Weight-Bearing CT: An Incremental Step in Addressing Posttraumatic Ankle Arthritis
Orthopaedic surgeons recognize that an intra-articular fracture of the distal tibia (pilon fracture) is the worst actor when it comes to the sequela of posttraumatic ankle osteoarthritis. Despite decades of focusing on surgical techniques that yield the best-looking postoperative radiographs, we have come to realize that, to reduce the risk of subsequent arthritis, limiting the extent of the surgical approach may be as important as achieving the “perfect” articular reduction. Slowly we have come to understand that articular cartilage damage from the injury (and in some instances exacerbated by overaggressive surgical dissection) is as big a factor as the bone injury in terms of postoperative joint-space narrowing and its associated ankle stiffness and pain.
Thankfully, the orthopaedic trauma community is making strides toward new biologic, mechanical, and rehabilitative interventions that have the potential to limit this articular narrowing. But to meaningfully evaluate the effectiveness of these strategies, we need not only validated patient-oriented functional outcome measures, but also more reliable and reproducible ways to assess the joint-space narrowing.
In the May 6, 2020 issue of The Journal, Willey et al. report on a standardized technique using weight-bearing computed tomography (WBCT), which yields a 3D assessment of the postoperative joint space with the ankle in a loaded, functional position (see Figure above). When this technique was applied to 20 patients (mean age of 44 years) with a partial or complete articular pilon fracture 6 months after surgical treatment, the authors found significantly less tibiotalar joint space in the injured ankle compared with the uninjured ankle. Interrater correlation and test-retest data indicated that this method has good measurement reliability and reproducibility.
Any safe, reliable, and reproducible measure of early joint-space narrowing after pilon fracture surgery is an important incremental step in designing clinical trials that will assess new interventions designed to preserve postoperative joint space—and hopefully reduce the incidence of posttraumatic ankle arthritis. Willey et al. have demonstrated the usefulness of WBCT as such a modality.
Marc Swiontkowski, MD
JBJS Editor-in-Chief
What’s New in Sports Medicine 2020
Every month, JBJS publishes 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 OrthoBuzz summaries of these “What’s New” articles. This month, co-author Christopher Y. Kweon, MD selected the 5 most clinically compelling findings from the 40 studies summarized in the April 15, 2020 “What’s New in Sports Medicine.”
ACL Graft Choice
—A randomized controlled trial (RCT) comparing bone-tendon-bone autograft, quadrupled hamstring tendon autograft, and double-bundle hamstring autograft for ACL reconstruction in young adults found the following:
- No between-group differences in patient-reported quality-of-life scores at 5 years
- Significantly higher rates of traumatic graft reinjuries in the hamstring-tendon and double-bundle groups
- Relatively low (37%) return to preinjury level of activity for the entire population, with no significant between-group differences
Meniscal Repairs with Bone Marrow Venting
—A double-blinded RCT1 of patients with complete, unstable, vertical meniscal tears compared isolated meniscal repair to meniscal repair with a bone marrow venting procedure (BMVP). Meniscal healing, as assessed with second-look arthroscopy at a mean of 35 weeks, was 100% in the BMVP group and 76% in the control group (p = 0.0035). Secondary pain and function measures at 32 to 51 months were also better in the BMVP group.
Rotator Cuff Repair Rehab
—A multisite RCT2 among >200 patients who received arthroscopic repair of a full-thickness rotator cuff tear compared standard rehabilitation (patients wore a sling at all times except when performing prescribed exercises) and early mobilization (patients wore a sling only when needed for comfort). Early mobilizers showed significantly better forward flexion and abduction at 6 weeks, but no subjective or objective differences (including retear rate) were found at any other time points.
Remplissage for Anterior Shoulder Instability
—A systematic review3 of studies investigating arthroscopic Bankart repair with and without remplissage found significantly higher instability-recurrence rates with isolated Bankart repair. Overall, the addition of remplissage appears to yield better patient-reported function scores compared with isolated Bankart repair alone.
Syndesmotic Ankle Injuries
—A meta-analysis of 7 RCTs (335 patients)4 comparing dynamic versus static fixation for syndesmotic injuries of the ankle found that the overall risk of complications was significantly lower in the dynamic fixation group. Reoperation rates were similar in the two groups, but implant breakage or loosening was reduced with dynamic fixation devices. Compared with static fixation, the dynamic fixation group also had higher AOFAS scores and lower VAS scores at various time points.
References
- Kaminski R, Kulinski K, Kozar-Kaminska K, Wasko MK, Langner M, Pomianowski S. Repair augmentation of unstable, complete vertical meniscal tears with bone marrow venting procedure: a prospective, randomized, double-blind, parallel-group, placebo-controlled study. Arthroscopy.2019 May;35(5):1500-1508.e1. Epub 2019 Mar 20.
