Locked Knee Research Articles

Assessment of gait stability, harmony, and symmetry in subjects with lower-limb amputation evaluated by trunk accelerations.

Analysis of upper-body accelerations is a promising and simple technique for quantitatively assessing some general features of gait such as stability, harmony, and symmetry. Despite the growing literature on elderly healthy populations and neurological patients, few studies have used accelerometry to investigate these features in subjects with lower-limb amputation. We enrolled four groups of subjects: subjects with transfemoral amputation who walked with a locked knee prosthesis, subjects with transfemoral amputation who walked with an unlocked knee prosthesis, subjects with transtibial amputation, and age-matched nondisabled subjects. We found statistically significant differences for stability (p < 0.001), harmony (p < 0.001), and symmetry (p < 0.001) of walking, with general trends following the noted order of subjects, but with the lowest laterolateral harmony in subjects with transtibial amputation. This study is the first to investigate upper-body acceleration of subjects with unilateral lower-limb amputation during walking who were evaluated upon dismissal from a rehabilitation hospital; it is also the first study to differentiate the sample in terms of level of amputation and type of prosthesis used.

The �Chalky Culprit� of acute locked knee

Acute locked knee is commonly caused by tears of the menisci in the knee, osteochondral injuries and also by the stump of a ruptured anterior cruciate ligament. We present two cases of acute locked knee atypically caused by gouty tophaceous lesions in the knee.

Suspension of Leg via a Single Tibial Pin Provides Postoperative Elevation and Pressure Off-loading for Lower Extremity Free Flaps.

Sir: Postoperative positioning of patients undergoing reconstruction of posterior leg and foot defects remains a significant challenge. Considerations include the necessity to elevate the lower extremity, relieve pressure, perform local wound care, and ensure patient comfort. Many solutions have been proposed in the literature including the maintenance of a prone position and the use of splints with bulky dressings to relieve pressure. In recent years, external fixation has become a popular option. Much of the literature describes modifications of the Hoffman apparatus and other external fixation devices utilizing multiple pins.1–4 We present a method of lower extremity elevation utilizing a single tibial pin outside the zone of injury. A 30-year-old male patient suffered a degloving injury in his heel in an industrial accident. He was initially managed with debridement, replacement of the degloved tissue, and placement of a subatmospheric pressure dressing. During the same operation, a midshaft tibial unicortical pin was placed to facilitate patient management. The pin was placed approximately midshaft through the tibia (Fig. 1), with particular attention paid in balancing the leg. A pin placed too distally will cause a locked knee, and conversely a pin placed too proximally will not provide an adequate elevation and relief from venous congestion.5 The pin was tethered to a bed box frame with an adjustable kerlix gauze (Fig. 2). The leg was then placed in a removable splint to ensure dorsiflexion of the ankle joint. The patient eventually underwent definitive closure with a vastus lateralis free flap. Strict leg elevation using this system was well tolerated by the patient, and he asked to keep the pin for several extra weeks after discharge because of the ease of using it to maneuver and elevate the leg during his rehabilitation.Fig 1: The external fixator pin is placed midshaft through the tibia.Fig 2: The pin is tethered to the bed box frame with adjustable kerlix gauze.As reported in the literature, there are many benefits to suspending the reconstructed leg including eliminating pressure on the reconstruction and decreasing venous congestion through reliable and constant elevation. This method also allowed for easy access during dressing changes and flap checks and required very little manipulation of the leg. We believe that our approach is unique from that of others in that it requires only placement of a single pin, and this pin is outside the zone of injury. Because a removable tether hangs the leg, physical therapists are easily able to remove the leg from suspension and help the patient perform dangling and other exercises. In summary, we recommend that this method of lower extremity suspension be considered in the postoperative management of patients undergoing complex reconstruction of the posterior calf and heel. The tibial traction pin achieves the goals of pressure relief, consistent elevation, improved access for flap monitoring and care, and enhanced patient comfort as exhibited in this case. DISCLOSURE The authors have no financial interest to declare in relation to the content of this article and also to the products, devices, or drugs mentioned in this article. The Article Processing Charge was paid for by the authors. PATIENT CONSENT The patient provided written consent for the use of his image. Sameer M. Kapadia, BS Madeleine J. Gust, MD Mohammed S. Alghoul, MD Gregory A. Dumanian, MD Division of Plastic and Reconstructive Surgery Northwestern University Feinberg School of Medicine Chicago, Ill.

