Variations in varus/valgus and internal/external rotational knee laxity and stiffness across the menstrual cycle

Cyclic variations in genu recurvatum (GR), general joint laxity (GJL), varus–valgus (VV), and internal–external (IER) rotational laxities and stiffnesses were examined in 64 females and 43 males at two time points during the females' menstrual cycle [days of minimum (T1) and maximum (T2) anterior knee laxity (AKL)]. Cyclic increases in AKL (9.5%), GR (37.5%), and GJL (13.6%) were observed in females but not males from T1 to T2 (p < 0.001). Cyclic increases in VV and IER laxity were negligible (1.5–3.2%, p > 0.320). Females compared to males had lower overall VV stiffness at T2 (F 37% <M) vs. T1 (F 26.9% <M; p = 0.011), but no difference across time points for IER stiffness (p = 0.452). Across both time points, females had consistently greater VV (30.2%) and IER (20%) laxity and less VV (32.5%) and IER (24.3%) incremental stiffness (p < 0.001). Low‐to‐moderate associations were observed between AKL, GR, and GJL with VV and IER laxities and stiffnesses in females as measured at T1 and the change in values from T1 to T2. Whether these findings reflect ligament‐specific responses to hormone changes, or implicate changes in injury risk potential across the menstrual cycle requires further study. © 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 29:318–325, 2011     

Effect of posterior tibial slope on knee biomechanics during functional activity

Treatment of medial compartment knee osteoarthritis with high tibial osteotomy can produce an unintended change in the slope of the tibial plateau in the sagittal plane. The effect of changing posterior tibial slope (PTS) on cruciate ligament forces has not been quantified for knee loading in activities of daily living. The purpose of this study was to determine how changes in PTS affect tibial shear force, anterior tibial translation (ATT), and knee‐ligament loading during daily physical activity. We hypothesized that tibial shear force, ATT, and ACL force all increase as PTS increases. A previously validated computer model was used to calculate ATT, tibial shear force, and cruciate‐ligament forces for the normal knee during three common load‐bearing tasks: standing, squatting, and walking. The model calculations were repeated with PTS altered in 1° increments up to a maximum change in tibial slope of 10°. Tibial shear force and ATT increased as PTS was increased. For standing and walking, ACL force increased as tibial slope was increased; for squatting, PCL force decreased as tibial slope was increased. The effect of changing PTS on ACL force was greatest for walking. The true effect of changing tibial slope on knee‐joint biomechanics may only be evident under physiologic loading conditions which include muscle forces. © 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 29:223–231, 2011     

膝关节镜下膝后侧腔室联合手术入路的探讨

[目的]探讨在关节镜下膝关节后侧腔室联合手术入路的重要性和可操作性。[方法]经过前内侧、前外侧和股骨髁切迹以及后内侧、后外侧和后纵隔内切口联合入路分别入镜、入器械，进行膝关节后侧腔室的探查和手术操作。[结果]216例（239膝）应用联合入路探查和治疗，其中5例膝因关节僵硬操作失败；175例膝用于治疗后侧腔室疾病，膝关节后侧腔室手术视野显著改善，探查和手术操作完善，均达到手术目的。1例膝内侧隐神经不全损伤，没有腘后神经、腓总神经、腘后血管、交叉韧带等重要组织损伤。[结论]膝关节后侧腔室病变较多，是检查和治疗的重要部位，并非“技术盲区”。这种联合手术入路，手术风险低，具备可操作性，可以提高手术效率和质量，可作为膝关节镜下常规手术入路。     

Common knee injuries,diagnosis and management

The knee is a frequently injured joint, and the incidence of injury is increasing. Young adults are most likely to injure their knee through sports participation, and this can result in long-term debility without appropriate early and deferred management. A detailed history and clinical examination, supplemented with radiographic evaluation of the joint and magnetic resonance imaging, assist in the diagnosis and can guide acute and definitive management. Early clinical assessment by an appropriately trained clinician is recommended. Fractures should be managed through orthopaedic trauma services, and soft tissue injuries are often best triaged into specialist acute knee clinics. Early management includes the use of plaster casts, splints or braces according to the injury pattern, and the principles or rest, ice, compression and elevation are followed. Early functional motion should be instituted when safe to do so to prevent arthrofibrosis and secondary complications. Fractures, including osteochondral lesions are typically best dealt with acutely, along with disruptions of the extensor mechanism and displaced meniscal tears causing locking. Non-acute surgical management of other soft tissue injuries is generally preferred, allowing the joint to recover before additional operative insult. Appropriate early intervention by specialist knee services is associated with improved long-term outcomes.     

