Cells Remain Viable When Collected With an In-Line-Suction Tissue Collector From Byproducts of Anterior Cruciate Ligament Reconstruction Surgery

Purpose

To investigate the viability of cells collected with an in-line-suction autologous tissue collector from the tissue byproducts of arthroscopic anterior cruciate ligament (ACL) reconstruction, to characterize cells from different tissue types, and to identify mesenchymal stem cells.

Methods

Patients aged 14 to 50 years with ACL injuries requiring arthroscopic reconstruction surgery were offered enrollment and screened for participation. In total, 12 patients were enrolled in the descriptive laboratory study. Arthroscopic byproduct tissue was collected with an in-line-suction autologous tissue collector from 4 intraoperative collection sites for each patient: ACL stump, ACL fat pad, notchplasty debris, and tunnel drilling debris. All tissue samples were digested using collagenase, and the derived cellular populations were analyzed in vitro, characterizing cellular viability, proliferative potential, qualitative multipotent differentiation capacity, and cell-surface marker presence.

Results

An equivalent mass of arthroscopic byproduct tissue was taken from each of the 4 intraoperative collection sites (1.12-1.61 g, P = .433), which all showed an average viability of at least 99.95% and high average total nucleated cells (≥1.37 × 107 cells/mL). No significant differences in collected mass (P = .433), cellular viability (P = .880), or total nucleated cells (P = .692) were observed between the 4 byproduct tissues. The byproduct tissues did exhibit significant differences in monocyte (P = .037) and red blood cell (P = .038) concentrations, specifically with greater values present in the ACL stump tissue. Cells from all byproduct tissues adhered to plastic cell culture flasks. Significant differences were found between colony-forming unit fibroblast counts of the 4 byproduct tissues when plated at 106 (P = .003) and 103 (P = .016) cells as the initial seeding density. There was a significant relationship found between both the starting concentration (χ2 = 32.7, P < .001) and the byproduct tissue type (χ2 = 30.4, P < .001) to the presence of ≥80% confluency status at 10 days. Cells obtained from all 4 byproduct tissues qualitatively showed positive tri-lineage (adipocyte, osteoblast, chondroblast) differentiation potential compared with negative controls under standardized in vitro differentiation conditions. Cells derived from all 4 byproduct tissues expressed cell-surface antigens CD105+, CD73+, CD90+, CD45-, CD14-, and CD19- (>75%), and did not express CD45 (<10%). There were no statistically significant differences in cell-surface antigens between the four byproduct tissues.

Conclusions

This descriptive laboratory study demonstrated that cells derived from arthroscopic byproduct tissues of ACL reconstruction remain viable when collected with an in-line-suction autologous tissue collector and these cells meet the ISCT criteria to qualify as mesenchymal stem cells.

Clinical Relevance

It is known that viable mesenchymal stem cells reside in byproduct tissue of anterior cruciate ligament reconstruction surgery (ACLR). Practical methods to harvest these cells at the point of care require further development. This study validates the use of an in-line-suction autologous tissue collector for the harvest of viable mesenchymal stem cells after ACLR.

Augmentation of ACL Autograft Reconstruction With an Amnion Collagen Matrix Wrap and Bone Marrow Aspirate Concentrate: A Pilot Randomized Controlled Trial With 2-Year Follow-up

Background

It is theorized that the lack of a synovial lining after anterior cruciate ligament (ACL) injury and ACL reconstruction (ACLR) contributes to slow ligamentization and possible graft failure. Whether graft maturation and incorporation can be improved with the use of a scaffold requires investigation.

Purpose

To evaluate the safety and efficacy of wrapping an ACL autograft with an amnion collagen matrix and injecting bone marrow aspirate concentrate (BMAC), quantify the cellular content of the BMAC samples, and assess 2-year postoperative patient-reported outcomes.

Study Design

Randomized controlled trial; Level of evidence, 2.

