Opening wedge high tibial osteotomy using a monoaxial dynamic external fixator.

PURPOSE: To prospectively assess midterm results in 37 patients (41 knees) who were treated with opening wedge high tibial osteotomy (OW-HTO) with the use of a monoaxial dynamic external fixator (MDEF) for medial knee osteoarthritis. METHODS: Clinical and subjective evaluations were performed using the IKDC and KOOS evaluation forms and the modified Knee Society Clinical Rating System (KSS). Pin tract infections were evaluated according to Checketts-Otterburns classification. Radiographic evaluation included long-standing AP lower limb, standard lateral, Rosenberg and Merchant views. RESULTS: Thirty-six patients (40 knees) were evaluated at a mean follow-up period of 7 years. Ten patients (25 %) developed a minor pin tract infection. Subjective KOOS and IKDC scores showed statistically significant improvement. Clinical evaluation with IKDC and KSS forms showed no patient with instability or a range-of-motion deficit worst than pre-operatively. At MDEF removal, the mechanical axis was on average 4.5° valgus; anatomical axis 6.8° valgus; the Mikulicz' line crossed the tibial plateau on average at 64 % of the width of the tibial plateau measured from medial; the posterior slope 5°; the metaphyseal varus 4.3°; and the Insall/Salvati ratio 1.02. At latest follow-up, five patients had a loss of correction of 1°-2° on mechanical axis and one patient had a loss of correction of 3° on mechanical axis and 4 % of mechanical axis on tibial plateau. CONCLUSIONS: The use of a MDEF to perform an OW-HTO showed a good maintenance of correction achieved with satisfactory midterm outcome results in all patients but three who underwent total knee replacement. The only severe post-operative complication was one case of non-union in a heavy smoker. LEVEL OF EVIDENCE: Prospective and therapeutic study, Level IV.

Patellofemoral function after total knee arthroplasty: gender-related differences.

The purpose of the study was to evaluate patellofemoral results in 2 comparable groups of 50 patients, men and women, undergoing total knee arthroplasty. The average follow-up was 6 years. The implant was posteriorly stabilized with a dome patellar arthroplasty. The patients were studied using Knee Society knee and functional scores and the Hospital for Special Surgery (HSS) patellar score. Radiologic study included standard and weight-bearing axial views and a computed tomographic scan to assess component rotation. The 2 groups achieved satisfactory and similar knee scores; women had a significantly lower functional and patellar scores. The incidence of lateral patellar tilt, subluxation, and lateral impingement was decreased in weight-bearing axial views compared with non-weight bearing. Medial bony impingement was evident only in weight-bearing views and correlated with pain (P < .05).

Comparison between single-and double-bundle anterior cruciate ligament reconstruction: a prospective, randomized, single-blinded clinical trial.

BACKGROUND: Double-bundle ACL reconstruction popularity is increasing with the aim to reproduce native ACL anatomy and improve ACL reconstruction outcome. However, to date, only a few randomized clinical studies have been published. PURPOSE: The aim of this study was to prospectively compare the clinical results of single- and double-bundle ACL reconstruction. STUDY DESIGN: Randomized controlled clinical trial; Level of evidence, 1. METHODS: Seventy patients with a chronic unilateral ACL rupture who underwent arthroscopically assisted ACL reconstruction using a hamstring graft were randomized to receive a single- (SB) or double-bundle (DB) reconstruction. Both groups were comparable with regard to preoperative data. A double-incision surgical technique was adopted in both groups. The graft was fixed by looping the hamstring tendons around a bony (DB) or a metallic (SB) bridge on the tibial side and with interference screws reinforced with a staple on the femur. The same rehabilitation protocol was adopted. Outcome assessment was performed by a blinded, independent observer using the visual analog scale (VAS) score, the new International Knee Documentation Committee (IKDC) form, the Knee Injury and Osteoarthritis Outcome Score (KOOS), and KT-1000 arthrometer evaluation. RESULTS: All the patients reached a minimum follow-up of 2 years. No differences between the 2 groups were observed in terms of KOOS and IKDC subjective score. A statistically significant difference in favor of the DB group was found with the VAS (P < .03). The objective IKDC final scores showed statistically significantly more "normal knees" in the DB group than in the SB group (P = .03). There was 1 stability failure in the DB group and 3 in the SB group. The KT-1000 arthrometer data showed a statistically significant decrease in the average anterior tibial translation in the DB group (1.2 mm DB vs 2.1 mm SB; P < .03). The incidence of a residual pivot-shift glide was 14% in DB and 26% in SB (P = .08). CONCLUSION: In the 2-year minimum follow-up, DB ACL reconstructions showed better VAS, anterior knee laxity, and final objective IKDC scores than SB. However, longer follow-up and accurate instrumented in vivo rotational stability assessment are needed.

