Knee Extensor Mechanism Research Articles

Knee Extensor Mechanism Strength and Its Relationship to Patellofemoral Kinematics in Individuals With Arthrofibrosis Within 6Months After Anterior Cruciate Ligament Reconstruction.

Performance in strength and assessment of patellar tracking is important for patients with arthrofibrosis after anterior cruciate ligament (ACL) reconstruction. The study was to examine the difference of patellofemoral kinematics between the affected and the contralateral limb and to evaluate the relationship between knee extensor strength and patellofemoral kinematics in patients with arthrofibrosis after ACL reconstruction. Cohort study (diagnosis); level of evidence, 3. Laboratory. A prospective cohort of 20 patients with arthrofibrosis after ACL reconstruction was recruited. A total of 20 patients who underwent arthroscopic reconstruction of the double-bundle ACL with a hamstring tendon autograft received standardized patellofemoral kinematics testing and knee extensor strength testing within 6months after primary ACL reconstruction. Computed tomography and dual fluoroscopic imaging were used to evaluate in vivo patellofemoral kinematics of affected and contralateral knees during a lunge task. Knee extensor mechanism strength was measured using a handheld dynamometer. A limb symmetry index of knee strength and patellar mobility was calculated and satisfactory performance defined as ≥90%. There was a statistically significant decrease in the range of patellar inferior shift (P = .020; d = 0.81), flexion (P = .026; d = 0.95), lateral tilt (P = .001; d = 1.04), and lateral rotation (P < .001; d = 0.89) in the affected knee compared with the contralateral knee from 15° to 75° of knee flexion. There was a strong positive linear correlation between knee extensor strength and patellar inferior shift (r = .747; P = .008). A knee extensor strength limb symmetry index <90% was 89% sensitive and 9% specific for limited patellar inferior shift. Patients with arthrofibrosis after ACL reconstruction presented decreased patellar mobility in the arthrofibrotic knee compared with the contralateral knee. The strong correlation between knee extensor strength and patellar inferior shift of the arthrofibrotic knee demonstrates the importance of knee extensor strength in the diagnosis and treatment of patients with knee arthrofibrosis. The knee extensor mechanism strength has high sensitivity but low specificity in identifying a decrease in patellar inferior shift in patients with arthrofibrosis after ACL reconstruction.

Recovery process of the muscle activities during walking with efficient early quadriceps training and gait exercises after total knee arthroplasty

BackgroundTotal knee arthroplasty (TKA) by the trivector approach is less invasive to the knee extensor mechanism; early quadriceps training is possible and a good prognosis is expected after surgery. However, investigations regarding lower limb muscle activity during gait have not been reported after using the trivector approach. To determine an effective postoperative rehabilitation program, we analyzed the recovery processes of leg muscle activities during walking. MethodsFourteen subjects with severe knee osteoarthritis (OA) who underwent early exercises after TKA by trivector approach were included in the TKA group. The control group consisted of eight patients with mild knee OA. Surface electromyography of the vastus medialis (VM), vastus lateralis (VL), and rectus femoris (RF) muscles were recorded and gait speed and step length were measured. The TKA group was measured postoperatively at 3, 12, and 24 weeks. ResultsGait speed of TKA group significantly increased at 12 weeks post-surgery and recovered equal to the control group at 24 weeks. Additionally, step length reached the level of control subjects at 24 weeks. Postoperative activity of VM returned to that of the control group at 12 weeks. VL continued decreasing until 12 weeks compared with the preoperative values, but gradually increased and became equal to the control group at 24 weeks. RF slightly increased at 3 weeks postoperation and remained stable. ConclusionsVM injury by the trivector approach might be small and temporary.Functional recovery of VL was important and early starting rehabilitation program up to 24 weeks is appropriate.

A Strategy for Repair, Augmentation, and Reconstruction of Knee Extensor Mechanism Disruption: A Retrospective Review.