Methods

A total of 40 patients aged 18 to 35 years who were scheduled to undergo ACLR were enrolled in a prospective single-blinded randomized controlled trial with 2 arms based on graft type: bone-patellar tendon-bone (BTB; n = 20) or hamstring (HS; n = 20). Participants in each arm were randomized into a control group who underwent standard ACLR or an intervention group who had their grafts wrapped with an amnion collagen matrix during graft preparation, after which BMAC was injected under the wrap layers after implantation. Postoperative magnetic resonance imaging (MRI) mapping/processing yielded mean T2* relaxation time and graft volume values at 3, 6, 9, and 12 months. Participants completed the Single Assessment Numeric Evaluation Score, Knee injury and Osteoarthritis Outcome Score, and pain visual analog scale. Statistical linear mixed-effects models were used to quantify the effects over time and the differences between the control and intervention groups. Adverse events were also recorded.

Results

No significant differences were found at any time point between the intervention and control groups for BTB T2* (95% CI, -1.89 to 0.63; P = .31), BTB graft volume (95% CI, -606 to 876.1; P = .71), HS T2* (95% CI, -2.17 to 0.39; P = .162), or HS graft volume (95% CI, -11,141.1 to 351.5; P = .28). No significant differences were observed between the intervention and control groups of either graft type on any patient-reported outcome measure. No adverse events were reported after a 2-year follow-up.

Conclusion

In this pilot study, wrapping a graft with an amnion collagen matrix and injecting BMAC appeared safe. MRI T2* values and graft volume of the augmented ACL graft were not significantly different from that of controls, suggesting that the intervention did not result in improved graft maturation.

Registration

NCT03294759 (ClinicalTrials.gov identifier).

Shoulder Range of Motion Deficits in Youth Throwers Presenting With Elbow Pain

BACKGROUND

Glenohumeral internal rotation deficit (GIRD) and total arc of motion difference (TAMD) have been associated with elbow injuries in throwing athletes.

HYPOTHESIS

Youth pitchers with elbow pain will have greater GIRD and TAMD compared with youth pitchers without elbow pain.

STUDY DESIGN

Cross-sectional study.

LEVEL OF EVIDENCE

Level 3.

METHODS

Glenohumeral range of motion of 25 consecutive throwing athletes presenting with elbow pain and that of a matched control group of 18 asymptomatic throwing athletes were compared. Bilateral glenohumeral internal rotation, external rotation, and horizontal adduction at 90° were measured and GIRD and TAMD were then calculated. An analysis of variance was performed to compare range of motion between throwers with and without elbow pain.

RESULTS

The average GIRD of the elbow pain group was 32.7° compared with 14.5° in the control group (P < 0.05). The average TAMD in the elbow pain group was 28.3° compared with 6.7° in the control group (P < 0.05). GIRD and TAMD were present in 88% (22 of 25) and 96% (24 of 25) of the elbow pain group versus 33.3% (6 of 18) and 55.6% (10 of 18) of the control group, respectively.

CONCLUSION

Compared with asymptomatic youth pitchers, those presenting with elbow pain have a statistically significant GIRD and TAMD.

CLINICAL RELEVANCE

This study suggests that a GIRD and TAMD may predispose youth pitchers to present with symptomatic elbow pain.

Medial elbow stability assessment after ultrasound-guided ulnar collateral ligament transection in a cadaveric model: ultrasound versus stress radiography

BACKGROUND

The ulnar collateral ligament (UCL), consisting of 3 bundles, is the primary medial restraint in the elbow. Recent research has demonstrated that ultrasound is an effective modality to evaluate the medial elbow, whereas stress radiography is standard practice in the measurement of medial elbow laxity. This study (1) compared dynamic ultrasound (US_D) with stress radiography in the evaluation of UCL insufficiency and (2) further evaluated the contribution of the anterior bundle of the UCL to medial elbow stability.

