Alison P. Toth

Graft size and patient age are predictors of early revision after anterior cruciate ligament reconstruction with hamstring autograft.

PURPOSE To evaluate whether decreased hamstring autograft size and decreased patient age are predictors of early graft revision. METHODS Of 338 consecutive patients undergoing primary anterior cruciate ligament (ACL) reconstruction with hamstring autograft, 256 (75.7%) were evaluated. Graft size and patient age, gender, and body mass index at the time of ACL reconstruction were recorded, along with whether subsequent ACL revision was performed. RESULTS The 256 patients comprised 136 male and 120 female patients and ranged in age from 11 to 52 years (mean, 25.0 years). The mean follow-up was 14 months (range, 6 to 47 months). Revision ACL reconstruction was performed in 18 of 256 patients (7.0%) at a mean of 12 months after surgery (range, 3 to 31 months). Revision was performed in 1 of 58 patients (1.7%) with grafts greater than 8 mm in diameter, 9 of 139 patients (6.5%) with 7.5- or 8-mm-diameter grafts, and 8 of 59 patients (13.6%) with grafts 7 mm or less in diameter (P = .027). There was 1 revision performed in the 137 patients aged 20 years or older (0.7%), but 17 revisions were performed in the 119 patients aged under 20 years (14.3%) (P < .0001). Most revisions (16 of 18) were noted to occur in patients aged under 20 years with grafts 8 mm in diameter or less, and the revision rate in this population was 16.4% (16 of 97 patients). Age less than 20 years at reconstruction (odds ratio [OR], 18.97; 95% confidence interval [CI], 2.43 to 147.06; P = .005), decreased graft size (OR, 2.20; 95% CI, 1.00 to 4.85; P = .05), and increased follow-up time (OR, 1.07; 95% CI, 1.02 to 1.12) were associated with increased risk of revision. CONCLUSIONS Decreased hamstring autograft size and decreased patient age are predictors of early graft revision. Use of hamstring autografts 8 mm in diameter or less in patients aged under 20 years is associated with higher revision rates. LEVEL OF EVIDENCE Level III, retrospective comparative study.

Provider volume of total knee arthroplasties and patient outcomes in the HCUP-Nationwide Inpatient Sample

BACKGROUND The relationship between volume and outcome of total knee arthroplasties has never been evaluated in a nationally representative sample, to our knowledge. We hypothesized that surgeons and hospitals with higher patient volumes would have better outcomes, as defined by lower mortality rates, shorter hospital stays, and lower postoperative complication rates. METHODS The 1997 Healthcare Cost and Utilization Project (HCUP) Nationwide Inpatient Sample, Release 6, provided discharge abstracts of patients undergoing total knee arthroplasty from a national stratified probability sample. Logistic and multiple regression models were used to estimate the adjusted association of surgeon or hospital volume with rates of in-hospital mortality, pulmonary thromboembolism, deep venous thrombosis in the lower extremity, and postoperative wound infection as well as length of hospital stay. Estimates were calculated for a target population of 277,550 patients. Models were adjusted for comorbidity, age, gender, race, household income, and procedure (primary or revision arthroplasty). RESULTS The patients were mostly white (70.2%) and female (62.7%), with a mean age of 68.9 years. The overall in-hospital mortality rate for the target population was 0.2%, and the average length of stay was 4.6 days for the primary total knee arthroplasties and 4.9 days for the revision procedures. Surgeon volumes of at least fifteen procedures per year and hospital volumes of at least eighty-five per year were significantly and linearly associated with lower mortality rates (odds ratio = 0.56 [0.24 to 1.31] for surgeon volume of > or = 60). No other association demonstrated a significant and directionally consistent linear trend for improved outcomes. CONCLUSION Patients treated by providers with lower caseload volumes had higher rates of mortality following total knee arthroplasty in 1997. Proposing volume standards could decrease patient mortality following this procedure.

