Incidence and Time Course of Symptomatic Thromboembolic Outcomes After Lower Extremity Arthroscopic Surgery, Ankle Fracture Surgery, and Achilles Tendon Repair.

BACKGROUND: The incidence and time course of acute venous thromboembolism (VTE) after ambulatory surgery for lower extremity orthopaedic conditions is not well-defined. HYPOTHESIS: The purpose of this study was to analyze the incidence, the time course, and risk factors associated with clinically diagnosed acute deep vein thrombosis or pulmonary embolism within 3 months of surgery in patients undergoing specific operations for lower extremity injuries. METHODS: Patients undergoing arthroscopic procedures of the knee, ankle fracture surgery, Achilles tendon repair, and ankle arthroscopy from January 1, 2005, to December 31, 2010, were identified in the California Ambulatory Surgery database with linkage to hospital discharge data, emergency department data, and a death registry. Outcomes were acute VTE and death within 90 days. Time courses were compared using Kaplan-Meier analysis, and risk factors were analyzed using proportional hazard modeling. RESULTS: Analysis of data from 468,699 surgeries showed that the cumulative incidence of acute VTE was significantly higher after Achilles tendon repair (0.72%, P < 0.001) than ankle fracture surgery (0.33%), knee arthroscopy procedures (range, 0.29% to 0.41%), or ankle arthroscopy (0.24%). The time course of diagnosis of VTE was similar for all arthroscopic procedures (median postoperative day for diagnosis = 9 to 10; 80% by 22 to 36 days), whereas for Achilles tendon surgery, the time course was protracted (median postoperative day for diagnosis = 29 days; 80% by 51 days). Ninety-day mortality was low (<0.06%) after all procedures except ankle fracture (0.12%). Predictors of pulmonary embolism included age older than 60 years (HR, 3.1; 95% CI; 2.0 to 4.8, versus younger than 30 years), Achilles tendon repair (HR, 3.8; 95% CI; 2.8 to 5.3), and ankle fracture surgery (Hazard Ratio [HR], 2.1; 95% Confidence Interval [CI]; 1.5 to 2.8); Asian/Pacific Islander (HR, 0.3; 95% CI; 0.1 to 0.6) and Hispanic patients (HR, 0.5; 95% CI; 0.4 to 0.7) had significantly lower risk. DISCUSSION: The incidence and time course of onset of acute VTE after lower extremity orthopaedic surgeries varies significantly depending on the surgical procedure. These findings have implications regarding the use and duration of pharmacologic thromboprophylaxis.

Aging Decreases the Ultimate Tensile Strength of Bone-Patellar Tendon-Bone Allografts.

PURPOSE: The purpose of this study was to determine whether aging imparts a clinically significant effect on the (1) mechanism of graft failure and (2) structural, material, and viscoelastic properties of patellar tendon allografts by evaluating these properties in younger donors (≤30 years of age) and older donors (>50 years of age). METHODS: A total of 34 younger (≤30 years of age) and 34 older (>50 years of age) nonirradiated, whole bone-tendon-bone allografts were prepared for testing by isolating the central third of the patellar tendon using a double-bladed 10-mm width scalpel under a 10-N load to ensure uniformity of harvest. Bone blocks were potted in polymethylmethacrylate within custom molds. Tendon length and cross-sectional area were measured using an area micrometer. A mechanical loading system was used to precondition the grafts for 100 cycles with a load between 50 N and 250 N (1 Hz). A creep load (500 N) was then applied at a rate of 100 mm/min (10 minutes). Grafts were allowed to recover at 1 N (10 minutes), followed by pull-to-failure at a rate of 100% strain per second. Mechanisms of failure (midsubstance vs avulsion) were noted and the structural, material, and viscoelastic properties calculated and compared between groups. RESULTS: There were 33 (97%) midsubstance tears in the younger group and 28 (82%) in the older group (P = .034). Younger grafts showed greater ultimate load to failure (1,782 N [1,533, 2,032] vs 1,319 N [1,103, 1,533]) (P = .006) and ultimate tensile stress (37.4 MPa [32.4, 42.4] vs 27.5 MPa [22.9, 32.0]) (P = .006). There were no significant differences in displacement (P = .595), stiffness (P = .950), strain (P = .783), elastic modulus (P = .114), creep displacement (P = .881), and creep strain (P = .614). CONCLUSIONS: This in vitro study suggests that aging weakens the bone-tendon junction and decreases the ultimate tensile strength of patellar tendon allografts. However, aging did not affect the displacement, strain, stiffness, elastic modulus, creep displacement, or creep strain of patellar tendon allografts. CLINICAL RELEVANCE: Surgeons should be aware that patellar tendon allografts from donors >50 years of age have a lower ultimate tensile stress than donors ≤30 years of age.