METHODS

Stress radiographs and US_D were used to obtain coronal plane measurements of the medial joint space of 16 cadaveric elbows before and after US_D-guided isolated transection of the anterior bundle of the UCL. Measurements were performed with and without a valgus stress applied to the elbows, and gapping of the ulnohumeral joint space was documented.

RESULTS

Transection of the anterior bundle of the UCL resulted in 1.5 mm and 1.7 mm of additional gapping in the ulnohumeral joint as measured with stress radiographs and US_D, respectively. No differences were recorded in the ulnohumeral gapping measurements between stress radiography and US_D.

CONCLUSIONS

The lack of difference between measurements reveals US_D is as reliable as stress radiography in evaluating the medial ulnohumeral joint space and continuity of the UCL while eliminating radiation exposure and minimizing cost of the diagnostic examination. The increase in ulnohumeral gapping with isolated transection of the anterior bundle of the UCL demonstrates its significant contribution to medial elbow stability.

Return to Play and Outcomes in Baseball Players After Superior Labral Anterior-Posterior Repairs

BACKGROUND

Few studies have documented the outcomes of superior labral anterior-posterior (SLAP) repairs in baseball players. Furthermore, the results of these previous studies varied widely and were based on small numbers of patients. Hypothesis/Purpose: The purpose was to report return-to-play (RTP) rates and validated subjective outcome scores for baseball players after SLAP repair. It was hypothesized that RTP rates and outcomes would be significantly different between pitchers and nonpitchers, as well as among baseball levels.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

A series of 216 baseball players was identified who had isolated SLAP repair or SLAP repair with debridement of partial-thickness (<25%) rotator cuff tear at our surgical centers. Patients were contacted by phone a minimum of 2 years after surgery and asked questions about their ability to RTP. Patients were also asked questions to complete the Western Ontario Shoulder Instability Index (WOSI), Veteran's RAND 12-Item Health Survey (VR-12), and Kerlan-Jobe Orthopaedic Clinic (KJOC) questionnaires. Statistical equivalence in RTP rate, VR-12, and WOSI scores was determined between players with and without concomitant rotator cuff debridement using 2 one-sided tests and risk difference measures. Differences in RTP were tested among baseball levels (high school, college, professional) and positions (pitcher vs nonpitcher) using chi-square analyses ( P < .05). Differences in outcomes scores were compared using t tests and analyses of variance ( P < .05).

RESULTS

Of the 216 baseball players, 133 were reached by phone for follow-up interview (mean, 78 months; range, 27-146 months). Overall, 62% successfully returned to play. There were no differences in RTP rates or subjective outcomes among baseball levels or between procedures. RTP rates were 59% for pitchers and 76% for nonpitchers ( P = .060). Subjectively, the percentage of patients who felt the same or better at follow-up compared to preinjury was significantly higher among nonpitchers (66%) than pitchers (43%). There was no difference in KJOC scores between the pitchers (75.3 ± 19.4) and nonpitchers (76.2 ± 17.4) who successfully returned to play, although these scores were well below the minimum desired score of 90 for healthy baseball players.

CONCLUSION

SLAP repair should continue to be considered as an option for SLAP tear treatment only after nonsurgical management has failed. Some players may be able to return to baseball after SLAP repair, although regaining preinjury health and performance is challenging.

Biomechanical Comparison of Fixed-Loop and Adjustable-Loop Cortical Suspensory Devices for Metaphyseal Femoral-Sided Soft Tissue Graft Fixation in Anatomic Anterior Cruciate Ligament Reconstruction Using a Porcine Model

PURPOSE

To compare the displacement, stiffness, and ultimate failure load of a fixed-loop cortical suspensory device with 2 adjustable-loop devices when positioned on metaphyseal bone.

METHODS

Thirty devices (10 of each device) were positioned on the metaphyseal cortex of 30 porcine femora simulating anatomic anterior cruciate ligament femoral tunnel placement. Bovine tendons were used for soft tissue grafts, and the constructs were then cycled 1,000 times and pulled to failure, measuring displacement, stiffness, and failure load.

