Automated patellar height assessment on high-resolution radiographs with a novel deep learning-based approach

BACKGROUND Artificial intelligence and deep learning have shown promising results in medical imaging and interpreting radiographs.Moreover,medical community shows a gaining interest in automating routine diagnostics issues and orthopedic measurements.AIM To verify the accuracy of automated patellar height assessment using deep learning-based bone segmentation and detection approach on high resolution radiographs.METHODS 218 Lateral knee radiographs were included in the analysis.82 radiographs were utilized for training and 10 other radiographs for validation of a U-Net neural network to achieve required Dice score.92 other radiographs were used for automatic(U-Net)and manual measurements of the patellar height,quantified by Caton-Deschamps(CD)and Blackburne-Peel(BP)indexes.The detection of required bones regions on high-resolution images was done using a You Only Look Once(YOLO)neural network.The agreement between manual and automatic measurements was calculated using the interclass correlation coefficient(ICC)and the standard error for single measurement(SEM).To check U-Net's generalization the segmentation accuracy on the test set was also calculated.RESULTS Proximal tibia and patella was segmented with accuracy 95.9%(Dice score)by U-Net neural network on lateral knee subimages automatically detected by the YOLO network(mean Average Precision mAP greater than 0.96).The mean values of CD and BP indexes calculated by orthopedic surgeons(R#1 and R#2)was 0.93(±0.19)and 0.89(±0.19)for CD and 0.80(±0.17)and 0.78(±0.17)for BP.Automatic measurements performed by our algorithm for CD and BP indexes were 0.92(±0.21)and 0.75(±0.19),respectively.Excellent agreement between the orthopedic surgeons’measurements and results of the algorithm has been achieved(ICC>0.75,SEM<0.014).CONCLUSION Automatic patellar height assessment can be achieved on high-resolution radiographs with the required accuracy.Determining patellar end-points and the joint line-fitting to the proximal tibia joint surface allows for accurate CD and BP index calculations.The obtained results indicate that this approach can be valuable tool in a medical practice.

Horizontal Inferior Patellar Dislocation in an Elderly Patient: A Case Report and Review of Literature

Intra-articular patellar dislocation due to acute trauma is considered a rare presentation and is less commonly encountered in practice than extra-articular patellar dislocation. This case study presents a rare type 2 inferior dislocation of the patella in an elderly patient which was successfully reduced and managed non-operatively.

Anterolateral rotatory instability in vivo correlates tunnel position after anterior cruciate ligament reconstruction using bone-patellar tendon-bone graft

AIM To quantitatively assess rotatory and anterior-posterior instability in vivo after anterior cruciate ligament(ACL) reconstruction using bone-patellar tendon-bone(BTB) autografts, and to clarify the influence of tunnel positions on the knee stability.METHODS Single-bundle ACL reconstruction with BTB autograft was performed on 50 patients with a mean age of 28 years using the trans-tibial(TT)(n = 20) and trans-portal(TP)(n = 30) techniques. Femoral and tibial tunnel positions were identified from the high-resolution 3 D-CT bone models two weeks after surgery. Anterolateral rotatory translation was examined using a Slocum anterolateral rotatory instability test in open magnetic resonance imaging(MRI) 1.0-1.5 years after surgery, by measuring anterior tibial translation at the medial and lateral compartments on its sagittal images. Anterior-posterior stability was evaluated with a Kneelax3 arthrometer.RESULTS A total of 40 patients(80%) were finally followed up. Femoral tunnel positions were shallower(P < 0.01) and higher(P < 0.001), and tibial tunnel positions were more posterior(P < 0.05) in the TT group compared with the TP group. Anterolateral rotatory translations in reconstructed knees were significantly correlated with the shallow femoral tunnel positions(R = 0.42, P < 0.01), and the rotatory translations were greater in the TT group(3.2 ± 1.6 mm) than in the TP group(2.0 ± 1.8 mm)(P < 0.05). Side-to-side differences of Kneelax3 arthrometer were 1.5 ± 1.3 mm in the TT, and 1.7 ± 1.6 mm in the TP group(N.S.). Lysholm scores, KOOS subscales and reinjury rate showed no difference between the two groups.CONCLUSION Anterolateral rotatory instability significantly correlated shallow femoral tunnel positions after ACL reconstruction using BTB autografts. Clinical outcomes, rotatory and anterior-posterior stability were overall satisfactory in both techniques, but the TT technique located femoral tunnels in shallower and higher positions, and tibial tunnels in more posterior positions than the TP technique, thus increased the anterolateral rotation. Anatomic ACL reconstruction with BTB autografts may restore knee function and stability.

