Biomedical subjects

L M Galatz

Publications and source records attributed to L M Galatz.

7 recordsLinked to original sources

PubMed2006

Nicotine delays tendon-to-bone healing in a rat shoulder model.

BACKGROUND: Many studies have shown that nicotine negatively impacts fracture healing and bone fusion processes. However, very little is known about its effect on tendon and ligament healing. The goal of the present study was to evaluate the effect of nicotine on tendon-to-bone healing. METHODS: Supraspinatus tendons in both shoulders of seventy-two rats were transected and repaired to the humeral head. Osmotic pumps were implanted subcutaneously, and nicotine or saline solution was delivered for ten, twenty-eight, or fifty-six days. Cell morphology was evaluated with use of histologic sections. Cells were counted, and proliferating cell nuclear antigen (PCNA) immunohistochemistry was performed to assess cellular proliferation. In situ hybridization was performed to measure type-I collagen mRNA expression. Biomechanical and geometric properties were assessed. RESULTS: Inflammation persisted longer in the nicotine group than in the saline solution group. Cellular proliferation was higher in the saline solution group than in the nicotine group at the early time-points. Type-I collagen expression was higher in the saline solution group at twenty-eight days. Mechanical properties increased over time in both groups. Maximum stress was significantly lower in the nicotine group than in the saline solution group at ten days. Maximum force was significantly lower in the nicotine group than in the saline solution group at twenty-eight days. Maximum force was significantly higher in the nicotine group than in the saline solution group at fifty-six days. Stiffness was not different between the groups at any time-point. CONCLUSIONS: Nicotine caused a delay in tendon-to-bone healing in a rat rotator cuff animal model. Mechanical properties increased over time in both groups, but the properties in the nicotine group lagged behind those in the saline solution group. Chronic inflammation and decreased cell proliferation may partly explain the inferior biomechanical properties in the nicotine group as compared with the saline solution group. CLINICAL RELEVANCE: Failure of rotator cuff repair is a major clinical problem. The adverse effect of nicotine on rotator cuff healing noted in this clinically appropriate animal model may be an important clinical consideration.

Animals↗

PubMed2005

Delayed repair of tendon to bone injuries leads to decreased biomechanical properties and bone loss.

INTRODUCTION: Repair of the torn rotator cuff tendon is a common procedure performed in the shoulder. In the clinical setting, a significant delay between rotator cuff tear and subsequent repair often exists. The purpose of this study was to investigate the biomechanical properties and bone density of the tendon to bone repair site after acute and delayed repair. METHODS: The supraspinatus tendons in bilateral shoulders of 60 rats were transected from the bone. In the acute group, the tendons were immediately repaired with suture. In the delayed group, the tendons were allowed to retract and repaired in a second procedure after a 3-week delay. Cross sectional area and biomechanical properties were evaluated. Bone density of the humeral head was assessed using peripheral quantitative computed tomography. Histologic sections were obtained and examined. RESULTS: At 10 days the repair tissue displayed vascular and fibroblast proliferation accompanied by predominantly mononuclear infiltrate. At 28 days the inflammatory process gradually decreased. No significant histologic differences were noted between the acute and delayed repair specimens. Cross-sectional area was higher in the delayed group at the early time points (44% at 10 days and 31% at 28 days). Viscoelastic properties were greater in the acute group at the early time points and significantly less at the latest time point, compared to the delayed group. Bone density was markedly decreased (8% and 12%, 28 and 56 days respectively) in the delay group. DISCUSSION: Inferior rotator cuff healing was demonstrated when there was a delay between injury and repair. Viscoelastic properties of the acute repairs were increased compared to the delayed group at 10 days, indicating tendon stiffening during the 3-week delay before repair. Viscoelastic properties of the acute repairs were decreased compared to the delayed group at 56 days indicating deterioration of properties over time in the delayed group. The deterioration in properties in the delayed group coincide with bone density decreases in the greater tuberosity. These results indicate that bone loss may a significant factor in poor healing.

Animals↗

PubMed2001

Prospective longitudinal analysis of postoperative shoulder function : a ten-year follow-up study of full-thickness rotator cuff tears.

BACKGROUND: Rotator cuff repair is associated with good short or mid-term results, but to date there have been no long-term functional outcome studies demonstrating durability of results over time. In most long-term studies, the results have been compared with those of historical controls or with those of other, short-term follow-up studies. The purpose of the present prospective study was to evaluate short and long-term shoulder function after surgical repair in a single population of patients in order to follow changes over time. METHODS: Thirty-three patients underwent surgery, performed by one surgeon, for the treatment of a chronic, symptomatic, full-thickness rotator cuff defect. Data were obtained from questionnaires and physical examinations preoperatively, at two years, and at ten years. Identical standardized pain and function questionnaires were used and clinical evaluation was performed in a consistent fashion at all time-periods. The activity level, Constant score, level of disability, shoulder function score, and patient's subjective rating of the outcome were determined at the time of the final follow-up and compared with the same parameters at the two-year follow-up examination in order to determine if early results change with time. RESULTS: At the ten-year follow-up examination, there was no change in the raw Constant score determined at the two-year examination. When the Constant score was normalized for expected age-related changes, the percentage of patients who had a satisfactory result at ten years was even greater than the percentage at two years. Activity level decreased significantly over the time-period (p = 0.005). At the final follow-up examination, twelve patients worked at the same occupation as they had when the two-year examination was performed, two worked at a less strenuous occupation, and the remaining patients were retired. Only two patients retired because of problems related to the shoulder. The level of disability decreased over the study period, and there was a small improvement in the patients' self-assessment shoulder function score. The patients' subjective assessment of the outcome remained unchanged. CONCLUSIONS: The results of open rotator cuff repair for chronic tears do not deteriorate with time (ten years). The level of disability decreases, presumably because of a concurrent decrease in the activity level and in the demand on the shoulder as the patient ages. It is important to consider age-related changes when assessing the final outcome.