- Sheps DM, Silveira A, Beaupre L, Styles-Tripp F, Balyk R, Lalani A, Glasgow R, Bergman J, Bouliane M; Shoulder and Upper Extremity Research Group of Edmonton (SURGE). Early active motion versus sling immobilization after arthroscopic rotator cuff repair: a randomized controlled trial. Arthroscopy.2019 Mar;35(3):749-760.e2.
- Lazarides AL, Duchman KR, Ledbetter L, Riboh JC, Garrigues GE. Arthroscopic remplissage for anterior shoulder instability: a systematic review of clinical and biomechanical studies. Arthroscopy.2019 Feb;35(2):617-28. Epub 2019 Jan 3.
- Grassi A, Samuelsson K, D’Hooghe P, Romagnoli M, Mosca M, Zaffagnini S, Amendola A. Dynamic stabilization of syndesmosis injuries reduces complications and reoperations as compared with screw fixation: a meta-analysis of randomized controlled trials. Am J Sports Med.2019 Jun 12. [Epub ahead of print].
Treating Transitional Ankle Fractures: Best Evidence Yet
Transitional fractures of the ankle in adolescents are related to torsional injuries that occur around the time that the distal tibial physis begins to close. In recent years, treatment has moved toward screw fixation when the intra-articular fracture gap in Salter type III (Tillaux) and type IV (triplane) fractures is between 1 mm and 2 mm. The rationale for operative treatment has been that intra-articular fracture gaps should be completely reduced, particularly in younger patients, to limit the long-term risk of post-traumatic osteoarthroses. However, evidence supporting the wisdom of surgical intervention has been thin at best. (See Clinical Summary on Triplane Ankle Fractures.)
In the April 15, 2020 issue of The Journal, Lurie et al. report on a retrospective analysis of 34 patients with a triplane fracture and 23 patients with a Tillaux fracture, all of which had 2 mm to 5 mm of articular displacement. Among those 57 patients, 34 were treated with surgery and 23 with closed reduction and casting.
Based on regression analysis, nonoperative treatment, a larger intra-articular gap after closed reduction, and the presence of a grade-III complication were associated with worse functional outcomes at a mean follow-up of 4.5 years. Patients who were treated nonoperatively and had a gap ≤2.5 mm had significantly better functional scores than similar patients with a gap >2.5 mm. From this data, the authors conclude that “surgical management of these injuries likely conveys the greatest functional benefit when the intra-articular gap exceeds 2.5 mm.”
This study has the usual issues of treatment and detection bias inherent in retrospective reviews, and the measurement of fracture gaps, even with the CT scans these authors used, is not always reliable at this level of precision. Nevertheless, this data from Lurie et al. is the best we have to date to indicate that the so-called “2-mm rule” of nonoperative management of transitional ankle-fracture gaps ≤2 mm probably makes sense in most clinical situations.
Marc Swiontkowski, MD
JBJS Editor-in-Chief
Subtalar Joint Compensation after Ankle Fusion
Ankle fusion continues to be a predictable treatment for degenerative tibiotalar arthritis. It improves both pain and function from primary osteoarthritis and degeneration related to chronic instability or trauma. JBJS has published several recent studies demonstrating that the outcomes of fusion compare favorably with those of total ankle replacement, particularly in higher-demand patients. (See, for example, Effectiveness and Safety of Ankle Arthrodesis Versus Arthroplasty and Outcomes of Total Ankle Replacement, Arthroscopic Ankle Arthrodesis, and Open Ankle Arthrodesis for Isolated Non-Deformed End-Stage Ankle Arthritis.)
Many clinicians have wondered why outcomes after ankle arthrodesis are typically so much better than those after arthrodesis of other mobile joints. In the April 1, 2020 issue of The Journal, Lenz et al. provide an answer. Using dual fluoroscopy integrated with 3-D CT, the authors compared the subtalar motion of the surgically fused ankle in 10 patients with the motion of the untreated, asymptomatic side. The findings strongly suggest that compensatory increased plantar flexion of the subtalar joint allows improved function following successful arthrodesis. The authors found that this increased motion occurred during both normal plantigrade ambulation and bilateral heel raises.
Clinicians can use this important information to explain to patients who are deciding between ankle arthrodesis and arthroplasty how fusion can not only improve pain, but can also result in good functional range of motion. On the other hand, the authors surmise that the compensatory increase in subtalar joint plantar flexion may explain the reported increased risk of future subtalar osteoarthritis in surgically fused ankles. However, to answer that question, we’ll need larger, longitudinal clinical studies that evaluate the relationship between the compensatory post-fusion subtalar kinematics discovered by Lenz et al. and radiographic findings and patient-reported pain and function.