Three-dimensional photoelasticity analysis of Nitinol Patellar Concentrator for treating patellar fractures

Objective: To analyze the biomechanical elements of Nitinol Patellar Concentrator (NT-PC) in heating commi nuted patellar fractures. Methods: The epoxy resin three dimensional photoelasticity pobal model was loaded with Nitinol Patellar Connector and frozen. After dividing layer, photographing and tracing, iterative method was used to calculate the stress value of every tuteed node. Rasults: Stress values of 1 262 nodes scattered in 12 layers were obtained The stress distribution indicated that an overall stress field was yield when the NT-PC fixated the patellar model, and there existed fixative stress in the facies articularis and distal pole of the patellar model. Conclusion: The NT-PC has evident therapeutic effect for the comminuted patellar fractures. The existing stress is helpful in maintaining anatomical reduction and enhancing fracture healing.

Early patellar tendon rupture after total knee arthroplasty: A direct repair method

BACKGROUND Patellar tendon rupture after total knee arthroplasty(TKA)is a catastrophic complication.Although the occurrence of this injury is rare,it can lead to significant dysfunction for the patient and is very tricky to deal with.There has been no standard treatment for early patella tendon rupture after TKA,and long-term follow-up data are lacking.AIM To introduce a direct repair method for early patella tendon rupture following TKA and determine the clinical outcomes and complications of this method.METHODS During the period of 2008 to 2021,3265 consecutive TKAs were retrospectively reviewed.Twelve patients developed early patellar tendon rupture postoperatively and were treated by a direct repair method.Mean follow-up was 5.7 years.Demographic,operative,and clinical data were collected.The clinical outcomes were assessed using the Western Ontario and McMaster Universities(WOMAC)score,the Hospital for Special Surgery(HSS)score,knee range of motion,extensor lag,and surgical complications.Descriptive statistics and paired t test were employed to analyze the data.RESULTS For all 12 patients who underwent direct repair for early patellar tendon rupture,3 patients failed:One(8.3%)for infection and two(17.6%)for re-fracture.The two patients with re-fracture both underwent reoperation to reconstruct the extensor mechanism and the patient with infection underwent revision surgery.The range of motion was 109.2°±10.6°preoperatively to 87.9°±11°postoperatively,mean extensor lag was 21°at follow-up,and mean WOMAC and HSS scores were 65.8±30.9 and 60.3±21.7 points,respectively.CONCLUSION This direct repair method of early patellar tendon rupture is not an ideal therapy.It is actually ineffective for the recovery of knee joint function in patients,and is still associated with severe knee extension lag and high complication rates.Compared with the outcomes of other repair methods mentioned in the literature,this direct repair method shows poor clinical outcomes.

Repair of a large patellar cartilage defect using human umbilical cord blood-derived mesenchymal stem cells:A case report

BACKGROUND Patellar dislocation may cause cartilage defects of various sizes.Large defects commonly require surgical treatment;however,conventional treatments are problematic.CASE SUMMARY A 15-year-old male with a large patellar cartilage defect due to patellar dislocation was treated via human umbilical cord blood-derived mesenchymal stem cell(hUCB-MSC)implantation.To our knowledge,this is the first report of this treatment for this purpose.The patient recovered well as indicated by good visual analog scale,International Knee Documentation Committee and McMaster Universities Osteoarthritis Index scores.Magnetic resonance imaging showed cartilage regeneration 18 mo postoperatively.CONCLUSION Umbilical cord blood-derived hUCB-MSCs may be a useful treatment option for the repair of large patellar cartilage defects.

