Matias Costa-Paz

Osteonecrosis of the knee following arthroscopic meniscectomy in patients over 50-years old

We reviewed eight patients over 50-years old, with an initial diagnosis of medial meniscal tear confirmed with magnetic resonance imaging (MRI) and with no evidence of osteonecrosis. After arthroscopic meniscectomy, all patients had recurrent aggravated knee pain and reevaluation with MRI showed images compatible with osteonecrosis. The average age was 65 years (range 54 to 75 years). The mean time from MRI to surgery was 8 weeks (range 1 to 28 weeks). In five patients a total meniscectomy, and in three a partial meniscectomy with recontouring of the meniscus were performed. Surgical treatment was initially successful, but all eight patients returned to our office with recurrent aggravated pain in the treated knee. Reevaluation with MRI, at an average of 18 weeks postoperatively, found abnormalities at the medial condyle consistent with osteonecrosis. The purpose of this study is to report a potentially serious outcome after arthroscopic meniscectomy in patients over 50-years old.

Arthroscopic Fixation of Osteochondritis Dissecans of the Knee Clinical, Magnetic Resonance Imaging, and Arthroscopic Follow-up

Background Optimal treatment of osteochondritis dissecans of the knee is still controversial. Purpose To review a group of patients with osteochondritis dissecans of the knee who were treated with arthroscopic compressive screw fixation and who were evaluated with magnetic resonance imaging studies and a second-look arthroscopic procedure at follow-up. Study Design Case series; level of evidence, 4. Methods A total of 14 patients (15 knees) with osteochondritis dissecans of the knee were treated with arthroscopic titanium Herbert screw fixation of the osteochondral fragment. A second-look arthroscopic procedure was performed to remove hardware and to evaluate fragment stability. At final follow-up, magnetic resonance imaging studies were used to evaluate potential healing of the subchondral bone. Outcomes were clinically evaluated at a mean follow-up of 50 months (range, 25-104 months) by the Lysholm score and by the International Knee Documentation Committee score. Results At second-look arthroscopy, 14 of 15 knees showed evidence of a stable fragment with an intact smooth surface. According to magnetic resonance imaging parameters, 14 knees showed evidence of a healing process of the osteochondral fragment. The average Lysholm score improved 18 points from a mean of 79 preoperatively to 97 postoperatively, and according to the International Knee Documentation Committee score, 13 of 15 knees showed a normal result. Conclusion This study suggests that magnetic resonance imaging parameters of a healed osteochondral fragment and patients with satisfactory functional results correspond with arthroscopic evidence of fragment stability. According to this study, arthroscopic fixation with compressive screws is an effective method of repair for osteochondritis dissecans of the knee.

Tumors About the Knee Misdiagnosed as Athletic Injuries

Background: Musculoskeletal tumors may originally mimic a traumatic condition, and, on the basis of an erroneous diagnosis of an athletic injury, an invasive diagnostic or therapeutic procedure may be performed. We determined the number of such cases treated at our institution, and we analyzed the initial and final diagnoses as well as the changes in the indicated oncologic surgical technique due to the initial erroneous diagnosis. Methods: Twenty-five patients who had a bone or soft-tissue tumor about the knee that originally had been diagnosed as an athletic injury were referred to our institution. The complete clinical, radiographic, and pathological records were reviewed. Studies that had been performed prior to the invasive procedure and at the time of admission to our institution were evaluated to determine differences in the tumor stage and the oncologic treatment that was indicated at each time. Results: Of 667 knee tumors diagnosed in our institution, twenty-five (3.7%) previously had been treated with an intra-articular procedure as a result of a misdiagnosis of an athletic injury. The final diagnoses made at our institution were a benign tumor in eleven patients and a malignant tumor in fourteen. Oncologic surgical treatment was affected in fifteen of the twenty-five patients. Conclusions: When a knee tumor is initially misdiagnosed as an athletic injury, treatment may be adversely affected by the delay in diagnosis or an inappropriate invasive procedure that results in extension of the tumor. Initial poor-quality radiographs and an unquestioned original diagnosis despite persistent symptoms were the most frequent causes of an erroneous diagnosis. Level of Evidence: Prognostic study, Level IV (case series). See Instructions to Authors for a complete description of levels of evidence.

