JBJS Classics: The Harris Hip Score
Each m
onth during the coming year, OrthoBuzz will bring you a current commentary on a “classic” article from The Journal of Bone & Joint Surgery. These articles have been selected by the Editor-in-Chief and Deputy Editors of The Journal because of their long-standing significance to the orthopaedic community and the many citations they receive in the literature. Our OrthoBuzz commentators will highlight the impact that these JBJS articles have had on the practice of orthopaedics. Please feel free to join the conversation about these classics by clicking on the “Leave a Comment” button in the box to the left.
The most lasting legacy from William Harris’s classic evaluation of post-traumatic mold arthroplasty published in 1969 is embodied in the paper’s subtitle, which refers to “a new method of result evaluation.” This end-result analysis evaluated 39 mold arthroplasties performed to treat traumatic arthritis at Massachusetts General Hospital between 1945 and 1965. Based on this series, the author at the time concluded that mold arthroplasty was the treatment of choice for most patients who require surgery for traumatic arthritis.
However, the most enduring part of this article can be found in the methods section, where the author proposed a hip score, a “single, reliable figure” designed to be equally applicable to different hip problems and different treatments. Dr. Harris designed the 100-point system to be reproducible and reasonably objective, giving a maximum of 44 points to a pain category, 47 points to functional capacity, 5 to range of motion, and 4 to absence of deformity. By using the scores pre- and postoperatively for this series of mold-arthroplasty patients, the author demonstrated how the new rating appeared to give a more accurate assessment of patients, relative to the Shepherd and Larson methods that were widely used at the time.
Dr. Harris broke down the function part of the score into daily activities (including stairs, socks and shoes, and comfort while sitting) and gait (with or without limping, with or without support). Over the years, this scale, along with the Postel Merle d’Aubigné developed in the 1950s, became the international gold standards to evaluate the pre- or postoperative state of the hip joint during everyday life. Not surprisingly, 46 years after its original publication, Dr. Harris’s paper remains the highest cited paper in the hip and knee arthroplasty literature, with nearly 2,500 citations.
Although the findings in this study focused mainly on post-traumatic arthritis treated by mold arthroplasty, the evaluation system proposed in the paper is used today in routine evaluations at almost every orthopedic center involved in hip arthroplasty. It’s used to clinically evaluate the hip joint before surgery and to evaluate the result after surgery at regular short-term follow-ups. It has also been used over the course of decades to evaluate the long-term performance of replaced joints. In addition, it is the clinical tool we use to compare various surgical techniques, different hip prosthesis designs, and case series from different institutions.
More recently, investigators have highlighted the importance of patient-reported measures of outcomes to better appreciate patient expectations before hip arthroplasty and to better evaluate patient satisfaction after surgery. Regardless of whether the primary goal of the operation is to relieve pain or get a person back on the athletic field, I think the system established by William Harris will remain the baseline for all arthroplasty surgeons, even if future scoring systems routinely incorporate patient-reported outcomes or quality-of-life measures.
Jean-Noel A. Argenson, MD, PhD
JBJS Deputy Editor for Adult Hip and Knee Reconstruction
JBJS Classics: The Role of Continuous Passive Motion in Orthopaedics
Each month during the coming year, OrthoBuzz will bring you a current commentary on a “classic” article from The Journal of Bone & Joint Surgery. These articles have been selected by the Editor-in-Chief and Deputy Editors of The Journal because of their long-standing significance to the orthopaedic community and the many citations they receive in the literature. Our OrthoBuzz commentators will highlight the impact that these JBJS articles have had on the practice of orthopaedics. Please feel free to join the conversation about these classics by clicking on the “Leave a Comment” button in the box to the left.
Based in part on clinical observations of persistent stiffness, pain, and cartilage damage after prolonged immobilization, in a 1960 JBJS paper, Robert B. Salter described degenerative changes in cartilage of rabbit knee joints that had been immobilized. He suggested that this “obliterative degeneration” might be related to adherence of synovium to the articular surface, and he wondered elsewhere in the orthopaedic literature, “If intermittent motion is good for articular cartilage, would continuous motion be even better?”
This background led to the classic December 1980 JBJS publication in which Salter and his colleagues hypothesized that “continuous passive motion of a synovial joint in vivo would have a beneficial biological effect on the healing of full-thickness defects in articular cartilage.”
