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PubMed2006

Midterm results of meniscal repair using the BioStinger meniscal repair device.

PURPOSE: The purpose of this study was to evaluate the midterm healing rate and any adverse events from meniscus repair using the BioStinger meniscus repair device (Linvatec, Largo, FL). METHODS: A retrospective review of a consecutive series of meniscal repairs performed by a single surgeon using the BioStinger was conducted. The BioStinger is cannulated, made of molded poly L-lactic acid, and inserted over a needle into the meniscus tissue. Clinical results and adverse events were noted, and Lysholm, Tegner, Cincinnati, and International Knee Documentation Committee (IKDC) activity scores were obtained on all patients. RESULTS: Forty-one patients underwent 41 meniscal repairs with an average follow-up of 38.6 months (range, 24 to 69 months); 35 meniscus repairs were performed in conjunction with anterior cruciate ligament reconstruction and 6 in stable knees. Tears repaired were peripheral, posterior horn tears with an average length of 2 cm. Clinical evidence of meniscal healing was observed in 95% at the time of last follow-up. Six second-look arthroscopies were performed and 2 failures were found. All other patients were symptom free. At follow-up, the mean Tegner score was 6.1 (2.8 preoperative), IKDC activity score was 3.3 (2.1 preoperative), Lysholm score was 90.6 (48.7 preoperative), and the mean Cincinnati score was 86.7 (41.3 preoperative). Four patients had peripheral migration of the device without skin tenting or perforation; 3 underwent removal of the BioStinger from the soft tissues and the other resolved after 12 months. CONCLUSIONS: The midterm clinical success rate was 95% using the BioStinger device. Adverse events were observed in few cases. LEVEL OF EVIDENCE: Level IV, cases series.

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PubMed2005

Suture strength and angle of load application in a suture anchor eyelet.

PURPOSE: To assess the effect of suture material, anchor orientation, and anchor eyelet design on the static loading properties of suture anchors. TYPE OF STUDY: Biomechanical bench study. METHODS: Two metallic suture anchors, Mitek GII (Mitek, Westwood, MA) and Corkscrew (Arthrex, Naples, FL) and a bioabsorbable anchor (Biocorkscrew; Arthrex) were tested with single strand of No. 2 Ethibond (Ethicon, Norderstedt, Germany) or No. 2 FiberWire (Arthrex) suture. Suture pull angle was varied through 0 degrees, 45 degrees, and 90 degrees with the anchor rotation angle in either a sagittal or coronal plane. Constructs were tested to failure using an MTS 858 Bionix testing machine (Material Testing Systems, Eden Prairie, MN). Peak loads, stiffness, energy to peak load, and failure modes were determined for all samples. RESULTS: FiberWire showed superior static mechanical properties when compared with single-strand Ethibond over all testing conditions (P < .05). Suture pull angle had a significant effect on load to failure with both metallic anchors but not on the bioabsorbable anchor (P < .05). CONCLUSIONS: Suture pull angle and anchor rotation angle play an important role in the failure load of suture when placed in an eyelet. The polyaxial nature of the Biocorkscrew eyelet allows for increased degrees of freedom but introduces failure of the suture eyelet as a new failure mode. CLINICAL RELEVANCE: The loading direction and placement of the suture anchor plays a role in the performance of the suture anchor-suture complex.

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PubMed2005

A biomechanical comparison of Bosworth and poly-L lactic acid bioabsorbable screws for treatment of acromioclavicular separations.

PURPOSE: The purpose of this study was to determine the failure load of intact coracoclavicular ligaments and the pullout strength of a poly-L lactic acid screw (PLLA, Linvatec, Largo, FL) compared with a titanium screw (Bosworth, Stryker Howmedica Osteonics, Allendale, NJ) in the repair of fifth-degree acromioclavicular separations. TYPE OF STUDY: Biomechanical cadaveric study. METHODS: The ultimate tensile strength of coracoclavicular ligaments was determined using a servohydraulic testing machine (MTS, Eden Prairie, MN) by creating grade V acromioclavicular separations. Titanium Bosworth screws and Linvatec PLLA screws were placed across the reduced coracoclavicular joint and through the base of the coracoid process of right and left matched cadaveric shoulder specimens, respectively. The axial pullout strength was determined by MTS uniaxial tensile testing along the screw axis to determine the ultimate fixation failure load at a rate of 1 mm/second. RESULTS: Intact coracoclavicular ligaments required an axial load of 340.15 +/- 100.77 N to fail. The bioabsorbable PLLA screw provided fixation strength that was significantly less than the Bosworth screw fixation strength: 272.01 +/- 63.26 and 367.01 +/- 111.54 N, respectively (P < .05, paired t test). CONCLUSIONS: The titanium Bosworth screw restored strength to the acromioclavicular joint equivalent to the intact coracoclavicular ligament; however, the bioabsorbable PLLA screw fixation was significantly weaker than the intact ligaments and the Bosworth repair. CLINICAL RELEVANCE: Titanium Bosworth screws supply more strength of fixation in grade V acromioclavicular separations than the PLLA screw tested in this study.

