Changes in the orientation of knee functional flexion axis during passive flexion and extension movements in navigated total knee arthroplasty.

PURPOSE: Recently, the functional flexion axis has been considered to provide a proper rotational alignment of the femoral component in total knee arthroplasty. Several factors could influence the identification of the functional flexion axis. The purpose of this study was to analyse the estimation of the functional flexion axis by separately focusing on passive flexion and extension movements and specifically assessing its orientation compared to the transepicondylar axis, in both the axial plane and the frontal plane. METHODS: Anatomical and kinematic acquisitions were performed using a commercial navigation system on 79 patients undergoing total knee arthroplasty with cruciate substituting prosthesis design. The functional flexion axis was estimated from passive movements, between 0° and 120° of flexion and back. Intra-observer agreement and reliability, internal-external rotation and the angle with the surgical transepicondylar axis, in axial and frontal planes, were separately analysed for flexion and extension, in pre- and post-implant conditions. RESULTS: The analysis of reliability and agreement showed good results. The identification of the functional flexion axis showed statistically significant differences both in relation to flexion and extension and to pre- and post-implant conditions, both in frontal plane and in axial plane. The analysis of internal-external rotation confirmed these differences in kinematics (p < 0.05, between 25° and 35° of flexion). CONCLUSIONS: The identification of the functional flexion axis changed in relation to passive flexion and extension movements, above all in frontal plane, while it resulted more stable and reliable in axial plane. These findings supported the possible clinical application of the functional flexion axis in the surgical practice by implementing navigated procedures. However, further analyses are required to better understand the factors affecting the identification of the functional flexion axis. LEVEL OF EVIDENCE: IV.

High rate of implant loosening for uncemented resurfacing-type medial unicompartmental knee arthroplasty.

PURPOSE: To determine the medium-term implant survivorship, the clinical results and the failure mechanisms of a novel unicompartmental arthroplasty for uncemented resurfacing of the medial tibio-femoral compartment. METHODS: Seventy-six consecutive patients were prospectively evaluated with a mean final follow-up of 6 years (SD 5.3 months). In 44 patients, the diagnosis was osteoarthritis, and in 32 patients, it was avascular necrosis of the medial femoral condyle. The Hospital for Special Surgery Score was used for objective clinical evaluation, and a self-administered visual analogue scale was used to quantify residual pain at each observation point. Implant survivorship was determined assuming revision for any reason as endpoint. RESULTS: Nineteen patients were revised (6 with osteoarthritis and 13 with avascular necrosis of the medial femoral condyle). The mean interval time from index surgery to revision was 11.2 months (SD 4.66 months). Implant survivorship was higher in patients with osteoarthritis with respect to those with avascular necrosis of the medial femoral condyle (p = 0.018). Aseptic loosening was the most frequent failure mechanism. Femoral component loosening was reported in five patients and tibial component loosening was reported in other six patients. Assuming revision for any reason as endpoint, an implant survivorship of 74.3 % at 6-year follow-up was determined. In the remaining 57 patients, satisfactory clinical results were obtained. Hospital for Special Surgery Score and visual analogue scale for residual pain showed significant improvements (p < 0.03 and p < 0.045, respectively). CONCLUSIONS: At the present time, the standard cemented implants and the conventional designs for unicompartmental knee replacement still represent the optimal solution. The authors do not recommend the widespread use of this technique. LEVEL OF EVIDENCE: IV.

The adductor tubercle: an important landmark to determine the joint line level in revision total knee arthroplasty.

