Cryo/Cuff use after arthroscopic surgery: effect on knee joint temperature

Any modality that alters joint homeostasis could have a potential negative effect on cartilage. During arthroscopic knee surgery, the temperature in the knee joint decreases significantly. The use of cryotherapy after this surgical procedure could maintain or increase these temperature variations. This prospective, randomized study evaluated the change in intra-articular knee temperature with the use of the Cryo/Cuff (Aircast Inc, Summit, New Jersey) in 30 patients after arthroscopic knee surgery. In 15 patients, a Cryo/Cuff with an automatic pump was applied immediately after surgery (group 1), and in the remaining 15 patients, only a wound dressing was applied (group 2). The mean intra-articular temperature at the beginning of the procedure was 34.8+/-1 degrees C for both groups. At the end of surgery, the temperature was 26.8+/-2.2 degrees C for group 1 and 27.5+/-2.2 degrees C for group 2. One hour after the end of the procedure, the mean temperature was 34+/-1.6 degrees for group 1 and 34.8+/-1.7 degrees C for group 2. These differences were not statistically significant. These results demonstrated that the use of the Cryo/Cuff does not alter temperature recovery in the knee, thereby excluding potential damage to the articular cartilage.

Arthroscopic intra- and extra-articular anterior cruciate ligament reconstruction with gracilis and semitendinosus tendons

Numerous surgical procedures have been developed and used for anterior cruciate ligament (ACL) reconstruction. Patellar tendon is probably the most common graft used, but gracilis and semitendinous tendons present some interesting advantages: small incision, large graft when doubled, characteristics close to ACL, rapid harvest. We describe a combined intra- and extra-articular arthroscopic ACL reconstruction using hamstring tendons which includes some original steps. The tendons are harvested, leaving the distal insertion intact, and sutured together. After drilling of the tibial tunnel, an over-the-top arrangement is formed, creating a groove in the posterolateral aspect of the femur. The tendons are then fixed with double staples in the groove, and their remaining part is fixed distally to Gerdy's tubercle passing under the fascia, but over the lateral collateral ligament (LCL). This technique ensures sufficient strength in the graft and permits correction of any associated instability, because of the presence of the extra-articular portion of the tendons. Furthermore, the over-the-top arrangement reduces trauma and possible pitfalls related to tunnel construction and permits isometry of the extra-articular portion to be established. Forty patients involved in sports activity were prospectively selected and evaluated at a minimum 2 years' follow-up. IKDC score and Lysholm score were used for clinical evaluation, and the KT-2000 was used for instrumental laxity measurements. Resumption of sport and time to that point were recorded as well as Tegner activity score. We had 92.5% normal and fairly normal knees according to IKDC score and only 7.5% abnormal knees. Mean Lysholm score was 95. Mean Tegner score was 7.2. KT-2000 showed a mean injured/uninjured difference of 2.1 mm. In all, 90% of patients resumed sports at the same level, 67.5% in 3-4 months and 27.5% in 4-6 months. The highly satisfactory results of this series with no major complications confirm the reliability of this technique and the possibility of guaranteeing functional behaviour in the knee.

Fiber-based anterior cruciate ligament model for biomechanical simulations

Although accurate predictions of the behavior and function of the anterior cruciate ligament would aid in diagnosis and operative treatment, no agreement exists on the best way to model the ligament with a reliable description of its mechanical and geometric features. We propose a new model of the anterior cruciate ligament based on multiple viscoelastic curvilinear fibers. This model was used for quasi-static simulations of the passive motion of eight porcine knees, after registration of the passive trajectories and digitization of the surface of the ligament in flexion. Simulations of anterior cruciate ligament deformations during passive motion predicted a fiber strain of less than 20%, low insertion forces, and isometric anterior fibers. The model explains actions of the ligament fibers, as reported in the literature, better than classic models based on linear fibers and consistent with the mechanical properties of the anterior cruciate ligament.

pO2 measurement in an experimental model of patellar tendon autograft pro-anterior cruciate ligament

