Walking with a Posterior Cruciate Ligament Injury: A Musculoskeletal Model Study.

The understanding of the changes induced in the knee's kinematics by a Posterior Cruciate Ligament (PCL) injury is still rather incomplete. This computational study aimed to analyze how the internal loads are redistributed among the remaining ligaments when the PCL is lesioned at different degrees and to understand if there is a possibility to compensate for a PCL lesion by changing the hamstring's contraction in the second half of the swing phase. A musculoskeletal model of the knee joint was used for simulating a progressive PCL injury by gradually reducing the ligament stiffness. Then, in the model with a PCL residual stiffness at 15%, further dynamic simulations of walking were performed by progressively reducing the hamstring's force. In each condition, the ligaments tension, contact force and knee kinematics were analyzed. In the simulated PCL-injured knee, the Medial Collateral Ligament (MCL) became the main passive stabilizer of the tibial posterior translation, with synergistic recruitment of the Lateral Collateral Ligament. This resulted in an enhancement of the tibial-femoral contact force with respect to the intact knee. The reduction in the hamstring's force limited the tibial posterior sliding and, consequently, the tension of the ligaments compensating for PCL injury decreased, as did the tibiofemoral contact force. This study does not pretend to represent any specific population, since our musculoskeletal model represents a single subject. However, the implemented model could allow the non-invasive estimation of load redistribution in cases of PCL injury. Understanding the changes in the knee joint biomechanics could help clinicians to restore patients' joint stability and prevent joint degeneration.

Extracorporeal Shockwave Therapy in the Treatment of Nonunion in Long Bones: A Systematic Review and Meta-Analysis.

Background: Nonunion is one of the most challenging problems in the field of orthopedics. The aim of this study was to perform a systematic review of the literature to evaluate the effectiveness of extracorporeal shockwave therapy (ESWT) in the treatment of nonunion in long bones. Methods: We conducted a search of three databases (PubMed, Scopus, and Web of Science) and found 646 total publications, of which 23 met our inclusion criteria. Results: Out of 1200 total long bone nonunions, 876 (73%) healed after being treated with ESWT. Hypertrophic cases achieved 3-fold higher healing rates when compared to oligotrophic or atrophic cases (p = 0.003). Metatarsal bones were the most receptive to ESWT, achieving a healing rate of 90%, followed by tibiae (75.54%), femurs (66.9%) and humeri (63.9%). Short periods between injury and treatment lead to higher healing rates (p < 0.02). Conversely, 6 months of follow-up after the treatment appears to be too brief to evaluate the full healing potential of the treatment; several studies showed that healing rates continued to increase at follow-ups beyond 6 months after the last ESWT treatment (p < 0.01). Conclusions: ESWT is a promising approach for treating nonunions. At present, a wide range of treatment protocols are used, and more research is needed to determine which protocols are the most effective.

Percussion test: description and diagnostic accuracy of a new manual test for bone marrow edema of the knee.

BACKGROUND: Prompt diagnosis of bone marrow lesion (BML) is difficult but critical for correct treatment. Magnetic resonance imaging is the gold standard, although expensive and time consuming. Simple and reliable clinical test for BML detection is lacking. Aim of the study is to describe a new manual clinical test called Percussion Test (PT) and to statistically determine its diagnostic accuracy in BML, compared to MRI imaging. METHODS: After evaluation of the inclusion and exclusion criteria, 218 consecutive patients with unilateral knee pain and age comprised between 18 and 80 years old were enrolled in our observational prospective study. Informed consent was obtained for each patient. After medical history collection, PT was performed by a single operator as described. MRI was performed in the affected knee to detect the presence of BML. Coherence in PT and MRI assessment was evaluated in each quadrant of the knee via contingency tables, as sensitivity, specificity, NPV, PPV and diagnostic accuracy were calculated. RESULTS: No correlation with a positive PT was demonstrated for the covariables gender (p = 0.156), age (p = 0.272) and BMI (p = 0.639). PT showed a sensitivity ranging from 60.6 (40.6-80.6) to 79.5 (63.0-96.0) and a specificity ranging from 85.7 (80.0-91.5) to 96.0 (93.1-98.9) depending on knee quadrant. Diagnostic accuracy ranged from 81.6 (75.9-86.6) to 89.4 (84.6-93.2), and p-value was < 0.00001 in a chi-squared analysis for all quadrants. CONCLUSIONS: PT showed sensitivity and specificity values that are comparable with other clinical tests routinely adopted in clinical practice. In the absence of other reliable clinical test, PT has the potential to become a useful bedside tool in the diagnosis and management of BMLs.

