Selective cell proliferation can be controlled with CPC particle coatings.

To develop implantable, engineered, cartilage constructs supported by a scaffold, techniques to encourage rapid tissue growth into, and on the scaffold are essential. Preliminary studies indicated that human endothelial cells proliferated at different rates on different calcium phosphate ceramic (CPC) particles. Judicious selection of particles may encourage specific cell proliferation, leading to an ordered growth of tissues for angiogenesis, osteogenesis, and chondrogenesis. The goal of this study was to identify CPC surfaces that encourage bone and vascular cell growth, and other surfaces that support chondrocyte growth while inhibiting proliferation of vascular cells. Differences in bone and vascular cell proliferation were observed when using epoxy without embedded CPCs to encourage bone cells, and when three CPCs were tested, which encouraged vascular cell proliferation. One of these (CPC 7) also substantially depressed cartilage cell proliferation. Only one small-diameter crystalline CPC (CPC 2) supported rapid chondrocyte proliferation, and maintained the cartilage cell phenotype.

Anterior cruciate ligament reconstruction in the immature athlete: long-term results of intra-articular reconstruction.

From 1986-1992, a total of 21 ACL reconstructions were completed in 20 skeletally immature athletes with an average age of 13.7 years (range: 11.8-15.6 years). Fifteen patients underwent operative reconstruction with hamstring tendons with wide open physes and 6 patients with bone-patellar tendon-bone (BPTB). All grafts were anatomically placed through transphyseal bone tunnels in the femur and tibia. Nineteen of 20 patients (20 of 21 reconstructions) returned for follow-up at an average of 34 months (range: 17-89 months). All patients had reached skeletal maturity at follow-up. No patient had limb-length discrepancy >1 cm postoperatively. No change in tibiofemoral alignment was noted (average 4.5 versus 4.25, P=.69). Modified Lysholm score was 93/95, and 19 of 20 athletes returned to preinjury level sports activity. Ligament laxity side-to-side difference was <3 mm in 16 patients, 3-6 mm in 2 patients, and >6 mm in 2 patients. One patient developed recurrent symptomatic laxity and was lost to follow-up. Two late graft ruptures (1 hamstring and 1 BPTB graft) occurred after major reinjury during sports. In this group of patients, ACL reconstruction through bone tunnels successfully eliminated instability although the failure rate, including late graft ruptures, was higher than that usually reported for adults. No limb length or angular deformity developed as a result of the transphyseal tunnels.

A comparison of outcomes at 2 to 6 years after acute and chronic anterior cruciate ligament reconstructions using hamstring tendon grafts.

PURPOSE: To compare short- to intermediate-term outcomes of patients in whom an acute or chronic anterior cruciate ligament (ACL) reconstruction was performed with a hamstring tendon graft. TYPE OF STUDY: A consecutive case series of patients who had 2-incision, arthroscopically assisted ACL reconstructions with a triple-strand hamstring tendon graft was retrospectively evaluated. METHODS: A total of 120 patients were evaluated at a mean of 44 months. The Tegner Activity Scale, individual components of the Cincinnati Knee Rating System, and the modified Lysholm Score were administered to all patients. A total of 93 patients (78%) returned for examination, instrumented ligament laxity testing, radiographs, isokinetic strength testing, and completion of the IKDC Standard Knee Ligament Evaluation Form. Data from patients undergoing reconstructions for acute and chronic ACL deficiencies were compared. The acute group was defined as reconstruction within 6 weeks of injury without recurrent episodes of instability. RESULTS: At surgery, significantly more (P <.05) cartilage abnormalities and partial medial menisectomies were found in the chronic group. At final follow-up, no significant differences (P >.05) were found between the acute and chronic groups for instrumented laxity, muscle strength, knee motion, or sports activity level. The acute group scored significantly higher (P <.05) on the Lysholm scale, Cincinnati Function scale, IKDC subjective assessment, and IKDC rating for pain at follow-up. The final IKDC grade resulted in significantly more (P =.039) normal knees for the acute group; however, 94.1% of acute and 92.9% of chronic knees were graded normal or nearly normal. CONCLUSIONS: Hamstring tendons are an excellent graft choice for ACL reconstruction in both acute and chronic injuries. According to the strict IKDC rating system, greater than 90% of all patients can be expected to have a normal or nearly normal knee at short- to intermediate-term follow-up; however, the chronic group will have fewer patients with a rating of normal.