Thirty-four sheep were submitted to surgery substituting the native ACL with the central third of the patellar tendon, ten enter this study. The purpose was to find a possible relationship between tissue pO2 and healing processes considering also the biomechanical and histomorphological aspects of the grafts. Four of them were sacrificed under general anaesthesia after 6 months, and six after 1 year in order to perform tissue pO2 measurement and an analysis of microvessel density on specimens of the normal ACL and the graft. Our data showed higher pO2 values of the autografts after 6 months. After 1 year the data was comparable to those of native ACL. This was confirmed by a microvessel count of the histological specimens and the data was in relationship to biomechanical and histomorphological analysis. Tissue pO2 can be observed and recorded in "in vivo" ACL, and patellar tendon used as graft, with no injury to their integrity. The monitoring system might be considered as an experimental tool for indirect controls of the anterior cruciate substitutes.

Total knee arthroplasty kinematics. Computer simulation and intraoperative evaluation

The goal of this work was to develop computer simulations for intraoperative testing of the passive kinematics of knee prostheses. These are based on an anatomic model of the reconstructed joint, represented in the sagittal plane. A femoral component and a tibial component are linked by 3 springs that model the relevant ligaments, with the posterior cruciate providing the primary constraint. The components' behavior at each flexion angle is obtained by minimizing the total strain energy stored in the ligaments. Simulations were performed in vivo on 10 Interax implants (Howmedica International, Stain, UK) and showed good agreement with intraoperative observations, allowing monitoring of new parameters such as contact point motion, ligament strains, and the energetic state of the knee. This work contributes to the comprehension of individual knee kinematics after total knee arthroplasty, to improve long-term results and standardize the evaluation of the results of joint restoration.

Total knee arthroplasty without patellar resurfacing in active and overweight patients

Overweight patients are often considered poor candidates for total knee arthroplasty (TKA). A retrospective study of this was done on 47 osteoarthritic knees treated by TKA without patella resurfacing between March 1991 and June 1993. The Hospital for Special Surgery (HSS) rating system was used for clinical evaluation, and radiographs to study the degree of osteoarthritis and radiolucency. Correlations between overweight, range of motion (ROM) and stage of patellar damage and other measured variables (HSS score, patellar pain and radiolucency) were studied. Overweight was not correlated with HSS score, radiolucency or patellar pain. ROM was significantly correlated with patellar pain and HSS score, with better results in patients with ROM between 90 degrees and 110 degrees. Therefore, we believe that TKA in osteoarthritic knees can lead to successful results, even in active or overweight patients.

Histological and ultrastructural evaluation of Leeds-Keio ligament six years after implant. A case report

We examined by light and electron microscopy study a Leeds-Keio ligament removed from a patient 6 years and 4 months after implant following rupture. The new ligament presented an outer capsule made up of bundles of collagen fibres running mainly perpendicular to the long axis of the ligament. Septa were seen emerging from the capsule and composed of bundles of collagen fibres surrounding the bundles of Dacron fibres. Each thread of Dacron was surrounded by a layer of connective tissue containing periodic acid-Schiff (PAS)-positive cells. The bundles of collagen fibres making up the outer capsule, the septa and the layer of connective tissue surrounding the Dacron threads were positive for anti-type I collagen antibody. The rehabitated Leeds-Keio ligament presented a specific organization at the septa zone, showing a layer of collagen fibrils alternating with a layer of cells. Our remodelling findings suggest a shoelace effect of the artificial ligament. On the other hand, the presence of type I collagen could be responsible for the good functional behaviour of this composite system. In conclusion, the factors that play an important role in determining this remodelling process and its mechanical function are unknown.