Translation, cross-cultural adaptation, and validation of the Italian language Forgotten Joint Score-12 (FJS-12) as an outcome measure for total knee arthroplasty in an Italian population.

BACKGROUND: With ever-increasing numbers of patients undergoing elective total knee arthroplasty (TKA) and as TKA is performed in increasingly younger patients, patient demands and expectations have also increased. With improved patient outcomes, new PROMs with heightened discriminatory power in well-performing patients are needed. The present study aimed to translate and validate the Italian version of the Forgotten Joint Score (FJS-12) as a tool for evaluating pre-operative through longitudinal post-operative outcomes in an Italian population. METHODS: In this prospective study, patients with unilateral osteoarthritis, undergoing TKA surgery between May 2015 and December 2017 were recruited to participate in the study. The FJS-12 and WOMAC were collected pre-operatively and at six and 12 months post-operatively. According to the COSMIN checklist, reliability, internal consistency, validity, responsiveness, effect size, and ceiling effects and floor effects were evaluated. RESULTS: One hundred twenty patients completed the study, 66 of which participated in the evaluation of test-retest reliability. Good test-retest reliability was found (ICC = 0.90). The FJS-12 also showed excellent internal consistency (Cronbach α = 0.81). Construct validity with the WOMAC, as a measure of the Pearson correlation coefficient, was moderate (r = 0.45 pre-operatively; r = 0.46 at 6 months and r = 0.42 at 12 months post-operatively). From six to 12 months, the change was slightly greater for the WOMAC than for the FJS-12 patients (effect size d = 0.94; d = 0.75, respectively). At 12-months follow-up, the ceiling effects reflecting the maximum score were 12% for the FJS-12 and 6% for the WOMAC; however, scores within 10% of the maximum score were comprised 30% of the FJS-12 scores and 59% for the WOMAC. CONCLUSION: The Italian FJS-12 demonstrated strong measurement properties in terms of reliability, internal consistency, and construct validity in TKA patients. Furthermore, a more detailed look at ceiling effects shows a superior discriminatory capacity when compared to the WOMAC at 12-months follow-up, particularly in better-performing patients. TRIAL REGISTRATION: clinicaltrials.gov NCT03805490. Registered 18 January 2019 (retrospectively registered).

Novel treatment for hallux rigidus using a temporary metal interpositional device.

BACKGROUND: The aim of this prospective study is to evaluate the results of a consecutive series of patients suffering from grade II-III hallux rigidus who underwent a mobility preserving surgical technique consisting of resection arthroplasty with implantation of a temporary metal spacer. METHODS: Thirty consecutive patients, 18 female and 12 male with a diagnosis of a grade II-III hallux rigidus, not responding to conservative treatment, underwent a minimal resection arthroplasty followed by the implantation of a temporary metal interpositional device by the same surgeon. All spacers were removed after 6 months through a minimal incision under regional anaesthesia. Patients were clinically and radiographically evaluated at 3, 6, 12 months, and 5 years after spacer removal. RESULTS: The clinical AOFAS scores improved already at first follow-up and continued to improve over time with a statistically significant change until the first year. At 3, 6, and 12 months follow-ups, the number of patients with severely limited ROM (i.e. under 30°, that means grade II-III according to Coughlin and Shaurnas classification) significantly decreased. There were only two minor complications, so defined as both of which resolved spontaneously and did not affect the procedure's effectiveness. CONCLUSIONS: We observed good to excellent results with the use of this mobility preserving surgical technique for the treatment of symptomatic grades II and III hallux rigidus. The never before published procedure is easy to perform and inexpensive. LEVEL OF EVIDENCE: Level IV.

