Clinical Outcomes Following Biologically Enhanced Patch Augmentation Repair as a Salvage Procedure for Revision Massive Rotator Cuff Tears.

PURPOSE: To evaluate the clinical outcomes of patients who underwent biologically enhanced patch augmentation repair for the treatment of revision massive rotator cuff tears. METHODS: Twenty-two patients who underwent arthroscopic and mini-open rotator cuff repair using a patch augmented with platelet-rich plasma and concentrated bone marrow aspirate (cBMA) for revision massive (≥2 tendons) rotator cuff tears from 2009 to 2014, with a minimum 1-year follow-up, were included in the study. In this procedure the medial side of the graft is secured to the rotator cuff tendon remaining medially. American Shoulder and Elbow Surgeons (ASES), Simple Shoulder Test, and postoperative Single Assessment Numerical Evaluation scores were evaluated. To determine the clinical relevance of ASES scores, the minimal clinically important difference, substantial clinical benefit (SCB), and the patient-acceptable symptomatic state (PASS) thresholds were used. Clinical success or failure was defined based on whether the patient reached the SCB threshold. In the laboratory, cellular counting along with the concentration of connective tissue progenitor cells were performed on patch samples from the day of surgery. Scaffolds were processed histologically at days 0, 7,14, and 21 of culture. RESULTS: Patients had significant improvement in the Simple Shoulder Test (2.6 ± 3.0pre vs 5.2 ± 4.2post, P = .01), whereas improvement in pain scores was found to be nonsignificant (5.6 ± 2.5pre vs 4.2 ± 3.4post,P = .11) at final follow-up. Mean ASES improved by Δ14.6 ± 33.4 points; however, this did not reach statistical significance (40.2 ± 21.6pre vs 53.9 ± 31.4post,P = .10). With regards to ASES score, 45% of patients achieved the minimal clinically important difference, 41% the SCB, and 32% reached or exceeded the PASS criteria. At 21 days, there was a significantly greater cell count in scaffolds from patients who had clinical success than those who were failures (P = .02). CONCLUSIONS: Only 41% of patients undergoing biologically enhanced patch augmentation repair reached substantial clinical benefit, whereas 32% reached or exceeded the PASS criteria. LEVEL OF EVIDENCE: Case Series: Level IV.

High Clinical Failure Rate After Latissimus Dorsi Transfer for Revision Massive Rotator Cuff Tears.

PURPOSE: To evaluate the clinical success rate, along with risk factors for failure, in patients undergoing latissimus dorsi transfer for the treatment of massive, irreparable, previously failed rotator cuff tears. METHODS: We performed a retrospective chart review of prospectively collected data from an institutional shoulder outcome registry. All patients who underwent latissimus dorsi transfer for previously failed rotator cuff repair between 2006 and 2013 with a minimum follow-up period of 1 year were included in the study. The indications for inclusion were large (≥2 tendons), retracted, chronic rotator cuff tears with fatty infiltration or atrophy for which prior surgical repair had failed. Preoperative and postoperative American Shoulder and Elbow Surgeons (ASES) and Simple Shoulder Test scores were collected, along with postoperative Single Assessment Numerical Evaluation scores. Complications and clinical failures (Δ in ASES score <17) were recorded. Patient demographic and tear characteristics were evaluated as potential risk factors for failure. RESULTS: A total of 22 patients (mean age, 53 ± 6 years) were included in the study, with a mean follow-up time of 3.4 ± 1.1 years. Over 63% of patients (n = 14) reported undergoing 2 or more prior failed rotator cuff repairs. Patients undergoing latissimus dorsi transfer showed significant improvements in ASES scores (from 35.2 ± 21.9 preoperatively to 55.8 ± 22.9 postoperatively, P = .001), Simple Shoulder Test scores (from 3.5 ± 3.1 preoperatively to 5.2 ± 3.4 postoperatively, P = .002), and pain scores (from 5.9 ± 2.8 preoperatively to 4.6 ± 4.3 postoperatively, P = .002) at final follow-up. The complication rate after latissimus transfer was 27%. The rate of revision to reverse total shoulder arthroplasty was 13.6% (n = 3) after a mean of 2.7 years, and the clinical failure rate was 41% (n = 9) at final follow-up. An acromiohumeral interval of less than 7 mm (P = .04) and high-grade fatty infiltration (grade 3 or greater, P = .004) were significant preoperative risk factors for clinical failure. CONCLUSIONS: Latissimus dorsi tendon transfer resulted in a clinical failure rate of 41% and complication rate of 27%, with an acromiohumeral interval of less than 7 mm and high-grade fatty infiltration being associated with postoperative failure. LEVEL OF EVIDENCE: Level IV.

