Phalangeal Osteotomy…To Perform or Not to Perform

Category: Bunion Introduction/Purpose: As the hallux valgus deformity progresses, patients can get mild to moderate arthritis of the metatarsophalangeal (MTP) joint. The degenerative process of MTP arthritis results in reactive tissue formation and proliferation of osseous and cartilaginous structures. For some patients, the results in dorsal bone spurs and pain with great toe dorsiflexion of irritation from shoes. Reconstructive procedures provide a surgical option for patients to address pain and functional limitations, prior to subchondral bone cyst formation and loss of joint space. Patients who underwent cheilectomy alone have been shown to have a high failure rate and progress to advanced disease. A phalangeal dorsiflexion osteotomy has become increasingly more popular amongst foot and ankle surgeons with the hopes of decreasing failure rate and improving early outcomes. Methods: This study was a retrospective review of prospectively collected data from 385 patients treated for hallux rigidus at a large academic medical center between July 2015 and November 2016. All patients underwent either a cheilectomy or cheilectomy with phalangeal osteotomy of the MTP joint. Collected patient reported outcomes (PROs) included in this study were SF12 M, SF12P, FAAM, VAS and PASS scores. Mann-Whitney t-test was performed using GraphPad Prism version 7.0b for Mac to compare procedure groups. Exclusion criteria included poly-trauma, revision of same procedure, and lack of pre or post- operative. Results: Eighteen patients met criteria, 8 underwent cheilectomy and 10 had a cheilectomy with osteotomy procedure. The average age was 51.9 amongst the cohort, with a total of 13 female and 5 males. Patients who underwent cheilectomy with osteotomy procedure had better outcomes across all outcome measure scores. When comparing postoperative scores, cheilectomy with osteotomy patients showed significantly higher scores compared to cheilectomy alone patients: SF12-M (56 vs 36, respectively; p=0.0333), and SF12P (52 vs 30, respectively p=0.0095). VAS scores and FAAM scores showed no statistical difference between the two cohorts. Despite surgical intervention, 50% of patients who received cheilectomy alone reported more pain post-operatively compared to no reports of worsening pain in patients who received cheilectomy with osteotomy. Conclusion: Patients with moderate to severe hallux rigidus demonstrate improved functional outcomes with phalangeal osteotomy in conjunction with cheilectomy compared to cheilectomy alone. Further research with larger cohorts would be beneficial to confirm the reports of this study and expand upon aspects of care that contribute to patient satisfaction and performance

Treatment of End-Stage Hallux Rigidus and Impact of Arthrodesis versus Arthroplasty on Patient Reported Outcomes

Category: Bunion, Midfoot/Forefoot Introduction/Purpose: Hallux rigidus is a degenerative disease of the first metatarsophalangeal joint. Severe, end-stage hallux rigidus can become debilitating with surgical intervention becoming necessary once conservative measures and shoe modifications have failed. Joint salvage procedures include metatarsal phalangeal (MTP) arthrodesis and MTP arthroplasty. The purpose of this study was to assess for differences in patient reported outcomes in two cohorts who underwent fusion or joint reconstruction. Methods: This study was a retrospective review of prospectively collected data of 385 patients from an academic medical institution. Patients who underwent surgical intervention from July 2015 to November 2016 were identified based on CPT codes for MTP arthrodesis (28750) and arthroplasty (28293). We extracted outcome scores including SF12-M, SF12-P, FAAM, and VAS scores. Exclusion criteria included poly-trauma, revision procedures, and lack of pre and post-operative outcome scores. Mann- Whitney t-test was performed using GraphPad Prism version 7.0b for Mac to compare procedure groups, with significance define by a p-value of 0.05. Results: A total of eighteen patients met the inclusion criteria, with 6 who underwent arthroplasty and 12 arthrodesis. The average age was 63.7 amongst the cohort, with a total of 16 female and 2 males. Patients who underwent arthrodesis had better outcomes across all parameters. When comparing preoperative and postoperative scores, arthrodesis patients showed greater improvement of SF12-M (arthrodesis 9 vs arthroplasty -2, p=0.05), and SF12-P (9 vs -16, respectively p=0.05) scores. Arthroplasty patients were more likely to have a decrease in their SF-12 scores. VAS scores and FAAM scores showed no statistical difference between the two cohorts. Postoperative VAS scores were worse in 33% of arthroplasty patients despite surgical intervention, compared to 10% of arthrodesis patients. Conclusion: Our results suggests that both procedures provide a statistically significant difference in pain with several patients having a Global Rate of Change that is “very much better”. However, fusion of the metatarsophalangeal joint results in improved pain and functional outcomes for patients with severe hallux rigidus. These findings are consistent with current reports in the literature, which are mostly case series reports. Larger studies are needed to provide appropriate power and better support the findings of this study

