Patient Adherence Following Knee Surgery: Evidence-Based Practices to Equip Patients for Success.

Patient adherence with postoperative wound care, activity restrictions, rehabilitation, medication, and follow-up protocols is paramount to achieving optimal outcomes following knee surgery. However, the ability to adhere to prescribed postoperative protocols is dependent on multiple factors both in and out of the patient's control. The goals of this review article are (1) to outline key factors contributing to patient nonadherence with treatment protocols following knee surgery and (2) to synthesize current management strategies and tools for optimizing patient adherence in order to facilitate efficient and effective implementation by orthopaedic health care teams. Patient adherence is commonly impacted by both modifiable and nonmodifiable factors, including health literacy, social determinants of health, patient fear/stigma associated with nonadherence, surgical indication (elective vs. traumatic), and distrust of physicians or the health care system. In addition, health care team factors, such as poor communication strategies or failure to follow internal protocols, and health system factors, such as prior authorization delays, staffing shortages, or complex record management systems, impact patient's ability to be adherent. Because the majority of factors found to impact patient adherence are nonmodifiable, it is paramount that health care teams adjust to better equip patients for success. For health care teams to successfully optimize patient adherence, focus should be paid to education strategies, individualized protocols that consider patient enablers and barriers to adherence, and consistent communication methodologies for both team and patient-facing communication.

Effects of Patient Assessment and Education by an Integrated Care Team on Postoperative Adherence and Failure Rates After Osteochondral Allograft and Meniscal Allograft Transplantation in the Knee.

Background: Patient nonadherence with prescribed rehabilitation protocols is associated with up to 16 times higher likelihood of treatment failure after osteochondral allograft transplantation (OCA) and meniscal allograft transplantation. Hypothesis: Patients who completed counseling with an orthopaedic health behavior psychologist as part of an evidence-based shift in practice at our institution would have significantly lower rates of nonadherence and surgical treatment failure versus patients who did not participate in counseling. Study Design: Cohort study; Level of evidence, 2. Methods: Patients in a prospective registry who underwent OCA and/or meniscal allograft transplantation between January 2016 and April 2021 were included for analysis when 1-year follow-up data were available. Of 292 potential patients, 213 were eligible for inclusion. Patients were categorized based on whether they participated in the preoperative counseling and postoperative patient management program: no health psych group (n = 172) versus health psych group (n = 41). Nonadherence was defined as documented evidence of a deviation from the prescribed postoperative rehabilitation protocol. Results: In this cohort of patients, 50 (23.5%) were documented to be nonadherent. Patients in the no health psych cohort were significantly more likely to be nonadherent (P = .023; odds ratio [OR], 3.4). Tobacco use (OR, 7.9), higher preoperative Patient-Reported Outcomes Measurement Information System (PROMIS) Pain Interference score, lower preoperative PROMIS Mental Health score, older age, and higher body mass index were also significantly associated with nonadherence (P < .001 for all). Patients who were nonadherent with the prescribed postoperative rehabilitation protocol during the first year after transplantation were 3 times more likely (P = .004) to experience surgical treatment failure than those who were adherent. Overall, 26.2% of patients in the no health psych group experienced surgical treatment failure versus 12.2% in the health psych cohort. Conclusion: Data from the present study suggest that preoperative counseling with a health behavior psychologist is associated with an improved rate of patient adherence and a lower proportion of surgical treatment failure after OCA and meniscal allograft transplantation. Patients who remained adherent to the postoperative protocol were 3 times more likely to have a successful short-term (≥1 year) outcome.

Assessment of Outcomes After Multisurface Osteochondral Allograft Transplantations in the Knee.

