Outcomes of Acute Repair Versus Nonrepair of Zone I Flexor Digitorum Profundus Tendon Injuries.

PURPOSE: The aim of this study was to determine whether the clinical results of zone I flexor digitorum profundus (FDP) tendon injuries managed with acute surgical repair are comparable to the clinical results of those managed without repair (eg, primary FDP excision or observation). METHODS: Patients aged ≥18 years presenting to a level 1 trauma center between 2015 and 2020 with zone I FDP tendon injury were identified with retrospective chart review. We assessed the following data: age, sex, physical therapy visits, surgical intervention, surgical complications (including infection, repeat surgery after the primary intervention, and rupture of repair), and patient-reported outcomes measurement information system scores. RESULTS: Twenty-six patients met the inclusion criteria. Group 1 (N = 15 patients, 23 fingers) patients were treated with acute surgical repair. Group 2 (N = 11 patients, 11 fingers) patients were managed without surgical repair, including FDP excision (N = 7) or observation alone (N = 4). In group 1, the average distance from the distal palmar crease to fingertip at the final follow-up was 1.6 cm (range, 0-4 cm). Fourteen of the 15 patients participated in >3 therapy visits. The following complications occurred: 4 fingers with rerupture (2 patients), 4 fingers with surgical wound dehiscence (2 patients), 3 infections (2 patients), and 4 repeat surgeries for these complications. In group 2, the average distance from the distal palmar crease to fingertip at the final follow-up was 1.1 cm (range, 0.5-3 cm). There were no infections, episodes of wound dehiscence, or repeat surgeries. At the final follow-up, both groups showed clinically meaningful improvement on Patient Reported Outcomes Measurement Information System (PROMIS) upper extremity, pain interference, and physical function scores, with similar PROMIS domain scores between groups. CONCLUSIONS: Patients treated without FDP tendon repair had similar outcomes to, and fewer complications than, patients treated with acute tendon repair. Our data suggest that the notable commitment of health care costs, time, and adherence to protocols/restrictions after surgical repair may not confer functional benefit. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

Pregnancy and Parental Leave During Orthopaedic Surgery Residency.

Background: Gender diversity in the field of orthopedic surgery has lagged behind other surgical subspecialties. One potential barrier to the recruitment and retention of female orthopedic surgeons lies in controversies surrounding pregnancy and parental leave during residency training, for which no clear guidelines exist. Trainees and residency programs face the challenge of balancing clinical and surgical competency with the health and well being of the mother and her child. This article addresses the current policies, health considerations, perceptions of parental leave and future recommendations regarding pregnancy and parental leave for orthopedic residents. Level of Evidence: V.

Extramedullary Guide Alignment Is not Affected by Obesity in Primary Total Knee Arthroplasty.

Coronal alignment of the tibial implant correlates with survivorship of total knee arthroplasty (TKA), especially in obese patients. The purpose of this study was to determine if obesity affects coronal plane alignment of the tibial component when utilizing standard extramedullary tibial guide instrumentation during primary TKA. A retrospective review from June 2017 to February 2018 identified 142 patients (162 primary TKAs). There were 88 patients (100 knees) with body mass index (BMI) < 35 kg/m2 and 54 patients (62 knees) with BMI ≥ 35.0 kg/m2. The cohorts did not differ in age (p = 0.37), gender (p = 0.61), or Charlson's comorbidity index (p = 0.54). Four independent reviewers measured the angle between the base of the tibial component and the mechanical axis of the tibia on the anteroposterior view of long-leg film at first postoperative clinic visit. Outliers were defined as patients with greater than 5 degrees of varus or valgus alignment (n = 0). Reoperations and complications were recorded to 90 days postoperatively. There was no significant difference in mean tibial coronal alignment between the two groups (control alignment 90.8 ± 1.2 degree versus obese alignment 90.8 ± 1.2 degree, p = 0.91). There was no difference in varus versus valgus alignment (p = 0.19). There was no difference in the number of outliers (two in each group, p = 0.73). There was no difference in rate of reoperation (p = 1.0) or complication (p = 0.51). Obesity did not affect coronal plane alignment of the tibial component when using an extramedullary guide during primary TKA in our population.

Unstable Lumbar Spine Osteomyelitis Caused by Trans-Foraminal Migration of Laparoscopic Adjustable Gastric Band Connection Tubing: A Case Report.