Dermal Tissue Allograft for the Repair of Massive Irreparable Rotator Cuff Tears

Background: Massive irreparable rotator cuff tears in patients without advanced glenohumeral arthritis can pose a challenge to surgeons. Numerous management strategies have been utilized, and studies have shown varied results with regard to shoulder pain, range of motion, strength, and overall function. Hypothesis: Patients undergoing repair of massive irreparable rotator cuff tears through a mini-open approach with the use of human dermal tissue matrix allograft would demonstrate an improvement in pain, range of motion, strength, and subjective functional outcomes. Study Design: Case series; Level of evidence, 4. Methods: We performed a prospective observational study of 24 patients who underwent interposition repair of massive rotator cuff tears using human dermal allograft. All patients were evaluated preoperatively and postoperatively by the treating surgeon. Data were collected preoperatively and postoperatively for an average 3-year follow-up period (range, 29-40 months). Active range of motion as well as supraspinatus and infraspinatus strength was assessed. Subjective outcome measures included pain level (visual analog scale of 0-10, with 10 = severe pain), American Shoulder and Elbow Score (ASES), and Short-Form 12 (SF-12) score. Imaging evaluation to assess for repair integrity was performed using static and dynamic ultrasonography at final follow-up. Results: Mean pain level decreased from 5.4 to 0.9 (P = .0002). Mean active forward flexion and external rotation motion improved from 111.7° to 157.3° (P = .0002) and from 46.2° to 65.1° (P = .001), respectively. Mean shoulder abduction improved from 105.0° to 151.7° (P = .0001). Supraspinatus and infraspinatus strength improved from 7.2 to 9.4 (P = .0003) and from 7.8 to 9.3 (P = .002), respectively. Mean ASES improved from 66.6 to 88.7 (P = .0003). Mean SF-12 scores improved from 48.8 to 56.8 (P = .03). One partial graft retear occurred because of patient noncompliance during postoperative rehabilitation. However, this patient still demonstrated improvement in pain, motion, and subjective outcomes at final follow-up. Ultrasonography demonstrated “fully intact” repairs in 76% of patients. All remaining patients had “partially intact” repairs. There were no complete tears. Conclusion: In our series of carefully selected candidates, all patients demonstrated a significant improvement in pain, range of motion, and strength. Subjective outcome measures, including mean ASES and SF-12 scores, also demonstrated significant improvement at an average 3-year follow-up.

Association between Ratio of Matrix Metalloproteinase-1 to Tissue Inhibitor of Metalloproteinase-1 and Local Recurrence, Metastasis, and Survival in Human Chondrosarcoma*

