Search

Abstract: The aim of the study was to examine whether the peak torque of the hamstring and quadriceps muscles affects the anterior knee laxity measurements in male patients. The study comprised 45 male patients who had a chronic unilateral anterior cruciate ligament (ACL) rupture. Preoperatively, one experienced physiotherapist performed all the KT-1000 examinations. The anterior displacement was registered at 89 Newton. Immediately after the KT-1000 examination, an isokinetic concentric peak torque measurement was performed at 60°/s for both the hamstring and quadriceps muscles. The anterior displacement was significantly larger in the ACL-ruptured knees compared with the noninjured knees (p < 0.001). Patients with strong hamstring muscles on the injured side displayed significantly less knee laxity compared with patients with less strength (p = 0.018). There was an inverse correlation between the peak torque of the hamstring muscles and the KT-1000 anterior laxity measurements in the ACL-ruptured knees (rho = −0.37, p = 0.01). We conclude that male patients with strong hamstring muscles display smaller KT-1000 laxity measurements than patients with less strength.

Abstract: This study included 527 patients (178 female and 349 male) with unilateral anterior cruciate ligament (ACL) rupture who underwent arthroscopic ACL reconstruction using bone-patellar tendon-bone autograft and interference screw fixation. The follow-up examination was performed by independent observers at a median of 38 (21–68) months after the index operation. At the follow-up, the Lysholm score was 86 (14–100) points, the Lysholm instability subscore was 22 (0–25) points and the Lysholm pain subscore was 19 (0–25) points. The Tegner activity level was 6 (1–10). The one-leg-hop test was 91 (0–167)% of the non-injured knee. The difference in the anterior side-to-side laxity as measured with the KT-1000 arthrometer at 89 Newton (N) was 1.5 (–5–13) mm and the total KT-1000 side-to-side difference at 89 N was 2 (–7–11) mm. Using the International Knee Documentation Committee (IKDC) evaluation system, 177 (33.6%) patients were classified as normal (group A), 211 (40%) as nearly normal (group B), 109 (20.7%) as abnormal (group C) and 30 (5.7%) as severely abnormal (group D). The highest correlation coefficients were recorded between the IKDC evaluation system and the Lysholm score (ρ = 0.66), the patients’ subjective evaluation (ρ = 0.53), the Tegner activity level (ρ = 0.34), all the laxity tests (ρ≥ 0.34) and the one-leg-hop test (ρ = 0.28). The resumption of sporting activities and work as evaluated by the Tegner activity level correlated with the patients’ subjective evaluation (ρ = 0.34) but did not correlate with the laxity tests, i.e., the manual Lachman test (ρ = –0.06) and the total and anterior KT-1000 tests (ρ = –0.06). Furthermore, none of the laxity tests correlated with the functional tests or the patients’ subjective evaluation. We conclude that the IKDC evaluation system is a reliable and useful tool for evaluating the post-operative outcome after an ACL reconstruction.

Abstract: The aim of this prospective study was to follow the development of repair tissue in the donor-site area using serial magnetic resonance imaging (MRI) evaluation and to assess whether the MRI findings were correlated with donor-site morbidity. Thirty-seven consecutive patients with unilateral anterior cruciate ligament injuries undergoing elective reconstruction of the ligament were included in the study. They were aged 27 (range 14–50) years. The graft was harvested through two 25-mm vertical incisions with the aim of protecting the infrapatellar nerve and sparing the paratenon. The tendon defect was left open. The patients underwent MRI evaluation at 6 weeks, 6 months and 27 months postoperatively. A final clinical follow-up was made 25 (range 23–29) months postoperatively. MRI demonstrated that the donor-site gap, i.e. the area corresponding to a pathological non-tendinous-like tissue signal, was 9 (range 4–18) mm at 6 weeks, 5 (range 2–14) mm at 6 months and 2 (range 0–5) mm at 27 months. The size of the donor-site gap had significantly decreased at 6 months compared with 6 weeks (P = 0.0001), as well as at 27 months compared with 6 months (P = 0.0001). We conclude that the patellar tendon at the donor site healed gradually, as expressed by a decrease in the area of non-tendinous-like tissue signal on the serial MRI evaluations.

