Knee Extensor Mechanism Research Articles

Traumatic Complete Loss of Knee Extensor Mechanism and Its Reconstruction With a Fresh-frozen Patellar Allograft With Patellar and Quadriceps Tendon.

We report on an 18-year-old female who sustained complete loss of her knee extensor mechanism (patella, quadriceps and patellar tendon) due to a motorbike injury with severe soft tissue loss of the ventral aspect of the knee and subsequent infection. After infection control and successful latissimus dorsi free flap surgery, reconstruction of the knee extensor mechanism was performed using a fresh frozen extensor mechanism allograft with patella, quadriceps- and patellar tendon and integrated tibia tuberosity fragment. After a follow-up of 18 months, there was infection free integration of the allograft with a range of motion 0-0-90° (extension/flexion) and pain free gait.

Patellar Tendon Reconstruction Using Hamstring Graft: A Case Report

Background: Patellar tendon ruptures presenting in a chronic setting are rare events that impose technical surgical challenges due to proximal retraction of the patella, quadriceps muscle atrophy and contracture, and peripatellar adhesions. Various reconstruction techniques have been described using different grafts and fixation methods; however, there is a paucity of reported out- comes and there is no consensus on standard of care. Indications: The patient is a young female of 18yrs who presented with a history of trauma to right knee and was diagnosed with chronic patellar tendon tear. The patient was indicated for patellar tendon reconstruction with autologous hamstring tendon graft due to chronicity of the injury. Method: Patellar tendon reconstruction using hamstrings graft and fixing with anchor suture and interference screw. Result: Achieving normal patella tendon height and complete range of motion with restoration of extensor mechanism of knee. Conclusion: Knee extensor mechanism disruptions necessitate prompt surgical correction. In patients with poor tendon quality and/or a history of knee arthroplasty, primary repair should be supplemented with autograft or allograft. Early repairs yield better results than late interventions, which necessitate intricate reconstructions to reestablish the extensor mechanism's continuity. Achieving early osteointegration of the graft is important in case of tendon reconstructive procedures such as in this case as it leads to better outcomes in terms of rehabilitation and early progress to daily activities. Keys Words: tendon injuries, patellar tendon reconstruction, chronic patellar tendon tear, hamstring graft, hamstring tendon autograft, interference screw

Patellar Tendon Debridement and Reconstruction With Hamstring Tendon Autografts in the Setting of Severe Patellar Tendinopathy

Background: Patellar tendinopathy is a multifactorial condition characterized by micro-degenerative changes in the patellar tendon. This results from repeated stress to the knee extensor mechanism from explosive movement, axial malalignment, and/or abnormal patellar height. Currently, there is no standard surgical procedure for the treatment of severe patellar tendinopathy. Indications: Patellar tendon reconstructions for patellar tendinopathy may be indicated when >50% of the tendon attachment is degenerative and detached from the distal patella and non-operative treatment, like physical therapy, bracing, and injections, have not relieved symptoms. Debridement may not offer long-term viability against augmentation of the patellar tendon with autografts, with a risk of recurrent breakdown of the patellar tendon attachment with resumption of previous activities that initially lead to overload. Technique Description: An anterior incision was made from the superior pole of the patella to the tibial tubercle. Then, dissection was performed medially to harvest the gracilis and semitendinosus tendons. Open harvesters were used, and the hamstring tendons were released proximally, keeping the tibial insertions attached. A horizontal pin was drilled across the tibial tubercle and reamed with a 4.5 mm reamer. A passing stitch was fed through the tunnel. The proximal and distal margins of the patella were localized with spinal needles and a pin was drilled across its midportion, 5 mm deep to the dorsal cortical margin, and then rearmed. Degenerative tissue at the patellar tendon was excised. The gracilis tendon was passed medial to lateral through the tibial tubercle, and a Q-Fix anchor anchored the grafts medially and laterally. The semitendinosus graft was passed medial to lateral through the patella followed by the gracilis tendon lateral to medial. Appropriate reconstruction graft tension was confirmed and grafts were whipstitched together. Results: Clinical outcomes for the debridement of severe patellar tendinopathy report 77% symptomatic relief. With many unable to return to activity, patellar tendon reconstruction can be indicated. Outcomes for reconstructions for severe patellar tendinopathy are not reported. Discussion: Patellar tendon reconstruction with hamstring autografts for the treatment of severe patellar tendinopathy can provide a strong reconstruction graft to allow for the resumption of high-level activities. Patient Consent Disclosure Statement: The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.

