Tag Archive | allograft

Structural Allografts Can Work for Acetabular Defects in THA

Structural Allograft for OBuzzAllograft bone is used often in orthopaedic surgery. However, the use of structural allografts to address large acetabular defects in total hip arthroplasty (THA) is not common. But it may become more so in light of the study by Butscheidt et al. in the August 15, 2018 issue of JBJS. The authors add to our knowledge about these relatively rare procedures by evaluating the incorporation of structural acetabular allografts into host bone among 13 complete pelvic explants containing allograft that had been in place for a mean of 13 years.

Using sophisticated imaging and histological techniques, the authors found that in 10 out of the 13 specimens retrieved, 100% of the interface was characterized by direct contact and additional overlap of the allograft bone and the host bone. The remaining 3 allografts showed direct contact along 25% to 80% of the interface.  The authors found no correlation between ingrowth of the host bone into the allograft and the amount of time the allograft had spent in situ, leading them to surmise that “a large proportion of the incorporation process may be completed within the first weeks.”

Large, structural allografts are not commonly used for acetabular reconstructions, as most surgeons seem to favor other options.  (See the JBJS Clinical Summary on “Managing Acetabular Defects in Hip Arthroplasty.”) While a postmortem study of 13 cases may not be “practice-changing,“ the Butscheidt et al. analysis does provide some detailed clarity as to what surgeons can expect from these large allograft reconstructions in terms of incorporation with host bone. Obviously, one limitation of this study is that structural allografts that never incorporated with the host bone probably failed early and would not be available for analysis in a long-follow-up retrieval study.

Chad A. Krueger, MD
JBJS Deputy Editor for Social Media

JBJS 100: Gait Initiation, ACL Replacement

JBJS 100Under one name or another, The Journal of Bone & Joint Surgery has published quality orthopaedic content spanning three centuries. In 1919, our publication was called the Journal of Orthopaedic Surgery, and the first volume of that journal was Volume 1 of what we know today as JBJS.

Thus, the 24 issues we turn out in 2018 will constitute our 100th volume. To help celebrate this milestone, throughout the year we will be spotlighting 100 of the most influential JBJS articles on OrthoBuzz, making the original content openly accessible for a limited time.

Unlike the scientific rigor of Journal content, the selection of this list was not entirely scientific. About half we picked from “JBJS Classics,” which were chosen previously by current and past JBJS Editors-in-Chief and Deputy Editors. We also selected JBJS articles that have been cited more than 1,000 times in other publications, according to Google Scholar search results. Finally, we considered “activity” on the Web of Science and The Journal’s websites.

We hope you enjoy and benefit from reading these groundbreaking articles from JBJS, as we mark our 100th volume. Here are two more:

The Initiation of Gait
R A Mann, J L Hagy, V White, D Liddell: JBJS, 1979 March; 61 (2): 232
Using electromyography and force-plate data, this study of 10 healthy men and women revealed that the deceptively simple motion of taking the first step from a standing position is initiated by the unbalanced body harnessing complex neural mechanisms, muscular activity, and biomechanical forces. The findings can inform today’s efforts to prevent falls among the elderly.

Replacement of the Anterior Cruciate Ligament using a Patellar Tendon Allograft
S P Arnoczky, R F Warren, M A Ashlock: JBJS, 1986 January; 68 (3): 376
Fresh or deep-frozen? That was the question researchers asked in this study of 25 dogs whose patellar tendons were replaced with one of these two types of allografts. The fresh allografts incited a marked inflammatory and rejection response, while the deep-frozen allografts appeared to be benign and behaved comparably to autogenous patellar tendon grafts. In the 30-plus years since this 1986 study, we have learned a lot about the immunogenicity and biologic character of transplanted allografts, and this important research continues.

ACL Surgery Trends, 2007 to 2014

In a population-based epidemiological study published in the July 6, 2016 Journal of Bone & Joint Surgery, Tibor et al. found that from 2007 to 2014:

    • Many ACL-reconstruction surgeons changed from a transtibial approach to either an anteromedial portal or lateral approach for femoral-tunnel drilling.
    • Most did not substantially change the types of grafts they used.
    • Many eschewed first-generation bioabsorbable implants in favor of biocomposite fixation devices.

Femoral Tunnel_7_6_16.gif

The authors found no change in cumulative revision rates during the study period.

Tibor et al. analyzed information from 21,686 primary ACL reconstructions housed in a Kaiser Permanente registry that collected data from surgeries performed in 33 hospitals by 246 surgeons in urban, rural, and suburban settings in three Western US states. This wide-ranging data set, the authors say, “increases the generalizability of our findings to other community-based surgeons.”

The authors admit, however, that the epidemiological nature of the study “offers only limited insight into associated outcomes,” and they were unable to analyze cost trends because the registry does not capture cost data.

