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1.  Salter-Harris Type III and Type IV Combined Fracture of the Distal Femoral Epiphysis: A Case Report 
Case Reports in Medicine  2012;2012:317848.
Distal femoral physeal fractures are not common but have a high rate of complications. They generally follow one of the patterns described in the Salter-Harris classification. We present a case of combination of Salter-Harris type III and type IV injury. Our case was a 15-year-old boy who had a motor vehicle accident. There was swelling, ecchymosis, severe pain, and valgus deformity, because of medial proximal fracture fragment, on the left knee. We deemed that Salter-Harris type III and type IV combination fracture in our case has not been previously reported. We prepared this paper in consideration of its contribution to the literature.
PMCID: PMC3361168  PMID: 22666265
2.  In Vivo Motion of Femoral Condyles During Weight-Bearing Flexion After Anterior Cruciate Ligament Rupture Using Biplane Radiography 
The purpose of this study was to investigate in vivo three- dimensional tibiofemoral kinematics and femoral condylar motion in knees with anterior cruciate ligament (ACL) deficiency during a knee bend activity. Ten patients with unilateral ACL rupture were enrolled. Both the injured and contralateral normal knees were imaged using biplane radiography at extension and at 15°, 30°, 60°, 90°, and 120° of flexion. Bilateral knees were next scanned by computed tomography, from which bilateral three-dimensional knee models were created. The in vivo tibiofemoral motion at each flexion position was reproduced through image registration using the knee models and biplane radiographs. A joint coordinate system containing the geometric center axis of the femur was used to measure the tibiofemoral motion. In ACL deficiency, the lateral femoral condyle was located significantly more posteriorly at extension and at 15° (p < 0.05), whereas the medial condylar position was changed only slightly. This constituted greater posterior translation and external rotation of the femur relative to the tibia at extension and at 15° (p < 0.05). Furthermore, ACL deficiency led to a significantly reduced extent of posterior movement of the lateral condyle during flexion from 15° to 60° (p < 0.05). Coupled with an insignificant change in the motion of the medial condyle, the femur moved less posteriorly with reduced extent of external rotation during flexion from 15° to 60° in ACL deficiency (p < 0.05). The medial- lateral and proximal-distal translations of the medial and lateral condyles and the femoral adduction-abduction rotation were insignificantly changed after ACL deficiency. The results demonstrated that ACL deficiency primarily changed the anterior-posterior motion of the lateral condyle, producing not only posterior subluxation at low flexion positions but also reduced extent of posterior movement during flexion from 15° to 60°.
Key PointsThree-dimensional tibiofemoral kinematics and femoral condylar motion in ACL-deficient knees during upright weight-bearing flexion were measured using biplane radiography with the geometric center axis.ACL deficiency caused posterior subluxation of the lateral condyle with excess external femoral rotation at early flexion positions.On flexion from 15° to 60°, the lateral condyle moved slightly posteriorly in ACL deficiency leading to reduced extent of external femoral rotation.
PMCID: PMC3772605  PMID: 24149168
anterior cruciate ligament; injury; kinematics; tibiofemoral; femoral condyle; radiography
3.  Arthroscopic Lavage and Debridement for Osteoarthritis of the Knee 
Executive Summary
The purpose of this review was to determine the effectiveness and adverse effects of arthroscopic lavage and debridement, with or without lavage, in the treatment of symptoms of osteoarthritis (OA) of the knee, and to conduct an economic analysis if evidence for effectiveness can be established.
Questions Asked
Does arthroscopic lavage improve motor function and pain associated with OA of the knee?
Does arthroscopic debridement improve motor function and pain associated with OA of the knee?
If evidence for effectiveness can be established, what is the duration of effect?
What are the adverse effects of these procedures?
What are the economic considerations if evidence for effectiveness can be established?
Clinical Need
Osteoarthritis, the most common rheumatologic musculoskeletal disorder, affects about 10% of the Canadian adult population. Although the natural history of OA is not known, it is a degenerative condition that affects the bone cartilage in the joint. It can be diagnosed at earlier ages, particularly within the sports injuries population, though the prevalence of non-injury-related OA increases with increasing age and varies with gender, with women being twice as likely as men to be diagnosed with this condition. Thus, with an aging population, the impact of OA on the health care system is expected to be considerable.
Treatments for OA of the knee include conservative or nonpharmacological therapy, like physiotherapy, weight management and exercise; and more generally, intra-articular injections, arthroscopic surgery and knee replacement surgery. Whereas knee replacement surgery is considered an end-of-line intervention, the less invasive surgical procedures of lavage or debridement may be recommended for earlier and more severe disease. Both arthroscopic lavage and debridement are generally indicated in patients with knee joint pain, with or without mechanical problems, that are refractory to medical therapy. The clinical utility of these procedures is unclear, hence, the assessment of their effectiveness in this review.
Lavage and Debridement
Arthroscopic lavage involves the visually guided introduction of saline solution into the knee joint and removal of fluid, with the intent of extracting any excess fluids and loose bodies that may be in the knee joint. Debridement, in comparison, may include the introduction of saline into the joint, in addition to the smoothening of bone surface without any further intervention (less invasive forms of debridement), or the addition of more invasive procedures such as abrasion, partial or full meniscectomy, synovectomy, or osteotomy (referred to as debridement in combination with meniscectomy or other procedures). The focus of this health technology assessment is on the effectiveness of lavage, and debridement (with or without meniscal tear resection).