Localized pigmented villonodular synovitis of the posterior compartment of the knee: Diagnosis with magnetic resonance imaging

Localized Pigmented Villonodular Synovitis (LPVS) is a lesion that may affect any joint but is frequently found in the knee. Detection and diagnosis of this entity are clinically difficult, and plain roentgenograms are usually within normal limits. We present a case report of a LPVS localized at the posterior compartment of the knee that mimics a meniscal lesion. Magnetic resonance imaging (MRI) performed before the resection through an arthroscopic procedure helped to diagnose the tumor, which in this case had an infrequent location. MRI is a valuable clinical tool for the assessment of intraarticular tumors of the knee joint that otherwise may be misdiagnosed and treated as a meniscal tear.

Stress Fracture Nonunion at the Base of the Second Metatarsal in a Ballet Dancer A Case Report

Stress fractures are defined as spontaneous fractures of normal bone that are the result of repetitive stresses that are themselves harmless. Although the metatarsal shaft is the most common location of a stress fracture in the general population, the base of the second metatarsal is by far the most common site in ballet dancers. Few series published in the orthopaedic literature report a quick recovery of this fracture after conservative treatment, and cases of nonunion have not been previously reported. We report a nonunion at the base of the second metatarsal, secondary to a stress fracture, in a 24-year-old professional ballet dancer with successful outcome after surgical repair.

Patellofemoral arthritis treated with resurfacing implant: Clinical outcome and complications at a minimum two-year follow-up

BACKGROUND This study evaluated the clinical and radiographic outcomes of a series of patients treated with an anatomic inlay resurfacing implant, with a minimum two-year follow-up. METHODS Fifteen patients underwent patellofemoral-resurfacing procedures using a HemiCAP Wave Patellofemoral Inlay Resurfacing implant from 2010 to 2013. Clinical outcomes included: Visual Analog Scale (VAS), Lysholm score, Knee Society Score (KSS), and evaluation of Kujala, and Hospital for Special Surgery Patellofemoral score (HSS-PF). The postoperative complications were analyzed. RESULTS Nineteen knees were evaluated; the average follow-up was 35.2months. Fourteen were women, with an average age of 54years. The pre-operative/postoperative clinical results presented a significant improvement: VAS 8/2.5, Lysholm 31.9/85.8, KSS 39.8/82.5, Kujala 32.1/79.3 and Hospital for Special Surgery Patellofemoral score (HSS-PF) 15.9/90.6. A total of 87% of patients were either satisfied or very satisfied with the overall outcome. There were no radiographic signs of loosening. Seven postoperative complications were recorded: two presented ongoing knee pain, one postoperative stiffness, one patellar bounce due to maltracking, two ilio-tibial band syndrome, and one tibial anterior tuberosity osteotomy nonunion. Two patients underwent a total knee arthroplasty conversion and were considered a failure. None of these complications were implant related. CONCLUSIONS Patellofemoral inlay resurfacing for isolated patellofemoral arthritis was an effective and safe procedure with high levels of patient satisfaction. No mechanical implant failure was seen at a minimum two-year follow-up. This implant design appeared to be an alternative to the traditional patellofemoral prostheses. Concomitant osteochondral lesions, patellofemoral dysplasia or patellar maltracking might be poor prognostic factors for this type of implant.

Simultaneous rupture of the anterior cruciate ligament and a knee tumor

We report two patients with simultaneous lesions about the knee; a traumatic injury (acute anterior cruciate ligament rupture) and a musculoskeletal tumour; that may be particularly misleading for the treating surgeon.

Osteochondral Defects of the Knee treated with Mosaicplasty. Results at Eight Years of Follow-Up

Objectives: There are several surgical options described for osteochondral defects of the knee depending on the size, location and condition of subchondral bone. The main indication for a mosaicplasty procedure is a less than 4 cm2 femoral condyle lesion. The purpose of this study was to analyze a series of patients treated with mosaicplasty with average eight years of follow-up. Methods: We retrospectively evaluated sixty-two patients with osteochondral defects of the knee who underwent a mosaicplasty between 2001 and 2014 with a minimum follow-up of 2 years. Patients were evaluated using the Lysholm score, International Knee Documentation Committee Score (IKDC) and Kellgren-Lawrence radiographic scale. Results: The mean Lysholm score was 80.1 and IKDC was 66.7. Forty-two patients had isolated mosaicplasty and 20 patients presented an associated surgical procedure (osteotomy, ACL reconstruction, meniscectomy). There were no significant differences between the Lysholm and IKDC scores in these two groups. Conclusion: We consider that mosaicplasty is a satisfactory procedure with good functional results in patients with focal articular cartilage lesions of the knee.

