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Biomedical subjects

Bernard R Bach

Publications and source records attributed to Bernard R Bach.

At least 19 recordsLinked to original sources
PubMed2006

The effect of cyclic loading on rotated bone-tendon-bone anterior cruciate ligament graft constructs.

BACKGROUND: Single-incision anterior cruciate ligament reconstruction with a bone-patellar tendon-bone construct is commonly performed with 180 degrees rotation of the graft. It has been hypothesized that further rotation of the graft to 540 degrees can effectively shorten the graft to address graft length-tunnel mismatch. Initial biomechanical failure characteristics of rotated constructs have been reported, but cyclic loading of tendons has not been performed. HYPOTHESIS: Graft rotation affects the biomechanical properties of the construct. STUDY DESIGN: Controlled laboratory study. METHODS: Thirty-five bone-patellar tendon-bone composite porcine right knee specimens were randomized into 3 groups and were externally rotated to 0 degrees , 180 degrees , or 540 degrees . Each group was then cyclically loaded in an artificial synovial fluid medium between 50 and 250 N for 5,000 cycles, loaded between 50 and 500 N for an additional 5,000 cycles, and finally subjected to load-to-failure testing. RESULTS: Graft rotation shortened constructs by 1.7 +/- 0.8 mm at 180 degrees of rotation and 7.6 +/- 2.0 mm at 540 degrees of rotation (P < .01). There was a statistically significant increase in strain during cyclic loading at 540 degrees . No significant differences in maximum load, yield stress, yield strain, or modulus of elasticity were detected in single-cycle load-to-failure testing after cyclic loading. CONCLUSION: Rotation of bone-patellar tendon-bone constructs to 540 degrees predictably shortens the effective graft length at the expense of increased strain with cyclic loading at stresses equivalent to walking and running. CLINICAL RELEVANCE: Although rotation to 540 degrees potentially addresses graft length-tunnel mismatch, further clinical evaluation is required to evaluate the impact of increased strain on knee laxity and to determine the effects of physiologic loading of rotated bone-patellar tendon-bone constructs in vivo.

Animals↗
PubMed2006

Chondrolysis after continuous intra-articular bupivacaine infusion: an experimental model investigating chondrotoxicity in the rabbit shoulder.

PURPOSE: Postoperative pain pumps are increasingly used to deliver a continuous infusion of local anesthetic into the surgical wound or the joint. Recently, there have been concerns that the use of such devices may be associated with chondrotoxicity and even cases of chondrolysis in the shoulder. An experimental model is presented that investigates potential chondrotoxic effects of a continuous intra-articular infusion of bupivacaine in the rabbit shoulder. METHODS: We divided 30 rabbits into 3 groups that received continuous infusions of either saline solution, bupivacaine, or bupivacaine with epinephrine into the glenohumeral joint over a period of 48 hours. Animals were killed after 1 week, and osteochondral and synovial samples from the glenohumeral joint underwent analyses with confocal microscopy for live/dead cell assay, metabolic sulfate uptake assessment, and conventional histologic analysis. RESULTS: Infusion of bupivacaine with epinephrine and without epinephrine decreased sulfate uptake by 56% (P = .009) and 50% (P = .02), respectively, when compared with saline solution; cell viability decreased by 20% (P = .08) and 32% (P = .02), respectively. Histologic analysis yielded significantly worse scores for bupivacaine infusion with epinephrine (P = .004) and without epinephrine (P = .02). The results for bupivacaine with or without epinephrine were not significantly different. CONCLUSIONS: Continuous intra-articular infusion of bupivacaine with and without epinephrine led to significant histopathologic and metabolic changes in articular cartilage. CLINICAL RELEVANCE: Bupivacaine showed profound chondrotoxic effects in an experimental model that closely followed the current clinical application of postoperative pain pumps. The results caution against the use of such devices in applications for smaller joints with minimal clearance or dilution as a result of hematoma, where continuous exposure of cartilage to bupivacaine is expected.

Analgesia, Patient-Controlled↗
PubMed2006

Evaluation of the medial elbow in the throwing athlete.