Marc Swiontkowski, MD
JBJS Editor-in-Chief
Implant Prices are Main Cost Driver in Joint Replacements
Orthopaedic surgeons have long been aware of the role that implant prices play in the total cost of care for arthroplasty procedures, but methodical breakdowns of implant costs in relation to the cost of other aspects of care have generally been lacking. In the March 4, 2020 issue of The Journal, Carducci et al. detail the impact of implant costs on the total cost of care in a study of 6 lower- and upper-extremity arthroplasty types performed at a single, high-volume orthopaedic specialty hospital.
Using a uniform method called time-driven activity-based costing, the authors calculated the total costs of >22,200 inpatient primary total joint arthroplasties, and then broke down those total costs by categories, including implant price and personnel costs. It was no surprise that, as a percentage of total cost, implant costs were highest for low-volume surgeries (as high as 65% for total ankle arthroplasty) and lowest for high-volume procedures (e.g., 40% for total knee arthroplasty). Nevertheless, across the board, implant price was the most expensive component of total cost.
Implant prices are individually negotiated between a hospital and an implant supplier and are usually protected by nondisclosure agreements, so the data from this investigation may not match up with data from any other institution. Unfortunately, the future of implant-cost research will be tied to the complex issue of return-on-investment for implant-manufacturer stockholders as it relates to negotiations with individual hospitals and health systems.
The profound impact of implant price on the total cost of all the joint arthroplasties studied by Carducci et al. also begs the questions as to how “generic” implants (those not manufactured by the major orthopaedic producers) will ultimately influence the market—and whether “branded” implants, with their 30% to 50% markups, provide any functional benefit for patients. We will need further well-designed research to address those questions.
Marc Swiontkowski, MD
JBJS Editor-in-Chief
Total Ankle Arthroplasty: Maybe Not as Finicky as We Thought?
As the orthopaedic community continues to solve complex issues related to joint replacement, it has become apparent that deformity correction and component positioning are keys to long-term success. In terms of hip, knee, and shoulder arthroplasty, we have progressed throughout the last 50 years with improved functional outcomes and component longevity. Elbow arthroplasty development has lagged somewhat because indications for that procedure are much less common.
Meanwhile, total ankle arthroplasty (TAA) experienced a short-lived decade of enthusiasm in the late 1970s and early 1980s before it became apparent that improved component designs and surgical techniques were needed. Progress with TAA stalled until the late 1990s, but TAA has now become more predictable, and several successful designs are available with reasonable revision rates demonstrated during 10-plus years of follow-up. As with all arthroplasties, component alignment in TAA is critical, and we have therefore assumed that significant preoperative frontal plane deformity is a contraindication for this procedure.
However, in the December 18, 2019 issue of The Journal, Lee et al. challenge that assumption with midterm follow-up data on 146 TAAs that suggest patients with frontal plane deformities >20° should not necessarily be disqualified from having this procedure. In this study, prior to surgery, 107 ankles had moderate frontal plane deformity (5° to <15° of varus or valgus) and 41 ankles had severe deformity (>20° to 35° of varus or valgus). The authors found no difference between these groups in terms of functional outcomes, complications, or implant survival at a mean follow-up of 6 years. Lee et al. conclude that frontal malalignment >20° in patients with end-stage ankle osteoarthritis may not be a contraindication to proceeding with TAA. However, the authors emphasize that concomitant realignment procedures at the time of index arthroplasty (including ligament releases and corrective osteotomies) were much more common in the severe group.
These findings need confirmation from other groups and with longer-term follow-up so that data from lower-volume surgeons can be analyzed and later complications can be investigated. Still, it just may be that ankle arthroplasty is not as finicky as we have been thinking.
Marc Swiontkowski, MD
JBJS Editor-in-Chief
Negative Findings from Level-I Trial Still a Step Forward
Donor-site morbidity from harvesting autologous bone graft has driven the decades-long search for a substitute that performs at least as well as a patient’s own bone. Much of the clinical research on donor-site morbidity is flawed by detection bias, but other factors such as operating-room time and expense are still driving the search for the ideal substitute for autologous bone. Still, the discovery of an ideal bone-graft substitute continues to be elusive.
In The November 6, 2019 issue of The Journal, Myerson et al. report findings from a Level-I trial that investigated the use of adipose-derived cellular bone matrix (ACBM) as a graft substitute in patients undergoing subtalar arthrodesis. Among 57 patients who received autograft and 52 who received ACBM, the substitute delivered lower fusion rates as determined by both CT and plain radiographic/clinical evaluations at 6 months. In addition, patients treated with autologous bone graft had lower rates of serious adverse events.
