How Cigarette Smoking Weakens Bones

How Cigarette Smoking Weakens Bones

Almost 20 years after scientists first identified cigarette smoking as a risk factor for osteoporosis and bone fractures, a new study is shedding light on exactly how cigarette smoke weakens bones. The report, in ACS' Journal of Proteome Research, concludes that cigarette smoke makes people produce excessive amounts of two proteins that trigger a natural body process that breaks down bone.

Gary Guishan Xiao and colleagues point out that previous studies suggested toxins in cigarette smoke weakened bones by affecting the activity of osteoblasts, cells which build new bone, and osteoclasts, which resorb, or break down, old bone. Weakening of the bones, known as osteoporosis, can increase the risk of fractures and is a major cause of disability among older people. To shed light on how cigarette smoking weakens bones, the scientists analyzed differences in genetic activity in bone marrow cells of smokers and non-smokers.

They discovered that human smokers produce unusually large amounts of two proteins that foster production of bone-resorbing osteoclasts compared to non-smokers. Experiments with laboratory mice confirmed the finding.

A Multicenter Randomized Controlled Trial Comparing Single-Row with Double-Row Fixation in Arthroscopic Rotator Cuff Repair

The Journal of Bone &Joint Surgery | Article

Peter L.C. Lapner, MD, FRCSC¹; Elham Sabri, MSc²; Kawan Rakhra, MD, FRCSC¹; Sheila McRae, MSc³; Jeff Leiter, PhD³; Kimberly Bell, BA¹; Peter MacDonald, MD, FRCSC³

¹ Division of Orthopaedics (P.L.C.L. and K.B.), Department of Diagnostic Imaging (K.R.), The Ottawa Hospital, General Campus, 501 Smyth Road, W1648, Box 502, Ottawa, ON K1H 8L6, Canada. E-mail address for P.L.C. Lapner: plapner@toh.on.ca. E-mail address for K. Rakhra: krakhra@toh.on.ca. E-mail address for K. Bell: kibell@toh.on.ca
² Methods Centre, Clinical Epidemiology Program, Ottawa Hospital Research Institute, 501 Smyth Road, Box 208, Room W0590, Ottawa, ON K1H 8L6, Canada. E-mail address: esabri@ohri.ca
³ Pan Am Clinic, 75 Poseidon Bay, Winnipeg, MB R3M 3E4, Canada. E-mail address for S. McRae: smcrae@panamclinic.com. E-mail address for J. Leiter: jleiter@panamclinic.com. E-mail address for P. MacDonald: pmacdonald@panamclinic.com

Background:  Controversy exists regarding the optimal technique for arthroscopic rotator cuff repair. The purpose of this multicenter, randomized, double-blind controlled study was to compare the functional outcomes and healing rates after use of single-row and double-row suture techniques for repair of the rotator cuff.
Methods:  Ninety patients undergoing arthroscopic rotator cuff repair were randomized to receive either a single-row or a double-row repair. The primary objective was to compare the Western Ontario Rotator Cuff Index (WORC) score at twenty-four months. Secondary objectives included comparison of the Constant and American Shoulder and Elbow Surgeons (ASES) scores and strength between groups. Anatomical outcomes were assessed with magnetic resonance imaging (MRI) or ultrasonography to determine the postoperative healing rates.
Results:  Baseline demographic data including age (p = 0.29), sex (p = 0.68), affected side (p = 0.39), and rotator cuff tear size (p = 0.28) did not differ between groups. The WORC score did not differ significantly between groups at any time point (p = 0.48 at baseline, p = 0.089 at three months, p = 0.52 at six months, p = 0.83 at twelve months, and p = 0.60 at twenty-four months). The WORC score at each postoperative time point was significantly better than the baseline value. The Constant score, ASES score, and strength did not differ significantly between groups at any time point. Logistic regression analysis demonstrated that a smaller initial tear size and double-row fixation were associated with higher healing rates.
Conclusions:  No significant differences in functional or quality-of-life outcomes were identified between single-row and double-row fixation techniques. A smaller initial tear size and a double-row fixation technique were associated with higher healing rates as assessed with ultrasonography or MRI.
Level of Evidence:  Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Risk of hamstring autograft failure higher after ACL surgery in young patients | Orthopedics

Risk of hamstring autograft failure higher after ACL surgery in young patients | Orthopedics

Risk of hamstring autograft failure higher after ACL surgery in young patients

• July 19, 2012

BALTIMORE — ACL reconstruction with hamstring autografts demonstrate higher failure rates in patients aged 25 years or younger, but researchers found no statistically significant link between graft size or Tegner activity level and failure rate, according to study results presented here at the American Orthopaedic Society for Sports Medicine Annual Meeting 2012.