The effect of a knee ankle foot orthosis incorporating an active knee mechanism on gait of a person with poliomyelitis

The aim of this case study was to identify the effect of a powered stance control knee ankle foot orthosis on the kinematics and temporospatial parameters of walking by a person with poliomyelitis when compared to a knee ankle foot orthosis. A knee ankle foot orthosis was initially manufactured by incorporating drop lock knee joints and custom molded ankle foot orthoses and fitted to a person with poliomyelitis. The orthosis was then adapted by adding electrically activated powered knee joints to provide knee extension torque during stance and also flexion torque in swing phase. Lower limb kinematic and kinetic data plus data for temporospatial parameters were acquired from three test walks using each orthosis. Walking speed, step length, and vertical and horizontal displacement of the pelvis decreased when walking with the powered stance control knee ankle foot orthosis compared to the knee ankle foot orthosis. When using the powered stance control knee ankle foot orthosis, the knee flexion achieved during swing and also the overall pattern of walking more closely matched that of normal human walking. The reduced walking speed may have caused the smaller compensatory motions detected when the powered stance control knee ankle foot orthosis was used. The new powered SCKAFO facilitated controlled knee flexion and extension during ambulation for a volunteer poliomyelitis person.

Unusual Cause of Knee Locking

We report a case of partial intrasubstance tear of popliteus tendon as an unusual cause of pseudolocking of the knee. A 13-year-old semiprofessional soccer player applied to our clinic with a locked right knee in spite of the therapy applied (cold pack, NSAID, and immobilization) in another institution 20 days after the injury. Significant extension loss was observed in his right knee with 30°–90° ROM. Magnetic resonance imaging (MRI) and arthroscopy confirmed the intrasubstance tear of popliteus tendon and synovitis. The ruptured part of the tendon was debrided, and the inflammatory tissue around the tendon, which may lead to pseudolocking, was gently removed with a shaver in order to regain the normal ROM. The patient was discharged with full ROM and weight bearing first day after the surgery. To our knowledge, this is the first case demonstrating intrasubstance tear of popliteus tendon causing pseudolocking of the knee.

Successful repair of an isolated osteochondral fracture of the patella presenting with locking of the knee

A 15-year-old boy presented with a locked knee after a football injury. Sudden valgus impact to the planted right leg caused a patellar osteochondral fracture diagnosed by magnetic resonance imaging. The 2.5-cm fragment had avulsed off the medial facet without damage to the medial retinaculum or the medial patellofemoral ligament. The fracture was stabilised with headless compression screws. It had healed at 8 weeks, with the patient being able to bear full weight, and with a full range of active knee movement. At 4 months, he had returned to playing football for his school team.Normally, such a fracture occurs due to sheering force on the patella against the femur during the relocation phase of an acute patellar dislocation. In this case, the patella may have subluxed and then reduced spontaneously, without causing a true dislocation or damage to the medial soft tissue restraints. The energy dissipated at contact with the femur would however be sufficient to sheer the fragment off the patella. We believe this is the first report of successful repair of an osteochondral patellar fracture sustained by this mechanism.