Chondrosarcoma, a malignant cartilage-forming mesenchymal tumor, displays a wide range of clinical behavior that can be difficult to predict with histological analysis. Matrix metalloproteinases contribute to the processes of local invasion and metastasis by controlling the ability of a tumor to transverse tissue boundaries. The specificity of matrix metalloproteinase-1 (interstitial collagenase) for fibrillar collagen may be central to those processes. Matrix metalloproteinase-2 facilitates invasion by degradation of such basement-membrane structures as type-IV collagen. The balance between the activity of tissue inhibitors of metalloproteinase and the activity of matrix metalloproteinase determines the proteolytic activity and may, in part, determine the overall invasiveness and potential for metastasis. The measurement of the ratio of matrix metalloproteinase to tissue inhibitor of metalloproteinase may have prognostic value for determining whether individual chondrosarcomas are locally invasive or will metastasize. Furthermore, there may be a specific pattern of expression of matrix metalloproteinase and tissue inhibitor of metalloproteinase in chondrosarcomas that is related to local invasion and probability of metastasis. Sixteen paraffin-embedded archival specimens of tumors were examined. Six twenty-micrometer-thick sections were cut from each tumor, and the amounts of cDNA formed from the mRNA were determined with reverse transcription-polymerase chain reaction with use of novel primers for matrix metalloproteinase-1, matrix metalloproteinase-2, tissue inhibitor of metalloproteinase-1, and tissue inhibitor of metalloproteinase-2. The amounts of cDNA for the matrix metalloproteinases and their inhibitors were determined by chemiluminescence and band densitometry. The ratio of the amount of cDNA for matrix metalloproteinase-1 to that for its tissue inhibitor and the ratio of the amount of cDNA for matrix metalloproteinase-2 to that for its tissue inhibitor were calculated, and the results were compared with use of the Student t test, enabling log-rank analysis of Kaplan-Meier survival curves. These ratios as well as the age and gender of the patient; the grade, size, and location of the tumor; the type of adjuvant therapy; and the operative margins were examined for significance with use of stepwise logistic-regression analysis. The patients who had recurrent disease had a significantly higher (p < 0.003) ratio of matrix metalloproteinase-1 to tissue inhibitor of metalloproteinase-1 (mean, 0.939; range, 0.647 to 1.101) than the patients who were free of disease (mean, 0.703; range, 0.629 to 0.772). Moreover, there was a striking difference between the Kaplan-Meier survival curve associated with a high ratio (more than 0.8) and that associated with a low ratio (p = 0.0015). The mean ratio of matrix metalloproteinase-2 to tissue inhibitor of metalloproteinase-2 was 1.814 (range, 1.206 to 3.77) in the patients who had recurrent disease compared with 1.473 (range, 1.073 to 2.390) in those who were free of disease; this difference was not found to be significant, with the numbers available. Analysis of the survival curves indicated that a worse prognosis was associated with a high ratio, but again this relationship was not found to be significant. Regression analysis revealed that a high ratio of matrix metalloproteinase-1 to its tissue inhibitor was a moderately significant independent predictor of a poor outcome (&agr; = 0.07). CLINICAL RELEVANCE: A high ratio of matrix metalloproteinase-1 to tissue inhibitor of metalloproteinase-1 in human chondrosarcoma may be indicative of a more invasive and aggressive tumor and a worse prognosis. The data presented here suggest that concentrations of matrix metalloproteinase-1, with substrate specificity for fibrillar collagens, may be important in the pathogenesis of local invasiveness and metastasis in human chondrosarcoma. The methods described in the present report may be useful for prognostically stratifying the survival of patients who have chondrosarcoma and for identifying a mechanism for the selection of adjuvant therapy in the future.

Isokinetic Strength, Endurance, and Subjective Outcomes After Biceps Tenotomy Versus Tenodesis A Postoperative Study

Background: Similar subjective outcomes have been reported for tenotomy or tenodesis of the long head of the biceps. Few studies have reported on postoperative strength and endurance. Hypothesis: Biceps tenodesis results in superior subjective outcomes, strength, and endurance compared with tenotomy. Study Design: Cohort study; Level of evidence, 3. Methods: Participants completed isokinetic strength and endurance testing for elbow flexion and supination on the operative and nonoperative sides a minimum of 2 years after biceps tenotomy or tenodesis. Modified American Shoulder and Elbow Surgeons (MASES) and Single Assessment Numeric Evaluation (SANE) scores were obtained. The operative/nonoperative strength and endurance scores were compared for the tenotomy and tenodesis groups, with the nonoperative shoulder serving as the control for each participant’s operative shoulder. Change scores for strength and endurance were reported as percentage increase or decrease as compared with the nonoperative side. Change scores and MASES and SANE scores were compared between the 2 groups. The presence of a “popeye” deformity or pain at the tenodesis site was noted. Results: Thirty-five patients (19 tenotomy, 16 tenodesis) were studied. No significant difference was noted in postoperative MASES and SANE scores. Operative-side peak supination torque was significantly decreased relative to the nonoperative side in the tenotomy group, which had a significantly larger decrease in supination peak torque than did the tenodesis group on comparison of change scores. No significant difference was noted for peak flexion torque or flexion/supination endurance between operative and nonoperative sides in either group or between change scores for peak flexion torque or flexion/supination endurance in the tenotomy and tenodesis groups. Four tenotomy patients had a popeye deformity, 2 of whom reported painful cramping. Two patients had pain at the tenodesis site. Conclusion: Subjective outcomes are similar for patients treated with tenotomy and tenodesis. Tenotomy decreases supination peak torque relative to the nonoperative side and tenodesis.