“Patients 25 and younger have a higher failure rate with ACL reconstruction through hamstring autograft,” Przemyslaw M. Kamien, MD, said during his presentation.

“Hamstring tendons remain a very popular choice for autograft ACL reconstruction,” he said, noting that lately smaller hamstring autograft sites, however, have been associated with higher early revision rates.

Kamien said he and his colleagues looked at 98 patients who underwent ACL reconstruction with a hamstring autograft between 2000 and 2007. Those studied represented all age groups and activity levels and had at least 2 years follow-up.

“The failure rate in patients 25 and younger was pretty high: 25%,” Kamien said. “The failure rate in patients older than 25 was only 6%. This difference is statistically significant.”

There were 15 ACL reconstructions that qualified as failures, with 12 of them occurring in patients aged 25 years or younger. When Kamien and colleagues analyzed failure rate vs. age, they found a statistically significant relationship between the two factors. Graft size and failure rate, however, did not display statistical significance in either the complete patient population or the patients aged less than 25 years. Tegner activity level also was not related to failure rate in either population.

“We failed to find statistical significance between the Tegner activity score and graft site with failure, and although our failure rates were higher in patients with smaller grafts, the difference did not reach statistical significance in our group,” Kamien said.

Reference:

Barret GR, Kamien PM, Replogle WH, Hydrick J. Age, graft size, and Tegner activity level as predictors of failure in anterior cruciate ligament reconstruction with hamstring autograph. Paper #19. Presented at the American Orthopaedic Society for Sports Medicine Annual Meeting 2012. July 12-15. Baltimore.

Award-winning study details simple method to make anatomic ACL femoral tunnels | Orthopedics

Award-winning study details simple method to make anatomic ACL femoral tunnels | Orthopedics

Award-winning study details simple method to make anatomic ACL femoral tunnels

• July 20, 2012

BALTIMORE — Research presented at the American Orthopaedic Society for Sports Medicine Annual Meeting 2012 yielded helpful guidelines for anatomic femoral tunnel placement in ACL reconstruction.

“We know that it is important to produce an anatomic femoral tunnel and an anatomic ACL, but there are two questions,” Alexander D. Davis, MD, said in his presentation of the work, for which he and his colleagues received the Aircast Award for Basic Science. “How do we find the anatomic femoral insertion and how do we create a tunnel at this location?”

Davis and colleagues removed the medial condyles from 12 fresh, frozen distal femurs. They dissected all the soft tissue except the ACL attachment and marked the centers of the ACL and its two bundles. The researchers than observed the femur in 90° flexion and marked the lowest point on the lateral wall of the notch. This point was then used as the starting point for a vertical line, against which Davis and colleagues measured the height of the ACL center and its composite bundles. They then measured the distance from those center points to the front and back of the notch.

The team placed metal beads at these three centers and took lateral radiographs using the quadrant method, according to Davis. They then seated a 7-mm femoral offset aimer at the vertical height of the ACL center, he said, and placed a pin through the aimer to mark a point on the lateral wall of the notch.

Results of the study illustrated that the femoral attachment of the ACL and its bundles can be identified through a method based on the height of these structures on the lateral wall of the notch, Davis said. Intra-operatively, a 7-mm femoral offset aimer seated at the height of the central ACL directs a pin about halfway between the ACL central and anteromedial bundle attachments. Then the shallow and deep ACL positions and their bundles can be referenced to a vertical line that starts at the low point of the notch’s lateral wall or cartilage borders, he explained.

