Catherine M. Robertson

Return to Athletic Activity After Osteochondral Allograft Transplantation in the Knee

Background: Fresh-stored osteochondral allografts have been used successfully to resurface large chondral and osteochondral defects of the knee. However, there are limited data available for the return to athletic activity. Purpose: To review the rate of return to athletic activity after osteochondral allograft transplantation in the knee and to identify any potential risk factors for not returning to sport. Study Design: Case series; Level of evidence, 4. Methods: Forty-three athletes were treated with fresh-stored osteochondral allograft transplantation for symptomatic large chondral or osteochondral defects of the knee from 2000 to 2010. The average age of the athletes (30 men, 13 women) was 32.9 years (range, 18-49 years). Patients were prospectively evaluated by International Knee Documentation Committee (IKDC), activities of daily living scale of the Knee Injury and Osteoarthritis Outcome Score (KOOS), Marx Activity Rating Scale, and Cincinnati Sports Activity Scale scores. A multivariable regression analysis was performed to identify potential risk factors for failure to return to sport at the preinjury level. Results: At an average 2.5-year follow-up, limited return to sport was possible in 38 of 43 athletes (88%), with full return to the preinjury level achieved in 34 of 43 athletes (79%). In these 34 athletes, time to return to sport was 9.6 ± 3.0 months. Age ≥25 years (P = .04) and preoperative duration of symptoms greater than 12 months (odds ratio, 37; P = .003) negatively affected the ability to return to sport. In the athletes who returned to their previous level of competition, IKDC (P < .001), KOOS (P = .02), and Marx Activity Rating Scale (P < .001) scores were all significantly greater than in those athletes who did not return to sport. Conclusion: Osteochondral allograft transplantation in an athletic population for chondral and osteochondral defects in the knee allows for a high rate of return to sport. Risk factors for not returning to sport included age ≥25 years and preoperative duration of symptoms ≥12 months.

Analysis of Stored Osteochondral Allografts at the Time of Surgical Implantation

Background To date, the morphological, biochemical, and biomechanical characteristics of articular cartilage in osteochondral allografts that have been stored have not been fully described. Hypothesis Osteochondral allografts procured and stored commercially for a standard period as determined by tissue banking protocol will have compromised chondrocyte viability but preserved extracellular matrix quality. Study Design Controlled laboratory study. Methods Unused cartilage from 16 consecutive osteochondral allografts was sampled during surgery after tissue bank processing and storage. Ten grafts were examined for cell viability and viable cell density using confocal microscopy, proteoglycan synthesis via 35SO4 uptake, and glycosaminoglycan content and compared with fresh cadaveric articular cartilage. Biomechanical assessment was performed on the 6 remaining grafts by measuring the indentation stiffness of the cartilage. Results The mean storage time for the transplanted specimens was 20.3 ± 2.9 days. Chondrocyte viability, viable cell density, and 35SO4 uptake were significantly lower in allografts at implantation when compared to fresh, unstored controls, whereas matrix characteristics, specifically glycosaminoglycan content and biomechanical measures, were unchanged. In addition, chondrocyte viability in the stored allografts was preferentially decreased in the superficial zone of cartilage. Conclusion Human osteochondral allografts stored for a standard period (approximately 3 weeks) before implantation undergo decreases in cell viability, especially in the critically important superficial zone, as well as in cell density and metabolic activity, whereas matrix and biomechanical characteristics appear conserved. The exact clinical significance of these findings, however, is unknown, as there are no prospective studies examining clinical outcomes using grafts stored for extended periods. Clinical Relevance Surgeons who perform this procedure should understand the cartilage characteristics of the graft after 21 days of commercial storage in serum-free media.