Does a high-fat diet affect the development and progression of osteoarthritis in mice?: A systematic review.

AIMS: The aim of this study was to systematically review the literature for evidence of the effect of a high-fat diet (HFD) on the onset or progression of osteoarthritis (OA) in mice. METHODS: A literature search was performed in PubMed, Embase, Web of Science, and Scopus to find all studies on mice investigating the effects of HFD or Western-type diet on OA when compared with a control diet (CD). The primary outcome was the determination of cartilage loss and alteration. Secondary outcomes regarding local and systemic levels of proteins involved in inflammatory processes or cartilage metabolism were also examined when reported. RESULTS: In total, 14 publications met our inclusion criteria and were included in our review. Our meta-analysis showed that, when measured by the modified Mankin Histological-Histochemical Grading System, there was a significantly higher rate of OA in mice fed a HFD than in mice on a CD (standardized mean difference (SMD) 1.27, 95% confidence interval (CI) 0.63 to 1.91). Using the Osteoarthritis Research Society International (OARSI) score, there was a trend towards HFD causing OA (SMD 0.78, 95% CI -0.04 to 1.61). In terms of OA progression, a HFD consistently worsened the progression of surgically induced OA when compared with a CD. Finally, numerous inflammatory cytokines such as tumour necrosis factor alpha (TNF-α), interleukin (IL)-1ß, and leptin, among others, were found to be altered by a HFD. CONCLUSION: A HFD seems to induce or exacerbate the progression of OA in mice. The metabolic changes and systemic inflammation brought about by a HFD appear to be key players in the onset and progression of OA.Cite this article: Bone Joint Res 2019;8:582-592.

Bone marrow lesions of the knee: longitudinal correlation between lesion size changes and pain before and after conservative treatment by extracorporeal shockwave therapy.

BACKGROUND: Bone marrow lesions (BMLs) of the knee have become a common finding on magnetic resonance imaging (MRI), leading to a growing interest in BML, not only for its potential role in the progression of several musculoskeletal conditions, but also for its clinical impact and treatment implications. At present, there is limited and conflicting evidence regarding whether or not pain may be correlated to BML size or not. AIM: To verify the longitudinal correlation between BML size and knee pain. DESIGN: Longitudinal. SETTING: Italian Orthopedic Institute. POPULATION: The study sample was composed of 72 patients, 27 males and 45 females, with a mean age of 55.9±10.22 years and a mean BMI of 26.1±3.7 kg/m2. All patients presented with BMLs and acute knee pain. METHODS: All 72 patients underwent a knee MRI before and 6 months after a course of high energy ESWT, in order to perform a quantitative measurement of the BML areas. KOOS (Knee Injury and Osteoarthritis Outcome Score) Pain subscale scores were obtained at the same time point. A regression analysis was performed to verify the correlation between knee BML size and KOOS pain subscale score before treatment and the correlation between the reduction of BML size and the improvement of KOOS pain score 6 months after treatment. RESULTS: A statistically significant correlation between the KOOS Pain subscale and the BML size (beta=-0.362 [CI95%: -0.019/-0.05], P=0.002) was demonstrated. The clinical score and BML area significantly improved after treatment (P<0.001). The clinical improvement was correlated to the BML size reduction (beta=0.254 [CI95%: 0.001/0.017], P=0.031). CONCLUSIONS: This study confirmed a significant correlation between the BML size and the intensity of knee pain. Furthermore, the before and after study using ESWT to treat symptomatic BMLs, revealed a correlation between size reduction of BML and KOOS pain subscale score improvement, demonstrating the utility of BML reduction as a therapeutic goal. Finally, ESWT was validated as a safe and potentially effective treatment of subchondral bone marrow lesions. CLINICAL REHABILITATION IMPACT: Our results confirm that severity of pain is correlated with BML size, and furthermore, demonstrate that increases and decreases in the amount of pain reflect growth or reduction in BML size, respectively. This information may be useful for rehabilitation and decrease the reliance on MRIs for checking the progress of bone lesions. Absence or marked reduction of pain should allow for the resumption of weight-bearing and more strenuous exercises for an adequate musculoskeletal recovery.