Background:The loss of extensor mechanism continuity that occurs with patellar and quadriceps tendon rupture has devastating consequences on patient function.Purpose:To describe a treatment strategy for extensor mechanism disruption and evaluate the outcomes of 3 techniques: primary repair, repair with semitendinosus tendon autograft augmentation, and reconstruction with Achilles tendon allograft.Study Design:Case series; Level of evidence, 4.Methods:The authors reviewed surgeries for extensor mechanism disruption performed by a single surgeon between 1999 and 2019. Patient characteristics, imaging studies, surgical techniques, and outcomes were recorded. Primary ruptures with robust tissue quality were repaired primarily, and first-time ruptures with significant tendinosis or moderate tissue loss were repaired using quadrupled semitendinosus tendon autograft augmentation. Patients with failed previous extensor mechanism repair or reconstruction and poor tissue quality underwent reconstruction with Achilles tendon allograft. The primary outcome was extensor mechanism integrity at a minimum 1-year follow-up, with extensor mechanism lag defined as >5° loss of terminal, active knee extension. Secondary outcomes included postoperative knee range of motion, International Knee Documentation Committee (IKDC) and Tegner activity scores, and the radiographic Caton-Deschamps Index.Results:Included were 22 patellar tendon and 21 quadriceps tendon surgeries (patients: 82.5% male; mean age, 48.1 years; body mass index, 31). Seventeen (39.5%) cases underwent primary tendon repair, 13 (30.2%) had repair using semitendinosus tendon autograft augmentation, and 13 (30.2%) underwent reconstruction using an Achilles tendon allograft. Seventeen (39.5%) cases had at least 1 prior failed extensor mechanism surgery performed at an outside facility. At the last follow-up, 4 (9.3%) cases had an extensor mechanism lag, no cases required additional extensor mechanism surgery, and all cases were able to achieve >90° of knee flexion. Postoperative IKDC scores were significantly improved with all methods of extensor mechanism surgery, and postoperative Tegner activity scores were significantly improved in patients who underwent primary repair and Achilles tendon allograft reconstruction (P < .05 for all).Conclusion:Primary repair alone, repair using quadrupled semitendinosus tendon autograft augmentation, and reconstruction using Achilles tendon allograft were all effective methods to restore extensor mechanism and knee function with the proper indications. Persistent knee extensor lag was more common in chronic extensor mechanism injuries after failed surgery, although patients still reported significantly improved postoperative functional outcomes.

Quadriceps Tendon Repair Using Double-Row Suture Anchor Fixation

Quadriceps tendon ruptures compromise the knee extensor mechanism and cause an inability to ambulate and significant functional limitations. Therefore, the vast majority of quadriceps tendon ruptures are indicated for operative intervention to restore patient mobility and function. Although these injuries were traditionally repaired using a transosseous repair technique, recent literature has shown that suture anchor repair may offer biomechanical advantages. Additionally, research in other areas of orthopaedics has found that a double-row suture anchor construct can offer additional biomechanical strength to tendinous repair. This technical note describes a safe and effective quadriceps tendon repair using a double-row suture anchor construct.

Synthetic Mesh Reconstruction of Chronic, Native Quadriceps Tendon Disruptions following Failed Primary Repair

Case Two patients presented with chronic knee extensor mechanism disruption after failed primary repairs. Both patients had minimal ambulatory knee function prior to surgical intervention and were treated with a synthetic mesh reconstruction of their extensor mechanism. Our technique has been modified from previously described techniques used in revision knee arthroplasty. At the one-year follow-up, both patients had improvement in their active range of motion and had returned to their previous activity. Conclusion Synthetic mesh reconstruction of chronic extensor mechanism disruption is a viable technique that can be utilized as salvage for the persistently dysfunctional native knee.

Pedicled fibular transfer for biologic knee extensor tendon reinsertion following proximal tibial resection in pediatric osteosarcoma: Long-term outcomes.

