Predictors of Osteoarthritis Development at a Median 25 Years After Anterior Cruciate Ligament Reconstruction Using a Patellar Tendon Autograft.

BACKGROUND: Few studies have investigated the outcome ≥20 years after an anterior cruciate ligament reconstruction (ACLR) with a bone-patellar tendon-bone autograft, and there is a wide range in the reported rates of radiographic osteoarthritis (OA). PURPOSE: To report on radiographic OA development and to assess risk factors of knee OA at a median 25 years after ACLR with a bone-patellar tendon-bone autograft. STUDY DESIGN: Case-control study; Level of evidence, 3. METHODS: Unilateral ACLRs performed at a single center from 1987 to 1994 were included (N = 235). The study population was followed prospectively with clinical testing and questionnaires. Results from the 3-month, 12-month, and median 25-year follow-up are presented. In addition, a radiographic evaluation was performed at the final follow-up. Radiographic OA was defined as Kellgren-Lawrence grade ≥2 or having undergone ipsilateral knee replacement surgery. Possible predictors of OA development included patient age, sex, time from injury to surgery, use of a Kennedy ligament augmentation device, any concomitant meniscal surgery, and return to preinjury sports after surgery. RESULTS: At long-term follow-up, 60% (141/235) of patients had radiographic OA in the involved knee and 18% (40/227) in the contralateral knee (P < .001). Increased age at surgery, male sex, increased time between injury and surgery, a Kennedy ligament augmentation device, and medial and lateral meniscal surgery were significant predictors of OA development in univariate analyses. Return to preinjury level of sports after surgery was associated with less development of OA. In the multivariate model, medial meniscal surgery and lateral meniscal surgery were independently associated with OA development. The adjusted odds ratio was 1.88 (95% CI, 1.03-3.43; P = .041) for medial meniscal surgery and 1.96 (95% CI, 1.05-3.67; P = .035) for lateral meniscal surgery. Patients who had developed radiographic signs of OA had significantly lower Knee injury and Osteoarthritis Outcome Score and Lysholm scores at long-term follow-up. CONCLUSION: At 25 years after ACLR, 60% of patients had developed OA in the involved knee, and these patients reported significantly lower subjective outcomes. Medial meniscal surgery and lateral meniscal surgery were independent predictors of OA development at long-term follow-up.

Efficacy of treating segmental bone defects through endochondral ossification: 3D printed designs and bone metabolic activities.

Three-dimensional printing (3D printing) is a promising technique for producing scaffolds for bone tissue engineering applications. Porous scaffolds can be printed directly, and the design, shape and porosity can be controlled. 3D synthetic biodegradable polymeric scaffolds intended for in situ bone regeneration must meet stringent criteria, primarily appropriate mechanical properties, good 3D design, adequate biocompatibility and the ability to enhance bone formation. In this study, healing of critical-sized (5 â€‹mm) femur defects of rats was enhanced by implanting two different designs of 3D printed poly(l-lactide-co-ε-caprolactone) (poly(LA-co-CL)) scaffolds seeded with rat bone marrow mesenchymal stem cells (rBMSC), which had been pre-differentiated in vitro into cartilage-forming chondrocytes. Depending on the design, the scaffolds had an interconnected porous structure of 300-500 â€‹µm and porosity of 50-65%. According to a computational simulation, the internal force distribution was consistent with scaffold designs and comparable between the two designs. Moreover, the defects treated with 3D-printed scaffolds seeded with chondrocyte-like cells exhibited significantly increased bone formation up to 15 weeks compared with empty defects. In all experimental animals, bone metabolic activity was monitored by positron emission tomography 1, 3, 5, 7, 11 and 14 weeks after surgery. This demonstrated a time-dependent relationship between scaffold design and metabolic activity. This confirmed that successful regeneration was highly reproducible. The in vitro and in vivo data indicated that the experimental setups had promising outcomes and could facilitate new bone formation through endochondral ossification.

Effect of Early Residual Laxity After Anterior Cruciate Ligament Reconstruction on Long-term Laxity, Graft Failure, Return to Sports, and Subjective Outcome at 25 Years.