Rotational position of femoral and tibial components in TKA using the femoral transepicondylar axis.

Proper femoral and tibial component rotational positioning in TKA is critical for outcomes. Several rotational landmarks are frequently used with different advantages and limitations. We wondered whether coronal axes in the tibia and femur based on the transepicondylar axis in the femur would correlate with anteroposterior deformity. We obtained computed tomography scans of 100 patients with arthritis before they underwent TKA. We measured the posterior condylar angle on the femoral side and the angle between Akagi's line and perpendicular to the projection of the femoral transepicondylar axis on the tibial side. On the femoral side, we found a linear relationship between the posterior condylar angle and coronal deformity with valgus knees having a larger angle than varus knees, ie, gradual external rotation increased with increased coronal deformity from varus to valgus. On the tibial side, the angle between Akagi's line and the perpendicular line to the femoral transepicondylar axis was on average approximately 0 degrees , but we observed substantial interindividual variability without any relationship to gender or deformity. A preoperative computed tomography scan was a useful, simple, and relatively inexpensive tool to identify relevant anatomy and to adjust rotational positioning. We do not, however, recommend routine use because on the femoral side, we found a relationship between rotational landmarks and coronal deformity.

Total knee arthroplasty using a pie-crusting technique for valgus deformity.

UNLABELLED: Valgus deformity correction with total knee arthroplasty is challenging. We hypothesized selective release of the tight lateral structures (pie-crusting technique), and of the lateral retinaculum in case of patellar maltracking, would obtain and maintain correction of the frontal plane deformity, restore patellar tracking and function, and avoid the complications of the extensive releases, including lateral condyle avascularity and residual lateral instability. We followed 48 patients with 53 valgus knees who underwent TKA and were followed a minimum of 5 years (mean, 8 years; range, 5-12 years). Soft tissue balancing of the lateral structures was performed with the pie-crusting technique. We employed either a fixed posterior stabilized or a mobile implant. A lateral release was performed in 67% of the cases. We observed one postoperative complication, a transient postoperative peroneal nerve palsy that spontaneously completely recovered. In 51 of the 53 knees (96%) we achieved alignment within 5 degrees from neutral. One patient had varus instability in extension. No component was revised. The pie-crusting technique reliably corrects moderate to severe fixed valgus deformities with a low complication rate and reasonable mid-term results. The multiple punctures allow gradual stretching of the lateral soft tissues and preservation of the popliteus tendon reducing the risk of posterolateral instability. LEVEL OF EVIDENCE: Level IV, case series. See the Guidelines for Authors for a complete description of levels of evidence.

Methodological models for in vitro amplification and maintenance of human articular chondrocytes from elderly patients.