Recurrent Shoulder Instability: Do Morbidity and Treatment Differ Based on Insurance?

BACKGROUND: Patients with public insurance often face barriers to obtaining prompt orthopaedic care. For patients with recurrent traumatic anterior shoulder instability, delayed care may be associated with increasing bone loss and subsequently more extensive surgical procedures. PURPOSE/HYPOTHESIS: The purpose of this study was to evaluate whether differences exist in patients undergoing treatment for shoulder instability between those with Medicaid versus non-Medicaid insurance. We hypothesized that at the time of surgery, Medicaid patients would have experienced greater delays in care, would have a more extensive history of instability, would have more bone loss, and would require more extensive surgical procedures than other patients. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Patients were identified who underwent surgical stabilization for traumatic anterior shoulder instability between January 1, 2011, and December 1, 2015, at a single sports medicine practice. Clinic, billing, and operative records were reviewed for each patient to determine age, sex, insurance type, total number of instability episodes, time from first instability episode to surgery, intraoperative findings, and procedure performed. Glenoid bone loss was quantified by use of preoperative imaging studies. RESULTS: During this time period, 206 patients (55 Medicaid, 131 private insurance, 11 Tricare, 9 workers' compensation) underwent surgical stabilization for traumatic anterior shoulder instability. Average wait time from initial injury to surgery was 1640 days (95% CI, 1155-2125 days) for Medicaid patients compared with 1237 days (95% CI, 834-1639 days) for others (P = .005). Medicaid patients were more likely to have sustained 5 or more instability events at the time of surgery (OR, 3.3; 95% CI, 1.64-6.69; P = .001), had a higher risk of having 15% or more glenoid bone loss on preoperative imaging (OR, 3.5; 95% CI, 1.3-10.0; P = .01), and had a higher risk of requiring Latarjet or other open stabilization procedures as opposed to an arthroscopic repair (OR, 3.0; 95% CI, 1.5-6.2; P = .002) when compared with other patients. CONCLUSION: Among patients undergoing surgery for traumatic anterior shoulder instability, patients with Medicaid had significantly more delayed care. Correspondingly, they reported a more extensive history of instability, were more likely to have severe bone loss, and required more invasive stabilization procedures.

Postoperative Pain After Surgical Treatment of Ankle Fractures: A Prospective Study.

BACKGROUND: Postoperative pain after fixation of ankle fractures has a substantial effect on surgical outcome and patient satisfaction. Patients requiring large amounts of narcotics are at higher risk of long-term use of pain medications. Few prospective studies investigate patient pain experience in the management of ankle fractures. METHODS: We prospectively evaluated the pain experience in 63 patients undergoing open reduction and internal fixation of ankle. The Short-Form McGill Pain Questionnaire was administered preoperatively and postoperatively (PP) at 3 days (3dPP) and 6 weeks (6wPP). Anticipated postoperative pain (APP) was recorded. RESULTS: No significant differences were found between PP, APP, and 3dPP; however, 6wPP was markedly lower. Significant correlations were found between PP and APP and between preoperative and postoperative Short-Form McGill Pain Questionnaire scores. PP and APP were independent predictors of 3dPP; however, only APP was predictive of 6wPP. Sex, age, and inpatient versus outpatient status were not notable factors. No statistically significant differences were found in pain scores between fracture types. CONCLUSIONS: Both preoperative pain severity and anticipated postoperative pain are predictive of postoperative pain levels. Orthopaedic surgeons should place a greater focus on the postoperative management of patient pain and expectations after surgical procedures.