Review Strategy
The Medical Advisory Secretariat followed its standard procedures and searched these electronic databases: Ovid MEDLINE, EMBASE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews and The International Network of Agencies for Health Technology Assessment.
The keywords searched were: arthroscopy, debridement, lavage, wound irrigation, or curettage; arthritis, rheumatoid, osteoarthritis; osteoarthritis, knee; knee or knee joint.
Time frame: Only 2 previous health technology assessments were identified, one of which was an update of the other, and included 3 of 4 randomized controlled trials (RCTs) from the first report. Therefore, the search period for inclusion of studies in this assessment was January 1, 1995 to April 24, 2005.
Excluded were: case reports, comments, editorials, and letters. Identified were 335 references, including previously published health technology assessments, and 5 articles located through a manual search of references from published articles and health technology assessments. These were examined against the criteria, as described below, which resulted in the inclusion of 1 health technology assessment and its corresponding update, and 4 articles (2 RCTs and 2 level 4 studies) for arthroscopic lavage and 8 papers (2 RCTs and 6 level 4 studies) for arthroscopic debridement.
Inclusion Criteria
English-language articles from PubMed, EMBASE, Cochrane Systematic Reviews, and health technology assessments from January 1, 1995 onward
Studies on OA of the knee with a focus on the outcomes of motor function and pain
Studies of arthroscopic procedures only
Studies in which meniscal tear resection/meniscectomy (partial or full) has been conducted in conjunction with lavage or debridement.
Exclusion Criteria
Studies that focus on inflammatory OA, joint tuberculosis, septic joints, psoriatic joints (e.g., psoriatic knee joint synovitis), synovitis, chondropathy of the knee and gonarthrosis (which includes varotic gonarthrosis)
Studies that focus on rheumatoid arthritis
Studies that focus on meniscal tears from an acute injury (e.g., sports injury)
Studies that are based on lavage or debridement for microfracture of the knee
Studies in which other surgical procedures (e.g., high tibial osteotomy, synovectomy, have been conducted in addition to lavage/debridement)
Studies based on malalignment of the knee (e.g., varus/valgus arthritic conditions).
Studies that compare lavage to lavage plus drug therapy
Studies on procedures that are not arthroscopic (i.e., visually guided) (e.g., nonarthroscopic lavage)
Studies of OA in children.
Arthroscopic lavage or debridement, with or without meniscectomy, for the treatment of motor function symptoms and pain associated with OA of the knee.
Studies in which there was a comparison group of either diseased or healthy subjects or one in which subjects were their own control were included. Comparisons to other treatments included placebo (or sham) arthroscopy. Sham arthroscopy involved making small incisions and manipulating the knee, without the insertion of instruments.
Summary of Findings
In early OA of the knee with pain refractory to medical treatment, there is level 1b evidence that:
Arthroscopic lavage gives rise to a statistically significant, but not clinically meaningful effect in improving pain (WOMAC pain and VAS pain) up to 12 months following surgery. The effect on joint function (WOMAC function) and the primary outcome (WOMAC aggregate) was neither statistically nor clinically significant.
In moderate or severe OA of the knee with pain refractory to medical treatment, there is:
Level 1b evidence that the effect on pain and function of arthroscopic lavage (10 L saline) and debridement (with 10 L saline lavage) is not statistically significant up to 24 months following surgery.
Level 2 evidence that arthroscopic debridement (with 3 L saline lavage) is effective in the control of pain in severe OA of the medial femoral condyle for up to 5 years.
For debridement in combination with meniscectomy, there is level 4 evidence that the procedure, as appropriate, might be effective in earlier stages, unicompartmental disease, shorter symptom duration, sudden onset of mechanical symptoms, and preoperative full range of motion. However, as these findings are derived from very poor quality evidence, the identification of subsets of patients that may benefit from this procedure requires further testing.
In patients with pain due to a meniscal tear, of the medial compartment in particular, repair of the meniscus results in better pain control at 2 years following surgery than if the pain is attributable to other causes. There is insufficient evidence to comment on the effectiveness of lateral meniscus repair on pain control.
Arthroscopic debridement of the knee has thus far only been found to be effective for medial compartmental OA. All other indications should be reviewed with a view to reducing arthroscopic debridement as an effective therapy.
Arthroscopic lavage of the knee is not indicated for any stage of OA.
There is very poor quality evidence on the effectiveness of debridement with partial meniscectomy in the case of meniscal tears in OA of the knee.
PMCID: PMC3382413  PMID: 23074463
4.  Low-grade myofibroblastic sarcoma of the distal femur 
Low-grade myofibroblastic sarcoma (myofibrosarcoma) is described to be a distinct atypical myofibroblastic tumor often with fibromatosis-like features and predilection for head and neck. Low-grade myofibroblastic sarcoma of bone is extremely rare.
A 50-year-old woman was admitted to our hospital because she had experienced right knee pain for 2 years. Plain radiography showed a honeycombed lesion on the right distal femur, and computed tomography showed a bone tumor with cortex destruction invading the soft tissue. A biopsy specimen from the intraosseous lesion showed a hypocellular area of spindle cell proliferation with dense collagen deposition, which is reminiscent of a histological feature of desmoplastic fibroma. However, histological examination of the extraosseous lesion indicated a slightly hypercellular area containing scattered spindle-shaped atypical cells with enlarged nuclei, suggestive of low-grade sarcoma. Spindle-shaped atypical cells were immunohistochemically positive for SMA. A final diagnosis of low-grade myofibroiblastic sarcoma of the bone was made from a surgically resected specimen.