Moderate and intensive mechanical loading differentially modulate the phenotype of tendon stem/progenitor cells in vivo

To examine the differential mechanobiological responses of specific resident tendon cells, we developed an in vivo model of whole-body irradiation followed by injection of either tendon stem/progenitor cells (TSCs) expressing green fluorescent protein (GFP-TSCs) or mature tenocytes expressing GFP (GFP-TNCs) into the patellar tendons of wild type C57 mice. Injected mice were subjected to short term (3 weeks) treadmill running, specifically moderate treadmill running (MTR) and intensive treadmill running (ITR). In MTR mice, both GFP-TSC and GFP-TNC injected tendons maintained normal cell morphology with elevated expression of tendon related markers collagen I and tenomodulin. In ITR mice injected with GFP-TNCs, cells also maintained an elongated shape similar to the shape found in normal/ untreated control mice, as well as elevated expression of tendon related markers. However, ITR mice injected with GFP-TSCs showed abnormal changes, such as cell morphology transitioning to a round shape, elevated chondrogenic differentiation, and increased gene expression of non-tenocyte related genes LPL, Runx-2, and SOX-9. Increased gene expression data was supported by immunostaining showing elevated expression of SOX-9, Runx-2, and PPARγ. This study provides evidence that while MTR maintains tendon homeostasis by promoting the differentiation of TSCs into TNCs, ITR causes the onset of tendinopathy development by inducing non-tenocyte differentiation of TSCs, which may eventually lead to the formation of non-tendinous tissues in tendon tissue after long term mechanical overloading conditions on the tendon

Moderate and intensive mechanical loading differentially modulate the phenotype of tendon stem/progenitor cells in vivo.

To examine the differential mechanobiological responses of specific resident tendon cells, we developed an in vivo model of whole-body irradiation followed by injection of either tendon stem/progenitor cells (TSCs) expressing green fluorescent protein (GFP-TSCs) or mature tenocytes expressing GFP (GFP-TNCs) into the patellar tendons of wild type C57 mice. Injected mice were subjected to short term (3 weeks) treadmill running, specifically moderate treadmill running (MTR) and intensive treadmill running (ITR). In MTR mice, both GFP-TSC and GFP-TNC injected tendons maintained normal cell morphology with elevated expression of tendon related markers collagen I and tenomodulin. In ITR mice injected with GFP-TNCs, cells also maintained an elongated shape similar to the shape found in normal/untreated control mice, as well as elevated expression of tendon related markers. However, ITR mice injected with GFP-TSCs showed abnormal changes, such as cell morphology transitioning to a round shape, elevated chondrogenic differentiation, and increased gene expression of non-tenocyte related genes LPL, Runx-2, and SOX-9. Increased gene expression data was supported by immunostaining showing elevated expression of SOX-9, Runx-2, and PPARγ. This study provides evidence that while MTR maintains tendon homeostasis by promoting the differentiation of TSCs into TNCs, ITR causes the onset of tendinopathy development by inducing non-tenocyte differentiation of TSCs, which may eventually lead to the formation of non-tendinous tissues in tendon tissue after long term mechanical overloading conditions on the tendon