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PubMed2005

Arthroscopic repair of full-thickness rotator cuff tears using bioabsorbable tacks.

PURPOSE: The purpose of this study was to evaluate the clinical results of bioabsorbable tacks (Suretac; Smith & Nephew Endoscopy, Mansfield, MA) for the arthroscopic repair of full-thickness rotator cuff tears. TYPE OF STUDY: Prospective case series. METHODS: A prospective clinical review was performed on 53 patients (38 men, 15 women) with full-thickness rotator cuff tears repaired arthroscopically using bioabsorbable tacks. Minimum follow-up was 24 months and patients were evaluated using preoperative and postoperative American Shoulder and Elbow Society (ASES) scores and Short-Form 36 Health Surveys (SF-36). A Constant and Murley score was performed at a minimum of 2 years postoperatively. RESULTS: The average patient age was 51 years (range, 23 to 74 years) and the average time for review was 29 months (range, 24 to 60 months). The average size of rotator cuff tears measured 2.5 cm (range, 1 to 5 cm) and an average of 2 Suretacs (range, 1 to 4) were used for the repair. Ten patients had tears larger than 3 cm and 5 patients had tears that measured 5 cm or larger. The average total score according to the ASES shoulder index improved from 33 to 85 points. The average score for pain improved from 6.9 to 1.3 points. The score for function improved from 11 to 25 points. These results were statistically significant (P < 0.01). There was a significant improvement in all components of the SF-36 survey. The average postoperative Constant score was 87 with the pain component measuring 12 points, range of movement 38 points, and power 21 points. CONCLUSIONS: Arthroscopic repair of full-thickness rotator cuff tears using bioabsorbable tacks produces satisfactory outcomes with regard to objective orthopaedic criteria as well as overall patient satisfaction in terms of pain relief and function. Arthroscopic rotator cuff repairs are technically demanding procedures. The use of tacks facilitates this procedure without any apparent deterioration in clinical results. LEVEL OF EVIDENCE: Level IV, case series.

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PubMed2006

Comparison of initial mechanical properties of 4 hamstring graft femoral fixation systems using nonpermanent hardware for anterior cruciate ligament reconstruction: an in vitro animal study.

PURPOSE: To compare the initial mechanical characteristics of 4 systems used to fix tendons to the femur during anterior cruciate ligament reconstruction. METHODS: A total of 32 porcine femurs were used to study the following fixation systems: Bioabsorbable interference screw (Stryker, Kalamazoo, MI), Bio-Transfix Cross-pin (Arthrex, Naples, FL), Biosteon Cross-pin (Stryker), and a fixation technique based on wrapping the graft around the femoral condyle itself, thus allowing it to be fixed in place without the use of any hardware. The mechanical characteristics of each system were obtained by a preconditioned failure tensile test. RESULTS: The yield load values (990.9 +/- 242.6 N for Bio-Transfix, 905.1 +/- 158.8 N for Biosteon Cross-pin, 684.4 +/- 119.7 N for the without-hardware system (WHS), and 369.4 +/- 120.1 N for the interference screw) revealed significant differences between the techniques that used cross-pins and the other 2 techniques (P < .006) on the one hand, and between the without hardware technique and the interference screw (P < .004) on the other. The stiffness of the 2 cross-pin fixation systems (117.6 +/- 22.5 N for Bio-Transfix and 112.6 +/- 22.5 N for Biosteon) was greater (P < .01) than those of the other systems (79.4 +/- 15.2 N for the WHS and 68.5 +/- 13 N for the interference screw). CONCLUSIONS: The initial biomechanical properties of the 2 cross-pin fixation systems proved to be superior to those of the other 2 systems studied. The WHS fixation system exhibited better mechanical properties than its interference screw counterpart. CLINICAL RELEVANCE: The better initial mechanical characteristics encountered using the Bio-Transfix and Biosteon Cross-pin systems indicate that these systems are better equipped to bear the loads generated by aggressive rehabilitation. The WHS fixation system provides an alternative to interference screw fixation.

