ACL Grafts: Diameter Does Matter, Sort Of
Clinical failure of anterior cruciate ligament (ACL) reconstructions continues to be a too-common scenario. The increasing incidence of ACL revision is due to a variety of factors, including greater intensity of postsurgical physical activity, technical issues, and anatomical influences of the proximal tibia and distal femur. Registries are important sources of data for ACL-related investigations, but I think they are most useful in clarifying experimental designs for more sophisticated clinical research.
In a cohort study in the October 16, 2019 issue of The Journal, Snaebjornsson et al. examined the influence of ACL graft diameter on the risk of revision surgery over 2 years in >18,000 subjects whose data resided in the national knee ligament registries of Sweden and Norway. The vast majority of those patients (92.8%) received a hamstring autograft, with 7.2% receiving a patellar tendon autograft. Overall, the 2-year rate of ACL revision was 2.63% for patellar tendon autografts and 2.08% for hamstring autografts, a statistically nonsignificant difference in relative risk.
However, the authors found an important correlation between graft diameter in the hamstring tendon cohort, with autografts <8 mm in diameter being associated with a higher risk of revision, compared with larger-diameter hamstring autografts. Additionally, patients treated with hamstring graft diameters of ≥9 mm or ≥10 mm had a lower risk of ACL revision surgery than those treated with patellar tendon grafts of any size.
One key limitation that should influence our interpretation of this study is a lack of detail regarding how compliant surgeons were intraoperatively with the use of the measurement device that is depicted in the manuscript and shown above. In addition, the limitations of registry data did not permit the authors to adjust for postsurgical exposures, such as return to sport, the increasing intensity of which makes rerupture more likely. Additional relevant information that would have aided interpretation of the findings includes the relative size of the tibia and femur, lateral condyle size and shape, and proximal tibial slope.
Despite these limitations, this study should prompt further research that uses robust clinical designs to more fully investigate the impact of graft diameter on ACL rerupture rates.
Marc Swiontkowski, MD
JBJS Editor-in-Chief
December 2018 Article Exchange with JOSPT
In 2015, JBJS launched an “article exchange” collaboration with the Journal of Orthopaedic & Sports Physical Therapy (JOSPT) to support multidisciplinary integration, continuity of care, and excellent patient outcomes in orthopaedics and sports medicine.
During the month of December 2018, JBJS and OrthoBuzz readers will have open access to the JOSPT article titled “Perceptions of Rehabilitation and Return to Sport Among High School Athletes With Anterior Cruciate Ligament Reconstruction: A Qualitative Research Study.”
In this cross-sectional study, researchers looked at 10 high-school-aged individuals who had undergone ACL reconstruction surgery and had not returned to sport. They found that psychosocial barriers to return to sport (e.g., persistent uncertainty about full recovery) were reported with greater consistency than physical barriers. The authors suggest that peer mentoring groups to facilitate psychosocial support during rehabilitation might help.
What’s New in Sports Medicine 2018
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. Click here for a collection of all OrthoBuzz Specialty Update summaries.
This month, OrthoBuzz asked Albert Gee, MD, a co-author of the April 18, 2018 Specialty Update on Sports Medicine, to select the five most clinically compelling findings from among the 30 studies cited in the article.
Anterior Cruciate Ligament (ACL) Reconstruction
–The conversations about graft selection for ACL reconstruction go on. A meta-analysis of 19 Level-I studies comparing 4-strand hamstring autograft with patellar tendon grafts1 revealed no differences in terms of rupture rate, clinical outcome scores, or arthrometer side-to-side testing at >58 months of follow-up. The prevalence of anterior knee pain and kneeling pain was significantly less in the hamstring group, and that group also exhibited a lower rate of extension deficit.
Cartilage Repair
–Fourteen-year outcomes from a randomized controlled trial (n = 80 patients) comparing autologous chondrocyte implantation (ACI) with microfracture for treating large focal cartilage defects included the following:
- No significant between-group difference in functional outcome scores
- Fairly high treatment failure rates in both groups (42.5% in the ACI group; 32.5% in the microfracture group)
- Radiographic evidence of grade 2 or higher osteoarthritis in about half of all patients
These findings raise doubts about the long-term efficacy of these two treatments.