Massive or 2-Tendon Rotator Cuff Tears in Active Patients With Minimal Glenohumeral Arthritis Clinical and Radiographic Outcomes of Reconstruction Using Dermal Tissue Matrix Xenograft

Background: The management of irreparable massive or full-thickness 2-tendon rotator cuff tears in active patients with minimal glenohumeral arthritis remains a difficult challenge for the treating surgeon. Many different treatment options, with varied success, have been proposed. Hypotheses: (1) Patients undergoing reconstruction of irreparable massive or full-thickness 2-tendon rotator cuff tears by dermal tissue matrix xenograft would demonstrate improvements in pain, range of motion, strength, and subjective functional outcomes. (2) Postoperative ultrasonography would demonstrate intact repairs at a minimum 2-year follow-up. Study Design: Case series; Level of evidence, 4. Methods: Twenty-six patients (27 shoulders) underwent reconstruction of irreparable massive or full-thickness 2-tendon rotator cuff tears by dermal tissue matrix xenograft. Pain level (scale 0-10, 10 = severe pain), active range of motion, and supraspinatus and external rotation strength were assessed. Subjective outcome measures included American Shoulder and Elbow Score (ASES) and Short Form-12 (SF-12) score. Clinical and radiographic analyses were performed at an average 32-month follow-up period (minimum 2-year follow-up). Ultrasound imaging (static and dynamic) of the operative shoulder was performed at final follow-up to assess the integrity of the construct. Results: Mean patient age was 60 years. Mean pain level decreased from 5.1 to 0.4 (P = .002). Mean active forward flexion and abduction improved from 138.8° to 167.3° (P = .024) and 117.9° to 149.3° (P = .001), respectively. Supraspinatus and external rotation strength improved from 7.2 to 9.4 (P = .001) and 7.4 to 9.5 (P = .001), respectively. Mean ASES improved from 62.7 to 91.8 (P = .0007), and mean SF-12 scores improved from 48.4 to 56.6 (P = .044). Twenty-one patients (22 shoulders) returned for a dynamic and static ultrasound of the operative shoulder at a minimum 2-year follow-up. Sixteen patients (73%) demonstrated a fully intact tendon-graft reconstruction, 5 patients (22%) had a partially intact reconstruction, and 1(5%) had a complete tear at the graft-bone interface caused by suture anchor pullout as a result of a fall. There were no cases of infection or tissue rejection. Conclusion: Active patients with massive or 2-tendon rotator cuff tears with minimal glenohumeral arthritis continue to be a subset of the population for whom there is no current standard of care. Results suggest that the use of porcine xenograft may be an effective means by which to treat these patients.

MRI Appearance of Posterior Cruciate Ligament Tears

OBJECTIVE There is little in the radiology literature regarding the MRI appearance of a torn posterior cruciate ligament (PCL). The purpose of this study was to describe the MRI appearance of surgically proven PCL tears and to emphasize previously unreported signs. CONCLUSION The PCL is usually injured as the result of stretching deformation; on MRI, the ligament maintains continuity as a single structure with apparent thickening. On sagittal T2-weighted images, an anteroposterior diameter of 7 mm or more is highly suggestive of a torn PCL. Increased intrasubstance signal intensity in the PCL on proton-density images with lower signal intensity on T2-weighted images is another common feature.

Stem cell therapies for knee cartilage repair: the current status of preclinical and clinical studies.