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PubMed2006

Arthroscopic double-bundle anterior cruciate ligament reconstruction using autogenous quadriceps tendon.

Recently, the interest in anatomic anterior cruciate ligament (ACL) reconstruction with double-bundle technique has increased so as to reproduce the original load distribution and kinematics of the knee. We developed an arthroscopic double-bundle ACL reconstruction technique using autogenous quadriceps tendon with 2 split grafts and a patellar bone plug. The anteromedial bundle and posterolateral bundle of the ACL are replicated with each split graft of quadriceps tendon and fixed with biodegradable interference screws on the 2 femoral tunnels. The patellar bone plug of the quadriceps tendon is fixed with a biodegradable interference screw within the 1 tibial tunnel. We suggest that our technique using quadriceps tendon may be an alternative in arthroscopic double-bundle ACL reconstruction.

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PubMed2006

Simplified single-portal V-shaped SLAP repair.

We present a simplified and cost-effective method for repair of a type II SLAP lesion that requires only 1 working portal in the rotator interval-the lateral anterosuperior portal (LASP)-which is about 3 cm more lateral than the standard ASP. The rotator cuff tendon or muscle are not violated when using this portal, which provides an unproblematic 30 degrees angle for the drill hole. The biceps root can be firmly reattached anteriorly and posteriorly using 1 double-loaded absorbable bone anchor with a suture eyelet. The first stitch is performed using a straight suture hook to pierce the anterior biceps root from the front. A PDS utility suture helps to shuttle the braided suture in a retrograde manner through the labrum. We then tie a sliding knot seating solidly on top of the labrum. The second stitch is placed with a 45 degrees curved suture hook allowing us to pierce the labrum posteriorly to the biceps from above. Again, a sliding knot will be seated on top of the posterior biceps root, pressing it firmly onto the previously abraded bone. The completed repair looks like a V and produces secure fixation of the biceps, thus eliminating the peel-back phenomenon.

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PubMed2006

Outcomes of isolated type II SLAP lesions treated with arthroscopic fixation using a bioabsorbable tack.

PURPOSE: The objective was to clinically evaluate the treatment of type II Slap lesions repaired surgically using a bioabsorbable device. TYPE OF STUDY: Retrospective clinical follow-up study. METHODS: Forty-one patients with isolated type II SLAP lesions who were treated with arthroscopic fixation were identified. Patients were excluded for rotator cuff tears, instability, or subacromial decompression. Patients completed the L'Insalata and the American Society of Shoulder and Elbow Surgeons (ASES) questionnaires, and underwent a thorough shoulder examination at a minimum of 2 years postoperatively. RESULTS: At a mean of 3.7 years follow-up, 33 of 41 patients returned for physical examination and 6 others returned the L'Insalata questionnaire. The mean L'Insalata and ASES scores were 86.7 and 86.8, respectively; 27 patients reported their satisfaction as good to excellent but only 14 of the 29 athletes returned to their preinjury level of athletics. The average ASES scores were statistically different in patients who had their rotator cuff pierced versus those who did not (P< .05). In addition, 13 of 16 patients who experienced night pain had a cuff piercing approach. CONCLUSIONS: Despite high outcome scores, overall patient satisfaction was only 71%. In addition, up to 41% continued to experience some degree of night pain. Patients treated with a rotator cuff piercing had a significantly poorer outcome. Moreover, the patients who were athletes performed poorer on their outcomes evaluation than did their nonathletic counterparts. Whereas the outcome scores overall were high, this problem is still difficult to treat successfully. This may be because of the high demands of athletes. The data also suggest that placing portals through the rotator cuff may be associated with poorer surgical outcomes. LEVEL OF EVIDENCE: Level III.

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PubMed2006

Arthroscopically assisted reduction of a lateral femoral notch in acute tear of the anterior cruciate ligament.