Fresh osteochondral allografts for advanced giant cell tumors at the knee

Sixteen patients with advanced giant cell tumors presenting at the knee were treated with complete tumor resection and reconstruction using fresh osteochondral allografts. All patients had one or more of the following indications for tumor resection (as opposed to curettage): tumor recurrence, pathologic fracture, or destruction of the subchondral bone plate. At the 3–15-year follow-up period (mean, 9 years), two grafts have been revised to second fresh grafts because of fracture and one graft has been converted to an allograft-implant composite reconstruction. One joint was fused because of late infection. Functional assessment was carried out in 13 patients, and 8 were good or excellent, 4 were fair, and 1 was poor. The authors conclude that the fresh osteochondral allograft is a viabie treatment alternative to prosthetic arthroplasty in advanced, benign, aggressive bone tumors.     

Technical Note A New Arthroscopic Method for Reconstructing the Anterior and Posterior Cruciate Ligaments Using a Single-Incision Technique: Simultaneous Grafting of the Autogenous Semitendinosus and Patellar Tendons

Summary: We established a simultaneous reconstruction method for ruptured anterior and posterior cruciate ligaments (ACL, PCL) using a single-incision technique. Residual PCL was used to determine the position of bone tunnel for ACL reconstruction. The bone tunnel position on the tibia for PCL reconstruction was arthroscopically confirmed by conducting through debridement from the posteromedial portal. Reconstruction substitutes were patellar-tendon bone-tendon-bone for ACL, and semitendinosus tendon for PCL. In the fixation procedure, the PCL substitute was fixed using the Endobutton (Smith & Nephew, Andover, MA) and a ceramic button, and the ACL substitute was fixed with an interference screw. During the surgery, radiographic monitoring and the PCL guide system were not required.Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 15, No 8 (November), 1999: pp 871–876     

Longitudinal changes in knee gait mechanics between 2 and 8 years after anterior cruciate ligament reconstruction

The purpose of this study was to longitudinally investigate changes in knee joint kinematics and kinetics from 2 to 8 years post‐ACLR. Seventeen subjects with primary unilateral transtibial ACLR performed bilateral gait analysis approximately 2 years and 8 years post‐ACLR. Seventeen matched healthy control subjects were also analyzed. Kinematic and kinetic comparisons between the ACLR and contralateral limbs over time were completed using a 2 × 2 (time, limb) repeated‐measures ANOVA. Unpaired Student's t‐tests were used to compare the ACLR and contralateral kinematics and kinetics to the control group. The ACLR and contralateral limbs had similar gait changes over time. Kinetic changes over time included a reduction in first (p = 0.048) and second (p < 0.001) peak extension moments, internal rotation moment (p < 0.001), adduction moment (first peak: p = 0.002, second peak: p = 0.009, impulse: p = 0.004) and an increase in peak knee flexion moment (p = 0.002). Kinematic changes over time included increases in peak knee flexion angle in the first half of stance (p = 0.026), minimum knee flexion angle in the second half of stance (p < 0.001), and average external rotation angle during stance (p = 0.007), and a reduction in average anterior femoral displacement during stance (p = 0.006). Comparison to healthy controls demonstrated improvement in some gait metrics over time. The results demonstrated longitudinal changes from 2 to 8 years after ACLR in knee joint kinetics and kinematics that have been related to clinical outcome after ACLR and the progression of knee OA, and support future larger and comprehensive investigations into long‐term changes in joint mechanics in the ACLR population. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1478–1486, 2018.