Rehab after Rotator Cuff Repair
–A randomized trial comparing early and delayed initiation of range of motion after arthroscopic single-tendon rotator cuff repair in 73 patients2 found no major differences in clinical outcome, pain, range of motion, use of narcotics, or radiographic evidence of retear. The early motion group showed a small but significant decrease in disability. The findings indicate that early motion after this surgical procedure may do no harm.
Platelet-Rich Plasma (PRP)
–A systematic review of 105 human clinical trials that examined the use of PRP in musculoskeletal conditions revealed the following:
- Only 10% of the studies clearly explained the PRP-preparation protocol.
- Only 16% of the studies provided quantitative information about the compositi0on of the final PRP product.
- Twenty-four different PRP processing systems were used across the studies.
- Platelet composition in the PRP preparations ranged from 38 to 1,540 X 103/µL.
Consequently, care should be taken when drawing conclusions from such studies.
Meniscal Tear Treatment
–A follow-up to the MeTeOR trial (350 patients initially randomized to receive either a partial arthroscopic meniscectomy or physical therapy [PT]) found that crossover from the PT group to the partial meniscectomy group was significantly associated with higher baseline pain scores or more acute symptoms within 5 months of enrollment. Investigators also found identical 6-month WOMAC and KOOS scores between those who crossed over and those who had surgery initially. These findings suggest that an initial course of PT prior to meniscectomy does not compromise outcomes.
References
- Chee MY, Chen Y, Pearce CJ, Murphy DP, Krishna L, Hui JH, Wang WE, Tai BC,Salunke AA, Chen X, Chua ZK, Satkunanantham K. Outcome of patellar tendon versus 4-strand hamstring tendon autografts for anterior cruciate ligament reconstruction: a systematic review and meta-analysis of prospective randomized trials. Arthroscopy. 2017 Feb;33(2):450-63. Epub 2016 Dec 28.
- Mazzocca AD, Arciero RA, Shea KP, Apostolakos JM, Solovyova O, Gomlinski G, Wojcik KE, Tafuto V, Stock H, Cote MP. The effect of early range of motion on quality of life, clinical outcome, and repair integrity after arthroscopic rotator cuff repair. Athroscopy. 2017 Jun;33(6):1138-48. Epub 2017 Jan 19.
ACL Trial Quality Has Improved Over Time
The randomized controlled trial (RCT) may be the gold standard of clinical research, but not all RCTs are created equal. In the December 20, 2017 issue of The Journal, Kay et al. set out to determine the historical quality of more than 400 RCTs relating to anterior cruciate ligament (ACL) reconstruction published between 1985 and 2016.
The authors evaluated the studies using the Detsky quality index (on which a score of ≥75% is considered “high” methodological quality) and the CONSORT checklist. Fifty-two percent of the studies analyzed were surgical trials (graft choice, femoral fixation method, and single- vs double-bundle techniques), while 48% were nonsurgical trials (analgesic and rehabilitation regimens).
The mean Detsky score across all studies was 68.9% ± 13.2%. Forty-two percent of the studies were considered high-quality according to Detsky scores. There was no significant difference in mean Detsky scores between surgical and nonsurgical trials.
The authors noted a substantial increase in the number of ACL RCTs over time, although that number has not changed significantly since 2009, which is coincidentally the year that JBJS and many other journals required authors to use the CONSORT flow diagram. Notably, the reporting of methodologically sound randomization processes and the prospective calculation of sample sizes have also improved significantly in recent years.
Both the inclusion of a CONSORT flow diagram and the year published were significant predictors of the quality score. A mere 5% of trials published in 2008 or prior included the CONSORT flow diagram, while >40% of trials published since 2009 had a flow diagram.