Expression and regulation of glial-cell-line-derived neurotrophic factor (GDNF) mRNA in human astrocytes in vitro

The expression and modulation of mRNA for glial-cell-line-derived neurotrophic factor (GDNF) in human glial cells was investigated. Astrocyte cell cultures were isolated from human fetal brains, characterized by immunocytochemistry and maintained in vitro in conditions of high purity; sister cultures were exposed to protein kinase C (PKC) inhibitors for 20 min. Total RNA was extracted from the cell pellets, reverse-transcribed into cDNA and amplified by the polymerase chain reaction (PCR) with primers specific for GDNF. A reverse-transcription/PCR procedure was also performed on mRNA extracted from human fibroblast and lymphocyte cell lines. Human astrocytes grown in the absence of neurons expressed detectable amounts of mRNA for GDNF but no amplification products were observed in fibroblasts and lymphocytes, thus confirming that GDNF production was cell-type specific. After exposure to PKC inhibitors, a dramatic down-regulation of GDNF mRNA was observed in astrocyte cell cultures. Thus, human astrocytes are constitutively capable of producing GDNF, such trophic activity is restricted to neural cells, and PKC plays key roles in signal pathways that regulate the gene activation and production of GDNF.

Age-related changes in human anterior cruciate ligament (ACL) collagen fibrils

The correlation between anterior cruciate ligament (ACL) collagen fibril diameter and aging were studied in subjects aged 15 to 87 years. The samples processed for light and electron microscopy showed statistically significant differences in collagen fibril diameter among young (< 20 years), adult (20-60) and elderly subjects (> 60 years). In the young, the ACL was made up of collagen fibrils which were highly variable in size (range 20-180 nm); the diameter distribution curve was very asymmetrical (mean asymmetry +0.895). In adults and elderly subjects, the maximum diameter had decreased remarkably (120 and 110 nm, respectively) and the diameter distribution curve had become less asymmetrical (mean asymmetry +0.527 and +0.297 respectively). Fibril concentration increased considerably from young (68 fib/mu 2) and elderly subjects (140 fib/mu 2). This reduction in diameter and the relative change in collagen fibril concentration may be related to changes in elastic stiffness. The increase in small collagen fibrils and the marked rise in their concentration may make the ligament more pliable. These findings are similar to those we obtained in Achilles tendon. They demonstrate that both ACL and Achilles tendon, a tissue which responds to unidirectional mechanical forces more than ACL does, show a reduction in diameter value during ageing. These data further suggest that collagen fibril diameter is related to the aging process.

Arthroscopic management of recurrent anterior dislocation of the shoulder: analysis of technical modifications on the Caspari procedure

Arthroscopic treatment was performed on 71 patients with recurrent shoulder dislocations; all of the patients had monoplanar anterior instability attributable to arthroscopically diagnosed Bankart lesion. Of the 71 operations, 29 were performed using the original Caspari technique (follow-up, 59 months), and 42 were performed after modifications made in the original technique (follow-up, 38 months), notably improved preparation of the capsular reinsertion zone and increase in the number of monofilament points and their anchorage directly to the bone, on the spine of the scapula. We compared the results obtained in these two differently treated groups, taking into account several factors in the patient's history and clinical condition. These included the number of dislocation episodes before the operation, as well as clinical findings regarding stability, movement, function and pain (Rowe scale score), contralateral shoulder laxity, level of preoperative versus postoperative athletic activity, and postoperative recurrence rate. In the Caspari-treated group, we obtained 66% satisfactory results compared with the 90% obtained in the second group. The recurrence rate was 27% in the first group compared with 4.8% in the second group. These data were statistically significant. No correlation was found between preoperative number of dislocations and recurrence rate, nor for contralateral shoulder laxity. No significant difference was found regarding resumption of sport activity in the two groups. Our data indicate that, with accuracy in patient selection and effective surgical technique, the recurrence rate can be reduced, and results similar to those of the arthrotomic technique may be obtained.

Temperature changes in the knee joint during arthroscopic surgery

Normal joint conditions are altered during arthroscopic surgery, and these changes have uncertain ultrastructural and biomechanical effects on articular cartilage. Experimental studies have shown that temperature variations affect the biomechanical properties of articular cartilage. We documented the temperature of the knee joint in 40 patients at the beginning and end of an arthroscopic procedure (anterior cruciate ligament reconstruction or meniscectomy). The intra-articular measurements were obtained using a digital thermometer connected to a sterile stainless steel probe. Correlation coefficients and linear regression techniques were used to determine which variables are independent predictors of joint temperature at the end of surgery. The mean knee joint temperature before surgery was 35.1 degrees +/- 1.0 degrees C and at the end of surgery 24.6 degrees +/- 1.5 degrees C. The joint temperature at the end of surgery was significantly affected by the temperature of the saline irrigant used and the length of arthroscopic procedure. The clinical implications of our findings must be clarified in animal models.