     

Neuromuscular adaptations and correlates of knee functionality following ACL reconstruction

The objective of this research was to examine the dynamic restraint mechanism by establishing the neuromuscular characteristics of lower extremity muscles in anterior cruciate ligament reconstruction (ACLR) subjects. This study also investigated neuromuscular variables that relate to post‐ACLR functional outcome. Thirteen patients having undergone ACLR using the bone patella tendon bone graft at least 6 months prior participated in this study. Knee functionality (0‐ to 100‐point scale) was rated using the Cincinnati Knee Rating System. The median frequency of the electromyographic (EMG) recordings from the vastus medialis (VM) and vastus lateralis (VL) muscles together with the isokinetic quadriceps torque generated in 10° intervals between 80° and 10° knee flexion was determined for the noninvolved and involved limbs. Lower limb musculotendinous stiffness was also assessed for the noninvolved and involved limbs. Limb symmetry indexes were calculated for each of the physiological measures. Compared to the noninvolved limb, the median frequency of the EMG from the involved limb VM and VL muscles was significantly lower as was the quadriceps torque generated at the seven knee flexion intervals. In contrast, musculotendinous stiffness was significantly higher in the involved lower limb compared to the noninvolved limb. Significant, moderate correlations were identified between knee functionality and symmetry indexes for all variables except for the isokinetic quadriceps torque produced between 80°–70° and 20°–10° knee flexion. More functional ACLR subjects demonstrated enhanced motor unit recruitment reflective of less quadriceps muscle fiber atrophy together with increased quadriceps strength and musculotendinous stiffness of the lower limb musculature. © 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:126–135, 2008     

Urgent closed reduction of the dislocated cervical spine in New Zealand

Background

Emergent decompression, either by closed reduction or surgical decompression, of the acutely compressed cervical spinal cord is recognized as important in minimizing the neurological outcomes of these injuries. The aim of this study is to optimize New Zealand's capability to perform closed reductions.

Methods

Regional hospitals throughout New Zealand were surveyed on their capability to reduce acute cervical spine dislocations using traction. A systematic literature review was performed to investigate aspects of patient selection, reduction technique and the outcomes achieved with closed reduction of such injuries. This information was combined with our local experience to develop an evidence‐based guideline.

Results

Most (12/14) of the regional centres throughout New Zealand have recent experience, remain willing and have the resources necessary to reduce appropriate cervical spine injuries using traction. Fourteen published studies from nine countries detail a 75% success rate from 363 cases of attempted closed reduction, with the greatest neurological recovery noted in patients with shorter time period from injury to reduction. One patient suffered neurological worsening. The published protocols were compared and coupled with our local practice to create an online, step‐by‐step, evidence‐based reference to help clinicians in regional hospitals perform a safe and successful closed reduction.

Conclusion

To optimize the capability of inexperienced personnel to perform closed reductions in a safe and timely manner, we have developed an online, step‐by‐step, evidence‐based reference ( www.closedreduction.co.nz ). This forms part of New Zealand's strategy to achieve urgent cord decompression for appropriate cervical spinal cord injuries.     

Acute knee dislocation: an evidence based approach to the management of the multiligament injured knee

Traumatic knee dislocations are uncommon yet serious injuries that historically have had variable prognosis. The evaluation and management of traumatic knee dislocations remains controversial. Appropriate early management has been shown to have a significant impact on long term functional outcome. A comprehensive review of the recent literature is presented alongside our current approach to management.The dislocated knee is an under diagnosed injury which relies on a high index of clinical suspicion on presentation of any knee injury. There is now a degree of consensus regarding need for surgery, timing of surgery, vascular investigations, surgical techniques and rehabilitation protocols.Vigilant monitoring for neurovascular complications, appropriate investigations and early involvement of surgeons with a specialist interest in knee ligament surgeries is the key to successful management of these difficult injuries.     

