Rotational instability of the knee: internal tibial rotation under a simulated pivot shift test

Introduction  Recently, several publications investigated the rotational instability of the human knee joint under pivot shift examinations and reported the internal tibial rotation as measurement for instrumented knee laxity measurements. We hypothesize that ACL deficiency leads to increased internal tibial rotation under a simulated pivot shift test. Furthermore, it was hypothesized that anatomic single bundle ACL reconstruction significantly reduces the internal tibial rotation under a simulated pivot shift test when compared to the ACL-deficient knee. Methods  In seven human cadaveric knees, the kinematics of the intact knee, ACL-deficient knee, and anatomic single bundle ACL reconstructed knee were determined in response to a 134 N anterior tibial load and a combined rotatory load of 10 N m valgus and 4 N m internal tibial rotation using a robotic/UFS testing system. Statistical analyses were performed using a two-way ANOVA test. Results  Single bundle ACL reconstruction reduced the anterior tibial translation under a simulated KT-1000 test significantly compared to the ACL-deficient knee (P < 0.05). After reconstruction, there was a statistical significant difference to the intact knee at 30° of knee flexion. Under a simulated pivot shift test, anatomic single bundle ACL reconstruction could restore the intact knee kinematics. Internal tibial rotation under a simulated pivot shift showed no significant difference in the ACL-intact, ACL-deficient and ACL-reconstructed knee. Conclusion  In conclusion, ACL deficiency does not increase the internal tibial rotation under a simulated pivot shift test. For objective measurements of the rotational instability of the knee using instrumented knee laxity devices under pivot shift mechanisms, the anterior tibial translation should be rather evaluated than the internal tibial rotation. This study was supported in part by a grant of the German Speaking Association of Arthroscopy (AGA).     

Multiple Proinsulin-Secreting Tumors of the Pancreas Treated by Laparoscopic Distal Pancreatectomy and Splenectomy

Background  Patients with pancreatic tumors that induce hypoglycemia present with a myriad of symptoms. Laboratory testing can frequently result in data challenging to the clinician to confirm the biochemical diagnosis. Proinsulin, in addition to insulin levels, may be essential in evaluating and diagnosing an insulinoma. Methods  The objective of this case report is to demonstrate the potential importance of proinsulin levels in the evaluation of tumor-induced hypoglycemia. We report a 49-year-old woman with an unusual clinical presentation. Unlike many patients with tumor-induced hypoglycemia, her fasting glucose levels were fairly unimpressive, her insulin levels were undetectable during a prolonged fast, and she had elevated proinsulin levels. Results  The inpatient fast was remarkable for levels of serum glucose 53 mg/dl or higher, a serum insulin <2 uIU/ml, C-peptide 0.7–1.1 (nl 0.8–3.1 ng/ml), and proinsulin 29.2–36.8 pmol/l (nl ≤ 18.8 pmol/l). CT scanning of the abdomen revealed multiple pancreatic lesions. A laparoscopic distal pancreatectomy led to the removal of multiple neuroendocrine tumors, which stained only for proinsulin and not for other pancreatic tumor markers. Postoperatively, she normalized her biochemical serum studies and has remained symptom-free 2 years later. Conclusions  The measurement of proinsulin plays an important part in the diagnostic workup of neuroendocrine tumors causing hypoglycemia. These potentially malignant tumors can be treated adequately with minimally invasive surgery.     

Painful neuroma requiring surgical excision after lower limb amputation caused by landmine explosions

This article reports an analysis of 75 consecutive lower limb amputees who developed painful neuroma requiring surgical excision after lower limb amputation following landmine explosions. This retrospective study analyses the results of 75 patients who were treated for painful neuroma after lower limb amputation following landmine explosions between the years 2000 and 2006. The average time period from use of prosthesis to start of symptoms suggesting neuroma was 9.6 months. The average time period from start of pain symptoms to neuroma surgery was 7.8 months. All clinically proven neuromas were surgically resected. In the mean follow-up of 2.8 years, all patients were satisfied with the end results and all were free of any pain symptoms. Painful stump with clinical diagnostic findings of neuroma described above may be regarded as neuroma without requiring any further imaging modalities and is an indication for surgery if conservative measures fail.     