The diagnostic value of the stump impingement reflex sign for determining anterior cruciate ligament stump impingement as a cause of knee locking

BackgroundThe stump impingement reflex is a subtle bounce to the knee thought to be caused by hamstring contraction when the knee is brought into extension and the torn ACL stump impinges between the distal femur and the tibial plateau. We have studied the diagnostic value of this sign.FindingsFrom Feb 2008-Feb 2009, we audited 30 patients who underwent urgent arthroscopy for acutely locked knees. The presence of the stump impingement reflex prior to surgery was compared with the intra-operative findings. The diagnostic values of the stump impingement sign were found to be: Sensitivity 58%, Specificity 81%, Positive predictive value 70%, Negative predictive value 72% and Accuracy 71%.ConclusionsWe believe that the stump impingement reflex is a specific sign for ACL stump impingement as a cause of knee locking. We recommend close inspection for this sign when examining locked knees.

Shelf Syndrome of the Knee in Elderly People: A Report of Three Cases

Shelf syndrome occurs mainly in younger people (particularly athletes) and rarely in elderly people. We report on 3 elderly patients with a medial synovial plica causing severe pain and locked knees. They had had no symptoms in their early or middle life. After removal of the shelf, the symptoms improved considerably. Although shelf syndrome is rare in the elderly, it should be suspected whenever severe pain and a locked knee are present.

Change of signal intensity in the displaced medial meniscus after its reduction on MRI

To compare magnetic resonance (MR) signal intensity in the medial meniscus at the time of displacement and after its reduction in patients with a displaced bucket-handle tear of the meniscus associated with anterior cruciate ligament (ACL) injury. Nine chronic ACL-deficient patients (3 male, 6 female, mean age 29years) with locking due to a displaced fragment of the medial meniscus following a bucket-handle tear were involved in this study. In all patients, the following two-stage surgeries were planned as follows: first operation, arthroscopic reduction of the meniscus; second operation, meniscal repair and ACL reconstruction after immobilization for 1-2weeks. Magnetic resonance imaging (MRI) evaluation using coronal T2*-weighted images was performed when the knee was locked and after the meniscus was reduced. Signal intensity before and after meniscal reduction was compared in the same patients. In 8 of the 9 patients, the displaced fragment exhibited high signal intensity in 1 patient and mildly high in 7 patients. After its reduction, the signal intensity changed to low in all 8 patients. A high-intensity signal in the displaced fragment of the medial meniscus may change to low after its reduction to its original position. Therefore, at the time of decision-making regarding meniscus repair for a displaced meniscus in a locked knee, surgeons should give priority to arthroscopic findings rather than to signal intensity on MRI. Diagnostic study, Level III.

Misdiagnosis of an Atypical Cyclops Lesion 4 Years After Single-bundle Anterior Cruciate Ligament Reconstruction

Development of a cyclops lesion is a well described complication after anterior cruciate ligament (ACL) reconstruction. It commonly results in gradual extension loss during the early postoperative course, and magnetic resonance imaging (MRI) of the soft tissue nodule attached to the ACL graft is needed. Cyclops lesions are easy to diagnose based on the symptoms and MRI findings. Previous study showed that 78.6% of cyclops lesions had extension loss within 6 weeks postoperatively, and the diagnosis of 92.8% cases of cyclops lesions was established within 6 months.This article describes a case of misdiagnosis of a cyclops lesion 4 years after ACL reconstruction as a meniscal lesion combined with a meniscal cyst. The patient was asymptomatic for 4 years and then presented with a locked left knee and pain at the inferior pole of the patella during an attempt to gently extend the knee. Magnetic resonance imaging revealed a lateral meniscal cyst. The knee locking was released suddenly 2 days preoperatively. The authors had attributed the missed diagnosis to an atypical history and symptoms and an associated meniscal cyst.The purpose of this article is to help prevent misdiagnosis of atypical cyclops lesions. Cyclops lesions should be considered in the differential diagnosis of patients who present with gradual or sudden loss of extension after ACL reconstruction, regardless of how much time has passed postoperatively.