Allograft Use in Anterior Cruciate Ligament Reconstruction

Anterior cruciate ligament (ACL) reconstruction is one of the most common procedures performed by orthopedic surgeons. While autograft reconstruction remains the gold standard, allograft tissues have become a controversial option for ACL reconstruction. No data currently exist regarding recent trends in graft choices, and no consensus exists over which graft type is most appropriate for which patient. In this article, we examine trends in ACL graft choice at our institution, and review the pertinent information a surgeon must consider when making this decision. We reviewed operating room records from 2002 to 2008 to determine trends in graft choice for primary single bundle ACL reconstruction. Total number of procedures performed, graft choices, and patient ages were recorded. Patients were divided into the following age groups: less than 16, 16 to 20, 21 to 30, 31 to 40, 41 to 50, and over 50. Percent of ACL reconstructions using allograft was calculated for each year, as well as for each age group. Data were analyzed for trends in ACL graft choice over this time period as well as for trends in graft choice by age. We hypothesized that the rate of allograft use in primary ACL reconstruction had increased over time and that allograft use was associated with higher patient age. We also review the risks, safety, and standards for tissue procurement. Allograft use increased significantly (p < 0.001) from 2002 (17%) to 2008 (46%). There was also a significant difference (p < 0.001) in average age of patients receiving allografts (40.4 years) and autografts (26.4 years). Allograft use was significantly associated with higher patient age (p < 0.05) and increased with each successive age group from a rate of 9.9% in patients under 16 to 79.9% in patients over 50. Our study found that allograft use in primary ACL reconstruction has significantly increased from 2002 to 2008 and is significantly more common in older patients.     

Management of periprosthetic fracture above total knee arthroplasty using intramedullary fibular allograft and plate fixation

We report a series of comminuted periprosthetic fractures above total knee arthroplasties in 3 patients who were treated by using an intramedullary fibular strut allograft and a lateral buttress plate. The patients, whose ages ranged from 74 to 90 years, were grossly osteopenic on radiographs. All 3 fractures healed in a satisfactory alignment without any complications. We believe this technique is a feasible treatment option for periprosthetic fractures in this difficult group of patients, having both biologic and mechanical advantages.     

Management of the painful knee

The painful knee is one of the most common musculoskeletal presentations to primary and secondary care. It is important to distinguish between acute and chronic causes of knee pain, since the urgency of diagnosis and management can be vastly different. This short review covers the common diagnoses that are frequently encountered, with a systematic approach to confirming the diagnosis, and a management strategy.     

Pivot‐shift test: Analysis and quantification of knee laxity parameters using a navigation system

Lachman, drawer, and pivot‐shift (PS) tests are important in the assessment of ACL reconstruction. The goal of this work was to analyze the reliability of the PS test using a navigation system, identifying a set of new quantitative parameters and evaluating their clinical relevance. Eighteen patients that underwent anatomic double‐bundle ACL reconstruction were included. The new dynamic parameters were: anteroposterior translation of the medial and lateral compartments and the joint center and internal/external and varus/valgus rotations of the joint. For each parameter we measured the peaks and the areas obtained during the test. Intratester repeatability, comparisons of pre‐ and postoperative laxities, and correlations between the PS peaks and the corresponding peaks obtained with standard static tests were evaluated. Areas, peaks, and static laxity outcomes were compared, grouping patients according to the preoperative International Knee Documentation Committee (IKDC) score. The PS test was reliable in identifying the surgical reconstruction. Correlation analysis showed good coefficients both for pre‐ and postoperative values. Patients with IKDC grade “D” had larger areas during the PS compared to patients with grade “C”. Our analysis is helpful for characterizing patient‐specific laxity and surgical performance, thus highlighting the clinical relevance of the PS test. © 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 28:164–169, 2010     

Management of extensor mechanism deficit as a consequence of patellar tendon loss in total knee arthroplasty: a new surgical technique

Extensor mechanism disruption is an uncommon but devastating complication of total knee arthroplasty. A new technique of extensor mechanism reconstruction for patellar tendon loss, after total knee arthroplasty, with the help of extensor mechanism composite allograft is described. Four patients with chronic extensor mechanism-deficient total knee arthroplasty were undertaken for revision surgery along with reconstruction of extensor mechanism with an innovative technique using an extensor mechanism composite allograft consisting of a patella-patellar tendon-tibial tubercle. On final follow-up, none of the patients had extensor lag but for 10 degrees of extensor lag in 1 patient only. Providing an environment for bone-to-bone healing both proximally as well as distally and supervised postoperative rehabilitation led to encouraging results in the management of a failed extensor mechanism after total knee arthroplasty.     