PURPOSE: The restoration of the physiological femoro-tibial joint line (JL) is important to obtain a good outcome in revision total knee arthroplasty (RTKA). However, its assessment is challenging. The ratio of the distance between the adductor tubercle (AT) JL (ATJL) and the trans-epicondylar femoral width (FW) was proposed as a reliable method. The purpose of this study was to check whether this ratio is a reliable tool to restore the prosthetic JL height in challenging prosthetic revision cases. METHODS: Twenty-one patients (mean age 65.8 years) were recruited. During surgery, FW was measured and ATJL distance was calculated using 0.53 (SD 0.03) as the ratio. After implant positioning, the obtained ATJL line was measured to verify the accuracy of the surgical procedure. Thirteen patients presented a healthy contralateral knee: a comparative radiograph examination was performed to verify the appropriateness of the restored JL height. RESULTS: The intra-operatively calculated ATJL was not significantly different with respect to the measured ATJL obtained after prosthetic component implantation. The comparative analysis between the restored JL and the JL of the contralateral not operated knee was also not statistically significant, thus confirming the appropriateness of the restored JL height. CONCLUSIONS: This study shows that the method which uses an AT to JL distance/FW ratio to determine the JL level, previously applied in primary TKA, is valid when using intra-operatively acquired measurements in RTKA. This is clinically relevant since it represents a reliable tool which helps surgeons to restore the JL level in challenging prosthetic revision cases. LEVEL OF EVIDENCE: Case series, Level IV.

Good survivorship of all-polyethylene tibial component UKA at long-term follow-up.

PURPOSES: To determine the long-term survival rate of an all-polyethylene tibial unicompartmental knee arthroplasty (UKA) in a large series of consecutive patients and to investigate the possible factors that could influence the outcome. METHODS: A retrospective evaluation of 273 patients at 6-13 years of follow-up was performed. Clinical evaluation was based on KSS and WOMAC scores. Subjective evaluation was based on a visual analogue scale for pain self-assessment. Radiographic evaluation was performed to assess femoral-tibial angle (FTA), posterior tibial slope (PTS) and tibial plateau angle (TPA). A Kaplan-Meier survival analysis was performed assuming revision for any reason as primary endpoint. RESULTS: The 10-year implant survivorship was 87.6%. Twenty-five revisions (9.2%) were performed, and aseptic loosening of the tibial component was the most common failure mode (11 cases, 4%). The comparison of survival rate according to age at surgery did not show significant difference. Age at surgery, FTA, TPA and PTS were not related to higher risk of revision. No correlations were found between BMI, age at surgery and clinical scores. Finally, no statistical differences of radiographic measurements were found between revisions and non-revisions. CONCLUSIONS: The present study has demonstrated on a large series of patients that UKA with an all-polyethylene tibial component, with an accurate technique and a proper patient selection, can provide a satisfactory clinical and functional outcome and a good overall survivorship of the implant at long-term follow-up. These advantages could be achieved at a lower cost. LEVEL OF EVIDENCE: Retrospective Therapeutic Study, Level IV.

Unicompartmental knee arthroplasty in patients over 75 years: a definitive solution?

INTRODUCTION: The purpose of this study was to perform a mid-long-term clinical and radiographic evaluation of the results obtained in patients older than 75 years treated with minimally invasive unicompartmental knee arthroplasty (UKA). The hypothesis was that UKA is a viable solution for the definitive treatment of localized disease in this age group, with good results and a low failure rate. METHODS: An all-poly tibial component UKA was applied with a minimally invasive technique. Sixty-seven knees in patients with a minimum age of 75 years were evaluated at mean 9 years' follow-up. The Oxford knee score, Knee Society Score, WOMAC score, Visual Analogue Scale (VAS) for pain self-assessment and range of motion (ROM) were determined, as well as weight-bearing antero-posterior and laterolateral radiographs. RESULTS: All clinical scores, as well as VAS and ROM, improved significantly at 9-year follow-up, and the outcome was considered good or excellent in 92.6% of the patients. Radiographic results showed that both tibial plateau angle and posterior tibial slope angles were maintained, whereas femoro-tibial angle was significantly changed at follow-up. Further analysis showed no significant correlation between clinical scores and body mass index, whereas the clinical outcome was correlated with the ROM obtained. Only two failures and one major post-operative complication were observed. CONCLUSIONS: UKA is a viable option for treating unicompartmental knee osteoarthritis. With the proper indications and an accurate technique UKA may be indicated also in very elderly patients with reduced complications and morbidity, and excellent survivorship.