Tibial tuberosity avulsion-fracture associated with complete distal rupture of the patellar tendon:A case report and review of literature

BACKGROUND Few cases of avulsion fractures of the tibial tuberosity with simultaneous rupture of the patellar tendon have been reported in the literature.Therefore,its mechanism and incidence have not been determined conclusively.This type of fracture is considered a serious injury that requires prompt diagnosis and early surgical repair.There is no therapeutic algorithm or standard method of treatment due to the infrequency of the injury.In this case report,we conducted an exhaustive review and synthesis of the existing literature including all previously reported cases.CASE SUMMARY We present a 16-year-old male soccer player with a case of a tibial tuberosity fracture with distal avulsion of the patellar tendon 5 d prior to surgical treatment.The patient presented with a loss of the extensor mechanism of the knee,edema,the inability to walk,and pain.X-rays showed a high patella and a 180-degree avulsion of the tibial tuberosity.The diagnosis was confirmed by magnetic resonance imaging and computed tomography.The patient underwent open reduction and internal fixation of the fracture with a cannulated screw and washer as well as patellar tendon repair with two metallic anchors.The rehabilitation protocol consisted of initial immobilization in extension followed by passive mobility and muscle strengthening exercises.The patient demonstrated excellent postoperative outcomes and returned to regular activity without complications.CONCLUSION This case presentation and literature review comprise the most relevant clinical,radiographic,and treatment details described in the international literature to date,providing the reader with an overview of this rare condition.

Patellar dislocation following distal femoral replacement after extraarticular knee resection for bone sarcoma:A case report

BACKGROUND For the treatment of bone sarcoma in the distal femur,wide-margin resection and knee reconstruction with tumor endoprosthesis are standard therapies.Extraarticular knee resection is required in cases of tumor invasion of the knee joint;however,the incidence of complications,such as aseptic loosening,prosthesis infection,and implant failure,is higher than that following intra-articular knee resection.To the best of our knowledge,there are three reports of patellar dislocations after replacement of a tumor endoprosthesis.CASE SUMMARY A 36-year-old man with no significant past medical history was admitted to our institution with continuous pain in his left knee for 4 mo.An open biopsy was performed,and the patient was diagnosed with a left distal femoral malignant bone tumor.Extra-articular knee resection and knee reconstruction with a tumor endoprosthesis were performed.Although the alignment of the tumor prosthesis was acceptable,knee instability was noticed postoperatively.The axial radiographic view of the patellar and computed tomography showed lateral patellar dislocation at 4 wk postoperatively.The patient had to undergo a lateral release and proximal realignment.He could perform his daily activities at 9 mo postoperatively.Radiography revealed no patellar re-dislocation.CONCLUSION Proximal realignment may be considered during primary surgery if there is an imbalance in the forces controlling the patellar tracking.

New treatment of patellar instability after total knee arthroplasty: A case report and review of literature

BACKGROUND Patellar instability is an uncommon complication after total knee arthroplasty(TKA).Partial lateral patella facetectomy(LPF)with lateral retinaculum release treatment of patellar instability is rarely reported.CASE SUMMARY We present a case of patellar instability 8 mo after primary TKA.Treatment of this complication was adapted to address the cause of the dislocation.To eliminate patellar instability,we restored the vastus medialis and performed LPF with lateral retinaculum release.We achieved normal patellar tracking.Clinical and radiographic evaluations at the 1-year postoperative follow-up were satisfactory.CONCLUSION LPF with lateral retinaculum release represents a promising option to restore central patellar tracking in patients with patellar instability after TKA in cases without component malposition.

Patellar Tendinopathy: A Physiotherapist’s Perspective

The pathology of patellar tendinopathy and the mechanisms of pain are poorly understood. The most popular treatment modality is the Eccentric overload Exercise. However, there is insufficient evidence to recommend a specific protocol and yet it is the most commonly used treatment modality. The aim of this case study is to present the possible mechanisms of pain and a treatment approach on a patient who was diagnosed as having patellar tendinopathy. It is suggested that hyper extension of the knee might be the source of patellar tendon pain in this patient. Following a course of pulsed short wave diathermy the patient was symptom free and remained so at 6 month review. Further studies to evaluate effectiveness of pulsed short wave diathermy is suggested.

