Osteobiologics in foot and ankle surgery

Comparison of 4 Different Fixation Strategies for Midfoot Arthrodesis: A Retrospective Comparative Study

BACKGROUND

Midfoot arthrodesis is a common procedure performed both for arthritis and correction of deformity. The optimal fixation for midfoot arthrodesis has not been established, though numerous studies have been investigating the fixation techniques of midfoot arthrodesis. The purpose of this study was to compare the union rate of midfoot arthrodesis using 4 different fixation strategies and investigate risk factors of nonunion following midfoot arthrodesis.

METHODS

A retrospective chart review was performed for patients who underwent midfoot joint arthrodesis between January 2014 and May 2019. The rates of nonunion and postoperative complication were compared among 4 different fixation constructs: staple fixation, compression plate fixation, compression plate with lag screw fixation, and compression screw fixation. Predictors of nonunion following midfoot arthrodesis were investigated through a multivariable logistic regression analysis. A total of 95 patients (99 feet), including 240 midfoot joints were included in this study. The mean follow-up period was 78.4 weeks.

RESULTS

Overall, bony union was achieved in 86 out of 99 (86.9%) patients, which included 218 out of 240 (90.8%) midfoot joints. A significant difference in the nonunion rate according to the type of fixation construct was found (P = .011); the compression screw alone fixation construct was noted to have a significantly higher nonunion rate than other fixation constructs. Diabetes mellitus (odds ratio [OR] = 0.179 [95% CI: 0.059, 0.542]), the type of fixation construct (compression screw alone; OR =1.789 [95% CI: 1.071, 2.978]), lack of adjuvant bone graft (OR = 2.803 [95% CI: 1.081, 7.268], and postoperative nonanatomical alignment (OR = 3.937 [95% CI: 1.278, 12.126]) were identified as independent predictors of nonunion following midfoot arthrodesis.

CONCLUSION

The rate of nonunion following midfoot arthrodesis among 4 different commonly used fixation constructs was compared in this study. Risk factors of nonunion were investigated revealing that diabetes mellitus, compression screw fixation alone, lack of adjuvant bone graft, and postoperative nonanatomical alignment are independent predictors of nonunion following midfoot arthrodesis.

LEVELS OF EVIDENCE

Level III: Comparative cohort study.

Comparing Rates of Fusion and Time to Fusion in Viable Cellular Allograft and Autograft

BACKGROUND

Autograft or allograft frequently are used to enhance bone union in foot and ankle surgery. Viable cellular bone allograft uses viable cells and bone scaffolding in a gel base, but uncertainty remains around allograft's greater efficacy than autograft regarding rates of fusion (ROF) and time to fusion (TTF).

METHODS

Autograft, viable cellular allograft, and viable cellular allograft with autograft were compared in 199 forefoot, midfoot, and hindfoot arthrodeses performed over a 6-year period. Data collected from electronic medical records and radiographs were analyzed to determine ROF and TTF as well as rates of revision surgery for delayed or nonunion and compared among groups.

RESULTS

Eighty-seven patients comprised the autograft group, 81 the allograft group, and 31 the combined group. No significant differences were noted in patient demographics among the groups. No statistically significant differences in ROF were noted among the 3 groups, with 86% (75 of 87) fusion in the autograft group, 93% (75 of 81) in the allograft group, and 84% (26 of 31) in the combined group (P = .20). After conducting a multivariate analysis, we found no statistically significant difference for allograft or combined graft on TTF (P = .1379 and .2311, respectively). No significant difference was found in rate of revision surgery for nonunion, which was 1.2% (1 of 81) in the allograft group, 3.4% (3 of 87) in the autograft group, and 6.5% (2 of 31) in the combined group (P = .3).

CONCLUSION

No significant difference was found in ROF, TTF, or rate of revision surgery when comparing viable cellular allograft to autograft or combined allograft-autograft. Viable cellular allograft may be a reasonable alternative to the gold standard of autograft and should be considered an option in patients undergoing arthrodesis in foot and ankle surgery.