Natural history of a hamstring tendon autograft used for anterior cruciate ligament reconstruction in a sheep model.

The purpose of this study was to describe the histologic structure of the intraarticular segment of a semitendinosus tendon autograft used for anterior cruciate ligament reconstruction over the first year after surgery. We performed an anterior cruciate ligament reconstruction in a single hindlimb of 11 sheep using a doubled semitendinosus tendon autograft secured to the femur with an endoscopic button and polyester tape and to the tibia with sutures tied around a screw. The histologic structure of the intraarticular segment of the graft at 4, 8, 12, 24, and 52 weeks after surgery was compared with that of the normal semitendinosus tendon and anterior cruciate ligament. The random collagen fiber orientation progressed to a longitudinal orientation from the peripheral to the central areas of the graft over the initial 12 weeks after surgery. A uniform sinusoidal crimp pattern similar to that seen in the normal anterior cruciate ligament was identified under polarized light in nearly one-half of each graft by 24 weeks. Further maturation was noted at 52 weeks. Graft necrosis was not evident at any time period. This study showed that semitendinosus tendon autografts transform into a histologic structure similar to that of the normal anterior cruciate ligament over the initial year after surgery, as has been described for patellar tendon grafts.

Treatment of partial meniscal tears identified during anterior cruciate ligament reconstruction with limited synovial abrasion.

SUMMARY: This is a retrospective review of the results of 40 patients with 44 partial stable meniscal tears who were treated with parameniscal synovial abrasion at the time of anterior cruciate ligament reconstruction. There were 19 medial meniscal (MM) tears and 25 lateral meniscal (LM) tears. Meniscal tear morphology included 33 single longitudinal tears (18 MM, 15 LM), 10 double longitudinal tears (1 MM, 9 LM), and 1 radial tear (LM). All 44 tears were located in the posterior horn or posterior junction of the meniscus. Rim width was 3 mm in 15 tears. In this study, failure was defined as a symptomatic meniscal tear requiring subsequent surgery. The overall failure rate at an average follow-up of 3.3 years was 11% (5 of 44). Four failures occurred in the MM (21% of total MM tears) and 1 failure occurred in the LM (4% of total LM tears). The median time to failure was 12 months with 3 of 5 failures occurring secondary to a significant reinjury. We looked at the effect of 8 factors on overall failure rate. Although statistical validity was not established in this small patient population, we did observe a higher failure rate for stable MM tears. Our study supports the small amount of literature that shows a high clinical success rate with observation of stable LM tears identified at the time of anterior cruciate ligament reconstruction. However, the much higher failure rate of stable MM tears raises concern. This difference is explained by biomechanical and clinical studies showing that the MM develops higher stresses than the LM with loading. Based on this work, we believe that stable longitudinal MM tears have a higher propensity to fail over time by propagation of the tear and are better managed with meniscal repair.

Tendon-to-bone healing of a semitendinosus tendon autograft used for ACL reconstruction in a sheep model.

Anterior cruciate ligament (ACL) reconstruction was performed in a single hind limb of 30 sheep using a doubled semitendinosus tendon graft. Three additional animals were used as controls. Histologic and biomechanical analysis was performed from 4-52 weeks postoperatively. Perpendicular collagen fibers were found connecting the tendon graft to the bone tunnels at 8 weeks. These fibers were seen circumferentially at 12 weeks. By 24 weeks, the bone tunnel was well-defined, and no further changes were observed at 52 weeks. Tendon incorporation within the femoral and tibial tunnels was similar at each interval. Although the small sample size did not permit statistical testing, the reconstruction strength was similar up to 12 weeks (15%-19% of controls). This increased at 24 (28%) and 52 (40%) weeks. The stiffness primarily increased from 4-8 weeks (18%-39%) and 24-52 weeks (52%-82%). Up to 12 weeks, failures occurred by graft pull-out from the bone tunnel. All 24- and 52-week specimens ruptured through the intra-articular portion of the graft, further indicating sufficient graft incorporation within the bone tunnels.