Background: Treatment of multisurface articular cartilage lesions of the knee is a challenging problem. Hypothesis: Large multisurface cartilage defects in the knee can be successfully managed with transplantation of high chondrocyte viability osteochondral allografts (OCAs) to result in statistically significant improvements in patient-reported outcome measures of pain and function. Study Design: Cohort study; Level of evidence, 3. Methods: Patients were prospectively enrolled into a registry to follow outcomes after OCA transplantation. The study included patients who received OCA transplantation for multisurface unipolar defects in 1 knee and had minimum 2-year follow-up data, including patient-reported outcome measures, failures, reoperations, and complications. The OCA transplants had been stored using 2 methods: standard preservation (SP) or Missouri Osteochondral Preservation System (MOPS). Preoperative data were compared with outcomes at 1 year and final follow-up, and risk factors for revision surgery or failure (total knee arthroplasty) were analyzed. Results: The sample included 25 patients with a mean age of 37.2 years (range, 13-51 years), body mass index of 27.7 (range, 18-38), and follow-up of 45.1 months (median, 49 months; range, 24-68 months). OCAs stored using SP were transplanted into 6 patients, and those stored using MOPS were transplanted into 19 patients. The initial success rate was significantly higher for MOPS OCAs (94.7%) than SP OCAs (33.3%). There were statistically significant improvements in all patient-reported outcomes at 1 year and final follow-up in the MOPS cohort (P < .0001 for all). Revision surgery/failure was significantly associated with patients who were nonadherent to the prescribed postoperative restrictions and rehabilitation protocols (P = .038; odds ratio = 13.5) and with OCAs that had a viable chondrocyte density <70% of the established reference range mean at transplantation (P = .0037; odds ratio = 76). Conclusion: OCA transplantation for treatment of large multisurface cartilage defects in the knee resulted in a 94.7% initial success rate when grafts with high viable chondrocyte density (≥70%) were used and when patients strictly adhered to prescribed postoperative rehabilitation protocols. Successful outcomes were associated with statistically significant improvements in patient-reported outcome measures of pain and function.

Incidence and Cost of Surgical Site Infections After Osteochondral Allograft Transplantation and Meniscal Allograft Transplantation in the Knee.

Background: Surgical site infections (SSIs) significantly influence outcomes and health care costs after orthopaedic surgery, but they have not been well characterized for osteochondral allograft (OCA) transplantation with or without meniscal allograft transplantation (MAT). Purpose: To characterize the incidence, cost, and risk factors associated with potential or confirmed SSIs after large single-surface, multisurface, or bipolar allograft transplantation in the knee. Study Design: Case-control study; Level of evidence, 3. Methods: Prospectively collected registry data were analyzed for patients who underwent primary or revision OCA transplantation with or without MAT in the knee. The Centers for Disease Control and Prevention (CDC) guidelines were used to define SSIs and calculate the SSI incidence. Both potential and confirmed SSIs were analyzed to determine related treatment methods, calculate associated health care costs, and characterize risk factors based on the OCA surgery type (single-surface, multisurface, bipolar, ±MAT), American Society of Anesthesiologists physical status classification system, surgery duration, length of stay, age, sex, body mass index (BMI), and current tobacco use. Results: A total of 224 patients were included in the analysis. There were 2 SSIs in 1 patient that met CDC criteria, such that the incidence for this patient population was 0.9%. An additional 7 patients (3.1%) were examined for potential infections not classified as SSIs. Patients with potential or confirmed SSIs had a significantly higher mean BMI compared to patients with no evidence of an SSI (P <.001). BMI >35 (odds ratio, 9.1) and tobacco use (odds ratio, 6.6) were associated with greater odds for a potential or confirmed SSI. The mean health care costs were $6101 for patients who required additional emergency room visits and/or irrigation and debridement within 90 days postoperatively for potential or confirmed SSIs, $19 for patients with potential superficial incisional SSIs, and $12,100 for patients who experienced a potential or confirmed deep incisional or organ/space SSI >90 days from surgery. Conclusion: Large OCA transplantation with and without MAT were associated with a low incidence of confirmed SSIs (0.9%), and patients with BMI >35 and current tobacco use had greater odds of an SSI. Potential and confirmed SSIs were associated with unscheduled appointments, additional surgical procedures, and higher costs.

Development and Assessment of Novel Multiligament Knee Injury Reconstruction Graft Constructs and Techniques.