The patient was alive and well with no evidence of disease at 15 months after the surgery without any additional therapy.
Extensive sampling of a tumor may be necessary to determine the true nature of the tumor and to make an accurate diagnosis.
PMCID: PMC3540212  PMID: 23276766
Low-grade myofibroblastic sarcoma; Leiomyosarcoma; Desmoplastic fibroma; Biopsy
5.  Multiple Osteochondritis Dissecans of Knee Joint in a Patient with Wilson Disease, Focusing on Magnetic Resonance Findings 
Knee Surgery & Related Research  2013;25(4):225-229.
A 17-year-old man was admitted with a complaint of knee pain. He was diagnosed with Wilson disease by ophthalmologic and laboratory studies during hospitalization. Initial plain radiography of both knees showed multiple osteochondritis dissecans (OCD) on the medial and lateral femoral condyles of both knees. Subsequent magnetic resonance imaging showed multiple OCDs, which were symmetric on both knees. Subchondral cysts on the medial condyle and trochlear dysplasia were additionally evident on both femurs. We report this case with a focus on the imaging findings.
PMCID: PMC3867617  PMID: 24369002
Osteochondritis dissecans; Magnetic resonance imaging; Hepatolenticular degeneration
6.  Distal Femur Rotation Relates to Joint Obliquity in ACL-deficient Chinese 
The lower limb osteometry of Chinese differs from that of whites. The joint line of the knee in the coronal plane in Chinese is more medially inclined and the posterior condylar angle of the distal femur in the axial plane is larger. However, it is unclear whether there is any direct association between the coronal plane and axial plane osteometry.
We asked whether the joint line obliquity of the knee is related to the posterior condylar angle of the distal femur in young Chinese subjects.
Ninety-nine young Chinese patients with anterior cruciate ligament injuries were recruited. The lower limb alignment and joint line obliquity were measured using standing long radiographs of the whole lower limb. The rotational alignment of the distal femur was assessed in the axial cuts of the MRI.
The distal femur rotational alignment was associated with the obliquity of the knee in Chinese. The posterior condylar angle was 5° ± 2°. The knee was 5° ± 3° medially inclined.
The joint line of the knee in a group of young Chinese patients was more medially inclined than that of whites. The posterior condylar angle of the distal femur was larger. The presence of an association between distal femur rotational alignment and joint line obliquity in this group of young Chinese patients suggests a possible developmental cause explaining the difference in osteometry between races.
PMCID: PMC3613520  PMID: 23179120
7.  Multicentric giant cell tumor around the knee 
Indian Journal of Orthopaedics  2007;41(2):151-153.
A case of multicentric giant cell tumor with synchronous occurrence in all three bones around the knee is reported here in view of its rarity. A 33-year-old average built male reported with complaints of severe pain, gradually increasing swelling around the right knee. A 3 × 2 cm swelling was present on the lateral aspect of the distal end of the right femur and a 3 × 3 cm swelling on the proximal part of the right tibia. Plain X-ray of right knee showed subarticular eccentrically located expansile lytic lesion in the lateral tibia condyle, lateral condyle of femur and patella. Fine needle aspiration cytology and subsequent histology ascertained the diagnosis of giant cell tumor of the bone. The patient was treated successfully with curettage, bone grafting and methyl methacrylate cementing (Sandwich technique).
PMCID: PMC2989140  PMID: 21139769
Amputation; arthrodesis; arthroplasty; curettage; giant cell tumor
8.  Bilateral Volleyball-Related Deformity of the Little Fingers: Mallet Finger and Clinodactyly Mimic 
A 14-year-old male high school volleyball player was seen to evaluate right- and left-hand little-finger distal interphalangeal joint deformity and pain. His symptoms began during his second season of competitive play. The distal interphalangeal (DIP) joints of the little fingers flexed 20-30°, and a 10-15° valgus deformity was seen at the same joints. Pain was relieved with rest but returned immediately after playing volleyball, so plain radiographs were obtained. The flexion and valgus deformity was obvious on plain radiographs and through a clinical examination. Thus, a bilateral little-finger distal phalanx base epiphysis injury was seen. This injury is characterized by a biplanar Salter Harris physeal injury; type 5 on anteroposterior radiographs and type 2 on lateral plain radiographs. The deformity occurred as a result of competitive volleyball play. To our knowledge, this is the first reported case of a bilateral biplanar physial injury of the base of distal phalanges of the little fingers. Flexion and valgus deformities of DIP joints are a result of repeated micro traumas around the physis.
Key pointsAs a result of repeated micro traumas to the physial region, flexion and valgus deformities of the distal interphalangeal (DIP) joints should be occurred.Sports injuries to the hand often require treatment in orthopedic departments to avoid permanent deformities.Short- or long-term functional results can be gained by simple splinting procedures and abstention from play.
PMCID: PMC3737907  PMID: 24149318
Bilateral little-finger deformity; mallet finger; clinodactyly; volleyball sport injury; physis injury; hand pain
9.  Magnetic Resonance Imaging based Cartilage Loss in Painful Contra-Lateral Knees with and without Radiographic Joint Space Narrowing – Data from the Osteoarthritis Initiative (OAI) 
Arthritis and rheumatism  2009;61(9):1218-1225.