The valgus forces generated by throwing athletes can cause injuries and permanently damage the medial elbow structures. Clinicians must have a clear understanding of the ulnar collateral ligament complex and the associated medial elbow structures at risk in these athletes. Taking a detailed history, conducting a physical examination, and obtaining imaging studies will aid in making the correct diagnosis and giving these injuries the appropriate treatment. Pain around the medial elbow is of concern to throwing athletes, coaches, and medical staff. Valgus forces generated by the throwing motion add considerable stress to the medial elbow structures and thus potentially cause injury. Baseball players, particularly pitchers, are most often affected, but athletes participating in sports such as football, volleyball, water polo, tennis, and javelin throwing can also be affected.

Athletic Injuries↗
PubMed2005

Preliminary clinical results of two techniques for addressing graft tunnel mismatch in endoscopic anterior cruciate ligament reconstruction.

This study reports the initial clinical results of 540 degrees of graft rotation or free tibial bone block to address graft tunnel mismatch in endoscopic anterior cruciate ligament (ACL) reconstruction. The operative reports of patients who underwent endoscopic ACL reconstruction between 1999 and 2001 were reviewed. Nine of 11 patients treated with a free tibial bone block and 14 of 17 patients treated with 540 degrees of graft rotation were evaluated. Mean follow-up was 20 months (range: 13-40 months) for the bone block group and 34 months (range: 18-48 months) for the 540 degrees group. There were statistically significant improvements in physical examination test results postoperatively, and only one patient in the 540 degrees group had a grade one positive pivot shift test. KT-1000 arthrometer testing demonstrated a statistically significant decrease in manual maximum and side-to-side differences at final follow-up. Mean Lysholm and Noyes sports function scores were excellent or good for all patients. One patient required reoperation for flexion contracture, one patient required an arthroscopic irrigation and debridement for a minor infection, and one patient required arthroscopic subtotal medial meniscectomy for failed meniscal repair. No difference was noted between these results and previous results of patients undergoing conventional endoscopic ACL reconstruction. These results demonstrate graft rotation and free bone block techniques are effective in addressing graft tunnel mismatch in endoscopic ACL reconstruction.

Adolescent↗
PubMed2005

Arthroscopic meniscal repair: analysis of treatment failures.

The rationale for meniscal repair is based on the importance of the meniscus in overall knee function and stability as well as the inferior results seen with meniscectomy. The high success rate usually seen with arthroscopic meniscal repair has made it the treatment of choice for peripheral meniscal tears. This study reviewed the records of patients who have failed meniscal repair surgery to gain greater understanding of the factors that may predispose a patient to a failed outcome. From 1987 to 2002, three hundred meniscal repairs were performed (203 medial and 97 lateral). Thirty-seven patients had failed meniscal repairs. Records were available for 33 (89%) patients. The mean patient age was 25 years (range: 13-48 years) at the time of meniscal injury. The average initial tear size was 2.7 cm with a mean rim width of 2.3 mm. Eighty-eight percent occurred in ACL tears. The average time interval from initial repair to the recurrence of symptoms was 34 months. Patients who were older at the time of meniscal repair failed significantly later than those patients who were younger at the time of repair. With age stratification, those patients who were aged > or =29 years at time of meniscal repair failed at an average of 23 months. In contrast, patients who were aged > or =30 years at the time of repair failed at an average of 53 months. Larger initial tears failed significantly sooner than smaller tears. Initial tears with larger rim widths demonstrated a trend toward shorter time to failure. Patients who underwent combined ligament reconstruction with meniscal repair failed at an average of 37 months. Deficient ACLs that were treated with isolated meniscal repairs (ACL intact) failed at an average of 16 months.

Adolescent↗
PubMed2005

Primary anterior cruciate ligament reconstruction using fresh-frozen, nonirradiated patellar tendon allograft: minimum 2-year follow-up.

BACKGROUND: There are conflicting reports of allograft performance, immune response, tissue incorporation, and rerupture rates when used for anterior cruciate ligament reconstruction. PURPOSE: To evaluate the clinical outcome of a fresh-frozen, nonirradiated, patellar tendon allograft for primary anterior cruciate ligament reconstruction surgery. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Patients who underwent endoscopic primary anterior cruciate ligament reconstruction with allograft tissue a minimum of 2 years ago were evaluated with physical examinations, the KT-1000 arthrometer, functional testing, radiographic evaluation, subjective assessment, and outcomes tools. RESULTS: Fifty-nine patients (60 knees) were evaluated at an average of 51 months after surgery. Ninety-four percent of patients were mostly or completely satisfied. A negative pivot shift test result was noted in 90% of subjects. The KT-1000 arthrometer side-to-side differences were < or =3 mm in 95% of patients, and no patient exceeded 5 mm. The mean International Knee Documentation Committee score was 78 (SD = 19), and the mean Lysholm score was 82 (SD = 17). There were no clinical symptoms consistent with graft rejection or infection. Radiographic evaluation demonstrated infrequent significant tunnel widening. CONCLUSIONS: Use of a fresh-frozen, nonirradiated allograft for primary reconstruction of the anterior cruciate ligament is a successful procedure both subjectively and functionally for restoring stability in patients selected for allograft reconstruction. In the patients selected for this surgical procedure, clinical, arthrometric stability testing, and subjective satisfaction were comparable to our previously published cohort studies using patellar tendon autograft at similar postoperative follow-up.