Proximal tibial sarcoma resections result in a reconstructive challenge, necessitating joint and extensor mechanism reconstruction. The gait and functional outcomes for children reconstructed with a combination of megaprosthesis and pedicled fibular flap for extensor mechanism reconstruction, are presented. Four patients, aged 11-18 years old, were available for comprehensive analysis. The proximal tibial osteosarcoma was resected, and the reconstructive technique involved a megaprosthesis for the knee joint, used in combination with a pedicled fibula flap as a biologic structure for reinsertion of the knee extensor mechanism. Outcomes were measured with three-dimensional gait analysis and patient questionnaires. Minor postoperative wound issues occurred in some patients, requiring debridement with skin grafting. One patient fractured their transferred fibula, requiring fixation. The follow up period ranged from 1.7 to 24 years postoperatively. The longevity and quality of reconstructions were strong, measured by both objective and patient-reported outcomes. All patients reported independent walking >500m in the Functional Mobility Scale and rated their walking as a nine or 10 (out of 10) on the Functional Assessment Questionnaire. Knee society scoring revealed overall satisfaction rate of 75-80%. No patients required gait aids. The gait profile analysis revealed effective gait patterns, with patterns deviating 5.4-7° from "typical gait." Deviations >6.5° are considered abnormal. The long-term results of combining a megaprosthesis with a pedicled fibula flap for extensor reinsertion, revealed a high level of independent function. The patients performed well, without the need for aids, and gait study evidence of minimal gait deviations.

Chronic Quadriceps Tendon Rupture Reconstruction with Sartorius Muscle Transfer: A Report of Five Cases.

Summary:Disruption of the knee extensor mechanism is an unfavorable situation because efficient mobilization requires a functioning knee extensor apparatus. The purpose of this retrospective study was to report our technique of sartorius muscle transfer for restoration of extension mechanism function and the outcomes of five patients. Patients with ruptured knee extensor mechanism secondary to trauma or knee arthroplasty-related issues were studied retrospectively. In all patients, sartorius muscle was transferred to restore the quadriceps tension deficit. Increase in the knee active range of motion, increase in the extensor mechanism power by one grade on Medical Research Council scale, and improvement in the extension lag were observed in all patients. The sartorius muscle transfer can be a reliable option to restore the knee extensor mechanism in chronic quadriceps tendon injuries. Our initial results are promising and showed improvement of the extensor mechanism muscle power, increased knee active range of motion, and decreased knee extension lag. The complications we observed did not impair the successful outcome of the sartorius transfer and were anticipated given the complexity of the studied cases. We encourage additional studies of sartorius muscle transfer to treat chronic quadriceps tendon injuries.

Considerations in spontaneous quadriceps tendon rupture repair in end-stage renal disease patients: A case report

IntroductionSpontaneous quadriceps tendon rupture (SQTR) is a rare injury to the knee extensor mechanism that is usually associated with systemic diseases such as end stage renal diseases (ESRD) and it is more prevalent in the elderly. Due to the underlying pathology, quadriceps tendon rupture warrants special considerations and management in its repair.Case reportWe present two cases of quadriceps tendon rupture in end-stage renal disease (ESRD) patients. The first case; a 57 years old female who had bilateral SQTR and is undergoing hemodialysis. The second patient, a 26 years old male had unilateral quadriceps tendon rupture caused by minimal trauma.The first patient had a trans-osseous repair by direct suturing the quadriceps tendon stump to the proximal pole patella. The second patient was repaired with a modified Bunnel suture and anchor placement on the proximal pole patella. The first case had a re-rupture of the right quadriceps tendon and the second case has recovered with improved outcomes.DiscussionSpontaneous quadriceps tendon rupture is usually underlined by degenerative changes of the tendons. Special care is needed to address the pathologic tendon underlying SQTR. The current surgical literature still lacks the statistical data that shows which surgical approach is most optimal for SQTR in ESRD patients.ConclusionSQTR rupture is generally an injury of brittle tendons caused by underlying diseases. A multidisciplinary and comprehensive approach including a proper surgical approach and postoperative managements are crucial for good functional outcomes of the extensor mechanism.

