Sung Lee

Impact of operative time on early joint infection and deep vein thrombosis in primary total hip arthroplasty

PURPOSEnInfections and deep vein thrombosis (DVT) after total hip arthroplasty (THA) are challenging problems for both the patient and surgeon. Previous studies have identified numerous risk factors for infections and DVT after THA but have often been limited by sample size. We aimed to evaluate the effect of operative time on early postoperative infection as well as DVT rates following THA. We hypothesized that an increase in operative time would result in increased odds of acquiring an infection as well as a DVT.nnnMETHODSnWe conducted a retrospective analysis of prospectively collected data using the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) database from 2006 to 2015 for all patients undergoing primary THA. Associations between operative time and infection or DVT were evaluated with multivariable logistic regressions controlling for demographics and several known risks factors for infection. Three different types of infections were evaluated: (1) superficial surgical site infection (SSI), an infection involving the skin or subcutaneous tissue, (2) deep SSI, an infection involving the muscle or fascial layers beneath the subcutaneous tissue, and (3) organ/space infection, an infection involving any part of the anatomy manipulated during surgery other than the incisional components.nnnRESULTSnIn total, 103,044 patients who underwent THA were included in our study. Our results suggested a significant association between superficial SSIs and operative time. Specifically, the adjusted odds of suffering a superficial SSI increased by 6% (CI=1.04-1.08, p<0.0001) for every 10-minute increase of operative time. When using dichotomized operative time (<90minutes or >90minutes), the adjusted odds of suffering a superficial SSI was 56% higher for patients with prolonged operative time (CI=1.05-2.32, p=0.0277). The adjusted odds of suffering a deep SSI increased by 7% for every 10-minute increase in operative time (CI=1.01-1.14, p=0.0335). No significant associations were detected between organ/space infection, wound dehiscence, or DVT and operative time either as continuous or as dichotomized.nnnCONCLUSIONnProlonged operative times (>90min) are associated with increased rates of superficial SSIs, but not deep SSIs, organ/space infections, wound dehiscence, or DVT.nnnLEVEL OF EVIDENCEnIII.

Percutaneous Posterior to Anterior Screw Fixation of the Talar Neck: Soft Tissue Structures at Risk

Category: Trauma Introduction/Purpose: Fractures of the talar neck and body can be fixed with percutaneously placed screws directed from anterior to posterior or posterior to anterior. The latter has been found to be biomechanically and anatomically superior. Percutaneous pin and screw placement poses anatomic risks for posterolateral and posteromedial neurovascular and tendinous structures. The objective of this study was to enumerate the number of trials for proper placement of two parallel screws and to determine the injury rate to neurovascular and tendinous structures. Methods: Eleven fresh frozen cadaver limbs were used. 2.0 mm guide wires from the Stryker (Selzach, Switzerland) 5.0-mm headless cannulated set were percutaneously placed (under fluoroscopic guidance) into the distal posterolateral aspect of the ankle. All surgical procedures were performed by a fellowship-trained foot and ankle surgeon. Malpositioned pins were left intact to allow later assessment of soft tissue injury. The number of guide wires needed to achieve an acceptable positioning of the implant was noted. Acceptable positioning was defined as in line with the talar neck axis in both AP and lateral fluoroscopic views. After a layered dissection from the skin to the tibia, we evaluated neurovascular and tendinous injuries, and measured the shortest distance between the closest guide pin and the soft tissue structures, using a precision digital caliper. Results: The mean number of guide wires needed to achieve acceptable positioning for 2 parallel screws was 2.91 ± 0.70 (range, 2 - 5). The mean distances between the closest guide pin and the soft tissue structures of interest were: Achilles tendon, 0.53 ± 0.94 mm; flexor hallucis longus tendon, 6.62 ± 3.24 mm; peroneal tendons, 7.51 ± 2.92 mm; and posteromedial neurovascular bundle, 11.73 ± 3.48 mm. The sural bundle was injured in all the specimens, with 8/11 (72.7%) in direct contact with the guide pin and 3/11 (17.3%) having been transected. The peroneal tendons were transected in 1/11 (9%) of the specimens. The Achilles tendon was in contact with the guide pin in 6/11 (54.5%) specimens and transected in 2/11 (18.2%) specimens. Conclusion: The placement of posterior to anterior percutaneous screws for talar neck fixation is technically demanding and multiple guide pins are needed. Our cadaveric study showed that important tendinous and neurovascular structures are in close proximity with the guide pins and that the sural bundle was injured in 100% of the cases. We advise performing a formal small posterolateral approach for proper visualization and retraction of structures at risk. Regardless, adequate patient education about the high risk of injury from this procedure is crucial.