Multiligament knee injury (MLKI) typically requires surgical reconstruction to achieve the optimal outcomes for patients. Revision and failure rates after surgical reconstruction for MLKI can be as high as 40%, suggesting the need for improvements in graft constructs and implantation techniques. This study assessed novel graft constructs and surgical implantation and fixation techniques for anterior cruciate ligament (ACL), posterior cruciate ligament (PCL), posterior medial corner (PMC), and posterior lateral corner (PLC) reconstruction. Study objectives were (1) to describe each construct and technique in detail, and (2) to optimize MLKI reconstruction surgical techniques using these constructs so as to consistently implant grafts in correct anatomical locations while preserving bone stock and minimizing overlap. Cadaveric knees (n = 3) were instrumented to perform arthroscopic-assisted and open surgical creation of sockets and tunnels for all components of MLKI reconstruction using our novel techniques. Sockets and tunnels with potential for overlap were identified and assessed to measure the minimum distances between them using gross, computed tomographic, and finite element analysis-based measurements. Percentage of bone volume spared for each knee was also calculated. Femoral PLC-lateral collateral ligament and femoral PMC sockets, as well as tibial PCL and tibial PMC posterior oblique ligament sockets, were at high risk for overlap. Femoral ACL and femoral PLC lateral collateral ligament sockets and tibial popliteal tendon and tibial posterior oblique ligament sockets were at moderate risk for overlap. However, with careful planning based on awareness of at-risk MLKI graft combinations in conjunction with protection of the socket/tunnel and trajectory adjustment using fluoroscopic guidance, the novel constructs and techniques allow for consistent surgical reconstruction of all major ligaments in MLKIs such that socket and tunnel overlap can be consistently avoided. As such, the potential advantages of the constructs, including improved graft-to-bone integration, capabilities for sequential tensioning of the graft, and bone sparing effects, can be implemented.

Is It Cost Effective to Obtain Fungal and Acid-Fast Bacillus Cultures during Spine Debridement?

STUDY DESIGN: Retrospective study. PURPOSE: To identify the rate of positive acid-fast bacillus (AFB) and fungal cultures during spine debridement, determine whether these infections are more common in certain spine segments, identify comorbidities associated with these infections, and determine whether the universal performance of fungal and AFB cultures during spine debridement is cost effective. OVERVIEW OF LITERATURE: Spine infections are associated with significant morbidity and costs. Spine fungal and AFB infections are rare, but their incidence has not been well documented. As such, guidance regarding sample procurement for AFB and fungal cultures is lacking. METHODS: A retrospective review of medical record data from patients undergoing spine irrigation and debridement (I&D) at the University of Missouri over a 10-year period was performed. RESULTS: For patients undergoing spine I&D, there was a 4% incidence of fungal infection and 0.49% rate of AFB infection. Steroid use was associated with a higher likelihood (odds ratio, 5.62; 95% confidence interval, 1.33-23.75) of positive fungal or AFB cultures. Although not significant, patients undergoing multiple I&D procedures had higher rates of positive fungal cultures during each subsequent I&D. Over a 10-year period, if fungal cultures are obtained for each patient, it would cost our healthcare system $12,151.58. This is compared to an average cost of $177,297.64 per missed fungal infection requiring subsequent treatment. CONCLUSIONS: Spine fungal infections occur infrequently at a rate of 4%. Physicians should strongly consider obtaining samples for fungal cultures in patients undergoing spine I&D, especially those using steroids and those undergoing multiple I&Ds. Our AFB culture rates mirror the false positive rates seen in previous orthopedic literature. It is unlikely to be cost effective to send for AFB cultures in areas with low endemic rates of AFB.

Biomechanical assessment of lateral ulnar collateral ligament repair and reconstruction with or without internal brace augmentation.

BACKGROUND: Surgical treatment of posterolateral rotatory instability (PLRI) using primary repair or reconstruction of the lateral collateral ligament complex have proven inconsistent. This study aimed to test the hypothesis that augmentation of LUCL repair or palmaris longus tendon reconstruction using a suture tape augmentation would be associated with less rotational displacement and greater torque load to failure (LTF) compared with nonaugmented constructs. METHODS: Cadaveric elbows (n = 12 matched pairs) were used. Baseline stiffness and displacement values were obtained. The LUCL was transected followed by repair alone, repair with augmentation, reconstruction with palmaris longus graft, or reconstruction with augmentation. Specimens were retested including torque LTF. Paired t tests were performed to assess the biomechanical effects of augmentation. RESULTS: Augmentation was associated with higher LTF than repair and reconstruction alone (P = .008 and .047, respectively). Displacement was less with augmentation in reconstruction groups (P = .048) but not in repair groups. Suture tape augmentation maintained rotational stiffness better than repair alone (P = .01). Although reconstruction with augmentation maintained rotational stiffness better than nonaugmented reconstruction, the differences were not statistically significant (P = .057). Mode of failure for repair alone was predominantly suture pulling through repaired ligament. Augmented repairs primarily failed at the anchor-bone interface. Modes of failure for both reconstruction groups were similar, including graft tearing and/or slipping at the anchor. CONCLUSION: When positioned in neutral forearm rotation and 90o of flexion to simulate postoperative conditions, augmentation of LUCL repair or tendon reconstruction using suture tape is associated with better resistance to rotational loads compared with nonaugmented repair or reconstruction, while maintaining near-native rotational stiffness.