Calcific tendinopathy of the shoulder: clinical perspectives into the mechanisms, pathogenesis, and treatment.

Calcific tendinopathy (CT) of the shoulder is a common, painful condition characterized by the presence of calcium deposits in the rotator cuff tendons. Current theories indicate that CT may be the result of a cell-mediated process in which, after a stage of calcium deposition, calcifications are spontaneously resorbed. However, in a minority of cases, this self-healing process is somehow disrupted, resulting in symptoms. Recent literature shows an emerging role of biological and genetic factors underlying CT. This new evidence could supplement the classic mechanical theory of rotator cuff tendinopathy complicated by calcium precipitation, and it may also explain why the majority of the therapies currently in use are only able to provide partially satisfactory outcomes. This review aims to summarize the current knowledge about the pathological processes underlying CT of the shoulder and thereby justify the quest for advanced biological treatments of this condition when it becomes symptomatic.

All-polyethylene tibial components generate higher stress and micromotions than metal-backed tibial components in total knee arthroplasty.

PURPOSE: Most total knee arthroplasty tibial components are metal-backed, but an alternative tibial component made entirely of polyethylene (all-polyethylene design) exists. While several clinical studies have shown that all-poly design performs similarly to the metal-backed, the objective of this study is to perform a biomechanical comparison. METHODS: Loads, constraints and geometries during a squat activity at 120° of flexion were obtained from a validated musculoskeletal model and applied to a finite element model. Stresses in the tibia and micromotions at the bone-implant interface were evaluated for several implant configurations: (1) three different thicknesses of the cement penetration under the baseplate (2, 3 and 4 mm), (2) the presence or absence of a cement layer around the stem of the tibial tray and (3) three different bone conditions (physiological, osteopenic and osteoporotic bone). RESULTS: All-polyethylene tibial components resulted in significantly higher (p < 0.001) and more uneven stress distributions in the cancellous bone under the baseplate (peak difference: +128.4 %) and fivefold increased micromotions (p < 0.001). Performance of both implant designs worsened with poorer bone quality with peaks in stress and micromotion variations of +40.8 and +54.0 %, respectively (p < 0.001). Performance improvements when the stem was cemented were not statistically significant (n.s.). CONCLUSION: The metal-backed design showed better biomechanical performance during a squat activity at 120° of flexion compared to the all-polyethylene design. These results should be considered when selecting the appropriate tibial component for a patient, especially in the presence of osteoporotic bone or if intense physical activity is foreseen.

Long-term results of abrasion arthroplasty for full-thickness cartilage lesions of the medial femoral condyle.