The Scleroderma Hand: Manifestations of Disease and Approach to Management.

Scleroderma is a rare autoimmune connective tissue disorder that often affects the hands. Manifestations in the hands include calcium deposits within the soft tissues that cause pain and may ulcerate through the skin, digital ischemia resulting in chronic wounds and digital gangrene, and joint contracture. Because of the underlying disease, patients with scleroderma have poorly vascularized tissue and a deficient soft tissue envelope, which make surgery particularly challenging. However, when undertaken with care, surgical intervention is often the best option for addressing the disabling hand conditions that so often accompany this disease.

Chondral Injuries and Irreparable Meniscal Tears Among Adolescents With Anterior Cruciate Ligament or Meniscal Tears Are More Common in Patients With Public Insurance.

BACKGROUND: Access to health care services is a critical component of health care reform and may differ among patients with different types of insurance. Hypothesis/Purpose: The purpose was to compare adolescents with private and public insurance undergoing surgery for anterior cruciate ligament (ACL) and/or meniscal tears. We hypothesized that patients with public insurance would have a delayed presentation from the time of injury and therefore would have a higher incidence of chondral injuries and irreparable meniscal tears and lower preoperative International Knee Documentation Committee (IKDC) scores than patients with private insurance. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: This was a retrospective study of patients under 21 years of age undergoing ACL reconstruction and/or meniscal repair or debridement from January 2013 to March 2016 at a single pediatric sports medicine center. Patients were identified by a search of Current Procedural Terminology (CPT) codes. A chart review was performed for insurance type; preoperative diagnosis; date of injury, initial office visit, and surgery; preoperative IKDC score; intraoperative findings; and procedures. RESULTS: The study group consisted of 119 patients (mean age, 15.0 ± 1.7 years). Forty-one percent of patients had private insurance, while 59% had public insurance. There were 27 patients with isolated meniscal tears, 59 with combined meniscal and ACL tears, and 33 with isolated ACL tears. The mean time from injury to presentation was 56 days (range, 0-457 days) in patients with private insurance and 136 days (range, 0-1120 days) in patients with public insurance ( P = .02). Surgery occurred, on average, 35 days after the initial office visit in both groups. The mean preoperative IKDC score was 53 in both groups. Patients with meniscal tears with public insurance were more likely to require meniscal debridement than patients with private insurance (risk ratio [RR], 2.3; 95% CI, 1.7-3.1; P = .02). Patients with public insurance were more likely to have chondral injuries of grade 2 or higher (RR, 4.4; 95% CI, 3.9-5.0; P = .02). CONCLUSION: In adolescent patients with ACL or meniscal tears, patients with public insurance had a more delayed presentation than those with private insurance. They also tended to have more moderate-to-severe chondral injuries and meniscal tears, if present, that required debridement rather than repair. More rapid access to care might improve the prognosis of young patients with ACL and meniscal injuries with public insurance.

Characterization of patellar maltracking using dynamic kinematic CT imaging in patients with patellar instability.