To test the hypothesis, Salter et al. made full-thickness cartilage defects at four sites in the knees of 147 rabbits. The rabbits were subjected postoperatively to either immobilization, intermittent active motion (normal cage activity), or continuous passive motion (CPM) created by a custom-made apparatus. Outcome measures included clinical observation of the animals, joint stiffness, and histology.
The extent of ultimate postoperative stiffness, adhesions, and cartilage healing all varied with the degree of immobilization, leading the authors to conclude that CPM
- Was well tolerated by the animals without causing harm detectable by gross or histologic evaluation
- Was associated with fewer adhesions than immobilization, and
- Stimulated more rapid and complete cartilage restoration than either immobilization or intermittent active motion.
Subsequent work by Salter and co-workers evaluated the effect of CPM on other animal models of full-thickness cartilage defects, intra-articular fractures, acute septic arthritis, patellar tendon injury, ligament repair, autogenous and allogenic periosteal and osteoperiosteal grafts, and other conditions. Based in part on the favorable results of these pre-clinical studies as well as preliminary clinical trials, Salter suggested in CORR in1989 that CPM might be indicated after a host of other orthopaedic procedures, including open reduction and internal fixation of intra-articular or selected diaphyseal and metaphyseal fractures, capsulotomy and arthrolysis for post-traumatic arthritis, synovectomy for rheumatoid arthritis or hemophilic arthropathy, arthrotomy and drainage of septic arthritis, release of contractures or adhesions, metaphyseal osteotomy with internal fixation, and reconstruction of a medial collateral ligament.
A Google Scholar search in October 2014 indicated that the 1980 Salter at al. JBJS publication has been cited approximately 1,096 times. Many of the articles that cite the 1980 JBJS study appropriately focus on the effect of CPM on either the histology of cartilage repair, or the effect of CPM on adhesions and joint stiffness.
However, Salter’s observation of decreased stiffness in animals treated with CPM has been extrapolated to clinical applications that were not included in his original work, most notably total knee arthroplasty (TKA).Today the clinical use of CPM after arthroplasty is controversial. A 2010 Cochrane review, for example, identified 20 randomized controlled trials of 1,335 patients in which CPM had been evaluated after TKA. The review concluded that there is evidence that CPM increases knee flexion range of motion, but “the effects are too small to be clinically worthwhile.” A more recent 2014 Cochrane review of 11 randomized clinical trials involving 808 patients concluded that there is not enough evidence to conclude that CPM reduces venous thromboembolism after total knee arthroplasty.
With respect to CPM after cartilage-repair procedures, many other investigators have confirmed the findings Salter reported in 1980 in animal models. Indeed, the basic-science support is strong enough that CPM has been commonly used in humans after cartilage repair, yet its actual efficacy in people remains controversial. For example, in a 2010 systematic review, Fazalare and co-workers reviewed 1,087 human clinical studies in which CPM had been used after cartilage repair procedures. In spite of that large number of studies, Fazalare was unable to find any randomized, controlled studies related to CPM, and heterogeneity among procedures and outcome measures in those articles precluded performing a meta-analysis.
Authors of today may be envious of the more than 6,900 words and 52 photographs, photomicrographs, and graphs (totaling 20 printed pages) that JBJS devoted to Salter et al. in 1980, and one can’t help but wonder what this classic JBJS paper would look like if modified to fit today’s standards. But the main message is this: in spite of high-quality basic science studies using animal models, there remains a need for well-controlled studies in humans to test the efficacy of CPM after cartilage repair and other procedures.
Thomas W. Bauer, MD, PhD
JBJS Deputy Editor for Research
JBJS Classics: Open Fracture Infection Prevention
Each month during the coming year, OrthoBuzz will bring you a current commentary on a “classic” article from The Journal of Bone & Joint Surgery. These articles have been selected by the Editor-in-Chief and Deputy Editors of The Journal because of their long-standing significance to the orthopaedic community and the many citations they receive in the literature. Our OrthoBuzz commentators will highlight the impact that these JBJS articles have had on the practice of orthopaedics. Please feel free to join the conversation about these classics by clicking on the “Leave a Comment” button in the box to the left.
The common knowledge applied in managing open fractures (asepsis, irrigation and debridement, immobilization, and wound protection against infection) was obtained from the surgical experience accrued during World War I. Despite the overall improvement in outcomes from applying that knowledge, the varying severity of associated soft-tissue injuries created considerable ambiguity regarding optimal treatments during the years that followed.
