Extent of vertical cementing as a predictive factor for radiolucency in revision total knee arthroplasty.

PURPOSE: Limited information is available regarding the effects of cementing extent on implant stability in patients who have undergone revision total knee arthroplasty (TKA). As such, the goals of this study were: (1) to determine the correlation between the extent of vertical cementing and implant loosening; (2) to determine whether the extent of cementing is a potential predictive factor for radiolucency; and (3) to evaluate the minimal amount of cement needed for a stable implant during revision TKA using a hybrid technique. METHODS: One hundred nine stemmed/revision TKAs with a mean follow-up period of 5 years were retrospectively analysed. In each case, a single varus-valgus constrained implant was used and fixed with a hybrid technique. Implant stability was evaluated according to the modified Knee Society radiographic scoring system. The extent of vertical cementing was defined as the longitudinal length from the implant base to the end of the radiopaque line around the stem on radiograph. Its correlation with implant stability was analysed, and the minimal value for a stable implant was evaluated with a receiver operating characteristic (ROC) analysis. RESULTS: The mean extent of vertical cementing was longer in stable implants (femur: p = 0.001, tibia: p = 0.004) and significantly correlated with implant stability (femur: p < 0.001, tibia: p = 0.001). A logistic regression analysis revealed that the risk of loosening was 8.7-16.1 times higher when the extent of cementing was <40 mm, which was located at the stem-implant junction of the modular implant. The minimal extent of vertical cementing was estimated to be 60 mm for a stable femoral implant and 50 mm for a tibial implant. CONCLUSIONS: The hybrid fixation technique with a cementing extent >60 mm for the femur and 50 mm for the tibia was durable at a mean follow-up period of 5 years. Vertical cementing 10-20 mm above the stem-implant junction is recommended when performing revision TKA using this technique. LEVEL OF EVIDENCE: IV.

Comparison of patellar resurfacing versus preservation in high flexion total knee arthroplasty.

PURPOSE: Recently, high flexion design total knee arthroplasty (TKA) has been introduced to improve clinical outcomes. The purpose of this study is to compare the midterm outcomes between patellar resurfacing (PR) and patellar preservation (PP) in high flexion TKA. METHODS: A total of 373 knees of primary TKAs were performed using high flexion design, 339 knees involved PR group and 34 knees involved PP group. After applying exclusion criteria, 1:3 matching was performed by the matching criteria. After matching, 69 knees in PR group and 23 knees in PP group remained. Radiographic outcomes, clinical outcomes, patients' satisfaction, ability and pain related to the high flexion activities were also evaluated. RESULTS: There was no significant difference in radiograph measurements, KS function score and WOMAC score (n.s). However, PR group showed better outcomes in KS knee score (P = 0.001) and HSS score (P = 0.03). There was no significant difference in postoperative satisfaction and ability of high flexion activities between the groups, but the pain at the high flexion activities in PP group was worse than that in PR group. CONCLUSION: In high flexion design of TKA, PR resulted in better midterm outcomes in regard to KS knee score, HSS score and knee pain related to the high flexion activities. The selective PR is recommended when performing primary TKA with high flexion design. LEVEL OF EVIDENCE: IV.

Meniscus allograft transplantation for discoid lateral meniscus: clinical comparison between discoid lateral meniscus and nondiscoid lateral meniscus.

PURPOSE: This study was performed to compare the clinical results of meniscus allograft transplantation (MAT) after total meniscectomy in torn discoid lateral meniscus (DLM) and nondiscoid lateral meniscus (NLM). METHODS: We conducted a retrospective study of 36 patients who underwent MAT. The discoid and nondiscoid groups consisted of 16 and 20 patients, respectively. The mean follow-up period was 32 months. We checked range of motion (ROM), visual analog scale (VAS) score, International Knee Documentation Committee (IKDC) subjective score, Lysholm score, Tegner activity score for clinical evaluation; magnetic resonance imaging (MRI) was checked for objective evaluation. RESULTS: The mean last follow-up VAS score, IKDC subjective score, Lysholm score, Tegner activity score, and subjective satisfaction of the patient were not significantly different between the discoid group and the nondiscoid group. The ROM of the discoid group was significantly decreased compared with that of the nondiscoid group (P < .05). Follow-up MRI was performed in 17 patients (9 from the discoid group and 8 from the nondiscoid group). Mean extrusion of the graft was 2.0 mm in the discoid group and 2.4 mm in the nondiscoid group (P = .344). Relative percentage of extrusion (RPE) was 22.8% in the discoid group and 22.7% in the nondiscoid group (P = .519). CONCLUSIONS: According to the minimal 2-year follow-up observations, MAT in patients with a torn discoid meniscus is an effective method for reducing the pain caused by meniscal deficiency and improving the function of the knee joint. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

Can physical examination predict the intraarticular tear pattern of the anterior cruciate ligament?