Healing of articular cartilage: a review.

Currently, there is no one human technique that stands out as being better than another. The results of curettement or microfracture remain as good as anything else that is available. The healing in these defects seems to be as good as those that are achieved with osteochondral tissue graft or with chondrocyte culture techniques. The controlled prospective treatment of cartilage defects that compares these techniques to traditional methods has not been done.

Strength of ACL reconstructions using semitendinosus tendon grafts.

PURPOSE: Patellar tendon autografts have been considered by many as the gold standard for intraarticular reconstruction of the anterior cruciate ligament (ACL). Hamstring tendon grafts are being used increasingly, however there are few studies focusing on their mechanical properties. The objectives of the present study are to determine the strength of a semitendinosus graft at various postoperative periods. METHODS: In Part I of the study, a looped semitendinosus graft was used to reconstruct the ACL in five frozen human cadaver knees with a simulated endoscopic technique. The immediate post-operative strength was determined by loading the knees of failure using a mechanical testing system. In Part II the effects of graft maturation and incorporation were considered. A similar graft was used to reconstruct the ACL in twelve ewe sheep. Their knees were harvested and tested at four, eight, and twelve weeks postoperatively. RESULTS: The mean maximum strength and stiffness of the cadaveric reconstructions were 352 N and 8.18 N/mm, respectively. All failures occurred at the fixation sites. The average strength of the sheep reconstructions was similar at four, eight, and twelve weeks (376 N. 415 N. and 323 N. respectively). The stiffness increased from 21.1 N/mm at four weeks to 46.7 N/mm at eight weeks and then remained the same. The failures occurred primarily by tendon pull-out of the femoral tunnel at four, eight and twelve weeks. CONCLUSIONS: Graft pull-out from the femoral tunnel implies incomplete tendon incorporation during the initial three months post-operatively. Activities which place high loads on the graft should be avoided during this period. Additionally, the mechanical properties of this hamstring graft reconstruction are similar to those reported for patellar tendon grafts in other animal models.

Analysis of a semitendinosus autograft in a rabbit model.

The purpose of this study was to evaluate the histologic and biomechanical changes that occur between 12 and 52 weeks in an intraarticular, semitendinosus autograft placed through tibial and femoral drill holes in a rabbit model. The results of this study show that, in this rabbit model, the soft tissue graft maintained its biologic fixation in the osseous tunnel when stressed to failure at 1 year. The bony fixation occurred by the formation of an indirect tendon insertion, and this formation was complete by 26 weeks. At 52 weeks, large differences persisted in the strength and stiffness of the graft compared with the normal semitendinosus tendon and anterior cruciate ligament. Based on the results of this study, we support a cautious approach in returning patients to early full activity, including sports, after anterior cruciate ligament reconstruction with a semitendinosus autograft.

Arthroscopic subacromial decompression: two- to seven-year follow-up.

Arthroscopic subacromial decompression (ASD) was performed in 88 patients (90 shoulders) with stage II or early III impingement syndrome of the shoulder unresponsive to nonoperative treatment. The purpose of this retrospective study was to evaluate the follow-up an average of 41 months (range 24 to 82 months) after surgery. We wished to compare results in (1) patients with and without rotator cuff tears, (2) in athletes and nonathletes, and (3) in throwers and nonthrowers. Patients were evaluated by (1) Neer's Criteria for Satisfactory Result, (2) the UCLA Shoulder RAting Scale, (3) the Shoulder and Elbow Surgeons Rating Scale, (4) a detailed questionnaire, and (5) patient satisfaction. In the follow-up group (n = 90), 80% met Neer's criteria for satisfactory result; 94% had satisfactory results by the UCLA Shoulder Scale; 95% had a satisfactory result by the Shoulder and Elbow Society Scale; and 93% of shoulder patients expressed satisfaction at follow-up. There were no statistically significant differences in function between the group without rotator cuff tear (n = 47) and the group with rotator cuff tear (n = 43). Satisfactory results were obtained in 68% of throwing athletes and in 90% of nonthrowing athletes (P < .05) by the Neer Rating, whereas only 50% of competitive baseball and softball pitchers had satisfactory results. Out impression is that ASD is an acceptable alternative to open anterior acromioplasty with comparable results for the treatment of the impingement lesion. There were no differences in result in patients who had a partial rotator cuff tear and those who had no tear.(ABSTRACT TRUNCATED AT 250 WORDS)