PURPOSE: Little has been reported on the relationship between patellar maltracking and instability. Patellar maltracking has been subjectively described with the "J sign" but is difficult to assess objectively using traditional imaging. Dynamic kinematic computed tomography (DKCT) allows dynamic assessment of the patellofemoral joint. DKCT was used to visualize and quantify patellar maltracking patterns, and severity of maltracking was correlated with the presence or absence of patellar instability symptoms. METHODS: Seventy-six knees in 38 patients were analysed using DKCT. Maltracking was defined as deviation of the patella from the trajectory of the trochlear groove and was characterized by patellar bisect offset, which was measured at 10° intervals of knee flexion during active flexion and extension. Bisect offset measurements were grouped by number of quadrants of maximum lateral patellar motion, with one, two, and three quadrants corresponding to 75-99, 100-125, and >125 %, respectively. Patellar instability symptoms were correlated with maltracking severity. RESULTS: Two knees were excluded because of poor imaging quality. Fifty of 74 knees had patellar instability, and 13 patients had bilateral symptoms. Of these, four (8 %) had normal tracking patterns; 41 (82 %) had increased lateral translation in extension, which we termed the J-sign pattern; 4 (8 %) had persistent lateralization of the patella throughout range of motion; and 1 had increased lateral translation in flexion. In knees with the J-sign pattern, degree of maltracking was graded by severity: J1 (n = 24), J2 (n = 19), and J3 (n = 15). The sensitivities of J-sign grades in predicting patellar instability symptoms were 50 % (J1), 80 % (J2), and 93 % (J3) (p < 0.01). There were significant differences in sensitivity between knees with no J sign or J1 versus J2 or J3 (p = 0.02). CONCLUSION: DKCT showed several patellar maltracking patterns in patients with patellar instability. A J-sign pattern with more than two quadrants of lateral translation correlated with the presence of patellar instability symptoms. Incorporation of this approach of objectively quantifying maltracking patterns is recommended in the evaluation of patellofemoral instability. LEVEL OF EVIDENCE: IV.

Calcific Tendinitis of the Gluteus Maximus in a Golfer.

Calcific tendinitis is a relatively rare condition in which calcium is inappropriately deposited in tendons, resulting in a local inflammatory reaction that can cause severe symptoms in certain cases. The cause of this disease process is not completely understood, although repetitive microtrauma likely plays a role in its development. Although the disorder most often involves the rotator cuff, it can affect other structures throughout the body, such as the tendons about the ankle and hip-including the rectus femoris and gluteus maximus. Nonoperative management typically involves using an anti-inflammatory medication and activity modification and can be augmented with formal physical therapy and modalities. Although nonoperative management provides adequate relief for many patients, sometimes operative debridement of the calcific deposit with or without repair of the involved tendon is required. The authors report an unusual case of calcific tendinitis of the gluteus maximus insertion in a golfer. The patient had tried nonoperative treatment for approximately 2 years with no real relief, and a recent exacerbation of the pain was significantly delaying his return to sport. Although plain radiographs did not show abnormalities, magnetic resonance imaging showed a calcific deposit in the insertion of the gluteus maximus tendon. After discussing further treatment options with the patient, the decision was made to remove the deposit and repair the insertion. He recovered completely and was able to return to play. The frequency, pathogenesis, and treatment of this condition are discussed in this case report, as well as the possible link to golf in this patient. [Orthopedics.2016; 39(5):e997-e1000.].

The Relationship Between Tibial Tuberosity-Trochlear Groove Distance and Abnormal Patellar Tracking in Patients With Unilateral Patellar Instability.

