Fresh-frozen Femoral Head Research Articles

Arthroscopic-Assisted Reduction of Depressed Lateral Tibial Plateau Fracture Using Precision Drill Guide and Fresh-Frozen Femoral Head Allograft

In the patient with osteoporosis, tibial plateau fractures can occur after high-energy trauma or low-energy trauma. Arthrosis will rapidly progress if the depressed articular surface is left untreated. Therefore, the depressed articular surface should be treated by anatomical reduction. This Technical Note describes an arthroscopic-assisted reduction depressed lateral tibial plateau fracture using a precision drill guide and fresh-frozen femoral head allograft.

Biologic Augmentation of Tibiotalocalcaneal Arthrodesis With Allogeneic Bone Block Is Associated With High Rates of Fusion.

The orthopaedic conditions and systemic comorbidities that occur in patients who require bone block tibiotalocalcaneal (TTC) arthrodesis have made this procedure associated with a higher-than-normal risk of nonunion, graft collapse, hardware failure, and amputation. Here, we present a novel approach to bone block TTC arthrodesis using adjunctive osteoinductive agents and a prolonged course of protected weightbearing to assess if we could improve on historical outcomes. We also evaluated the efficacy of a vascularized medial femoral condyle (MFC) free flap to augment TTC arthrodesis. Fourteen adult patients underwent bone block TTC arthrodesis biologically augmented with fresh-frozen femoral head allograft, bone marrow aspirate concentrate, and demineralized bone matrix cortical fibers. Three patients with soft tissue defects underwent vascularized reconstruction with an MFC free flap. Radiographic union, the Foot Function Index (FFI), and PROMIS pain interference (PI), and physical function (PF) scores were assessed at follow-up. TTC fusion was documented on plain radiograph in 13 of 14 patients (92.9%) and CT in 10 of 11 patients (90.9%). Mean time to fusion was 183.2 ± 83.2 days. One patient (7.1%) experienced nonunion and persistent infection requiring amputation. Patients who underwent vascularized bone grafting had significantly shorter time to fusion (112.3 ± 31.7 days vs 204.4 ± 82.7 days, P = .05). Patient-reported outcomes revealed mild to moderate pain and dysfunction after 1 year (mean FFI = 41.0% ± 23.1%, PROMIS PI = 58.3 ± 1.8, PROMIS PF = 39.0 ± 2.2). In this relatively small series, the biologic augmentation of bone block TTC arthrodesis with osteoinductive agents and protective weightbearing resulted in excellent rates of fusion, modest pain, and preserved function of the lower extremity in almost all those treated. Osseous healing appears to be enhanced and accelerated with application of an MFC flap. We believe that this approach offers a viable salvage option for these challenging clinical problems. Level IV, case series.

Novel bone grafting technique in stand-alone ALIF procedure combining allograft and autograft (\u2018Northumbria Technique\u2019)\u2014Fusion rate and functional outcomes in 100 consecutive patients

IntroductionSuccessful ALIF surgery depends upon achieving solid fusion, whilst avoiding significant complications. Herein, we present the ‘Northumbria Technique’ of combining allograft with autograft in order to achieve solid interbody fusion.Materials and MethodsA single-surgeon series of 100 consecutive patients undergoing stand-alone ALIF from 2016 to 2019 was studied. All had percutaneously harvested iliac crest bone graft (ICBG) dowels inserted into blocks of fresh frozen femoral head (FFFH) allograft, which were then inserted into the ALIF cages. Patients had dynamic radiographs at 4 months, CT at 6 months, and patient reported outcome measure scores (PROMS) throughout.ResultsOne hundred patients (average age 44.8 years) were followed-up for an average of 29.1 months. Ninety-four (94%) patients were assessed as having fused on both CT and radiographs by an independent Radiologist. Three (3%) patients had abolition of movement on radiographs, but either lacked a CT scan or failed to meet Williams criteria for fusion. Two patients failed to attend for any imaging, so were considered not fused, and one patient had no evidence of fusion in either modality. There was a significant improvement in all PROMS. There were no intra-operative complications, and one patient had transient donor-site pain.ConclusionsThe newly described ‘Northumbria Technique’ utilises the osteoconductive characteristics of the FFFH allograft, as well as the osteoinductive and osteogenic properties of the ICBG autograft. It gives high fusion rates (94–97%) and statistically significant improvements in PROMS, whilst avoiding the complications of harvesting a large amount of autograft and the huge costs of using synthetic agents.