Knee extension moment arm variations relate to mechanical function in walking and running.

The patellofemoral joint plays a crucial mechanical role during walking and running. It increases the knee extensor mechanism's moment arm and reduces the knee extension muscle forces required to generate the extension moment that supports body weight, prevents knee buckling and propels the centre of mass. However, the mechanical implications of moment arm variation caused by patellofemoral and tibiofemoral motion remain unclear. We used a data-driven musculoskeletal model with a 12-degree-of-freedom knee to simulate the knee extension moment arm during walking and running. Using a geometric method to calculate the moment arm, we found smaller moment arms during running than during walking in the swing phase. Overall, knee flexion causes differences between running and walking moment arms as increased flexion causes a posterior shift in the tibiofemoral rotation axis and patella articulation with the distal femur. Moment arms were also affected by knee motion direction and best predicted by separating by direction instead of across the entire gait cycle. Furthermore, we found high inter-subject variation in the moment arm that was largely explained by out-of-plane motion. Our results are consistent with the concept that shorter moment arms increase the effective mechanical advantage of the knee and may contribute to increased running velocity.

Iliotibial Band Autograft Provides the Fastest Recovery of Knee Extensor Mechanism Function in Pediatric Anterior Cruciate Ligament Reconstruction.

Iliotibial band autograft is an increasingly popular option for pediatric anterior cruciate ligament reconstruction (ACLR). The purpose of this study was to compare recovery of knee extensor mechanism function among pediatric patients who underwent ACLR using iliotibial band (IT), hamstring tendon (HT), quadriceps tendon (QT), and patellar tendon (PT) autografts. One hundred forty-five pediatric athletes (76 female; age 15.0, range 7–21 years) with recent (3–18 months) unilateral ACLR performed drop-jump landing and 45° cutting with 3D motion capture. Knee extensor mechanism function (maximum knee flexion angle, maximum internal knee extensor moment, energy absorption at knee) during the loading phase (foot contact to peak knee flexion) was compared among graft types (20 IT, 29 HT, 39 QT, 57 PT) and sides (ACLR or contralateral) using linear mixed models with sex, age, and time since surgery as covariates. Overall, knee flexion was significantly lower on the operated vs. contralateral side for HT, QT, and PT during both tasks (p < 0.03). All graft types exhibited lower knee extensor moments and energy absorption on the operated side during both movements (p ≤ 0.001). Kinetic asymmetry was significantly lower for IT compared with QT and PT during both movements (p ≤ 0.005), and similar patterns were observed for HT vs. QT and PT (p ≤ 0.07). Asymmetry was similar between IT and HT and between QT and PT. This study found that knee extensor mechanism function recovers fastest in pediatric ACLR patients with IT autografts, followed by HT, in comparison to QT and PT, suggesting that IT is a viable option for returning young athletes to play after ACLR.

Variation in the patellar tendon moment arm identified with an improved measurement framework.