PURPOSE: To evaluate the long-term functional results of arthroscopic abrasion arthroplasty for the treatment of full-thickness cartilage lesions of the medial femoral condyle. METHODS: Between 1990 and 1996, 75 consecutive patients with isolated chondral lesions of the medial femoral condyle were treated with arthroscopic chondral abrasion. A retrospective analysis of the clinical results of this cohort was performed. The patients were evaluated according to the Knee Society Score questionnaire preoperatively, at 10 years postoperatively, and at final long-term follow-up at a mean of 20 years. At final follow-up, they were also assessed according to the Western Ontario and McMaster Universities Osteoarthritis Index. Patients were divided according to the lesion size and by age, and the Kaplan-Meier survivorship function (with second operation taken as an endpoint) for the various groups was calculated. RESULTS: At a mean of final follow-up of 20 years (range, 16.94 to 23.94 years), a positive functional outcome (Knee Society Score ≥70 points or no reoperation) was recorded in 67.9% of the patients. Twenty-year survivorship in this cohort was 71.4% (95% confidence interval, 0.5690 to 0.8590). The survivorship was 89.5% for patients younger than 50 years and 55.7% for patients aged 50 years or older. The functional results for patients with lesions smaller than 4 cm(2) were significantly better than those for patients with lesions of 4 cm(2) or greater (P = .031). There were no statistical differences between patients with and without associated lesions at the time of surgery. CONCLUSIONS: Our hypothesis that there would be survivorship greater than 86% was disproved. However, arthroscopic abrasion arthroplasty can be a valid treatment for medial femoral condylar full-thickness defects of the knee, even in the long-term, particularly for younger patients and those with smaller lesions. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

L-arginine, asymmetric dimethylarginine, and symmetric dimethylarginine in plasma and synovial fluid of patients with knee osteoarthritis.

BACKGROUND: The aim of this study was to investigate the involvement of the nitric oxide (NO) pathway in osteoarthritis (OA). MATERIAL AND METHODS: The study groups consisted of 32 patients with knee OA and 31 healthy controls. In peripheral venous blood samples (from the OA patients and the controls) and in synovial fluid samples (from the OA patients), the concentrations of L-arginine (ARN), asymmetric dimethylarginine (ADMA), and symmetric dimethylarginine (SDMA) were evaluated. In plasma samples, thiobarbituric acid reactive substances (TBARS) were also measured. RESULTS: Plasma ARN concentrations were lower in the OA patients than in controls (53.55 ± 16.37 vs. 70.20 ± 25.68 µmol/l) (P<0.05), while plasma ADMA concentrations were similar. Accordingly, the ARN/ADMA ratio was lower in the OA patients than in the control group (80.85 ± 29.58 vs. 110.51 ± 30.48, P<0.05). Plasma SDMA and TBARS concentrations were higher in the OA patients than in controls (0.69 ± 0.15 vs. 0.60 ± 0.10 µmol/l, P<0.05 and 1.21 ± 0.29 vs. 0.55 ± 0.12, respectively) (P<0.001). In the OA patients, ADMA concentrations were significantly higher in the synovial fluid than in plasma (0.75 ± 0.09 vs. 0.69 ± 0.14 µmol/l, P<0.05), as were ARN concentrations (76.96 ± 16.73 vs. 53.55 ± 16.73 µmol/l) (P<0.00001). Conclusions These results indicate a poor availability of NO in the synovial fluid of the OA patients, which may contribute to the progression of OA. The decreased ARN/ADMA ratio and the increased SDMA and TBARS in the plasma of the OA patients suggest an impairment of endothelial function in these subjects.

Tibio-femoral kinematics in different total knee arthroplasty designs during a loaded squat: a numerical sensitivity study.

Total Knee Arthroplasty (TKA) is a very successful surgical procedure but clinical outcomes were reported to be affected by implant design, ligament balancing, alignment or patient-related anatomical factors. It was recently demonstrated that malpositioning of the TKA components and patient related anatomical factors can considerably alter tibio-femoral (TF) and patellofemoral maximum contact forces. However, up to now, how a component malpositioning and different soft-tissue anatomy changes TF knee kinematics was not yet fully investigated. The goal of this study was to evaluate how sensitive TF kinematics are to these factors during a simulated loaded squat for different TKA designs. Four TKA types (a fixed bearing, posterior stabilized prosthesis; a high flexion fixed bearing guided motion prosthesis; a mobile bearing prosthesis and a hinge prosthesis) were virtually implanted on the same virtual cadaver leg model which underwent a loaded squat between 0° and 120°. The reference models were then modified to simulate either component malpositioning in several directions or changes in ligaments geometry by change in the collateral ligament insertions. The results showed that, for all implant designs, TF kinematics were affected by changes in implant positioning and anatomical factors. While the ranges of motion predicted for all tested configurations were generally similar to the reference configuration for each type of TKA, the modifications resulted in shifts in the maximum and minimum values for the TF rotations and translations.