Tears in the distal superficial medial collateral ligament: the wave sign and other associated MRI findings.

OBJECTIVE: To analyze the MRI characteristics of distal superficial medial collateral ligament (sMCL) tears and to identify features of tears displaced superficial to the pes anserinus (Stener-like lesion (SLL)). MATERIALS AND METHODS: Knee MRI examinations at four institutions were selected which showed tears of the sMCL located distal to the joint line. MRIs were evaluated for a SLL, a wavy contour to the sMCL, and the location of the proximal sMCL stump. Additional coexistent knee injuries were recorded. RESULTS: The study included 51 patients (mean age, 28 years [sd, 12]). A SLL was identified in 20 of 51 cases. The proximal stump margin was located significantly (p < 0.01) more distal and more medial with a SLL (mean = 33 mm [sd = 11 mm] and mean = 6.5 mm [sd = 2.5 mm], respectively), than without a SLL (mean = 19 mm [sd = 16 mm] and mean = 4.8 mm [sd = 2.4 mm], respectively). Medial compartment osseous injury was significantly (p < 0.05) more common with a SLL (75%) than without a SLL (42%). The frequency of concomitant injuries in the group (ACL tear, 82%; PCL tear, 22%; deep MCL tear, 61%; lateral compartment osseous injury, 94%) did not differ significantly between patients with and without a SLL. CONCLUSION: A distal sMCL tear should be considered when MRI depicts a wavy appearance of the sMCL. Distal sMCL tears have a frequent association with concomitant knee injuries, especially ACL tears and lateral femorotibial osseous injuries. A SLL is particularly important to recognize because of implications for treatment.

The medial epicondyle of the distal femur is the optimal location for MRI measurement of semitendinosus and gracilis tendon cross-sectional area.

PURPOSE: Graft diameter ≥ 8 mm reduces the risk of failure after anterior cruciate ligament reconstruction (ALCR) with hamstring tendon autograft. Pre-operative measurement of gracilis (GT) and semitendinosus (ST) cross-sectional area using MRI has been utilized but the optimal location for measurement is unknown. The main purpose of this study was to examine the cross-sectional areas of GT + ST at different locations and develop a model to predict whether a doubled hamstring graft of GT + ST will be of sufficient cross-sectional area for ACLR. METHODS: A retrospective review was performed of 154 patients who underwent primary ACLR using doubled hamstring autograft. Cross-sectional area measurements of GT + ST on pre-operative MRI axial images were made at three locations: medial epicondyle (ME), tibiofemoral joint line (TJL), and tibial physeal scar (TPS) and calculated the correlation of intra-operative graft size for each location using the Pearson's correlation coefficient. A receiver operating characteristic (ROC) established a threshold that would predict graft diameter ≥ 8 mm. RESULTS: Measurement of GT + ST at the ME had a stronger correlation (r = 0.389) to intra-operative graft diameter than measurements at the TJL (r = 0.256) or TPS (r = 0.240). The ROC indicated good predictive value for hamstring graft diameter ≥ 8 mm based on MRI measurement at the ME with the optimal threshold with the highest sensitivity and specificity as 18 mm2. CONCLUSION: Cross-sectional area measurement of GT + ST at the ME correlated most closely to intra-operative diameter of a doubled hamstring autograft compared to measurements at the TJL or the TPS. As graft diameter < 8 mm is correlated with higher failure rates of ACL surgery, the ability to pre-operatively predict graft diameter is clinically useful. LEVEL OF EVIDENCE: Level III, prognostic study.

MR Imaging of SLAP Lesions.

BACKGROUND: SLAP lesions of the shoulder are challenging to diagnose by clinical means alone. Interpretation of MR images requires knowledge of the normal appearance of the labrum, its anatomical variants, and the characteristic patterns of SLAP lesions. In general, high signal extending anterior and posterior to the biceps anchor is the hallmark of SLAP lesions. Common diagnostic criteria for a SLAP lesion by MR or MR arthrography include the following: presence of a laterally curved, high signal intensity in the labrum on a coronal image, multiple or branching lines of high signal intensity in the superior labrum on a coronal image, full-thickness detachment with irregularly marginated high signal intensity and/or separation >2 mm on conventional MRI or 3 mm on MR arthrography between the labrum and glenoid on a coronal image, and a paralabral cyst extending from the superior labrum. METHODS: MR diagnosis of SLAP tears may be improved with provocative maneuvers, such as longitudinal traction of the arm or positioning of the shoulder in abduction and external rotation during imaging. The use of intra-articular contrast distends the joint similar to what occurs during arthroscopy and forced diffusion under the labrum may improve the ability to detect SLAP lesions that might not be seen with standard MR. Improved diagnostic accuracy for SLAP tears is seen with 3-T compared with 1.5-T MR imaging, with or without intra-articular contrast material. CONCLUSION: Regardless of MR findings, however, physicians should be cautious when recommending surgery in the patient with a vague clinical picture. The patient's history, physical exam, and imaging evaluation all should be considered together in making the decision to proceed with surgery.