BACKGROUND: In spite of supposedly successful surgery, slight residual knee laxity may be found at follow-up evaluations after anterior cruciate ligament reconstruction (ACLR), and its clinical effect is undetermined. PURPOSE: To investigate whether a 3- to 5-mm increase in anterior translation 6 months after ACLR affects the risk of graft failure, rate of return to sports, and long-term outcome. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: From a cohort of 234 soccer, team handball, and basketball players undergoing ACLR using bone-patellar tendon-bone graft, 151 athletes were included who attended 6-month follow-up that included KT-1000 arthrometer measures. A tight graft was defined as <3-mm side-to-side difference between knees (n = 129), a slightly loose graft as 3 to 5 mm (n = 20), and a loose graft as >5 mm (n = 2). Graft failure was defined as ACL revision surgery, >5-mm side-to-side difference, or anterolateral rotational instability 2+ or 3+ at 2-year follow-up. Finally, a 25-year evaluation was performed, including a clinical examination and questionnaires. RESULTS: The rate of return to pivoting sports was 74% among athletes with tight grafts and 70% among those with slightly loose grafts. Also, return to preinjury level of sports was similar between those with slightly loose and tight grafts (40% vs 48%, respectively), but median duration of the sports career was longer among patients with tight grafts: 6 years (range, 1-25 years) vs 2 years (range, 1-15 years) (P = .01). Five slightly loose grafts (28%) and 6 tight grafts (5%) were classified as failures after 2 years (P = .002). Thirty percent (n = 6) of patients with slightly loose grafts and 6% (n = 8) with tight grafts had undergone revision (P = .004) by follow-up (25 years, range, 22-30 years). Anterior translation was still increased among the slightly loose grafts as compared with tight grafts at long-term follow-up (P < .05). In patients with tight grafts, 94% had a Lysholm score ≥84 after 24 months and 58% after 25 years, as opposed to 78% (P = .02) and 33% (P = .048), respectively, among patients with slightly loose grafts. CONCLUSION: A slightly loose graft at 6 months after ACLR increased the risk of later ACL revision surgery and/or graft failure, reduced the length of the athlete's sports career, caused permanent increased anterior laxity, and led to an inferior Lysholm score.

Strength of side-to-side and step-cut repairs in tendon transfers: biomechanical testing of porcine flexor tendons.

The aim of the study was to compare side-to-side with step-cut repairs to determine how much of the width it is possible to remove and still keep the repair strong enough to start active mobilization. Porcine flexor tendons were used to create side-to-side, one-third step-cut and half step-cut repairs. There were 15 repairs in each group. The tensile properties of the constructs were measured in a biomechanical testing machine. All repairs failed by the sutures splitting the tendon longitudinally. The maximum load and stiffness were highest in the side-to-side group. Our findings suggest that the half step-cut repair can withstand the forces exerted during active unrestricted movement of the digits in tendons of this size. The advantage of the step-cut repair is reduced bulkiness and less friction, which might compensate for the difference in strength.

Return to Play and Long-term Participation in Pivoting Sports After Anterior Cruciate Ligament Reconstruction.

BACKGROUND: Rupture of the anterior cruciate ligament (ACL) is a common and feared injury among athletes because of its potential effect on further sports participation. Reported rates of return to pivoting sports after ACL reconstruction (ACLR) vary in the literature, and the long-term consequences of returning have rarely been studied. PURPOSE: To examine the rate and level of return to pivoting sports after ACLR, the duration of sports participation, and long-term consequences of returning to pivoting sports. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: All primary ACLRs with a bone-patellar tendon-bone autograft between 1987 and 1994 (N = 234) in athletes participating in team handball, basketball, or soccer before injury were selected from a single-center quality database. A long-term evaluation (median, 25 years; range, 22-30 years) was performed using a questionnaire focusing on return to pivoting sports, the duration of sports activity after surgery, later contralateral ACL injuries, revision surgery, and knee replacement surgery. Participants were stratified into 2 groups depending on the time between injury and surgery (early, <24 months; late, ≥24 months). RESULTS: A total of 93% of patients (n = 217) responded to the questionnaire. Although 83% of patients returned to pivoting sports after early ACLR, only 53% returned to preinjury level. Similar return-to-sport rates were observed in males and females (P > .05), but males had longer sports careers (median, 10 years; range, 1-23 years) than females (median, 4 years; range, 1-25 years; P < .001). The incidence of contralateral ACL injuries was 28% among athletes who returned to sports versus 4% among athletes who did not return (P = .017) after early ACLR. The pooled reinjury rate after return to preinjury level of sports was 41% (30%, contralateral injuries; 11%, revision surgery). The incidence of contralateral ACL injuries was 32% among females versus 23% among males (P > .05) and, for revision surgery, was 12% among females versus 7% among males (P > .05) after returning to sports. Having a late ACLR was associated with an increased risk of knee replacement surgery (9% vs 3%; P = .049) when compared with having an early ACLR. CONCLUSION: ACLR does not necessarily enable a return to preinjury sports participation. By returning to pivoting sports after ACLR, athletes are also facing a high risk of contralateral ACL injuries. Long-term evaluations in risk assessments after ACLR are important, as a significant number of subsequent ACL injuries occur later than the routine follow-up.