Analysis of the Disposal Rate of Fresh Frozen Femoral Head in the Bone Bank of a Single Hospital

Analysis of the Disposal Rate of Fresh Frozen Femoral Head in the Bone Bank of a Single Hospital

Biologic Augmentation of Tibiotalocalcaneal Arthrodesis with Autologous Bone Block is Associated with High Rates of Fusion

Category:Ankle; HindfootIntroduction/Purpose:Tibiotalocalcaneal (TTC) arthrodesis is an established salvage procedure for severe deformities of the hindfoot. Despite its prevalence, end-stage pathology, systemic comorbidities, and the physical demands of surgery often precipitate unsuccessful outcomes, with nonunion rates as high as 85% in medically complex patients. Given the considerable morbidity associated with TTC arthrodesis, there has been recent interest in maximizing the physiologic potential of fusion by means of surgical technique, osteoinductive and osteoconductive biological agents, and vascularized bone flaps. Here, we present a novel approach to TTC arthrodesis using femoral head allograft bone block, bone marrow aspirate, and demineralized bone matrix (DBM) in the absence of tourniquet. Additionally, we explore the role of the medial femoral condyle (MFC) free flap as a reconstructive adjunct to arthrodesis.Methods:The sample consisted of 14 patients presenting to a tertiary care facility for reconstructive limb salvage. TTC arthrodesis was performed without tourniquet and biologically augmented with fresh-frozen femoral head allograft, pelvic bone marrow aspirate, and DBM. Three patients with severe soft tissue defects also underwent vascularized osseous reconstruction with MFC free flap. Recovery protocol included three months of prolonged non-weightbearing mechanical stabilization followed by conversion to weightbearing AFO boot for one year. Post-operative plain radiographs and computed tomography (CT) scans were assessed for fusion at regular follow-up. After fusion, participants completed a survey on patient-reported outcomes, which included the modified Foot Function Index (FFI) and Patient-Reported Outcomes Measurement Information System (PROMIS) scales for pain and physical function.Results:Successful TTC fusion was documented on plain radiograph in 13 patients (92.9%) and confirmed via CT in 10 patients (90.9%). The mean time-to-fusion was 183.2 +- 83.2 days. One patient (7.1%) failed to achieve fusion and underwent amputation secondary to infectious wound complications. Patients who underwent vascularized bone grafting had more robust healing and significantly shorter time-to-fusion (112.3 +- 31.7 days vs. 204.4 +- 82.7 days, p = 0.05). The mean patient-reported FFI score was found to be 40.96% +- 23.08%, indicating mild-to-moderate impairment in foot function. Similarly, PROMIS data revealed that patients who underwent TTC arthrodesis had a pain T-score of 58.34 (z = 0.83) and a physical function T-score of 39.00 (z = - 1.10), corresponding to mild pain and moderate impairment, respectively.Conclusion:We sought to biologically optimize the osteoinductive and osteoconductive potential of TTC arthrodesis using femoral head allograft bone block, bone marrow aspirate, and DBM in the absence of tourniquet. This approach resulted in excellent rates of fusion with minimal pain and preserved function of the lower extremity. Osseous healing was significantly enhanced by MFC flap in patients with soft tissue defects. We, therefore, recommend biologic augmentation of TTC arthrodesis as a viable salvage option for patients facing amputation or other undesirable outcomes.

The biological acetabular reconstruction with bone allografts in hip revision arthroplasty.