Articular cartilage defects, an exceedingly common problem closely correlated with advancing age, is characterized by lack of spontaneous resolution because of the limited regenerative capacity of adult articular chondrocytes. Medical and surgical therapies yield unsatisfactory short-lasting results. Recently, cultured autologous chondrocytes have been proposed as a source to promote repair of deep cartilage defects. Despite encouraging preliminary results, this approach is not yet routinely applicable in clinical practice, but for young patients. One critical points is the isolation and ex vivo expansion of large enough number of differentiated articular chondrocytes. In general, human articular chondrocytes grown in monolayer cultures tend to undergo dedifferentiation. This reversible process produces morphological changes by which cells acquire fibroblast-like features, loosing typical functional characteristics, such as the ability to synthesize type II collagen. The aim of this study was to isolate human articular chondrocytes from elderly patients and to carefully characterize their morphological, proliferative, and differentiative features. Cells were morphologically analyzed by optic and transmission electron microscopy (TEM). Production of periodic acid-schiff (PAS)-positive cellular products and of type II collagen mRNA was monitored at different cellular passages. Typical chondrocytic characteristics were also studied in a suspension culture system with cells encapsulated in alginate-polylysine-alginate (APA) membranes. Results showed that human articular chondrocytes can be expanded in monolayers for several passages, and then microencapsulated, retaining their morphological and functional characteristics. The results obtained could contribute to optimize expansion and redifferentiation sequences for applying cartilage tissue engineering in the elderly patients.

Double-bundle "anatomic" anterior cruciate ligament reconstruction: a cadaveric study of tunnel positioning with a transtibial technique.

PURPOSE: The aim of this study was to examine whether a double-bundle anterior cruciate ligament (ACL) reconstruction with a transtibial approach could position the tibial and femoral tunnels accurately in the native bundle attachments. METHODS: In 21 fresh-frozen knees the tibial and femoral attachments of the anteromedial (AM) and posterolateral (PL) bundles were outlined. The AM tibial tunnel guidewire was drilled with the 65 degree Howell tibial guide (Arthrotek, Warsaw, IN) located against the femur in the extended knee. The PL tibial wire was drilled through a prototype attachment to the Howell guide. Of the knees, 14 were available for the femoral part of the study. The AM femoral guidewire used an aimer offset 3 mm from the over-the-top position. The PL wire was drilled transtibially at 70 degrees of flexion, with external rotation and posterior drawer loads being applied. The plateaus and condyles were photographed and the wire positions measured. RESULTS: With regard to the tibia, 17 of 21 AM wires were in the AM bundle attachment (at 61% and 36% of the natural ACL posteroanterior and mediolateral length, respectively) and 19 of 21 PL wires were in the PL bundle attachment (at 28% and 36% of the posteroanterior and mediolateral length, respectively). With regard to the femur, 12 of 14 AM wires and 9 of 14 PL wires were in the correct native bundle attachment. The AM wire was 3% more shallow than the center of the AM attachment (P = .03) and 6% more superior (P < .001), where 100% was the diameter of the posterior lateral condyle. The PL wire was 4% more shallow than the center of the PL attachment (P = .026) and 6% more superior (P < .001). CONCLUSIONS: Anatomic and reproducible tibial guidewire positioning was achieved. Femoral wires were reproducibly positioned, but both were superior to and more shallow than the natural ACL bundle attachments, so further development or a different approach is appropriate. CLINICAL RELEVANCE: The double-bundle reconstruction aims to restore anterior drawer and rotational stability. This technique ensures anatomic tibial positioning. Further improvements are needed with regard to the femur.

Single-and double-incision double-bundle ACL reconstruction.

Double-bundle anterior cruciate ligament (ACL) reconstruction is intended to replicate the anatomy and the function of the anteromedial and posterolateral bundles of the native ACL to improve patients' satisfaction and knee stability. We prospectively assigned 75 consecutive patients with an isolated ACL lesion to one of three sequential groups of 25 patients each. Group I received a single-bundle, single-incision transtibial ACL reconstruction. Groups II and III received a double-bundle reconstruction with a single-incision transtibial technique or a double-bundle, twoincision outside-in technique, respectively. We obtained subjective International Knee Documentation Committee and Knee Injury and Osteoarthritis Outcome Score evaluations and objective International Knee Documentation Committee scores and KT-1000 measurements preoperatively and at followup. All patients reached a minimum followup of 2 years. KT side-to-side difference in Groups I, II, and III were 2.4, 1.6 and 1.4 mm, respectively. Group III had fewer patients with a positive pivot shift than Group I. The double-bundle double-incision outside-in ACL reconstruction resulted in improved anteroposterior stability and less residual pivot shift than single-incision single-bundle technique.

