Postoperative mechanical alignment analysis of total knee replacement patients operated with 3d printed patient specific instruments: A prospective cohort study

Objective: Total knee replacement (TKR) is a surgical treatment for final stage gonarthrosis. The lifespan of the prosthetic implants used in TKR surgery is a major interest for the orthopaedic research community.Previously, proper implant alignment of the implants has been advocated for longevity of the TKR surgery. Recently, patient-specific (PSI) instruments have been proposed to improve the mechanical alignment of the TKR by permitting better implant positioning over conventional TKR surgery. The aim of this study is to compare the mechanical alignment results of patients operated with PSIs and conventional instruments. Methods: Two groups of 20 patients chosen in a quasi-random manner have been compared in this study. In the first group femoral distal and tibial osteotomies were made by a PSI which was produced by the patients’ computed tomography scans. All osteotomies in the control group were made with the TKR set's routine instruments by conventional means. Patients’ preoperative and postoperative mechanical femorotibal angles (mFTA), femoral coronal angles (FCA), tibial coronal angles (TCA) were measured and the number of outliers which showed more than 3° of malalignment were counted in both groups for comparison. Results: The average postoperative mFTA was found to be 2.09° for the PSI group and in was found to be 284° for the control which was not statistically significant. The comparison of postoperative FCA and TCA also did not show significant difference between the groups. The number of outliers showing more than 3° of malalignment per group were found to be 1 out of 20 (5%) for the PSI group and 7 out of 20 (35%) for the control which was statistically significant. Conclusion: In this study patient-specific instrumentation provided significantly better mechanical alignment compared to conventional TKR for the frequency of outlier cases with malalignment beyond 3°. PSI proved no significant difference when the groups were compared for mFTA, FCA and TCA. Our findings support that PSI may improve TKR alignment by improving the ratio of the outlier patients with marked malalignment. Level of Evidence: Level III, Therapeutic Study

The effect of low-molecular-weight heparin on rat tendon healing

Objectives: We investigated the effect of low-molecular-weight heparin (LMWH) on the healing of tendons. Methods: Forty-five adult Wistar rats weighing 300 g were randomized into three groups equal in number. All the rats underwent full-thickness surgical incision of the Achilles tendon followed by primary repair. After the operation, two groups received daily subcutaneous LMWH injections (nadroparin calcium) for four weeks at high or low doses (group 1, 6 mg/kg, 170 IU AXa; group II, 3 mg/kg, 85 IU AXa). Group III remained untreated as the control group. Histologically, the specimens were examined under light and electron microscopy with regard to the amount of fibrillar collagen synthesis, mitochondrial degeneration, and the composition of the extracellular matrix collagen. Biomechanically, maximum load to failure and correspondent elongation of the tendons were measured. Results: Compared to the control group, histologically, both LMWH-treated Groups exhibited increased number of fibroblasts, increased fibrillar collagen formation in the extracellular matrix, and higher counts of granular endoplasmic reticula in cytoplasmic contents of fibroblasts as well as decreased mitochondrial vacuolization and degeneration. Biomechanical assessments showed that tendons in group I had significantly higher maximum load to failure and elongation values than group II and III (31 N vs. 24.6 N and 23.1 N; 25 mm vs. 19.6 mm and 17.3 mm, respectively; p0.05). Conclusion: Daily administration of single dose LMWH improves tendon healing through increasing the number of fibroblasts and fibrillar collagen synthesis and decreasing mitochondrial degeneration.Publisher's Versio