Mycotic Infection post ACL Reconstruction: Preventive Measures

Objectives: There are several studies in literature of septic arthritis after the ACL arthroscopic reconstruction related to bacterial germs. However, fungi infection is likely infrequent generating a massive bone loss with a catastrophic result. The purpose of this study was to describe preventive measures to decrease the mycotic infection after ACL reconstruction. Methods: Since 2005, we have diagnosed and treated 22 immunocompetent patients who underwent a surgery of an ACL lesion in other institutions in the country. Form these cases, we analyzed 19 which developed mycotic infection and an oncologic debridement was performed to control the pathology. In this series, we considered the initial surgery, the number of toilettes performed until their referral, magnitude of bone loss and final outcome. There were 5 other patients who consulted for mucormycosis, who finally were treated in other hospitals. Results: Epidemiology of mucormycosis is not clear. The exact cause is unknown due to heterogeneous data, different places and surgeons, facilities and type of surgical instruments in this series. In spite of not knowing the cause of the infection, several alternatives were evaluated in a non systematic way. Most of them related to the surgery room, sterilization place of the surgical tools, use of sterilizing liquids, cleanliness of lumen and cannulated bits. Instruments used during surgery were also evaluated: fields, shaver blades, drill types, ACL reconstruction fixation method. It is doubtful if the type of graft to reconstruct the ACL had any relation with infections. Among ideal preventive measures, the following are described: Surgery room with temperature and humidity control. Not using sterilizing liquids. Optimal preparation of surgical tools with adequate cleanliness of lumen and cannulated bits performed by adequate personnel. Sterilize in the same place where the surgery will be performed. Use of adequate instruments. The use of the central third of the patellar tendon had less incidence of infection. Conclusion: Taking into account these preventive measures, the incidence of this aggressive and devastating complication should be decreased.

ACL Revision: Clinical Evaluation, Magnetic Resonance and Return to Sports one Year after Surgery

Objectives: The purpose of this study was to evaluate a series of patients one year after an ACL revision with clinical evaluation and MRI, to consider their condition before returning to sports activities. Methods: A descriptive, prospective and longitudinal study was performed. A series of patients who underwent an ACL revision between March 2014 and March 2015 were evaluated after one year post surgery. They were evaluated using the Lysholm score, IKDC, Tegner, artrometry and MRI (3.0 t). A signal pattern and osteointegration was determined in the MRI. Graft signal intensity of the ACL graft using the signal/noise quotient value (SNQ) was also determined to evaluate the ligamentatization process state. Results: A total of 18 male patients were evaluated with a mean age of 31 years old.Average scores were: Lysholm 88 points, IKDC 80 points, Pre-surgical Tegner 9 points and postoperative 4 points. Artrhometry (KT1000) at 20 newtons showed a side to side difference of less than 3 mm in 88%. Only 44% of patients returned to their previous sport activity one year after revision.The MRI showed a heterogeneous signal in neoligaments in 34% of patients. SNQ showed graft integration in only 28%. Synovial fluid was found in bone-graft interphase in 44% of tunnels, inferring partial osteointegration. The heterogeneous signal was present in 50% of patients who did not return to the previous sport level activity. (Fisher statistics: p = 0.043) There were no meaningful differences in patients with auto or allografts. Conclusion: Although the clinical evaluation was satisfactory, only 44% of patients returned to the previous level of sport activity one year after the ACL surgery. The ligamentatization process was found in 28% of knees evaluated with MRI one year later. Partial osteointegration is inferred in 44%. Results showed a meaningful relation between the signal of neoligaments in the MRI and the return to sport activity in said series of patients. MRI is a useful tool to consider the return to sports one year after the ACL revision.