Adult↗

PubMed2001

Arthroscopic rotator cuff repair: transition from mini-open to all-arthroscopic.

Rotator cuff repair is one of the most common surgical procedures done in the shoulder. Traditionally, repair has required an open incision with release of a portion of the deltoid from the acromion. In the past decade, an arthroscopically-assisted, mini-open approach has gained popularity. This has been facilitated by advances in the use of arthroscopy. This trend toward a more minimally invasive approach has continued as arthroscopic techniques continue to improve and advance. An all-arthroscopic approach recently has been used for rotator cuff repairs. The arthroscopic approach offers several advantages including smaller incisions, easy access to the glenohumeral joint for treatment of intraarticular diseases, less soft tissue dissection, and less potential harm to the deltoid. The purpose of the current study is to discuss recent advances in arthroscopic and mini-open rotator cuff repair techniques and to highlight the technical aspects of the mini-open procedures that are important in making the transition to an allarthroscopic rotator cuff repair.

Arthroscopy↗

PubMed2000

Management of surgical neck nonunions.

A surgical neck nonunion is a seriously debilitating complication of a proximal humerus fracture. Patients have virtually no functional use of their shoulders and experience pain. Successful treatment is reliable in relief of pain and potentially can restore function. The diagnosis is not difficult, however, a CT scan may be necessary to identify tuberosity or head-splitting fractures. Successful treatment for these nonunions is difficult but gratifying because the percent improvement is immense.

Aged↗

PubMed1997

Biceps activity during shoulder motion: an electromyographic analysis.

Electromyographic responses in 44 shoulders from 30 subjects were examined. Fourteen shoulders from 13 patients had documented rotator cuff tears. The remaining volunteers had normal cuff integrity by history and examination. Electromyographic responses were recorded from the long head of the biceps, brachioradialis (elbow control), and from the supraspinatus (shoulder control). Elbow related biceps activity was minimized by using a brace locked in neutral forearm rotation and 100 degrees flexion. Analysis of normal and rotator cuff deficient data was performed in a masked fashion and electromyographic activity normalized as a percent of maximal muscle contraction during 10 shoulder motions based on the scapular plane. Normal shoulders in all ranges of active motion exhibited significant supraspinatus activity (20%-50% maximum muscle contraction). The response followed patterns expected for a shoulder stabilizer. In contrast, with every normal shoulder, biceps and brachioradialis activity remained insignificant (1.7%-3.6% maximum muscle contraction) and did not follow a patterned response. In patients with rotator cuff tears, biceps activity remained low (1.6%-4.4% maximum muscle contraction). As opposed to previous studies using electromyography about the shoulder, this trial examined shoulder specific biceps activity by relaxing the elbow. No significant biceps activity was observed in any shoulder, including patients with rotator cuff tears. Given these findings, any function of the long head of the biceps in shoulder motion does not involve active contractions.

Adult↗

PubMedDate not supplied

Anatomic evaluation of the subcoracoid pectoralis major transfer in human cadavers.

Subcoracoid transfer of the pectoralis major has recently been described as a reconstruction for subscapularis insufficiency. The purpose of this study was to examine the surgically relevant anatomy of this transfer. The importance of understanding this anatomy was recently highlighted to us following our encounter with musculocutaneous neuropraxia in 2 patients after transfer of the entire pectoralis major, one deep to the musculocutaneous nerve. Dissections were performed on 20 fresh, whole human cadavers in which the entire pectoralis major muscle, medial and lateral pectoral nerves, and musculocutaneous nerve were explored and quantified. The relationship between the pectoralis major and the conjoined tendon was studied in situ and after simulated transfers. The medial and lateral pectoral nerves were located far medial to the pectoralis major tendon insertion and appeared to be safe from injury as long as surgical dissection remained lateral to the pectoris minor and less than 8.5 cm from the humeral insertion. Transfer of the pectoralis major superficial to the musculocutaneous nerve created less tension than transfer deep to the musculocutaneous nerve. Because proximal innervation of the coracobrachialis and short head of the biceps is not an uncommon occurrence, a split pectoralis major transfer, release of the proximal musculocutaneous branches, or debulking of the pectoralis major muscle belly may be required in some instances to prevent tension on the nerve. Because of the variability and location of the musculocutaneous nerve, it should always be visualized operatively. Transfer of the pectoralis major tendon lateral to the biceps tendon appeared to best restore the muscle length-tension relationship.

Aged↗