We report the case of a 20-year-old soccer player who suffered a tear of the anterior cruciate ligament with a depression fracture of the lateral femoral condyle. In addition to repairing the ligament we were able to arthroscopically reduce the depression fracture using a bioabsorbable screw. We tamped the surrounding cancellous bone with dilatators and chisels to create a bearing for an interference screw. This prepared for the placing of the screw and resulted in a sufficient reshaping of the condyle. We then inserted a threaded bioabsorbable interference screw into the lateral condyle under arthroscopic guidance to reline the fracture and reduce joint incongruity. Postoperative magnetic resonance imaging showed a significant reduction of the fracture.

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PubMed2006

Meniscal repair for anterior horn tear of the lateral meniscus.

This technical note describes all-inside meniscal repair for anterior horn tears of the lateral meniscus. A modified anteromedial portal is created for use in visualizing the anterior horn of the lateral meniscus. A crescent-shaped suture hook loaded with a polydioxanone suture (PDS) is inserted through an anterolateral portal. The hook tip penetrates the meniscal peripheral rim and advances across the tear. The suture hook penetrates the mobile central fragment. A leading limb of the PDS is advanced into the knee joint. Then, the leading limb of the suture is retrieved back to the anterolateral portal. With 2 limbs of PDS, endoscopic knot tying is done. With this simple technique, vertically oriented all-inside meniscal repair of an anterior horn tear of the lateral meniscus with the use of absorbable suture materials is easily performed.

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PubMed2006

Arthroscopic stabilization of superior labral (SLAP) tears with biodegradable tack: outcomes to 2 years.

PURPOSE: This prospective study aimed to document the pain and functional outcomes, over time, of patients whose SLAP lesions had been repaired with biodegradable tacks. METHODS: Superior labral tears were identified in 24 patients from a cohort of 500 patients who had shoulder problems sufficiently disabling to warrant arthroscopic evaluation and management. These labral tears were arthroscopically repaired with 1 to 3 biodegradable tacks (mean, 1.6). Before surgery, all patients completed a questionnaire regarding their shoulder pain and function and were given a systematic clinical examination. To observe their postoperative outcomes over time, the same assessments were made at 2 weeks, 6 weeks, 3 months, 6 months, 1 year, and 2 years after surgery. RESULTS: After labral reattachment, decreases were noted in the patients' mean shoulder pain scores at rest (64% at 3 months), at night (76% at 3 months), and with activity (73% at 6 months). The most significant reductions in mean scores occurred between 6 and 12 weeks (P < .001). Patient-perceived weakness, instability, and stiffness scores also improved from week 6. The ranking of the patients' "overall problem" reduced from an average ranking of "severe" to "mild" by the third preoperative month (P < .001) and was still at this level by the time of their 2-year follow-up appointment. Activity levels for 22 of 24 patients returned to their preinjury levels by 6 months after surgery. CONCLUSIONS: Arthroscopically delivered biodegradable tacks effectively managed superior labral tears and, on average, resulted in a near-complete improvement of pain and recovery of function by 3 months. These good outcomes did not improve further or deteriorate at the 2-year follow-up appointment. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

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PubMed2006

Broken or dislodged poly-L-lactic acid bioabsorbable tacks in patients after SLAP lesion surgery.

PURPOSE: To document the complication of bioabsorbable poly-L-lactic acid (PLLA) tack breakage and repair failure after arthroscopic stabilization of SLAP lesions. METHODS: Six patients (average age, 38 years) were referred to the senior author because of persistent postoperative pain and disability after arthroscopic stabilization of an unstable SLAP lesion was performed with bioabsorbable PLLA tacks. A total of eight tacks were used in the six patients, and the time from index procedure to evaluation at our facility averaged 9.5 months (range, 8 to 12 months). Three patients experienced an identifiable reinjury an average of 4 months after the index procedure was performed. Magnetic resonance imaging (MRI) revealed a broken or dislodged tack in all cases. All patients were taken to the operating room for arthroscopic evaluation of the biceps anchor, tack fragment removal, and restabilization of the SLAP lesion as needed. RESULTS: At repeat arthroscopy, all shoulders were found to have minimal healing of the SLAP lesion with failure of the bioabsorbable tack. Chondral injury was noted in 2 cases. In all cases, revision SLAP repair was performed with the use of arthroscopic suture repair. At an average follow-up of 14 months (range, 8 to 17 months), all patients reported alleviation of symptoms. Five patients had returned to work with no or minimal symptoms. One patient experienced significant improvement in function and range of motion but did not return to work. CONCLUSIONS: Bioabsorbable PLLA tack breakage or dislodgement is a potential postoperative complication after SLAP lesions are arthroscopically stabilized. This event may result in postoperative reports of pain or mechanical symptoms. Surgeons who use these devices must be aware of the potential complications when they evaluate postoperative patients with persistent complaints. MRI may be helpful in identifying tack fragments. Subsequent arthroscopy to evaluate biceps anchor healing, remove tack fragments, and restabilize the labral lesion may be indicated. LEVEL OF EVIDENCE: Level IV, case series.