Magnetic resonance imaging (MRI) was used to assess whether knees with advanced radiographic disease (medial joint space narrowing = mJSN) encounter greater longitudinal cartilage loss than contra-lateral knees with earlier disease (no or less mJSN).
Participants were selected from 2678 cases in the Osteoarthritis Initiative, based on exhibition of bilateral pain, BMI>25, mJSN in one knee, no or less mJSN in the contra-lateral knee, and no lateral JSN in both knees. 80 participants (age 60.6±9.1 yrs) fulfilled these criteria. Medial tibial and femoral cartilage morphology was analyzed from baseline and 1-year follow-up sagittal DESSwe 3 Tesla MRI of both knees, by experienced readers blinded to the timepoint and mJSN status.
Knees with more radiographic mJSN displayed greater medial cartilage loss (-80 μm), assessed by MRI, than contra-lateral knees with less mJSN (-57μm). The difference reached statistical significance in participants with mJSN grade 2 or 3 (p=0.005 to p=0.08), but not in participants with mJSN grade 1 (p=0.28 to 0.98). In knees with more mJSN, cartilage loss increased with higher grades of mJSN (p=0.003 in the medial femur). Knees with mJSN grade 2 or 3 displayed greater cartilage loss in the weight-bearing medial femur than in the posterior femur or in the medial tibia (p=0.048).
Knees with advanced mJSN displayed greater cartilage loss than contra-lateral knees with less mJSN. These data suggest that radiography can be used to stratify fast structural progressors, and that MRI cartilage thickness loss is more pronounced at advanced radiographic disease stage.
PMCID: PMC2935616  PMID: 19714595
Progression; Joint Space Narrowing; Radiographic osteoarthritis; Cartilage loss; Magnetic Resonance Imaging
10.  Nonossifying fibroma presenting as an aneurysmal bone cyst: a case report 
Nonossifying fibroma is a common fibrous bone lesion in children that occurs in the metaphysis of the long bones of the lower extremities. The lesion rarely leads to aneurysmal bone cyst, which is characterized as a blood-filled space.
Case presentation
We present the case of a 13-year-old Japanese boy with a complaint of discomfort in the thigh and a small, well-defined, osteolytic lesion with cortical thinning located in the medullary space of the distal diaphysis of the femur. At 10-month follow-up, the size of the lesion had increased. Gadolinium-enhanced magnetic resonance imaging failed to detect any solid area. Curettage and bone graft were performed and confirmed a blood-filled cystic lesion. The pathological diagnosis of the cyst wall was that of nonossifying fibroma, suggesting aneurysmal bone cyst as a secondary change. An aneurysmal bone cyst is rarely found secondary to nonossifying fibroma, and the diaphyseal location is atypical for nonossifying fibroma, both of which made diagnosis challenging.
The current case is a reminder to clinicians that, although rare, nonossifying fibroma can be associated with aneurysmal bone cyst, and both can occur in the diaphysis of long bones.
PMCID: PMC3520689  PMID: 23194069
11.  Manifestations of Ollier's disease in a 21-year-old man: a case report 
Ollier's disease is a rare nonhereditary disorder characterized by multiple enchondromas with a predilection for unilateral distribution. Malignant changes in Ollier's disease may occur in adult patients. Radionuclide bone scanning is one method used to assess lesions depicted on radiographs or magnetic resonance images that are presumed to be enchondromas. Also, a bone scan may give a clue to the multifocal nature of the disease and it has been recommended that scintigraphy is useful in the monitoring of lesions and the development of any malignant transformation.
Case presentation
A 21-year-old man with a history of pathologic fractures of the right tibia and multiple limb surgeries related to Ollier's disease was referred to our nuclear medicine department. Radiographic assessment showed multiple radiolucent expansile lesions, suggestive of multiple enchondromas. A whole-body bone (99mTc-MDP) scan showed multiple foci of increased activity involving the proximal and distal right femur and tibia, proximal right humerus, distal right ulna, right metacarpals, metatarsals and phalyngeal tubular bones, consistent with unilateral distribution of the lesions. The long bones of the left hemi-skeleton were unremarkable, representing unilateral involvement of the skeleton. In this case, the intensity of uptake in the lesions of the lower extremity was high, raising the possibility of malignant degeneration of the enchondromas. Hence, the patient underwent surgical excision of the suspected lesions. Pathology analysis revealed their benign nature.
Although the malignant transformation of enchondromas is a well known phenomenon, it should be kept in mind that other etiologies can be considered as the cause of intensely increased uptake. Retrospective assessment of our patient revealed that the etiology of increased uptake in the lower limb lesions was due to previous insufficiency fractures and the possibility of malignant transformation was ruled out based on the pathology findings.
PMCID: PMC2726504  PMID: 19830216
12.  Autograft reconstructions for bone defects in primary total knee replacement in severe varus knees 
Indian Journal of Orthopaedics  2014;48(3):313-318.
Large posteromedial defects encountered in severe varus knees during primary total knee arthroplasty can be treated by cementoplasty, structural bone grafts or metallic wedges. The option is selected depending upon the size of the defect. We studied the outcome of autograft (structural and impaction bone grafting) reconstruction of medial tibial bone defects encountered during primary total knee replacement in severe varus knees.