Adolescent↗
PubMed2005

The effect of radiofrequency energy on nonweight-bearing areas of bone following shoulder and knee arthroscopy.

This prospective randomized clinical trial evaluated whether the use of radiofrequency energy (RFE) devices for soft-tissue ablation and coagulation cause thermal injury to bone. Fifty patients underwent one of three treatment modalities: electrocautery, monopolar RFE, or bipolar RFE. Preoperative and postoperative magnetic resonance imaging was compared to evaluate for evidence of osteonecrosis. Postoperative MRI of all patients did not reveal any osteonecrosis or subchondral edema. These findings indicate electrocautery, monopolar RFE, and bipolar RFE devices can be used safely for soft-tissue blation and hemostasis.

Acromion↗
PubMed2004

Open Bankart repair versus arthroscopic repair with transglenoid sutures or bioabsorbable tacks for Recurrent Anterior instability of the shoulder: a meta-analysis.

BACKGROUND: In published comparative studies, it remains unknown if arthroscopic techniques for performing Bankart repair for anterior shoulder instability equal the success of open repair. HYPOTHESIS: The current literature supports a lower rate of recurrent instability after open Bankart repair compared to arthroscopic repair with bioabsorbable tacks or transglenoid sutures. STUDY DESIGN: Meta-analysis. METHODS: A Medline search identified all randomized controlled trials or cohort studies that directly compared open repair to arthroscopic techniques of Bankart repair for traumatic, unilateral, recurrent anterior instability. Data collected from each study included patient demographics, surgical technique, rehabilitation, outcome, and complications. RESULTS: Six studies met all inclusion criteria. There were 172 patients in the arthroscopic group (90 patients with transglenoid sutures, 77 patients with arthroscopic tacks, and 5 patients with suture anchors) and 156 patients in the open group. The groups were similar in demographic characteristics. When comparing the arthroscopic to the open group, there was a significantly higher rate of recurrent dislocation (12.6% vs 3.4%; P = .01) and total recurrence (recurrent dislocation or subluxation) (20.3% vs 10.3%; P = .01). In addition, there was a higher proportion of patients with an excellent or good postoperative Rowe score in the open group (88%) than in the arthroscopic group (71%) (P = .01). CONCLUSIONS: Arthroscopic Bankart repair using transglenoid sutures or bioabsorbable tacks results in a higher rate of recurrence of instability compared to open techniques. Studies comparing open repair to newer arthroscopic techniques using suture anchor fixation and capsular plication are necessary.

Absorbable Implants↗
PubMed2004

An accessory portal for posterior cruciate ligament tibial insertion visualization.

Posterior cruciate ligament (PCL) reconstruction is infrequently performed, technically challenging, and has less predictable results compared with its anterior cruciate ligament (ACL) counterpart. Creation of a transtibial tunnel has been associated with catastrophic neurovascular complications, as well as tunnel malpositioning. This technical note reports the use of the femoral PCL tunnel to visually access the posterior slope for tibial tunnel creation. This technique modification allows concurrent placement of instruments through an inferomedial and/or posteromedial portal to facilitate PCL insertional debridement, placement of the tibial aimer, and creation of the tunnel. We feel that this technical modification provides superior visualization of this anatomic area.

Arthroscopes↗
PubMed2004

Revision anterior cruciate ligament reconstruction with nonirradiated fresh-frozen patellar tendon allograft.