Reconstructions in case of acetabular bone loss in hip revision arthroplasty are challenging. A few techniques have been proposed, with inconstant outcomes. Biological reconstructions using bone allografts may address the acetabular bone loss and restore the hip anatomy. Aim of this work was the description of the surgical technique and the evaluation of the outcomes using a regional arthroplasty register. Minor or massive bone allografting was performed in hip revision arthroplasties in a tertiary center. Bulk allografts were used in severe acetabular bone losses. Fresh-frozen femoral heads were impacted in the bone cavity and porous cups were implanted; multihole sockets were used when necessary. In DeLee A zone, no grafts were used in order to reduce overstress graft resorption. The results were evaluated using a regional arthroplasty register, and a comparison with revisions without bone grafts was performed investigating re-revision rates and reasons for further revisions. At 10years, acetabular revisions with bone allografts achieved a similar survival rate than revisions without bone grafts. The re-revisions occurred more frequently in revisions without bone allografts (10.8 vs. 9.7%). In the allograft cohort, septic loosening was lower (0.3 vs. 2.6%), whereas a higher rate of aseptic cup loosening was experienced (2.7 vs. 1.4%). Bone allografts may provide a good restoration of the acetabular bone stock and the hip biomechanics. Septic loosening does not seems a major concern, whereas a higher rate of aseptic cup loosening should be expected when bone grafts are used.

Wrist Arthrodesis With Femoral Head Structural Allograft After Failed Total Wrist Arthroplasty.

The failed total wrist arthroplasty represents a challenging reconstructive problem for the upper extremity surgeon. Bone loss, poor bone quality, and soft tissue defects all present technical challenges when considering revision procedures. Our purpose is to describe a technique for wrist arthrodesis after failed total wrist arthroplasty utilizing fresh-frozen femoral head allograft and dorsal plate fixation. We describe a simple method of allograft preparation for this procedure, as graft preparation and implantation can be time consuming and technically challenging.

Femoral Head Allograft for First Metatarsal Phalangeal Joint Fusion Using a Reamer Technique to Limit Graft Length

The use of interpositional bone grafting for arthrodesis of the first metatarsophalangeal joint can be a technically challenging procedure. A fresh-frozen femoral head allograft can provide an appropriate graft for lengthening and ultimate fusion. It has been well-documented in published studies that larger grafts at this site increase the risk of complications. When the joint is resected in a “square” fashion, length is actually lost from the first metatarsal head. We present a technique using a reamer applied to 1 side of the graft and the first metatarsal head in a “cup-and-cone” fashion, thereby limiting the total length of the actual graft size. This technique allows for easy positioning and lengthening, increasing the chance of graft incorporation at the fusion sites.

Cost analysis of fresh-frozen femoral head allografts: is it worthwhile to run a bone bank?

To assess the sustainability of our institutional bone bank, we calculated the final product cost of fresh-frozen femoral head allografts and compared these costs with the use of commercial alternatives. Between 2007 and 2010 all quantifiable costs associated with allograft donor screening, harvesting, storage, and administration of femoral head allografts retrieved from patients undergoing elective hip replacement were analysed. From 290 femoral head allografts harvested and stored as full (complete) head specimens or as two halves, 101 had to be withdrawn. In total, 104 full and 75 half heads were implanted in 152 recipients. The calculated final product costs were €1367 per full head. Compared with the use of commercially available processed allografts, a saving of at least €43 119 was realised over four-years (€10 780 per year) resulting in a cost-effective intervention at our institution. Assuming a price of between €1672 and €2149 per commercially purchased allograft, breakeven analysis revealed that implanting between 34 and 63 allografts per year equated to the total cost of bone banking.