Altered loading in the injured knee after ACL rupture

Articular loading is an important factor in the joint degenerative process for individuals with anterior cruciate ligament (ACL) rupture. Evaluation of loading for a population that exhibits neuromuscular compensation for injury requires an approach which can incorporate individual muscle activation strategies in its estimation of muscle forces. The purpose of this study was to evaluate knee joint contact forces for patients with ACL deficiency using an EMG‐driven modeling approach to estimate muscle forces. Thirty athletes with acute, unilateral ACL rupture underwent gait analysis after resolving range of motion, effusion, pain, and obvious gait impairments. Electromyography was recorded bilaterally from 14 lower extremity muscles and input to a musculoskeletal model for estimation of muscle forces and joint contact forces. Gait mechanics were consistent with previous reports for individuals with ACL‐deficiency. Our major finding was that joint loading was altered in the injured limb after acute ACL injury; patients walked with decreased contact force on their injured knee compared to their uninjured knee. Both medial and lateral compartment forces were reduced without a significant change in the distribution of tibiofemoral load between compartments. This is the first study to estimate medial and lateral compartment contact forces in patients with acute ACL rupture using an approach which is sensitive to individual muscle activation patterns. Further work is needed to determine whether this early decreased loading of the injured limb is involved in the development of osteoarthritis in these patients. © 2012 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 31: 458–464, 2013     

Knee cartilage T2 relaxation times 3 months after ACL reconstruction are associated with knee gait variables linked to knee osteoarthritis

Osteoarthritis development after ACL reconstruction (ACLR) is not well understood. Investigators have examined associations between knee biomechanical alterations and quantitative MRI (qMRI) variables, reflective of cartilage health, 12–60 months following ACLR; however, none have done so early after surgery. As part of an exploratory study, 45 individuals (age, 23 ± 7 years) underwent motion analysis during walking and qMRI 3 months after ACLR. For each limb, peak knee adduction moment (pKAM) and peak knee flexion moment (pKFM) were determined using inverse dynamics and peak medial compartment force was calculated using a neuromusculoskeletal model. T₂ relaxation times in the medial compartment and linear regressions were used to determine the associations between gait variables and deep and superficial cartilage T₂ relaxation times in six regions. pKAM was positively associated with deep layer T₂ relaxation times within the femoral central and posterior regions when examined in the involved limb and from an interlimb difference perspective (involved limb – uninvolved limb). After adjusting for age, the association between interlimb difference of pKAM and interlimb difference of deep layer T₂ relaxation times in the tibial central region became significant (p = .043). Interlimb difference of pKFM was negatively associated with interlimb difference of deep layer T₂ relaxation times within the femoral central and posterior regions. These associations suggest that degenerative pathways leading to osteoarthritis may be detectable as early as 3 months after reconstruction. Preventative therapeutic techniques may need to be employed early in the rehabilitation process to prevent cartilage degradation.     

An unusual complication of knee arthroscopy: an extra-articular migrated asymptomatic broken probe from the knee joint

In large knee arthroscopy series, the complication rate has been reported to be between 2% and 8%. Although preventable in most cases, the incidence of instrument breakage remains approximately 3%. Despite this relatively frequent occurrence, few case reports have been published regarding these complications. In this case report, a patient carried a broken probe tip in her popliteal muscle belly for 5 years without symptoms. During arthroscopy, when the C-arm was temporarily not available, a probe tip had broken off and was left behind in the knee joint. It migrated through a popliteal hiatus into the popliteal fossa, and lodged in the medial head of the gastrocnemius muscle. When knee pain occurred 5 years later, the piece was located with fluoroscopy and was recovered without complications. This is the first such case reported in the English medical literature.     

老年膝关节外侧旋转脱位1例

正患者,男,69岁,摔伤后致左膝肿痛伴功能障碍。X线片提示:左膝关节脱位、髁间嵴撕脱可能(见图1A)。在当地医院进行手法复位(见图1B),1 d后来我院治疗。查体:左膝关节肿胀明显,皮肤无破损,浮髌试验+,关节屈伸0°~30°,前、后抽屉试验,Lachman试验,胫骨后沉,屈膝30°膝关节外旋试验(患侧-健侧10°),小腿外侧皮肤及足背皮肤感觉减退、麻木,足背伸无力,足背动脉及胫后动脉可触及。临床诊