Tethered cord syndrome in identical twins

Summary  The diagnosis of tethered cord syndrome (TCS) without typical conus medullaris symptoms and the radiological features such as a low set conus medullaris or dysraphic malformation is difficult. We report 11 year old identical twin brothers with TCS associated with the conus at the normal level. Their presenting symptom was progressive leg pain and both patients underwent surgical interruption of the filum terminale. The pain recurred in one patient treated surgically only after symptom became worse but resolved immediately in the other sibling treated promptly. We indicate the importance of early diagnosis and treatment of TCS to obtain excellent long-term outcome despite the absence of a low set conus or specific symptoms. Furthermore, when a twin or sibling of an affected person has neurological symptoms and the cutaneous signature of spinal dysraphism, radiological examination should be performed to establish the cause.     

RNA interference for noggin enhances the biological activity of bone morphogenetic proteins in vivo and in vitro

Noggin is a major extracellular antagonist to bone morphogenetic proteins (BMPs) which binds to BMPs and blocks binding of them to BMP-specific receptors and negatively regulates BMP-induced osteoblastic differentiation. In this study, we investigated the effect of noggin silencing by transfection of small interfering RNA (siRNA) on BMP-induced osteoblastic differentiation in vitro and ectopic bone formation in vivo induced by recombinant human BMP-2 (rhBMP-2). Noggin mRNA expression was up-regulated in response to rhBMP-2 in C2C12 cells, a myoblastic cell line, in dose- and time-dependent fashion as determined by real-time RT-PCR assay. Silencing of noggin expression by transfection of noggin siRNA suppressed BMP-stimulated noggin expression, resulting in acceleration of BMP-induced osteoblastic differentiation. For in vivo noggin silencing, siRNA was injected locally into back muscles and transfected into local cells by electroporation, where rhBMP-2-retaining (5 μg) collagen disks had been surgically placed. The implants were harvested at 2 weeks after surgery from experimental and control group mice and analyzed by radiological and histological methods. As a result, bone mineral content of ossicles ectopically induced by rhBMP-2 was significantly increased by silencing of noggin. Our findings suggest that silencing of noggin enhances the osteoblastic differentiation of BMP-responding cells in vitro and new bone formation induced by rhBMP-2 in vivo by eliminating negative regulation of the effects of BMP. RNA interference might be useful for intensifying the effects of BMP in promoting new bone (callus) formation in repair of damaged bone.     

How valid is the arthroscopic diagnosis of cartilage lesions? Results of an opinion survey among highly experienced arthroscopic surgeons

Aim  In general, arthroscopy is considered the “gold standard” for the evaluation of cartilage lesions. In this multicenter survey, we ascertained the general opinion of surgeons regarding arthroscopic cartilage diagnoses. Method  A total of 301 highly experienced arthroscopists (instructors of the AGA, the German-speaking society of arthroscopy) were contacted in writing with a request to complete the survey. Results  The data from 105 respondents (34.8% of those contacted) were used for the investigation. In the grading of the cartilage lesions, the Outerbridge classification was most frequently used (n = 87), followed by the ICRS protocol (n = 8) and the Insall score (n = 3). The majority (61%) of the arthroscopic surgeons felt that differentiation between healthy cartilage and low-grade cartilage lesions was simple. For differentiation between grade I and grade II lesions, and for differentiation between grade II and grade III lesions, 41.9 and 51.4%, respectively, thought that there was a “need for improvement”. In the case of grade IV lesions, 70.5% of the surgeons thought that the diagnosis was valid. The respondents also judged the utility of incorporating objective measurements (e.g., intraoperative biomechanical tests): 13.3% (n = 14) responded that such measurements would be “very useful” and 61.9% (n = 65) responded that they would be “somewhat useful”. Conclusions  Among surgeons, arthroscopy was not perceived to be as reliable as a “gold standard” for the diagnosis of cartilage lesions. The majority of experienced arthroscopists felt unsure of the results in general, or at least in some cases. A universal and definitive grading system for lesions appears to be needed. For questionable cases, measurement devices are needed for objective cartilage grading.     

Oncogenic osteomalacia: two case reports with surprisingly different outcomes

Oncogenic osteomalacia is a rare paraneoplastic syndrome of acquired hypophosphatemic osteomalacia, resulting from a deficit in renal tubular phosphate reabsorption, in which fibroblast growth factor 23 (FGF23) seems to be implicated. This condition is usually associated with a phosphaturic mesenchymal tumor of mixed connective tissue located in the bone or soft tissue. The clinical and the radiologic findings are the same as those seen in osteomalacia, and the biochemical features include renal phosphate loss, low serum phosphate and 1,25-(OH)₂ vitD₃ levels, increased alkaline phosphatase, and normal calcium, PTH, calcitonin, 25-OH-vitD₃ and 25,25-(OH)₂ vitD₃. We present two cases of oncogenic osteomalacia associated with phosphaturic mesenchymal tumors, which were histologically similar, but presented a completely different evolution. In the first patient, the tumor developed on the sole of the foot. Following removal of the mass, the symptoms resolved and biochemical and radiological parameters returned to normal. However, in the second patient, a liver tumor developed and resection did not resolve the disease. Multiple lesions appeared in several locations during follow-up. This disease usually remits with complete tumor resection. Nevertheless, if this is not possible, oral treatment with phosphate, calcium and calcitriol can improve the symptoms. If scintigraphy of the tumor shows octreotide receptors, patients may respond partially to therapy with somatostatin analogs, with stabilization of the lesion.     