The Genesis II in primary total knee replacement: a systematic literature review of clinical outcomes.

Since its introduction in 1996, the Genesis II Total Knee System has produced good clinical results in patients undergoing primary total knee replacement. A systematic review of the literature-the first of its kind for this device-was undertaken to collect data on the Genesis II in order to provide a better understanding of its medium- to long-term performance. Of 124 Genesis II-related studies published in the literature, 11 met the eligibility criteria and were included in the final analysis. The included studies had a mean follow-up length of 38.1 months. Data from 1201 knees were available for review. Patients were an average of 70.5 years of age and predominantly female (63%). Findings indicated that the revision rate with this implant is low with up to 11.9 years of follow-up, with 14 revisions in total. The survival rate ranged from 100% at 1 and 2 years to 96.0% at 11.9 years. The mean Knee Society knee score improved 51.0 points from preoperative to postoperative evaluation. In conclusion, the Genesis II exhibited good clinical performance with up to 11 years follow-up, with an encouraging rate of survival and improvement in function. Additional studies with larger sample sizes and longer follow-up periods are needed to better understand the long-term performance of this implant.

Does primary or secondary chondrocalcinosis influence long-term survivorship of unicompartmental arthroplasty?

BACKGROUND: Coexistence of degenerative arthritis and calcium pyrophosphate dihydrate (CPPD) crystals (or radiological chondrocalcinosis) with osteoarthritis (OA) of the knees is frequent at the time of arthroplasty. Several studies suggest more rapid clinical and radiographic progression with CPPD than with OA alone. However, it is unclear whether chondrocalcinosis predisposes to higher risks of progression of arthritis in other compartments. QUESTION/PURPOSES: We questioned whether chondrocalcinosis influences clinical scores, degeneration of other compartments, rupture of the ACL, survivorship, reason for revision, or timing of failures in case of UKA. METHODS: We retrospectively reviewed 206 patients (234 knees) who had UKAs between 1990 and 2000. Of these 234 knees, 85 had chondrocalcinosis at the time of surgery and 63 of the knees subsequently had radiographic evidence of chondrocalcinosis observed during followup. We evaluated patients with The Knee Society rating system and compared function and radiographic progression in the other compartments of patients without and with chondrocalcinosis. RESULTS: The use of conventional NSAIDs, radiographic progression of OA in the opposite femorotibial compartment of the knee, failure of the ACL, and aseptic loosening did not occur more frequently among patients with chondrocalcinosis. The 15-year cumulative survival rates were 90% and 87% for the knees without and with chondrocalcinosis, respectively, using revision to TKA as the end point. CONCLUSION: Our findings show chondrocalcinosis does not influence progression and therefore is not a contraindication to UKA.

Do microfractures improve high tibial osteotomy outcome?

The aim of this study was to determine if microfractures improve the outcome of high tibial osteotomy in patients with medial compartmental osteoarthritis in genu varum. Forty patients presenting with Outerbridge grade III and IV chondropathies on the femoral and/or the tibial joint surface underwent high tibial osteotomy with Puddu plates (Arthrex, Inc, Naples, Florida) for primary medial compartment osteoarthritis in genu varum at our institution. Patients were randomly assigned to either the high tibial osteotomy plus microfractures group (A; n=20) or the high tibial osteotomy alone group (B; n=20). Final assessment was conducted 5 years postoperatively, including clinical response measured by the International Knee Documentation Committee (IKDC), Lysholm score, and patient satisfaction score. All patients were blinded to the treatment received and followed the same rehabilitation protocol. A statistically significant improvement between pre- and postoperative values was observed for Lysholm and IKDC scores in both groups, without any statistically significant difference between them. Regarding the satisfaction score, there were no differences between the 2 groups in terms of preoperative self-assessment (P>.05), whereas postoperative subjective satisfaction at 5-year follow-up was significantly higher in group A than in group B (P=.0036).Our study results provide further evidence that medial tibial osteotomy is an effective surgical option for treating a varus knee associated with medial degenerative arthritis in patients wishing to continue accustomed levels of physical activity. In particular, patient satisfaction was higher among those who underwent the combined treatment involving high tibial osteotomy to correct femorotibial angle and microfractures.