”Prevention of Infection in the Treatment of 1,025 Open Fractures of Long Bones” by Ramon Gustilo and John Anderson in the June 1976 edition of JBJS classified open fractures into three types of increasing severity based on wound size, level of contamination, and osseous/soft-tissue injury. In general, more severe open fractures have a worse clinical prognosis for infection, nonunion, and other complications, although actual outcomes vary depending on numerous additional clinical factors. Also, high-energy Type III open fractures are not homogeneous, and in response to that variation, in 1984 Gustilo et al. further classified Type III open fractures into A, B, and C subtypes according to the severity of soft-tissue injury, the need for vascular reconstruction, and worsening prognosis.
However, the reliability of the Gustilo classification has been questioned in recent years. Clinical researchers have observed that the assessment of surface injuries does not always reflect deeper damage and does not account for tissue viability and tissue necrosis, which tends to develop with time after high-energy injuries. Also, a 1993 study found only moderate interobserver agreement among users of the classification. The limitless variety of injury patterns, mechanisms, and severities is almost impossible to be contained in a limited number of discrete categories.
As the management of open fractures continues to evolve, the 1976 Gustilo and Anderson treatment recommendation against primary internal fracture fixation for most Type III injuries due to high infection rates no longer represents the standard of care. Stabilization, even with internal fixation, for many of these fractures promotes healing, allows early rehabilitation, restores function, and reduces the risk of infection and malunion.
While “best practices” may have changed, the Gustilo-Anderson classification still correlates well with the risk of infection in patients with comorbid medical illnesses and other complications. It remains an easy-to-use classification system that has formed the foundation for open fracture management during the last four decades, with good but imperfect prognostic and therapeutic implications. It remains widely accepted for research and training purposes, and it provides the preferred basic language for communicating about open fractures.
Konstantinos Malizos, MD, PhD
JBJS Deputy Editor
JBJS Classics: Epiphyseal Plate Injuries
Each month during the coming year, OrthoBuzz will bring you a current commentary on a “classic” article from The Journal of Bone & Joint Surgery. These articles have been selected by the Editor-in-Chief and Deputy Editors of The Journal because of their long-standing significance to the orthopaedic community and the many citations they receive in the literature. Our OrthoBuzz commentators will highlight the impact that these JBJS articles have had on the practice of orthopaedics. Please feel free to join the conversation about these classics by clicking on the “Leave a Comment” button in the box to the left.
“Injuries Involving the Epiphyseal Plate” by Drs. Salter and Harris, published more than a half-century ago, has had a lasting impact on the field of orthopaedic surgery and on the practice of medicine in general. Every surgeon in our specialty—and almost every radiologist, pediatrician, and emergency physician—has at least a passing knowledge of the “Salter fractures.” This most enduring orthopaedic schema lives on in our practices because of its clarity of presentation, its guidance of our understanding, and its implications for treatment. It has outlasted many classifications developed before and since.
In addition to presenting the fracture classification in this classic and beautifully illustrated JBJS Instructional Course Lecture, the authors laid the groundwork with basic principles of mechanical failure and vascularity of the physis. The authors then use these principles to help explain how physeal damage may arise from misalignment, crushing, or vascular interruption. The authors elucidate these concepts further by presenting experimental studies of growth arrest, with resulting histology, and the effects of interpositional surgery. Salter and Harris then describe the famous five types of physeal injury and the clinical implications for treatment and prognosis.
Not content with generalities, the authors conclude with an extensive section describing the variations of physeal fractures in each long bone. The article is fun and inspiring to read because of the obvious fascination that the authors had in exploring the topic so completely. Rarely has experimental and clinical thought been so nicely interwoven. We don’t write that way now, and rarely if ever will we see a 36-page article in one of today’s orthopaedic journals; in many ways we are poorer for that.
Classification systems are highly cited and influential; they figure prominently in lists of top-cited orthopaedic articles. Those at the top earn this rank by their utility. This is just one of three monumental contributions by the late Dr. Salter of Toronto (along with introducing us to surgical reorientation of the acetabulum and to continuous passive motion). Please share your reactions to this classic article and its impact on you and your practice.
Paul Sponseller, MD
JBJS Deputy Editor for Pediatrics
JBJS Classics: Cervical Discectomy and Interbody Fusion
Each month during the coming year, OrthoBuzz will bring you a current commentary on a “classic” article from The Journal of Bone & Joint Surgery. These articles have been selected by the Editor-in-Chief and Deputy Editors of The Journal because of their long-standing significance to the orthopaedic community and the many citations they receive in the literature. Our OrthoBuzz commentators will highlight the impact that these JBJS articles have had on the practice of orthopaedics. Please feel free to join the conversation about these classics by clicking on the “Leave a Comment” button in the box to the left.