Utilizing Cost and Quality Measures to Guide Fixation of MTP Arthritis

Category: Midfoot/Forefoot Introduction/Purpose: Severe hallux rigidus is the 2nd most common disorder of the 1st metatarsophalangeal (MTP) joint and is present on more than 44% of radiographs taken in those over 80 years of age. Arthrodesis has been the proposed method of fixation for 1st MTP pathology. However, joint preserving alternatives to fusion have also been proposed to maintain joint motion and due to the relatively high nonunion rate (5.4%). However, few reports have investigated if the risk of complications from a fusion impact daily activities and functional outcomes. As such, we investigated the cost and quality associated with treatment of severe MTP arthritis to determine the optimal surgical intervention. Methods: This was a retrospective review of 384 patients from a prospectively collected foot and ankle platform registry in a payor-provider healthcare system. Patients who underwent surgical intervention from July 2015 to November 2017 were identified by CPT codes for MPT arthrodesis (28750) and arthroplasty (28293) as well as key words “hallux” and “rigidus”. Patient reported outcome scores were extracted from the medical records including SF12-M, SF12-P, FAAM, and a binary PASS score. Exclusion criteria included poly-trauma, neurological impairment, and revision procedures. The Mann-Whitney test was performed using Minitab 18 to compare procedure groups for the small samples without a normal distribution, and chi squared analysis was used to analyze the PASS score. Significance was defined by a p-value of <0.05. Additionally, cost data was gathered across the institution based on the previously mentioned CPT codes at the same institution, although statistical analysis was limited by reporting of average numbers. Results: A total of 35 patients met inclusion criteria, with 26 arthrodesis and 9 arthroplasty patients. The arthrodesis group had an average age of 63.4 and the arthroplasty group had an average age of 60.1. The arthrodesis group had higher post op scores in measures including SF12-M, SF12-P, FAAM, and PASS. The arthrodesis group also had greater increase in postoperative SF12-P, and FAAM compared to pre-op scores, with the arthroplasty having higher increase in SF12-M. Of these, the differences in PASS score (p=0.02) and the change in SF12-P were significant (p=0.05). Analysis of cost identified 25 logs of MTP arthroplasty with an average cost of $6,538 per case and 79 logs of MTP arthrodesis with an average cost of$5,086. Conclusion: This study suggests that patients treated with arthrodesis for 1st MTP arthritis have improved outcomes with greater cost containment. Although the PASS and SF-12 scores showed significant differences, all of the results including pain scores revealed greater improvement with arthrodesis, with the exception of the SF12 mental. The small cohorts in this study are a limitation, but these, results are consistent with the current literature. However, with both higher outcome scores and lower cost, arthrodesis appears to have significant advantages compared to arthroplasty and further studies can help guide clinical decision making in this patient population

Fully Reduced HMGB1 Enhances Nonunion Fracture Healing in Diabetic Rat Model

Category: Basic Sciences/Biologics; Diabetes Introduction/Purpose: Diabetes mellitus is a chronic metabolic disease that leads to serious complications including bone health and wound healing. Bone fractures commonly occur in diabetic patients, and are difficultly to heal due to prolonged inflammation, which leads to a higher risk of non-union. Fully reduced high mobility group box1 (frHMGB1) can play an important role in skeletal regeneration; however, the activity can be inhibited by Metformin; which is commonly used for the treatment of diabetes. The effect of frHMGB1 and Metformin on the bone fracture healing is largely unknown. In this study, we tested the hypothesis that frHMGB1 enhances healing in a nonunion bone fracture and Metformin inhibits the healing using a diabetic rat model. Methods: Diabetic fracture rat model was created by injection of streptozotocin into total 32 Sprague Dawley rats and confirmed by blood glucose levels.An incision was performed, tibia bones were fractured, followed by the muscle and skin wound closure.The rats were divided into four groups with 8 rats per group(Fig 1): Group-1 had no additional treatment;Group-2 were injected Metformin (IP, 160 mg/kg) daily;Group-3 were injected frHMGB1 into wound area (250 µg/kg) weekly;Group-4 were injected Metformin (IP, 160 mg/kg) daily and frHMGB1 into wound area (250 µg/kg) weekly. The rats were monitored postoperatively and sacrificed on postoperative day-28 and day-90. The blood samples were collected for HMGB1 & IL-1β.Tibia samples were also collected and examined by gross inspection, micro-CT images and histological analysis. Data was analyzed by One-way ANOVA followed by Fisher’s Least significance difference test. A p-value less than 0.05 was considered to be significantly different between the groups. Results: Metformin with frHMGB1 significantly decreased HMGB1 levels and decreased the enhanced expression of IL-1β compared to frHMGB1 alone. Micro-CT images showed completely healed at day-90 post-surgery in frHMGB1 rats while Metformin inhibited frHMGB1 enhanced bone fracture healing as evidenced by the gap in the fractured bone area(Fig 2). Histology analysis indicated that frHMGB1 enhanced fractured bone healing as evidenced by high density of the cells was found in the bone fracture area (Fig. 3). Safranin O and fast green staining along with Masson’s Trichrome staining confirmed the frHMGB1 local injection promoted fractured bone healing (Fig. 4) as evidenced by high quality bone tissue formation with collagen type I (red staining) and collagen type III (blue staining) in the fractured bone wound area. Conclusion: Fully reduced HMGB1 treatment enhanced healing in a nonunion diabetic rat model. The fracture site had high density of cells, quality bone tissue, and enhanced production of collagen I and III. However, Metformin inhibited frHMGB1-induced healing enhancement. In diabetic rats, nonunion bone fracture was present with evidence of inflammation showing elevated levels of HMGB1 and IL-1β.FrHMGB1 treatment enhanced healing of nonunion bone fracture by promoting cell proliferation and migration, limited HMGB1 concentration, increased collagen production. Although Metformin injection slowed down the bone fracture healing by inhibiting frHMGB1activity, it also blocked HMGB1 release and reduced the inflammation caused by HMGB1