Materials and Methods:
Out of 675 primary varus knees operated, bone defects in proximal tibia were encountered in 54 knees. Posteromedial defects involving 25-40% of the tibial condyle cut surface and measuring more than 5 mm in depth were grafted using a structural graft obtained from cut distal femur or proximal tibia in 48 knees. For larger, peripheral uncontained vertical defects in six cases, measuring >25 mm in depth and involving >40% cut surface of proximal tibial condyle, impaction bone grafting with a mesh support was used.
Bone grafts incorporated in 54 knees in 6 months. There was no graft collapse or stress fractures, loosening or nonunion. The average followup period was 7.8 years (range 5-10 years). We observed an average postoperative increase in the Knee Society Score from 40 to 90 points. There was improvement in the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores in terms of pain, stiffness and physical function during activities of daily living.
Bone grafting for defects in primary total knee is justified as it is biological, available then and is cost effective besides preserving bone stock for future revisions. Structural grafts should be used in defects >5 mm deep and involving 25-40% of the cut proximal tibial condyle surface. For larger peripheral vertical defects, impaction bone grafting contained in a mesh should be done.
PMCID: PMC4052033  PMID: 24932040
Osteoarthritis knee; autografting; bone defects; primary total knee replacement; severe varus deformity
13.  Optimizing femorotibial alignment in high tibial osteotomy  
Canadian Journal of Surgery  1999;42(5):366-370.
To study factors that affect femorotibial (F-T) alignment after valgus closing wedge tibial osteotomy.
Study design
A review of standardized standing radiographs. Femorotibial alignment was measured 1 year postoperatively for over- and under-correction. Changes in F–T alignment and in tibial plateau angle were measured.
An urban hospital and orthopedic clinic.
Eighty-two patients with osteoarthritis and varus femorotibial alignment underwent valgus closing wedge tibial osteotomy. Patients having a diagnosis of inflammatory arthritis or a prior osteotomy about the knee were excluded.
A 1° wedge removed from the tibia resulted in an average correction of F–T alignment of 1.2°. A knee that had increased valgus orientation of the distal femur had a greater degree of correction, averaging 1.46° in F–T alignment per degree of tibial wedge. This resulted in excessive postoperative valgus alignment for some patients who had increased valgus tilt of the distal femur. Optimal F–T alignment of 6° to 14° of valgus occurred when the postoperative tibial inclination was 4° to 8° of valgus.
There was a trend for knees with increased valgus orientation of the distal femur to have greater correction in F–T alignment after tibial osteotomy, likely because of a greater opening up of the medial joint space during stance. Surgeons need to account for this in their preoperative planning.
PMCID: PMC3788903  PMID: 10526522
14.  Structural and Functional Maturation of Distal Femoral Cartilage and Bone during Postnatal Development and Growth in Humans and Mice 
The size and shape of joints markedly affect their biomechanical properties, but the macroscopic 3-dimensional (3-D) mechanism and extent of cartilage and joint maturation during normal growth are largely unknown.
The purposes of this study were to qualitatively illustrate the development of the cartilage-bone interface in the knee during postnatal growth in humans and C57BL/6 wild-type mice, and to quantitatively define the 3-D shape using statistical shape modeling as well as to assess growth strain rates in the mouse distal femur.
Clinical computed tomography (CT) scans of asymptomatic knees (0.3–0.6mm in-plane resolution, 0.63mm slice thickness) were obtained from six patients between 4 to 12 years old. Micro-CT scans of mouse knees (9μm isotropic resolution) were from twenty-one mice between 12 to 120 days postnatal. Human and mouse images were compared qualitatively with 2-D images and 3-D reconstructions. Mouse femora shape parameters were determined with statistical shape modeling, and strain rates and directions during growth were mapped.
The attainment of cartilage-bone interface shape of the distal femur and proximal tibia were qualitatively similar in humans and mice, with marked differences in growth plate morphology. Mouse distal femur shape was described by 11 independent parameters that accounted for >90% of total shape variation during growth. Each shape parameter described changes in specific anatomical regions of the distal femur and varied with age. Shape parameters and strains in the medial and lateral condyles, as well as intercondylar notch, varied greatly between postnatal days 16 to 30. Directions of growth strain across ages corresponded well with the appearance of anatomical landmarks within the distal femur.
Accurate quantification of the cartilage-bone interface geometry is imperative for furthering the understanding of the macroscopic mechanisms of cartilage maturation and overall joint development.
PMCID: PMC3321216  PMID: 22480467
distal femur; postnatal development; growth strain; joint shape; statistical shape modeling
15.  Altered Knee Joint Mechanics in Simple Compression Associated with Early Cartilage Degeneration 
The progression of osteoarthritis can be accompanied by depth-dependent changes in the properties of articular cartilage. The objective of the present study was to determine the subsequent alteration in the fluid pressurization in the human knee using a three-dimensional computer model. Only a small compression in the femur-tibia direction was applied to avoid numerical difficulties. The material model for articular cartilages and menisci included fluid, fibrillar and nonfibrillar matrices as distinct constituents. The knee model consisted of distal femur, femoral cartilage, menisci, tibial cartilage, and proximal tibia. Cartilage degeneration was modeled in the high load-bearing region of the medial condyle of the femur with reduced fibrillar and nonfibrillar elastic properties and increased hydraulic permeability. Three case studies were implemented to simulate (1) the onset of cartilage degeneration from the superficial zone, (2) the progression of cartilage degeneration to the middle zone, and (3) the progression of cartilage degeneration to the deep zone. As compared with a normal knee of the same compression, reduced fluid pressurization was observed in the degenerated knee. Furthermore, faster reduction in fluid pressure was observed with the onset of cartilage degeneration in the superficial zone and progression to the middle zone, as compared to progression to the deep zone. On the other hand, cartilage degeneration in any zone would reduce the fluid pressure in all three zones. The shear strains at the cartilage-bone interface were increased when cartilage degeneration was eventually advanced to the deep zone. The present study revealed, at the joint level, altered fluid pressurization and strains with the depth-wise cartilage degeneration. The results also indicated redistribution of stresses within the tissue and relocation of the loading between the tissue matrix and fluid pressure. These results may only be qualitatively interesting due to the small compression considered.