Stimulation of the superficial zone protein and lubrication in the articular cartilage by human platelet-rich plasma.

BACKGROUND: Platelet-rich plasma (PRP) contains high concentrations of autologous growth factors that originate from platelets. Intra-articular injections of PRP have the potential to ameliorate the symptoms of osteoarthritis in the knee. Superficial zone protein (SZP) is a boundary lubricant in articular cartilage and plays an important role in reducing friction and wear and therefore is critical in cartilage homeostasis. PURPOSE: To determine if PRP influences the production of SZP from human joint-derived cells and to evaluate the lubricating properties of PRP on normal bovine articular cartilage. STUDY DESIGN: Controlled laboratory study. METHODS: Cells were isolated from articular cartilage, synovium, and the anterior cruciate ligament (ACL) from 12 patients undergoing ACL reconstruction. The concentrations of SZP in PRP and culture media were measured by enzyme-linked immunosorbent assay. Cellular proliferation was quantified by determination of cell numbers. The lubrication properties of PRP from healthy volunteers on bovine articular cartilage were investigated using a pin-on-disk tribometer. RESULTS: In general, PRP stimulated proliferation in cells derived from articular cartilage, synovium, and ACL. It also significantly enhanced SZP secretion from synovium- and cartilage-derived cells. An unexpected finding was the presence of SZP in PRP (2.89 ± 1.23 µg/mL before activation and 3.02 ± 1.32 µg/mL after activation). In addition, under boundary mode conditions consisting of high loads and low sliding speeds, nonactivated and thrombin-activated PRP decreased the friction coefficient (µ = 0.012 and µ = 0.015, respectively) compared with saline (µ = 0.047, P < .004) and high molecular weight hyaluronan (µ = 0.080, P < .006). The friction coefficient of the cartilage with PRP was on par with that of synovial fluid. CONCLUSION: PRP significantly stimulates cell proliferation and SZP secretion by articular cartilage and synovium of the human knee joint. Furthermore, PRP contains endogenous SZP and, in a functional bioassay, lubricates bovine articular cartilage explants. CLINICAL RELEVANCE: These findings provide evidence to explain the biochemical and biomechanical mechanisms underlying the efficacy of PRP treatment for osteoarthritis or damage in the knee joint.

Magnetic resonance imaging of the postoperative meniscus: resection, repair, and replacement.

Meniscus surgery is common, and surgical indications and techniques continue to evolve. After highlighting relevant anatomy and emerging magnetic resonance (MR) imaging techniques, this article reviews the current indications and techniques used for meniscus surgery, evaluates the use of MR imaging protocols with and without arthrography, and focuses on MR imaging interpretation of the postoperative meniscus, with particular attention to clinical outcomes and diagnostic criteria.

Injection of the subacromial bursa in patients with rotator cuff syndrome: a prospective, randomized study comparing the effectiveness of different routes.

BACKGROUND: Rotator cuff syndrome is often treated with subacromial injection of corticosteroid and local anesthetic. It has not been established if the common injection routes of the bursa are equally accurate. METHODS: We conducted a prospective clinical trial involving seventy-five shoulders in seventy-five patients who were randomly assigned to receive a subacromial injection through an anterior, lateral, or posterior route with respect to the acromion. An experienced physician performed the injections, which contained radiopaque contrast medium, corticosteroid, and local anesthetic. After the injection, a musculoskeletal radiologist, blinded to the injection route, interpreted all of the radiographs. RESULTS: The rate of accuracy varied with the route of injection, with a rate of 56% for the posterior route, 84% for the anterior route, and 92% for the lateral route (p = 0.006; chi-square test). The accuracy of injection through the posterior route was significantly lower than that through either the anterior or the lateral route (p < 0.05 for both comparisons; Poisson regression). In addition, the accuracy of injection was significantly lower in females than in males (p < 0.006; chi-square test). Among males, no differences between the routes were noted (with accuracy rates of 89% for the posterior route, 92% for the anterior route, and 93% for the lateral route). Among females, however, the accuracy of injection was lower for the posterior route than for either the anterior or the lateral route (with accuracy rates of 38% for the posterior route, 77% for the anterior route, and 91% for the lateral route) (p < 0.05). CONCLUSIONS: The anterior and lateral routes of subacromial bursal injection were more accurate than the posterior route. The accuracy of subacromial bursal injection was significantly different between males and females, mainly because of a lower accuracy of bursal injection with use of the posterior route in females. The present study suggests that the posterior route is the least accurate method for injection of the subacromial bursa in females.

Epidemiology of humerus fractures in the United States: nationwide emergency department sample, 2008.