Alterations in Internal Rotation and Alpha Angles Are Associated With Arthroscopic Cam Decompression in the Hip

Background: Symptomatic labral tears of the hip are associated with bony abnormalities of the femoral head and acetabulum, resulting in impingement. These patients have characteristic internal rotation limitations, which can result in compensatory athletic injury patterns around the hip, pelvis, and lumbar spine. Hypothesis: Patients undergoing arthroscopic cam decompression will have improvement in internal rotation after decompression. Patients with decreased femoral neck anteversion will have decreased preoperative internal rotation of the hip and show less improvement after cam decompression. Study Design: Cohort study; Level of evidence, 3. Methods: Patients undergoing arthroscopic decompression of cam and pincer lesions of the hip and treatment of labral injury were evaluated for range of motion and bony anatomy by preoperative computed tomography and pre- and postoperative radiographs. Patients were excluded for age older than 40 years, arthritic changes of the joint, and revision setting. Results: Fifty-five patients (56 hips) were treated with selective labral debridement with functional labral preservation (33/56) or selective labral debridement with labral refixation (23/56) and cam decompression. Fifty-one of the 56 had resection of associated pincer lesions. Patients were divided into femoral anteversion subgroups: normal (5°-20°, 34 patients), increased (>20°, 8 patients), and decreased (<5°, 13 patients). Mean patient age was 24.7 ± 6.3 years (range, 14-39 years). Alpha angle, a measure of the head-neck offset, decreased from 68.0° ± 10.0° preoperatively to 43.4° ± 4.0° after decompression (P < .001). Internal rotation of the hip increased from 9.9° ± 6.6° preoperatively to 27.6° ± 6.4° after decompression (P < .001) and 30.1° ± 5.3° at 3 months (P < .001). Hip flexion was not significantly different immediately after decompression but was significantly improved from 115.7° ± 13.3° preoperatively to 127.9° ± 6.6° at 3 months postoperatively (P < .003). Although improvement in internal rotation after decompression increased independent of femoral version, patients with abnormal version had altered internal rotation with increased values associated with increased anteversion (15.7° ± 5.4°/34.3° ± 6.7°) and decreased with relative retroversion (7.1° ± 8.3°/25.2° ± 4.9°; P < .05). Conclusion: Arthroscopic decompression results in improvement of the radiographic alpha angle and normalization of internal rotation in impingement-related disease of the hip. Internal rotation improvements can be achieved even in the setting of femoral retroversion.

Failed Healing of Rotator Cuff Repair Correlates With Altered Collagenase and Gelatinase in Supraspinatus and Subscapularis Tendons

Background: Despite improvements in arthroscopic rotator cuff repair technique and technology, a significant rate of failed tendon healing persists. Improving the biology of rotator cuff repairs may be an important focus to decrease this failure rate. The objective of this study was to determine the mRNA biomarkers and histological characteristics of repaired rotator cuffs that healed or developed persistent defects as determined by postoperative ultrasound. Hypothesis: Increased synovial inflammation and tendon degeneration at the time of surgery are correlated with the failed healing of rotator cuff tendons. Study Design: Case-control study; Level of evidence, 3. Methods: Biopsy specimens from the subscapularis tendon, supraspinatus tendon, glenohumeral synovium, and subacromial bursa of 35 patients undergoing arthroscopic rotator cuff repair were taken at the time of surgery. Expression of proinflammatory cytokines, tissue remodeling genes, and angiogenesis factors was evaluated by quantitative real-time polymerase chain reaction. Histological characteristics of the affected tissue were also assessed. Postoperative (>6 months) ultrasound was used to evaluate the healing of the rotator cuff. General linear modeling with selected mRNA biomarkers was used to predict rotator cuff healing. Results: Thirty patients completed all analyses, of which 7 patients (23%) had failed healing of the rotator cuff. No differences in demographic data were found between the defect and healed groups. American Shoulder and Elbow Surgeons shoulder scores collected at baseline and follow-up showed improvement in both groups, but there was no significant difference between groups. Increased expression of matrix metalloproteinase 1 (MMP-1) and MMP-9 was found in the supraspinatus tendon in the defect group versus the healed group (P = .006 and .02, respectively). Similar upregulation of MMP-9 was also found in the subscapularis tendon of the defect group (P = .001), which was consistent with the loss of collagen organization as determined by histological examination. From a general linear model, the upregulation of MMP-1 and MMP-9 was highly correlated with failed healing of the rotator cuff (R2 = .656). Conclusion: The upregulation of tissue remodeling genes in the torn rotator cuff at the time of surgery provides a snapshot of the biological environment surrounding the torn rotator cuff that is closely related to the healing of repaired rotator cuffs.