The outcome of scapulothoracic arthrodesis using cerclage wires, plates, and allograft for facioscapulohumeral dystrophy

Scapulothoracic arthrodesis is a recognized treatment for impaired shoulder function in patients with facioscapulohumeral dystrophy (FSHD) and is traditionally performed with autograft. The purpose of the study was to report our experience with scapulothoracic arthrodesis in patients with FSHD using allograft, rather than autograft, with particular respect to the effect of fusion on preoperative and postoperative Disabilities of the Arm, Shoulder and Hand (DASH) scores; forced vital capacity (FVC); and complications. The early results of 14 consecutive scapulothoracic arthrodeses in FSHD patients with cerclage wires, plates, and allograft (fresh-frozen femoral heads) are reported. DASH scores were recorded preoperatively and 6 months postoperatively. Preoperative and 6-month FVCs were compared. The surgical technique is described. Eleven patients underwent 14 fusions. The mean follow-up period was 29 months (range, 6-50 months). Forward flexion improved from 70° to 115° (P = .001) and abduction from 68° to 109° (P = .007). The DASH score improved from 48 points to 34 points (P = .005). FVC decreased from 98% to 92% of predicted (P = .021), although this was not clinically significant. One patient required revision for nonunion, and metalwork was removed in 5 scapulae. A postoperative chest infection developed in 1 patient and a pleural effusion in another. One brachial plexus palsy occurred, which had almost completely resolved by 27 months postoperatively. Scapulothoracic arthrodesis can be performed successfully with allograft. The nonunion and complication rates are similar to those in the existing literature. A small decrease in FVC does occur but not to a clinically significant level.

Les allogreffes de têtes fémorales congelées intercorporéales vertébrales permettent un taux de fusion élevé sans enfoncement de la greffe

Summary Background Circumferential lumbar spinal fusion is widely used to increase fusion rate, but little data is available using fresh-frozen femoral head allograft (FFFHA) as a structural interbody graft alternative. Hypothesis Circumferential lumbar arthrodesis using FFFHA as interbody graft material could be an alternative to achieve interbody fusion without graft subsidence. Methods A retrospective review of 47 patients (56 levels) treated with lumbar circumferential fusion using FFFHA as interbody material. Consolidation was independently assessed by the two authors using a 3-type scale; interbody bone graft subsidence was also evaluated. Results Forty-four of the 47 patients (93.6%), and 53 of the 56 levels (94.6%) obtained consolidation, without differences between smokers and nonsmokers. Three levels (in three patients) did not fuse; one of them (2.1%) required revision. No patient presented graft dislodgment, signs of infection or graft subsidence at the last follow-up. Discussion FFFHA use as lumbar interbody graft in circumferential arthrodesis exhibited a 94% fusion rate, without graft subsidence. FFFHA may be considered a valid alternative to achieve interbody fusion. Level of evidence Level IV. Retrospective study.

Fresh-frozen femoral head allograft as lumbar interbody graft material allows high fusion rate without subsidence

Circumferential lumbar spinal fusion is widely used to increase fusion rate, but little data is available using fresh-frozen femoral head allograft (FFFHA) as a structural interbody graft alternative. Circumferential lumbar arthrodesis using FFFHA as interbody graft material could be an alternative to achieve interbody fusion without graft subsidence. A retrospective review of 47 patients (56 levels) treated with lumbar circumferential fusion using FFFHA as interbody material. Consolidation was independently assessed by the two authors using a 3-type scale; interbody bone graft subsidence was also evaluated. Forty-four of the 47 patients (93.6%), and 53 of the 56 levels (94.6%) obtained consolidation, without differences between smokers and nonsmokers. Three levels (in three patients) did not fuse; one of them (2.1%) required revision. No patient presented graft dislodgment, signs of infection or graft subsidence at the last follow-up. FFFHA use as lumbar interbody graft in circumferential arthrodesis exhibited a 94% fusion rate, without graft subsidence. FFFHA may be considered a valid alternative to achieve interbody fusion. Level IV. Retrospective study.