Prospective Assessment of Outcomes After Primary Unipolar, Multisurface, and Bipolar Osteochondral Allograft Transplantations in the Knee: A Comparison of 2 Preservation Methods.

BACKGROUND: Articular cartilage lesions in the knee remain a challenging clinical problem. HYPOTHESIS: A novel graft preservation method combined with surgical technique and patient management improvements would lead to consistently successful outcomes after osteochondral allograft (OCA) transplantation. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: With institutional review board approval and informed consent, patients were prospectively enrolled into a registry to follow outcomes after OCA transplantation. Patients were included when ≥1-year follow-up data were available, including complications and reoperations, patient-reported outcome measures (PROMs), compliance with rehabilitation, revisions, and failures. RESULTS: For patients meeting inclusion criteria (N = 194), mean ± SD age was 37.9 ± 12.2 years and mean BMI was 28.9 ± 5; 38% received unipolar transplants (44% multisurface) and 62% received bipolar transplants. OCAs were preserved by standard tissue bank methods (standard preservation [SP]; 29%) or the novel method (Missouri Osteochondral Preservation System [MOPS]; 71%). Initial success rates were 79% for all cases combined, 60% for SP, and 84% for MOPS. MOPS cases were significantly (P = .028) more likely to be associated with successful outcomes when compared with SP cases. PROMs improved significantly (P < .05) for all cohorts through 3 to 4 years of follow-up. Revisions were performed in 19 cases (10%). MOPS grafts were associated with a significantly (P = .0014) lower revision rate (5%) than SP grafts (21%). Failures occurred in 26 patients (13%), with all undergoing total knee arthroplasty. Bipolar cases were significantly (P = .008) more likely to be associated with failure. MOPS grafts were associated with a significantly (P = .048) lower failure rate (11%) than were SP grafts (19%). Noncompliance with the prescribed rehabilitation protocol was significantly (P = .00008) more likely to be associated with failure. CONCLUSION: Prospective data for 194 cases revealed that OCA transplantation for unipolar, multisurface, and bipolar cartilage restoration can be associated with consistently successful outcomes. The 5% revision rate, 11% failure rate, 82%-94% survival probability estimates, and continually improving PROMs through postoperative 3 to 4 years underscore major advances in outcomes as compared with previous reports. These encouraging results were realized with the use of a novel graft preservation method; autogenous bone marrow concentrate pretreatment of donor bone; advancements in graft cutting, implantation, and stabilization techniques; and procedure-specific rehabilitation protocols.

Histologic assessment of ligament vascularity and synovitis in dogs with cranial cruciate ligament disease.

OBJECTIVE: To assess the relationship between histologic degeneration of cranial cruciate ligaments (CCLs) and severity of synovitis and ligament vascularity. SAMPLE: CCL and synovium from 59 stifle joints (53 dogs). PROCEDURES: CCL and synovium specimens were obtained from stifle joints of juvenile (15 joints; 12 dogs) and adult (25 joints; 22 dogs) dogs with intact CCLs and dogs with CCL rupture (rCCL; 19 joints; 19 dogs). Vascular density and degenerative changes of the CCL core region and severity of synovitis were semiquantitatively evaluated. Relationships were analyzed by use of a random effects model to account for correlated specimens. RESULTS: Mean ± SD modified Bonar scores (scale, 0 to 9) of adults (4.85 ± 0.44) and dogs with rCCL (5.69 ± 0.49) were significantly higher than scores of juveniles (1.13 ± 0.55). Vascularity scores (scale, 0 to 3) were significantly higher for juveniles (3.00 ± 0.24) than for adults (1.53 ± 0.27) and dogs with rCCL (0.78 ± 0.23). Synovitis scores were not significantly different among groups. There was a significant negative relationship between modified Bonar scores and vascularity scores for juveniles and adults and for adults and dogs with rCCL when controlling for age, but there was not a significant relationship between modified Bonar scores and synovitis scores. There was a significant relationship between modified Bonar scores and body weight of adults. CONCLUSIONS AND CLINICAL RELEVANCE: Poor blood supply to the core region could be an important underlying condition for spontaneous degeneration of the CCL in at-risk dogs.