A Systematic Review of Clinical Outcomes of Pedicled Flap Repairs of the Knee Extensor Mechanism.

Rupture of the extensor mechanism of the knee has severe functional morbidity, and repair can be complicated by infection, allograft degeneration, and recurrent rupture. Techniques of autologous tissue repair utilizing pedicled flaps such as the gastrocnemius offer vascularized methods of reconstruction, with potentially diminished complication rates. The goal of this study was to evaluate the functional outcomes and complications associated with pedicled flap repair of the knee extensor mechanism. A systematic review was conducted following the Preferred Reporting Items for Systemic Reviews and Meta-Analyses guidelines. Publications that focused on local myocutaneous flaps as a means for reconstruction were included. Causes for knee extensor mechanism deficit, flap characteristics, ambulation rate, changes in range of motion pre- and postoperation, and postoperative complications were analyzed. Technique reports including primary suture repairs, synthetic mesh, and allograft use were excluded. An initial 119 studies were identified, with final review of 22 observational studies encompassing 128 cases of pedicled flap reconstructions. The gastrocnemius (88.2%, n = 113), quadriceps (6.3%, n = 8), and a combination of the vastus and gastrocnemius flaps (5.5%, n = 7), were the most frequently utilized flaps. Functional outcomes were favorable with 87.2% of patients achieving ambulation without external support. Variability in range of motion outcomes across different flap may be secondary to the patient characteristics as well as extent of initial injury. Autologous pedicle flap reconstruction of the knee extensor mechanism emerges as a viable option for cases characterized by extensive defects and insufficient soft tissue coverage, which are not amenable to direct suture repairs or allografts. Postoperative assessments revealed that the majority of patients experienced improved ambulation status, with no instances of deterioration noted among the patients.

Gait analysis of patients undergoing knee endoprosthesis: functional differences between tibia and femur resections.

With the improvement in survival of patients undergoing knee reconstructive surgeries, the functional parameter became widely studied heading optimize and minimize motor sequelae. In patients undergoing knee endoprosthesis, proximal tibial or distal femoral resections affect the functioning of the knee extensor mechanism, with possible repercussions on gait. Seventeen patients were selected, divided into two groups, undergoing distal femoral or proximal tibial resection, and gait analysis examination was performed. Changes in gait velocity, cadence, step length, and alterations in the support and balance phase were observed. No major statistically significant differences were found in the kinetic and kinematic parameters between the operated groups. The study corroborates that although tibial resections have a higher theoretical risk of compromising the extensor mechanism, such data were not observed in the analyzed sample.

Prevalence of Jumpers Knee in Basketball Players

Jumpers knee is a painful condition caused due to small tears in the patellar tendon. it mainly occurs in sports requiring strenuous activities which results in localized pain and tenderness of patella .It is also known as patellar tendinopathy, which is an overuse injury caused due to extensor mechanism it complies of a complex structure formed by quadriceps muscle and tendon, the patella and patellar tendon and the ligaments that surround and stabilize the knee (the quadriceps muscles are connected to the inferior pole of the patella by the common quadriceps tendon through a sesamoid bone, the patella.. Key Words: Jumpers knee, Overuse Injury, Knee extensor mechanism, Quaadriceps.