RESULTS

Initial displacement, cyclic displacement, and total displacement were 2.98 mm, 2.09 mm, and 5.08 mm for the Endobutton CL (ECL), 2.82 mm, 2.27 mm, and 5.09 mm for the Tightrope (TRT), and 4.25 mm, 3.19 mm, and 7.44 mm for the adjustable-loop ToggleLoc Inline with Ziploop (TLZ), respectively. There was no difference between the ECL and the TRT on any measured outcome. Differences between the TLZ and ECL were statistically significant (initial displacement P = .024, cyclic displacement P < .001, and total displacement P < .001), as were those between the TLZ and TRT (initial displacement P = .010, cyclic displacement P = .001, and total displacement P < .001). Failure loads were 804 N, 801 N, and 682 N for the TRT, ECL, and TLZ, respectively, with no statistically significant difference.

CONCLUSIONS

When positioned on the metaphyseal cortex, there was no difference in the biomechanical performance of the fixed-loop ECL and adjustable-loop TRT, and no lengthening of the TRTs was observed during cycling. However, the TLZ showed statistically significantly lower stiffness and more displacement during cycling with lengthening of the adjustable loop, the clinical significance of which is unknown.

CLINICAL RELEVANCE

When used for femoral-sided soft tissue graft fixation in an anatomically placed femoral tunnel, the adjustable-loop TRT was biomechanically equivalent to the fixed-loop ECL. However, the adjustable-loop TLZ showed displacement during biomechanical testing that could potentially contribute to clinical failure after anterior cruciate ligament reconstruction. However, the clinical significance was not directly tested.

Outcomes After Arthroscopic Bankart Repair in Adolescent Athletes Participating in Collision and Contact Sports

Background:

Literature on arthroscopic stabilization in adolescent patients participating in collision and contact sports is limited, as most studies include adolescents within a larger sample group comprised primarily of adults.

Purpose:

To review the outcomes of arthroscopic Bankart repair for anterior shoulder instability in an adolescent population participating in collision and contact sports.

Study Design:

Case series; Level of evidence, 4.

Methods:

This retrospective review included 39 shoulders in 37 adolescent (≤19 years) athletes who underwent primary arthroscopic Bankart repair using suture anchors with at least 2-year follow-up. All patients had a history of trauma to their shoulder resulting in an anterior dislocation. Outcome measures included patient satisfaction, the visual analog scale (VAS) for pain, American Shoulder and Elbow Surgeons (ASES) score, and Rowe score. Recurrence of dislocation and return to sporting activity were also assessed.

Results:

The mean age at the time of surgery was 16.9 years (range, 15-19 years), and the mean follow-up was 6.3 years (range, 4.3-10.0 years); 58.6% of patients participated in collision sports. Time to surgery after the initial dislocation episode was 9.2 months (range, 0.5-36.2 months). Four shoulders (10.3%) had dislocation events postoperatively. The majority (78.1%) of patients returned to sports at the same level of competition. Mean VAS was 0.49 ± 1.0, and the mean ASES and Rowe scores were 92.8 ± 12.6 and 85.0 ± 24.2, respectively. Univariate analyses demonstrated that subjective functional outcomes were negatively correlated with recurrence (ASES, P = .005; Rowe, P = .001) and failure to return to sport (ASES, P = .016; Rowe, P = .004). Independent variables shown to have no significant relationship to functional outcomes included age, follow-up, number of preoperative dislocations, time to surgery, sport classification, competition level, tear extent, number of anchors, concurrent Hill-Sachs lesion, and repair of a superior labral anterior-posterior (SLAP) lesion.

Conclusion:

Arthroscopic Bankart repair is an effective surgical option for traumatic shoulder instability in adolescents participating in collision and contact sports. At a minimum 4-year follow-up, arthroscopic Bankart repair effectively restored stability in 90% of cases; 80% returned to their preinjury level of sport.