Assessment of Reamer Irrigator Aspirator System (RIA) filtrate for its osteoinductive potential in a validated animal model.

PURPOSE: Previous studies indicate that Reamer Irrigator Aspirator (RIA) filtrate contains proteins that have the potential to stimulate bone healing. This study aimed to determine the osteoinductive capabilities of RIA filtrate in a validated in vivo model. METHODS: With Institutional Review Board approval, RIA filtrates from 9 patients were collected. The filtrate was processed to remove cells and inorganic particles. A portion of each sample was set aside for protein analysis while the remainder was lyophilized and prepared for implantation. With Animal Care and Use Committee approval, athymic mice (n = 16; 32 hind limbs) were randomly assigned to 1 of 4 groups (n = 8 limbs per group) for percutaneous gastrocnemius muscle injection of demineralized bone matrix (DBM) (10 mg), lyophilized RIA powder (10 mg), RIA liquid (10 mg of lyophilized RIA powder in 100ul phosphate buffered saline (PBS)), or DBM (10 mg) + RIA liquid (10 mg in 100ul PBS). Radiographs were obtained 2, 4, and 8 weeks after injection. At 8 weeks, mice were sacrificed and the entire gastrocnemius muscle from each hind limb was collected and processed for histologic examination. Histological sections and radiographs were assessed for ossification/calcification. Data were compared for statistically significant (p < 0.05) differences among groups and strong (R > 0.7) correlations between outcome measures. RESULTS: The protein composition of RIA filtrates was consistent among patients and matched previous data. For all groups, radiographic scores were significantly (p < 0.014) higher (more calcification/ossification) at 8 weeks compared to 2 weeks. Radiographic scores for the DBM and DBM + RIA liquid groups were significantly higher than RIA liquid and RIA powder at 4 weeks and 8 weeks (p < 0.019 and p < 0.049, respectively). Histologic scores were significantly (p = 0.004) higher in the DBM + RIA liquid group compared to the RIA liquid group at 8 weeks. Histologic scores showed strong correlations (r > 0.77) to radiographic scores for all groups. CONCLUSION: RIA filtrate liquid and powder were osteoinductive in vivo with new bone formation being most abundant using a combination of DBM and RIA filtrate in this validated animal model. RIA filtrate has potential for clinical use in augmenting bone healing treatments.

Day of Week and Surgery Location Effects on Stay Length and Cost for Total Joint Arthroplasty: Academic versus Orthopaedic-Specific Hospital.

Demand for total hip (THA) and knee arthroplasties (TKA) is expected to rise sharply by 2030. Increasing demand in conjunction with financial pressure requires the use of cost-effective total joint arthroplasty (TJA) strategies. This study examined the effects that day of week and surgery location [academic (AH) versus orthopaedic-specific (OsH) hospital] have on length of stay (LOS) and cost for primary TJA patients in one multihospital university-based medical center. An Institutional Review Board-approved database of adult patients undergoing primary THA or TKA from June 2013 to December 2014 was constructed. Surgery location, day of procedure, age, American Society of Anesthesiologists (ASA) classification, LOS, and cost were recorded for each patient. Data were compared for significant differences using analysis of variance, t-Test or rank sum and for strength of correlations using Pearson's or Spearman's tests. A total of 1,291 patients met inclusion criteria. OsH showed significantly lower cost and shorter LOS than AH. Wednesday surgeries had significantly higher cost and longer LOS than all other days. Friday surgeries had significantly lower cost and shorter LOS than other days. ASA 3 and 4 were associated with the highest cost and longest LOS. LOS had a moderately strong direct correlation to cost. ASA did not have a strong correlation with LOS or cost. Data separated for THA and TKA showed similar results. At our institution, OsH provides more consistent and lower LOS and cost across all ASA classes. Wednesday and Thursday surgeries have increased LOS and cost than other days, which may be due to weekend discharge difficulties (average LOS is 3.0 days).

Identification of Synovial Fluid Biomarkers for Knee Osteoarthritis and Correlation with Radiographic Assessment.