Internal fixation and unicompartmental knee arthroplasty for an elderly patient with patellar fracture and anteromedial osteoarthritis:A case report

BACKGROUND Open reduction and internal fixation(ORIF)is the traditional surgical treatment for patellar fractures,and unicompartmental knee arthroplasty(UKA),especially Oxford UKA,has been increasingly used in patients with medial knee osteoarthritis(OA).However,the process of choosing treatment for patients with both patellar fractures and anteromedial knee OA remains unclear.We present the case of a patient with a patellar fracture and anteromedial OA.CASE SUMMARY We present the case of a 72-year-old woman with a history of bilateral medial compartment OA of the knees and a right Oxford UKA.She also experienced a recent left patellar fracture.ORIF and Oxford UKA were performed in a single stage.The patient showed excellent postoperative clinical results.CONCLUSION ORIF and Oxford UKA can be performed simultaneously for patients with patellar fracture and anteromedial OA on the same knee.

Ablation of a Patellar Button by Arthroscopy

Fracture of the patella after total knee arthroplasty is an infrequent complication. In the presence of poor remaining bone stock, avascular necrosis, removal of the implant with partial or complete patellectomy is recommended. Arthroscopic removal of a loose body or cement extrusion has been recently attempted successfully in very few cases, where loose and mobile cement fragments were involved and were often removed piecemeal. The authors experienced an unusual case of a patient a 69-year-old woman who, after having fallen down, presented a comminuted patellar fracture. We recommended an external orthosis and a temporary limitation of activity. Four months later, the patient complained. An X-ray revealed a necrosis of the proximal fragment and a lowering of the patellar button with the distal bone fragment. The removal of the patellar button was performed by arthroscopy. Conservative treatment can be successful for this patients and the removal of the patellar button loosening via arthroscopy appears to be an attractive technique to be used in similar cases.

Ligament augmentation reconstruction system artificial ligaments in patellar tendon reconstruction-a chronic patellar tendon rupture after multiple operations: A case report

BACKGROUND Patellar tendon rupture is a rare disease,and reports regarding patellar tendon reconstruction with ligament augmentation reconstruction system(LARS)ligaments are limited,with only three reports available in the literature.LARS ligaments are made of polyethylene terephthalate and have been certified as a more favorable option than other tendon transplants.To our knowledge,this is the first report of patellar tendon reconstruction with LARS for suture fixation due to poor quality of the tendon after multiple operations to enable early mobilization and quick rehabilitation.CASE SUMMARY A 65-year-old woman had limited ability in extending her leg and an inability to perform a straight leg raise after multiple operations due to patella fracture.The patient underwent patellar tendon reconstruction with LARS artificial ligaments.After 12 mo of follow-up,the patient was able to perform a straight leg raise,and the incision healed well without complications.The Lysholmscore was 95 and the range of motion of the knee was 0-130°.CONCLUSION This study revealed that patellar tendon reconstruction with LARS artificial ligaments is possible in a patient with a patellar tendon rupture who required rapid postoperative recovery.

MRI Observations of Patellar Tendon Length Change after ACL Reconstruction with Hamstring Autografts

The post-operative patellar tendon length was studied to evaluate the possible tendon length change after anterior cruciate ligament（ACL） reconstruction with hamstring autografts. The Insall-Salvati index, modified Insall-Salvati index, curved modified Insall-Salvati index and Caton-Deschamps index were observed by MRI during a follow-up period of 12 weeks on 20 ACL reconstructed knees. The results showed no patellar baja or alta pre-existed on those ACL injured patients. After a follow-up period of 12 weeks, no patellar tendon length change was observed. It is suggested that the change of patella was not the primary reason that may contribute to the premature patellofemoral joint osteoarthritis after ACL reconstruction.

Evidence-based Care for Rehabilitation Nursing Effect of Patients with Patellar Fracture

Objective.To analyze the effect of applying evidence-based care in rehabilitation nursing effect of patients with patellar fractures.Methods.A total of 54 patients with patellar fractures were randomly selected from the hospital.The diagnosis and treatment time were from the beginning of July 2018 to end of June 2019.The digital table grouping was adopted to divide patients into two groups with each group consists of 27 patients with this disease.Both groups underwent routine nursing and the experimental group with increased evidence-based care.Results.Compared with the control group,the knee function evaluation,complications and nursing satisfaction of the experimental group were more ideal,and the difference was statistically significant(P<0.05).Conclusion.Evidence-based care in rehabilitation nursing of patients with patellar fracture can obtain ideal nursing effect.