The effects of anabolic steroids on rat tendon. An ultrastructural, biomechanical, and biochemical analysis.

Forty-eight male rats were randomly separated into four groups: a control group, a group treated with anabolic steroids, a group treated with daily exercise, and a group treated with both steroids and exercise. At 6 weeks, biomechanical, ultrastructural, and biochemical testing was performed on the Achilles tendons of half of the rats in each group. The remaining rats continued in the experimental protocol, but steroid administration was discontinued. Similar testing was then performed on the remaining rats at 12 weeks. Testing showed anabolic steroids produced a stiffer tendon that absorbs less energy and fails with less elongation; tendon strength was unaffected. Effects were entirely reversible on discontinuation of the steroids. Light microscopic analysis revealed no changes in the appearance of the fibrils. No change in fibril diameter or shape was noted on electron microscopic analysis. Biochemical testing revealed no change in qualitative immunofluorescence staining with Type III collagen or fibronectin. Abuse of anabolic steroids is a widespread problem among competitive athletes; consequently, complications after their use are seen with increasing frequency. Knowledge of the effects of these drugs on tendon and the musculotendinous unit may prove helpful in counseling athletes who use anabolic steroids.

An analysis of rotator cuff repair.

Fifty-four patients who had surgery to repair a chronic rotator cuff tear (54 shoulders) were followed for an average of 25.9 months (range, 16 to 43). Forty-nine of 54 patients had at least 20 months of followup. The average age of the male patients (N = 37) was 52 (range, 24 to 80) and of the female patients (N = 17) was 56 (range, 38 to 72). All of these patients received a functional evaluation based on the Shoulder and Elbow Surgery Society classification system. Forty-eight patients had an individual examination and 33 patients had an isokinetic strength evaluation. There were 43 patients (80%) with a satisfactory functional result and 11 (20%) with an unsatisfactory result. Unsatisfactory results were associated with large and massive tears and decreased postoperative range of motion. Good functional results were obtained by open repair and subacromial decompression for rotator cuff tear. Arthroscopic evaluation and treatment did not affect the functional outcome, but it did increase costs by about $2000 per patient. Arthroscopy is useful to define tear size, which may affect the surgical approach, but the arthroscopic treatment of glenohumeral problems did not alter the functional result. The routine use of arthroscopy before rotator cuff repair is costly, not effective, and therefore not recommended.

An analysis of autograft fixation after anterior cruciate ligament reconstruction in a rabbit model.

Fixation and incorporation of a tendon implanted within the bone pose theoretical as well as practical concerns for the surgeon who treats instability problems of the knee. Understanding the physiology involved in graft-bone incorporation is necessary for the appropriate rehabilitation of patients who undergo anterior cruciate ligament surgery. The purpose of the study was to examine the histologic and biomechanical changes of a semitendinosus autograft reconstruction of the anterior cruciate ligament in a rabbit model at the graft-bone tunnel interface in the femur. The results indicate that by 3 weeks, failure of the bone-graft-bone or construction is through the intraarticular portion of the graft, not as a result of pullout from the bone tunnel. Graft fixation of the bone tunnel occurs by an intertwining of graft and connective tissue and anchoring of connective tissue to bone by collagenous fibers and bone formation in the tunnels. The collagenous fibers have the appearance of the Sharpey's fibers seen in an indirect tendon insertion.