Richard A. Marder

Prospective evaluation of arthroscopically assisted anterior cruciate ligament reconstruction Patellar tendon versus semitendinosus and gracilis tendons

Eighty consecutive patients with chronic laxity due to a torn ACL underwent arthroscopically assisted recon struction with either autogenous patellar tendon or doubled semitendinosus and gracilis tendons. Recon structions were performed on a one-to-one alternating basis. Preoperatively, no significant differences be tween the two groups were noted with respect to age, sex, level of activity, and degree of laxity (chi square analysis). A standard rehabilitation regimen was used for all patients after surgery including immediate pas sive knee extension, early stationary cycling, protected weightbearing for 6 weeks, avoidance of resisted ter minal knee extension until 6 months, and return to activity at 10 to 12 months postoperatively. Seventy-two patients were evaluated at a minimum of 24 months postoperatively (range, 24 to 40 months). No significant differences were noted between groups with respect to subjective complaints, functional level, or objective laxity evaluation, including KT-1000 meas urements. Seventeen of 72 patients (24%) experienced anterior knee pain after ACL reconstruction. Overall, 46 of 72 patients (64%) returned to their preinjury level of activity. Mean KT-1000 scores were 1.6 ± 1.4 mm for the patellar tendon group and 1.9 ± 1.3 mm for the semitendinosus and gracilis tendons group. This study did find a statistically significant weakness in peak hamstrings torque at 60 deg/sec when recon struction was performed with double-looped semiten dinosus and gracilis tendons.

Increase in outpatient knee arthroscopy in the United States: a comparison of National Surveys of Ambulatory Surgery, 1996 and 2006.

BACKGROUND This study was proposed to investigate the changes in the utilization of knee arthroscopy in an ambulatory setting over the past decade in the United States as well as its implications. METHODS The National Survey of Ambulatory Surgery, last carried out in 1996, was conducted again in 2006 by the Centers for Disease Control and Prevention. We analyzed the cases with procedure coding indicative of knee arthroscopy or anterior cruciate ligament reconstruction. To produce estimates for all arthroscopic procedures on the knee in an ambulatory setting in the United States for each year, we performed a design-based statistical analysis. RESULTS The number of arthroscopic procedures on the knee increased 49% between 1996 and 2006. While the number of arthroscopic procedures for knee injury had dramatically increased, arthroscopic procedures for knee osteoarthritis had decreased. In 1996, knee arthroscopies performed in freestanding ambulatory surgery centers comprised only 15% of all orthopaedic procedures, but the proportion increased to 51% in 2006. There was a large increase in knee arthroscopy among middle-aged patients regardless of sex. In 2006, >99% of arthroscopic procedures on the knee were in an outpatient setting. Approximately 984,607 arthroscopic procedures on the knee (95% confidence interval, 895,999 to 1,073,215) were performed in an outpatient setting in 2006. Among those, 127,446 procedures (95% confidence interval, 95,124 to 159,768) were for anterior cruciate ligament reconstruction. Nearly 500,000 arthroscopic procedures were performed for medial or lateral meniscal tears. CONCLUSIONS This study revealed that the knee arthroscopy rate in the United States was more than twofold higher than in England or Ontario, Canada, in 2006. Our study found that nearly half of the knee arthroscopic procedures were performed for meniscal tears. Meniscal damage, detected by magnetic resonance imaging, is commonly assumed to be the source of pain and symptoms. Further study is imperative to better define the symptoms, physical findings, and radiographic findings that are predictive of successful arthroscopic treatment.

The Rotator Cuff Opposes Superior Translation of the Humeral Head

To determine the influence of rotator cuff muscle activity on humeral head migration relative to the glenoid during active arm elevation we studied five fresh cadaveric shoulders. The shoulder girdles were mounted in an apparatus that simulated contraction of the deltoid and rotator cuff muscles while maintaining the normal scapulothoracic relationship. The arms were abducted using four different configurations of simulated muscle activity: deltoid alone; deltoid and supraspinatus; del toid, infraspinatus, teres minor, and subscapularis; and deltoid, supraspinatus, infraspinatus, teres minor, and subscapularis. For each simulated muscle configura tion the vertical position of the humeral head in relation to the glenoid was determined at 30°, 60°, 90°, and 120° of abduction using digitized anteroposterior radio graphs. Both muscle activity and abduction angle sig nificantly influenced the glenohumeral relationship. With simulated activity of the entire rotator cuff, the geo metric center of the humeral head was centered in the glenoid at 30° but had moved 1.5 mm superiorly by 120°. Abduction without the subscapularis, infraspina tus, and teres minor muscles caused significant supe riorly directed shifts in humeral head position as did ab duction using only the deltoid muscle. These results support the possible use of selective strengthening ex ercises for the infraspinatus, teres minor, and sub scapularis muscles in treatment of the impingement syndrome.