Does subchondral bone affect the fate of osteochondral allografts during storage

Background Osteochondral allografts currently are hypothermically stored for a minimum of 14 days to a maximum of 28 days before surgical implantation, making storage conditions increasingly important. Previous studies have suggested that graft deterioration during storage may result from degradative factors and residual marrow elements in the subchondral bone. Hypothesis Allografts stored with large bone-to-cartilage ratios will be compromised after prolonged storage compared with grafts with minimal bone. Study Design Controlled laboratory study. Methods Osteochondral plugs were harvested from 16 fresh human femoral condyles and randomly assigned to 1 of 3 groups based on bone-to-cartilage ratios: 1:1, 5:1, or 10:1. These ratios were considered on the basis that the 1:1 ratio is the minimum bone necessary to press-fit an allograft and 10:1 is the present ratio used by tissue banks for allograft storage. After 14 and 28 days of storage at 4 ° C, the specimens were assessed for viability and viable cell density using confocal microscopy, proteoglycan synthesis by 35SO4 incorporation, and glycosaminoglycan content. Results All grafts underwent a significant decline in viable cell density, proteoglycan synthesis, and chondrocyte viability (particularly in the superficial region) after 14 days of storage, but no differences were observed between the 1:1, 5:1, or 10:1 ratio groups at either day 14 or day 28. In addition, no significant difference was noted in the glycosaminoglycan content in any of the groups. Conclusion Osteochondral allografts stored with a 10:1 bone-to-cartilage ratio, similar to tissue-banking ratios, performed no worse than allografts stored with minimal bone, suggesting that the bone-to-cartilage ratio plays little to no role in the degradation of allografts during prolonged storage. Clinical Relevance As the practice of osteochondral allograft resurfacing becomes more commonplace, it is important that surgeons understand the factors that affect graft quality.

Upregulation of apoptotic and matrix-related gene expression during fresh osteochondral allograft storage.

We identified changes in proapoptotic and extracellular matrix-related gene expression with prolonged storage of fresh osteochondral allografts using gene array analysis to better understand the process of graft degradation during storage. Six human distal femurs were obtained according to standard organ harvesting protocol and stored in serum-free allograft media. Each was examined at baseline (within 72 hours postmortem), 21 days (average time of implantation), and 35 days (maximum time to implantation) for proapoptotic and extracellular matrix-related gene expression using two 100-gene microarrays, cell viability using confocal microscopy, and proteoglycan synthesis via 35SO4 incorporation. We found numerous genes showing upregulation associated with increased storage time, including CD30, CD30 ligand, Fas, Fas ligand, tumor necrosis factor-α, and several caspases. Cell viability and proteoglycan synthesis also were significantly decreased with increased storage. Loss of chondrocytes via apoptosis is likely a key determinant of osteochondral allograft viability during storage, whereas extracellular matrix degeneration may occur at a later stage. These findings provide targets for future media modulation. Improved graft viability and the potential for lengthened storage periods through improved storage conditions may improve clinical outcomes and availability of fresh osteochondral allografts.

Anatomic coracoclavicular and acromioclavicular ligament reconstruction for high-grade acromioclavicular separations: the gracilis weave.

With the gracilis weave, stability of the acromioclavicular joint is achieved via the passage of an autograft in a weaved configuration over and under the acromioclavicular joint via the acromion, recreating the native 4-ligament acromioclavicular capsular structures.

Ultrasound-Guided Percutaneous Peripheral Nerve Stimulation: Neuromodulation of the Femoral Nerve for Postoperative Analgesia Following Ambulatory Anterior Cruciate Ligament Reconstruction: A Proof of Concept Study: FEMORAL NEUROMODULATION AND POSTOP PAIN

The purpose of this prospective proof of concept study was to investigate the feasibility of using percutaneous peripheral nerve stimulation of the femoral nerve to treat pain in the immediate postoperative period following ambulatory anterior cruciate ligament reconstruction with a patellar autograft.