Autologous BPTB ACL Reconstruction Results in Lower Failure Rates Than ACL Repair with and without Synthetic Augmentation at 30 Years of Follow-up: A Prospective Randomized Study.

BACKGROUND: The aim of this study was to compare the 30-year follow-up results after treatment of anterior cruciate ligament (ACL) ruptures with 3 different surgical procedures. METHODS: A total of 150 patients with acute rupture of the ACL who were managed between 1986 and 1988 were randomized into 1 of 3 open repair methods: acute primary repair (n = 49), acute repair with a synthetic ligament augmentation device (LAD) (n = 50), or reconstruction with an autologous bone-patellar tendon-bone (BPTB) graft with retention of the ACL remnants (n = 51). The 30-year follow-up included evaluation of clinical findings, the Tegner and Lysholm questionnaires, radiographic examination, and registration of revisions and knee arthroplasties. RESULTS: A total of 113 patients (75%) were available for the follow-up evaluation; 39 patients were in the primary repair group, 39 in the LAD group, and 35 in the BPTB group. Through telephone calls and investigation of patient medical records, 40 of these patients were excluded from further analyses because of revision surgery, knee arthroplasty in the involved or contralateral knee, or ACL reconstruction in the contralateral knee. One patient in the BPTB group had undergone revision ACL reconstruction compared with 12 in the primary repair group (p = 0.002) and 9 in the LAD group (p = 0.015). Seven patients had undergone knee arthroplasty in the involved knee, with no significant difference among the groups. In the remaining patients, no significant differences were found among the 3 groups with regard to range of motion, laxity, or Tegner and Lysholm scores. Radiographic evidence of osteoarthritis, defined as an Ahlbäck grade of 2 through 5, was found in 42% of the operatively treated knees, with no significant differences among the groups. CONCLUSIONS: In the present 30-year follow-up results of a randomized controlled study, the BPTB graft augmented with the remnants of the ruptured ligament provided superior results with regard to the number of revisions compared with both the primary repair and LAD groups. No significant differences were found with respect to range of motion, laxity, activity, function, radiographic evidence of osteoarthritis, and knee arthroplasties. LEVEL OF EVIDENCE: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Strength of Pulvertaft modifications: tensile testing of porcine flexor tendons.

The aim of the study was to present two new modifications of the Pulvertaft weave, allowing a higher number of weaves without the need for a longer overlap. The mechanical properties were measured and compared with the traditional technique. Forty-five pairs of porcine flexor tendons were randomized to a Pulvertaft repair with three weaves, a Double Pulvertaft and Locking Pulvertaft repairs. In the last two repairs one of the tendons in each repair was split in two before weaving. A difference in the maximum stiffness was observed between the three groups (p = 0.024). All repairs failed by the sutures being sheared through the tendons splitting the tendon fibres longitudinally. The two modifications were both stronger than the Pulvertaft weave and provide an alternative when a strong connection is needed and a longer overlap is impossible.

Performance of bone cements: are current preclinical specifications adequate?

BACKGROUND: Current specifications (standards) for preclinical testing of bone cements (ISO 5833: 2002, ASTM F451-99a) require simple mechanical testing after ageing for 24 h under dry conditions at 23 degrees C. Some bone cements have fulfilled the requirements in the specifications, and yet had inferior clinical results. Clinically, bone cements are subjected to complex loading patterns in a moist or wet environment at 37 degrees C. Thus, both the validity and the robustness of current standard testing protocols can be questioned. METHODS: We examined the influence of temperature and storage medium on the properties of bone cement. We also compared the results of storage and testing under standard conditions of 23 degrees C in dry air, with the results obtained at 37 degrees C in water or plasma. RESULTS: The dry specimens showed an increase in strength and elastic modulus with time, while the values of the wet ones decreased. There was no difference between specimens stored in water or in plasma. Ultimate compressive strength of dry specimens after 24 h was 1.16 times higher than that of the ones stored wet, increasing to 1.34 times after 1 month, and 1.46 times after 6 months (p<0.001 for all comparisons). INTERPRETATION: Testing under dry conditions-as required in current standards-always gave higher values for mechanical properties than did storage and testing under more physiological conditions. The sensitivity of test values to different environments implies that testing conditions for bone cements should be scrutinized in order to develop more relevant testing protocols that reflect the in vivo environment more closely.