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

To evaluate the occurrence of emergency department (ED) visits due to humerus fractures in the US.

Primary repair of patellar tendon rupture without augmentation

Repair of patellar tendon ruptures has often relied on cerclage augmentation and prolonged immobilization in extension. We are reporting our experience with avulsion injuries as well as midsubstance ruptures, both treated with primary repair without augmentation, allowing early mobilization in the athlete less than 40 years of age. Repairs were performed to allow knee flexion to more than 60°. Rehabilitation was performed with heel slides, allowing flexion to 45° for the first 3 weeks, increasing to 90° at 3 to 6 weeks, and thereafter without restriction. An accelerated weightbearing and muscle strengthening program was adopted. At a mean follow-up of 2.6 years (range, 20 to 61 months), 12 patients had returned to their previous levels of activity. No loss of extension or extensor lag was noted; mean flexion loss was 5°. Patellofemoral symptoms and signs were present in five patients, but activity was limited in only two. Mean peak torque at 60 deg/sec was 92% (range, 73% to 105%). Mean Lysholm score was 94 2.5 points. Primary repair with immediate, protected range of motion resulted in uniformly excellent results and obviated the need for manipulation or subsequent hardware removal.

Effects of partial patellectomy and reattachment of the patellar tendon on patellofemoral contact areas and pressures

We used a previously reported experimental method to measure patellofemoral contact areas and pressures in four pairs of human cadaveric knees before and after a partial patellectomy. The knee joints were loaded by application of a flexion moment, which was resisted by the extension moment of the quadriceps mechanism. Patellofemoral contact was measured with the use of pressure-sensitive film, at 30, 60, and 90 degrees of flexion of the knee. Partial patellectomy decreased the patellofemoral contact area and increased pressure. We observed alterations in the patterns of contact, including a proximal shift in patellofemoral contact, after partial patellectomy. An anterior reattachment of the patellar tendon significantly minimized the effects of 20 and 40 per cent patellectomies (p < 0.05). After a 60 per cent patellectomy, patellofemoral contact was altered markedly, with the contact area reduced to less than 50 per cent of the control values regardless of the position of the patellar tendon reattachment.

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.

Patellar strain and patellofemoral contact after bone-patellar tendon-bone harvest for anterior cruciate ligament reconstruction

OBJECTIVE To characterize the morbific consequences of harvesting a patellar tendon graft for use in reconstructing the anterior cruciate ligament (ACL) of the knee, specifically, (1) to measure changes in patellar strain and patellofemoral contact due to graft harvest, (2) to evaluate the ability of bone-grafting the patellar defect to mitigate these effects, and (3) to characterize failure of the extensor mechanism after harvest of a patellar tendon graft. DESIGN Twenty-two cadaver knee joints were tested before and after harvest of a patellar tendon graft and after filling the patellar defect with polymethylmethacrylate to simulate a healed bone graft, Knees were positioned in 30 degrees, 60 degrees, and 90 degrees flexion and loaded while measuring axial strain in the anterior patella and patellofemoral contact. Knees were then loaded to failure. RESULTS Harvest of the graft produced increases in axial strain at all flexion angles. Filling the defect restored axial strain to normal values. Patellofemoral contact in the presence of a defect, either filled or empty, was not different from contact for intact patellae. Most knees failed by transpatellar fracture; mean extension moment at failure was 112.8Nm. The best predictors of failure were age and gender. CONCLUSION Patients undergoing ACL reconstruction with a patellar tendon graft are at increased risk of anterior knee pain and disruption of the extensor mechanism. Bone-grafting the patellar defect created by graft harvest can reduce these risks. Our findings underscore the importance of carefully controlled rehabilitation and suggest that if an accelerated program of rehabilitation is anticipated, the patellar defect should be bone-grafted. Older patients, particularly women, are at increased risk of catastrophic failure of the knee extensor mechanism after ACL reconstruction using patellar tendon graft.

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.

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