While the authors are encouraged that “close to 50% of trials in this study reported blinding of outcome assessors,” they say areas for improvement include better “descriptions of allocation concealment and intent-to-treat analyses.”
Sports Medicine Update
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. Click here for a collection of all OrthoBuzz Specialty Update summaries.
The May 17, 2017 JBJS Specialty Update on Sports Medicine reflects evidence in the field of sports medicine published from September 2015 to August 2016. Although this review is not exhaustive of all research that might be pertinent to sports medicine, it highlights many key articles that contribute to the existing evidence base in the field.
Topics covered include:
- Prevention of Musculoskeletal Injuries
- Autograft vs Allograft ACL Reconstruction
- Anterior Shoulder Stabilization
- Hip Arthroscopy
High Rates of Return to Play and Patient Satisfaction after ACL Reconstruction
The estimated annual cost of surgical treatment for anterior cruciate ligament (ACL) ruptures in the US is $2 billion. Are ACL surgery patients—and the health care system—getting significant value for all that money spent?
In the May 3, 2017 issue of The Journal of Bone & Joint Surgery, Nwachukwu et al. set out to answer that question by retrospectively analyzing rates of return to play and satisfaction among 231 ACL-surgery patients (mean age of 27 years) who were followed for a mean of 3.7 years. The authors found that:
- 87% had returned to play at a mean of 10 months after surgery.
- 89% of the 171 athletes eligible to return to their prior level of competition did so.
- 85% said they were “very satisfied” with the outcome, and 98% stated they would have the surgery again.
Not surprisingly, patients were more likely to say they were “very satisfied” if they had returned to play.
The authors also found that the use of patellar tendon autograft increased the chance of returning to play, while preoperative participation in soccer or lacrosse decreased the likelihood of returning to play. Those who participated in basketball, football, skiing, and tennis had higher return-to-play rates than those who participated in the two aforementioned sports.
In addition, Nwachukwu et al. found that one-third of those who did not return to sports reported fear of reinjury as the reason. The authors encourage surgeons to understand that “psychological readiness, fear of reinjury, and mental resiliency influence the probability of an athlete returning to play.”
In her commentary, Elizabeth Matzkin, MD cautions readers to interpret the Level IV study’s findings cautiously. She calls for “better prospective, homogeneous studies” to more accurately assess which surgical graft types and specific sports are more or less likely to result in patients returning to play. Nevertheless, the study, she says, “forces us to look at the big picture: What can we do to make ACL [reconstruction] better for our patients?”
Blood-Vessel Anomaly Boosts DVT Risk after ACL Reconstruction
The overall rate of symptomatic lower-extremity deep vein thrombosis (DVT) following arthroscopic ACL procedures is reported to be <0.3%, and guidelines from the American College of Chest Physicians recommend against DVT prophylaxis prior to arthroscopic knee surgery, unless a patient has risk factors for blood clots. But some patients are unknowingly at high risk for clots, as a case report by Ackerman et al. in the June 10, 2105 JBJS Case Connector shows.
A 45-year-old woman presented for arthroscopic ACL reconstruction in her left knee. Unbeknownst to her or her surgeons, the patient had asymptomatic May-Thurner syndrome—an anatomic variant of the iliac blood vessels in which the right common iliac artery crosses over the left common iliac vein, compressing the vein against the lumbar spine.
Nine days after ACL surgery, the patient showed up in the ED with pain and swelling in the operative leg. Ultrasound revealed an extensive DVT extending distally from the common femoral vein. Imaging of the chest and cardiac workups were negative for heart or lung thromboembolism.
A heparin drip was started, and a vascular surgeon ordered a left-leg venograph, which revealed a large clot extending from the origin of the left common iliac vein to the insertion site of the catheter in the popliteal vein. Severe stenosis of the left common iliac vein confirmed May-Thurner syndrome (see image below).
Treatment consisted of an infusion of tissue plasminogen activator (Alteplase) directly to the clot, continued intravenous heparin, and an angioplasty with stents to open the stenosed left common iliac vein. Mechanical thrombolysis and aspiration of a residual femoral vein thrombus was accomplished with a Trellis device.