What’s New in Spine Surgery: Level I and II Studies

Every month, JBJS publishes a Specialty Update—a review of the most pertinent and impactful studies published in the orthopaedic literature during the previous year in 13 subspecialties. Here is a summary of selected findings from Level I and II studies cited in the June 17, 2015 Specialty Update on spine surgery:

  • A database study to determine the prevalence of venous thromboembolic events after spinal fusion found that risk factors for such events included hypercoagulability, certain medical comorbidities, older age, and male sex.
  • An RCT comparing allograft alone versus allograft plus bone marrow concentrate to accomplish spine fusion in adults with spondylolisthesis found very poor union rates in both groups, although allograft with bone marrow concentrate delivered slightly better results.
  • A meta-analysis of five studies (253 patients) found no pain or functional differences when unilateral percutaneous kyphoplasty was compared with bilateral (same-vertebra) kyphoplasty for osteoporotic compression fractures. The unilateral approach was associated with shorter operative times, however.
  • An RCT comparing the analgesic efficacy and clinical utility of gabapentin, pregabalin, and placebo in patients undergoing spinal surgery found that pregabalin outperformed the other two interventions immediately after surgery postoperative and up to three months postoperatively.
  • In an RCT comparing open-door to French-door laminoplasty for cervical compressive myelopathy, both techniques were found to be equivalent in terms of neurological recovery and perioperative complications, but patients receiving the open-door technique had more kyphosis and less cervical range of motion postoperatively.
  • An update to a 2002 Cochrane review found no significant outcome differences between supervised and home-exercise rehabilitation programs after lumbar disc surgery.
  • A systematic review/meta-analysis showed that radiofrequency denervation of facet joints is more effective than placebo in achieving functional improvement and pain control in patients with chronic low back pain.
  • A Level II diagnostic study concluded that with a magnification of 150% and a good pair of flexion and extension radiographs following anterior cervical arthrodesis, pseudarthrosis was noted with >1 mm of motion between fused interspinous processes with 96.1% specificity and a positive predictive value of 96.9%.
  • A Level I therapeutic study comparing the efficacy of intravenous tranexamic acid, epsilon-aminocaproic acid, and placebo to reduce bleeding in 125 adolescent patients undergoing posterior fusion for idiopathic scoliosis found less intraoperative and postoperative blood loss and higher hematocrit levels with the antifibrinolytics than with placebo. However, transfusion requirements were no different between the groups.
  • A randomized comparison of navigated versus freehand techniques for pedicle screw insertion during lumbar procedures found that surgeon radiation exposure with freehand technique is up to 10 times greater than with use of navigation.

Restoring Cartilage: The Holy Grail of Orthopaedics

For decades, researchers have been investigating different methods of cartilage repair, but no approach has yet risen to “gold standard” status. In the June 24, 2015 edition of JBJS Case Connector, “Case Connections” looks at three different restorative/replacement approaches to cartilage defects.

In the springboard case by Ramirez et al., a high school athlete’s full-thickness glenoid osteochondral defect was filled arthroscopically with particulated juvenile cartilage allograft (see image below).

F1.largeIn an earlier case report by Convery et al., the authors recommended placing additional autogenous bone beneath allografts to augment the host bed and enhance incorporation of the allograft’s osseous shell.

Welsch et al. alert surgeons to the possibility of hypertrophic cartilage opposite a defect that’s treated with a matrix-associated autologous chondrocyte transplant (MACT). And finally, Adachi et al. report on osteonecrosis of the femoral condyles that was treated with tissue-engineered cartilage combined with a hydroxyapatite scaffold enhanced with mesenchymal stem cells.

Although prospective studies with suitable control groups will be needed to prove the efficacy of these and other restorative techniques, early intervention with biologic restoration of the articular surface could eventually have a profound influence on patients with cartilage damage.

ACL Self-Repair Moving Toward Reality

Attempts by orthopaedists to repair torn human ACLs have failed for the most part, so surgeons now rely almost exclusively on removing the torn ligament and replacing it with autograft or allograft tissue. But now research at Harvard by Martha Murray, MD—a co-author of several JBJS studies—suggests that a torn ACL can be prompted to repair itself.

As Dr. Murray explains in a video, “bridge-enhanced” ACL repair uses stitches and a spongy scaffold injected with the patient’s blood placed between the torn ends of the ACL. The bridge helps healing clots to form and helps surrounding cells grow to rejoin the ends of the ligament. Preclinical studies using this technique have resulted in successful ACL repairs and rates of subsequent knee arthritis that were lower than those seen with reconstruction techniques. Bridge-enhanced ACL repair would also eliminate the need for tissue harvesting in the many patients who choose the autograft reconstruction option.

After reviewing the data from the preclinical studies, the FDA approved the first safety study of this technique in humans, which is now underway.