PURPOSE: To evaluate the effectiveness of a revision anterior cruciate ligament reconstruction with nonirradiated patellar tendon allograft used to salvage a failed index patellar tendon autograft procedure. TYPE OF STUDY: Retrospective case series with minimum 2-year follow-up. METHODS: Between 1993 and 1999, 39 patients underwent a revision reconstruction. Clinical, radiographic, arthrometric, and functional evaluations were performed. The Tegner, Lysholm, Noyes, Knee Injury and Osteoarthritis Outcome Score (KOOS), International Knee Documentation Committee (IKDC), and SF-12 rating scales were used. Statistical analysis was conducted with our Biostatistics Department. RESULTS: Thirty-two of 38 patients (84%) were personally evaluated. The mean patient age was 28 years (range, 16 to 57 years); the mean follow-up was 4.8 years (range, 2.1 to 12.1 years). After revision, there were significant improvements in the Lachman and pivot-shift test results: 87% had a grade 0/1+ Lachman and a 0/1+ pivot-shift. However, 25% had a grade 1+ pivot-shift. Postoperatively, KT-1000 testing revealed that 84% had a maximum manual side-to-side difference of < or =3 mm and 6% had >5 mm. Functional testing revealed a mean 4% difference in side-to-side comparisons for a single-leg hop for distance and time, as well as vertical jump. The mean results of Noyes sports function (72), Lysholm (75), Tegner (6.3), KOOS sports activity scale (67), SF-12 physical component (48), SF-12 mental component (55), and IKDC (71) were obtained. The Noyes sports activity score showed a significant improvement from 55 preoperatively to 70 at follow-up. Subjectively, 87% of patients indicated that they were completely or mostly satisfied with the surgical outcome. One patient required another revision. CONCLUSIONS: The 2- to 11-year follow-up showed that the results of revision ACL reconstruction with a nonirradiated patellar tendon allograft were less favorable than those of a primary anterior cruciate ligament reconstruction, with a lower subjective satisfaction level and a higher percentage of patients with grade 1+ or higher pivot-shift results. However, when compared with previously published reports, our results were comparable and underscore that revision anterior cruciate ligament surgery should be approached with tempered enthusiasm and careful preoperative counseling, and considered as a salvage procedure. LEVEL OF EVIDENCE: Level IV.

Adolescent↗
PubMed2004

Postoperative pain management after anterior cruciate ligament reconstruction.

This study compared pain and its management in four groups of patients after anterior cruciate ligament (ACL) surgery. Group 1 consisted of primary ACL reconstruction, group 2 primary ACL reconstruction with meniscal repair, group 3 primary ACL reconstruction with meniscal resection, and group 4 revision ACL reconstruction with patellar tendon allograft. Each patient was instructed to record his or her pain level on a visual analog pain scale (VAS) prior to the procedure and for 7 days postoperatively. All patients received a prescribed narcotic to be taken orally as needed every 4-6 hours. Each patient was instructed to taper its use and supplement with non-narcotic as symptoms allowed. The VAS score for all groups peaked at postoperative day 1 and remained elevated at postoperative day 2. At postoperative day 7, the VAS scores for groups 1, 2, and 3 began to show signs of further decline, whereas group 4 persisted at postoperative day 5 levels. A general trend of decreasing narcotic use over time and increasing non-narcotic use was noted in each group; however, these findings were not statistically significant. All four groups had nearly identical mean VAS scores and corresponding narcotic use for each postoperative day despite the differing levels of complexity of surgical intervention in each group.

Adult↗
PubMed2004

Adolescent ACL injury: treatment considerations.

Anterior cruciate ligament (ACL) injury in a skeletally immature patient presents unique treatment challenges. In many cases, conservative treatment with bracing and physical therapy fails, resulting in recurrent instability, pain, swelling, and meniscal and chondral injury. The goal of surgical reconstruction is to recreate ACL stability without causing growth plate arrest, leg-length discrepancy, or angular deformity. Patient characteristics such as skeletal age, Tanner stage, onset of menses, family member height, growth spurt, recent change in foot size, and growth charts can help the surgeon approximate the degree of skeletal maturity and aid in selecting the timing and safest type of reconstruction. Numerous surgical techniques, ranging from an extra-articular reconstruction to intra-articular graft passage without physeal violation to standard transtibial and transfemoral tunnel placement with physeal violation, have been popularized. The majority of existing studies are retrospective case series, describing a particular author's specific technique experience. This article reviews the basic science and clinical literature, presents a treatment algorithm, and provides several case studies.

Adolescent↗