The mechanical advantage of the knee extensor mechanism depends heavily on the patellar tendon moment arm (PTMA). Understanding which factors contribute to its variation may help improve functional outcomes following arthroplasty. This study optimized PTMA measurement, allowing us to quantify the contribution of different variables. The PTMA was calculated about the instantaneous helical axis of tibiofemoral rotation from optical tracked kinematics. A fabricated knee model facilitated calculation optimization, comparing four data smoothing techniques (raw, Butterworth filtering, generalized cross-validated cubic spline-interpolation and combined filtering/interpolation). The PTMA was then measured for 24 fresh-frozen cadaveric knees, under physiologically based loading and extension rates. Combined filtering/interpolation enabled sub-mm PTMA calculation accuracy throughout the range of motion (root-mean-squared error 0.2 mm, max error 0.4 mm), whereas large errors were measured for raw, filtered-only and interpolated-only techniques at terminal flexion/extension. Before scaling, the mean PTMA was 46 mm; PTMA magnitude was consistently larger in males (mean differences: 5 to 10 mm, p < .05) and was strongly related to knee size: larger knees have a larger PTMA. However, while scaling eliminated sex differences in PTMA magnitude, the peak PTMA occurred closer to terminal extension in females (female 15°, male 29°, p = .01). Knee size accounted for two-thirds of the variation in PTMA magnitude, but not the flexion angle where peak PTMA occurred. This substantial variation in angle of peak PTMA has implications for the design of musculoskeletal models and morphotype-specific arthroplasty. The developed calculation framework is applicable both in vivo and vitro for accurate PTMA measurement.

EFFECT OF AUTOGRAFT TYPE ON RECOVERY OF KNEE EXTENSOR MECHANISM FUNCTION FOLLOWING ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION

Background:While multiple studies have shown clear benefits of autograft over allograft for anterior cruciate ligament reconstruction (ACLR) in young athletes, disagreement remains regarding the optimal autograft choice. Recovery from ACLR may be influenced by autograft type, which can include iliotibial band (IT), hamstring tendon (HT), quadriceps tendon (QT), or patellar tendon (PT) depending on skeletal maturity and surgeon preference.Hypothesis/Purpose:This study compared knee joint function among pediatric athletes with different types of ACLR autografts. We hypothesized that knee extensor function would recover faster for graft types that did not disrupt the knee extensor mechanism (i.e., IT and HT vs. PT and QT).Methods:This retrospective study examined 138 pediatric athletes (73 female; mean age 15.5, SD 2.2, range 8-21 years) who had undergone sports biomechanical testing in our motion analysis laboratory following recent unilateral ACLR (mean 7.7, range 3-18 months post-surgery). All reconstructions used autografts including 20 IT, 26 HT, 37 QT, and 55 PT. Lower extremity sagittal plane kinematics and kinetics were measured during vertical drop jump landing (41 cm height) and 45° cutting. Maximum knee flexion angles, internal knee extensor moments, and energy absorption during the landing phase (initial contact to peak knee flexion) of each movement were compared among graft types and sides (ACLR vs. contralateral) using linear mixed models with sex, age, and time since surgery as covariates.Results:Knee flexion was significantly lower on the operated vs. contralateral side for HT, QT, and PT during drop jump and for QT and PT during cutting (p<0.001). All graft types exhibited lower knee extensor moments and energy absorption on the operated side (p<0.05). This asymmetry was most pronounced for QT and PT and least pronounced for IT (Figure 1.1). Loading on the operated limb decreased from IT to HT to QT and PT, while loading on the contralateral limb increased similarly. Asymmetry of kinetics was significantly lower for IT compared with both QT and PT during both movements (p<0.01). Similar patterns were observed for HT but were not always statistically significant. No differences in asymmetry were observed between IT and HT or between QT and PT.Conclusion:Young athletes with IT and HT autografts exhibit greater engagement of the knee extensors during dynamic loading than peers with PT or QT autografts in the 18 months following ACLR. This may be due to extensor mechanism donor site morbidity associated with PT and QT grafts.Tables/Figures:Figure 1.1:.Comparison of operated (red) and contralateral (blue) limbs by graft type (model predicted average and 95% confidence interval)

Gait outcomes following proximal tibial tumor resection and endoprosthetic reconstruction.