PURPOSE: To evaluate the role of tibial tuberosity-trochlear groove (TT-TG) distance in patellofemoral kinematics by retrospectively reviewing the dynamic computed tomography scans of patients with unilateral patellofemoral instability and comparing unstable and contralateral asymptomatic knees. METHODS: We reviewed all dynamic computed tomography scans obtained at one tertiary care hospital from 2008 through 2013 and identified 25 patients with a history of recurrent unilateral patellofemoral instability. During the scans, subjects performed active knee extension against gravity. Both knees were imaged simultaneously. Lateral patellar tilt (LPT) and bisect offset (BO) were measured to assess tracking. TT-TG distance was measured to assess alignment. Measurements were made in full extension, maximum flexion, and approximately 10° increments in between. The significance level was set at P < .05. RESULTS: LPT, BO, and TT-TG distance were highest in extension and decreased with flexion. Measurements were higher in symptomatic than in asymptomatic knees, with significant differences identified for LPT, BO, and TT-TG distance at 5° and 15° and for TT-TG distance at 25° and 35° (P < .05). TT-TG distance was associated with LPT and BO, with r(2) values in symptomatic knees of 0.55 for TT-TG distance and LPT and of 0.45 for TT-TG distance and BO. CONCLUSIONS: In patients with unilateral patellar instability, LPT, BO, and TT-TG distance are higher on the unstable side. An association exists between TT-TG distance and the tracking parameters studied, suggesting that TT-TG distance relates to patellar tracking, and a laterally positioned tibial tuberosity may predispose to instability episodes. LEVEL OF EVIDENCE: Level IV, diagnostic study.

Correlation Between Changes in Tibial Tuberosity-Trochlear Groove Distance and Patellar Position During Active Knee Extension on Dynamic Kinematic Computed Tomographic Imaging.

PURPOSE: The purpose of this study was to evaluate changes in tibial tuberosity-trochlear groove (TTTG) distance with knee flexion in patients with patellar instability and correlate it with patellar position. METHODS: Patients with symptomatic patellar instability underwent dynamic kinematic computed tomography (CT) during a cycle of knee extension from flexion. Knee flexion angles and corresponding TTTG distances, bisect offset, and patellar tilt were measured. Of the 51 knees, 37 had data available for interpolation between 5° and 30°. Results were interpolated to standardized intervals between 5° and 30° of knee flexion. Repeated-measures analysis (to identify differences between TTTG measurements at various knee flexion angles) and linear regression models (to assess for correlations between TTTG distance and bisect offset and between TTTG distance and patellar tilt) were used. RESULTS: Fifty-one symptomatic knees in 38 patients were available for analysis. Bisect offset and patellar tilt correlated significantly (P < .001) with TTTG distance over all flexion angles. Interpolated results for comparison resulted in 37 knees in which the mean TTTG distance of 17.2 ± 5.8 mm at 5° decreased to 15.5 ± 5.7, 13.0 ± 5.5, and 11.5 ± 4.9 mm at 10°, 20°, and 30° of knee flexion, respectively. Mean TTTG at 5° was 1.5 times greater than that at 30° (P < .001). At 5°, 70.3% (26 of 37) of knees had a TTTG distance of more than 15 mm; at 30°, only 24.3% (9 of 37) exceeded this threshold. CONCLUSIONS: Knee flexion angle during imaging is a critical factor when measuring TTTG distance to evaluate patellofemoral instability. We found that the mean TTTG distance varied by 5.7 mm between 5° and 30° of flexion in patients with symptomatic instability, although this relationship was not completely linear. Bisect offset and patellar tilt measurements mirrored this pattern, suggesting that TTTG distance influences patellar tracking in these patients. LEVEL OF EVIDENCE: Level IV, prognostic case series.

Imaging characteristics of contralateral asymptomatic patellofemoral joints in patients with unilateral instability.