This study included 527 patients (178 female and 349 male) with unilateral anterior cruciate ligament (ACL) rupture who underwent arthroscopic ACL reconstruction using bone-patellar tendon-bone autograft and interference screw fixation. The follow-up examination was performed by independent observers at a median of 38 (21–68) months after the index operation. At the follow-up, the Lysholm score was 86 (14–100) points, the Lysholm instability subscore was 22 (0–25) points and the Lysholm pain subscore was 19 (0–25) points. The Tegner activity level was 6 (1–10). The one-leg-hop test was 91 (0–167)% of the non-injured knee. The difference in the anterior side-to-side laxity as measured with the KT-1000 arthrometer at 89 Newton (N) was 1.5 (–5–13) mm and the total KT-1000 side-to-side difference at 89 N was 2 (–7–11) mm. Using the International Knee Documentation Committee (IKDC) evaluation system, 177 (33.6%) patients were classified as normal (group A), 211 (40%) as nearly normal (group B), 109 (20.7%) as abnormal (group C) and 30 (5.7%) as severely abnormal (group D). The highest correlation coefficients were recorded between the IKDC evaluation system and the Lysholm score (? = 0.66), the patients’ subjective evaluation (? = 0.53), the Tegner activity level (? = 0.34), all the laxity tests (?= 0.34) and the one-leg-hop test (? = 0.28). The resumption of sporting activities and work as evaluated by the Tegner activity level correlated with the patients’ subjective evaluation (? = 0.34) but did not correlate with the laxity tests, i.e., the manual Lachman test (? = –0.06) and the total and anterior KT-1000 tests (? = –0.06). Furthermore, none of the laxity tests correlated with the functional tests or the patients’ subjective evaluation. We conclude that the IKDC evaluation system is a reliable and useful tool for evaluating the post-operative outcome after an ACL reconstruction.

The aim of this prospective study was to follow the development of repair tissue in the donor-site area using serial magnetic resonance imaging (MRI) evaluation and to assess whether the MRI findings were correlated with donor-site morbidity. Thirty-seven consecutive patients with unilateral anterior cruciate ligament injuries undergoing elective reconstruction of the ligament were included in the study. They were aged 27 (range 14–50) years. The graft was harvested through two 25-mm vertical incisions with the aim of protecting the infrapatellar nerve and sparing the paratenon. The tendon defect was left open. The patients underwent MRI evaluation at 6 weeks, 6 months and 27 months postoperatively. A final clinical follow-up was made 25 (range 23–29) months postoperatively. MRI demonstrated that the donor-site gap, i.e. the area corresponding to a pathological non-tendinous-like tissue signal, was 9 (range 4–18) mm at 6 weeks, 5 (range 2–14) mm at 6 months and 2 (range 0–5) mm at 27 months. The size of the donor-site gap had significantly decreased at 6 months compared with 6 weeks (P= 0.0001), as well as at 27 months compared with 6 months (P= 0.0001). We conclude that the patellar tendon at the donor site healed gradually, as expressed by a decrease in the area of non-tendinous-like tissue signal on the serial MRI evaluations.

We describe a novel method to partition recombinant proteins into the polymerrich top phase in poly(ethylene glycol) (PEG)4000/potassium phosphate aqueous two-phase systems. The concept is based on fusion of a gene fragment encoding a short peptide sequence to the product gene of interest thereby changing the partitioning properties of the expressed product protein as a fusion to the peptide. The model protein in this study, ZZ, is a two domain molecule based on staphylococcal protein A (SPA) which distributes evenly in PEG/salt systems. A tetrapeptide sequence, AlaTrpTrpPro (designated the partitioning peptide), was designed by molecular modeling techniques to include exposed tryptophan residues and to have a coding DNA sequence which is possible to polymerize in an obligate head-to-tail fashion at the DNA level. Gene fragments encoding one and three partitioning peptides, respectively, were fused to the 3′ end of the ZZ gene and the fusion proteins were produced intracellularly in Escherichia coli. The partition coefficients of ZZ proteins containing zero, one and three fused partitioning peptides were determined in three PEG 4000/potassium phosphate aqueous two-phase systems of different compositions. In all three phase systems, there were dramatic effects on the partition coefficient by the fused partitioning peptides. In the phase system with the largest effects, the partition coefficient was enhanced from 1.6 to 11.6 by fusing one tetrapeptide sequence to the 147 amino acid model ZZ protein. By the fusion of three partitioning peptides, the coefficient was increased to 96. These results show that fused partitioning peptides have a dramatic effect on the partitioning of a protein in aqueous two-phase systems which may open up new possibilities to utilize aqueous two-phase extraction techniques as a primary recovery step of recombinant proteins.