It is rare that an article published more than 50 years ago continues to have an impact on clinical practice today. But that is the case with “The Treatment of Certain Cervical-Spine Disorders by Anterior Removal of the Intervertebral Disc and Interbody Fusion.” What make this article so unique are the details that Drs. George Smith and Robert Robinson put into describing the procedure and the careful follow-up of their early experience with this technique.
I have had a copy of this article in my files since I was a resident at Yale, training with Wayne Southwick, who had trained with Dr. Robinson at the time this approach to the cervical spine was developed. The two key contributors to anterior cervical spine surgery back in the 1950s were Dr. Robinson and the neurosurgeon Dr. Ralph Cloward.
Dr. Robinson’s technique has the support of biomechanical principles, which makes this particular approach and bone-graft fusion construct inherently stable; hence, its continued use to this very day. However, back in the ‘50s, and even when I trained in the 1970s, hardware to stabilize the spine following discectomy was not available in the US.
The approach that these authors described is very versatile and is utilized for all sorts of anterior procedures, including removal of intervertebral discs, arthrodesis, and vertebrectomy, and it allows for doing multiple-level procedures. The technique I use today is the same one that Dr. Southwick taught me and that he learned directly from Dr. Robinson.
Dr. Robinson has had a major impact on cervical spine surgery, and it was estimated that at one time 33% to 50% of members of the Cervical Spine Research Society were trained by him, by one of his residents or fellows, or by one of their residents or fellows—Dr. Robinson’s “offspring.”
I believe this technique will continue to stand the test of time, as it has during the past half century, and will have a major influence on spine surgery well into the future.
Charles Clark, MD
JBJS Deputy Editor for Adult Reconstruction and Spine
JBJS Classics: Correlating Lumbar MRIs with Clinical Findings
Each month during the coming year, OrthoBuzz will bring you a current commentary on a “classic” article from The Journal of Bone & Joint Surgery. These articles have been selected by the Editor-in-Chief and Deputy Editors of The Journal because of their long-standing significance to the orthopaedic community and the many citations they receive in the literature. Our OrthoBuzz commentators will highlight the impact that these JBJS articles have had on the practice of orthopaedics. Please feel free to join the conversation about these classics by clicking on the “Leave a Comment” button in the box to the left.
In 1989, a group of sixty-seven asymptomatic individuals with no history of back pain or sciatica underwent magnetic resonance scans of the lumbar spine. In a landmark 1990 JBJS study, Boden et al. reported that three neuroradiologists who had no clinical knowledge of the patients interpreted the images as being substantially abnormal in 28% of the cohort (19 individuals). More specifically, a herniated nucleus pulposus was identified in 24 % of these asymptomatic subjects. These “magnetic-resonance positive” findings were more prevalent in older subjects; abnormal MRI findings were identified in 57% of those aged 60 to 80 years.
Boden et al. concluded that so many MRI findings of substantial abnormalities in asymptomatic people “emphasized the dangers of predicating a decision to operate on the basis of diagnostic tests—even when a state-of-the-art modality is used—without precise correlation with clinical signs and symptoms.”
However, despite the findings of Boden et al., during the last five years of the 1990s, Medicare claims showed a 40% increase in spine-surgery rates, a 70% increase in fusion-surgery rates, and a two-fold increase in use of spinal implants. Although spine-fusion surgery has a well-established role in treating certain spinal diseases, a 2007 systematic review of several randomized trials indicated that the benefits of fusion surgery were limited when treating degenerative lumbar discs with back pain alone. This review suggested the need for more thorough selection of surgical candidates, which was a caution also implied by Boden et al.
Although the three neuroradiologists in the Boden et al. study largely agreed on the absence or presence of abnormal findings on the MRIs, in 2014 Fu et al. reported on the interrater and intrarater agreements by four reviewers of MRI findings from the lumbar spine of 75 subjects. Even though this study used standardized evaluation criteria, there was significant variability in both interrater and intrarater agreement among the reviewers. As the Boden et al. study did 25 years ago, this study demonstrated the diagnostic limitations of MRI interpretation for lumbar spinal diseases.
In 2001, JBJS published a paper by Borenstein et al. that was a seven-year follow-up study among the same asymptomatic subjects studied by Boden et al. Borenstein et al. found that the original 1989 scans of the lumbar spine were not predictive of the future development or duration of low back pain. This led Borenstein et al. to conclude—as Boden et al. did—that “clinical correlation is essential to determine the importance of abnormalities on magnetic resonance images.”