Arthroscopic reconstruction of the anterior cruciate ligament with Leeds-Keio ligament in non-professional athletes. Results after a minimum 5 years' follow-up

We report our experience using the Leeds-Keio artificial ligament for anterior cruciate ligament (ACL) reconstruction. The study relates the results of the first 40 patients subjected to arthroscopic reconstruction of the ACL with a Leeds-Keio ligament, with a mean follow-up of 73 months. No associated peripheral procedures were carried out on any patient. The average age of the patients at the time of the operation was 31 years (range 26-35 years). The rehabilitation protocol followed by all patients aimed at resumption of sport 4 months after the operation. Clinical assessment included IKDC and the Lysholm scoring scale. The KT-2000 system was used for instrumented evaluation of joint laxity. All patients underwent a radiographic check-up. Clinically there were 55% excellent or good results when using the IKDC scale, while with the Lysholm score, satisfactory results were obtained in 80%. Complete post-traumatic rupture of the ligament was observed in three patients. No patient suffered an episode of either hydrarthrosis or reactive synovitis, which indicates good tolerance to the ligament. The radiographic evaluation of the operated knees showed a close correlation between the appearance of degenerative phenomena and performance of arthroscopic meniscectomy. The results achieved with the Leeds-Keio artificial ligament 5 years after application, although not completely satisfactory and inferior to those obtained with autologous biological ligaments, should be considered an encouragement to promote new efforts in this interesting research field.

Early versus late reconstruction for anterior cruciate ligament rupture. Results after five years of followup

We investigated the clinical and laxity testing results at 5 years' followup in patients who had early or late anterior cruciate ligament reconstruction. Twenty-three patients (Group I) were treated within 15 days of injury. Fifty-nine patients (Group II) were treated more than 3 months after injury. Patellar tendon reconstruction and fascia lata graft augmented with a ligament augmentation device were the techniques used in both groups. According to the International Knee Documentation Committee rating scale, 17 patients in Group I and 38 patients in Group II had satisfactory results. The Lysholm score was good in all Group I patients and in 55 Group II patients. Flexion-extension deficits were comparable for both groups. Eighteen patients (78%) in Group I demonstrated satisfactory results according to the KT-2000 arthrometer testing, compared with 44 (75%) in Group II. No associated lesions were present in 12 (52%) cases in Group I, compared with 26 (44%) cases in Group II. Return to sports at the preoperative level was obtained by 21 (91%) patients in Group I, compared with 42 (71%) in Group II. The patients who had reconstruction during the early phase returned to sports activities sooner and had better clinical and laxity testing results.

Total knee arthroplasty after proximal tibial osteotomy

The cases of ten total knee arthroplasty after a proximal tibial osteotomy were compared with those of 50 primary total knee arthroplasty for osteoarthritis. The groups were matched according to age of patients, length of follow-up and type of prosthesis used. On the basis of HSS, an excellent or good result was obtained in 90% of patients who had had arthroplasty after osteotomy and in 94% of patients after a primary arthroplasty. Though some intraoperative difficulty may be encountered in a secondary prosthesis, osteotomy does not compromise a subsequent arthroplasty.

The preliminary results of press-fit knee arthroplasty without a patellar component

A total of 22 cases of Kinemax prostheses implanted consecutively from January to June 1990 for the treatment of primary gonarthrosis were evaluated; in these cases remodeling of the patella was performed, and the corresponding component of the prosthesis was not used. The mean age of the patients was 64 years, mean follow-up was obtained after 48 months. According to the HSS form results were: excellent: 9 (40.9%); good: 12 (54.5%); fair: 1 (4.6%). The postoperative femorotibial axis measured a mean of 173.8 degrees. There were no complications in the patella, only in 1 case did we observe mild anterior pain. Knee arthroplasty without substitution of the patella seems to guarantee good results in patients with primary gonarthrosis, as long as patellar reconstruction is performed and correct femoropatellar alignment is guaranteed, as well as recovery of the femorotibial axis with accurate positioning of the prosthetic components.