Time dependent mechanical properties of bone cement. An in vitro study over one year.

Changes in mechanical properties of bone cements over time are of clinical importance, but not well documented. Specifications for testing do not address the time factor. This study recorded changes in compressive properties and microstructure of one bone cement stored under simulated physiological conditions (water at 37 degrees C) from 20 min up to 1 year and in dry air at 37 degrees C for comparison. Compressive strength increased within the first week (p < 0.001), decreased at 1 month (p < 0.001), and remained at that level at 1 year. Elastic modulus showed a similar development. Maximum strain values, indicating plastic deformability, increased continuously over 1 year. Microscopy revealed microcracks between the pre-polymer beads and the matrix in specimens tested after 20 min, whereas there were less cracks in 1 year specimens. Increase in strength during the first week is due to polymerization and formation of interpenetrating molecular networks. The subsequent decrease could be due to the plasticizing effect of water uptake, as supported by higher values for dry specimens. It can be speculated that microcracks which could be initiated while reducing an arthroplasty at 15 min, acting as initiators for fatigue fractures in the cement mantle, contribute to cement failure. It is recommended that testing of bone cements should be performed after extended ageing at simulated physiological conditions, for the present cement at least 5 weeks. Results obtained at less than one week could be influenced by ongoing polymerization, as well as microcracks and lower coherence between the prepolymer beads and the matrix.

A sixteen-year follow-up of three operative techniques for the treatment of acute ruptures of the anterior cruciate ligament.

BACKGROUND: This study compares three surgical procedures that we used in the past to treat ruptures of the anterior cruciate ligament: acute primary repair, acute repair augmented with a synthetic ligament-augmentation device, and acute repair augmented with autologous bone-patellar tendon-bone graft. METHODS: This is the third report on a group of patients who were randomized to the three different procedures between 1986 and 1988. There were fifty patients in each group. The patients were evaluated prospectively at one, two, five, and sixteen years with use of the Tegner activity score and the Lysholm functional score. Stability of the knee was assessed with clinical examination and with use of the KT-1000 arthrometer. RESULTS: One hundred and twenty-nine (88%) of the 147 patients who were available for follow-up completed the study. Eleven patients (24%) who had a primary repair, four patients (10%) who had repair with a ligament augmentation device, and one patient (2%) who had augmentation with autologous bone-patellar tendon-bone graft underwent anterior cruciate ligament revisions between the primary operation and the sixteen-year follow-up examination. The rate of revision was ten times higher in the group that had primary repair than in the group that had repair with bone-patellar tendon-bone graft (p = 0.003). In the remaining patients, those who had repair with a bone-patellar tendon-bone graft had significantly more stable knees than those who had repair with a ligament augmentation device, as measured by the Lachman test (p = 0.026). Nine (11%) of the eighty-five patients for whom data were available had osteoarthritis in the primarily reconstructed knee, and three patients (3.5%) had osteoarthritis in the contralateral knee at sixteen years (p = 0.001); no difference was noted among the three groups. The mean Lysholm score at sixteen years was 88 points for the knees that had primary repair, 85 points for those that had repair with the ligament augmentation device, and 90 points for those managed with a bone-patellar tendon-bone graft (p = 0.286). CONCLUSIONS: At long-term (sixteen-year) follow-up, the rate of revision anterior cruciate ligament surgery is much higher following primary repair than after primary repair augmented by a bone-patellar tendon-bone graft. It can be expected that approximately 10% of patients undergoing anterior cruciate ligament reconstruction acutely will have osteoarthritis develop in the reconstructed knee. We no longer perform any of these surgical techniques as open procedures.

Should the galvanic combination of titanium and stainless steel surgical implants be avoided?

It is recommended that one should not combine different metals in orthopaedic devices. The least noble metal in such a galvanic coupling is more likely to corrode. However, some studies have failed to show increased corrosion when titanium and stainless steel are combined. The aim of this study was to determine the fretting corrosion of the contact areas between screws and plates made of these dissimilar metals used for internal fixation of bone fractures. The plates were fixed to a bone-simulating material and subjected to tensile and compressive forces in both human serum and Hank's solution. The outcome variables included in the analyses were weight loss, and release of Ti, Cr, Ni and Mo to the different media. Results from the multiple combinations were subjected to multivariate statistics. Principal component analysis visualised our findings and allowed classification of similar samples and separation of discrepant groups of samples. We found a significant effect of the test medium, but no dramatic effect due to mixing of metals. The titanium screws and plates corroded more in serum than in saline, while the opposite was true for stainless steel. Combination of dissimilar screws and plates did not cause higher weight loss or metal release than the single-material constructions, indicating comparable clinical safety.