Comparison of the efficiency of different antibiotic irrigation solutions in decontamination of allografts contaminated with Staphylococcus aureus

The purpose of this study was to investigate the local antibacterial efficacy of saline, rifampicin, gentamicin, high-concentration fusidic acid and low-concentration fusidic acid in the decontamination of allografts contaminated with Staphylococcus aureus. Fifty-five sterile, fresh-frozen femoral heads obtained from the bone bank were contaminated with methicillin-sensitive ATCC 25923 Staphylococcus aureus. Samples were divided into groups and debrided with high-pressure (80 psi) pulse lavage using a saline, rifampicin irrigation solution (50 mg/l), gentamicin irrigation solution (50 mg/l) and low- (50 mg/l) or high-concentration (500 mg/l) fusidic acid irrigation solution for 30 seconds from a distance of 10 cm. After irrigation, allografts were incubated in the culture and developed colonies were counted. Mean±standard deviation (min-max) values were calculated. The differences between the four irrigation groups were evaluated using the Kruskal-Wallis variance analysis and groups were compared two at a time using the post-hoc Mann-Whitney U test. No colonization was detected with the exception of one allograft in the rifampicin irrigation group. The gentamicin irrigation group had similar results as the high-concentration fusidic acid irrigation group and both results were superior to those of the saline and low-concentration fusidic acid irrigation groups (p=0.010 and 0.004, respectively). The low- and high-concentration fusidic acid irrigation groups were similar and were not shown to have superior results than saline irrigation group. Rifampicin irrigation solution was the most effective in the decontamination of allografts previously contaminated with Staphylococcus aureus. Gentamicin, high-concentration fusidic acid, low-concentration fusidic and saline irrigation solutions may also be used respectively, according to their effectiveness.

Subtalar Distraction Arthrodesis Using Fresh-Frozen Allogeneic Femoral Head Augmented With Local Autograft

Tricortical autograft has been commonly used in subtalar distraction arthrodesis (SDA) for severe calcaneal malunion. Structural allograft enriched with orthobiological agents is an alternative. This study was performed to evaluate the results of SDA using fresh-frozen allogeneic femoral head without the addition of orthobiological agents. We retrospectively reviewed 15 consecutive SDA procedures (13 patients) with allogeneic femoral head augmented with local autograft for the treatment of severe calcaneal malunion. Clinical outcome was evaluated with the American Orthopaedic Foot & Ankle Society (AOFAS) ankle-hindfoot score, visual analog scale (VAS) pain score, Short Form-12 (SF-12), range of motion (ROM) of the ankle joint, and patient satisfaction rate. Radiographic assessment included the talar declination angle (TDA), calcaneal inclination angle (CIA), lateral talocalcaneal angle (LTCA), heel height, calcaneal length, and union time. At a median follow-up of 36.0 months (range, 24-47 months), all 15 feet (100%) achieved union, at a median of 13.0 weeks (range, 12-18 weeks). The AOFAS score and VAS pain score improved significantly, with a satisfaction rate of 93.3%. The TDA, CIA, LTCA, and heel height improved significantly. The median increase in heel height was 8.6 mm (range, 1.9-20.1 mm). There was a significant reduction in calcaneal length. Complications included 1 varus malalignment, 1 complex regional pain syndrome, 1 hardware irritation, and 1 sural neuralgia. This study found that SDA using fresh-frozen femoral head allograft without an orthobiological agent was cost-effective and may have outcomes comparable to those using autograft or allograft enriched with orthobiological agents.

Fate of large structural allograft for treatment of severe uncontained glenoid bone deficiency