The use of the Ki-67 marker in the pathological diagnosis of the epithelioid variant of renal angiomyolipoma

Objective:  Epithelioid angiomyolipoma (EAML) is a rare malignant variant of renal angiomyolipoma (AML). There were 34 cases of EAML reported in 25 studies (including this present study) over the past decade. About 68% were females and 32% males. The mean age was 40.1 years, 53% developed metastatic disease after nephrectomy, and eight patients had TSC. All cases are reported positive when stained with HMB-45 which also labels all classical AML. This study evaluates the use of Ki-67 (proliferation marker) in the pathological diagnosis of EAML and distinction from classical AML. Method:  Immunohistochemical reactions for Ki-67 were generated on multiple representative blocks of tissue obtained from two cases of HMB-45 positive EAML and four cases of classic AML and the percentage of positively staining cells estimated. Results:  Both cases of EAML were strongly positive for Ki-67 while all four classic AML were completely negative. Conclusion:  The Ki67 is a useful marker in which distinguishes the malignant epithelioid variant of AML from classic AML.     

A distinctive translocation carcinoma of the kidney [“rosette-like forming,” t(6;11), HMB45-positive renal tumor]

Objective  Recently, a novel renal carcinoma with specific clinical and histological characteristics and translocation t(6;11)(p21.1;q12 or q13) has been identified. We have found 11 cases in the literature, and we are adding another 3 cases. Materials and methods  Three cases were found in the Plzeň pathological register with approximately 15,000 cases of kidney tumors. There were two females and 1 male, aged 22, 24, and 39 years. Results  The sizes of the tumors were 40, 136, and 10 mm. Two tumors were found incidentally; the biggest one was self-palpated by a 24-year-old pregnant patient. Patients are without any signs of disease 42, 20, and 17 months after surgery. Conclusion  This tumor is a distinctive and rare translocation carcinoma of the kidney [t(6;11), HMB45 positive]. All cases with known clinical data arose in younger people. The malignant potential is probably low. The work was supported by Czech government research project MSM 0021620819.     

Transcutaneous electrical stimulation of urinary bladder in patients with spinal cord injuries

Introduction  The treatment of neurogenic dysfunctions of micturition, both surgical and conservative, aims primarily to protect upper urinary tract function. This goal can be achieved by lowering intravesical pressure and increasing urinary bladder capacity in the urine collection phase or by facilitating bladder emptying. Objective  The objective of this paper was to assess the outcome of transcutaneous stimulation of the urinary bladder in the treatment of neurogenic disorders of micturition. Materials and methods  The effect of urinary bladder stimulation was assessed in 22 patients (4 females, 18 males) with spinal injuries (19 with injuries to the lumbo-sacral spine and 3 with cervical spine injuries) treated at the Department of Rehabilitation of the Military Hospital in Bydgoszcz, Poland, in 2006 and 2007. The treatment consisted of 30 procedures of transcutaneous electrical stimulation of the urinary bladder. A pulsed sinusoid current was used with a pulse duration of 200 ms, break duration of 1,000 ms, intensity of 15–20 mA, frequency of 50 Hz, and duration of stimulation of 15 min. A urodynamic study was carried out in each patient at baseline and on completion of the electrical stimulation therapy (immediately and after 2 months). Results  Electrical stimulation of the neurogenic urinary bladder produced increases in the cystometric bladder capacity and reduction in the amount of residual urine (72% of patients), with reduction of intravesical pressure at peak urine flow (59% of the patients). The dynamic aspects of micturition also improved with increased peak voiding velocity in 77.3% of the patients. More than half of the patients (57%) still had elevated intravesical pressures during micturition that posed a risk to the function of the upper urinary tract despite significant decreases following the stimulation therapy. Micturition, which was absent at baseline, was restored in three patients. No local complications were observed. Conclusions  Transcutaneous electrical stimulation of the urinary bladder in patients with neurogenic bladder dysfunction improves lower urinary tract function. Urodynamic studies executed 2 months after finishing TES show persistent results.