Determining the force required in arthroscopic evaluation to assess the stability of syndesmotic ankle injury: a cadaveric study

peer reviewedIntroduction: The diagnosis of isolated distal tibio bular syndesmotic ankle instability proves to be a challenge. Although diagnostic imaging has added value, it is limited in the detection of distal syndesmotic ankle instability. The gold standard remains intraoperative testing through arthroscopic probing while externally stressing the ankle in a sagittal direction. However, no validated arthroscopic guidelines have been established to distinguish a stable from an unstable syndesmotic ankle joint. This cadaveric study presents anatomical and biomechanical data that can help surgeons correctly identify isolated distal syndesmotic ankle instability. Objective The purpose of this study is to quantify the necessary forces applied during ankle arthroscopy to evaluate syndesmotic instability in freshly frozen cadaveric ankles. Methods: A total of 16 fresh frozen cadaveric (age 58–74 years) ankles were included in the study. A dynamometer was used to measure the force necessary for the shaver tip to be inserted into the distal tibio bular joint with the ankle in a neutral position. Measurements were performed rst with the syndesmosis intact, and again following progressive transection of the syndesmotic ligaments, along with distal fixation. Results: Signi cant differences were noted in the mean force required between the anterior inferior tibio bular ligament (AITFL)+interosseous ligament (IOL) and no ligament cut methods (p<0.001 between the AITFL+IOL and AITFL cut (p<0.001; 95% CI 44.80 to 50.70), and between the AITFL+IOL and AITFL+IOL+ PITFL cut (p<0.001). There were also significant differences in the necessary mean forces applied between the one-SB and two-SB methods (p<0.001), between the one-SB and one-screw methods (p=0.010), between the one-SB and two screw methods (p=0.01), between the two-SB and two-screw methods (p=0.003) and between the one-screw and two-screw methods (p<0.001). Signi cant differences were found between the AITFL+IOL cut and the one-SB (p<0.001), the two-SB (p<0.001), the one-screw (p<0.001) and the two-screw (p<0.001) methods. Conclusions: This cadaveric study provides biomechanical data that can assist the surgeon in the arthroscopic evaluation of syndesmotic injuries. The data from this study need to be clinically correlated to ultimately assist in improving the outcome of patients with syndesmotic ankle injuries. Our study offers to bridge the gap to the development of arthroscopic tools that can identify the need for surgical xation to the syndesmosis based on the laxity of speci c ankle ligaments that contribute to subtle instability

Patient Reported Outcomes in Athletes following ORIF of Jones Fracture

Category: Lesser Toes, Midfoot/Forefoot, Sports Introduction/Purpose: Treatment of fractures to the 5th metatarsal metaphyseal-diaphyseal junction, known as Jones’ fractures, can present challenges in the elite athlete significantly prolonging return to play. Non-operative treatments in elite athletes result in a high incidence of nonunion and secondary fracture. Primary screw fixation remains the standard of care for athletes. However, delayed union and nonunion are still very common despite surgical fixation due to the fracture occurring in a watershed area with decreased healing potential. Bone marrow aspirate concentrate (BMAC) is an autologous source of hematopoeitic and mesenchymal stem cells that has been used in the treatment of poor healing fractures. We hypothesize that open reduction internal fixation (ORIF) augmented with BMAC will improve patient-reported outcome measures following Jones’ fractures in athletes. Methods: This study was a retrospective review of elite athletes that underwent intramedullary screw fixation augmented with BMAC for Jones’ fractures at an academic medical institution. All patients were assessed preoperatively and postoperatively to determine their pain outcomes based on their visual analog score (VAS). Student’s t test was used in statistical comparison of the preoperative and postoperative outcome scores. P < 0.05 was considered significant. Results: A total of 16 elite athletes were treated with ORIF with BMAC for a Jones fracture with a mean age of 22.2 years (range 19–26). There were 9 males and 7 females included in the study. Type of athlete ranged across various sport activities, with all patients functioning at a collegiate and/or professional level of elite athletics. The mean visual analog score for pain decreased from 6.2 preoperatively (range 3-8) to 2.75 postoperatively (range 1-6 p = 0.06). All patients have returned to elite competitive sport activity with reports of minimal to no pain. Conclusion: Intramedullary screw fixation of Jones’ fractures with BMAC results in optimal surgical outcomes in the elite athlete. A higher powered and long-term study with validated patient-reported outcomes is needed to confirm our observations