Asymmetric dimethylarginine (ADMA): an endogenous inhibitor of nitric oxide synthase and a novel cardiovascular risk molecule.

Asymmetric dimethylarginine (ADMA), a methyl derivate of the amino acid arginine, is produced by the physiological degradation of methylated proteins. ADMA is the major endogenous inhibitor of nitric oxide synthase (NOS), the enzyme which synthesizes nitric oxide (NO), a molecule endowed with important anti-atherosclerotic properties. Increased plasma ADMA concentrations cause impaired NO synthesis leading to endothelial dysfunction and atherosclerotic vascular disease. Increased plasma ADMA levels mainly occur following inhibition of the enzyme responsible for ADMA catabolism, dimethylarginine dimethylaminohydrolase (DDAH), by oxidative stress triggered by several cardiovascular risk factors. This paper reviews the effects on cardiovascular function produced by ADMA administration to experimental animals and humans. In addition, a number of clinical conditions associated with increased plasma ADMA concentrations are considered. Then the growing body of literature indicating that plasma ADMA levels have a predictive value for major cardiovascular events in prospective studies is discussed. Finally, an analysis is provided of the published data concerning the possibility to modulate plasma ADMA levels using drugs belonging to different pharmacological classes.

Clinical evaluation and treatment of posterior impingement in dancers.

Os trigonum impingement is a frequent cause of posterior ankle pain in ballet dancers because they need extreme plantar flexion during the execution of relevé in demipointe and en pointe positions. Clinical examination and standard and modified x-rays should be carried out to clearly identify the site and entity of the impingement. If a posterior impingement is clinically diagnosed, standard and modified magnetic resonance imaging should be also performed. From September 2005 to September 2006, we considered 186 young trainee ballet dancers. Twelve suffered from posterior ankle pain, and six of these had os trigona. We treated all the ballet dancers nonoperatively, and nine of them had good results. Conservative treatment failed in only three cases after 1-4 mos of physical and medical therapies, and, in these cases, good results were obtained through surgical excision of the accessory ossicle. Modified x-ray and magnetic resonance imaging help to determine the site and entity of the posterior impingement. If this is properly diagnosed, good results can be obtained through a nonoperative approach in a majority of cases.

Custom-made articulating spacer in two-stage revision total knee arthroplasty. An early follow-up of 14 cases of at least 1 year after surgery.

Total knee replacement (TKR) infection represents only a small percentage of all the potential complications in joint replacement, but one that can lead to disastrous consequences. Two-stage revision, which has been proven to be the most effective technique in eradicating infection, includes prosthesis removal, positioning of an antibiotic-loaded spacer, and systemic antimicrobial therapy for at least 6 weeks. It has been suggested that there is better performance in terms of range of motion, pain, extensor mechanism shortening, and spacer-related bone loss if articulating spacers are used instead of fixed spacers. In this paper, we describe our results in two-stage revision of infected total knee arthroplasty with a minimum follow-up of 12 months on 14 patients treated by antibiotic-loaded custom-made articulating spacer as described by Villanueva et al. (Acta Orthop 77(2):329-332, 2006). The mean flexion achieved after the second stage of the revision was 120 degrees , ranging from 97 degrees to 130 degrees. The mean Hospital for Special Surgery score was 84. At 1 year after surgery, none of the knees showed any evidence of recurrence of the infection. Articulating spacers are a suitable alternative to fixed spacers with good range of motion after reimplantation and effectiveness against total knee replacement deep infections.