4절 연쇄 보조기무릎관절의 개발

본 연구의 목적은 소아마비, 하지 근력약화 등의 장애인이 사용하는 잠금형 보조기무릎관절을 대체하기 위하여, 4절 연쇄 방식의 입각기조절형 보조기무릎관절을 개발하는 것이다. 본 연구에서 개발한 4절 연쇄 보조기무릎관절은 기존의 입각기조절형 보조기무릎관절과 달리, 기하학적으로 잠금상태가 제어되어 전기제어 부품 등이 필요하지 않으며 부피를 최소화하였다. 평가를 위하여, 소아마비로 진단받고 잠금형 보조기무릎관절을 사용해온 소아마비자가 대상자로 참여하였다. 대상자의 걸음걸이를 3차원으로 분석한 결과, 4절 연쇄 보조기무릎관절을 착용했을 때 입각기 동안 무릎관절의 신전이 유지되고 유각기 동안 무릎관절이 굴곡되며 자연스러운 걸음걸이를 보여주었다. This study aims to develop the stance-control typed 4-bar linkage orthotic knee joint that replace the locked orthotic knee joint for the disabled with poliomyelitis and muscle weakness of lower limb. Unlike the existing stance-control orthotic knee joint, there are no needs of electric power, connecting circuit, bulky compomnets, etc, because this 4-bar linkage orthotic knee joint is controled by geometric locking. To evaluate the 4-bar linkage orthotic knee joint, a subject participated in this study who has been diagnosed with lower limb poliomyelitis and have used locked type orthotic knee joint. In the results of analysis of subject's gait using 3-dimentional motion analysis system, this 4-bar linkage orthotic knee joint provide the stability during stance phase and knee flexion during swing phase.

A rare patella anatomical abnormality causing locking in an adolescent girl

Locking is an inability to fully extend the knee and is most commonly associated with meniscal pathology and loose bodies. The locked knee is an infrequent presentation in paediatric orthopaedics, and the presence of a patella protuberance as a cause has never been reported in children or adults. An adolescent female presented with a 4-year history of intermittent locking of the right knee associated with a painful audible 'clunk' on full extension. Plain film radiographs and computed tomography showed a posteriorly projecting bony protuberance over the inferior aspect of the patella. The protuberance was removed via an arthrotomy, and the patient made significant improvement in pain and function with no further locking episodes experienced. IV.

Recurrent locked knee caused by an impaction fracture following inferior patellar dislocation: a case report

IntroductionLocked knee caused by inferior patellar dislocation is considered rare in elderly patients. It was originally thought that, in the osteoarthritic knee, osteophytes on the pole of the patella become entrapped in the inter-condylar notch, which is managed by performing closed reduction and immobilization in a knee splint for three to four weeks. We present an unusual case of a locked knee with an impaction fracture. To the best of our knowledge, there have been no previous reports of such impaction fractures managed with arthroscopy.Case presentationWe present an unusual case of an 88-year-old Caucasian woman with moderate arthritis who had a locked knee caused by an impaction fracture of the patella into the lateral femoral condyle. In this case report, we describe the need for arthroscopic surgery to prevent relocking of the knee in these patients.ConclusionsThis case report emphasizes the need for careful assessment of locked knees in elderly patients. Impaction fractures should be considered in all rare cases of patellar dislocation, and we advocate arthroscopic assessment of the articular cartilage in these patients. This is an important consideration, as the population demographics change and such impaction fractures may become more common in patients with degeneration in the knees.

Inferior Dislocation of Patella after a Total Knee Replacement—A Case Report

Acute inferior dislocation of the patella is rare but has been documented. However, there has been no published report of inferior dislocation of the patella following a total knee replacement (TKR). A 62-year-old man underwent a posterior cruciate retaining TKR Anatomic Graduated Component (AGC) (Biomet, Warsaw, IN) without patellar resurfacing. Perioperative events were unremarkable. The patient presented a year later with an acutely painful locked knee at 60 degrees flexion. Physical examination and radiographs confirmed an inferior dislocation of the patella due to interlocking of superior pole patellar osteophytes on the anterior edge of the intercondylar box of the femoral component. Closed reduction under anesthesia failed and open reduction with debridement of the osteophytes resulted in excellent patellar tracking and a good functional result without any recurrence. Surgeons need to be aware of this rare complication of acute locked knee following TKR which may require open reduction. Also, the debridement of the osteophytes or even a resurfacing of the patella may be a more definitive solution to such patellofemoral problems.

