) in the navigated group versus 10.8° (range, 5° to 15°) in the freehand group (P = .0002). The mean protrusion height of the plug was 0.23 mm (range, 0.1 to 0.5 mm; SD, 0.16) in the navigated group versus 0.34 mm (range, 0.0 to 0.7 mm; SD, 0.25) in the freehand group (P = .336).Computer-assisted arthroscopic mosaicplasty for treatment of osteochondral lesions in the cadaveric model presented in this study allows permanent visualization of the angle of recipient-site preparation, the depth of the donor plug and the recipient plug, and the angle of insertion of the graft at the recipient site.This study shows evidence of potentially greater precision and reproducibility of navigated arthroscopic mosaicplasty when compared with an arthroscopic freehand technique in a cadaveric model. However, true clinical outcome benefit will only be elucidated upon performance of appropriate clinical studies.

Introduction: In a complete dislocation of the talus, the talus is stripped of all its ligament connections in the triple articulated ankle joint. This case report describes the treatment and the 3-year follow-up of a complete dislocation of the talus with the use of intraoperative 3D imaging. Patients and methods: The 19-year-old patient was involved as a driver in a car accident. After the radiological diagnosis of a complete talus dislocation, an emergency operation was performed due to the critical soft tissue condition. The ISO-C3D fluoroscope from the company Siemens (Erlangen, Germany) was utilized for reduction control. Results: Follow-up evaluations were completed three years after the treatment, the patient had no complaints. Discussion: Since these types of serious injuries are always combined with severe soft tissue damage, the main goals of this treatment have to be debridement and minimized iatrogenic surgical damage. By using intraoperative 3D imaging, immediate reduction control is available, so that revision operations can be avoided. Conclusion: Complete dislocation of the talus is an extremely rare injury, which may cause serious complications. A fast and careful reduction, whether open or closed, should be the goal of treatment. Successful reduction can be determined intraoperatively with the use of 3D imaging.

Computer-navigation in total knee arthroplasty has been reported to increase accuracy but also procedure duration. We compared surgical time and precision using a novel adjustable cutting block vs freehand navigation with conventional blocks on 12 bilateral cadaver tibiae. The mean time required was significantly less to position the adjustable block than the conventional block (2 minutes 10 seconds vs 6 minutes 35 seconds, P = .006). Guide positioning precision (standard deviation) for the adjustable block vs conventional block was as follows: varus/valgus, 0.24 degrees vs 1.16 degrees (P = .015); posterior slope, 0.35 degrees vs 0.74 degrees (P = .13); and cut height, 0.37 vs 1.41 mm (P = .010). There were no significant differences in the final bone cut accuracy between the 2 groups. The use of adjustable cutting blocks simplifies navigated procedures and may reduce the time required to perform a navigated total knee arthroplasty.

Valgus alignment affects the biomechanical behavior of the ACL, resulting in an increase of the in situ forces in the posterolateral (PL) bundle of the graft. The amount of valgus alignment creating such effects on the force remains unclear. Furthermore, the mechanistic rational for the increase in situ forces on the PL bundle when compared with the AM during the valgus osteotomy remained unclear. We hypothesized that increasing valgisation of the knee results in significantly increased obliquity and a resulting increasing elongation pattern and apparent strain of the PL bundle compared to the AM bundle. Six cadaver legs were used utilizing two commercial navigation systems including navigated high tibial osteotomy (HTO) and ACL measurements simultaneously. ACL footprints were registered for the central and identified AM and PL bundle. A stepwise oblique open wedge osteotomy was performed for 7.5° and 15° valgisation. Length changes and coronal plane obliquity were determined at 0° and 30° flexion. The apparent strain for each fiber was calculated. Valgisation significantly affects the length and obliquity of the PL portion of ACL. Valgisation of 7.5° appears to be a threshold for affecting PL length and obliquity without significant changes compared to 15°. The mean apparent strain for the PL bundle increases up to 14% with a 15° osteotomy in full extension, compared to 4% for the central and 2% for the AM bundle. HTO should be done prior to fixation the ACL graft in combined procedures as valgisation does affect graft length. Relative alignment influence on obliquity and length of the PL bundle should be considered in valgus knees.

AIM: To investigate donor site’s area histological and immunohistochemical knee cartilage appearances after resurfacing iatrogenic defects with biosynthetic plugs orautografts. METHODS: Thirty New Zealand White rabbits were used in this study. A full-thickness cylindrical defect of 4.5 mm (diameter) × 7 mm (depth) was created with a hand drill in the femoral groove of every animal. In Group A (n = 10) the defect of the donor site was repaired with a biosynthetic osteochondral plug, in Group B (n = 10) with an osteochondral autograft, while in Group C (control group of 10) rabbits were left untreated. RESULTS: Twenty-four weeks postoperatively, smooth articular cartilage was found macroscopically in some trocleas’ surfaces; in all others, an articular surface with discontinuities was observed. Twenty-eight out of 30 animals were found with predominantly viable chondrocytes leaving the remaining two -which were found only in the control group- with partially viable chondrocytes. However, histology revealed many statistical differences between the groups as far as the International Cartilage Repair Society (ICRS) categories are concerned. Immunofluoresence also revealed the presence of collagen II in all specimens of Group B, whereas in Group A collagen II was found in less specimens. In Group C collagen IIwas not found. CONCLUSION: The matrix, cell distribution, subchondral bone and cartilage mineralization ICRS categories showed statistically differences between the three groups. Group A was second, while group B received the best scores; the control group got the worst ICRS scores in these categories. So, the donor site area, when repairing osteochondral lesions with autografting systems, is better amended with osteochondral autograft rather than bone graft substitute implant.