Abstract: The aim of this study was to compare the clinical and radiographic results in patients with recurrent unidirectional, post-traumatic shoulder instability (dislocations/subluxations). All the patients had a Bankart lesion and underwent reconstruction using either an open or an arthroscopic technique and absorbable implants. Thirty-three consecutive patients (36 shoulders) were operated on by one surgeon. Group A comprised 18 shoulders which underwent an open Bankart reconstruction using absorbable 3.7-mm TAG suture anchors. Group B comprised 18 shoulders which underwent a combination of an intra- and extra-articular arthroscopic stabilization using 8-mm Suretac fixators. The median number of dislocations before the reconstruction was 5 (0–45) in group A and 4 (0–30) in group B (NS). The follow-up examination was performed by an independent observer after a median of 31 (range 25–38) months in group A and 28 (range 18–46) months in group B (NS). An independent radiologist without any knowledge of the surgical procedure evaluated all the radiographs. There were no re-dislocations in either group. In group A, the Rowe and Constant scores were 86 (range 61–98) and 89 (range 73–99), respectively. The corresponding values in group B were 92 (range 83– 98; P = 0.05) and 96 (range 75– 100; NS). The external rotation in abduction was 65� (range 20�–90�) in group A and 83� (range 65�–105�) in group B (P = 0.0017). The radiographs revealed that 10/18 (56%) in group A and 4/18 (23%) in group B had visible drill-holes or cystic formations in conjunction with the drill-holes (P = 0.002). In this study the open procedure resulted in a restriction in external rotation more frequently than the arthroscopic procedure. The radiographs revealed visible drill-holes or cystic formations in conjunction with the drill-holes more frequently when TAG suture anchors were used than when Suretac fixators were used. The radiographic changes did, not appear to affect the clinical outcome, however.

Abstract: The aim of this study was to evaluate the effect of a standard postoperative rehabilitation knee brace on function, stability and postoperative complications at the 2-year follow-up after anterior cruciate ligament (ACL) reconstructive surgery. Seventy-eight consecutive patients with a unilateral chronic ACL rupture reconstructed by the same surgeon using the endoscopic “all-inside” technique, patellar tendon autograft and interference screw fixation were included in the study. The rehabilitation followed a standard protocol. Group A included 39 patients who were supplied postoperatively with a knee brace for 4 (range 3–6) weeks. Group B included 39 patients for whom a brace was not used. The median age was 27 (range 16–48) years in group A and 26 (range 14–51) years in group B. The median time period between the injury and the index operation was 24 (range 3–150) months in group A and 18 (range 3–360) months in group B. All 78 patients were re-examined by two independent observers after a median follow-up period of 25 (range 23–28) months in group A and 24 (range 22– 27) months in group B. The median KT-1000 total side-to-side difference between the reconstructed and the uninjured knees at 89 N was 3 (range –5.5–11) mm in group A and 3 (range –7–10) mm in group B (NS). When the anterior translation was tested separately at 89 N, the corresponding values were 3 (range –4–13) mm in group A and 3 (range –5–10) mm in group B (NS). The median one-leg hop quotient was 95% (range 50%–167%) of the uninjured leg in group A and 92% (range 64%–119%) in group B (NS). The median Lysholm score was 89 (range 39–100) points in group A and 85 (range 37–100) points in group B (NS). In group A, 27/39 (69%) patients and in group B 21/39 (54%) patients were classified as excellent or good (NS). The median Tegner activity level was 7 (range 3–9) in group A and 6 (range 3–9) in group B (NS). Using the IKDC scale, 27/39 (69%) in group A and 24/39 (62%) in group B were classified as normal or nearly normal (NS). The median sick leave in group A was 62 (range 0–357) days and 59 (range 0–243) days in group B (NS). No serious complications occurred during the first 6 postoperative weeks. Two serious complications were, however, registered after the 6th postoperative week. One patient in group A sustained a rupture of the reconstructed ACL 8 weeks postoperatively (3 weeks after removing the brace), and one patient in group B sustained an undislocated patellar fracture during the 7th postoperative week after a fall. This study indicates that the use of a postoperative rehabilitation brace after an arthroscopic ACL reconstruction did not appear to influence either objective stability or subjective function by the 2-year follow-up.