Incidence of Venous Thromboembolism in Orthopaedic Foot and Ankle Surgeries

Category: Other Introduction/Purpose: Venous thromboembolism (VTE) is a rare but potentially lethal complication following orthopaedic foot and ankle surgery. Surgeons continue to debate the types of patients and procedures in which it is appropriate to use chemical thromboprophylaxis. A recent meta-analysis concluded that patients at high risk for VTE after foot and ankle surgery should receive prophylaxis, but there remains a paucity of data to elucidate which demographic or comorbidity variables are most strongly associated with development of VTE. The incidence of VTE after orthopaedic foot and ankle surgery stratified by specific procedure has yet to be examined. The purpose of this study is to report the incidence of and identify risk factors for VTE in a large sample of patients receiving orthopaedic foot and ankle surgery. Methods: In this study, we retrospectively analyzed prospectively-collected data from the National Surgical Quality Improvement Program (NSQIP) 2006 to 2015 data files. The incidence of VTE was calculated for 30 specific orthopaedic foot and ankle surgeries and for four broad types of foot and ankle surgery. A total of 23,212 patients were identified and grouped by current procedures terminology (CPT) codes. Demographic, comorbidity, and complication variables were analyzed to determine associations with development of VTE. Pearson’s chi-squared test was used to compare categorical variables and Student t test was used to compare continuous variables. P-values of p<0.05 were considered statistically significant. Multivariable modelling was not possible due to the very low number of VTE cases relative to non-VTE cases. Results: The mean age at the time of surgery was 52.7±17.8 years. VTE events were documented 142 times in our sample, yielding an overall sample VTE incidence of 0.6%. The types of procedures with the highest frequency of VTE were ankle fractures (105/15,302 cases, 0.7%), foot pathologies (28/5,466, 0.6%), and arthroscopy (2/398, 0.5%). Female sex, increasing age, obesity level, inpatient status, and non-elective surgery were all significantly associated with VTE events. Postoperative pneumonia was significantly associated with VTE development. Patients who developed a VTE stayed at the hospital after surgery significantly longer than patients without VTE (6.2 vs. 3.1 days). Patients who developed VTE also had significantly higher estimated probability of morbidity (8.0% vs. 6.0%) and mortality (2.0% vs. 1.0%) when compared to patients without VTE. Conclusion: The present study confirms that VTE events after foot and ankle procedures are rare. The data presented suggest that female sex, increasing age, higher BMI, inpatient status, and non-elective procedures are associated with increased risk for VTE after orthopaedic foot and ankle surgery. Prospective, randomized, controlled trials are necessary to definitively determine the efficacy of chemoprophylaxis and to develop evidence-based clinical practice guidelines to minimize VTE after foot and ankle procedures.

Postoperative Tourniquet Pain in Patients Undergoing Foot and Ankle Surgery

Category: Other Introduction/Purpose: The tourniquet is commonly used in orthopedic surgeries on the upper and lower extremities to reduce blood loss, improve visualization, and expedite the surgical procedure. However, tourniquets have been associated with multiple local and systemic complications, including postoperative pain. Guidelines vary regarding ideal tourniquet pressure and duration, while the practice of fixed, high tourniquet pressures remains common. The relationship between tourniquet pressure, duration, and postoperative pain has been studied in various orthopaedic procedures, but these relationships remain unknown in foot and ankle surgery. The purpose of this study was to assess for correlation between excessive tourniquet pressure and duration and the increased incidence of tourniquet pain in foot and ankle surgery patients. Methods: Retrospective chart review was performed for 132 adult patients who underwent foot and ankle surgery with concomitant use of intraoperative tourniquet at a single institution between August and December of 2015. Patients with history of daily opioid use of 30 or more morphine oral equivalents for greater than 30 days, patients who underwent foot and ankle surgery without regional nerve block, patients deemed to have failed regional nerve block, and patients who underwent foot and ankle surgery without tourniquet use were excluded. Patient’s baseline systolic blood pressure, tourniquet pressure and duration, tourniquet deflation time, tourniquet reinflation pressure and duration, intraoperative blood pressure and heart rate changes, intra-operative opioid consumption, PACU pain scores, PACU opioid consumption, and PACU length of stay were collected. Statistical correlation between tourniquet pressure and duration and postoperative pain scores, pain location, narcotic use, and length of stay in PACU was assessed using linear regression in SPSS. Results: Average age of patients was 47.6 years (Range: 16 - 79). Tourniquet pressure was 280 mmHg in 90.6% of patients (Range: 250-300 mmHg). Only 3.8% percent of patients had tourniquet pressures 100-150 mmHg above systolic blood pressure. Mean tourniquet time was 106.2 ± 40.1 min. Tourniquet time showed significant positive correlation with morphine equivalents used in the perioperative period (N = 121; r = 0.406; p < 0.001). Long tourniquet times (= 90 minutes) were associated with greater intraoperative opioid use than short tourniquet times (= 90 minutes) (19 mg ± 22 mg vs. 5 mg ± 11.6 mg; p <0.001). Tourniquet duration and PACU length of stay had a positive association (R2 = 0.4). Conclusion: The majority of cases of foot and ankle surgery at our institution did not adhere to current tourniquet use guidelines, which recommend tourniquet pressure between 100 and 150 mmHg above patient’s systolic blood pressure. Prolonged tourniquet times at high pressures not based on limb occlusion pressure, as observed in our study, lead to increased pain and opioid use and prolonged time in PACU. Basing tourniquet pressures on limb occlusion pressures could likely improve the safety margin of tourniquets, however randomized studies need to be completed to confirm this.