PURPOSE: To test the hypothesis that in patients with unilateral patellofemoral instability ( PI patellofemoral instability ), the contralateral asymptomatic joints have abnormal morphology and imaging features of osteoarthritis ( OA osteoarthritis ) at four-dimensional ( 4D four-dimensional ) computed tomography (CT). MATERIALS AND METHODS: The institutional review board approved this HIPAA-compliant retrospective study. Informed consent was waived. Radiology records were reviewed to identify 25 patients (male-female ratio, 0.56; median age, 20 years; range, 13-43 years) with unilateral PI patellofemoral instability undergoing 4D four-dimensional CT and 25 age- and sex-matched control patients undergoing multidetector CT. Trochlear groove depth ( TGD trochlear groove depth ), tibial tuberosity-trochlear groove ( TT-TG tibial tuberosity-trochlear groove ) distance, and patellar height ratio ( PHR patellar height ratio ) were determined to compare morphology, and bisect offset ( BO bisect offset ) measurements were obtained to compare lateral displacement of the patella between the two groups by using the Wilcoxon rank-sum test. All images were interpreted by trained observers. Tracking patterns of the patellae were determined by obtaining BO bisect offset measurements at various flexion angles with 4D four-dimensional CT. RESULTS: In the contralateral asymptomatic joints, TGD trochlear groove depth (median, 3.0 mm; 95% confidence interval [ CI confidence interval ]: 2.5, 4.6; P < .0001), TT-TG tibial tuberosity-trochlear groove (median, 15 mm; 95% CI confidence interval : 12.7, 18; P = .008), PHR patellar height ratio (median, 1.17; 95% CI confidence interval : 1.09, 1.2; P = .002), and patellar lateral displacement ( BO bisect offset , 85%; 95% CI confidence interval : 76.2%, 98.2%; P < .0001) were different from measurements obtained in the control group: TGD trochlear groove depth median, 5.0 mm (95% CI confidence interval : 2.2, 7.6); TT-TG tibial tuberosity-trochlear groove median, 10.9 mm (95% CI confidence interval : 3.4, 20.7); PHR patellar height ratio median, 0.92 (95% CI confidence interval : 0.67, 1.36); and BO bisect offset median, 63% (95% CI confidence interval : 59%, 68.4%). OA osteoarthritis was detected in 40% of asymmetrical contralateral joints (10 of 25). By using 4D four-dimensional CT data, multiple regression analysis demonstrated that TGD trochlear groove depth (P = .026) and BO bisect offset measurements obtained at 30° of knee flexion (P = .047) had an association with the presence of OA osteoarthritis . CONCLUSION: Abnormal morphology and imaging features of OA osteoarthritis are relatively common in contralateral asymptomatic joints of young patients with unilateral PI patellofemoral instability .

Pediatric hand and wrist injuries.

In the last 40 years, childhood hand and wrist injuries have become progressively more common as children have become heavier and more active in high impact sports. The majority of children with such injuries do well, but treatment is not always straightforward. Distal radius fractures, scaphoid fractures, metacarpal and phalangeal fractures, nailbed injuries, and amputations are among the pediatric hand and wrist injuries most often seen by orthopedists. These are all discussed, with a focus on the most recent literature and areas of evolving controversy.

Trapezium trabecular morphology in carpometacarpal arthritis.

PURPOSE: In thumb carpometacarpal osteoarthritis, current evidence suggests that degenerative, bony remodeling primarily occurs within the trapezium. Nevertheless, the pathomechanics involved and the most common sites of wear remain controversial. Quantifying structural bone morphology characteristics with high-resolution computed tomography CT (micro-CT) infer regions of load transmission. Using micro-CT, we investigated whether predominant trabecular patterns exist in arthritic versus normal trapeziums. METHODS: We performed micro-CT analysis on 13 normal cadaveric trapeziums and 16 Eaton stage III to IV trapeziums. We computationally divided each specimen into 4 quadrants: volar-ulnar, volar-radial, dorsal-radial, and dorsal-ulnar. Measurements of trabecular bone morphologic parameters included bone volume ratio, connectivity, trabecular number, and trabecular thickness. Using analysis of variance with post hoc Bonferroni/Dunn correction, we compared osteoarthritic and normal specimen quadrant measurements. RESULTS: No significant difference existed in bone volume fraction between the osteoarthritic and normal specimens. Osteoarthritic trapeziums, however, demonstrated significantly higher trabecular number and connectivity than nonosteoarthritic trapeziums. Comparing the volar-ulnar quadrant of osteoarthritis and normal specimens collectively, this quadrant in both consistently possessed significantly higher bone volume fraction, trabecular number, and connectivity than the dorsal-radial and volar-radial quadrants. CONCLUSIONS: The significantly greater trabecular bone volume, thickness, and connectivity in the volar-ulnar quadrant compared with the dorsal-radial and dorsal-ulnar quadrants provides evidence that the greatest compressive loads at the first carpometacarpal joint occur at the volar-ulnar quadrant of the trapezium, representing a consistently affected region of wear in both normal and arthritic states. CLINICAL RELEVANCE: These findings suggest that trapezial trabecular morphology undergoes pathologic alteration. This provides indirect evidence that changes in load transmission occur with thumb carpometacarpal joint arthritis development.