The aim of this study was to compare the clinical and radiographic results in patients with recurrent unidirectional, post-traumatic shoulder instability (dislocations/subluxations). All the patients had a Bankart lesion and underwent reconstruction using either an open or an arthroscopic technique and absorbable implants. Thirty-three consecutive patients (36 shoulders) were operated on by one surgeon. Group A comprised 18 shoulders which underwent an open Bankart reconstruction using absorbable 3.7-mm TAG suture anchors. Group B comprised 18 shoulders which underwent a combination of an intra- and extra-articular arthroscopic stabilization using 8-mm Suretac fixators. The median number of dislocations before the reconstruction was 5 (0–45) in group A and 4 (0–30) in group B (NS). The follow-up examination was performed by an independent observer after a median of 31 (range 25–38) months in group A and 28 (range 18–46) months in group B (NS). An independent radiologist without any knowledge of the surgical procedure evaluated all the radiographs. There were no re-dislocations in either group. In group A, the Rowe and Constant scores were 86 (range 61–98) and 89 (range 73–99), respectively. The corresponding values in group B were 92 (range 83– 98; P= 0.05) and 96 (range 75– 100; NS). The external rotation in abduction was 65° (range 20°–90°) in group A and 83° (range 65°–105°) in group B (P= 0.0017). The radiographs revealed that 10/18 (56%) in group A and 4/18 (23%) in group B had visible drill-holes or cystic formations in conjunction with the drill-holes (P= 0.002). In this study the open procedure resulted in a restriction in external rotation more frequently than the arthroscopic procedure. The radiographs revealed visible drill-holes or cystic formations in conjunction with the drill-holes more frequently when TAG suture anchors were used than when Suretac fixators were used. The radiographic changes did, not appear to affect the clinical outcome, however.

The aim of this study was to evaluate the effect of a standard postoperative rehabilitation knee brace on function, stability and postoperative complications at the 2-year follow-up after anterior cruciate ligament (ACL) reconstructive surgery. Seventy-eight consecutive patients with a unilateral chronic ACL rupture reconstructed by the same surgeon using the endoscopic “all-inside” technique, patellar tendon autograft and interference screw fixation were included in the study. The rehabilitation followed a standard protocol. Group A included 39 patients who were supplied postoperatively with a knee brace for 4 (range 3–6) weeks. Group B included 39 patients for whom a brace was not used. The median age was 27 (range 16–48) years in group A and 26 (range 14–51) years in group B. The median time period between the injury and the index operation was 24 (range 3–150) months in group A and 18 (range 3–360) months in group B. All 78 patients were re-examined by two independent observers after a median follow-up period of 25 (range 23–28) months in group A and 24 (range 22– 27) months in group B. The median KT-1000 total side-to-side difference between the reconstructed and the uninjured knees at 89 N was 3 (range –5.5–11) mm in group A and 3 (range –7–10) mm in group B (NS). When the anterior translation was tested separately at 89 N, the corresponding values were 3 (range –4–13) mm in group A and 3 (range –5–10) mm in group B (NS). The median one-leg hop quotient was 95% (range 50%–167%) of the uninjured leg in group A and 92% (range 64%–119%) in group B (NS). The median Lysholm score was 89 (range 39–100) points in group A and 85 (range 37–100) points in group B (NS). In group A, 27/39 (69%) patients and in group B 21/39 (54%) patients were classified as excellent or good (NS). The median Tegner activity level was 7 (range 3–9) in group A and 6 (range 3–9) in group B (NS). Using the IKDC scale, 27/39 (69%) in group A and 24/39 (62%) in group B were classified as normal or nearly normal (NS). The median sick leave in group A was 62 (range 0–357) days and 59 (range 0–243) days in group B (NS). No serious complications occurred during the first 6 postoperative weeks. Two serious complications were, however, registered after the 6th postoperative week. One patient in group A sustained a rupture of the reconstructed ACL 8 weeks postoperatively (3 weeks after removing the brace), and one patient in group B sustained an undislocated patellar fracture during the 7th postoperative week after a fall. This study indicates that the use of a postoperative rehabilitation brace after an arthroscopic ACL reconstruction did not appear to influence either objective stability or subjective function by the 2-year follow-up.