Locked knee from superior dislocation of the patella-diagnosis and management of a rare injury

Knee locking is often caused by a torn meniscus or loose body. A rare cause of knee locking is a superior dislocation of the patella following trauma with less than 20 reported cases in the English literature. An unusual case of a locked knee secondary to interlocking osteophytes between the medial femoral condyle and the inferior pole of the patella without any history of trauma is presented.

Effect of standing posture during whole body vibration training on muscle morphology and function in older adults: A randomised controlled trial

BackgroundWhole body vibration (WBV) is a novel modality of exercise shown to improve musculoskeletal function. This study aims to examine the effects of standing posture during low magnitude WBV training on muscle function and muscle morphology in older adults.MethodsNineteen men and women (50-80 years) were recruited to a three month randomised controlled trial and allocated to one of three groups: WBV with flexed knees (FK), WBV with locked knees (LK), or sham WBV with flexed knees (CON). Exposure was intermittent (1 min WBV:1 min rest) for 20 min, three times per week for 13 weeks. Measurements were taken at baseline and at three months. Primary outcomes included upper and lower body muscle function (strength, power and velocity). Secondary outcomes were muscle morphology, balance, habitual and maximal gait velocity, stair climb power, and chair stand performance.ResultsSixteen subjects completed the study. Relative (%) upper body contraction velocity improved significantly after WBV with FK compared to LK (FK 16.0%, LK -7.6%, CON 4.7, p = 0.01). Relative upper body strength (LK 15.1%, p = 0.02; FK 12.1%, p = 0.04; CON 4.7%) increased significantly following WBV compared to control. Absolute (p = 0.05) and relative (p = 0.03) lower leg strength significantly improved with both standing postures (LK 14.4%; FK 10.7%; CON 1.3%). Only the LK group differed significantly from CON in relative leg strength gains (p = 0.02). Potentially clinically meaningful but statistically non-significant improvements in lower leg muscle cross-sectional area (LK 3.7 cm2, FK 2.4 cm2, CON 2.2 cm2 p = 0.13) were observed after WBV with LK compared to the other groups. No significant effects of WBV on any functional performance tests were observed.ConclusionsOur results suggest that WBV may improve muscle strength and contraction velocity in some muscle groups in older adults. However, hypothesised differential adaptation to standing posture (FK > LK) was observed only for upper body contraction velocity, making recommendations regarding this prescriptive element inconclusive. The efficacy, mechanism of action and long term feasibility of WBV for musculoskeletal health in older adults warrants continued investigation in robustly designed, sufficiently powered future studies.Trial RegistrationACTRN12609000353291.

The Effect of Stance Control Orthoses on Gait Characteristics and Energy Expenditure in Knee-Ankle-Foot Orthosis Users

Stance Control knee-ankle foot orthoses (SCO) differ from their traditional locked knee counterparts by allowing free knee flexion during swing while providing stability during stance. It is widely accepted that free knee flexion during swing normalizes gait and therefore improves walking speed and reduces the energy requirements of walking. Limited research has been carried out to evaluate the benefits of SCOs when compared to locked knee-ankle foot orthoses (KAFOs). The purpose of this study was to evaluate the effectiveness of SCOs used for patients with lower limb pathology. Energy expenditure and walking velocity were measured in 10 subjects using an orthosis incorporating a Horton Stance Control knee joint. A GAITRite walkway was used to measure temporospatial gait characteristics. A Cosmed K4b2 portable metabolic system was used to measure energy expenditure and heart rate during walking. Two conditions were tested: Walking with stance control active (stance control) and walking with the knee joint locked. Ten subjects completed the GAITRite testing; nine subjects completed the Cosmed testing. Walking velocity was significantly increased in the stance control condition (p < 0.001). There was no difference in the energy cost of walking (p = 0.515) or physiological cost index (PCI) (p = 0.093) between conditions. This study supports previous evidence that stance control knee-ankle foot orthoses increase walking velocity compared to locked knee devices. Contrary to expectation, the stance control condition did not decrease energy expenditure during walking.