Validation of the 65 degrees Howell guide for anterior cruciate ligament reconstruction.

PURPOSE: To study in cadaver knees the position of the tibial tunnel in anterior cruciate ligament (ACL) reconstruction using the 65 degrees Howell guide (Arthrotek, Ontario, CA). TYPE OF STUDY: Controlled laboratory study in vitro. METHODS: Twenty-one fresh-frozen cadaver knees were used. The ACL was resected and its tibial attachment was demarcated. To drill the guidewire, we used the Howell 65 degrees tibial guide, which references off of the intercondylar roof in extension to avoid impingement. The intra-articular position of the wire was digitized with a digital camera and referred to a transverse axis passing through the over-the-back position and a sagittal axis passing through the lateral aspect of the medial spine. The percentage position of the wire within the ACL attachment was also calculated, taking the posterior and medial limits as the 0% positions. RESULTS: All the wires were within the ACL attachment: 17 were in the ACL posterolateral bundle attachment and the other 4 in the anteromedial. The average distance of the wire from the transverse and sagittal axes was 12 mm (SD, 3 mm) anterior and 1 mm (SD, 1 mm) lateral, respectively. The wire was positioned at 38% (SD, 16%) of the length of the ACL attachment and at 40% (SD, 17%) of the width. Eighty percent of the wires were positioned at between 35% and 48% of the attachment length. CONCLUSIONS: The 65 degrees Howell guide, which positions the tibial tunnel in extension to avoid roof impingement, ensures anatomic positioning of the graft on the tibial side and reproducibility can be expected. CLINICAL RELEVANCE: This study proves that a commonly used drill guide succeeds in placing the ACL graft in the tibial anatomic attachment.

Femoral attachment of the anterior cruciate ligament.

Endoscopic anterior cruciate ligament (ACL) reconstruction is one of the most popular orthopaedic procedures. Correct tunnel positioning is a prerequisite to success. Current surgical techniques are unable to duplicate the complex anatomy and function of the native ACL. Surgery mainly aims at restoring anteroposterior laxity. The ACL is not isometric and only a few fibers are nearly isometric over the full range of motion. However, a nearly isometric behaviour of the ACL graft is desirable. Isometry is mainly influenced by femoral attachment; thus the femoral tunnel position has a greater effect than the tibial on graft length changes. The purpose of this article is to describe the anatomy of the femoral ACL insertion and to discuss the surgical techniques used to replicate it.

Minimally invasive total knee arthroplasty: is it for everybody?

The development of new instrumentation and techniques has led to the rapid advancement of less invasive surgical approaches in total knee arthroplasty (TKA). Compared to the standard approach, minimally invasive surgery (MIS) in TKA was shown to reduce postoperative pain, blood loss, and hospitalization time, and to improve functional recovery. Growing experience with MIS-TKA has defined the proper indications for this technique. With a limited exposure, the skin, capsular tissues, and bone surfaces receive higher stresses because of the retraction required. Several complications relating to the MIS learning curve are now being reported. The reliability of a TKA procedure performed through a mini-incision, and its success, seems to depend on patient selection, surgeon experience, and surgical environment.

Comparison of mobile-bearing and fixed-bearing total knee arthroplasty: a prospective randomized study.

The purpose of this prospective randomized study was to compare the postoperative recovery and early results of 2 groups of patients undergoing total knee arthroplasty: 107 patients received an established fixed-bearing posterior-stabilized prosthesis (Legacy Posterior Stabilized [LPS]), and 103 patients the meniscal-bearing prosthesis (Meniscal Bearing Knee [MBK]). Surgical procedures were the same for both groups except for posterior cruciate ligament management, which was sacrificed in the LPS group and spared but completely released from the tibia in the MBK group. At an average follow-up of 36 months, knee, function, and patellar scores were comparable in both groups. The LPS group showed a significantly higher maximum flexion than the MBK group (112 degrees vs 108 degrees). Using a fixed-bearing or a mobile-bearing design did not seem to influence the short-term recovery and early results after knee arthroplasty. Key words: total knee arthroplasty, mobile bearing, knee prosthesis, meniscal-bearing knee, posterior stabilized, prospective randomized.