Deep-dished highly congruent tibial insert in CR-TKA does not prevent patellar tendon angle increase and patellar anterior translation.

PURPOSE: Starting from the hypothesis that a deep-dished highly congruent tibial insert in cruciate-retaining total knee arthroplasty would prevent the increase in patellar tendon angle and anterior patellar translation by reducing the paradoxical anterior femoral translation, the main purpose of the present study was to investigate the effect of this prosthesis design, and secondary to assess the clinical outcomes at 6-month follow-up. METHODS: Twenty patients treated with cruciate-retaining total knee arthroplasty with navigation technique were enrolled and prospectively followed up at 6 months. The median value of age was 71 years (57-83). Before and after surgery, the following parameters were calculated: patellar tendon angle, anterior-posterior and medio-lateral patellar translation, patellar height and range of motion. All patients were assessed with the SF-36 Physical Functioning and the Knee injury and Osteoarthritis Outcome Score ADL scores. RESULTS: Patellar tendon angle and anterior patellar translation significantly increased in post-operative conditions (p < 0.0001); a statistically significant medial patellar translation was found (p < 0.0001), while patellar height did not show any difference between pre- and post-operative conditions (n.s). A significant correlation was found between patellar tendon angle and anterior patellar translation and the clinical scores (p < 0.0417). There was a significant post-operative decrease (p < 0.0033) in the range of motion. CONCLUSIONS: The present study failed to demonstrate that deep-dished highly congruent tibial insert prevents the anterior translation of the patella in cruciate-retaining total knee arthroplasty, thus causing inferior clinical scores. It provided useful information about the biomechanical role of the patella in total knee arthroplasty, allowing to choose the most appropriate surgical approach. LEVEL OF EVIDENCE: Case series, Level IV.

Roentgen stereophotogrammetric analysis: an effective tool to predict implant survival after an all-poly unicompartmental knee arthroplasty-a 10 year follow-up study.

PURPOSE: The main purpose of the present study was to determine long-term implant fixation of 15 unicompartmental knee arthroplasty (UKAs) with an all-poly tibial component using Roentgen stereophotogrammetric analysis (RSA) at a mean 10-year follow-up. The secondary purpose was to investigate whether the progressive loss of implant's fixation correlates with a reduction in Knee society score (KSS). METHODS: Fifteen non-consecutive patients with primary knee osteoarthritis received a UKA with an all-poly tibial component were assessed using KSS scores pre-operatively and post-operatively and RSA on day 2 after surgery, then at 3, 6, and 12 months and yearly thereafter. The mean last follow-up was 10 years. RESULTS: An increase in maximum total point motion (MTPM) values from 6 months to 1 year post-operatively was found respect to post-operative reference. Implants' displacement values were always <2 mm during the first 6 months, and then, two different trends were noticed in revised and non-revised implants. MTPM increase between 1 and 2 years of follow-up in non-revised UKAs was always <0.2 mm, whereas it was >0.2 mm in revised UKAs. A linear and negative correlation with statistical significance was found between MTPM and both clinical and functional KSS scores (p < 0.001). CONCLUSION: Also in a long-term follow-up evaluation, RSA is an effective tool to predict functional results after an all-poly UKA providing also a relevant predictive value at 1 year follow-up, and this can be very useful for both patients and surgeons. LEVEL OF EVIDENCE: Diagnostic studies, Level III.

Analysis of knee functional flexion axis in navigated TKA: identification and repeatability before and after implant positioning.