Background: Disconnection of the tubing between the port and LAGB is a well-known complication in general surgery and accounts for up to 17% of LAGB complications. Typically, when this complication occurs patients present with abdominal or pelvic complaints. A complication of spinal infection due to trans-foraminal migration has not been previously reported. The aim of this study is to highlight an unusual infection of the thoracolumbar spine due to laparoscopic adjustable gastric band (LAGB) intragastric erosion, and migration into the lumbar spine causing epidural abscesses, discitis, and osteomyelitis. This case underscores the importance of a thorough surgical history, complete imaging, and multi-disciplinary approach in management of complex spine infections. Methods: We report a case of LAGB tubing migration into the spinal canal through the left L2/L3 neural foramen resulting in symptomatic epidural abscesses and osteomyelitis. Results: Although dislodgement and migration of LAGB tubing has been reported previously, this is the first report of trans-foraminal migration and erosion of lumbar vertebrae, causing osteomyelitis of the spine and epidural abscess formation, subsequent instability and neurologic deficit requiring urgent operative intervention. Conclusions: Dislodgement and migration of LAGB tubing is a known complication. While it most commonly leads to abdominal and pelvic sequelae, in rare circumstances it may acutely affect the spine. Careful history, imaging, and multidisciplinary approach are paramount for the successful management.Level of Evidence: V.

Masks for the Reduction of Methyl Methacrylate Vapor Inhalation.

Background: Exposure to methyl methacrylate vapor (MMA) presents an occupational risk to orthopedic surgeons and ancillary personnel in the operating room. The purpose of this study was to identify a disposable face mask to reduce MMA organic vapor inhalation in the operative suite. Methods: First, the effectiveness of MMA vapor filtration was determined in the laboratory. A section of activated carbon impregnated filter face mask (Model 8514, 3M Inc.) was exposed to 150 ppm MMA vapor and MMA ppm of filtered air was monitored until MMA vapor was detectable. The face mask was then worn as directed in the operating room during routine cement mixing during total knee arthroplasty to determine the exposure to MMA vapors during the procedure both with and without the activated carbon impregnated filter face mask. Results: The activated carbon impregnated face mask was effective in reducing MMA vapor inhalation to non-detectable levels for up to 40 minutes in the laboratory at steady-state exposure of 150 ppm MMA vapor as well as throughout cement mixing and curing in the operative suite during routine total knee arthroplasty. Conclusions: An activated carbon impregnated face mask offers a solution for the orthopedic surgeon and supporting personnel who wish to limit their exposure to MMA vapors due to health concerns.Level of Evidence: III.

Weight-Bearing CT Scan After Tibial Pilon Fracture Demonstrates Significant Early Joint-Space Narrowing.

BACKGROUND: Posttraumatic osteoarthritis (PTOA) is a common and early sequela of tibial pilon fractures resulting in substantial long-term disability. New approaches are needed to objectively and reliably quantify early disease progression in order to critically assess the impact of interventions aimed at preventing or mitigating PTOA. Weight-bearing computed tomography (WBCT) scans provide a means for measuring joint space while the ankle is in a loaded, functional position. We assessed the interrater and intrarater reliability of a standardized, regional method to quantify joint-space loss following tibial pilon fracture compared with the uninjured contralateral ankle. METHODS: We prospectively enrolled 20 patients with intra-articular tibial pilon fractures that were surgically treated at 1 of 2 level-I trauma centers. Six months after injury, bilateral ankle WBCT scans were obtained. Joint space was measured by 4 reviewers at 9 discrete regions of the tibiotalar articulation on sagittal images. Measurements were repeated by reviewers 2 weeks later. To characterize the measurement method, interrater correlation coefficient estimates and test-retest reproducibility were calculated. RESULTS: The mean tibiotalar joint space was 21% less in the injured ankles compared with the contralateral uninjured ankles (p < 0.0001). The middle-lateral and middle-central regions of the joint demonstrated the greatest decrease in joint space between injured and uninured ankles. The interrater correlation coefficient of the measurement technique was 0.88, and the test-retest reproducibility was 0.80, indicating good reliability and reproducibility of the method. CONCLUSIONS: We developed a simple, standardized, and reliable technique to quantify tibiotalar joint space following tibial pilon fracture on WBCT. Significant loss of joint space is seen 6 months after the injury. This tool can be used to longitudinally quantify loss of joint space following pilon fracture and assess the impact of interventions to reduce PTOA.