A Novel and Effective Surgical Technique for Reconstruction of Extensor Mechanism with Iliotibial Band Tendon Graft After Patellectomy for Primary Patella Tumor.

Amongst primary patella tumor Campanacci grade 3 tumor of Giant cell tumor of bone (GCTB) and malignant tumors requires patellectomy. We had a patient with huge recurrent GCTB of patella with involvement of skin. We reconstructed extensor mechanism of Knee with long iliotibial band (ITB) tendon graft. After patellectomy, we harvested long ITB graft (length 22cm; width proximally 6cm, distally 1.5cm) through patellectomy wound and small "L" shaped incision proximally. We passed ITB graft from patella tendon and quadriceps tendon in figure of 8 manner and sutured it back to itself and host tendon with fiber Wire and closed both the wounds primarily. We started ROM and quadriceps strengthening in graded manner. We measured functional outcome with Musculoskeletal Tumour Society (MSTS) scoring system. There were no post-operative complications. At 10weeks follow up, patient had no extension lag and knee ROM was 90°. At final follow up of 7months patient regained pre-operative functional status without knee instability. Her MSTS score was 30 and she was disease free. Reconstruction of extensor mechanism of knee with ITB graft doesn't have donor site morbidity and gives excellent function with graded physiotherapy protocol.

A Histological and Biomechanical Analysis of Human Acellular Dermis (HAD) Created Using a Novel Processing and Preservation Technique.

Large and complex defects requiring reconstruction are challenging for orthopaedic surgeons. The use of human acellular dermal (HAD) matrices to augment large soft tissue defects such as those seen in massive rotator cuff tears, knee extensor mechanism failures and neglected Tendo-Achilles tears has proven to be a valuable tool in surgeons reconstructive armamentarium. Different methods for allograft decellularization and preservation alter the native properties of the scaffold. Traditional processing and preservation methods have shown to have drawbacks that preclude its widespread use. Some of the common issues include inferior biomechanical properties, the risk of rejection, limited customization, difficulty in storing and transporting, the requirement of pre-operative preparation, and last but not the least increased cost. We describe a novel processing and preservation method utilizing a two-step non-denaturing decellularization method coupled with preservation using a water-sequestering agent (glycerol) to remove immunogenic components while retaining biomechanical properties. The efficiency of this novel process was compared with the traditional freeze-drying method and verified by histological evaluation and biomechanical strength analysis. The absence of cellular components and matrix integrity in hematoxylin and eosin-stained glycerol-preserved HAD (gly-HAD) samples compared to freeze-dried HAD (FD-HAD) demonstrated effective yet gentle decellularization. Biomechanical strength analysis revealed that gly-HADs are stronger with an ultimate tensile load to the failure strength of 210 N compared to FD-HAD (124N). The gly-HADs were found to have an optimal suture-retention strength of 126 N. Finally, sterility testing of the resultant grafts was checked to ensure a sterility assurance level of 10-6 to establish implantability. The novel processing and preservation technique is described in this paper to create a Human Acellular Dermis with higher biomechanical strength and superior histological characteristics. The processing and preservation technique ensured high sterility assurance levels to establish implantability.

Single-Joint Type Hybrid Assistive Limb for Knee Training in the Acute Postoperative Phase After Opening Wedge High Tibial Osteotomy: A Feasibility and Safety Trial.