PURPOSE: Providing correct rotational alignment of femoral component in total knee arthroplasty (TKA) is mandatory to achieve correct kinematics, good ligament balance and patellar tracking. The purpose of this study was to evaluate potential clinical applications of functional flexion axis (FFA) by analysing the differences between pre- and post-implant placement. This evaluation was supported by the analysis of repeatability, assessing the robustness of the proposed method. METHODS: Anatomical acquisitions and passive kinematics were acquired on 87 patients undergoing TKA using a commercial navigation system. Knee FFA was estimated, before and after implant positioning, from three flexion-extension movements between 0 and 120°. The angle between FFA and transepicondylar axis was analysed in frontal and axial planes. Repeatability coefficient and intraclass correlation coefficient (ICC) were used to analyse the reliability and the agreement in identifying the axis. RESULTS: The analysed angle presented differences between pre- and post-operative conditions only in the frontal plane (from -8.3 ± 5.5° to -2.8 ± 5.3°) (p < 0.0001). There was good intraobserver reliability and agreement. Repeatability coefficient ranged between 4.4° (3.7-4.9°) and 3.4° (2.9-3.8°), the ICC between 0.87 (0.83-0.91) and 0.93 (0.90-0.95) and the standard deviation ranged between 1.3 and 1.0°. CONCLUSIONS: The present study demonstrated that TKA affected the estimation of FFA only in the frontal plane. This method reported good repeatability, demonstrating its usefulness for clinical purposes particularly to evaluate rotational positioning of the femoral component in the axial plane. LEVEL OF EVIDENCE: Case series, Level IV.

Three different cruciate-sacrificing TKA designs: minor intraoperative kinematic differences and negligible clinical differences.

PURPOSE: The goal of this study was to compare three types of mobile-bearing posterior cruciate ligament (PCL)-sacrificing TKA. The hypothesis was that the three designs provide differences in flexion stability and femoral rollback and improved clinical score at 2-year follow-up. METHODS: Three groups of patients, divided according to implant design, were analysed retrospectively. All operations were guided by a non-image-based navigation system that recorded relative femoral and tibial positions in native and implanted knees during: passive range of motion and anterior drawer test at 90° flexion. WOMAC, KSS and SF36 scores were collected pre-operatively and at 2-year follow-up. RESULTS: There are no differences in kinematic or clinical performance of the three implants, except for the antero-posterior translation during stress test in flexion: only Cohort B had comparable pre- and post-operative laxity test values (p < 0.001). All three TKA designs allowed to maintain pre-operative tibial rotation pattern through all range of knee flexion. All clinical scores of the three patient cohorts were significantly improved post-operatively compared to the pre-operative values (p < 0.001). Moreover, we found no differences among post-operative results of the three designs. CONCLUSION: Despite design variations, mobile-bearing PCL-sacrificing TKA reproduces femoral rollback and screw-home with little or no difference in clinical or functional scores at a follow-up of 2 years. LEVEL OF EVIDENCE: III.

Tibial tubercle osteotomy or quadriceps snip in two-stage revision for prosthetic knee infection? A randomized prospective study.

BACKGROUND: Although 7% to 38% of revision total knee arthroplasties (RTKAs) are attributable to prosthetic knee infections, controversy exists regarding the best surgical approach while reducing the risk of extensor mechanism complications and the reinfection rate. QUESTIONS/PURPOSES: We compared The Knee Society Score(©) (KSS), incidences of complications, maximum knee flexion, residual extension lag, and reinfection rate in patients with prosthetic knee infections treated with two-stage RTKAs using either the tibial tubercle osteotomy (TTO) or the quadriceps snip (QS) for exposure at the time of reimplantation. METHODS: We prospectively followed 81 patients with chronic prosthetic knee infections treated between 1997 and 2004. Patients were randomized to receive a TTO or QS for exposure at the time of reimplantation. All patients had the same rehabilitation protocol. The minimum followup was 8 years (mean, 12 years; range, 8-15 years). RESULTS: Patients in the TTO group had a higher mean KSS than the QS group (88 versus 70, respectively). Mean maximum knee flexion was greater in the TTO group (113° versus 94°); with a lower incidence of extension lag (45% versus 13%). We observed no differences in reinfection rate between groups. CONCLUSIONS: We found the TTO combined with an early rehabilitation protocol associated with superior KSS did not impair extensor mechanism function or increase the reinfection rate. We believe a two-stage RTKA with TTO is a reasonable approach for treating prosthetic knee infections. LEVEL OF EVIDENCE: Level I, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

The adductor tubercle: a reliable landmark for analysing the level of the femorotibial joint line.