In brief: meniscal tears.

Meniscal tears can cause considerable symptoms (pain, catching or locking, and effusions) and may subject the knee to premature degeneration of the joint. They also are one of the most common indications for an orthopaedic surgical procedure [3]. As such, although a tear of the meniscus is never life- or limb-threatening, its importance in orthopaedic surgery is undoubted.

Temporal and Spatial Parameters of Crawling in Children With Limb Loss: Implications on Prosthetic Knee Prescription

In Brief Children with limb loss at or above the knee face unique challenges at different stages of development. When transitioning from crawling to walking, and during the intermediate activity of pull-to-stand, a prosthesis must accomplish disparate goals: the mobility necessary for crawling and the stability necessary for standing and walking. This investigation tested the hypothesis that crawling mobility would be reduced when the traditional treatment protocol of a prosthesis lacking an articulating knee joint is followed. Crawling pattern, velocity, and cadence were measured in five children within 3 weeks of the fitting of their first prosthesis, which included an articulating knee. Two conditions were tested: prosthetic knee in its fully articulating state and prosthetic knee locked into extension. In all cases, the locked knee condition reduced velocity and cadence. With one exception, the children exhibited a more typical “step-through” crawling pattern when the knee was unlocked and a less efficient “step-to” pattern when the knee was locked. These data indicate that the traditional prescription protocol for children with transfemoral limb loss may inhibit crawling, which may in turn have long-term implications on motor development. A prosthesis for children with limb loss at or above the knee must accomplish disparate goals when transitioning from crawling to walking: the mobility necessary for crawling and the stability necessary for standing and walking. This investigation tested the hypothesis that crawling mobility would be reduced when the traditional treatment protocol of a prosthesis lacking an articulating knee joint is followed. Two conditions were tested: prosthetic knee in its fully articulating state and prosthetic knee locked into extension. Results indicate that the traditional prescription protocol for children with transfemoral limb loss may inhibit crawling, which may in turn have long-term implications on motor development.

Expanding nail or expanding femur? An adverse event with the expandable intramedullary nail

The expandable intramedullary nail is self-locking and has the advantage of reducing operating time and exposure to ionizing radiation. The nail is recommended for simple diaphyseal fractures involving the middle third of long bones, where the nail can bypass the fracture site by at least 5 cm. We encountered a unique complication with the expandable nail in a simple transverse shaft fracture at the junction of the middle and distal third of the left femur in an otherwise healthy 57-year-old man. The fracture was reduced and a 12-mm expandable nail was inserted. Following full expansion, intraoperative radiographs were obtained prior to closure. After six postoperative weeks, it was noted that the nail expanded the femoral canal, converting a simple fracture to a distally progressing comminuted fracture with a butterfly fragment. A review of the intraoperative radiographs showed slight widening of the medullary canal at the level of the fracture. As the alignment was satisfactory and callus was present, no further surgical intervention was considered. The patient was advised not to bear weight and was provided with a locked knee brace in extension to wear for six weeks. Radiographs at 12 weeks demonstrated good progress of healing with adequate callus and the patient was permitted to bear weight as tolerated and commence knee flexion. The fracture united satisfactorily at four months. This adverse experience emphasizes that caution should be exercised when expanding the nail, with close observation of the medullary canal diameter during the later stages of expansion.