Opening wedge high tibial osteotomy (OWHTO) influences the knee extensor mechanism, the range of passive motion of knee extension and persistent quadriceps, and anterior knee pain and weakness. Rehabilitation should focus on quadriceps strength and improving joint mobility. The single-joint hybrid assistive limb device (HAL-SJ) is a wearable exoskeleton cyborg. In this study, we investigated the feasibility and safety of HAL-SJ training after the early postoperative period following OWHTO and whether the use of this device can improve functional outcomes, including knee muscle extensor strength and knee extension range of motion without knee pain. Patients who had been diagnosed with knee osteoarthritis and had undergone OWHTO were assessed for eligibility in this prospective trial conducted at our institution between June 2015 and November 2020. The participants were split into two groups, i.e., 10 patients in the hybrid assistive limb (HAL) group and eight patients in the control group. We initiated HAL-SJ therapy on postoperative day 8 and continued it until the patient's discharge. During the hospitalization period, patients engaged in HAL-SJ-assisted knee extension exercises. This exercise routine encompassed five sets, each comprising 10 repetitions, and was conducted twice a week. We conducted assessments aimed at detecting any potential adverse events that could be linked to HAL training. Assessment of the knee extension angle via the visual analog scale (VAS) and strength assessments using a hand-held dynamometer (HHD) were conducted. To compare clinical outcomes before and after OWHTO, knee extension angle, the VAS, HHD, Japanese Orthopaedics Association (JOA) score, and the Japanese Knee Osteoarthritis Measure (JKOM) were assessed at four distinct time points. No adverse events were observed during the study. The assessment of clinical outcomes before and after OWHTO demonstrated a gradual improvement in outcomes. The single-joint hybrid assistive limb device in patients who underwent OWHTO appears to be potentially safe. It contributed to enhanced muscle activity efficiency by reducing knee pain and improving knee extension angles in the early postoperative phase.

Superolateral Hoffa fat pad edema in adolescent competitive alpine skiers: temporal evolution over 4 years and risk factors

ObjectivesTo longitudinally assess and correlate the prevalence of superolateral Hoffa fat pad (SHFP) edema with changes in features of the knee extensor mechanism in adolescent competitive alpine skiers over 48 months.MethodsCompetitive alpine skiers were prospectively enrolled in 2018 and underwent bilateral knee MRI at baseline and after 48 months. MRI was assessed for the prevalence of SHFP edema. Features of the knee extensor mechanism were assessed by measuring the trochlear sulcus angle and depth, lateral and medial trochlear inclination, trochlear angle, patella tilt, Insall‒Salvati ratio (ISR), and patellar ligament to lateral trochlear facet (PL-T) distance. Separate logistic regression models were used to calculate the odds ratios between each measurement and the presence of SHFP edema at both time points.ResultsSixty-three athletes were included in the study (mean age 15.3 ± 1.3 years, 25 women). At baseline, 23 knees had SHFP edema, increasing to 34 knees at the 48-month follow-up. At baseline, knees with measurements in the highest quartile for ISR and lowest quartile for trochlear depth and PL-T were 9.3, 5.1, and 7.7 times more likely to show SHFP edema, respectively. At follow-up, these correlations were confirmed and additionally, knees with measurements in the highest quartile for trochlear sulcus angle and the lowest quartile for lateral trochlear inclination were 4.1 and 3.4 times more likely to show SHFP edema.ConclusionAn increased prevalence of SHFP edema in competitive alpine skiers during adolescence was associated with persistent high-riding patella, reduced patellar ligament to trochlear distance, and flattened lateral trochlear facet.Critical relevance statementIn clinical routine, assessment of the mechanical properties of the knee extensor mechanism, together with anatomical developments during adolescence, may improve the understanding and management of patellofemoral instability.Key points• Superolateral Hoffa fat pad (SHFP) edema is a frequent cause of anterolateral knee pain but the role of predisposing factors is still debated.• A higher prevalence of SHFP edema was associated with high-riding patella, reduced patellar ligament to trochlear distance, and flattened lateral trochlear facet.• Understanding of the mechanical interaction and the anatomical development of the knee during adolescence provides further insight into the development of SHFP edema.Graphical

Patellar and quadriceps tendon rupture are associated with hip fracture in hemodialysis patients with severe hyperparathyroidism.