Background: Articular cartilage damage of the knee is common, causing significant morbidity worldwide. Many adult tissues contain cells that are able to differentiate into multiple cell types, including chondrocytes. These stem cells have gained significant attention over the past decade and may become frontline management for cartilage defects in the very near future. Purpose: The role of stem cells in the treatment of knee osteochondral defects was reviewed. Recent animal and clinical studies were reviewed to determine the benefits and potential outcomes of using stem cells for cartilage defects. Study Design: Literature review. Methods: A PubMed search was undertaken. The key phrase “stem cells and knee” was used. The search included reviews and original articles over an unlimited time period. From this search, articles outlining animal and clinical trials were selected. A search of current clinical trials in progress was performed on the clinicaltrials.gov website, and “stem cells and knee” was used as the search phrase. Results: Stem cells have been used in many recent in vitro and animal studies. A number of cell-based approaches for cartilage repair have progressed from preclinical animal studies into clinical trials. Conclusion: The use of stem cells for the treatment of cartilage defects is increasing in animal and clinical studies. Methods of delivery of stem cells to the knee’s cartilage vary from direct injection to implantation with scaffolds. While these approaches are highly promising, there is currently limited evidence of a direct clinical benefit, and further research is required to assess the overall outcome of stem cell therapies for knee cartilage repair.

Interstitial collagenase gene expression correlates with in vitro invasion in human chondrosarcoma

Matrix metalloproteinases contribute to the processes of local invasion and metastasis by providing cells with the ability to traverse tissue boundaries. The levels of gene expression were quantitated for matrix metalloproteinases-1 and tissue inhibitors of metalloproteinases-1 in human chondrosarcoma cell lines, and the results were correlated with cell differentiation, collagenase activity, and in vitro invasion. Three well characterized human cell lines were used in this study, with the level of chondrocytic differentiation confirmed to be JJ012, FS090, and 105KC in increasing order on the basis of aggrecan and collagen gene expression. The matrix metalloproteinases-1/tissue inhibitors of metalloproteinases-1 ratio correlated with the level of differentiation in an inverse fashion. Collagenase activity paralleled matrix metalloproteinases-1/tissue inhibitors of metalloproteinases-1 gene expression and was associated with a more invasive phenotype in an in vitro assay. In this report, matrix metalloproteinase-1 and tissue inhibitors of metalloproteinases-1 expression in human chondrosarcoma tumor cell lines were quantitated, and it was shown that interstitial collagenase gene expression correlates inversely with chondrocytic differentiation. Differences in collagenase activity and in vitro invasion correlate inversely with the level of differentiation. These findings are consistent with the hypothesis that collagenase activity is associated with a poorer prognosis in chondrosarcoma by facilitating cell egress from the tumor matrix.

Pelvic Stress Injuries in the Athlete Management and Prevention

Stress-related injuries of the pelvis are an important consideration in sports medicine. Diagnosis of stress injuries may be difficult and requires a high index of suspicion. Plain radiographs are the first step in imaging but magnetic resonance imaging is the imaging modality of choice for definitive diagnosis. Repetitive forces transferred to the bone, either through muscle fatigue or from the tensile forces generated by the contracting muscles, are thought to be the causative mechanism of stress injuries. Interestingly, the reparative and reorganisational process of bone result in a temporary weakening before ultimately producing a reinforced structure better adept at supporting repetitive stress. This temporary weakness occurs for several weeks after the initiation of a training programme. Knowledge of the mechanism and aetiology of stress injuries provides the foundation for treatment and prevention. Resting the involved bone through modifying the training programme is the mainstay of treatment. Every effort to prevent stress injuries should be made when initiating a training programme. A cyclical training programme, one that does not place continued and undue stress on any one bone, but provides adequate rest for bone recovery, is recommended. Attention to proper nutrition is emphasised for both treatment and prevention. Maintenance of a normal hormonal balance is additionally important in the female athlete. The bone-maintaining properties of estrogen from a normal eumenorrhoeic menstrual cycle should be preserved. Rarely, women may develop an inter-related problem of disordered eating, amenorrhoea and osteoporosis, the female athlete triad. The female athlete triad is a serious problem that may result in a permanent loss of bone mass. This article more fully explains the mechanism of stress injuries to bone, and provides a more detailed discussion of diagnosis, treatment and prevention.