Despite the proximal tibia being a common site of primary malignant bone tumors, there is limited information about gait function following proximal tibial tumor resection and endoprosthetic reconstruction (PTR). What is the impact of PTR on gait and quality of life? This was a cross-sectional study of patients ≥18 years old who were ≥2 years post-PTR compared to a control group of similar age and sex distribution. Eighteen participants (9 PTR, 9 Control) were recruited. Gait spatial-temporal data, joint kinematics and kinetics were collected at preferred and fast walking speeds. Community walking cadence, health-related quality of life (SF-36) and knee joint torque were assessed. Comparisons were performed using one-way ANOVAs with Bonferroni corrections for multiple comparisons. Nonparametric tests were used for data not normally distributed. Mean age was 31 years for each group (PTR range = 18-42 yrs, Control range = 18-44 yrs). Compared to both control and nonsurgical limbs, the surgical limb exhibited significantly decreased % single limb support time, reduced heel rise during terminal stance and an absence of normally occurring knee flexion angles, extensor moments and power generation during initial double limb support. Additionally, a reduced peak plantar flexor moment was found for the surgical as compared to the control limb. The number of gait abnormalities increased during fast walking. Significantly reduced surgical knee extensor torque on isokinetic testing and weakness of the knee and ankle on clinical examination support gait findings. During community walking, the number of low frequency strides was an average of 5.3 % greater for the PTR group (p < 0.05). Norm-based PTR group SF-36 component scores were within normal values (53.4 physical, 56.5 mental). Gait abnormalities were consistent with ankle muscle resection and transposition and knee extensor mechanism disruption. Despite these deficits, walking speed and quality of life were relatively normal.

Epidemiology of Acute Extensor Mechanism Injuries in Collegiate-Level Athletes in the United States.

Extensor mechanism injuries involving the quadriceps tendon, patella, or patellar tendon can be a devastating setback for athletes. Despite the potential severity and relative frequency with which these injuries occur, large-scale epidemiological data on collegiate-level athletes are lacking. Descriptive epidemiology study. Level 4. Knee extensor mechanism injuries across 16 sports among National Collegiate Athletic Association (NCAA) men and women during the 2004-2005 to 2013-2014 academic years were analyzed using the NCAA Injury Surveillance Program (NCAA-ISP). Extensor mechanism injuries per 100,000 athlete-exposures (AEs), operative rate, annual injury and reinjury rates, in-season status (pre-/regular/postseason), and time lost were compiled and calculated. A total of 11,778,265 AEs were identified and included in the study. Overall, 1,748 extensor mechanism injuries were identified, with an injury rate (IR) of 14.84 (per 100,000 AEs). N = 114 (6.5%) injuries were classified as severe injuries with a relatively higher median time loss (44 days) and operative risk (18.42%). Male athletes had higher risk of season-ending injuries in both all (3.20% vs 0.89%, P < 0.01) and severe (41.54% vs 16.33%, P < 0.01) extensor mechanism injuries. Similarly, contact injuries were more frequently season-ending injuries (4.44% vs 1.69%, P = 0.01). Women's soccer (IR = 2.59), women's field hockey (IR = 2.15), and women's cross country (IR = 2.14) were the sports with the highest rate of severe extensor mechanism injuries. Extensor mechanism injuries in collegiate athletes represent a significant set of injuries both in terms of volume and potentially to their athletic careers. Male athletes and contact injuries appear to have a greater risk of severe injuries. Injuries defined as severe had a higher risk of operative intervention and greater amount of missed playing time. Knowledge of the epidemiology of extensor mechanism injuries may help clinicians guide their athlete patients in sports-related injury prevention and management.

Patellar Fracture Fixation With Cannulated Compression Screws and FiberTape Cerclage

Transverse patella fractures with loss of knee extensor mechanism function are a common orthopaedic injury requiring operative fixation. Current accepted surgical options for noncomminuted transverse fractures include open reduction with tension band wiring. Although these procedures result in good clinical outcomes and fracture healing, symptomatic hardware from the historically used metal implants is very common. The purpose of this Technical Note is to describe a technique for treatment of transverse patellar fractures using cannulated compression screws with tensioned high-resistance suture tape functioning as the tension band. This technique provides effective, reproducible fracture fixation while minimizing symptomatic hardware, failure, and reoperation.