Spontaneous rupture of the patellar (PTR) and quadriceps (QTR) tendon is infrequent. Systemic diseases such as diabetes mellitus, CKD, and secondary hyperparathyroidism (SHPT) are risk factors. The present cohort study aimed to evaluate risk factors associated with tendon rupture in hemodialysis (HD) patients with SHPT, as well as outcomes including surgical complications, re-ruptures, and fracture. Baseline clinical, laboratorial data, and radiographs were analyzed. Patients were followed up from March 2012 to March 2020. One-hundred thirty-one patients (≥18yr of age, on HD ≥ 6mo, with SHPT) were included. Incidence rates of PTR and QTR were 2.3 and 1.7/10000 HD patients/yr, respectively. The mean age of patients with tendon rupture was 44.0 ± 11.2yr. These patients exhibited higher serum levels of phosphorus (6.3 ± 1.5mg/dL vs 5.6 ± 1.1mg/dL; P = .005), PTH (2025.7 ± 667.6pg/mL vs 1728.4 ± 684.8pg/mL; P = .035), and C-reactive-protein (35.4 ± 32.9mg/dL vs 17 ± 24.5mg/dL; P = .002) compared to the group without tendon rupture. The mean follow-up was 56.7 ± 27.1mo. No patient required a new surgical approach or experienced re-rupture. Of all patients, 31% experienced hip fracture: 50% in the group with rupture (29.5 ± 17.4mo after the tendon rupture) vs 26% without tendon rupture (P = .015). After adjustment, the hazard ratio for hip fracture was 2.87 (95% CI, 1.27-6.49; P = .012). Patients with SHPT and high levels of phosphorus, PTH, and inflammatory markers were at greater risk for tendon rupture. Surgical complication rates were low. However, results suggest that tendon rupture of knee extensor mechanism in HD patient with SHPT should be regarded as a "red flag" for future hip fracture.

Soft Tissue Reconstruction of the Knee Extensor Mechanism with Free Flaps: A 7-Year Institutional Experience

Soft Tissue Reconstruction of the Knee Extensor Mechanism with Free Flaps: A 7-Year Institutional Experience

Patellar tendon shortening surgery restores the knee extensor mechanism in flexed knee gait in children with cerebral palsy

BackgroundThis study evaluated a patellar tendon shortening (PTS) surgical procedure that uses an overlapping repair combined with an additional Tycron non-absorbable suture to support the shortening in children with Cerebral Palsy (CP). This study aimed to outline this surgical technique and to evaluate its effectiveness in restoring the knee extensor mechanism. MethodsThe sagittal plane lower limb kinematics, peak knee extensor moment, gait deviation index (GDI), localised movement deviation profile (MDP), temporospatial parameters, passive knee extension ROM, quadriceps lag, and knee extensor strength were calculated pre- and postoperatively. To determine significant differences a robust linear regression model with high breakdown point and high efficiency was fitted to the data. ResultsIn this retrospective cohort study, a total of 41 patients with CP who were treated with unilateral or bilateral PTS in isolation or as part of single event multilevel surgery (SEMLS), with a mean age of 11.1 years were included. The knee extension angle improved at initial contact (p < 0.0001), and during stance phase (p < 0.0001). The peak internal knee extensor moment decreased during early (p = 0.0014) and late stance phase (p < 0.0001). The quadriceps lag decreased (p < 0.0001) and knee extensor strength increased (p < 0.0001). The GDI improved (p < 0.0001), as well as the localised MDP for sagittal angles (p < 0.0001) and moments (p = 0.0001). Walking speed (p = 1.0) remained unchanged, but the cadence decreased (p = 0.024) and step length increased (p = 0.0001). ConclusionsThe knee extension angle and moment during stance phase improved significantly. The children with CP in this study showed improvements in knee extensor strength and quadriceps lag. Thereby it can be concluded that the PTS procedure was able to restore the knee extensor mechanism effectively.