KAVİTER KEMİK DEFEKTLERİNİN İYİLEŞMESİNDE OTOJEN PERİOST VE SERAMİK KOMPOZİT GREFTİNİN ETKİSİ

Amaç: Bu çalışmada, otojen periost parçalarının osteokondüktif sentetik kemik greft alternatifleriyle birlikte kullanımının, kaviter kemik defektlerinin iyileşmesindeki histolojik davranışının incelenmesi amaçlanmıştır. Gereç ve Yöntem: Çalışmada, ortalama ağırlıkları 1000-1500 gr ağırlığında, 8-12 aylık 12 Yeni Zelanda tavşanı kullanıldı. 12 tavşana ait 24 femur eşit sayıda üç gruba ayrıldı. Tüm tavşanlarda, bilateral lateral girişimle, femur suprakondiler bölgede, 5 mm.’lik oyucuyla kaviter defekt oluşturuldu. Grup I’de dört tavşana ait sekiz femur boş bırakılarak kontrol grubu olarak atandı. Grup II’de kalan sekiz tavşanın sağ femurları (sekiz femur) sadece seramik greft granülleriyle dolduruldu. Grup III’de ise ikinci gruptaki tavşanların sol femurları (sekiz femur) seramik greft granülleri ve tibia kaynaklı periost parçaları karışımıyla greftlendi. Seramik olarak Cem-Ostetic™ 5 cc granules (Berkeley Advanced Biomaterials, Inc. CA, U.S.A.) kullanıldı. Grup III’de defektlere konulan otojen periost şeridi deneğin ipsilateral tibia proksimalinin medial yüzünden alındı ve keskin bisturi yardımıyla minimal manuplasyon ile 1-2 mm2’lik parçalara ayrıldı. Denekler postoperatif 6. Haftada feda edildi ve defekteler kemik iyileşmesini değerlendirmek üzrere histolojik incelemeye tabi tutuldu Bulgular: Grup I’de (kontrol grubu) kemik oluşumunun oldukça az gözlendiği, defekt alanın fibröz doku yapısıyla kemiği taklit edercesine kapatıldığı dikkati çekti. Yeni kemiğin varlığı bölgede çok dar alanlarda gözlendi. Grup II’de (seramik grubu) fibröz dokunun aralarında yeni kemik oluşumunun kontrol grubuna göre daha fazla olduğu gözlendi. Kemiğin biçimlendiği bölgelerde damarlar ve osteositler yoğun çekirdekleriyle dikkati çekti. Grup III’de (periost-seramik kompozit) defekt bölgesinde proliferatif kıkırdak oluşumu gözlendi. Bölgede kemik oluşumu diğer gruplara göre daha yoğundu. Fibröz doku bölmeleri son derece azalmıştı. Histomorfometrik yöntemlerle elde edilen ölçümlerin istatistiksel analizi sonucunda, Grup III’de (periost-seramik kompozit) diğer iki gruba göre artmış örgü kemik oluşumu ve daha az fibröz doku oluşumu istatistiksel olarak kanıtlandı. Sonuç: Serbest periost parçalarının seramiklerle harmanlanması ile elde edilen kompozit greftin, hem kontrol grubundan, hem de tek başına seramik uygulanan gruptan çok daha üstün iyileşme performansı sağladığını söyleyebiliriz. Bunun seramiğin kabul görmüş osteokondüktif özelliklerinin, periostun osteojenik özellikleriyle birleştirilmesinin sonucu olduğunu düşünüyoruz. Ek olarak serbest periost parçacıklarının defektin her bölgesinde homojen şekilde bulunmalarını sağlayan uygulama şeklinin de iyileşme performansını olumlu etkilediğini düşünüyoruz.Objective: The aim of this study is to investigate the role of composite graft constituting of free autologue periosteal particles along with osteoconductive ceramic bone graft extenders for the healing of cavitary bone defects. Materials and Method: 12 New Zealand type rabbits aged 8-12 months and weighing approximately 1000-1500 gr were used in this study. 24 femurs of the rabbits were separated to three groups of eight femurs. Bilateral lateral exposure of the femoral condyle was followed by the creation of cavitary defects with the use of an 5mm drill bit. In group I (eight limbs of four animals) the defect was left empty and so was attended as a control. In group II the right lower limbs of the remaining eight animals were only filled with ceramic graft particles. In group III the defects in the left lower limbs of the same animals for group II were filled with both ceramic graft particles and autogenous periosteal particles. The ceramic particles used was Cem-Ostetic™ 5 cc granules (Berkeley Advanced Biomaterials, Inc. CA, U.S.A.). The periosteal particles administered in group III were harvested from the ipsilateral medial tibial metaphysis and were cut in to 1-2 mm2 particles with minimal manipulation. All animals were sacrificed at the end of sixth week and were evaluated histologycally for bone healing. Results: In group I (control) new bone formation was clearly inferior and defect was mostly obliterated with fibrous tissue. In group II (ceramic only) islets of new bone were scattered more frequent in the fibrous tissue background when compared to group I. New vasculature and osteocytes with dense nuclei were present within the newly formed bone tissue. In group III (ceramic and periosteum composite) the defects were obliterated with new bone tissue which was superior to the other groups, along with cartilage proliferation which was not notable in group I and II. The amount of fibrous tissue covered area was clearly less when compared to the control group and ceramic only group. The statistical evaluation of the histomorphometrically gathered quantitative results revealed meaningful increase in woven bone and decrease in fibrous tissue in group III, confirming the histological analysis. Furthermore, cartilage tissue seen only in group III is expected to transform into bone tissue by means of enchondral ossification process. Conclusion: The composite graft constituting of free autologue periosteal particles along with osteoconductive ceramic bone graft extenders appears to be facilitating the bone healing process far bypassing the ceramic bone graft extenders alone. We think that these findings can be owed to the osteoconductive properties of the ceramic graft and osteogenetic properties of periosteum acting in a synergistic behavior. We also think that the application method of the periosteum, which clearly helps to distribute osteogenic potential evenly throughout the defect is yet as important in achieving the results

Analysing the change of sagittal balance in patients with Lenke 5 idiopathic scoliosis