Moment arm of the knee-extensor mechanism measured in vivo across a range of daily activities

We measured the moment arm of the knee-extensor mechanism as ten healthy young individuals performed six functional activities: level walking, downhill walking, stair ascent, stair descent, open-chain (non-weight-bearing) knee flexion, and open-chain knee extension. The moment arm of the knee-extensor mechanism was described by the moment arm of the patellar-tendon force, which acts to rotate the tibia about the instantaneous axis of rotation (screw axis) of the knee. A mobile biplane X-ray imaging system enabled simultaneous measurements of the three-dimensional movements of the femur, tibia and patella during each activity, from which the position and orientation of the screw axis and the patellar-tendon moment arm (PTMA) were determined. Mean PTMA across all activities and all participants remained nearly constant (~46 mm) from 0° to 70° of knee flexion and decreased by no more than 20% at higher flexion angles. The magnitude of the PTMA varied more substantially across individuals than across activities, indicating that the moment arm is more heavily influenced by differences in knee-joint geometry than muscle loading. Hence, PTMA measurements obtained for a given activity performed by one individual may be used with good confidence to describe the PTMA for any other activity performed by the same individual. Caution is advised when using PTMA measurements obtained from one individual to describe the moment arm in another individual even once the data are normalized by knee bone size, as the PTMA varied by as much as 13% from the mean across individuals.

Plethora of Traumatic Lesions of Bilateral Knee Extensor Mechanism in Osteogenesis Imperfecta

IntroductionInjuries to the quadriceps extensor mechanism are rare in patients with Osteogenesis Imperfecta (OI). To the best of our knowledge, non-union of the patella in OI, either as an isolated problem or in combination with an acute fracture, has not been previously reported.Case reportWe describe how we surgically approached both the fracture and the non-union simultaneously. The surgical technique and steps are described in detail. Post-operative course was uneventful and the outcome was favorable, with full return of function for the patient.ConclusionA review of various knee extensor mechanism injuries in OI is described as illustrated in a single patient. The unusual simultaneous surgical treatment of a non-union and an acute fracture in the same patella shows that despite the severely compromised bone in this rare bone disease the bone still has a capacity to heal with a functional outcome.

Fracture patella: Fixation with cancellous screws and anterior cerclage wiring

Patella is the largest sesamoid bone. It is a triangular bone that lies within quadriceps tendon. Fractures of patella constitute approximately 1% of all skeletal injuries and occur in all age groups. There is always a need to salvage the fracture as it is an important functional structure in extensor mechanism of knee. Its report to evaluate the effectiveness and safety of anterior cerclage wire/tension band wiring technique using two or more cannulated cancellous screws in patients with transverse or transverse with comminuted patellar fractures. Material and Methods: This is a prospective study of 28 patients with transverse or transverse with comminuted fractures. All patients were treated with open reduction and internal fixation using multiple cancellous screws (more than two) and 18G stainless steel wire except two cases with TBW with k wire as per tension band principle. Result-There were 28 patients, 24(85.71%) males and 4(14.28%) females. The age group ranged from 22-60 years with mean age 38 years. The mode of injury was either direct or indirect trauma, fall (74%) followed by RTA (18%) and violent quadriceps contraction (8%). Transverse fractures were present in 60% patients and transverse fracture with comminution in 40% patients. Mean time to achieve union was 10.7 weeks (Range 8-12 weeks). Cases were followed up for 3 months, then at 6 months, thereafter 6 monthly and assessed for recovery of knee function. Study continued up to 12 months to 18 months. Mean ROM at the end of 3 months was 113.8° (90-130) and at final follow up this movement improved up to 125.4° (ROM 100-150). There was loss of reduction in one case, one case of infection and one case of nonunion. No case of implant failure was observed. The study was conducted in Department of Orthopaedics, Hi Tech Medical College, Rourkela and SB Medical College, Hazaribag. The results were graded according to the criteria given by Gaur et al. IJO May 1997. Conclusion: The criteria for surgery, open reduction and internal fixation with multiple cannulated cancellous screws with anterior cerclage was if ˃ 3mm displacement and ˃ 2mm articular step off was present. The screws provide rotation control of fragment and anchorage of cerclage wire. It provides additional compression across the fracture site. Open reduction and internal fixation with cannulated cancellous screws with anterior cerclage /TBW is a safe, reliable and reproducible method in the management of transverse or transverse with comminuted fractures, with less chances of implant failure and less soft tissue irritation.