“Whether you are using rigid reamers in a hyperflexed position or flexible reamers, once you have established your starting point you can then produce an anatomic femoral tunnel that is based upon a reproducible reference point that can be seen intra-operatively based upon the lowest point of articular cartilage,” Davis said.

Reference:

Davis AD, Brown C, Steiner ME. Simple guidelines for anatomic femoral tunnel placement in ACL reconstruction. Paper #17. Presented at the American Orthopaedic Society for Sports Medicine Annual Meeting  2012. July 12-15. Baltimore.

Biomarkers could be used to prevent atrophy in ACL-deficient patients, study finds | Orthopedics

Biomarkers could be used to prevent atrophy in ACL-deficient patients, study finds | Orthopedics

Biomarkers could be used to prevent atrophy in ACL-deficient patients, study finds

• July 18, 2012

BALTIMORE — ACL reconstruction is followed by a significant increase in pro-inflammatory biomarkers such as C-reactive protein and Interleukin-6, which in combination with elevated transforming growth factor-beta levels can contribute to and promote the development of muscle atrophy, according to a study presented at the American Orthopaedic Society for Sports Medicine Annual Meeting 2012, here.

“Patients [who sustain ACL tears] have significant muscle atrophy, and often when patients are discharged, 6 months or so after their tear, they still have strength deficits of around 40% or so,” Christopher L. Mendias, PhD, ATC, said during his presentation. With no known ways to prevent such atrophy, “we wanted to identify if there are any cytokines or signaling molecules that can actually induce muscle atrophy and if they are elevated in [these] patients — because then we could potentially target that and block some muscle atrophy, and that might be beneficial,” he said.

Biomarkers: patients vs. controls

Mendias and colleagues studied 18 patients who sustained complete non-contact ACL tears and underwent reconstructive surgery. They took blood samples preoperatively, at the time of surgery and at postoperative follow-up visits held several days, 2 weeks, 5 weeks, 12 weeks, 18 weeks and 26 weeks afterwards.  They also took blood samples from 27 control subjects with no history of knee injury.

For both groups, the investigators looked for circulating levels of the biomarkers cartilage oligomeric matrix protein (COMP), C-reactive protein (CRP), Interleukin-6 (IL-6) and transforming growth factor-beta (TGF-ß).

The results reportedly showed elevated CRP and IL-6 levels and decreased COMP levels at the first postoperative follow-up. The analysis done at the second follow-up, however, revealed that COMP, CRP and IL-6 levels returned to baseline, but TGF-ß levels were elevated.

At the third postoperative follow-up, all levels returned to their preoperative states.

Preventing atrophy

“CRP had the most profound response,” Mendias said. “Right after surgery, CRP levels went up almost 50-fold, and then they fell quite rapidly so that by the second postoperative visit they were back down to basal levels.”

These findings may help physicians prevent atrophy in patients following ACL reconstruction, he noted.

“We think the combination of these factors — elevation of myostatin, TGF-ß, IL-6 and possibly some others — are driving that initial muscle atrophy we see in our ACL-deficient patients,” Mendias concluded. “That opens the door potentially for us possibly blocking this. In particular, myostatin has a lot of potential advantages in blocking it and preventing some of this muscle atrophy.”

Reference:

Mendias CL, Lynch EB, Sibilsky ER, et al. Changes in circulating biomarkers of cartilage turnover and inflammation after anterior cruciate ligament reconstruction and rehabilitation. Paper #37. Presented at the American Orthopaedic Society for Sports Medicine Annual Meeting 2012. July12-15. Baltimore.

Bioinspired nanofibers support chondrogenesis for articular cartilage repair

Bioinspired nanofibers support chondrogenesis for articular cartilage repair

1. Jeannine M. Coburn^a,
2. Matthew Gibson^b,
3. Sean Monagle^b,
4. Zachary Patterson^b, and
5. Jennifer H. Elisseeff^a,^b,¹

+ Author Affiliations

1. Translational Tissue Engineering Center, Wilmer Eye Institute, and Departments of ^aChemical and Biomolecular Engineering and
2. ^bBiomedical Engineering, The Johns Hopkins University, Baltimore, MD 21287