Ultrasound and Functional Assessment of Transtendinous Repairs of Partial-Thickness Articular-Sided Rotator Cuff Tears

BACKGROUND

Partial-thickness articular-sided rotator cuff tears are a frequent source of shoulder pain. Despite conservative measures, some patients continue to be symptomatic and require surgical management. However, there is some controversy as to which surgical approach results in the best outcomes for grade 3 tears.

HYPOTHESIS/PURPOSE

The purpose of this study was to evaluate repair integrity and the clinical results of patients treated with transtendinous repair of high-grade partial-thickness articular-sided rotator cuff tears. Our hypothesis was that transtendinous repairs would result in reliable healing and acceptable functional outcomes.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Twenty patients with a minimum follow-up of 2 years were included in the study. All patients underwent arthroscopic repair of high-grade partial-thickness rotator cuff tears utilizing a transtendinous technique by a single surgeon. At latest follow-up, the repair integrity was evaluated using ultrasound imaging, and functional scores were calculated.

RESULTS

Ultrasound evaluation demonstrated that 18 of 20 patients had complete healing with a normal-appearing rotator cuff. Two patients had a minor residual partial tear. Sixteen of 20 patients had no pain on visual analog scale. Four patients complained of mild intermittent residual pain. All patients were rated as "excellent" by both the University of California at Los Angeles Shoulder Score and the Simple Shoulder Test.

CONCLUSION

The transtendon technique for the repair of articular-sided high-grade partial rotator cuff tears results in reliable tendon healing and excellent functional outcomes.

Triple-Row Modification of the Suture-Bridge Technique for Arthroscopic Rotator Cuff Repair

Recent advances to improve outcomes in rotator cuff repair include using arthroscopic double-row suture-bridge techniques in an effort to reconstruct the rotator cuff footprint and improve fixation. However, when using this technique for larger tears, it can be difficult to get the lateral portion of the rotator cuff into an anatomic position. This report describes a triple-row modification of the suture-bridge technique that results in significantly more footprint contact area and contact pressure compared with the double-row and standard suture-bridge techniques. Maximizing the rotator cuff footprint contact area exposes more of the tendon to bone and may improve the healing potential.

Outcomes of Bankart Repairs Using Modern Arthroscopic Technique in an Athletic Population

PURPOSE

To report a large number of highly active patients who underwent arthroscopic Bankart repair at our institution over the last decade.

METHODS

A retrospective analysis of patients who underwent primary and revision arthroscopic Bankart repairs using bioabsorbable anchors was performed. Outcome measures included recurrence of dislocation, American Shoulder and Elbow Scores (ASES), Rowe, visual analog scale (VAS), return to sports, and satisfaction scores.

RESULTS

A total of 94 shoulders met the inclusion criteria. The recurrence rate was 6/94 (6.4%) at a mean follow-up of 5 years (range, 3 to 8.3). The mean postoperative scores were as follows: ASES = 91.5/100; Rowe = 84.3/100; VAS = 0.8/10; satisfaction = 8.8/10. In those who attempted to return to sports, 82.5% were able to return to the same level of competition. Statistical analyses revealed a significant increase in risk of recurrence among high school and recreational athletes. No recurrences were observed among professional or college-level athletes. No significant difference in recurrence rates was observed in regards to age, time to surgery, type of athlete (collision v limited contact), repair of SLAP lesion, number of anchors, or revision surgery.