PMCID: PMC3569885  PMID: 23424607
16.  Case Report: Multifocal Subchondral Stress Fractures of the Femoral Heads and Tibial Condyles in a Young Military Recruit 
Subchondral stress fractures of the femoral head may be either of the insufficiency-type with poor quality bone or the fatigue-type with normal quality bone but subject to high repetitive stresses. Unlike osteonecrosis, multiple site involvement rarely has been reported for subchondral stress fractures. We describe a case of multifocal subchondral stress fractures involving femoral heads and medial tibial condyles bilaterally within 2 weeks.
Case Description
A 27-year-old military recruit began having left knee pain after 2 weeks of basic training, without any injury. Subsequently, right knee, right hip, and left hip pain developed sequentially within 2 weeks. The diagnosis of multifocal subchondral stress fracture was confirmed by plain radiographs and MR images. Nonoperative treatment of the subchondral stress fractures of both medial tibial condyles and the left uncollapsed femoral head resulted in resolution of symptoms. The collapsed right femoral head was treated with a fibular strut allograft to restore congruity and healed without further collapse.
Literature Review
There has been one case report in which an insufficiency-type subchondral stress fracture of the femoral head and medial femoral condyle occurred within a 2-year interval.
Clinical Relevance
Because the incidence of bilateral subchondral stress fractures of the femoral head is low and multifocal involvement has not been reported, multifocal subchondral stress fractures can be confused with multifocal osteonecrosis. Our case shows that subchondral stress fractures can occur in multiple sites almost simultaneously.
PMCID: PMC3270163  PMID: 22161083
17.  The skiers knee without swelling or instability, a difficult diagnosis: a case report 
Skiing as a recreational activity has increased exponentially in the last twenty-years. Similar to any sporting activity, participants can sustain various types of injury, which provides the emergency departments with a continuous supply of patients. The injury pattern from the slopes has also changed over this time period, due to alterations and improvements in ski equipment. An increased diversity in alpine skiing techniques, as well as snowboarding and cross-terrain disciplines has also influenced this change.
We present a multi-media experience of a high-speed ski fall that caused a valgus-external rotation injury to the right knee that precluded the patient from further ski activity. There was no bruising, swelling or instability demonstrated and the patient returned to ski activities 24-hours post-injury. Although this injury appeared clinically benign initially, the patient complained of persistent pain around the right knee which was causing occupational difficulties. Following normal clinical assessment, the patient returned to work but continued to complain of persistent pain at the lateral aspect of the right knee. Magnetic Resonance Imaging (MRI) demonstrated extensive bone marrow oedema (BMO), a mild depression of the articular cortex compression with a small focus of articular cartilage disruption and microfractures of the lateral tibial plateau. The patient was treated conservatively and remains well with avoidance of impact exercises 14-months post-injury.
In the presence of any high speed injury, we would stress that regardless of initial normal investigations, clinical suspicion should remain paramount and not deter the physician from further investigation in the presence of continuing symptomatology.
PMCID: PMC1865549  PMID: 17448236
18.  Surgical Technique: Medial Collateral Ligament Reconstruction Using Achilles Allograft for Combined Knee Ligament Injury 
Previous approaches for medial collateral ligament (MCL) reconstruction have been associated with extensive exposure, risk of donor site morbidity with autografts, loss of motion, nonanatomic graft placement, and technical complexity with double-bundle constructs. Therefore, we implemented a technique that uses Achilles allograft, small incisions, and anatomic insertions to reconstruct the MCL.
Description of Technique
The MCL femoral insertion was identified, and a socket reamed over a guide pin. The Achilles bone plug was fixed in the socket and the tendon passed distally under the skin and fixed on the tibia, creating isometric reconstruction.
Patients and Methods
We evaluated 14 patients who had this MCL reconstruction. We determined range of knee motion, knee ligament laxity, functional outcome scores (International Knee Documentation Committee [IKDC]-subjective, Lysholm, Knee injury and Osteoarthritis Outcome Score [KOOS]), and activity level scores (Tegner, Marx). Followup range was 24 to 61 months.
Knee motion was maintained in 12 cases. Grade 0-1 + valgus stability was obtained in all 14 cases. In cases of MCL with primary ACL reconstruction, IKDC-subjective, Lysholm, and KOOS-sports scores were 91 ± 6, 92 ± 6, and 93 ± 12, respectively, and return to preinjury activity levels was achieved. In cases of MCL with revision ACL reconstruction, function was inferior, and patients did not return to their preinjury activity levels.
This technique uses allograft that provides bone-to-bone healing on the femur, requires small incisions, and creates isometric reconstruction. When performed with a cruciate reconstruction, knee stability can be restored at 2 to 5 years followup. In patients with MCL with primary ACL reconstruction, return to preinjury activity level in recreational athletes can be achieved.