Anterior cruciate ligament reconstruction with double-looped semitendinosus and gracilis tendon graft directly fixed to cortical bone: 5-year results.

Forty-three patients who had undergone an anterior cruciate ligament (ACL) reconstruction using a doubled semitendinosus and gracilis graft were prospectively reviewed at 5-year follow-up. All had suffered subacute or chronic tears of the ligament. At surgery, the femoral tunnel was drilled first through the antero-medial portal. The correct position of the femoral and tibial guide wire was checked fluoroscopically. A cortical fixation to the bone was achieved in the femur with a Mitek anchor, directly passing the two tendons in the slot of the anchor, and in the tibia with an RCI screw, supplemented with a spiked washer and bicortical screw. Rehabilitation was aggressive, controlled and without braces. The International Knee Documentation Committee (IKDC) form, KT-1000 arthrometer, and Cybex dynamometer were employed for clinical evaluation. A radiographic study was also performed. At the 5-year follow-up all the patients had recovered full range of motion and 2% of them complained of pain during light sports activities. Four patients (9.5%) reported giving-way symptoms. The KT-1000 side-to-side difference was on average 2.1 mm at 30 lb, and 68% of the knees were within 2 mm. The final IKDC score showed 90% satisfactory results. There was no difference between the 2-year and 5-year evaluations in terms of stability. Extensor and flexor muscle strength recovery was almost complete (maximum deficit 5%). Radiographic study showed a tunnel widening in 32% of the femurs and 40% of the tibias. A correlation was found between the incidence of tibial tunnel widening and the distance of the RCI screw from the joint (the closer the screw to the joint, the lower the incidence of widening). In conclusion, we can state that, using a four-strand hamstring graft and a cortical fixation at both ends, we were able to achieve satisfactory 5-year results in 90% of the patients.

Anterior cruciate ligament reconstruction: bone-patellar tendon-bone compared with double semitendinosus and gracilis tendon grafts. A prospective, randomized clinical trial.

BACKGROUND: The choice of graft for anterior cruciate ligament reconstruction is a matter of debate, with patellar and hamstring tendons being the two most popular autologous graft options. The objective of this study was to determine in a prospective, randomized clinical trial whether two grafts (bone-patellar tendon-bone or doubled hamstring tendons) fixed with modern devices affect the two-year minimum clinical and radiographic outcomes of anterior cruciate ligament reconstruction. METHODS: One hundred and twenty patients with a chronic unilateral rupture of the anterior cruciate ligament underwent arthroscopically assisted reconstruction with use of either autologous bone-patellar tendon-bone or doubled hamstring tendon grafts, in a strictly alternating manner. Both groups were comparable with regard to demographic data, preoperative activity level, mechanism of injury, interval between the injury and the operation, and the amount of knee laxity present preoperatively. The same well-proven surgical technique and aggressive controlled rehabilitation was used. An independent observer, who was blinded with regard to the involved leg and the type of graft, performed the outcome assessment with use of a visual analog scale, the new International Knee Documentation Committee form, the Knee Injury and Osteoarthritis Outcome Score, the Functional Knee Score for Anterior Knee Pain, and an arthrometric and an isokinetic dynamometric evaluation. Radiographs were also made. RESULTS: At the two-year follow-up evaluation, no differences were found in terms of the visual analog score, the Knee Injury and Osteoarthritis Outcome Score, the new International Knee Documentation Committee subjective and objective evaluation scores, the KT-1000 side-to-side laxity measurements, the Functional Knee Score for Anterior Knee Pain, muscle strength recovery, or return to sports activities. In the bone-patellar tendon-bone group, we found a higher prevalence of postoperative kneeling discomfort (p < 0.01) and an increased area of decreased skin sensitivity (p < 0.001). In the hamstring tendon group, we recorded a higher prevalence of femoral tunnel widening (p < 0.01). In this group, a correlation was also found between medial meniscectomy and an increased prevalence of pivot-shift glide (p = 0.035). CONCLUSIONS: We believe that, with use of accurate and proven surgical and rehabilitation techniques, both grafts are an equivalent option for anterior cruciate ligament reconstruction.