LEVEL OF EVIDENCE

Level III, therapeutic.

Percutaneous Harvest of Calcaneal Bone Autograft: Quantification of Volume and Definition of Anatomical Safe Zone

Bone grafting is commonly used in reconstructive foot and ankle surgery. The calcaneus provides an excellent site for graft harvest due to its rich vascularity and access to corticocancellous or strictly cancellous bone. The relatively thin soft tissue envelope makes dissection easy compared to more proximal autograft sites. In this investigation we quantified cancellous autograft volume from the calcaneus while simultaneously defining anatomical safe zones and identifying anatomical structures at risk. Nine matched-pair (18 total) fresh-frozen cadaveric below-knee limbs were utilized. All limbs were thawed at room temperature prior to the procedure. Calcaneal autograft was harvested following the senior author's (D.J.E.) technique. Bone graft was packed and quantified by podiatric medical students (B.R. and J.T.). An independent investigator (K.S.) meticulously dissected the lateral calcaneal soft tissue envelope to determine rates of neurovascular compromise. Anatomical safe zones were defined by measurements of the harvest site compared to vital anatomical structures. Cancellous autograft averaging 0.85 cc was obtained through an average cortical opening of 0.77 cm. The stab incision is approximately 2.2 cm anterior to the posterior aspect of the calcaneus and 1.6 cm superior to the inferior aspect of the calcaneus. This incision is an average 1.8 cm from the main branch of the sural nerve. No neurovascular damage was found. This study details percutaneous harvest of calcaneal autograft for use in forefoot or midfoot surgeries with an emphasis on feasibility of this additional procedure. The technique proposed is valuable based on simplicity, wide anatomic safe zone, and potential improvement of surgical outcomes.

Orthobiologics in Foot and Ankle Arthrodesis: A Systematic Review

Orthobiologics are biologically-derived materials intended to promote bone formation and union. We review evidence on effectiveness and harms of orthobiologics compared to no orthobiologics for foot and ankle arthrodesis. We searched multiple databases (1995-2019) and included clinical trials and other studies with concurrent controls, English language, and reporting patient-centered outcomes, union/time to union, costs/resource utilization, or harms. Studies were organized by orthobiologic used. We describe quality and limitations of available evidence but did not formally rate risk of bias or certainty of evidence. Most of the 21 studies included were retrospective chart reviews with orthobiologics used at surgeon's discretion for patients considered at higher risk for nonunion. Ten studies compared autologous bone graft versus no graft and 2 compared remote versus local graft with few studies of other orthobiologics. All studies reported a measure of fusion and about half reported on function/quality of life. Few studies reported harms. Due to limited reporting, we were unable to assess whether effectiveness varies by risk factors for nonunion (eg, age, gender, smoking status, obesity, diabetes) or whether orthobiologics were cost-effective. Available evidence is of poor quality with small sample sizes, inadequate reporting of risk factors for nonunion, variations in orthobiologics, surgical techniques used, and outcome assessment, and potential selection bias. Research is needed to adequately inform surgeons about benefits and harms and guide patient selection for use, or type, of orthobiologics. Careful assessment of individual patient risk for nonunion is critical prior to orthobiologic use.

Safety Profile Associated With Calcaneal Autograft Harvesting Using a Reaming Graft Harvester

BACKGROUND

Foot and ankle surgery often requires bone healing, whether in elective arthrodesis or trauma. While primary bone healing is possible, the rate of nonunion in foot and ankle surgery remains variable. The addition of autogenous bone graft can allow for higher union rates by adding to the biology at the site of bone healing. Harvesting autogenous bone graft from the calcaneus for foot and ankle surgery can be done quickly and efficiently and allow for an adequate amount of graft.

METHODS

A retrospective chart and radiographic review was performed for 1438 patients at a single center between August 1, 2015, and December 15, 2018, who underwent calcaneal autograft harvesting using a power-driven reaming graft harvester.