PURPOSE: The ratio of femoral width and distance from medial epicondyle to joint line helps estimate the femoral joint line position from femoral width. The approximately radial position of the medial epicondyle on femoral condyle spheres is probably responsible for this relationship, The adductor tubercle approximately lies diametrically opposite to the joint line on condylar sphere. Then, a linear correlation could also exist between the femoral width and distance of adductor tubercle to joint line and is the purpose of the current study. METHODS: Femoral width, along with the distance to joint line from the medial epicondyle, the adductor tubercle and fibular pole, was measured on 110 standard antero-posterior knee radiographs. Correlation between femoral width and these measurements was evaluated. The individual ratio of FW with adductor tubercle joint line, medial epicondyle joint line and fibula joint line was calculated using linear regression analysis. Intra-observer and inter-observer reliability was assessed. RESULTS: Linear correlation was found between femoral width and distance of adductor tubercle to joint line (r = 0.83). It was more reliable than the correlation between femoral width and distance from medial epicondyle to joint line (r = 0.52). Inter-observer repeatability was better for distance from adductor tubercle to joint line than for distance from medial epicondyle to joint line. CONCLUSIONS: We conclude that adductor tubercle can be used as a morphologic landmark to determine the knee joint line position, because a linear correlation between femoral width and distance from the adductor tubercle to the joint line was found.

Minimum thickness of all-poly tibial component unicompartmental knee arthroplasty in patients younger than 60 years does not increase revision rate for aseptic loosening.

PURPOSE: Management of unicompartmental knee osteoarthritis in middle-aged patients is a challenging problem. Despite its functional advantages, UKA still raises questions concerning implant survivorship and an increased revision risk for aseptic loosening mainly due to polyethylene wear. The main purpose of the present study was to investigate whether using the minimum thickness of an all-poly tibial UKA in patients under 60 years of age increases the revision rate for aseptic loosening. The secondary purposes were to compare implant survivorship with data reported in literature and to prospectively evaluate the clinical outcome in this selected group of patients. METHODS: Thirty-three consecutive patients under 60 years of age at the time of surgery with isolated medial compartment osteoarthritis underwent a unilateral medial UKA from 2002 to 2005 and were prospectively followed. A Kaplan-Meier analysis was performed to determine the 8-year implant survivorship with revision for any reason as endpoint. KSS, WOMAC, Tegner-Lysholm, Tegner and VAS scores were prospectively evaluated at 3- to 8-year follow-up. Weight-bearing radiographs were collected pre-operatively and at 3- to 8-year follow-up to prospectively evaluate hip-knee-ankle angle (HKA), femoro-tibial angle (FTA), tibial plateau angle and posterior tibial slope. RESULTS: The 8-year Kaplan-Meier survivorship with revision for any reason as endpoint was 83 %. Five failures were reported, and in 3 patients' aseptic loosening of the tibial component was the reason for failure. All clinical scores significantly improved at 3-year follow-up, and no further modification was demonstrated up to 8-year follow-up. HKA, FTA and TPA had a significant difference at 3-year follow-up with respect to pre-operative values (p < 0.01) and no further difference at 8-year follow-up was found. CONCLUSIONS: The present study failed to demonstrate an increased revision rate for aseptic loosening of the implant in patients under 60 years of age, who received an all-poly tibial component UKA using the minimum thickness of the implant in all cases.

Is unicompartmental arthroplasty an acceptable option for spontaneous osteonecrosis of the knee?