PMCID: PMC3270177  PMID: 21660595
19.  Varus Gonarthrosis Predisposes to Varus Malalignment in TKA 
HSS Journal  2009;5(2):143-148.
Postoperative alignment is a predictor for long-term survival of total knee arthroplasty (TKA). The purpose of this study was to evaluate whether or not preoperative deformities predispose to intraoperative malposition of TKA components. A retrospective radiographic analysis of 53 primary TKA cases was performed. Preoperative AP hip to ankle and lateral knee radiographs were compared with postoperative views to evaluate component positioning. The following angles were measured: the hip–knee–ankle (HKA) angle expressing the mechanical axis of the leg, the mechanical lateral distal femur angle (mLDFA), the medial proximal tibia angle (MPTA), the posterior distal femur angle (PDFA), and the posterior proximal tibia angle (PPTA). Postoperative measurement of the HKA revealed 34.0% of the cases had a deviation of >±3° from neutral alignment. Sixteen knees (30.2%) were in varus and, with one exception, all presented with severe varus gonarthrosis prior to surgery with a mean tibiofemoral angle of 12.4° compared with 1.0° of valgus in the optimally aligned group. Patients (93.3%) with preoperative valgus malalignment showed optimal postoperative HKA. Odds ratios for malalignment of TKA for varus knees in comparison with valgus knees were 7.1 for HKA, 2.4 for MPTA, 4.9 for PDFA, and 1.7 for PPTA. The overall number of outliers in the presented data corresponds well with reports from other authors using different implants and guide systems. The presented data indicate that patients with preoperative varus alignment have a higher risk of postoperative implant malposition than patients with valgus alignment. The data supports that preoperative varus deformity predisposes to varus malposition of TKA. The risk for intraoperative malposition is significantly lower in valgus knees.
PMCID: PMC2744756  PMID: 19455367
20.  Three-dimensional reconstruction method for measuring the knee valgus angle of the femur in northern Chinese adults*  
The purpose of this study was to establish a method for measuring the knee valgus angle from the anatomical and mechanical axes on three-dimensional reconstruction imaging models, and to use this method for estimating an average knee valgus angle value for northern Chinese adults. Computed tomographic angiography data in DICOM format for 128 normal femurs from 64 adult subjects were chosen for analysis. After the femur images were subjected to three-dimensional reconstruction, the deepest point in the intercondylar notch (point A), the midpoint of the medullary cavity 20 cm above the knee-joint line (point B), and the landmark of the femoral head rotation center (point C) were identified on each three-dimensional model. The knee valgus angle was defined as the angle enclosed by the distal femoral anatomical axis (line AB) and the femoral mechanical axis (line AC). The average (mean±SD) of knee valgus angle for the 128 femurs was 6.20°±1.20° (range, 3.05° to 10.64°). Significant positive correlations were found between the knee valgus angles of the right and left sides and between the knee valgus angle and age. During total knee arthroplasty, choosing a valgus cut angle of approximately 6° may achieve a good result in reestablishing the natural mechanical alignment of the lower extremity for patients of northern Chinese ethnicity. Larger valgus cut angles should be chosen for older patients.
PMCID: PMC4129092  PMID: 25091990
Knee valgus angle; Three-dimensional reconstruction femoral model; Total knee arthroplasty; Northern Chinese adults; Preoperative design
21.  Osteoid Osteoma of the Thumb: A Case Report 
Hand (New York, N.Y.)  2010;5(4):423-426.
Osteoid osteoma is a rare occurrence in the hand, and only a small percentage affects the thumb and distal phalanges. An 18-year-old right-hand-dominant man presented to our office with an approximately 1-year history of left thumb pain without any history of trauma. He had seen several doctors previously and undergone multiple diagnostic tests with no definitive diagnosis. Plain radiographs and computed tomography at our institution were consistent with the diagnosis of osteoid osteoma. The patient was treated with surgical excision of the lesion without bone grafting. The diagnosis of osteoid osteoma was confirmed by pathology. At 6 months follow-up, the patient showed complete resolution of pain and full restoration of hand function. This case demonstrates that osteoid osteoma should not be forgotten as a differential diagnosis in patients with finger pain, especially in individuals who have not yet or just recently have reached skeletal maturity.
PMCID: PMC2988130  PMID: 22131926
Osteoid osteoma; Phalanx; Tumor; Resection; Thumb
22.  Gender and Condylar Differences in Distal Femur Morphometry Clarified by Automated Computer Analyses 
Journal of Orthopaedic Research  2011;30(5):686-692.
We elucidated the gender and condylar effects on distal femur morphology (DFM) while evaluating a newly developed computational framework that enables fully automated analyses of DFM in an objectively defined sagittal plane. Ninety high-resolution CT-acquired distal femur models from 51 males and 39 females were analyzed. The models were accurately characterized (mean least-squares fitting residual < 0.16 mm), and re-oriented to a unified sagittal plane; three morphometric measures were extracted from each model: the semi-major (a) and semi-minor (b) axis lengths of the best-fitted ellipse, and the radius (r) of the smallest flexion facet—a circle with the smallest radius best-fitted to the posterior articulating surface. Statistical analyses employing non-parametric repeated-measures ANOVA found: no significance difference between condyles or between limbs in any of the morphometric measures; significant gender effects on a, b, and r, but no gender effect on the aspect ratio (a/b). An inspection of statistical distributions of medial-lateral condyle size differences also revealed a gender difference. The findings promote a better understanding of DFM and its relation to knee mechanics and have implications on computer-aided surgery of the knee and gender-specific implant design.