1. Edited* by Robert Langer, Massachusetts Institute of Technology, Cambridge, MA, and approved May 4, 2012 (received for review January 4, 2012)

Abstract

Articular cartilage repair remains a significant and growing clinical challenge with the aging population. The native extracellular matrix (ECM) of articular cartilage is a 3D structure composed of proteinaceous fibers and a hydrogel ground substance that together provide the physical and biological cues to instruct cell behavior. Here we present fibrous scaffolds composed of poly(vinyl alcohol) and the biological cue chondroitin sulfate with fiber dimensions on the nanoscale for application to articular cartilage repair. The unique, low-density nature of the described nanofiber scaffolds allows for immediate cell infiltration for optimal tissue repair. The capacity for the scaffolds to facilitate cartilage-like tissue formation was evaluated in vitro. Compared with pellet cultures, the nanofiber scaffolds enhance chondrogenic differentiation of mesenchymal stems cells as indicated by increased ECM production and cartilage specific gene expression while also permitting cell proliferation. When implanted into rat osteochondral defects, acellular nanofiber scaffolds supported enhanced chondrogenesis marked by proteoglycan production minimally apparent in defects left empty. Furthermore, inclusion of chondroitin sulfate into the fibers enhanced cartilage-specific type II collagen synthesis in vitro and in vivo. By mimicking physical and biological cues of native ECM, the nanofiber scaffolds enhanced cartilaginous tissue formation, suggesting their potential utility for articular cartilage repair.

• biomaterials
• electrospin
• tissue engineering
• regenerative medicine

Pre-Injury Cartilage Biomarkers Associated With Subsequent Anterior Cruciate Ligament Injuries

Pre-Injury Cartilage Biomarkers Associated With Subsequent Anterior Cruciate Ligament Injuries

Article Date: 17 Jul 2012 - 1:00 PDT

U.S. Army researchers made a surprising discovery while examining the impact of an anterior cruciate ligament (ACL) tear (a common knee injury), on four serum biomarkers associated with cartilage health. The researchers found that pre-injury concentrations for all but one of the four serum biomarkers studied were associated with the subsequent likelihood of ACL injury. The findings were presented at the annual meeting of the American Orthopaedic Society for Sports Medicine (AOSSM).

"We expected to see post-injury differences in biomarkers, but were astonished that the biomarkers showed measurable differences months or years prior to injury," said U.S. Army Lt. Col. Steven Svoboda, M.D., during his presentation, titled The Association between Serum Biomarkers of Cartilage Turnover and Subsequent Anterior Cruciate Ligament Rupture. "If we can identify people predisposed to ACL tears, one day we may be able to prevent injuries before they occur."

Svoboda, an orthopedic surgeon at Keller Army Community Hospital in West Point, N.Y., is director of the John A. Feagin, Jr., Sports Medicine Fellowship and head team physician for the West Point football program. Svoboda presented the Army research findings at the AOSSM's O'Donoghue Sports Injury Research Award Presentation. This award is given annually to the best overall paper that deals with clinical based research or human in-vivo research.

Researchers measured pre-injury levels of four biomarkers of cartilage turnover and metabolism in 45 ACL-injured subjects and 45 control subjects who were matched to the injured subjects by height, sex, weight and age to see if there were differences. Pre-injury samples for all subjects were stored in the Department of Defense Serum Repository, which maintains serum samples drawn from service members at various points during their military careers.

They found that small differences (1 nanogram/milliliter) in pre-injury levels of three of the four biomarkers were associated with being more likely to sustain a subsequent ACL injury than the control group. In fact, an increase in one biomarker was associated with being 19 times more likely to sustain a later injury.

ACL tears are endemic, with 150,000 ACL injuries in the U.S. each year among military personnel, athletes and others with physically demanding careers or pursuits. Several recent studies have shown that high-risk biomechanical movement patterns, specifically excessive knee valgus angle during landing - or landing knock-kneed - causes increased pressure on the joint. "Our study adds to existing knowledge by raising the possibility of a link between risky movement patterns and biochemical processes associated with cartilage metabolism," added Dr. Svoboda. "Coaches and athletic trainers of the future may help athletes with high biomarker levels reduce their risk of ACL injury by improving their balance and motor control or correcting how they jump and land."