Postoperatively the patient was transitioned to therapeutic warfarin for six months and instructed to wear compression stockings. She completed her ACL physical therapy protocol uneventfully, and one year after the ACL reconstruction, the knee graft was stable and there was no evidence of post-thrombotic syndrome.
The authors remind orthopaedists that May-Thurner syndrome, which is more common in women than men, should be suspected in the presence of an extensive iliofemoral DVT. They emphasize that multimodal and aggressive treatment, in consultation with a vascular specialist, should be initiated to bust the clot and reduce the risk of post-thrombotic syndrome. Post-clot, such patients should be maintained on warfarin for a minimum of six months, and patients with stents often require lifelong aspirin therapy.
What’s New in Sports Medicine: 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 April 15, 2015 Specialty Update on sports medicine:
Shoulder
–A systematic review of Level-I and II studies suggests that the structural integrity of rotator cuff repairs (or lack thereof) does not correlate with validated patient subjective outcome measures.
–Authors of a randomized clinical trial comparing open and arthroscopic stabilization for recurrent anterior shoulder instability concluded that young male patients with visible Hill-Sachs lesions on radiographs may fare better with open repairs.
–A quantitative literature synthesis of 31 studies (2,813 shoulders) supported primary surgery for highly active young adults who sustain an anterior shoulder dislocation.
–Following rotator cuff surgery, patients randomized to receive a combined axillary and suprascapular nerve block experienced less pain and a lower frequency of rebound pain in the first 36 hours than those receiving only a suprascapular nerve block.
–A Level-II meta-analysis of early passive motion versus strict sling immobilization after arthroscopic rotator cuff repair found that early passive motion resulted in improved forward flexion at 6 and 12 months, with no apparent increased retear rate.
Knee
–A randomized trial comparing single- and double-bundle ACL reconstruction with the use of hamstring autograft found no differences in pivot shift or clinical scores at two years.
–Twenty patients with subacute ACL injuries were randomized to “prehabilitation” or control groups. At 12 weeks after surgery, the prehab group showed sustained improvements in single-leg hop and Cincinnati scores, but peak torque and muscle-mass gains had regressed to levels similar to those in the control group.
–A randomized study comparing contralateral versus ipsilateral hamstring tendon harvest for ACL repair identified neither drawbacks nor advantages with the contralateral approach.
–Sixty patients who’d received an isolated meniscal repair were randomized to get either a traditional rehab protocol (brace and toe-touch weigh bearing) or “free rehabilitation.” Based on MRI, partial healing or lack of healing occurred in 28% of the free rehabilitation group and in 36% of the traditional group.
–Authors of a systematic review concluded that nonirradiated allogenic tissue may be superior to radiated allografts for primary ACL reconstruction.
Cartilage Regeneration
–A randomized controlled trail comparing microfracture alone to microfracture plus application of a novel chitosan-based device demonstrated greater lesion filling and superior repair tissue with the novel device, although there were no differences in clinical benefit and safety at 12 months.
–A randomized controlled trial comparing accelerated with conventional rehabilitation following cartilage repair found that the accelerated group reached full weight-bearing two weeks earlier than the conventional group and reported higher quality-of-life scores.
Hip
–In a Level-II study of a population with acute hamstring injuries, those who received a single autologous platelet-rich plasma injection plus rehab had significantly reduced return-to-play time than a group that received rehab without the injection.
Elbow
–A randomized study of 230 patients with chronic lateral epicondylitis found that those receiving leukocyte-enriched platelet-rich plasma had “clinically meaningful improvement” in pain at 24 weeks, compared to those in an “active control” group.
Foot & Ankle
–A randomized study of 84 patients with nonsurgically treated Achilles tendon tears showed no significant differences in rerupture rates or return-to-work times between a group given a weight-bearing cast and a group given a non-weight-bearing cast.