RESULTS

In total, 966 patients were included and evaluated for the safety and complication rate associated with the procedure. Only 1 patient (0.1%) had a major complication, and there were 14 minor complications (1.4%).

CONCLUSION

The safety profile and low complication rate of this case series demonstrate that this simple and efficient calcaneal autograft harvest technique can be considered when a small to moderate amount of autogenous bone graft is required to augment bone healing.

LEVEL OF EVIDENCE

Therapeutic level IV, case series.

Comparison and Use of Allograft Bone Morphogenetic Protein Versus Other Materials in Ankle and Hindfoot Fusions

Bone grafting is a common procedure in foot and ankle surgery. Because autogenous graft use results in comorbidity to the patient, the search has been ongoing for the ideal substitute. A novel processing technique for allograft using bone marrow, which retains many of the growth factors, has shown promise in the spinal data and early reports of foot and ankle surgery. We performed a retrospective, comparative study of patients undergoing hindfoot and ankle arthrodesis, with a total of 68 patients included. Of the 68 patients, 29 (42.65%) received a bone morphogenetic protein allograft and 39 (57.35%) did not. The patient demographics and social and medical history were similar between the 2 groups and both groups had a similar time to union (p = .581). Of the 29 patients in the bone morphogenetic protein allograft group, 3 (10.3%) experienced nonunion and 4 (13.8%) developed a complication. Of the 39 patients undergoing other treatment, 7 (17.9%) experienced nonunion and 14 (35.9%) developed a complication. The difference for nonunion was not statistically significant (p = .5). However, the difference in the overall complication rate was statistically significant (p = .04). We found that this novel bone graft substitute is safe and can be used for foot and ankle arthrodesis.

Effect of Fixation Type and Bone Graft on Tarsometatarsal Fusion

BACKGROUND:

End-stage tarsometatarsal (TMT) arthritis is commonly treated with arthrodesis of involved joints. Fixation hardware can consist of varying combinations of screws, plates, and staples with or without supplemental bone graft. There are limited data to demonstrate either superiority of a given fixation method or the impact of bone graft on fusion rates. The purpose of this study, therefore, was to determine whether nonunion rates after TMT arthrodesis were influenced by either the use of screw vs plate fixation or the addition of bone graft vs no bone graft.

METHODS:

All patients older than 18 years undergoing arthrodesis for TMT arthritis between July 1991 and July 2016 were identified retrospectively. Exclusion criteria included less than 12 months follow-up, prior midfoot surgery, any added procedure beyond TMT arthrodesis using plates or screws, and acute foot trauma. All patients with radiographic or clinical nonunion, including those requiring revision surgery, were identified. Demographic data and associated risk factors were recorded via chart and radiographic image review. Eighty-eight patients (88 feet, mean follow-up: 75.1 ± 51.4; range, 12-179), with a total of 189 joints and who met enrollment criteria were treated by 9 different surgeons with arthrodesis.

RESULTS:

The overall nonunion rate was 11.4%. Significant independent risk factors associated with nonunion were (1) arthrodesis using plate fixation with all screws through the plate (odds ratio [OR], 6.2; 95% confidence interval [CI], 1.8-21.3; P = .004), (2) smoking during the perioperative period (OR, 7.9; 95% CI, 2.1-30.2; P = .002), and (3) postoperative nonanatomic alignment (OR, 11.2; 95% CI, 2.1-60.8; P = .005). Bone graft utilization was found to significantly lower the rate of nonunion (OR, 0.2; 95% CI, 0.1-0.6; P = .006).

CONCLUSION:

Isolated plate fixation, smoking, and postoperative nonanatomic alignment appear to significantly increase the rate of nonunion among patients undergoing TMT arthrodesis for midfoot arthritis. Concomitant use of autogenous bone graft significantly decreased this risk.

LEVEL OF EVIDENCE:

Level III, retrospective comparative study.