BACKGROUND: The literature suggests survivorship of unicompartmental knee arthroplasties (UKAs) for spontaneous osteonecrosis of the knee ranges from 93% to 97% at 10 to 12 years. However, these data arise from small series (23 to 33 patients), jeopardizing meaningful conclusions. QUESTIONS/PURPOSES: We determined (1) the longer-term survivorship of UKAs in a larger group of patients with spontaneous osteonecrosis of the knee; (2) their subjective, symptomatic, and functional outcomes; and (3) the percentage of failures and reasons for failures to identify relevant indications, contraindications, and technical parameters for treatment with a modern implant design. METHODS: We retrospectively evaluated all 84 patients with late-stage spontaneous osteonecrosis of the knee who had a medial UKA from 1998 to 2005. All patients had preoperative MRI to confirm the diagnosis, exclude metaphyseal involvement, and confirm the absence of major degenerative changes in the lateral and patellofemoral compartments. The mean age of the patients at surgery was 66 years and mean BMI was 28.9. We conducted Kaplan-Meier survival analysis using revision for any reason as the end point. Minimum followup was 63 months (mean, 98 months; range, 63-145 months). RESULTS: Ten-year survivorship was 89%. Ten revisions were performed; the most common reasons were subsidence of the tibial component (four) and aseptic loosening of the tibial component (three). No patient underwent revision for progression of osteoarthritis in the lateral or patellofemoral compartments. CONCLUSIONS: Our data suggest spontaneous osteonecrosis of the knee may be an indication for UKA, provided secondary osteonecrosis of the knee is ruled out, preoperative MRI documents the absence of disease in other compartments, and there is no overcorrection in any plane. LEVEL OF EVIDENCE: Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Over-the-top double-bundle revision ACL reconstruction.

Revision ACL presents many technical issues that are not seen in the primary ACL reconstruction. A variety of surgical techniques for revising ACL reconstruction have been described in the literature to address these concerns. The purpose of this article is to present a novel technique consisting in a non-anatomic double-bundle ACL revision reconstruction, using a fresh-frozen Achilles tendon allograft with soft tissue fixation. This technique is a valid treatment option when faced with a complex scenario such as ACL revision surgery.

Long-term outcomes after repair of recurrent post-traumatic anterior shoulder instability: comparison of arthroscopic transglenoid suture and open Bankart reconstruction.

PURPOSE: The purpose of this study is to report long-term outcomes of the arthroscopic modified Caspari technique compared to an open capsular shift surgery to treat post-traumatic anterior shoulder recurrent instability. The hypothesis was that the open surgery group would show higher degenerative changes than to the modified Caspari technique group after a follow-up from 10 to 17 years. METHODS: One hundred and ten nonrandomized consecutive patients who underwent a surgical repair of recurrent unilateral anterior shoulder instability between 1990 and 1999 were retrospectively analyzed. Eighty-two patients were available for long-term follow-up. In particular, 49 patients (59.8%) (group A) were treated with arthroscopic transglenoid modified Caspari suturing technique (mean follow-up 13.7 ± 2.2 years), whereas 33 patients (40.2%) (group B) were treated with combined open capsular shift and Bankart repair (mean follow-up 15.7 ± 2.2 years). Patients were evaluated according to the failure rate (re-dislocation), Rowe, UCLA, and Constant scores. Radiological osteoarthritis changes were ranked according to Samilson score. RESULTS: There were no statistically significant differences between the two groups concerning the failure rate (n.s.), Rowe (n.s.), UCLA (n.s.), and Constant (n.s.) scores. Group A: re-dislocation rate 12.5% (6 re-dislocations), Rowe 85.0 ± 22.6, UCLA 26.4 ± 4.8, and Constant 86.3 ± 16.7. Group B: re-dislocation rate 9% (3 re-dislocations), Rowe 83.2 ± 24.4, UCLA 26.9 ± 4.2, and Constant 87.4 ± 14.1. Radiographic findings of osteoarthritis: 2 severe (4%), 4 moderate (8%), and 12 mild (25%) in group A; 2 severe (6%), 4 moderate (12%), and 9 mild (27%) in group B; differences between groups were not statistically significant (n.s). CONCLUSIONS: The results after both techniques were good in majority of patients, with no significant differences in terms of re-dislocation and osteoarthritis development. Compared to the current literature, the recurrence rate was high in both groups. The modified Caspari technique could be an arthroscopic alternative for older, non-athletic shoulders. LEVEL OF EVIDENCE: Therapeutic Study-Retrospective Comparative Study, Level III.