–A randomized trial of 200 patients with Achilles ruptures compared stable surgical repair and accelerated rehabilitation to nonoperative management. Surgical repair was not found to be superior to nonoperative treatment in terms of functional results, physical activity, or quality of life.
JBJS Editor’s Choice—Diabetes Boosts Infection Risk After ACL Surgery
In the March 18 2015 edition of The Journal, Brophy et al. and investigators from the MOON Knee Group focus on that very rare complication of ACL reconstruction surgery: infection. They prospectively followed a large cohort of more than 2,100 patients treated at multiple sites from 2000 to 2005.
The overall infection rate was less than 1%, which is in line with rates found in other studies. What was most notable is that the infection rate among patients with diabetes was 8.7% but only 0.7% in patients without diabetes. Statistically, having diabetes increased the odds of a post-ACL infection by nearly 19 times. Patients with diabetes should be counseled preoperatively so that they can be extra vigilant about detecting early signs of infection. Screening for diabetes prior to ACL surgery is not currently a standard of care, but it might be considered a reasonable approach in light of these findings. Surprisingly age and BMI were not associated with increased infection risk, and there was only a trend toward smokers being at higher risk.
Brophy et al. also found that patients receiving hamstring autografts were more than four times as likely to experience infection as those who received bone-tendon-bone (BTB) autografts. The authors’ hypothesis that the deep dissection required for hamstring harvest might increase infection risk seems plausible. It may also be that younger, healthier, more active patients (with presumably stronger immune systems) were more often offered BTB grafts.
What I like most about this study is that the MOON registry has very accurate clinical data because the investigators are clinicians who are highly invested in data quality. This is in distinction to studies that rely on administrative databases, where the coding of events is done by non-clinicians who may have less interest in entering highly accurate data. Still, as clinically accurate as MOON data are, they are from more than a decade ago. Although the risk of post-ACL infection may be even lower in this decade, with these already-low rates, it would be difficult to statistically prove that progress.
Marc Swiontkowski, MD
JBJS Editor-in-Chief
What’s New in Orthopaedic Rehabilitation
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 key findings from studies cited in the November 19, 2014 Specialty Update on orthopaedic rehabilitation:
General Orthopaedics
- Among geriatric hip fracture patients, those who received comprehensive postsurgical care (including a multidisciplinary assessment of health, function, and social situation) had significantly more upright time and better Short Physical Performance Battery scores than counterparts who received hospital physiotherapy and conventional care.
- Seventy-two percent of 51 orthopaedic inpatients exceeded their target goal for prescribed partial weight bearing after being trained. The inability to comply with the training was not associated with poorer outcomes at three months, suggesting clinical support for less-restrictive weight-bearing protocols.
- A prospective study of 38 unilateral TKA patients revealed that results from squatting exercises more accurately predicted overall functional difficulties than did results from standing with increased weight.
- A prospective randomized trial among 36 patients who underwent primary ACL reconstruction with semitendinosus-gracilis autograft found no difference in knee laxity, peak isometric force, or subjective IKDC scores between those who had aggressive early rehabilitation versus those undergoing a nonaggressive protocol.
Pediatric Rehabilitation (focused on cerebral palsy patients)
- Among 100 young children with cerebral palsy, the development of mobility and self-care was faster in children with less severe levels as assessed with the Gross Motor Function Classification System (GMFCS). A separate assessment study supported the validity of the Patient Reported Outcomes Measurement Information System (PROMIS) Mobility Short Form.
- Results from two gait-analysis studies suggested that using gait analysis in planning interventions for children with cerebral palsy can lead to beneficial alterations in gait.
Amputation and Prosthetics
- A study comparing functional outcomes after two types of unilateral transtibial amputation (modified Ertl and modified Burgess procedures) found no significant between-group differences.
Spinal Cord Injury
- A study to assess the safety and efficacy of ReWalk (a lower-limb powered exoskeleton) among 12 patients with motor-complete thoracic spinal cord injury found that all subjects were able to walk independently and continuously for at least 50 to 100 meters. No falls were reported, but a few adverse events related to pressure and irritation occurred.
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