Iatrogenic Articular Cartilage Injury in Arthroscopic Hip and Knee Videos and the Potential for Cartilage Cell Death When Simulated in a Bovine Model.

PURPOSE: To determine the incidence and characterize the severity of iatrogenic cartilage injuries. METHODS: Technique videos of arthroscopic femoral acetabular impingement procedures and meniscus repairs on VuMedi (n = 85) and Arthroscopy Techniques (n = 45) were reviewed and iatrogenic cartilage injuries were identified and graded (minor, intermediate, and major injury) by 2 independent reviewers. To demonstrate that even minor injuries on a cellular scale result in damage, a bovine osteochondral explant was used to create comparable minor iatrogenic injuries at varied forces that do not disrupt the articular surface (1.5 N, 2.5 N, and 9.8 N). Dead chondrocytes at the site of injury were stained with ethidium homodimer-2 and imaged with an Olympus FV1000 confocal microscope. χ2 tests were used for analysis; all results with P < .05 were considered significant. RESULTS: In total, 130 videos of arthroscopic meniscus and femoral acetabular impingement procedures were analyzed and the incidence of iatrogenic cartilage injury was 73.8%. There were 110 (70.0%) minor, 35 (22.3%) intermediate, and 11 (7.0%) major iatrogenic injuries. All forces tested in the minor injury bovine model resulted in chondrocyte death at the site of contact. CONCLUSIONS: Iatrogenic articular cartilage injuries are common in arthroscopy, occurring in more than 70% of the surgeon-published instructional videos analyzed. At least some chondrocyte death occurs with minor simulated iatrogenic injuries (1.5 N). CLINICAL RELEVANCE: The high rate of cartilage damage during arthroscopic technique videos likely under-represents the true incidence in clinical practice. Cell death occurs in the bovine minor injury model with minimal contact forces. This suggests iatrogenic cartilage damage during arthroscopy could contribute to clinical outcomes.

Scoliosis Curvature Follows Thoracic Organ Orientation.

STUDY DESIGN: Retrospective cohort study, Level of Evidence III. OBJECTIVE: To determine the relationship between internal organ orientation and adolescent idiopathic scoliosis (AIS) convexity directionality. SUMMARY OF BACKGROUND DATA: AIS affects 2% to 3% of the general population and demonstrations 80% to 99% right thoracic curve convexity. The mechanism of AIS as well as explanation for right-sided predominance is largely unknown. METHODS: A retrospective chart review of all patients with dextrocardia from 2008 to 2018 was performed at a single institution. Upright chest x-rays and scoliosis x-rays were evaluated for scoliosis by measurement of Cobb angle. Chart review was performed to extract age, advanced imaging results, and surgical intervention. RESULTS: Of 110 patients identified with dextrocardia, 19 patients exhibited radiographic features consistent with AIS (Cobb angle >10°). Fifteen (79%) of these patients demonstrated left-sided thoracic curvature. Six patients showed isolated dextrocardia with normal abdominal organ orientation; five patients (83%) showed left-sided thoracic curvature. There was not a statistical difference with regards to sex or curve severity. Magnetic resonance imaging (MRI) was performed on five patients with left-sided curvature without evidence of intra-spinal pathology. CONCLUSION: Dextrocardia shows increased incidence of AIS in both male and female patients. Left-sided thoracic curvature in cases with concurrent dextrocardia may not be associated with intra-spinal pathology as seen in the general population. These data suggest that thoracic organ orientation affects AIS convexity directionality. LEVEL OF EVIDENCE: 3.

Escherichia hermannii as the sole cause of osteomyelitis in a patient with an open tibial shaft fracture.

Escherichia hermannii is a rare monomicrobial cause of infection in humans. E. hermannii has never before been reported as the sole isolate from an infected open tibia fracture. We present a case of E. hermannii infection after a type III open tibia fracture. The patient was initially treated with irrigation and debridement, open reduction internal fixation and primary wound closure. However, after 8 weeks, he developed a draining wound and infection at the fracture site. He required a repeat debridement, hardware removal, external fixation and 6 weeks of intravenous ceftriaxone for treatment. At 2-year follow-up, he remains infection free, asymptomatic and continues to work with excellent functional outcomes. This case adds to the growing literature that evidences E. hermannii as an organism that can be pathogenic, virulent and cause monomicrobial infection.