Hemi vs. Total joint arthroplasty for hallux rigidus: a systematic review and a Meta-analysis

Category: Midfoot/Forefoot Introduction/Purpose: Advanced-stage arthritis of the first metatarsophalangeal joint (MTPJ), or “Hallux Rigidus” (HR) is a common forefoot pathology. When surgery is indicated, arthroplasty is an alternative to arthrodesis, which aims to preserve MTPJ dorsiflexion. Since it is unclear whether total-toe or hemi-toe devices are preferred implants in MTPJ arthroplasty, we completed a systematic review of the literature and did a meta analysis to test which type of implants clinically outperform in hallux rigidus. Methods: A systematic review of MTPJ arthroplasty was performed using Pubmed, EMBASE, SCOPUS, and Cochrane library for the years 2000 to 2017. Data was extracted from articles containing both preoperative and postoperative endpoints for either hemi or total MTPJ arthroplasty cases. To be eligible for inclusion, studies must have had a mean follow-up window of at least 24 months and standard deviation of outcome. Total eleven studies were included for review, seven studies with hemi replacement and six studies with total arthroplasty. Pooled mean values were calculated, and a forest plot was created comparing pre-and post-operative American Orthopedic Foot and Ankle Score (AOFAS), visual analogue scale (VAS), and range of motion (ROM) results for both hemi-toe and total-toe arthroplasty. Statistical analysis was performed using SPSS. Results: Mean postoperative AOFAS scores in patients undergoing hemiarthroplasty improved by 50.7 points (95%CI: 48.5, 52.8), which was higher than the mean postoperative AOFAS improvement of 40.6 points (95%CI: 38.5, 42.8) seen in total-toe patients. Mean postoperative VAS improvement in hemiarthroplasty was 6.05 points (95%CI: 5.92, 6.18), which was comparable to the mean VAS improvement of 6.29 points (95%CI: 6.02, 6.55) seen in total arthroplasty. Mean postoperative MTPJ ROM improved by 43.0 degrees (95%CI: 39.3, 46.6) in hemi-toe patients, which exceeded the mean ROM improvement of 32.5 degrees (95%CI: 29.9, 35.1) found in total-toe cases. A meta-analysis of the data revealed non-significant statistical trends for AOFAS and ROM in favor of hemiarthroplasty. Conclusion: Hemi-surface implants in MTPJ arthroplasty may improve postoperative AOFAS and ROM results to a greater extent than total-toe devices. High-quality randomized controlled studies are needed to confirm long-term surgical outcomes in these patients.

Ankle Fusion Percutaneous Home Run Screw Fixation: technical aspects and soft tissue structures at risk