Acute traumatic patellar tendon rupture and simultaneous fracture of the tibial tubercle avulsion in a premature soccer player

Bone-tendon junctions are prone for acute trauma due to its structural weakness, especially in premature males. For the lower limb, the most eminent area is the tibial tubercle apophysis. Osgood Schlatter disease (OSD) due to repetitive trauma or epiphyseal fractures due to one trauma is well described in literature and known in pediatric practice. Traumatic distal patella tendon ruptures on the other hand are a typical injury of the knee extensor mechanism of mature patients in the fourth decade. Here, the very rare condition of fracture of the tibial tubercle apophysis with simultaneous rupture of the distal patellar tendon of a 15 year old soccer player with previous history of OSD is presented including a review of the recent literature.

134 Simultaneous Bilateral Patella Tendon Rupture: A Systematic Review

Abstract Aim A single patella tendon rupture is relatively uncommon, but a simultaneous bilateral event is a rare occurrence and has been scarcely reviewed in the literature. This review was carried out to analyse the existing literature on this event, with the aim of proposing a standardised approach to the diagnosis and management of this injury. Method A systematic review was conducted using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Three independent reviewers conducted searches in PubMed, OvidSP for Medline and Embase, as well as Cochrane Library using the same search strategy. From a total of 183 studies, 45 were included, i.e., 90 patellas. Results 46 patellas had a Type 1 Rupture equating to 51%, with Type 3 being the least common, with only 7 patellas sustaining this injury. The mean Insall-Salvio ratio for each knee was 1.62 (R) and 1.60 (L). Direct Primary Repair was the most common surgical technique compared to Tendon Reconstruction, with End to End and Transosseous techniques split almost equally. Brace immobilisation was preferred overcast, with a mean start to weight-bearing of 3.23 weeks post-op. Conclusions Bilateral patellar tendon rupture is a rare injury that should be considered in patients with knee extensor mechanism disruption. The key limitation of this study was the low number of patients encompassed by the eligible literature. There is space for a higher level of evidence study, specifically regarding surgical treatment choice and methods, as well as post-operative management, which could potentially improve the outcomes in the management of this injury.

Osteosynthesis of a patellar fracture with repair of the knee extensor mechanism: Case report

Patella fractures correspond to 1% of all fractures. In recent decades, the role of the patella in increasing the lever arm of the quadriceps has been well defined. Surgical treatment is indicated for open fractures, those that compromise the function of the extensor mechanism, those with a joint gap >5mm and/or joint incongruity >3mm, a group that corresponds to around 30% of the total. Anatomical reduction and stabilization with various types of modified tension bands is the most frequently used procedure. Biomechanical studies have shown that stabilization through the use of a tension band replacing the Kirchner wires with cannulated screws presents adequate resistance to fracture displacement and provides greater stability than the classic configuration, maintaining the theoretical principle of converting the forces of anterior tension of the patella generated by the quadriceps in compression at the level of the articular surface. A case of a patient who required reduction and osteosynthesis of an exposed patella fracture, associated with an extensor mechanism lesion, is presented. Clinical and radiographic characteristics of the patient and the resolution of the case are described.

Knee Extensor Mechanism Complications After Autograft Harvest in ACL Reconstruction: A Systematic Review and Meta-analysis.