The study also has implications for the study of post-traumatic osteoarthritis (PTOA) because a high percentage of those who experience ACL tears go on to develop PTOA. An imbalance in the ability of cartilage to regenerate itself has been theorized as a critical component in the development of osteoarthritis.

The ACL injured cases for this study were 45 of 71 subjects from an existing clinical trial comparing outcomes for ACL reconstructions performed with two different autograft techniques. Patients were predominately male (86.7 percent) with a mean age of 20.26 years. The study was supported by a grant from the Orthopaedic Research & Education Foundation.

Rehabilitation Following Rotator Cuff Surgery Requires Change

Rehabilitation Following Rotator Cuff Surgery Requires Change


Article Date: 16 Jul 2012 - 0:00 PDT


A new Hospital for Special Surgery study suggests that the current rehabilitation used for patients undergoing tendon-bone repairs such as rotator cuff repair may be partially to blame for the high rates of failed healing after surgery. Experiments in a rat model of this injury suggest that immobilizing the limb for four to six weeks after surgery, rather than quickly starting physical therapy, improves healing.

"Before we did this study, we thought that delaying motion for a short period of time, seven to ten days, and then starting physical therapy would be the most beneficial to tendon healing. However, from the data in this study, it appears we should be immobilizing our patients for longer periods of time," said Scott Rodeo, M.D., principal investigator of the study and co-chief of the Sports Medicine and Shoulder Service at Hospital for Special Surgery (HSS) in New York City.

Carolyn Hettrich, M.D., MPH, who was an HSS resident when she conducted the study, will present the study July 14 at the annual meeting of the American Orthopaedic Society for Sports Medicine (AOSSM), held in Baltimore.

The rotator cuff is a set of a four small muscles in the shoulder that allow the upper arm to rotate. When a rotator cuff is torn, the tendon part of the muscle tears away from the bone of the upper arm. During a repair surgery, a surgeon reattaches the tendon to the bone and a surgery's success is dependent on how well the interface between the tendon and bone heals. Studies have shown that 20%-40% of patients undergoing rotator cuff surgery have failed healing. These patients have poorer outcomes, including decreased strength and decreased range of motion.

Rehabilitation after rotator cuff surgery usually consists of immobilizing the shoulder in a sling for seven to ten days, physical therapy with passive and assisted motion for six weeks, followed by physical therapy with active motion for six weeks. However, there is little data on the optimum rehabilitation program, and clinicians recognize there is a delicate balance between minimizing movement after surgery to protect the repair and allowing movement to prevent joint stiffness.

To explore the timing of post-operative rehabilitation, investigators at HSS conducted experiments using a rat model of patellar tendon injury and repair. The investigators used a small metal frame to hold the joint in place and then used a specially designed motorized device to precisely apply loads of strain. One group of rats received a low load 50 times per day (analogous to a leg extension with no weight), another group received a moderate load 50 times per day and a third group had their joint immobilized for the entire study period. The animals were studied at 4, 10, 21, and 28 days.

The researchers found that rats that had their joint immobilized had the best healing with significantly less fibrocartilage or scar tissue than rats in the other two groups. Scar tissue is weaker than original tissue, and oftentimes scar tissue forms at the interface between bone and tendon during tendon repair surgery. The rats that were immobilized also had better connective tissue organization, higher load to failure, better bone mineral density, and fewer dead cells in the area that was operated on. During the healing and inflammatory process, there is a regeneration and remodeling of tissues, which sometimes involves cell death that can lead to inflammation.

"Very surprisingly, all of the data supported immobilization. The biomechanics, the histology, everything," said Dr. Hettrich. "The rats that were immobilized and didn't have any load through that period of healing did the best. This study suggests that we might want to consider immobilizing human patients for a little bit longer to let some of the post operative inflammation calm down, because excess inflammation might be having a harmful effect."

The investigators suggest that the best path to recovery for patients undergoing rotator cuff surgery might be to keep individuals in slings for six weeks and then start with passive motion therapy. However, studies are needed in humans to test this hypothesis and make firm clinical recommendations.