I commend the authors and funders (AlloSource) of this well-designed clinical trial for reporting these negative results, because it is often just as important to know what doesn’t work as what does. (This manuscript was submitted even after AlloSource decided to halt further production of its ACBM product in 2017.) Such transparent reporting saves other investigators and graft substitute-focused companies from going down similar avenues of investigation. Perhaps even more importantly, publishing negative results such as this might save patients from undergoing procedures with similar formulations that would probably have minimal chance of helping and could do harm.
By contributing to the scientific “process of elimination,” this study brings us one step closer to the identification of a worthy substitute for autologous bone graft.
Marc Swiontkowski, MD
JBJS Editor-in-Chief
Subtalar Joint’s Middle Facet Yields Insight into Flatfoot
Many foot and ankle surgeons would relish a simple measurement made from a readily available imaging modality to help detect whether patients with adult acquired flatfoot deformity (AAFD) are at high risk for progressive collapse—and to help them with surgical planning. According to the findings from a case-control study by de Cesar Netto et al. in the October 16, 2019 issue of The Journal of Bone & Joint Surgery, that wish may soon be realized.
The authors made standing, weight-bearing computed tomography (CT) scans of 30 patients with stage-II AAFD (mean age of 57.4 years) and 30 matched controls (mean age of 51.8 years). From those images, 2 fellowship-trained surgeons, who were blinded regarding the patient cohorts, measured the amount of subluxation (percentage of uncoverage) and the incongruence angle of the middle facet of the subtalar joint in the coronal plane. The authors found substantial to almost perfect intraobserver and interobserver reliability for both measurements.
Based on these middle-facet measurements, the mean value for joint uncoverage in patients with AAFD was 45.3% compared with 4.8% in controls. Similarly, the mean incongruence angle in the AAFD group was 17.3° in the AAFD group and 0.3° in controls. Further analysis led the authors to conclude that “an incongruence angle of >8.4° and an uncoverage percentage of 17.9% were found to be highly diagnostic for symptomatic stage-II AAFD.”
De Cesar Netto et al. say the biomechanics of the subtalar joint made focusing on the middle facet a sensible approach, and they attributed the high reliability of the measurements to the relatively simple anatomy of the middle facet. Still, because clinical outcomes were not assessed in this study, the role of the middle facet as a marker of peritalar subluxation and a tool for deformity correction in AAFD patients needs further investigation in prospective, longitudinal studies.
Step Monitors Yield New Insight into Ankle Surgery Outcomes
Patients considering surgery for end-stage ankle arthritis often ask which treatment—arthroplasty or arthrodesis—will help the most. Findings from various studies attempting to answer that complex question have been equivocal. In the July 3, 2019 issue of The Journal of Bone & Joint Surgery, Shofer et al. inject some objective data gleaned from step counters worn by 234 patients into this predominantly subjective question.
All patients were treated with either arthroplasty (n = 145) or arthrodesis (n = 89). Their step activity was measured with a StepWatch 3 Activity Monitor preoperatively and at 6, 12, 24, and 36 months postoperatively. In both groups combined, step counts during “high activity” (>40 steps per minute) increased by 46% over 36 months. At 6 months, the mean high-activity step improvement was 194 steps in the arthroplasty group, compared with a mean decline of 44 steps for the arthrodesis group. However, by 36 months after surgery, the between-group differences in high-activity steps had disappeared.
The authors also analyzed associations between the objective step results and 3 patient-reported outcomes (the Musculoskeletal Function Assessment and the SF-36 physical function and pain scores). Unlike the patient-reported scores, which improved dramatically in the first 6 months and then plateaued, improvements in step activity increased gradually throughout the 3-year follow-up.
The authors emphasized that during the first 12 postoperative months, the arthrodesis patients had little or no improvement in step activity, but at 3 years there were no significant differences between arthrodesis and arthroplasty patients. These findings suggest that, in this clinical scenario, an individual patient’s expectations with the pace of improvement may be a suitable topic during shared decision making conversations.
This study does not entirely reconcile previously equivocal findings regarding arthroplasty-versus-arthrodesis, but it does emphasize the substantial and sustained activity benefits that patients in both groups receive. Shofer et al. conclude that objective measurements from wearable technology “may complement patient-reported outcomes” in future longitudinal outcome studies of many orthopaedic treatments.
July 2019 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 July 2019, JBJS and OrthoBuzz readers will have open access to the JOSPT article titled “Effectiveness of Foot Orthoses Versus Corticosteroid Injection for Plantar Heel Pain: The SOOTHE Randomized Clinical Trial.”
Among 103 patients with plantar heel pain who received either arch-contouring foot orthoses or a single ultrasound-guided corticosteroid injection, the injection was more effective at week 4, but the foot orthoses were more effective at week 12. But the authors note that “the differences between the interventions did not meet the previously calculated minimal [clinically] important difference value of 12.5 points.”
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