Existing systematic reviews have sought to characterize the relative donor-site morbidity of bone-patellar tendon-bone (BTB) and quadriceps tendon (QT) grafts after anterior cruciate ligament reconstruction (ACLR). However, no studies have reported the pooled proportions of patellar fractures and donor tendon ruptures across the body of literature. To estimate the proportion of patellar fractures, patellar tendon ruptures, and QT ruptures associated with BTB or QT autograft harvest during ACLR using published data. Systematic review; Level of evidence, 4. A meta-analysis was conducted according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines using 3 online databases (PubMed, Scopus, and Web of Science). A total of 800 manuscripts were included in the initial research of peer-reviewed articles in English that reported extensor mechanism complications associated with graft harvest in patients after ACLR. Pooled proportions of patellar fractures, patellar tendon ruptures, and QT ruptures were calculated for each graft type (BTB, QT) using a random-effects model for meta-analysis. A total of 28 studies were analyzed. The pooled proportion of patellar fractures was 0.57% (95% CI, 0.34%-0.91%) for the BTB harvest and 2.03% (95% CI, 0.78%-3.89%) for the QT harvest. The proportion of patellar tendon ruptures was 0.22% (95% CI, 0.14%-0.33%) after the BTB harvest, and the proportion of QT ruptures was 0.52% (95% CI, 0.06%-1.91%) after the QT harvest. The majority of included studies (16/28 [57.1%]) had an evidence level of 4. Based on the current literature, the proportion of extensor mechanism complications after ACLR using either a BTB or a QT autograft is low, indicating that the extensor mechanism harvest remains a safe option. A higher proportion of patellar fractures was noted for QT grafts and a higher proportion of donor tendon ruptures was noted for QT grafts compared with BTB grafts.

PATELLA FRACTURES, EPIDEMIOLOGY, ANATOMY, FUNCTION, MECHANISMS OF ACTION, CLASSIFICATION, CLINICAL PRESENTATION, IMAGING PRESENTATION, TREATMENT AND COMPLICATIONS

Introduction: The patella has a great importance in the extension and flexion activities of the knee, being paramount in the patient's quality of life. Nowadays the surgical options that stand out the most are open reduction plus internal fixation and resection of the patella. The patella increases the leverage of the quadriceps. Management following patella injury has been based on preservation of bone and vascular supply, in addition to joint restoration and extensor function. In patella fractures, it is essential to reflect on the biomechanics of the bone and the fixation technique to be used. Objective: to detail the current information related to patella fractures, epidemiology, anatomy, function, mechanisms of action, classification, clinical presentation, imaging presentation, treatment and complications. Methodology: a total of 32 articles were analyzed in this review, including review and original articles, as well as clinical cases, of which 24 bibliographies were used because the other articles were not relevant for this study. The sources of information were PubMed, Google Scholar and Cochrane; the terms used to search for information in Spanish, Portuguese and English were: patella, patellar fractures, knee trauma. Results: Patellar fractures comprise 1% of all fractures in humans, with a 2:1 male to female ratio. They occur more frequently in individuals between 20 and 50 years of age. The frequencies of pseudarthrosis and infection are relatively lower after the surgical procedure. Approximately 2 to 7% of patellar fractures are open fractures. Their classification is descriptive. Conclusions: The patella is the largest sesamoid bone in the human body with several important functions. Frequently, patellar fractures appear after falls on the knee, blows and unexpected and energetic muscular pulls. The diagnosis is made by means of clinical history, physical examination and complementary radiography. Anteroposterior and lateral projections of the knee should be performed. For conservative treatment it is essential that the knee extensor mechanism is intact. There are several methods of surgical treatment, in general the open reduction and internal fixation present good results. Complications include post-traumatic osteoarthritis, alteration or loss of mobility of the knee, refracture, fixation failure, osteonecrosis, intolerance to osteosynthesis material, loss of strength of the extensor mechanism, loss of extension, instability of the patella and pseudoarthrosis. KEY WORDS: patella, knee, fracture, treatment, osteosynthesis.

Knee Extensor Mechanism Complications Following Autograft Harvest In ACL Reconstruction: A Systematic Review and Meta-Analysis

Knee Extensor Mechanism Complications Following Autograft Harvest In ACL Reconstruction: A Systematic Review and Meta-Analysis

Patellar tendon mid-substance tear after total knee arthroplasty: a case report

Extensor mechanism of knee plays important role in successful long term functional outcome after total knee arthroplasty (TKA). Any injury to extensor mechanism during or after surgery can cause functional disability which can be devastating for patients. Patellar tendon injuries are not very common after TKA. The author reported a rare case of patellar tendon mid-substance tear after TKA, which was successfully managed by reconstruction using grafts without any implant.