Dr. Hettrich is now an assistant professor of orthopedics in sports medicine at the University of Iowa. Dr. Rodeo's laboratory will be presented with the Cabaud award for the study at the annual AOSSM meeting. The award is given to the best basic science/laboratory research paper at the meeting.

MRI is Unnecessary for Diagnosing Acute Achilles Tendon Ruptures

Clinical Diagnostic Criteria
David N. Garras MD, Steven M. Raikin MD,
Suneel B. Bhat MD, MPhil, Nicholas Taweel DPM, PT,
Homyar Karanjia DPM
Received: 24 August 2011 / Accepted: 2 April 2012 / Published online: 27 April 2012
The Association of Bone and Joint Surgeons1 2012
Abstract
Background Achilles tendon ruptures are common in
middle-aged athletes. Diagnosis is based on clinical examination
or imaging. Although MRI is commonly used to
document ruptures, there is no literature supporting its routine
use and we wondered whether it was necessary.
Questions/purposes We (1) determined the sensitivity of
physical examination in diagnosing acute Achilles ruptures,
(2) compared the sensitivity of physical examination with
that of MRI, and (3) assessed care delays and impact
attributable to MRI.
Methods We retrospectively compared 66 patients with
surgically confirmed acute Achilles ruptures and preoperative
MRI with a control group of 66 patients without preoperative
MRI. Clinical diagnostic criteriawere an abnormalThompson
test, decreased resting tension, and palpable defect. Time to
diagnosis and surgical procedures were compared with those
of the control group.
Results All patients had all three clinical findings preoperatively
and complete ruptures intraoperatively (sensitivity
of 100%). MR images were read as complete tears in 60,
partial in four, and inconclusive in two patients. It took a
mean of 5.1 days to obtain MRI after the injury, 8.8 days for
initial evaluation, and 12.4 days for surgical intervention. In
the control group, initial evaluation occurred at 2.5 days
and surgical intervention at 5.6 days after injury. Nineteen
patients in the MRI group had additional procedures whereas
none of the control group patients had additional procedures.
Conclusions Physical examination findings were more
sensitive than MRI. MRI is time consuming, expensive,
and can lead to treatment delays. Clinicians should rely on
the history and physical examination for accurate diagnosis
and reserve MRI for ambiguous presentations and subacute
or chronic injuries for preoperative planning.
Level of Evidence Level II, diagnostic study. See the
Guidelines for Authors for a complete description of levels
of evidence.

Non-surgical treatment of common shoulder injury may increase chances of return-to-playnces of return-to-play

Non-surgical treatment of common shoulder injury may increase chances of return-to-play in baseball players

BALTIMORE, MD – Surgically repairing a painful shoulder injury in baseball players known as a SLAP tear (superior labral) varies widely and often doesn't allow for return to play at the same level as before the injury. However, researchers presenting their findings at the American Orthopaedic Society for Sports Medicine's Annual Meeting in Baltimore, Maryland suggest that nonsurgical treatment may be more beneficial.
"Our research showed that nonsurgical treatment of SLAP tears was more often successful than surgery, and in position players more frequently than for pitchers," said David Lintner, MD, lead researcher from Methodist Center for Sports Medicine in Houston, Texas. "We need more research to determine why the nonsurgical treatment was more beneficial to one population than the other, but our findings did illustrate that nonsurgical treatment should be preferred."
Lintner and his team performed a retrospective review of a 119 professional baseball players within a single organization who had persistent shoulder pain that limited their ability to compete. Sixty-eight patients had MRI-documented SLAP lesions and had failed initial physical therapy. All patients were initially treated non-surgically according to an algorithm focused on correcting the scapular dyskinesia and posterior capsular tightness. Of the 68 subjects with confirmed SLAP lesions, 45 were pitchers. Return to competition appeared to occur at a higher rate for position players than pitchers (73% vs. 40%).
"Returning to the same level of competition as before the injury, is almost always difficult for an athlete, and surgery is often thought of as the best avenue. With additional research, orthopaedists are finding different routes to treat some of the most common throwing injuries," said Lintner.