Objective: The aim of this study was to evaluate preoperative and postoperative spinopelvic parameters and the influence of lowest instrumented vertebrae on sagittal parameters in Lenke 5 Adolescent Idiopathic Scoliosis (AIS) patients. Methods: A total of 42 patients (37 females, 5 males; mean age: 16.71 ± 3.46 years) were included in the study. Preoperative and postoperative last follow up lumbar lordosis (LL), thoracic kyphosis (TK), pelvic tilt (PT), pelvic incidence (PI) and sacral slope (SS) angles measured. By stopped fusion in L3, L4 or L5 we divided the group into three parts. Results: Mean follow-up was 43 months. Preoperatively, the mean TK and LL were 36.8° and 55.3°. At the last follow up, the mean TK and LL were 27.1° and 49.0° degrees, respectively. Preoperatively, the mean PI, PT and SS were 53.3°, 16.1° and 37.4° degrees. At the last follow up, the mean PI, PT and SS were 52.7°, 19.9° and 33.0° respectively. Significant differences were observed for SS (p = 0.003), TK (p = 0.004), LL (p = 0.012) and PT (p = 0.013) postoperatively for all patients. According the L3 and L4 groups there is significant difference in SS, LL (p = 0.013) and PT (p = 0.018) which means a significant decrease occurs in SS and LL when the distal fusion level changes from L3 to L4 but significant increase in PT in L3 group to compensate spinopelvic change after surgery. Conclusion: The selection of more distal level for fusion adversely affects the compensation mechanisms of sagittal balance in Lenke 5 AIS patients. Level of Evidence: Level IV, Therapeutic study. Keywords: Lenke 5, Scoliosis, Sagittal, Spinopelvic, Compensat

Lenke 5 curves. Is thoracic fusion really necessary?

Objective: The recommended surgery for Lenke type 5 curve is only the fusion of structural curve (SF: Selective fusion). However, some surgeons prefer to fuse both the thoracolumbar and lumbar (TL/L) curve and the non-structural thoracic (T) curve (NSF: Non-selective fusion). There is a lack of data with regard to the mid-to-long-term outcomes of the SF and NSF. In this study, it was aimed to compare SF and NSF in terms of TL/L and T curve correction rates and the prognosis of the corrected curves. Materials and Methods: A retrospective study of AIS patients treated at a single institution was conducted. A total of 59 patients (55F/M4) were included in the study. Preoperative, early postoperative, and last follow-up TL/L Cobb and T Cobb angles were measured with software. SF and NSF correction rate comparison was done using the Mann-Whitney U test. Results: Overall, 35 patients underwent NSF while 24 patients underwent SF. The mean follow-up duration was 43±18.05 months (54-98). Early T Cobb correction rate was 69% in group 1 (SF) and 79% group 2 (NSF); however, this difference was not statistically significant when the groups were compared (p=0.71138). The last follow-up T Cobb correction rates for group 1 and group 2 were 66% and 79%, respectively (p=0.5485). Early TL/ L Cobb correction rate was 78% in group 1 and it was 79% in group 2 (p=0.8493). Last follow-up TL/L Cobb follow-up correction rates for groups were 79% and 76%, respectively (p=0.9203).Conclusion: This study concluded that SF had favorable outcomes without loss of correction for the patients with Lenke type 5C AIS in the mid-to-long-term.Keywords: Lenke type 5C AIS, selective fusion, non-selective fusion, loss of correction, prognosi

Quantitative comparison of a laterally misplaced pedicle screw with a re-directed screw. How much pull-out strength is lost?

Objective: Redirecting of a laterally misplaced pedicle screw into the accurate position decreases the pull-out strength due to the reinsertion, lateral wall cortical perforation and widening of the pedicle hole. Thus, this biomechanical study was performed to quantitatively analyze the pullout strength of a redirected laterally misplaced pedicle screw into the accurate position

Comparison of effectiveness of kyphoplasty and vertebroplasty in patients with osteoporotic vertebra fractures

Objective: The aim of this study was to compare the functional and radiological outcomes of vertebroplasty and kyphoplasty in patients with osteoporotic vertebra fractures. Methods: The files of the patients who underwent vertebroplasty or kyphoplasty for osteoporotic vertebrae fractures were retrieved from the archives. Forty-three patients with complete follow-up data were included in the study group. The patients were evaluated for radiological outcomes in terms of local kyphosis angle, wedging index, compression ratio, visual analog pain scale (VAS) and Oswestry Disability Index (ODI). Results: In the study group, kyphoplasty was performed on 24 vertebrae of 22 patients (17 females, 5 males; mean age: 73 years) whereas vertebroplasty was applied on 24 vertebrae of 21 (16 females, 5 males; mean age: 74.7 years) patients. The mean follow-up time was 26 months. When the VAS and ODI values of the groups were analyzed, both groups showed statistically significant progress after the operation. Radiological data showed that the kyphoplasty group showed statistically significant improvement in the sagittal index values whereas the vertebroplasty group did not. The overall complication ratio was 4\%. Conclusion: Both vertebroplasty and kyphoplasty are effective treatment methods for functional recovery and pain relief in osteoporotic fractures of the vertebra. Although radiological outcomes of the kyphoplasty seem to be better, this does not have any clinical relevance. We suggest vertebroplasty over kyphoplasty since it is an easier method to manage. (C) 2016 Turkish Association of Orthopaedics and Traumatology. Publishing services by Elsevier B. V. This is an open access article under the CC BY-NC-ND license