Comparison of joint function and trauma severity after arthroscopic headless compression screw fixation and conventional open reduction and internal fixation treatment of patellar transverse fracture

Objective:To study the differences in joint function and trauma severity after arthroscopic headless compression screw fixation and conventional open reduction and internal fixation treatment of patellar transverse fracture.Methods: 58 patients with patellar transverse fracture who accepted operative treatment in our hospital between August 2012 and December 2015 were collected and divided into open surgery group (n=30) and arthroscopic surgery group (n=28) according to the surgical approach. Before operation and 3 months after operation, the knee joint function of two groups of patients was evaluated respectively;3 d after operation, enzyme-linked immunosorbent assay (ELISA) was used to detect serum pain mediators, stress hormones and other trauma-related indicators.Results:Differences in the knee joint function index levels were not statistically significant between two groups of patients before operation (P>0.05);3 months after operation, the maximal knee joint flexibility and maximal extension levels of arthroscopic surgery group were higher than those of open surgery group (P<0.05);3 d after operation, serum prostaglandin (PGI2), dopamine (DA), neuropeptide Y (NPY), substance P (SP), glucocorticoid (Cor), renin (R), angiotensin 1 (Ang1), angiotensin 2 (Ang2), epinephrine (E), norepinephrine (NE) and aldosterone (ALD) levels of arthroscopic surgery group were significantly lower than those of open surgery group (P<0.05).Conclusions:Arthroscopic headless compression screw fixation can optimize the knee joint function and reduce the surgical trauma in patients with patellar transverse fracture.

Clinical study of polydloxanone suture tension band fixation for treatment of patellar fractures

To explore biomechanic characteristics and clinical outcome of absorbable polydloxanone (PDS) treating patellar fractures.Methods The tensile strength test of PDS 0-0 or PDS 1-0 sutures were made in WDW305 electro-universal tester.A total of 60 cases were classified randomly and equally into two groups:treatment group (treated with the absorbable PDS tension hand) and Kirschner wire metals tension band control group (control group).Anatomy reduction was performed with towel clip fixation during operation.Treatment group was managed with diameter 1.5 mm Kirschner wires drilling two pores on the near or distal segment of patellar fracture end are penetrating through two strands of absorbable PDS 0-0 or PDS 1-0 sutures for a satisfactory fracture fixation.Control group was treated with Kirschner wires (2.0 mm in diameter) and steel wire (1.0 mm in diameter) of type “8” tension band fixation.Results Tensile strength testing showed that the biggest tensile of a strand PDS 0-0 sutures was 71.50 N and that of PDS 1-0 97.48 N,when the length was three times more than the initial.Two groups were followed up and the mean fracture healing time was two months,without broken wire or dislocation.Treatment group showed excellent clinical results in 21 cases,good in six and fair in three;while control group showed excellent clinical results in 19 cases,good in seven and fair in four,with no statistical difference compared with treatment group (χ2=0.32,P>0.05).Conclusion Absorbable PDS tension band has better characteristics of mechanics and creepage in treating patellar fractures.It can avoid defects of secondary operation and complications like needle-tail pain and sharped skin resulted from metal tension band fixation.Meanwhile,it is economic and worthy of further clinical application.16 refs,4 figs.