Rare Post Traumatic Kyphoscoliosis of the Thoracolumbar Spine After Posterior Fusion for Adolescent Idiopathic Scoliosis: A Case Report and Review of the Literature.

Background: Vertebral fracture after posterior arthrodesis and instrumentation for idiopathic scoliosis is a rare occurrence with limited reported cases in the literature. Case Presentation: A 16-year-old female patient surgically treated for adolescent idiopathic scoliosis with T2-L1 posterior spinal fusion was in a low-energy fall resulting in fracture of L1 and new kyphosis and scoliosis of the thoracolumbar spine at the distal aspect of the fusion. The fracture was initially managed conservatively, however pain persisted and thus she was indicated for extension of the fusion and correction of the post-traumatic kyphosis. Conclusions: Fractures after posterior spinal fusion for idiopathic scoliosis are rare and evidence for the appropriate management remains limited in the literature.Level of Evidence: V.

Evidence of Selection Bias and Non-Response Bias in Patient Satisfaction Surveys.

Background: Patient satisfaction surveys are increasingly utilized to measure the patient experience and as a tool to assess the quality of care delivered by medical providers. Press Ganey (PG) is the largest provider of tools for patient satisfaction measurement and analysis. The purpose of this study was to determine if patient satisfaction surveys were subject to selection and/ or nonresponse bias. Methods: Patients seen in an outpatient academic orthopedic clinic were included in this retrospective cohort study. Demographic data included age, race, gender, marital status, primary payer, and native language. All surveys were administered by PG Associates per internal protocols adhering to exclusion criteria within the institutional contract with PG Associates. Results: 3.5% of outpatient encounters generated PG survey data, which were generated by 9.1% of all patients evaluated. The population of patients who were administered as well as patients who responded to the patient satisfaction survey represented a unique population with regards to age, race, gender, marital status, insurance status, and native language. Conclusions: Demographically, patients who were administered and patients who responded to PG surveys differed from the overall population of patients seen in an outpatient orthopedic setting, evidencing both selection and non-response bias. Because of these differences, and considering the small number of survey returned, caution should be exercised when interpreting and applying these data.Level of Evidence: III.

The Effect of Workers' Compensation Status on the Patient Experience.

BACKGROUND: Rating the patient experience is an increasingly important component of value-based health care. Generation of lower ratings on validated functional assessments by patients with Workers' Compensation is well known; however, the relationship between Workers' Compensation status and patient satisfaction is poorly described in orthopaedic patient populations. METHODS: All orthopaedic outpatient patient satisfaction surveys (Press Ganey) generated over an 18-month period at a U.S. academic tertiary care center were included in this study. Data with regard to the primary payer, demographic characteristics, orthopaedic subspecialty, and planned surgical interventions with the provider for whom the survey was completed were analyzed in conjunction with patient satisfaction data. RESULTS: During the study period, 3,720 consecutive patient satisfaction surveys were generated, and 244 surveys were generated by 215 patients with Workers' Compensation. Satisfied patients with Workers' Compensation were more likely to be male (p = 0.0007), to have higher mental health self-assessments (p = 0.004), and to be scheduled for surgical intervention (p = 0.03). Scheduling a surgical procedure was independently associated with improved patient satisfaction, whereas Workers' Compensation status was independently associated with dissatisfaction when adjusting for sex, language, race, and marital status. Across all patient satisfaction domains, patients with Workers' Compensation gave significantly lower scores (p < 0.05) compared with all other patients. Patients with Workers' Compensation were more likely to rate their overall health as lower compared with other patients (p < 0.0001). Patients with Workers' Compensation were more likely to give lower ratings to providers on a 1-to-10 scale (p < 0.0001) and were less likely to recommend the practice to others (p < 0.0001). CONCLUSIONS: Workers' Compensation status is a non-modifiable independent predictor of dissatisfaction with health care compared with other primary payer groups. Further research is warranted to understand the factors influencing patient satisfaction ratings.

Perioperative nutrition assessment in musculoskeletal trauma patients: Dietitian evaluation is superior to serum chemistries or modified screening questionnaire for risk stratification.