The benefits of implant removal from the foot and ankle.

BACKGROUND: Following successful orthopaedic surgical procedures, implant removal is generally not necessary or recommended. However, patients with pain related to implants may benefit from this elective procedure. The foot and ankle may be more symptomatic from retained implants because of weight-bearing activities, shoe wear, and limited soft-tissue cushioning. In such cases, implant removal may provide good and reliable relief of symptoms. METHODS: A prospective study of sixty-nine patients who underwent elective removal of symptomatic implants from the foot and ankle was undertaken to evaluate the patients' pain experience. The short-form McGill pain questionnaire was administered preoperatively and six weeks postoperatively. Postoperatively, patients were also asked whether they would repeat the procedure and whether they were satisfied with the results. RESULTS: Patients reported significantly less pain following the procedure, with the average rating of pain on the visual analog scale (VAS) decreasing from 3.06 to 0.88 and the average rating of present pain intensity decreasing from 2.03 to 0.58 (p < 0.05 for both). Sixty-five percent of the patients reported no pain on either measure at six weeks postoperatively. Preoperative pain was correlated with postoperative pain (r = 0.24 and p < 0.05 for VAS, and r = 0.16 and p > 0.05 for present pain intensity).With the small sample size, preoperative and postoperative pain did not show a significant difference on the basis of implant location or patient age or sex. Ninety-four percent of patients said they would repeat the procedure under the same circumstances, and 91% of patients were satisfied with the results. CONCLUSIONS: Following successful orthopaedic surgical procedures, removal of implants causing symptoms can result in pain relief and a high rate of patient satisfaction. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

CD 9 and vimentin distinguish clear cell from chromophobe renal cell carcinoma.

BACKGROUND: Clear cell renal cell carcinoma (ccRCC) and chromophobe renal cell carcinoma (chRCC) can usually be distinguished by histologic characteristics. Occasionally, diagnosis proves challenging and diagnostic difficulty will likely increase as needle biopsies of renal lesions become more common. METHODS: To identify markers that aid in differentiating ccRCC from chRCC, we used gene expression profiles to identify candidate markers that correlate with histology. 39 antisera and antibodies, including 35 for transcripts identified from gene expression profiling, were evaluated. Promising markers were tested on a tissue microarray (TMA) containing 428 renal neoplasms. Strength of staining of each core on the TMA was formally scored and the distribution of staining across different types of renal neoplasms was analyzed. RESULTS: Based on results from initial immunohistochemical staining of multitissue titer arrays, 23 of the antisera and antibodies were selected for staining of the TMA. For 7 of these markers, strength of staining of each core on the TMA was formally scored. Vimentin (positive in ccRCC) and CD9 (positive in chRCC) best distinguished ccRCC from chRCC. The combination of vimentin negativity and CD9 positivity was found to distinguish chRCC from ccRCC with a sensitivity of 100.0% and a specificity of 95.2%. CONCLUSION: Based on gene expression analysis, we identify CD9 and vimentin as candidate markers for distinguishing between ccRCC and chRCC. In difficult cases and particularly when the amount of diagnostic tissue is limited, vimentin and CD9 staining could serve as a useful adjunct in the differential diagnosis of ccRCC and chRCC.