Structural allografts have been used for management of large defects of the glenoid. We describe a surgical technique for graft preparation and the radiographic and clinical results of a series of patients using this technique. In 19 consecutive patients, a polymethyl methacrylate mold was used to shape a single graft from a fresh-frozen femoral head to press fit within the glenoid defect. We evaluated the clinical and radiographic results with a minimum 2-year follow-up or until revision to another total shoulder replacement. Six patients showed more than 50% resorption of the graft. Four of these six patients also had less than 50% graft incorporation, and these findings were associated with a less favorable clinical outcome. In 3 of 6 cases in which poly-L-lactic acid bioresorbable screws were used, a significant giant cell reaction was noted at the time of revision surgery. Seven of nine patients with metal screw fixation had bent, broken, or worn screws because of graft collapse and contact with the prosthetic humeral head. Four of the five revision cases that were converted to a reverse total shoulder replacement had sufficient bone incorporation and volume of bone to allow for secure glenoid and screw fixation. The surgical technique described is useful in creation of a well-fitting graft. The amount of bone resorption and bone incorporation and clinical outcome have wide variability. In those cases where revision was performed with another total shoulder replacement, there was sufficient bone incorporation and sufficient bone mass to allow component fixation.

Biomechanical effect of bone cement augmentation on rotational stability and pull-out strength of the Proximal Femur Nail Antirotation™

Introduction After surgical treatment of osteoporotic hip fractures, complications such as implant cut-out are reported to be high and implant failure often is associated with poor bone quality. As augmentation is reported to enhance implant anchorage, the aim of our study was to investigate the effect of bone cement augmentation on the rotational stability and the pull-out resistance of the Proximal Femur Nail Antirotation™ (PFNa) blade. Materials and methods A total of 18 fresh-frozen femoral heads (mean age 68 years, standard deviation (SD) 8.2) were scanned with quantitative computed tomography (qCT) for bone mineral density (BMD) measurements and instrumented with a PFNa blade. Nine specimens were augmented with a mean volume of 4.4 ml Traumacem V+. After cement consolidation, the blade was rotated for 60° for the rotational test. Subsequently, the blade was extracted from the specimens. Force, torque, displacement and angle were recorded constantly. Results In the rotational test, the mean maximum torque in the augmented group (17.2 Nm, SD 5.0) was significantly higher ( p = 0.017) than in the non-augmented group (11.7 Nm, SD 3.5). The pull-out test also yielded a significant difference ( p = 0.047) between the augmented (maximum pullout force: 2315.2 N, SD 1060.6) and the non-augmented group (1180.4 N, SD 1171.4). Discussion Augmentation of femoral heads yielded a significantly superior rotational stability, as well as an enhanced pull-out resistance, compared to the non-augmented state. However, the higher the BMD of the specimens, the lower was the effect of augmentation on the rotational stability. Therefore, augmentation can be a good clinical tool to enhance implant anchorage in osteoporotic bone.

The concentration of antibiotic in fresh-frozen bone graft

We investigated the antibiotic concentration in fresh-frozen femoral head allografts harvested from two groups of living donors. Ten samples were collected from patients with osteoarthritis of the hip and ten from those with a fracture of the neck of the femur scheduled for primary arthroplasty. Cefazolin (1 g) was administered as a pre-operative prophylactic antibiotic. After storage at -80 degrees C for two weeks the pattern of release of cefazolin from morsellised femoral heads was evaluated by an in vitro broth elution assay using high-performance liquid chromatography. The bioactivity of the bone was further determined with an agar disc diffusion and standardised tube dilution bioassay. The results indicated that the fresh-frozen femoral heads contained cefazolin. The morsellised bone released cefazolin for up to four days. The concentration of cefazolin was significantly higher in the heads from patients with osteoarthritis of the hip than in those with a fracture.Also, in bioassays the bone showed inhibitory effects against bacteria.We concluded that allografts of morsellised bone from the femoral head harvested from patients undergoing arthroplasty of the hip contained cefazolin, which had been administered pre-operatively and they exhibited inhibitory effects against bacteria in vitro.