INTRODUCTION: Malnutrition is a potentially modifiable risk factor associated with increased hospital charges, major wound complication, and fracture non-union after orthopaedic surgery. The goal of this study was to examine the relationship between three nutrition screening tools and postoperative complications in patients undergoing acute fracture fixation. METHODS: Patients aged 18 or older undergoing acute operative fracture fixation at a Level I academic trauma center were screened upon admission using a malnutrition screening questionnaire (MSQ), and classified as low-, moderate- or high risk. Patients at moderate-to-high risk were assessed for clinical malnutrition by dietitian. Serum albumin, transferrin, total lymphocyte count, and 25(OH) Vitamin D were measured preoperatively. Primary outcome measures included twelve-month postoperative surgical and medical complications obtained by retrospective chart review. RESULTS: Of 373 patients, 17% were moderate-to-high risk of malnutrition by MSQ. Clinical malnutrition was diagnosed by dietitian in 4.3% of patients assessed. Nearly half of all subjects had deficiency in one or more serum biomarkers. Cost of biomarker assays was $624 per patient. Medical or surgical complications occurred in 19% of patients. Dietitian diagnosed malnutrition (clinical malnutrition) was the strongest predictor of complication (OR 3.49, p = 0.017). Hypoalbuminemia was also associated with increased complication risk (OR 1.79, p = 0.045). MSQ score was not correlated with postoperative complication. CONCLUSIONS: Among the examined malnutrition screening tools, clinical malnutrition had the strongest association with postoperative complication. Hypoalbuminemia was associated with increased odds of complication, however there was a large false positive rate with all tested serum chemistries and high associated hospital charges compared to dietitian assessment. MSQ was a poor predictor of malnutrition and clinical outcome. Dietetic assessment is advised for orthopaedic trauma patients.

Nonunion Rates Among Ulnar-Shortening Osteotomy for Ulnar Impaction Syndrome: A Systematic Review.

PURPOSE: The purpose of this study was to systematically review all available literature reporting nonunion rates of ulnar-shortening osteotomies (USO) used for the treatment of ulnar impaction syndrome (UIS) and to compare those rates among transverse versus oblique cuts for the osteotomy. METHODS: Electronic databases including PubMed, EMBASE, and Cochrane Central Register of Controlled Trials were searched for studies that evaluated outcomes of both transverse and oblique USO for UIS. Level of evidence was determined by 2 independent reviewers. Studies were screened based on Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and inclusion and exclusion criteria were applied. A total of 37 studies (1,423 patients) were included in final analysis. The average rate of nonunion and delayed union for each group (transverse and oblique osteotomy) was calculated. RESULTS: The average rate of nonunion among all osteotomies was 4.0%. The average rate of nonunion was 4.16% and 3.86% in transverse osteotomies and oblique osteotomies, respectively. This difference was not statistically significant. The average rate of delayed union, in those studies that reported delayed union, was 5.7%. The average rate of delayed union was 7.41% and 4.1% in transverse osteotomies and oblique osteotomies, respectively. CONCLUSIONS: Based on our review of the literature, there is no difference in the rate of nonunion between transverse and oblique osteotomies. Therefore, the decision of which of the 2 surgical techniques should not be based on rate of nonunion. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

Surgical modifications of the Kasai hepatoportoenterostomy minimize invasiveness without compromising short- and medium-term outcomes.

BACKGROUND: Biliary atresia (BA) causes progressive fibrosis and obliteration of the biliary tree, resulting in bile stasis and eventual liver dysfunction. It affects 1 in 10,000-18,000 infants, and if left untreated, universally leads to liver failure. The Kasai hepatoportoenterostomy (KPE) was developed as an effective surgical therapy for BA and can restore bile drainage into the intestine. Traditionally, the KPE procedure extra-corporealizes the liver to expose the portal plate. Here, we describe modifications to the procedure via a smaller incision in which the liver remains within the abdominal cavity and we compare the outcomes of this technique to previous institutional outcomes and to contemporary international series. MATERIALS AND METHODS: We identified all patients who underwent KPE for BA at a single institution between 1994 and 2012. Patient outcomes after the modified KPE performed from 2004 to 2012 were compared to data from infants who underwent the traditional KPE from 1994 to 2003. RESULTS: Ninety-nine patients were identified. Fifty-two were in the traditional KPE group and 47 in the modified KPE group. There was no difference in mean age at surgery. Median follow-up was 64 months (traditional KPE) and 46 months (modified KPE). The rate of native liver survival (39.1% vs 48.5%), overall survival (89.2% vs 97.8%), liver transplant occurring under one year of age (36.5% vs 40.4%) and median time to liver transplant (188 vs 172 days) were not statistically different between groups (p > 0.05 for all comparisons). The results of the modified KPE compared favorably to published outcomes. CONCLUSION: The described modifications to the KPE appear to yield equivalent outcomes when compared to the traditional KPE procedure and compare well with published outcomes in the literature. It is possible that the procedure described here results in less scarring and technically easier liver transplant procedures. LEVEL OF EVIDENCE: Level III.