PURPOSE: We evaluated the correlation between physical examinations and the tear patterns of the anterior cruciate ligament (ACL). MATERIALS AND METHODS: From January 2003 to May 2007, we reviewed 201 cases of ACL rupture, diagnosed by MRI. Two orthopaedic surgeons (a fellow and a senior surgeon) evaluated the instability of the knee under anaesthesia: physical examinations were the anterior draw test (AD), Lachman test (LT), and pivot shift test (PT). By describing the rupture pattern and the site of the anteromedial (AMB) and posterolateral bundle (PLB) during arthroscopic examination, we analysed the correlation between the physical examination under anaesthesia and arthroscopic findings. RESULTS: In terms of the arthroscopic findings, rupture of the PLB was seen in 83 cases (41.3 %), of the AMB in 24 cases (11.9 %), and of both bundles in 94 cases (46.8 %). The kappa values for the physical examinations between the examiners were 0.963 (AD), 0.92 (LT), and 0.865 (PT). AD and LT above grade 2 did not differ significantly according to the pattern of rupture, but a PT above grade 2 was significantly different in ruptured PLB versus complete rupture. CONCLUSIONS: A PT of more than grade 2 is a reliable physical examination for prediction of ruptured PLB or complete rupture.

Meniscus allograft transplantation: a comparison of medial and lateral procedures.

BACKGROUND: Because of the anatomic and biomechanical differences between the lateral and medial menisci, it is believed that the indications, combined injuries, techniques, and outcomes of the 2 meniscus allograft transplantation (MAT) procedures may be different. HYPOTHESIS: Medial meniscus transplantation (medial group) usually combines concomitant surgeries, such as anterior cruciate ligament (ACL) reconstruction, so the medial group will have worse clinical results than the lateral group (lateral meniscus transplantation). STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: A retrospective study was conducted on 91 patients who underwent MAT (lateral group, n = 56; medial group, n = 35). There were 33 patients with an absence of a concurrent injury (isolated group) and 58 patients with the presence of a concurrent injury (combined group). The mean follow-up was 40 months (range, 24-125 months). Clinical outcomes for range of motion (ROM), visual analog scale (VAS) for pain score, International Knee Documentation Committee (IKDC) subjective score, Lysholm score, and Tegner activity score were evaluated, and an objective evaluation was performed using magnetic resonance imaging (MRI) and second-look arthroscopic surgery. RESULTS: At final follow-up, the mean results for ROM, VAS score, IKDC subjective score, Lysholm score, Tegner activity score, and patient subjective satisfaction were not statistically different between the lateral and medial groups (P > .05). The VAS and Lysholm scores of the isolated group were significantly better than those of the combined group. Follow-up MRI was performed on 35 patients (24 in the lateral group and 11 in the medial group). Mean graft extrusion was 1.7 mm in the lateral group and 2.6 mm in the medial group (P = .075). The relative percentage of extrusion was 19.4% in the lateral group and 32.0% in the medial group (P = .011). Anterior cruciate ligament reconstruction occurred more commonly in the medial group, and cartilage procedures occurred more commonly in the lateral group. CONCLUSION: The clinical results of the lateral group were not different from those of the medial group. More graft extrusion was found in the medial group on MRI, and second-look arthroscopic surgery results of the lateral group were not as good as those of the medial group. The VAS and Lysholm scores of the combined group were worse than those of the isolated group. With regard to concomitant surgery, ACL reconstruction was most common in the medial group and cartilage procedures in the lateral group.

Comparison of clinical results of anatomic posterolateral corner reconstruction for posterolateral rotatory instability of the knee with or without popliteal tendon reconstruction.

BACKGROUND: It is unknown whether popliteal tendon reconstruction is necessary in anatomic posterolateral corner reconstruction, although the tendon has function in the varus and rotatory stability of the knee joint. HYPOTHESIS: Anatomic reconstructions of the posterolateral corner with the popliteal tendon reconstructed will present better clinical and radiographic results than cases with the popliteal tendon not reconstructed. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: The authors retrospectively analyzed 32 cases of anatomic posterolateral corner reconstruction with a minimum 2-year follow-up. There were 17 cases of anatomic reconstruction with popliteal tendon reconstruction and 15 cases without popliteal tendon reconstruction. The authors compared preoperative and postoperative range of motion, varus instability by varus stress test, lateral joint opening on varus stress radiographs, posterolateral rotatory instability by dial test, Tegner activity score, Lysholm score, and International Knee Documentation Committee (IKDC) subjective knee evaluation form and knee examination form between the 2 groups. They also compared posterior translation on posterior stress radiographs in cases with posterior cruciate ligament reconstruction. RESULTS: There was no difference in range of motion, varus stress test, dial test, Tegner score, Lysholm score, or the score by IKDC subjective knee evaluation form. The side-to-side difference in lateral joint opening on the varus stress radiographs significantly improved after anatomic reconstruction in both groups (P < .001, P = .001), but there was no preoperative or postoperative differences between the groups. No difference was found in the grade distribution on the IKDC examination form. In the cases with posterior cruciate ligament reconstruction, there was also no difference in posterior translation between the groups on posterior stress radiographs at the last follow-up. CONCLUSION: No effect of popliteal tendon reconstruction was found in anatomic posterolateral corner reconstruction on the stability and clinical results.