Ten- to 15-year clinical and radiographic results for a compression molded monoblock elliptical acetabular component.

The aim of this study was to report the long-term results from a previously published midterm follow-up of a titanium monoblock, elliptical acetabular component. A total of 258 primary total hip arthroplasties (212 patients) with a monoblock, acetabular component were followed up for a mean period of 11.1 years (10-15). Average yearly wear rate was 0.08 mm/y (0.0009-0.32). Acetabular radiolucencies were present in 6 hips (2.4%); all were nonprogressive and present in acetabular zone I. Acetabular osteolysis was present in 5 patients (5 hips, 1.9%); all cups were stable. Four acetabular components were revised, 3 because of recurrent instability. No acetabular components were revised for polyethylene wear or dissociation, acetabular osteolysis, loosening, or deep infection. This monoblock design demonstrates excellent long-term survival and low rate of osteolysis.

Arthroscopic-assisted focal resurfacing of the knee: surgical technique and preliminary results of 13 patients at 2 years follow-up.

PURPOSE: The purpose of this study is to describe an arthroscopic-assisted surgical technique for focal resurfacing of medial tibio-femoral compartment and to present the preliminary clinical and radiographic results in a case series of 13 consecutive patients at a mean follow-up of 29 months. METHODS: All patients were treated with the presented procedure for Ahlback grade 3 medial compartment osteoarthritis. Subjective evaluation was based on a visual analog scale for pain self-assessment. Objective clinical evaluation was based on Hospital for Special Surgery score. Range of motion was evaluated with a manual goniometer. Radiographic evaluation compared hip-knee-ankle angle pre- and post-operatively. RESULTS: Clinical and functional results were satisfactory. Hospital for Special Surgery score and visual analog scale for pain self-assessment showed significant improvements (P < 0.0001 and P = 0.0002, respectively). ROM and axial alignment were not significantly different respect to pre-operative values. CONCLUSIONS: Despite the small sample size and short follow-up, this study has shown that an arthroscopic-assisted focal resurfacing of the knee in selected cases can be a viable option for early onset degenerative joint disease, providing satisfactory pain relief and good functional results at 2 years follow-up. LEVEL OF EVIDENCE: Retrospective case series, Level IV.

Single-bundle patellar tendon versus non-anatomical double-bundle hamstrings ACL reconstruction: a prospective randomized study at 8-year minimum follow-up.

PURPOSE: The purpose of this study was to compare subjective, objective and radiographic outcome of the lateralized single-bundle bone-patellar tendon-bone autograft with a non-anatomical double-bundle hamstring tendons autograft anterior cruciate ligament (ACL) reconstruction technique at long-term follow-up. METHODS: Seventy-nine non-consecutive randomized patients (42 men; 37 women) with unilateral ACL insufficiency were prospectively evaluated, before and after ACL reconstruction by means of the above-mentioned techniques, with a minimum follow-up of 8 years (range 8-10 years; mean 8.6 years). In the double-bundle hamstrings technique, we used one tibial and one femoral tunnel combined with one "over-the-top" passage, cortical staple's fixation and we left intact hamstrings' tibial insertion. Patients were evaluated subjectively and objectively, using IKDC score, Tegner level, manual maximum displacement test with KT-2000™ arthrometer. Radiographic evaluation was performed according to IKDC grading system, and re-intervention rate for meniscal lesions was also recorded. RESULTS: The subjective and objective IKDC were similar in both groups while double-bundle hamstrings group showed significantly higher Tegner level (P = 0.0007), higher passive range of motion recovery (P = 0.0014), faster sport resumption (P = 0.0052), lower glide pivot-shift phenomenon (P = 0.0302) and lower re-intervention rate (P = 0.0116) compared with patellar tendon group. Radiographic evaluation showed significant lower objective degenerative changes in double-bundle hamstrings group at final follow-up (P = 0.0056). CONCLUSION: Although both techniques provide satisfactory results, double-bundle ACL reconstruction shows better functional results, with a faster return to sport activity, a lower re-operation rate and lower degenerative knee changes.