Are inflatable nails an alternative to interlocked nails in tibial fractures?

Recently developed inflatable nails avoid reaming and interlocking screws in tibial fractures and reflect a new principle for stabilization of long bone fractures. We asked if the bending stiffness, rotational rigidity, or play (looseness of rotation) differed between an inflatable versus large-diameter reamed interlocked nails, and whether the maximal torque to failure of the two bone-implant constructs differed. In a cadaveric model, we compared the biomechanical properties with those of an interlocked nail in eight pairs of fractured tibial bones. Bending stiffness, rotational rigidity, play (looseness in rotation), and torsional strength within 20 degrees rotation were investigated using a biaxial servohydraulic testing system. For all biomechanical variables, we found a large interindividual variance between the pairs attributable to bone quality (osteoporosis) for both fixation methods. The inflatable nail had a higher bending stiffness, with a mean difference of 58 N/mm, and a lower torsional strength, with a mean difference of 13.5 Nm, compared with the locked nail. During torsional testing we noted slippage between the inflatable nail and bone. We observed no differences in play or rotational rigidity. Given the lower torsional strength we recommend caution with weightbearing until there are signs of fracture consolidation.

External fixation versus locked intramedullary nailing in tibial shaft fractures: a prospective, randomised study of 78 patients.

INTRODUCTION: We performed a prospective, randomised study to compare the Ex-fi-re external fixator (EF) with locked intramedullary (IM) nailing in tibial fractures. Only fractures without soft-tissue problems of importance were included. MATERIALS AND METHODS: Ex-fi-re is a unilateral, dynamic axial fixator with fracture reduction capabilities. The Grosse-Kempf nail was used for nailing. A total of 78 patients with 79 fractures were entered in the study (41 Ex-fi-re, 38 IM nails). RESULTS: Time to radiographic union and full weight-bearing did not differ significantly, but unprotected weight-bearing was achieved earlier in the IM group (12 vs 20 weeks; p<0.001). There were more reoperations due to secondary dislocation in the EF group. There were no differences in final angulation or shortening. After 6 months and 1 year there were no differences in knee motion, ankle motion, fracture site pain or ankle pain. Some 64% of the nailed patients complained of anterior knee pain after 1 year. CONCLUSION: The results were comparable in most respects. Unprotected weight-bearing was achieved earlier after IM nailing. Anterior knee pain was frequent after nailing.

Slippage between screwdriver and bone screw.

Cortical 3.5-mm stainless steel screws with hexagonal heads and corresponding screwdrivers from two manufacturers were investigated. Measurement of dimensions and torsional testing were done to study slippage between the screw and the driver bit. There were only small differences in dimensions between the manufacturers. Ultimate torque values obtained were at the level of 2.7 N-m where reaming of the screw socket took place. Additional rotation resulted in approximately (1/2) of the maximum torque. Subsequent torque testing in the opposite direction, corresponding to removal of the screw, revealed that the torque values were equally low in that direction. Additional insertion and removal of bone screws with hexagonal sockets are hampered after only one episode of slippage. It is justified to consider new shapes of drive bits and corresponding screw head sockets, such as a fluted multiedge configuration.

[Removal of osteosynthetic implants]. / Fjerning av osteosyntesemateriale.

BACKGROUND: Removals of fracture implants constitute a considerable share of orthopaedic operations and take up significant hospital resources. In the Norwegian basic fracture course, guidelines are given on indications for removal as well as minimum function time for implants. Indications for implant removal are, however, relative, and we wanted to study actual practice in this field in Norway. MATERIAL AND METHODS: An inquiry was made to Norwegian hospitals in spring 2000 concerning their current practice for implant removal. RESULTS: Most hospitals follow the suggestions given but there is still great variation, especially in age limits for routine removal of all implants, which range from 15 to 70 years. INTERPRETATION: Implant removal is desirable after fracture healing but it requires a surgical procedure with a certain morbidity and incidence of complications. Lack of strict criteria for removal may explain varying practice. We conclude that there should be a uniform practice for implant removal in Norwegian hospitals. More research is warranted on the possible systemic and local long-term effects of implants remaining in situ in order to give more evidence-based indications for implant removal.