Judet's quadricepsplasty after total hip arthroplasty and Thompson's quadricepsplasty: A case report

Judet quadricepsplasty provides a gradual release of knee extension contracture occurring due to intrinsic and extrinsic reasons. We herein present a 68-year-old male patient with a fragmented right femur AO (arbeitsgemeinschaft für osteosynthesefragen) Type A3 fracture, which occurred because of an in-vehicle traffic accident 30 years ago. The fracture was fixed with an anterior plate-screw with open reduction, and knee extension contracture had developed after the operation. The distinctive features of this case include a previous, unsuccessful, ipsilateral V-Y quadricepsplasty, an ipsilateral total hip arthroplasty with anterior approach six months ago and a persistent extension contracture for over 30 years. Gradual releasing techniques, as described by Judet, were performed under general anesthesia and sterile conditions with the patient in supine position. Intraoperatively, two displaced screws were detected on the anterior femur, which had adhered to the vastus medialis muscle, and fibrosed. Adhesions were dissected and screws were removed. Before the release of the proximal adhesion of the rectus muscle, a forced external rotation of hip joint was performed to assure that adequate fibrotic tissue had formed on the anterior facet of the joint capsule to prevent anterior instability. Five recurrent knee joint effusions developed after surgery, which were aspirated by needle. Joint fluids were clear and there were no reproductions of any microorganisms. By the end of an uneventful, two-year follow-up period, final knee range of motion was 0-90 degrees. Loss of extension and extensor muscle power had entirely improved by 6 months. In a patient with hip prosthesis, provided that adequate fibrosis has formed on the anterior facet of the joint capsule, rectus release may not cause instability. In cases resistant to rehabilitation, if there is implant, fibrosis or hypertrophic callus which may cause irritation at any level of the knee extensor mechanism, we suggest their resection for a more even anterior cortex contour.

Patellofemoral kinematics in healthy older adults during gait activities.

The patellofemoral (PF) joint is susceptible to many pathologies resulting from acute injury, chronic disease and complications following surgical treatment of the knee. The objectives of this study were to describe case series measurements of patellar motion in healthy older adults as they performed three gait activities, determine patellar tendon angle and moment arm, and show if these quantities were activity dependent. A stereo radiography system was utilized to obtain the 3D PF kinematics of seventeen healthy people over 55years of age (8F/9M, 66±7.9years old, 75.7±20.5kg) as they performed level walking, a step down, and a pivot turn. For a similar portion of the gait cycle, patellar flexion (6.2°±5.8) and average range of motion (ROM) (11.0°±5.9°) for walking with a step down was greater compared to the other gait activities (gait ROM 6.9°±4.3°, pivot ROM 5.7°±3.3°), while the average range of motion for patella tilt was greater during walking with a pivot turn (8.6°±3.9°). However, each subject displayed distinct PF kinematic trends during all activities with a few notable exceptions. Importantly, the knee extensor mechanism characteristics of patellar tendon angle and moment arm showed considerable variation across subjects but were largely unaltered by changing activities. The variation between subjects and the different behavior of the patella during the step down and pivot emphasized the need for analysis of a range of activities to reveal individual response to pathology and treatment in patellar maltracking and osteoarthritis.