Many important subsequent studies were inspired by the original findings of Boden et al. in JBJS. Most of them emphasize that for lumbar-spine diagnoses, an MRI is only one (albeit important) piece of data; that interpretation of MRIs is variable; and that all imaging information must be correlated to the specific patient’s clinical condition.
Several studies and national surveys indicate that approximately a quarter of US adults report having had back pain during the past 3 months, making this a common clinical complaint. But the findings of Boden, et al. and subsequent studies remind us that surgery is not always the appropriate treatment.
Daisuke Togawa, MD, PhD
JBJS Deputy Editor
JBJS Classics: Periprosthetic Bone Loss in Total Hip Arthroplasty
Each month during the coming year, OrthoBuzz will bring you a current commentary on a “classic” article from The Journal of Bone & Joint Surgery. These articles have been selected by the Editor-in-Chief and Deputy Editors of The Journal because of their long-standing significance to the orthopaedic community and the many citations they receive in the literature. Our OrthoBuzz commentators will highlight the impact that these JBJS articles have had on the practice of orthopaedics. Please feel free to join the conversation about these classics by clicking on the “Leave a Comment” button in the box to the left.
This classic investigation on periprosthetic bone loss (J Bone Joint Surg Am 1992; 74:849–863) was conducted by Tom Schmalzried in the early 1990s working in William Harris’ laboratory. Specimens from osteolytic lesions both near and far from the articular surface in 34 total hip arthroplasties were studied by plain and polarized light microscopy, as well as transmission electron microscopy.
The authors emphasized the role of activated macrophages containing micron and submicron polyethylene particles in the bone resorption evident in the areas of osteolysis. They speculated that the polyethylene-laden joint fluid migrated and penetrated far from the bearing surface to the points of least resistance. Thus, the concept of an effective joint space (i.e., all periprosthetic regions that are accessible to joint fluid and its particulate debris by the pumping action of the joint) was introduced into the orthopaedic lexicon.
Although the findings identified in this study were not necessarily new, the insights proffered by the authors radically altered our thoughts about osteolysis. Using this concept of effective joint space, subsequent investigators and innovators identified methods and designs of hip replacements to retard osteolysis by limiting the generation and spread of particulate debris.
Thus, the 1990s were marked by the development of solid acetabular cups, nonmodular monoblock components, improved liner locking mechanisms to avoid backside wear, circumferentially coated femoral stems, highly crossed-linked polyethylene to lessen abrasive wear, and metal and ceramic bearing surfaces. As appreciated by most orthopaedic residents, the article also led to a generation of questions on the Orthopaedics In-Training Exam (OITE) about the importance of macrophages in the pathogenesis of osteolysis.
Recently, some investigators speculate on a more significant mechanical effect of metal-on-metal joint fluid in causing the pseudotumors and muscle damage/necrosis that is frequently evident. Regardless of whether the primary effect of small particle-laden joint fluid is biologic or mechanical, I believe that the theory of effective joint space remains a valid anatomic concept for all arthroplasty surgeons.
Robert Bucholz, MD
JBJS Deputy Editor for Adult Reconstruction and Trauma
JBJS Classics: Bankart Repairs
Each month during the coming year, OrthoBuzz will bring you a current commentary on a “classic” article from The Journal of Bone & Joint Surgery. These articles have been selected by the Editor-in-Chief and Deputy Editors of The Journal because of their long-standing significance to the orthopaedic community and the many citations they receive in the literature. Our OrthoBuzz commentators will highlight the impact that these JBJS articles have had on the practice of orthopaedics. Please feel free to join the conversation about these classics by clicking on the “Leave a Comment” button in the box to the left.
While our current understanding of glenohumeral dislocation has its roots in antiquity, it was not until later in the twentieth century that the orthopaedic community settled on surgical repair of the capsulolabral structures as a standard treatment. Although Perthes in 1906 and Bankart in 1923 accurately and correctly identified anterior glenoid, labral, and capsular pathology as the “essential lesion” in recurrent anterior dislocations and promoted anatomic repair, other camps favored operative treatment with non-anatomic repairs including the Putti-Platt, Magnusen-Stack, and Nicola procedures. However, by the end of the twentieth century, the Bankart repair was recognized as the “gold standard.”
