Peter R. Kurzweil

A comparison of patellar tendon autograft and allograft used for anterior cruciate ligament reconstruction in the goat model

Similar-sized patellar tendon autografts and fresh-fro zen allografts were used to reconstruct the anterior cruciate ligament of one knee in 40 female goats. Evaluations of the reconstructions and contralateral controls at the 6-week and 6-month postoperative pe riods included anterior-posterior translation, mechanical properties determined during tensile failure tests, meas urement of cross-sectional area, histology, collagen fibril size and area distribution, and associated articular cartilage degenerative changes. Six months after anterior cruciate ligament recon struction, the autografts demonstrated a smaller in crease in anterior-posterior displacement, values of maximum force to failure two times greater, a significant increase in cross-sectional area, a more rapid loss of large-diameter collagen fibrils, and an increased density and number of small-diameter collagen fibrils compared to the allografts. Clinical significance . More surgeons are allowing their patients to return to running and sports 6 months after anterior cruciate ligament reconstruction. While the structural and material properties of autografts and allografts at time zero are similar, in the goat model during the first 6 months they differ. The allografts demonstrate a greater decrease in their implantation structural properties, a slower rate of biologic incorpo ration, and the prolonged presence of an inflammatory response. At 6 months the autograft demonstrates a more robust biologic response, improved stability, and increased strength to failure values.

Survival of cells after intra-articular transplantation of fresh allografts of the patellar and anterior cruciate ligaments. DNA-probe analysis in a goat model.

The fate of donor cells in fresh allografts of the patellar and anterior cruciate ligaments was assessed after transplantation of the allografts as substitutes for the anterior cruciate ligament in goats. DNA-probe analysis was used to distinguish between the DNA of individual goats. Donor DNA was completely replaced by recipient DNA in both the transplanted patellar and anterior cruciate ligaments within a four-week period. Simultaneous full-thickness skin transplants in the same animals were not rejected during the interval of rapid loss of donor DNA from the allografts. The absence of rejection of the skin grafts at the one-week interval suggests that no pre-existing antibody associated with an immune reaction was responsible for the rapid loss of DNA in the allografts.

Repair of Horizontal Meniscus Tears: A Systematic Review

PURPOSE Despite the well-documented advantages of meniscal repair over meniscectomy, horizontal cleavage tears (HCTs) are often not repaired. Reported reasons include difficulty performing the repair, potential suture failure due to mechanical stresses, and poor healing rates. In addition, many surgeons have the perception that debriding the tear until the superior and inferior laminae are stable results in a good clinical outcome. Furthermore, many of the tears occur in patients who are older than the generally accepted indicated age for repair and may also have a degenerative component, making them potentially less likely to benefit from repair. This review was performed to evaluate the published outcomes of HCT repairs and test the hypothesis that surgically repaired HCTs have an unacceptably low rate of success. METHODS A systematic search of the PubMed and Embase databases was performed in December 2013 to identify studies in which meniscal HCTs were repaired. Inclusion criteria for the analysis were English language, reference to a patient with an HCT repaired by any method, and a report of at least 1 postoperative outcome. For the purposes of this review, a failed outcome was defined as the need for reoperation. RESULTS More than 16,000 abstracts were returned in the search. From these abstracts, we identified 210 articles for further review, of which 9 met the inclusion criteria. A total of 98 repairs of horizontal tears were evaluated in these studies. By use of reoperation as the criterion for treatment failure, 77 of the repairs were successful, for an overall success rate of 77.8%. CONCLUSIONS The literature does not support the hypothesis that surgically repaired HCTs have an unacceptably low rate of success. Rather, our results show that existing studies of repaired HCTs show a comparable success rate to repairs of other types of meniscal tears. LEVEL OF EVIDENCE Level IV, systematic review of Level IV studies.

Tibial interference screw removal following anterior cruciate ligament reconstruction

A small number of patients developed pain and tenderness at the tibial tunnel following anterior cruciate ligament reconstruction. Twenty-three knees in 22 patients underwent removal of the tibial interference screw. Ten knees had a preoperative flexion contracture and underwent a concomitant procedure to address the loss of motion at the time of hardware removal. In the 13 knees with full extension, the interval between ligament reconstruction and screw removal averaged 16 months. Eleven of these knees also underwent arthroscopy, but no intra-articular causes of pain were identified. Roentgenographic analysis showed protrusion of the interference screw above the tibial cortex in three cases. Follow-up after hardware removal averaged 2 years. Tibial tunnel tenderness resolved in 21 of 23 knees, including those of the two patients who underwent hardware removal alone. Although it cannot be stated with certainty that tibial interferences screws may cause pain, this review suggests an association. This is an uncommon problem and it is estimated to be a factor in less than 3% of the authors anterior cruciate ligament reconstructions. More common causes of knee pain should be sought before electing to remove the tibial interference screw.

ENDOSCOPIC ACL RECONSTRUCTION

The endoscopic technique offers the advantage of one incision and a femoral osseous tunnel trajectory that is more in line with the collagen fibers of the graft. Technically, it is more demanding to reproducibly obtain the interference fixation than using the two-incision technique. There is a tendency for screw and graft divergence in the femoral tunnel. The exact clinical significance of this screw and bone plug divergence has yet to be clarified. Surgeons must assess their ability to obtain the best results for the patient. There is a definite learning curve for the endoscopic technique. We believe that, with further advances in instrumentation, fixation, and alternative grafts, it will eventually be the approach of preference for ACL reconstructions.

Magnetic resonance imaging appearance of the shoulder after subacromial injection with corticosteroids can mimic a rotator cuff tear.

Subacromial injections have been used to treat rotator cuff problems. Previous studies have noted the difficulty in performing accurate injections into this area. In addition, one must also question the effects that misplaced corticosteroids could have on the surrounding tissues. In this case, a 51-year-old woman presented with several weeks of left shoulder pain and was diagnosed with rotator cuff tendonitis. After a subacromial injection with betamethasone and lidocaine, the patient noted 3 weeks of near complete pain relief, followed by a return of her symptoms. A magnetic resonance imaging scan obtained 7 weeks after the injection showed a full-thickness tear of the supraspinatus tendon. Five weeks later, the patient underwent arthroscopic evaluation of the shoulder and subacromial decompression. The rotator cuff tendons were noted to be intact and normal in appearance. The patient eventually had full resolution of her symptoms. Six months postoperatively, she underwent a new scan that showed a normal supraspinatus tendon. Apparently, the subacromial injection penetrated the anterior half of the supraspinatus tendon, causing a transient effect and signal change. One should use caution in the interpretation of magnetic resonance imaging scans of the shoulder soon after the injection of corticosteroids.

Editorial Commentary: Should I Order Prophylactic Antibiotics for My Next Knee Scope?

Postoperative infections are going to happen. The question of whether prophylactic antibiotics can lower the infection rate in routine knee arthroscopy is investigated. Although a large number of cases were included in the study, the results did not reach statistical significance. Nevertheless, a significant trend toward a lower incidence of deep infection was seen when antibiotics were given.

Meniscus Tear MRI Correlation

On MRI, the diagnostic criteria for a meniscus tear include increased signal contacting the articular surface of the meniscus or abnormal morphology. Bucket-handle tears are displaced longitudinal tears and may demonstrate a fragment in the notch, double PCL, double anterior horn, and truncated meniscal body on MRI. Longitudinal tears are usually traumatic, parallel to the circumference of the meniscus, and are often reparable. The displaced portions of horizontal flap tears may be easily missed on MRI and should be specifically sought in the medial recesses, the posterior intercondylar notch, and the popliteal hiatus.