A Novel Kartogenin-Releasing Polymer Scaffold Promotes Wounded Rat Achilles Tendon Enthesis Healing

Category: Hindfoot Introduction/Purpose: Entheses have a special fibrocartilage transition zone where tendons and ligaments attach to bone. Enthesis injury is very common, and the reattachment of tendon to bone is a great challenge because healing takes place between a soft tissue (tendon) and a hard tissue (bone). We have now developed a kartogene (KGN)-containing polymer scaffold (KGN-P) that can precisely deliver KGN to damaged enthesis area. The effects of the KGN-containing polymer on the healing of wounded TBJ were investigated in vitro and in vivo. Methods: The proliferation and chondrogenesis of rat Achilles tendon stem cells (TSCs) grown in four conditions were measured: normal medium (Control); normal medium with 100 nM KGN (KGN); lysine diisocyanate (LDI)-glycerol scaffold with normal medium (LDI-P); LDI-glycerol-KGN scaffold with normal medium (KGN-P).A wound (1 mm) was created on each hind leg Achilles enthesis of all 8 rats (3 months old). The wounds were then treated either with 10 ul saline (Wound); or 10 ul of 10 uM KGN (KGN); or LDI polymer scaffold (LDI-P); or KGN-containing polymer scaffold (KGN-P). The rats were sacrificed on day 15 and 30 post-surgery, and their Achilles entheses were collected for gross inspection and histochemical analysis. Results: KGN-containing polymers have sponge-like structures (Fig. 1A-D), and release KGN in a time- and temperature-dependent manner (Fig. 1E). KGN-P scaffold induced chondrogenesis of TSCs (Fig. 2D, 2H) without changing cell proliferation (Fig. 2I), and enhanced fibrocartilage-like tissue formation (Fig. 3E). KGN (Fig. 3C) and LDI-P (Fig. 3D) treated groups exhibited unhealed wound areas as in saline group (Fig. 3B). Finally, KGN-P and KGN treated rat TSCs underwent chondrogenesis by upregulating collagen II, aggrecan, and SOX-9 expression (Fig. 3F). Conclusion: Our results showed that KGN-containing polymer scaffold enhanced wounded enthesis healing by inducing TSC chondrogenesis and promoting the formation of the fibrocartilage in the wound site. The KGN-P may be used for regeneration of wounded entheses in clinical settings. Future research will focus on optimizing KGN concentration and releasing rate in the polymer scaffold during enthesis healing

The superior regenerative potential of muscle-derived stem cells for articular cartilage repair is attributed to high cell survival and chondrogenic potential

Three populations of muscle-derived cells (PP1, PP3, and PP6) were isolated from mouse skeletal muscle using modified preplate technique and retrovirally transduced with BMP4/GFP.  In vitro, the PP1 cells (fibroblasts) proliferated significantly slower than the PP3 (myoblasts) and PP6 cells (muscle-derived stem cells); the PP1 and PP6 cells showed a superior rate of survival compared with PP3 cells under oxidative stress; and the PP6 cells showed significantly superior chondrogenic capabilities than PP1 and PP3 cells. In vivo, the PP6 cells promoted superior cartilage regeneration compared with the other muscle-derived cell populations. The cartilage defects in the PP6 group had significantly higher histological scores than those of the other muscle-derived cell groups, and GFP detection revealed that the transplanted PP6 cells showed superior in vivo cell survival and chondrogenic capabilities compared with the PP1 and PP3 cells. PP6 cells (muscle-derived stem cells) are superior to other primary muscle-derived cells for use as a cellular vehicle for BMP4-based ex vivo gene therapy to heal full-thickness osteo-chondral defects. The superiority of the PP6/muscle-derived stem cells appears to be attributable to a combination of increased rate of in vivo survival and superior chondrogenic differentiation capacity