CONCLUSIONS

Although several repair techniques exist for traumatic anterior shoulder instability, arthroscopic repair remains a viable option even in a highly active patient population. This study uniquely identified high school and recreational athletes at higher risk for recurrence. This is perhaps due to inferior shoulder development and technique as well as to limited access to postoperative physical therapy.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

Efficacy of Unloader Bracing in Reducing Symptoms of Knee Osteoarthritis

Braces designed to unload the more diseased compartment of the knee have been used to provide symptomatic relief from osteoarthritis (OA). Research on the efficacy of these braces is needed. Thirty-one patients with knee OA were randomized to receive an unloader brace (n = 16) or not to receive a brace (control group, n = 15). Knee Injury and Osteoarthritis Outcomes Score (KOOS) and visual analog scale (VAS) scores were used to evaluate outcomes. KOOS results showed that the brace group had significantly less pain (P < .001), fewer arthritis symptoms (P = .007), and better ability to engage in activities of daily living (P = .008). There was no difference in function in sport and recreation (P = .402) or in knee-related quality of life (P = .718). VAS results showed that the brace group had significantly less pain throughout the day (P = .021) and had improved activity levels (P = .035). There was no difference in ability to sleep (P = .117) or in use of nonsteroidal anti-inflammatory drugs (P = .138). Our study results showed that use of an unloader brace for medial compartment knee OA led to significant improvements in pain, arthritis symptoms, and ability to engage in activities.

A Biomechanical Comparison of Modified Krackow and Locking Loop Suture Patterns for Soft-Tissue Graft Fixation

PURPOSE

The purpose of this ex vivo biomechanical study was to evaluate the tensile mechanical properties of 2 modified suture-graft constructs regarding elongation after pre-tensioning and cyclic loading as well as load to failure.

METHODS

Thirty fresh-frozen porcine Achilles tendons were randomly divided into 2 groups of 15 specimens to assess elongation of the suture-graft construct across 2 different tendon-grasping techniques: a modified locking SpeedWhip (MLS) stitch and a modified Krackow (MK) stitch. Each tendon was pre-tensioned to 89 N for 10 minutes and then cyclically loaded to 200 N for 200 cycles. Finally, each tendon was loaded to failure.

RESULTS

After being pre-tensioned, the MK group elongated significantly more than the MLS group (7.12 ± 0.95 mm v 6.26 ± 0.94 mm, P = .02). Elongation after cyclic loading for the MK and MLS groups was not significantly different (3.39 ± 0.95 mm and 3.21 ± 0.93 mm, respectively; P > .05). The MK group showed a significantly larger load to failure compared with the MLS group (689 ± 61 N v 604 ± 46 N, P = .000024). The mean tendon cross-sectional area was larger in the MK group (399 ± 5 mm(2)v 393 ± 8 mm(2), P = .02), but this difference did not relate to the amount of elongation or load to failure. All but 1 specimen failed by suture breakage at the square knot.

CONCLUSIONS

The MLS and MK stitches, pre-tensioned to 89 N for 10 minutes, both effectively minimized suture-graft construct elongation after cyclic loading. Consequently, both suture patterns are recommended for soft-tissue graft fixation.

CLINICAL RELEVANCE

The MLS and MK suture configurations may provide sufficient biomechanical fixation of the tendon graft in the clinical setting of soft-tissue fixation without an interference screw.

Evaluation of footprint contact area and pressure using a triple-row modification of the suture-bridge technique for rotator cuff repair

BACKGROUND

Studies suggest that arthroscopic repair techniques may have high recurrence rates for larger rotator cuff tears. A more anatomic repair may improve the success rate when performing arthroscopic rotator cuff repair. We hypothesized that a triple-row modification of the suture-bridge technique for rotator cuff repair would result in significantly more footprint contact area and pressure between the rotator cuff and the humeral tuberosity.

MATERIALS AND METHODS

Eighteen ovine infraspinatus tendons were repaired using 1 of 3 simulated arthroscopic techniques: a double-row repair, the suture-bridge technique, and a triple-row repair. The triple-row repair technique is a modification of the suture-bridge technique that uses an additional reducing anchor between the medial and lateral rows. Six samples were tested per group. Pressure-indicating film was used to measure the footprint contact area and pressure after each repair.

RESULTS

The triple-row repair resulted in significantly more rotator cuff footprint contact area and contact pressure compared with the double-row technique and the standard suture-bridge technique. No statistical difference in contact area or contact pressure was found between the double-row technique and the suture-bridge technique.