OBJECTIVE: To evaluate the occurrence of emergency department (ED) visits due to humerus fractures in the US. METHODS: We analyzed the 2008 Nationwide Emergency Department Sample, which contained approximately 28 million ED records. We identified the cases of interest using diagnostic codes for proximal, shaft, and distal humerus fractures. RESULTS: In 2008, approximately 370,000 ED visits in the US resulted from humerus fractures. Proximal humerus fractures were the most common, accounting for 50% of humerus fractures. The incidence rate of proximal humerus fractures followed the shape of an exponential function in the age groups 40-84 years for women (R(2) = 97.9%) and 60-89 years for men (R(2) = 98.2%). After the exponential increase in these age intervals, the growth rate of proximal humerus fracture slowed and eventually decreased. The peak occurrence of distal humerus fractures was in children ages 5-9 years; however, elderly women had an increased risk. As the baby boomer generation ages, unless fracture prevention programs improve, more than 490,000 ED visits due to humerus fractures are expected in 2030 when the youngest of the baby boomers turn age 65 years. CONCLUSION: Compared to epidemiologic studies in Japan and European countries, the incidence rates of humerus fractures are substantially higher in the US. The high incidence rate of humerus fractures in the expanding elderly population may contribute to the recent trend of rapid increase in shoulder arthroplasty in the US. Rigorous safety measures to reduce falls and improved preventive treatments of osteoporosis are needed.

Calcific tendonitis of the shoulder: is subacromial decompression in combination with removal of the calcific deposit beneficial?

HYPOTHESIS: We postulated that treatment of patients with calcific tendonitis of the supraspinatus tendon by debridement of the calcific deposit alone was comparable to treatment by debridement and concomitant subacromial decompression. MATERIALS AND METHODS: During a 10-year period, 50 consecutive patients with calcific tendonitis refractory to nonoperative measures were surgically treated by debridement (D) as an isolated procedure (25 patients) or by debridement and concomitant subacromial decompression (D+SAD; 25 patients), and the surgical groups were retrospectively compared. The main outcome of interest was the time to resumption of unrestricted activity without pain. An abbreviated version of disabilities of the Disabilities of Arm, Shoulder and Hand (QuickDASH) score and University of California-Los Angeles (UCLA) shoulder summary scores were compiled at a mean follow-up of 5 years (range, 2-10 years). RESULTS: Average time to return to activity without pain was significantly shorter for the D group compared with the D+SAD group (11 vs 18 weeks; P < .006). At the final evaluation, QuickDASH scores were equally low (group D, 6; group D + SAD, 11; P = .191), indicating that both treatment groups had high levels of function. The mean UCLA shoulder scores at final evaluation were 33 for both groups (P = .678). DISCUSSION: Patients treated by debridement of the calcific deposit and concomitant subacromial decompression required a longer time to return to unrestricted activity without pain. CONCLUSIONS: Debridement of a calcific deposit alone is a better surgical option to treat calcific tendonitis.

Arthroscopic microfracture of chondral defects of the knee: a comparison of two postoperative treatments.

PURPOSE: We hypothesized that the treatment of focal, full-thickness chondral defects by an identical method of arthroscopic microfracture but with different postoperative regimens would produce similar results. TYPE OF STUDY: Case control study, retrospective cohort. METHODS: Fifty patients treated over a 6-year period (1993 to 1999) with a focal, less than 2-cm 2 , full-thickness chondral defect of either the medial or lateral femoral condyle of the knee had arthroscopic surgery to debride loose adjacent cartilage flaps and abortive fibrocartilage from the crater in conjunction with microfracture of the subchondral plate using a hand awl. Postoperatively, 1 group was treated with non-weight bearing and continuous passive motion (CPM) for 6 weeks (group I), and the other group was allowed weight bearing as tolerated and did not use CPM (group II). Results of treatment were assessed by the Lysholm knee rating scale augmented by the Tegner method of activity evaluation. Results were analyzed by independent t test or chi-square test with significance assumed for P < .05. RESULTS: Forty-three of 50 patients were evaluated at a minimum of 2 years after surgery (mean, 4.2 years; range, 2 to 9 years). The mean age was 39.7 years (range, 16 to 66 years) and there were 19 female and 24 male patients. For group I, Lysholm scores were 37 preoperative, 81 postoperative, and Tegner scores were 3 and 6, respectively. Group II Lysholm scores were 33 preoperative, 85 postoperative, and Tegner scores 3 and 6, respectively. No significant differences between groups were noted. CONCLUSIONS: In relatively small full-thickness chondral defects of the femoral condyles treated by microfracture, this study found no differences in results comparing 2 rehabilitation regimens differing by weight-bearing status and use of CPM. LEVEL OF EVIDENCE: Level III, Case Control Study.