PMCID: PMC3290733  PMID: 22025249
femur; morphometry; unified sagittal plane; non-parametric statistics
23.  High tibial osteotomy: closed wedge versus combined wedge osteotomy 
High tibial osteotomy is a common procedure to treat symptomatic osteoarthritis of the medial compartment of the knee with varus alignment. This is achieved by overcorrecting the varus alignment to 2-6° of valgus. Various high tibial osteotomy techniques are currently used to this end. Common procedures are medial opening wedge and lateral closing wedge tibial osteotomies. The lateral closing wedge technique is a primary stable correction with a high rate of consolidation, but has the disadvantage of bone loss and change in tibial condylar offset. The medial opening wedge technique does not result in any bone loss but needs to be fixated with a plate and may cause tibial slope and medial collateral ligament tightening. A relatively new technique, the combined valgus high tibial osteotomy, claims to include the advantages of both techniques without bone loss. Aim of this prospective randomized trial is to compare the lateral closing wedge with the combined wedge osteotomy in patients with symptomatic varus osteoarthritis of the knee.
A group of 110 patients with osteoarthritis of the medial compartment of the knee with 6-12° varus malalignment over 18 years of age are recruited to participate a randomized controlled trial. Patients are randomized to undergo a high tibial osteotomy, with either a lateral closing wedge technique or a combined wedge osteotomy technique. Primary outcome measure is achievement of an overcorrection of 4° valgus after one year of surgery, assessed by measuring the hip-knee-ankle angle. Secondary objectives are radiological scores and anatomical changes after high tibial osteotomy; pain, functional scores and quality of life will also be compared.
Combined high tibial osteotomy modification avoids metaphyseal tibial bone loss, decreasing transposition of the tibial condyle and shortening of the patellar tendon after osteotomy, even in case of great correction. The clinical results of the combined wedge osteotomy technique are very promising. Hypothesis is that the combined wedge osteotomy technique will achieve more accurate overcorrection of varus malalignment with fewer anatomical changes of the proximal tibia after one year.
Trial registration
Dutch Trial Registry (Netherlands trial register): NTR3898.
PMCID: PMC3996902  PMID: 24721597
Knee; Tibial; Osteotomy; Osteoarthritis; Combined; Medial; Unicompartmental; Proximal
24.  Osteoid Osteoma Treated with Radiofrequency Ablation 
Advances in Orthopedics  2015;2015:807274.
Purpose. Our aim is to evaluate the results of treatment with computed tomography (CT) guided percutaneous radiofrequency ablation for osteoid osteomas which were localized in a difficult area for operation. Materials and Methods. Glenoid, distal tibia, humerus shaft, proximal humerus, and in third finger of the hand proximal phalanx were involved in one patient. Proximal femur was involved in three patients, distal femur was involved in three patients, and proximal tibia was involved in two patients. 9 males and 4 females were aged 4 to 34 years (mean age: 18.5 years). All patients had pain and were evaluated with X-rays, CT, bone scintigraphy, and MRI. In all patients, RF ablation was performed with local anesthesia. The lesion heated to 90°C for 6 minutes. Results. All of the patients achieved complete pain relief after ablation and were fully weight bearing without any support. In all patients, there was soft tissue edema after the procedure. During follow-up, all patients were free from the pain and there was no sign about the tumor. There was no other complication after the process. Conclusion. CT guided RFA is a minimally invasive, safe, and cost-effective treatment for osteoid osteoma placed in difficult area for surgery.
PMCID: PMC4332763
25.  Control of Frontal Plane Knee Laxity during Gait in Patients with Medial Compartment Knee Osteoarthritis 
Patients with medial compartment knee osteoarthritis (OA) adopt an abnormal gait pattern, and often develop frontal plane laxity at the knee. The purpose of this study was to quantify the extent of frontal plane knee joint laxity in patients with medial knee OA and genu varum and to assess the effect of joint laxity on knee joint kinetics, kinematics and muscle activity during gait.
Twelve subjects with genu varum and medial compartment knee osteoarthritis (OA group) and twelve age-matched uninjured subjects underwent stress radiography to determine the presence and magnitude of frontal plane laxity. All subjects also went through gait analysis with surface electromyography of the medial and lateral quadriceps, hamstrings, and gastrocnemius to calculate knee joint kinematics and kinetics and co-contraction levels during gait.
The OA group showed significantly greater knee instability (p= 0.002), medial joint laxity (p = 0.001), greater medial quadriceps-medial gastrocnemius (VMMG) co-contraction (p = 0.043), and greater knee adduction moments (p = 0.019) than the control group. Medial joint laxity contributed significantly to the variance in both VMMG and the knee adduction moment during early stance.
The presence of medial laxity in patients with knee OA is likely contributing to the altered gait patterns observed in those with medial knee OA. Greater medial co-contraction and knee adduction moments bodes poorly for the long term integrity of the articular cartilage, suggesting that medial joint laxity should be a focus of interventions aimed at slowing the progression of disease in individuals with medial compartment knee OA.
PMCID: PMC3123521  PMID: 15325641
Knee osteoarthritis; Gait; Laxity; Co-contraction

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