CONCLUSION

The triple-row technique for rotator cuff repair results in significantly more footprint contact area and contact pressure compared with the double-row and standard suture-bridge techniques. This more anatomic repair may improve the healing rate when performing arthroscopic rotator cuff repair.

Bilateral os subtibiale and talocalcaneal coalitions in a college soccer player: a case report

An os subtibiale is an accessory bone separated from the distal medial tibia proper. Subtalar tarsal coalition is a failure of joint formation between the talus and calcaneus during hindfoot maturation. The patient in this case report has large bilateral os subtibiale and subtalar coalitions, which were undiagnosed throughout his soccer career until recently when he began having anteriorlateral ankle pain. After failing conservative treatment the patient underwent ankle arthroscopy, which revealed a fully separated, large articular portion of the medial malleolus. The hypertrophic synovium and cartilage were debrided and the patient had a full recovery, returning to soccer 8 weeks after surgery. Os subtibiale is a rare but well-described entity in the radiology and orthopaedic liturature. To our knowledge, bilateral os subtibiale this large has not been described. In addition, an os subtibiale with concomitant subtalar coalition has never been reported. This report will hopefully alert clinicians about these 2 rare anatomic findings and encourage them to use caution when evaluating suspected fractures of the medial malleolus that could be functional os subtibiale ossicles. In addition, we hope to shed some light on the complicated coupling of motion between the ankle and subtalar joint. These may have developed together to allow more normal coupled motion between the ankle and subtalar joint in this high-level college soccer player, and may be relevant to future reports or research in this area.

Anatomy of the anterior bundle of the ulnar collateral ligament

The purpose of this project was to study the anatomy of the anterior bundle of the ulnar collateral ligament and provide anatomic measurements not previously described. Thirteen fresh-frozen cadaver elbows were dissected. A 3-dimensional, electromagnetic, digitizing device was used to measure several anatomic parameters of the anterior bundle of the ulnar collateral ligament. The width of the ligament was not uniform, increasing distally toward the insertion. The average area of the origin was 45.5 mm2, and the average area of the insertion was 127.8 mm2. The edge of the insertion was separated from the ulna articular margin by an average of 2.8 mm. The study provides quantitative data describing the anatomy of the anterior bundle of the ulnar collateral ligament. This information may prove useful in surgical techniques designed to reproduce the anatomy and biomechanics of the elbow after injury.

Efficacy of surgical preparation solutions in foot and ankle surgery

BACKGROUND

Previous studies have demonstrated higher infection rates following orthopaedic procedures on the foot and ankle as compared with procedures involving other areas of the body. Previous studies also have documented the difficulty of eliminating bacteria from the forefoot prior to surgery. The purpose of the present study was to evaluate the efficacy of three different surgical skin-preparation solutions in eliminating potential bacterial pathogens from the foot.

METHODS

A prospective study was undertaken to evaluate 125 consecutive patients undergoing surgery of the foot and ankle. Each lower extremity was prepared with one of three randomly selected solutions: DuraPrep (0.7% iodine and 74% isopropyl alcohol), Techni-Care (3.0% chloroxylenol), or ChloraPrep (2% chlorhexidine gluconate and 70% isopropyl alcohol). After preparation, quantitative culture specimens were obtained from three locations: the hallux nailfold (the hallux site), the web spaces between the second and third and between the fourth and fifth digits (the toe site), and the anterior part of the tibia (the control site).

RESULTS

In the Techni-Care group, bacteria grew on culture of specimens obtained from 95% of the hallux sites, 98% of the toe sites, and 35% of the control sites. In the DuraPrep group, bacteria grew on culture of specimens obtained from 65% of the hallux sites, 45% of the toe sites, and 23% of the control sites. In the ChloraPrep group, bacteria grew on culture of specimens from 30% of the hallux sites, 23% of the toe sites, and 10% of the control sites. ChloraPrep was the most effective agent for eliminating bacteria from the halluces and the toes (p < 0.0001).