Results in the treatment of recurrent dislocation of the patella after 30 years' follow-up

The authors compare the clinical and radiographic outcome in patients with comparable bilateral recurrent patellar dislocation treated surgically on only one side, to clarify the appropriateness of the surgical indication. Sixteen patients were evaluated at an average follow-up of 30 years (20-45); all had been treated by the Roux technique. The results on both the operated and the unoperated knee were evaluated; the Crosby and Insall schedule was used for the clinical evaluation. Anteroposterior, lateral, and Merchant's view X-rays were examined for osteoarthritis and to measure the height of the patella. The congruence angle and the distance between anterior tibial tuberosity and trochlear groove (ATT-TG) were measured by computed tomography. The results in the operated knees were: 3 excellent, 9 good, 1 fair, and 3 worse; results in the nonoperated knees were 6 excellent, 8 good, 1 fair, and 1 worse. In the operated knees arthritis was grossly marked in 8, marked in 3, moderate in 1, and light in 4; in the nonoperated ones it was grossly marked in 8, moderate in 3, and light in 5. The congruence angle was normal in 10, medially displaced in 3, and laterally displaced in 3 cases on the operated side; on the nonoperated side it was normal in 7 cases and lateralized in the remaining 9. The ATT-TG in the operated knees was negative in 9 cases, normal in 1, and positive in 6; on the non-operated side it was positive or normal. In 7 operated cases a low patella was documented. The Roux technique yields positive results in the correction of recurrent dislocation. No clinical or radiographic differences were found between surgically and conservatively treated knees. The clinical results are generally not comparable with the radiographic features or with severity of degenerative modifications presented at long-term follow-up. The absence of a difference is due basically to the complete lack of adaptation of the surgical procedure to the variable pathogenesis of this disorder.

Comparison between laser meniscectomy with excimer and Ho:YAG lasers

The authors report their experiences using the excimer laser and holmium:YAG laser in arthroscopic meniscal surgery. Histologic and ultrastructural aspects caused by laser irradiation on meniscal tissues are evaluated. Two groups of 10 patients, each suffering from a bucket-handle lesion of the internal meniscus, were used for this study. The histologic results of the study confirm the clinical reliability of the laser even in the presence of different ultrastructural frames.

The human anterior cruciate ligament: histological and ultrastructural observations

In transverse and longitudinal paraffin-embedded sections, the human anterior cruciate ligament (ACL) is made up of wavy bundles of collagen fibres arrayed in various directions, the majority around the axis of the ligament with a few running parallel to it. The fascicles making up the larger bundles are also characterised by this undulating appearance. In thin sections 2 types of collagen fibrils are observed: small (with a single diameter peak at 45 nm) and large (3 peaks at 35, 50 and 75 nm respectively), organised into distinct areas made up of either large or small bundles of fibrils. The numerous fibroblasts that are present appear elongated in the direction of the bundles with branches and short cytoplasmic processes. The elastic system is made up of both elastic and oxytalan fibres. The varied orientation of the bundles in the ACL, the complex ultrastructural organisation and the abundant elastic system make it very different from other ligaments and tendons, providing a structure able to withstand the multiaxial stresses and varying tensile strains imposed upon it.

Histologic and ultrastructural findings of tissue ingrowth. The Leeds-Keio prosthetic anterior cruciate ligament

A light and electron microscopy investigation was performed on a Leeds-Keio ligament removed because of rupture 18 months after implantation to repair an anterior cruciate ligament. The investigation showed fibrous connective tissue on the plane of the main stress force. There was elastin and adequate vascularization interspersed with Type I collagen fibrils in the area most distant from the ligament. The tissue near the Dacron fibers was highly cellular with a matrix of infrequent, thin collagen fibrils and abundant fine granular material. The growth of the host tissue occurred in and around a Leeds-Keio ligament in response to tensile stresses.