Relationship of cyclic stretching of human patellar tendon fibroblasts with abnormal increase of prostaglandins E2 and leukotriene B4

To investigate the relationship between tendinopathy and higher production of prostaglandins E2 (PGE2) and leukotriene B4(LTB4) induced by cyclic stretching of human patellar tendon fibroblasts.Methods We used a novel in vitro model system to mimic in vivo conditions,where human patellar tendon fibroblasts (HPTFs) were uniaxially stretched with different magnitudes of stretching (4%,8% and 12%).Non-stretched fibroblasts were used as control.The productions of PGE2 and LTB4 as well as the expression of cycloxygenase (COX) and 5-lipoxygenase (5-LO) were then measured every four hours of cyclic stretching.In addition,we treated the cells with inhibitors of COX or 5-LO.Results It was found that cyclic stretching of fibroblasts at 8% and 12% of stretching increased PGE2 and LTB4 levels.Blocking the COX enzyme with indomethacin (25 mol/L) decreased PGE2 levels but increased LTB4 production and vice versa.Whereas decreasing LTB4 production with MK-886 (10 μmol/L) could increase PGE2 levels compared to cells tretched without inhibitors.Conclusion Cyclic stretching of HPTFs produces high levels of PGE2 and LTB4,where a balance exists:blocking PGE2 production increases the production of LTB4,and vice versa.Therefore,this study raises the possibility that the routine use of COX inhibitors in clinical treatment of tendinopathy may exacerbate the condition by causing neutrophil-mediated inflammatory and degenerative changes in the tendon due to increased levels of LTB4,which is a potent chemoattractant for neutrophils.17 refs,3 figs.

Comparative study of various internal fixation methods for treating patellar fractures by three-dimensional photoelasticity

Objective: To compare the biomechanical basis of 3 different internal fixation methods: nitinol patellar concentrator (NT-PC), tension band and wire circle in treating patellar fractures. Methods: The epoxy resin three dimensional photoelasticity patellar models were made by precise moulding, and were fixated by nitinol patellar concentrator (NT-PC), tension band and wire circle respectively. The patellar models with frozen stress stripes were put into the polarized light field and the stress distributions were compared. As for the model fixated by NT-PC, by dividing layer, photographing and tracing, we used the iterative method to calculate the stress value of every internal node of the epoxy resin patellar model, and the character of stress was analyzed. Results: An overall stress field was yielded when the patellar model was fixated by NT-PC, and the stripes were more than that of tension band model and wire circle model, which have only few stress stripes in the fixated layers. Further analysis indicated that there were continuous fixated stresses in the facies articularis and distal pole of patella, and the character of stresses produced by NT-PC were mainly in longitudinal direction, then in transverse direction. The shearing stresses were small. Conclusion: The initiative and continuous memorial stress of NT-PC and its overall stress distribution character are the essence of NT-PC distinguished with tension band and wire circle in treating patellar fractures. The stress character produced by NT-PC is good for the stability of fracture site and prompts fracture healing.

Comparison of a minimally invasive osteosynthesis technique with conventional open surgery for transverse patellar fractures

Parpose:The study aims to compare the efficacy and safety of a new minimally invasive osteosynthesis technique with those of conventional open surgery for transverse patellar fractures.Methods:It was a retrospective study.Adult patients with closed transverse patellar fracture were included,and with open comminuted patellar fracture were excluded.These patients were divided into minimally invasive osteosynthesis technique(MIOT)group and open reduction and internal fixation(ORIF)group.Surgical time,frequency of intraoperative fluoroscopy,visual analogue scale score,flexion,extension,Lysholm knee score,infection,malreduction,implant migration and implant irritation in two groups were recorded and compared.Statistical analysis was performed by the SPsS software package(version 19).A p<0.05 indicated statistical significance.Results:A total of 55 patients with transverse patellar fractures enrolled in this study,the minimally invasive technique was performed in 27 cases,and open reduction was performed in 28 cases.The surgical time in the ORIF group was shorter than that in the MIOT group(p=0.033).The visual analogue scale scores in the MIOT group were significantly lower than those in the ORIF group only in the first month after surgery(p=0.015).Flexion was restored faster in the MIOT group than that in the ORIF group at one month(p=0.001)and three months(p=0.015).Extension was recovered faster in the MIOT group than that in the ORIF group at one month(p=0.031)and three months(p=0.023).The recorded Lysholm knee scores in the MIOT group were always greater than those in the ORIF group.Complications,such as infection,malreduction,implant migration,and implant irritation,occurred more frequently in the ORIF group.Conclusion:Compared with the ORIF group,the MIOT group reduced postoperative pain and had less complications and better exercise rehabilitation.Although it requires a long operation time,MIOT may be a wise choice for transverse patellar fractures.