Circumferential thoracolumbar corrective fusion with an anterior interbody fresh-frozen femoral head allograft for osteoporotic lower acute kyphosis: a case report

IntroductionLower acute kyphosis (LAK) is a postural deformity caused by severe osteoporotic vertebral collapse at the thoracolumbar junction. Corrective surgery is indicated for severe cases, but no case report using a fresh-frozen femoral head allograft was found in the English literature.Case presentationA 69-year-old Japanese woman with severe LAK with osteoporotic vertebral fractures from T11 to L2 complained of severe back pain and difficulty in walking. The rigid kyphosis measured 74° from T10 to L3. The patient underwent an anterior release and interbody fusion using a fresh-frozen femoral head allograft (T11-L3) and a posterior instrumented fusion (T10-L3). Postoperatively, kyphosis was corrected to 28°, and the patient's symptoms were alleviated. The allograft bone was fully incorporated 1 year postoperatively. A new vertebral fracture at T10 occurred after 2 years, resulting in a slight loss of correction. A kyphosis angle of 35° at 2 years was maintained at 12 years (age, 81 years). She remained free of back pain and able to walk without a cane over the 12-year follow-up.ConclusionFor treatment of severe osteoporotic LAK, anterior reconstruction is essential to obtain good spinal alignment and prevent recurrence. A fresh-frozen femoral head allograft, in combination with rigid posterior instrumented fixation, fulfills this function.

Strain imparted during impaction grafting may contribute to bony incorporation

In order to investigate the osteoinductive properties of allograft used in impaction grafting and the effect of strain during impaction on these properties, we designed an in vitro experiment to measure strain-related release of bone morphogenetic protein-7 (BMP-7) from fresh-frozen femoral head allograft. A total of 40 10 mm cubes of cancellous bone were cut from ten samples of fresh-frozen femoral head. The marrow was removed from the cubes and the baseline concentrations of BMP-7 were measured. Specimens from each femoral head were allocated to four groups and subjected to different compressive strains with a material testing machine, after which BMP-7 activity was reassessed. It was present in all groups. There was a linear increase of 102.1 pg/g (95% confidence interval 68.6 to 135.6) BMP-7 for each 10% increase in strain. At 80% strain the mean concentration of BMP-7 released (830.3 pg/g bone) was approximately four times that released at 20% strain. Activity of BMP-7 in fresh-frozen allograft has not previously been demonstrated. This study shows that the freezing and storage of femoral heads allows some maintenance of biological activity, and that impaction grafting provides a source of osteoinductive bone for remodelling. We have shown that BMP-7 is released from fresh-frozen femoral head cancellous bone in proportion to the strain applied to the bone. This suggests that the impaction process itself may contribute to the biological process of remodelling and bony incorporation.

Subtalar Distraction Arthrodesis Using Interpositional Frozen Structural Allograft

Subtalar bone-block distraction arthrodesis using structural autograft carries the risk of donor site morbidity. Recent reports suggest that structural allograft may be an attractive alternative to structural autograft in subtalar arthrodesis. This prospective study analyzes subtalar distraction arthrodesis using interpositional structural allograft. Between 2000 and 2006, 22 patients (24 feet; mean age, 45.6 years) underwent subtalar arthrodesis with interpositional fresh-frozen femoral head structural allograft. Indications included subtalar arthrosis, loss of heel height, and anterior ankle impingement. Clinical outcome was assessed using the AOFAS ankle-hindfoot scoring system. Time to union was determined by previously reported clinical findings and radiographic evidence for bridging trabeculation between host bone and structural allograft. Mean followup was 35.8 months for 20 patients (21 feet) available for followup evaluation. Union was achieved in 19 of 21 patients (90%) at a mean of 15.5 (range, 11 to 19) weeks. Mean AOFAS hindfoot score improved from 21 to 71 points (p < 0.05). Radiographic analysis suggested significant (p < 0.05) improvement in all measurements. Complications included nonunion (2), varus malalignment (1), persistent subfibular impingement (1), sural neuralgia (1), and prominent hardware (2). Both patients with nonunions had avascular bone at the arthrodesis site and used tobacco products. This study supports recent publications that subtalar arthrodesis using interpositional structural allograft can have a favorable outcome. Our clinical and radiographic results suggest that restoration of hindfoot function and dimensions with structural allograft are comparable to results reported for the same procedure using structural autograft. Level IV, prospective case series.