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PubMed2006

Comparison of in vitro and in vivo complement activation by metal and bioabsorbable screws used in anterior cruciate ligament reconstruction.

PURPOSE: The purpose of the study was to evaluate the biocompatibility of polylactide (PLLA) screws in comparison with standard metal screws for fixation of the patellar tendon graft in human anterior cruciate ligament (ACL) reconstruction. METHODS: A total of 41 patients (22 women and 19 men) were prospectively randomized for the use of metal interference screws (20 patients) or biologically resorbable PLLA screws from Linvatec, Largo, FL (21 patients). Average age at the time of surgery was 26 years (15 to 51 y). Synovial fluid and plasma were collected preoperatively and after 6 weeks in both groups. Plasma was analyzed for C5a and synovial fluid, as well as for terminal SC5b-9 complement complex (TCC) and interleukin (IL)-8. At 1 year after surgery, serum was incubated with metal, PLLA, and no screws; this was followed by analysis of C5a after 1 and 6 hours of incubation. Inflammatory mediators were measured through enzyme-linked immunosorbent assay (ELISA). RESULTS: In the BioScrew group, 4 patient samples showed high C5a concentration in synovial fluid after 6 weeks, but no statistically significant difference was observed between the 2 groups (P = .11). One patient in the BioScrew group had a high TCC value after 6 weeks, but no statistically significant difference was seen between the 2 groups (P = .20). In the in vitro study, no increased C5a generation was observed in sera incubated with a BioScrew or a metal screw compared with controls. CONCLUSIONS: No statistically significant difference was observed between the BioScrew and metal screw groups concerning C5a, TCC, and IL-8 formation. However, some patients in the BioScrew group showed elevated values. LEVEL OF EVIDENCE: Level II, prospective randomized trial.

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PubMed2006

Arthroscopic stabilization of the shoulder: a prospective randomized study of absorbable versus nonabsorbable suture anchors.

PURPOSE: The aim of this study was to evaluate, prospectively, outcomes following arthroscopic Bankart repair performed with 2 types of suture anchor--the G II (DePuy Mitek, Raynham, MA) nonabsorbable anchor and the Panalok (DePuy Mitek) absorbable anchor. METHODS: Patients with a diagnosis of recurrent traumatic anterior instability of the shoulder who were seen in a single unit between April of 2000 and June of 2003 were considered for inclusion in the study. Patients were assessed preoperatively and postoperatively by means of a subjective, patient-related outcome measurement tool (Oxford Instability Score), a visual analogue scale for pain and instability (VAS Pain and VAS Instability), and a quality-of-life questionnaire (Short Form-12 [SF-12]). Length of follow-up was 1.5 to 5 years (mean, 2.6 y). The incidence of recurrent instability and the level of sporting ability were recorded. Patients were randomized to undergo surgical repair with nonabsorbable or absorbable anchors. RESULTS: A total of 130 patients were included in this study, of whom 6 were lost to follow-up; therefore 124 patients (95%) completed the study. Both types of anchor were highly effective. No differences in rate of recurrence or in any of the scores were noted between the 2 groups. In all, 4 patients in the nonabsorbable group and 3 in the absorbable group experienced additional episodes of dislocation after a traumatic event. Rate of redislocation in the whole series was therefore 6%. In addition, 4 patients, all of them from the absorbable group (4%), described ongoing symptoms of instability but no true dislocations. In all, 85% of the patient group have returned to their previous level of sporting activity. CONCLUSIONS: No differences in outcomes of arthroscopic Bankart repair were seen whether absorbable or nonabsorbable anchors were used. Both are highly effective, with a redislocation rate of 6%. LEVEL OF EVIDENCE: Level I, therapeutic randomized controlled trial.