Category: Ankle Arthritis Introduction/Purpose: During internal fixation of ankle fusions, besides the standard crossed screw fixation pattern, the use of a percutaneously placed augmenting screw, directed from the posterolateral tibial metaphysis proximally across the ankle into the talar neck (“ankle fusion home run screw”), is a widely used technique. The placement of this screw is technically demanding and multiple attempts under fluoroscopy guidance are frequently needed to achieve a perfect positioning of the implant. Injuries to local neurovascular and tendinous structures might happen. The objective of this cadaver study was to identify the number of attempts necessary for a perfect positioning of the ankle fusion home run screw and the neurovascular and tendinous structures at risk. Methods: Eleven fresh frozen cadaver limbs were used. Guide wires (3.2 mm) from the Stryker (Selzach, Switzerland) 7.0-mm headless cannulated set were percutaneously placed into the distal posterolateral aspect of the leg, under fluoroscopic guidance, with the ankle held in neutral position. Mal positioned pins were not removed and served as guidance for the following pins. The number of guide wires needed to achieve an acceptable positioning of the implant was noted. After a layered dissection from the skin to the tibia, we evaluated neurovascular and tendinous injuries, and measured the shortest distance between the closest guide pin and the soft tissue structures, using a precision digital caliper. Results: The mean number of guide wires needed to achieve and acceptable positioning of the implant was 2.09 (SD 0.83, range 1- 4). The mean distances between the closest guide pin and the soft tissue structures of interest were: Achilles tendon 6.90 mm (SD 3.74 mm); peroneal tendons 9.65 mm (SD 3.99 mm); sural neurovascular bundle 0.97 mm (SD 1.93 mm); posteromedial neurovascular bundle 14.26 mm (SD 4.56 mm). Sural bundle was in contact with the guide pin in 5/11 specimens (45.5%) and transected in 3/11 specimens (27.3%). Conclusion: The placement of percutaneous ankle fusion home run screws is technically demanding and multiple guide pins are needed. Our cadaveric study showed that important tendinous and neurovascular structures are in close proximity with the guide pins and that the sural bundle is injured in approximately 73% of the cases. Caution should be taken during percutaneous placing of screws and an appropriate approach and surgical dissection to bone is advised.

Vascular supply at risk during lateral release of the patella during total knee arthroplasty: A cadaveric study

IntroductionnLateral release to improve patellar tracking is commonly performed during total knee arthroplasty. Blood is supplied to the lateral patella by two main arteries: the superior and inferior lateral genicular arteries. The transverse infrapatellar artery also branches off the lateral inferior genicular artery to supply the inferior half of the patella. Severance of any of these arteries during lateral release can lead to avascular necrosis of the patella. This cadaveric study investigates the lateral vasculature to the patella and whether it can be visualized and preserved during lateral release of the patella.nnnMaterials and methodsnThis study involved ten cadavers, each of which underwent lateral release of the patella. One senior joint surgeon performed and supervised the incisions and attempted to locate and preserve these vessels. We then quantified the number of cadavers with visualized blood vessels and analysed their location and course to determine whether they could be preserved during lateral release of the patella.nnnResultsnIn our study, three of the ten cadavers had an artery that was visible within the incisional plane and preserved. Two were the inferior lateral genicular artery, and one was the superior lateral genicular artery. In the other seven cadavers, no vessels were visualized during the lateral dissection.nnnConclusionsnThese results demonstrate that it is difficult to visualize blood supply to the patella during lateral release. Every attempt should be made to preserve these blood vessels to avoid devascularization to patella in the setting of an already severed medial vascularity due to standard approach to knee replacement.

Calcaneal Osteotomies in the treatment of Hindfoot Deformities: Comparison between One Screw vs Two Screws fixation technique

Category: Hindfoot Introduction/Purpose: Calcaneal osteotomy is a common procedure for hindfoot deformities correction. Screw fixation is the most common technique used to stabilize these osteotomies. The clinical decision regarding the number of screws used is frequently based on the surgeon’s experience without sufficient data regarding outcomes and complications. The aim of this study was to compare the outcomes and complications of one versus two screws fixation technique of sliding calcaneal osteotomies. Methods: We reviewed 190 patients (112 female, 78 male) who underwent corrective calcaneal osteotomy for hind-foot angular deformity between 2010-2016. The average age was 48.4 years (18-83), and mean follow-up was 28 weeks (4-150). We divided patients into two groups, according to the number of screws used in the osteotomy fixation (one or two). 85 osteotomies were fixed by one screw and 105 by two screws. We compared both groups regarding incision type, positioning and type of the screws (headed or headless) and complications (non-union, infection, hardware related heel pain). Results: The average time for radiographic union was similar between the groups, around 5.6 weeks (4-10 weeks). Non-unions were not found. The overall Incidence of complications was not significant different in the one screw group compare two screw group (12.7% x 8%, p-value 0.465). Infection rate was similar in both groups (4.7% vs 3.5%, p-value 0.674). There was not significant difference of hardware related heel pain between two groups (15.2% vs 8.5%, p-value 0.149). Similarly, no difference in incidence of hardware related symptoms between patients who used headed screw when comparing with headless screws. Conclusion: Our study compared results in the use of one screw versus two screws fixation technique for sliding calcaneal osteotomies. We found similar time for union. Base of date there was no significant difference of complications, infection, and hardware related heel pain between patients who used one screw when comparing two screws fixation technique for corrective calcaneal osteotomy.