“The Bankart Procedure” authored by Rowe et al (J Bone Joint Surg Am 1978; 60:1–16), is a true classic paper in the orthopaedic literature. This was the first large clinical series with good follow-up to report the findings and results of the open Bankart repair. The results were almost uniformly excellent and good, with low recurrence rates, and few complications. Although the study suffers from the usual flaws of a retrospective clinical study, it set a standard and contributed to the demise of non-anatomic repairs.
More recent innovations in arthroscopy led to the development of arthroscopic Bankart labral repairs that are now the standard of care for most surgeons treating anterior glenohumeral instability. Although greater experience with arthroscopy appears to improve outcomes, failed instability repairs are not uncommon, and this has led to expanding efforts with alternative procedures such as the Latarjet coracoid transfer and remplissage. Interestingly, the contemporary focus on severe anterior glenoid bone loss and large Hill-Sachs lesions differs from the historical perspective that “The Bankart Procedure” presented in 1978. Is this the result of changes in patient pathology or expectations, or is it driven by surgeon perceptions of outcomes and the desire to innovate? I think it is a bit of both.
Among the many points that Rowe et al. make in their landmark paper is the importance of meticulous technique. Orthopaedists often gloss over such statements in the literature, but I think most would agree that anterior instability repairs, open and arthroscopic, can be technically challenging, especially for the inexperienced surgeon. Referring to the Bankart procedure, Anthony DePalma clearly stated that “the operation is difficult and should only be performed by surgeons who are familiar with the topographic anatomy” (DePalma AF. Surgery of the Shoulder. JB Lippincott Co., Philadelphia, 1950, p. 236).
Rowe et al. correctly identified the important pathologic causes of recurrent glenohumeral instability. The most recent basic and clinical research into the more complex aspects of anterior glenohumeral instability is likely to help better define the appropriate indications for alternative procedures to address these issues.
Andrew Green, MD
JBJS Deputy Editor for the Upper Extremity
JBJS Classics: ACL Graft Strength and Stiffness
Each month during the coming year, OrthoBuzz will bring you a current commentary on a “classic” article from The Journal of Bone & Joint Surgery. These articles have been selected by the Editor-in-Chief and Deputy Editors of The Journal because of their long-standing significance to the orthopaedic community and the many citations they receive in the literature. Our OrthoBuzz commentators will highlight the impact that these JBJS articles have had on the practice of orthopaedics. Please feel free to join the conversation about these classics by clicking on the “Leave a Comment” button in the box to the left.
In the classic article, “Biomechanical analysis of human ligament grafts used in knee-ligament repairs and reconstructions” (J Bone Joint Surg Am 1984; 66:344–352), now 30 years old, Noyes and colleagues studied the mechanical properties of several anterior cruciate ligament (ACL) grafts that were used at that time. Using young donors, they found that the bone-patellar tendon-bone (BPTB) graft was the only graft studied that had a maximum load in excess of the native ACL. Many of the grafts they studied—including iliotibial tract, fascia lata, and quadriceps retinaculum—had exceedingly poor strengths, which is probably why they are no longer used.
Unfortunately, the authors did not double their hamstring grafts (as is commonly done clinically) for testing, and they also used 14-mm BPTB grafts, which are much wider than commonly used clinically, so some of their comparisons may have limited clinical applicability. The authors did note several limitations to their study, including that graft strength is only one of many factors for successful ACL reconstruction, that gripping was sometimes a problem during testing, and that they only performed uni-axial testing. Nevertheless, this article set the stage for critically analyzing graft choice based upon mechanical properties.
Subsequent studies, including those by Woo, Cooper, Howell, Brown, and others, now suggest that several grafts are available that are stronger and stiffer than the native ACL, including BPTB, quadrupled hamstring (strongest and stiffest of all grafts studied), quadriceps tendon, tibialis anterior tendon, and posterior tibial tendon:
| Graft Type | Ultimate Strength(N) | Stiffness (KN/m) |
| Native ACL | 2160 | 292 |
| BPTB | 2977 | 620 |
| Quadrupled Hamstring | 4590 | 861 |
| Quadriceps Tendon | 2352 | 463 |
| Tibialis Anterior | 3412 | 344 |
| Posterior Tibialis | 3391 | 302 |
Of course, many other ACL reconstruction controversies continue to be debated, including technique, fixation, and autograft vs. allograft. But graft strength and stiffness will continue to be one of many important factors for the ACL surgeon to consider, especially if future options such as ACL augmentation and the use of synthetics and biologics become available. We welcome comments from JBJS readers.
Mark D. Miller, MD
JBJS Deputy Editor for Sports Medicine
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