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PubMed2006

Hybrid fixation improves structural properties of a free tendon anterior cruciate ligament reconstruction.

PURPOSE: This study sought to characterize the structural properties of a combined bioabsorbable interference screw and closed loop and button fixation technique (Hybrid) for femoral fixation of a free tendon graft versus a bioabsorbable interference screw or closed loop and button suspension fixation method alone. METHODS: Eighteen porcine femora and quadrupled cadaveric flexor tendons were treated in 3 experimental fixation study groups: (1) closed loop and button suspension (CLBS), (2) bioabsorbable interference screw (BIF), and (3) closed loop and button suspension with supplemental biodegradable interference screw (Hybrid). An Instron testing machine (Instron, Canton, MA) was used to quantify each group's structural properties with cyclic loading and tensile load-to-failure. A video digitizing system measured graft deformation during load-to-failure. RESULTS: The Hybrid fixation group had significantly greater structural properties compared with the CLBS or BIF group. Ultimate loads (mean [SEM] in Newtons) were 1184 (88) N, 813 (83) N, and 561 (62) N for the Hybrid fixation group, CLBS group, and BIF group, respectively. Quasi-steady state cyclic stiffness (mean [SEM] in Newtons per millimeter) was also greatest for the Hybrid fixation group at 165 (11) N/mm, compared with CLBS (122 [8] N/mm), and BIF (95 [9] N/mm). CONCLUSIONS: Femoral free tendon hybrid fixation provides superior structural properties under tensile and cyclic displacement conditions while preserving the working length of the native anterior cruciate ligament. CLINICAL RELEVANCE: Hybrid femoral fixation may minimize postoperative laxity for free tendon anterior cruciate ligament reconstruction.

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PubMed2006

Long-term absorption of poly-L-lactic Acid interference screws.

PURPOSE: To evaluate the long term in vivo degradation of poly-L-lactic acid (PLLA) interference screws with computed tomography (CT) and radiography as used in patellar tendon autograft anterior cruciate ligament (ACL) reconstruction. METHODS: A total of 20 patients who had undergone patellar tendon autograft ACL reconstruction fixed with PLLA screws at least 7 years earlier were evaluated by physical examination, radiography, and CT to determine whether PLLA screw reabsorption and bone ingrowth had occurred. This study was granted Institutional Review Board approval. Lysholm, Tegner, Cincinnati, and International Knee Documentation Committee (IKDC) scores were obtained. CT data were measured in Hounsfield units. RESULTS: In all, 15 men and 5 women were evaluated 104 months after surgery (range, 89 to 124 months). CT and radiography demonstrated that the bone plug had fused to the tunnel wall, and that no intact interference screw was left. A parallel, threaded, and corticated screw tract was visible adjacent to the bone plug. No bone ingrowth had occurred at the screw site, although, occasionally, minimal calcification was seen. This was never as dense as cancellous bone, and no trabeculae were ever present. No positive pivot-shift test results were obtained. Lysholm, Tegner, and Cincinnati scores were 83, 5.6, and 75, respectively, at follow-up. Average KT difference was 0.7 mm. DISCUSSION: PLLA interference screws completely degraded, and the resulting area demonstrated a low Hounsfield count, consistent with soft tissue 7 years after insertion. No significant bone ingrowth occurred at the screw site. Femoral and tibial ACL tunnels were absent of anything but fibrous tissue and usually had a sclerotic cortical lining. CONCLUSION: PLLA biodegradable ACL screws eventually disappear completely. PLLA material is not replaced by bone. ACL graft tunnels are filled with nonossified material. This study provides a baseline for comparison with other biodegradable interference screws that may encourage bone ingrowth as they degrade. LEVEL OF EVIDENCE: Level IV (no or historical control).

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PubMed2006

Prospective evaluation of patellar tendon graft fixation in anterior cruciate ligament reconstruction comparing composite bioabsorbable and allograft interference screws.