A case of Histoplasma capsulatum variety capsulatum septic arthritis successfully treated with surgery, systemic antifungals, and local amphotericin cement beads.

Histoplasma capsulatum variety capsulatum (H. capsulatum) is a thermally dimorphic fungus that is endemic to the Mississippi River and Ohio River valley regions. Of the hundreds of thousands of patients exposed to this fungus, less than 1% develop a severe illness most commonly manifesting as pulmonary disease. Septic arthritis from hematogenous seeding with H. capsulatum or from direct inoculation has been reported only rarely in the literature. The first case of septic arthritis of the shoulder due to H. capsulatum occurring in an immunocompromised patient, treated successfully with irrigation and debridement, systemic antifungals, and local delivery of amphotericin B with cement beads, is reported here. Importantly, the addition of local amphotericin B delivery by cement beads to conventional treatment likely led to clinical cure in this patient.

Systematic Review of Tendon Transfer Versus Nerve Transfer for the Restoration of Wrist Extension in Isolated Traumatic Radial Nerve Palsy.

PURPOSE: To compare the outcomes of tendon transfer and nerve transfer for radial nerve palsy. METHODS: We performed a systematic review of the literature in EMBASE, PubMed, and Cochrane Database to include studies that address persistent traumatic radial nerve palsy treated with tendon transfer or nerve transfer surgery. RESULTS: We identified 2,044 citations; 1,512 texts were excluded because of content, and 96 texts were screened for eligibility. Texts were excluded if they did not report the motor score (M0 to M5 as determined by the British Medical Research Council) or measurements of range of motion of the wrist. Sixteen texts were eligible for qualitative synthesis. Outcomes of these studies show heterogeneity with regard to the technique and functional restoration. CONCLUSIONS: On the basis of the results of this systematic review, there does not seem to be a clearly superior technique; rather, there are advantages and disadvantages to each. Patient selection and surgeon experience are important when considering surgical interventions in this challenging clinical scenario. Nerve transfer surgery is an emerging technique that may offer patients meaningful functional gains with reduced donor site morbidity. LEVEL OF EVIDENCE: Level III.

Leland G. Hawkins, MD-His Life and Orthopaedic Legacy: Talus Fractures and the Hawkins Classification.

The long history of excellence and continued success of the University of Iowa Department of Orthopedics and Rehabilitation is due to the dedication and talent of generations of faculty, residents and staff. Many former Iowa Orthopedic residents have made significant contributions and become leaders in Orthopedic surgery. An orthopedic surgeon and scholar with roots at the University of Iowa deserving of tribute is Dr. Leland Greene Hawkins. His seminal investigation and interest in fractures of the talus established the well-known Hawkins Classification for talar neck fractures, which revolutionized treatment and quantified the risk of progression to avascular necrosis, earning him attention and respect worldwide.

Targeting mitochondrial responses to intra-articular fracture to prevent posttraumatic osteoarthritis.

We tested whether inhibiting mechanically responsive articular chondrocyte mitochondria after severe traumatic injury and preventing oxidative damage represent a viable paradigm for posttraumatic osteoarthritis (PTOA) prevention. We used a porcine hock intra-articular fracture (IAF) model well suited to human-like surgical techniques and with excellent anatomic similarities to human ankles. After IAF, amobarbital or N-acetylcysteine (NAC) was injected to inhibit chondrocyte electron transport or downstream oxidative stress, respectively. Effects were confirmed via spectrophotometric enzyme assays or glutathione/glutathione disulfide assays and immunohistochemical measures of oxidative stress. Amobarbital or NAC delivered after IAF provided substantial protection against PTOA at 6 months, including maintenance of proteoglycan content, decreased histological disease scores, and normalized chondrocyte metabolic function. These data support the therapeutic potential of targeting chondrocyte metabolism after injury and suggest a strong role for mitochondria in mediating PTOA.