Three-Dimensional Co-Culture System of Human Osteoblasts and Osteoclast Precursors from Osteoporotic Patients as an Innovative Model to Study the Role of Nutrients: Focus on Vitamin K2.

Several natural compounds, such as vitamin K2, have been highlighted for their positive effects on bone metabolism. It has been proposed that skeletal disorders, such as osteoporosis, may benefit from vitamin K2-based therapies or its regular intake. However, further studies are needed to better clarify the effects of vitamin K2 in bone disorders. To this aim, we developed in vitro a three-dimensional (3D) cell culture system one step closer to the bone microenvironment based on co-culturing osteoblasts and osteoclasts precursors obtained from bone specimens and peripheral blood of the same osteoporotic patient, respectively. Such a 3-D co-culture system was more informative than the traditional 2-D cell cultures when responsiveness to vitamin K2 was analyzed, paving the way for data interpretation on single patients. Following this approach, the anabolic effects of vitamin K2 on the osteoblast counterpart were found to be correlated with bone turnover markers measured in osteoporotic patients' sera. Overall, our data suggest that co-cultured osteoblasts and osteoclast precursors from the same osteoporotic patient may be suitable to generate an in vitro 3-D experimental model that potentially reflects the individual's bone metabolism and may be useful to predict personal responsiveness to nutraceutical or drug molecules designed to positively affect bone health.

Minimally invasive unicompartmental knee replacement: retrospective clinical and radiographic evaluation of 83 patients.

We performed a retrospective clinical and radiographic evaluation of 83 nonconsecutive patients operated in our institute between February 1996 and March 2003 with a mean follow-up of 60 months to assess the efficiency of unicompartmental knee replacement (UKR) performed with a minimally invasive technique. The aim of this study was to correlate the clinical outcome with the pre- and post-operative alignment and with implant positioning on coronal and sagittal plane. Eighty-three nonconsecutive patients (60 males, 23 females) underwent cemented UKR (De Puy Preservation Uni with all-poly tibial component), for both medial OA (80 patients) and AVN of the medial femoral condyle (3 patients). All patients were available at final follow-up evaluation, and they all presented an evident varus alignment at pre-operative clinical and radiographic evaluation. At radiographic measurement, we considered a knee with femoro-tibial angle (FTA) > 175 degrees as varus knee, 170 degrees < FTA < 175 degrees as normal knee and a knee with a FTA < 170 degrees as a valgus knee. Moreover, we considered a tibial plateau angle (TPA) > 90 degrees for valgus knee and a TPA < 90 degrees for varus knee. According to Hospital for Special Surgery (HSS) scoring system, at a mean follow-up of 60 months, 61 (74%) cases were excellent (100-85 points), 15 (18%) cases were good (84-70 points) and 7 cases (8%) had fair results (<70 points). In our series, patients with an excellent clinical result presented a mean varus deformity of 7.2 degrees (3.6 degrees-10.8 degrees) pre-operatively. According to literature, we demonstrated that a small amount of undercorrection with a small amount of residual varus deformity of 3 degrees-5 degrees is the goal to be reached in order to avoid both rapid degeneration of the nonreplaced compartment and the premature loosening of the replaced compartment. We performed a mean axial correction of 5 degrees (SD 3.9 degrees), leaving a mean axial varus deformity of 2.2 degrees in the excellent group. In our series, the group with excellent results also showed a post-operative PTS of 7 degrees (2.4 degrees-11.6 degrees), while mean pre-operative PTS was 6.5 degrees (2.7 degrees-10.3 degrees). In this study, results have shown that minimally invasive UKR producing a small amount of varus undercorrection in selected patients with medial tibio-femoral osteoarthritis or moderate avascular necrosis of the medial femoral condyle provides excellent clinical and functional results. Overcorrection of varus malalignment with a UKR may produce both rapid degeneration of the lateral tibio-femoral compartment and the early failure of the replaced compartment.