PURPOSE: Bioabsorbable interference screws have proved to be biologically safe and to provide adequate graft fixation. Metallic interference screws have therefore been continuously replaced over the years. However, degradation times are highly variable, and bony replacement of the screw does not always occur in human beings. Composite interference screws have recently been introduced to enhance bony integration. We evaluated 2 different composite interference screws and compared them with an allograft interference screw over a 2-year period after anterior cruciate ligament (ACL) reconstruction with an autologous bone-patellar tendon-bone graft. METHODS: Three groups of patients were prospectively evaluated. Poly-L-lactid acid/hydroxyapatite composite screws (BioRCI-HA; Smith & Nephew, Andover, MA) (group A), poly-L-lactid acid/beta-tricalcium phosphate composite screws (Bilok; Atlantech, Radevormwald, Germany) (group B), or allograft interference screws (CorlS; Regeneration Technologies, Alachua, FL) (group C) were used for tibial fixation of a patellar tendon autograft in ACL reconstruction. Each group consisted of 20 patients (mean age, 32.2 +/- 10.9 years in group A, 32.3 +/- 10.6 years in group B, and 31.1 +/- 6.6 years in group C) with no significant (P < .05) differences in age, sex, and time of follow-up. Subjective and clinical International Knee Documentation Committee parameters were evaluated preoperatively and at 3, 12, and 24 months postoperatively; computed tomography scans were obtained postoperatively and at 3, 12, and 24 months; and magnetic resonance imaging (MRI) scans were obtained at 3 and 24 months postoperatively. RESULTS: Screw breakage during insertion occurred in 2 cases (1 in group A and 1 in group B). There was no significant (P < .05) difference in subjective and clinical results at any time of follow-up. No inflammatory response could be detected on MRI in any of the patients in all groups. Computed tomography scans documented complete bone block incorporation at 3 months in all groups. Both composite interference screws showed signs of degradation but were still clearly visible 24 months after ACL reconstruction. At 12 months, a sclerotic rim around the screw cavity could be outlined in group B only. No bony replacement had taken place up to 24 months postoperatively in group A or B. In group C the allograft bone screw was completely integrated and barely visible after 24 months. CONCLUSIONS: All 3 screw types provided adequate graft fixation and were associated with excellent clinical results and no inflammatory response on MRI. Ultimately, a resorbable screw has to be replaced by bone to facilitate revision surgery. Formation of a sclerotic rim around the outline of the screw makes later bony replacement (group B) unlikely. After 24 months, complete bony integration had only taken place when allograft screws were used. CLINICAL RELEVANCE: At 24 months, no advantage of composite screw materials over conventional bioabsorbable screws could be detected. If composite materials will be of any advantage with respect to bony replacement has to be observed with longer-term follow-up. The allograft bone screw was completely incorporated and replaced by cancellous bone after 24 months. Unfortunately, the screw's more complicated handling, higher cost, and limited availability impair the possibilities for its standard clinical use.

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PubMed2006

Aperture fixation in arthroscopic anterior cruciate ligament double-bundle reconstruction.

The native anterior cruciate ligament (ACL) consists of 2 bundles, which have distinct biomechanical yet synergistic functions with respect to anterior tibial translation and combined rotatory loads. Traditionally, most ACL reconstruction techniques have primarily addressed the restoration of the anteromedial bundle, and less consideration was given to the posterolateral bundle. Recently, various ACL double-bundle reconstruction techniques have been described. With most of these techniques, however, an indirect extra-anatomic fixation far from the articular surface was performed. Because extra-anatomic fixation techniques, rather than aperture fixation techniques, are associated with graft tunnel motion, windshield wiper action, and suture stretch-out, concerns may arise regarding delayed biological incorporation, tunnel enlargement, and secondary rotational and anterior instability. We, therefore, present a novel arthroscopic technique that reapproximates the footprints of native ACL with the use of double-strand semitendinosus and gracilis autografts for reconstruction of the anteromedial and posterolateral bundles, respectively. A separate femoral and tibial tunnel is drilled for each double-strand autograft. The femoral tunnel for the anteromedial bundle is drilled primarily through a transtibial technique, and the femoral tunnel for the posterolateral bundle is drilled via an accessory anteromedial portal with the use of a 4-mm offset drill guide in the anteroinferior aspect of the femoral tunnel for the anteromedial bundle. Bioabsorbable interference screws are used in aperture fixation for anatomic fixation of each bundle. This technique attempts to reproduce closely the native ligament and its biomechanical function.

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