Osteoarthritis (OA) is a costly and debilitating condition that is typically not diagnosed early enough to prevent progression of disease. The purpose of this study was to evaluate synovial fluid from knees with and without OA for potential markers of joint inflammation and degradation and to correlate these findings with radiographic severity of disease. With Institutional Review Board approval, synovial fluid samples were collected before the patient undergoing total knee arthroplasty. Control knees (n = 3) were patients younger than 30 years of age with no history of anterior cruciate ligament, posterior cruciate ligament, or meniscal injury, and no surgical history for either knee. Weight-bearing, anterior-posterior radiographic views were used to determine radiographic OA severity using the modified Kellgren and Lawrence scale. Synovial fluid samples from 18 patients (21 knees) were analyzed using a multiplex assay. Matrix metalloproteinase (MMP)-1 (p < 0.001), interleukin (IL)-6 (p < 0.013), IL-8 (p < 0.024), and Chemokine (C-C motif) ligand 5 (CCL5) (p < 0.006) were significantly higher in the synovial fluid of OA patients compared with normal patients. The radiographic score was significantly higher in patients with OA compared with normal knees (p < 0.002). MMP-1 had a moderate positive correlation with MMP-2, IL-6, IL-8, and CCL5. IL-6 had a strong positive correlation with IL-8 and a moderate positive correlation with MMP-2. Monocyte chemotactic protein 1 had a moderate positive correlation with IL-6 and a strong positive correlation with IL-8. Radiographic scores had a strong positive correlation with IL-6 and IL-8 and a moderate positive correlation with MCP-1. These data provide novel and clinically relevant information for the investigation of synovial fluid biomarkers for knee OA.

Assessment of cellular, biochemical, and histologic effects of bipolar radiofrequency treatment of canine articular cartilage.

OBJECTIVE: To assess the cellular, biochemical, and histologic effects of bipolar radiofrequency-generated heat on canine articular cartilage. SAMPLE POPULATION: Articular cartilage explants (n = 72) from 6 canine cadavers and cultured articular chondrocytes from 5 canine cadavers. PROCEDURE: Cartilage explants were randomly assigned to receive no treatment or treatment with focal (3 seconds) or diffuse bipolar radiofrequency. Following treatment, methylene blue permeability assay was performed (n = 12) and remaining samples (60) were cultured. Immediately and 5, 10, and 20 days after treatment, cultured explants were assessed for glycosaminoglycan (GAG) and collagen contents, type II collagen and matrix metalloproteinase (MMP)-13 immunoreactivity, and modified Mankin histologic scores. Liquid culture media were collected every 4 days and GAG content measured. Additionally, cultured chondrocytes were exposed for 3 seconds to media preheated to 37 degrees, 45 degrees, or 55 degrees C. Cell viability was determined via 2 different assays immediately and 24 hours after treatment. RESULTS: Radiofrequency-treated cartilage had reduced permeability and considerable histologic damage, compared with control samples; most treated samples had reduced collagen II staining and increased MMP-13 immunostaining. Compared with other treatments, less GAGs were released from cartilage after diffuse radiofrequency treatment throughout the study period. Cell viability was significantly different between controls and cells treated at 55 degrees C immediately and 24 hours after heat treatment. CONCLUSIONS AND CLINICAL RELEVANCE: In this study, bipolar radiofrequency treatment had detrimental effects on normal articular cartilage cells and extracellular matrix with probable long-term clinical consequences. The usefulness of radiofrequency for treatment of osteoarthritic articular cartilage requires further investigation.

Canine synovial sarcoma: a retrospective assessment of described prognostic criteria in 16 cases (1994-1999).

Pertinent patient data and biopsied tissue from 16 cases of canine synovial sarcoma (SS) were reviewed. Histopathological grade, clinical stage, and tissue immunoreactivity to cytokeratin (broad stain, AE1/AE3 and cytokeratin 7) and vimentin were determined and correlated with survival. Effect of treatment on survival was similarly evaluated. Neither clinical stage nor histopathological grade significantly affected survival patterns. Tissues from all cases stained >30% positively with vimentin, whereas no tissue from any case exhibited cytokeratin immunoreactivity. Dogs receiving surgical tumor excision or amputation had a significantly higher survivability than those receiving no treatment (P<0.02). Treatment aggressiveness may be more appropriate than clinical staging or tumor grading in predicting survival. Reliability of diagnosing and prognosticating canine SS with current immunohistochemistry protocols should be questioned.