CONCLUSIONS

The use of effective preoperative preparation solution is an important step in limiting surgical wound contamination and preventing infection, particularly in foot and ankle surgery. Of the three solutions tested in the present study, the combination of chlorhexidine and alcohol (ChloraPrep) was most effective for eliminating bacteria from the forefoot prior to surgery.

Preincubation of tissue engineered constructs enhances donor cell retention

Cartilage tissue engineering has been the focus of considerable research. However, the fate of transplanted donor cells rarely is explored directly. In the current study, the effect of preincubating perichondrial cells into a polylactic acid scaffold before implantation into an osteochondral defect was studied. The extracellular matrix produced during preincubation was characterized; the viability of the donor cells was assessed; and the retention of the donor cells in the repair tissue was determined using a gene marker on the Y chromosome, the gender-determining region Y gene. During in vitro incubation, the cells produced an extracellular matrix consisting of glycosaminoglycans, and Types I and II collagen, and the cell viability remained great. In vivo, preincubated constructs had significantly greater retention of donor cells in the host repair tissue in the short term when compared with nonincubated controls. This study shows the value of preincubating engineered constructs before implantation, and additionally validates the gender-determining region Y gene as an effective tool for assessing the fate of donor cells in cartilage tissue engineering.

Bacterial skin contamination after surgical preparation in foot and ankle surgery

An effective presurgical preparation is an important step in limiting surgical wound contamination and preventing infection. The purpose of this study was to evaluate residual bacterial skin contamination after surgical skin preparation in foot and ankle surgery to determine if current techniques are satisfactory in eliminating harmful pathogens. Fifty consecutive patients having surgical procedures of the foot and ankle were studied. Each lower extremity was prepared randomly with either a one-step povidone-iodine topical gel or a two-step iodophor scrub followed by a povidone-iodine paint. After preparation and draping, cultures were obtained at three locations: the hallux nailfold, web space between the second and third, and fourth and fifth toes, and the anterior ankle (control). In the gel group, positive cultures were obtained from 76% of halluces, 68% of toes, and 16% of controls. In the scrub and paint group, positive cultures were obtained from 84% of halluces, 76% of toes, and 28% of controls. Numerous pathogens were cultured, with Staphylococcus epidermidis being the most prevalent. Based on the findings of the current study, presurgical skin preparation with a povidone-iodine based topical bactericidal agent is not sufficient in eliminating pathogens in foot and ankle surgery. The unique environment of the foot and its resident organisms may play a role in the higher infection rates associated with surgery of the foot and ankle.

Donor cell fate in tissue engineering for articular cartilage repair

Articular cartilage repair is a clinical challenge because of its limited intrinsic healing potential. Considerable research has focused on tissue engineering and transplantation of viable chondrogenic cells to enhance cartilage regeneration. However, the question remains: do transplanted allogenic cells survive in the repair with time? This study assessed donor cell fate after transplantation of male New Zealand White rabbit perichondrium cell and polylactic acid constructs into osteochondral defects created in the medial femoral condyles of female New Zealand White rabbits. Repair tissue was harvested at 0, 1, 2, 3, 7, and 28 days after implantation and was evaluated for cell viability and total cell number using confocal microscopic analysis. The number of donor cells in each sample was estimated using quantitative polymerase chain reaction targeting a gender-specific gene present on the Y-chromosome, the sex-determining region Y gene, and a control deoxyribonucleic acid present in male and female cell deoxyribonucleic acid, the matrix metalloproteinase-1 gene promoter. Average cell viability was found to be 87% or more at all times. Donor cells were present in repair tissue for 28 days after implantation. However, the number of donor cells declined from approximately 1 million at Time 0 to approximately 140,000 at 28 days. This decline in donor cells was accompanied by a significant influx of host cells into the repair tissue. This study shows that the sex-determining region Y gene is a valuable marker for tracking the fate of transplanted allogenic cells in tissue engineering.