High tibial valgus osteotomy for medial gonarthrosis: a 10- to 21-year study.

This retrospective study reviewed the long-term experience with high tibial osteotomy and determined which factors influence the results. Between 1980 and 1989, 120 closing wedge high tibial osteotomies for varus gonarthrosis were performed in 102 patients. Twenty-nine knees were excluded because the patients died (17 knees), were bedridden (7 knees), or lost to follow-up (5 knees). Thirty of the remaining 91 knees had a conversion to total knee replacement (TKR) after 11 years on average, leaving 61 knees with a high tibial osteotomy available for clinical and radiographic evaluation at an average follow-up of 15 years (range: 10-21 years). Of the 91 knees, excellent/good results were found in 49% and fair/poor in 51%. Anatomical femorotibial angle in the 61 knees at follow-up averaged 4.7 degrees +/- 5 degrees of valgus (range: 3 degrees varus to 23 degrees valgus). Alignment obtained at consolidation changed with varus recurrence at follow-up in 14% of 61 knees and did not correlate with the clinical results. Twelve (19%) knees showed a patella baja (Caton ratio <0.6) at follow-up, which correlated with patients immobilized postoperatively by a cylinder cast (P=.04). A valgus alignment at consolidation between 8 degrees and 15 degrees, good muscle strength, and male gender correlated with better results (P<.05). Survivorship analysis, considering an unsatisfactory result or revision to TKR as the endpoint, was 96% at 5 years, 88% at 7 years, 78% at 10 years, and 57% at 15 years. High tibial osteotomy provides symptomatic relief for approximately 10 years, but is unlikely to provide permanent relief.

Posterior cruciate ligament reconstruction with the quadriceps tendon in chronic injuries.

We reviewed 18 patients (knees) operated on because of chronic PCL insufficiency. Preoperatively all the patients were severely disabled and showed a posterior drawer of 10 mm or more. A quadriceps tendon autograft was implanted using an open technique, direct posterior approach, and fixation to the tibia. A free semitendinosus graft was used to reconstruct the lateral collateral ligament in six knees and the medial collateral ligament in two. The patients were reviewed with a mean follow-up of 3.5 years (range 2-5.5) using the IKDC form. Stability was evaluated by stress radiography using the Telos device. The mean side-to-side difference in posterior tibial displacement at 70 degrees of knee flexion at follow-up was 4.8 mm; the side-to-side difference was less than 5 mm in 77% of cases. A side-to-side difference less than 2 mm in lateral joint line opening was found in five of six knees with a lateral collateral ligament reconstruction. Posterior tibial translation was similar in the knees with and those without collateral ligament reconstruction. Only one patient complained of significant pain and giving-way at follow-up. Patellofemoral crepitation was present in nine knees at follow-up although it was symptomatic only in one. The results of this series suggest that posterior cruciate ligament reconstruction using an autologous quadriceps tendon is a valuable option to reconstruct these severe injuries.

Biologic resurfacing of the patella: current status.

The techniques of biologic resurfacing of the patella, like other joint surfaces, are still evolving. Currently none of them is free from criticism. In this regard it is our hope that progress in the basic science will offer in the near future new and more optimistic therapeutic possibilities (i.e., the restoration of a reparative cartilage that is structurally and functionally comparable to the native one). The greater expectancies come perhaps from the present experimental investigations about the combined use of tissue-engineered implants embedded with staminal cells and growth factors. Many problems remain to be solved, however, before reliable applicability in humans. From a general point of view, stem cells obtained from various sources (e.g., adult bone marrow, umbilical cord) offer the same finalities as the embryonic stem cells, without the ethical obstacles related to the latter. Therefore, it may be that restoration of part or all of the articular surface of a joint will be possible by way of these mesenchymal progenitors that have the ability to differentiate into the chondrogenic and osteogenic lines, which is required for the restoration of the various layers of a normal articular cartilage and subchondral bone.