Effectiveness of Lateral Soft Tissue Release of the 1st Metatarsophalangeal Joint Through a Medial Transarticular Approach – A Cadaver Study

Category: Bunion Introduction/Purpose: First metatarsophalangeal joint lateral soft tissue release is frequently performed during corrective surgery for hallux valgus deformity. Surgical approaches include an open dorsal approach as well as a medial transarticular approach. The medial transarticular approach avoids the need for a second incision while also attenuating the risk of avascular necrosis of the first metatarsal head. However, this method is limited by the poor visualization of the lateral structures through the joint. The objective of this study was to evaluate the effectiveness of the medial transarticular approach for lateral soft tissue release in the 1st metatarsophalangeal joint. Methods: Ten below-the-knee fresh-frozen cadaveric specimens were used (6 females, 4 males). The mean age was 73.4 years. Two specimens had moderate hallux valgus deformity. None of the samples had considerable degenerative changes of the first metatarsophalangeal joint. Lateral soft tissue release was performed using a single 2.5 cm medial incision. Lateral soft tissue release targeted the lateral collateral ligament, lateral capsule, adductor hallucis muscle tendon and lateral metatarsosesamoid suspensory ligament. A single surgeon performed all procedures. An extended lateral dissection of the 1st intermetatarsal space was carried out to examine the accuracy of the technique. Successful release of each targeted structure (4 total) was recorded for each specimen. Thus, the percentage of successful release was computed for each specimen. Injuries to important non-targeted structures were also registered. Results: All four targeted structures were successfully released (100%) in seven of the ten cadavers. Three out of four structures were released (75%) in one cadaver, while two of the four and one of the four targeted structures were successfully released in the other two cadavers (50% and 25% success respectively). Lateral collateral ligament was successfully released in all cadavers. Lateral joint capsule, adductor hallucis muscle tendon, and lateral metatarsosesamoid suspensory ligament were released in 80% of the specimens. 1st metatarsal head chondral and unintended release of lateral head of the flexor hallucis brevis occurred respectively in 40% and 50% of the procedures. No injuries to the flexor hallucis longus tendon, neurovascular bundle, deep transverse metatarsal ligament or chondral damage to the proximal phalanx were recorded. Conclusion: Lateral soft tissue release of the first metatarsophalangeal joint can be successfully performed through a medial transarticular approach. Inadvertent release of the lateral head of the flexor hallux brevis and chondral damage of the 1st metatarsal head are complications to be considered.

Lateral Ankle Instability Surgical Treatment: A Comparison Between Primary Repair and Revision Surgery

Category: Ankle, Sports Introduction/Purpose: Lateral ankle instability is a common cause of disability in the active population. Although the majority of patients can be treated conservatively, surgical repair of the ligaments, with or without reinforcement, represents an excellent option for refractory cases. Failed primary surgical repair, recurrence of the ankle instability and need for revision surgery can rarely happen and is probably affected by multiple variables. That includes patient’s characteristics such as BMI and comorbidities and surgical aspects such as the use of suture anchors and soft-tissue reinforcement. The purpose of this study was to compare patient’s characteristics and complication rates of primary repair and revision procedures. Methods: We retrospectively reviewed 231 patients (160 Female, 71 Male) who underwent surgical treatment for lateral ankle instability between 2010-2016. Thirty-two were revision cases (14.2%), including 24 females and 8 males, and 199 were primary direct repairs (85.8%). The mean age at the time of the surgery was 39 (19-65)years, and average follow-up was 9 (2-55) months. The procedures were performed by four different surgeons. All cases were reviewed based on age, gender, BMI, procedure type and number of incisions, comorbidities, and complications. Data found was compared between the two groups (primary repair and revision surgery) by T-test. A p-value <0.05 was considered significant. Results: The Brostrom-Gould procedure was used in 69.5% of the primary repairs and 63.6% of the revision cases. The use of suture anchors was also similar in both groups (51%). Repair of the calcaneofibular ligament was performed in 68% of primary repairs and 81.8% of the revisions. We didn’t find significant differences regarding comorbidities between two groups: smoking (23.4% x 27.2%, p-value 0.371); diabetes (6.8% x 6%, p-value 0.951) and body mass index above 30 (28.5% x 24.2%, p-value 0.347). We found significant difference in the complication rate of the procedures, with a higher incidence in the revision group (48.4%) when compared to the primary repair group (24%). That included: sural neuritis (15.1% x 3.4%), superficial peroneal neuritis (12.1% x 4.5%), skin problems (9% x 7.4%). Conclusion: Our study of 231 patients that underwent surgical treatment for lateral ankle instability found significant higher incidence of complications in patients who had revision procedures when compared to primary repair. No differences regarding smoking status, diabetes and BMI were found.