Niklaus F. Friederich

Improperly placed anterior cruciate ligament grafts: correlation between radiological parameters and clinical results

Abstract Despite increasing knowledge on knee biomechanics and refined operative techniques, an increasing number of patients are being seen with failed anterior cruciate ligament (ACL) reconstruction. Failure of the reconstruction and further damage to the knee are correlated with improper placement of the graft, which interferes with graft biology and biomechanical demands. Between 1994 and 1995, 63 patients with improperly placed ACL grafts were referred to our institution because of persistent knee instability and pain. A method for analysis of the femoral drill hole on radiography was developed. Before reoperation the radiograph was evaluated by our method, noting the clinical aspects according to the recommendations of the International Knee Documentation Committee (IKDC). The femoral placement of the ACL graft could easily be defined on the lateral and anteroposterior tunnel radiography. The most common error was a femoral placement anterior to the anatomical insertion of the ACL. A significant correlation (P < 0.05) was found between femoral placement of the graft in the sagittal plane and clinical results: the IKDC score declined with increasing distance of the graft from the most isometric bundle of the ACL in the anteroposterior direction.

Occurrence of free nerve endings in the soft tissue of the knee joint A histologic investigation

We present a comprehensive histologic study of neu rologic structures in 18 static and dynamic knee struc tures of 8 cadaveric knees. Qualitative and quantitative measurements of the incidence of free nerve endings in the structures were recorded. The highest amounts of afferent nerve fibers type IVa were found in the retinacula, the patellar ligament, the pes anserinus, and in the ligaments of Wrisberg and Humphry; the lowest amount was found in the anterior cruciate ligament. There is a positive correlation between the number of mechanoreceptors per standardized area unit and the clinical presentation of certain knee disorders.

The position and orientation of total knee replacement components: A COMPARISON OF CONVENTIONAL RADIOGRAPHS, TRANSVERSE 2D-CT SLICES AND 3D-CT RECONSTRUCTION

We studied the intra- and interobserver reliability of measurements of the position of the components after total knee replacement (TKR) using a combination of radiographs and axial two-dimensional (2D) and three-dimensional (3D) reconstructed CT images to identify which method is best for this purpose. A total of 30 knees after primary TKR were assessed by two independent observers (an orthopaedic surgeon and a radiologist) using radiographs and CT scans. Plain radiographs were highly reliable at measuring the tibial slope, but showed wide variability for all other measurements; 2D-CT also showed wide variability. 3D-CT was highly reliable, even when measuring rotation of the femoral components, and significantly better than 2D-CT. Interobserver variability in the measurements on radiographs were good (intraclass correlation coefficient (ICC) 0.65 to 0.82), but rotational measurements on 2D-CT were poor (ICC 0.29). On 3D-CT they were near perfect (ICC 0.89 to 0.99), and significantly more reliable than 2D-CT (p < 0.001). 3D-reconstructed images are sufficiently reliable to enable reporting of the position and orientation of the components. Rotational measurements in particular should be performed on 3D-reconstructed CT images. When faced with a poorly functioning TKR with concerns over component positioning, we recommend 3D-CT as the investigation of choice.

Midterm and Long-term Results After Arthroscopic Suture Repair of Isolated, Longitudinal, Vertical Meniscal Tears in Stable Knees

Background The long-term outcome of meniscal suture repair has not been firmly established. Purpose To compare the midterm and long-term functional and radiographic outcome of meniscal suture repairs with the natural history of the uninjured knees of each of a cohort of patients. Study Design Cohort study; Level of evidence, 3. Methods Eighty-eight patients with an isolated, longitudinal, vertical tear of one of the menisci within a stable knee were arthroscopically treated with a meniscal suture repair. No patient had a previous surgery, and no additional chondral lesion was present. The opposite knee of each patient was uninjured. Both knees of each patient were examined clinically and radiographically in a retrospective follow-up 5 to 17 years (mean, 10 years) after meniscal repair. Results Three patients with postoperative complications and 21 patients whose menisci had to be removed because of rerupture were excluded from further evaluation for purposes of this study. The remaining 64 patients reached a mean Tegner activity level of 6 points (range, 3-10 points) and achieved a mean Lysholm score of 94 points (range, 26-100 points). Osteoarthritis was found in 46 of the injured knees, compared with 27 of the uninjured knees (P = .004). However, 42 of the patients had no difference in the grade of osteoarthritis between the injured knee and the uninjured knee, 19 had a difference of 1 grade, 2 had a difference of 2 grades, and 1 had a difference of 3 grades. Conclusion Arthroscopic meniscal repair for isolated longitudinal meniscal injuries in stable knees yields favorable functional results, but its effects on the risk of secondary osteoarthritis are not clear.

A novel standardized algorithm for evaluating patients with painful total knee arthroplasty using combined single photon emission tomography and conventional computerized tomography

SPECT/CT is a promising diagnostic modality in patients with painful total knee arthroplasty (TKA). The purpose of this study is to introduce a novel standardized SPECT/CT algorithm and evaluate its clinical application and reliability. A novel SPECT/CT localization scheme consisting of 9 tibial, 9 femoral and 4 patellar regions on standardized axial, coronal and sagittal slices is proposed. It was piloted in 18 consecutive patients with post TKA pain. The tracer activity on SPECT/CT was recorded using a color-coded scale (0–10). The inter- and intra-observer reliability was assessed for localization and tracer activity. The prosthetic component position was assessed in the CT images after 3D reconstruction using standardized frames of reference. The median inter- and intra-observer differences and ranges of the measured angles were calculated along with the ICC values for inter- and intra-observer reliability. The localization scheme showed very high inter- and intra-observer reliabilities for all regions. The measurement of component position was highly reliable in all cases with sufficient visibility of anatomical landmarks. The median inter-observer difference between alignment measurements for tibial and femoral components was less than 3° (range 0°–6°). The median intra-observer variability for these was less than 2° (range 0°–5°). The SPECT/CT algorithm presented is both reliable and useful in the management of patients with painful TKA. It combines biomechanical and metabolic data (tracer localization) providing an extra dimension to the understanding of this difficult condition. The clinical value of SPECT/CT in patients with unexplained pain following TKA should be further investigated.

Clinical value of SPECT/CT for evaluation of patients with painful knees after total knee arthroplasty- a new dimension of diagnostics?

BackgroundThe purpose of our study was to evaluate the clinical value of hybrid SPECT/CT for the assessment of patients with painful total knee arthroplasty (TKA).MethodsTwenty-three painful knees in patients following primary TKA were assessed using Tc-99m-HDP-SPECT/CT. Rotational, sagittal and coronal position of the TKA was assessed on 3D-CT reconstructions. The level of the SPECT-tracer uptake (0-10) and its anatomical distribution was mapped using a validated localization scheme. Univariate analysis (Wilcoxon-Mann-Whitney, Spearmean`s-rho test, p < 0.05) was performed to identify any correlations between component position, tracer uptake and diagnosis.ResultsSPECT/CT imaging changed the suspected diagnosis and the proposed treatment in 19/23 (83%) knees. Progression of patellofemoral OA (n = 11), loosening of the tibial (n = 3) and loosening of the femoral component (n = 2) were identified as the leading causes of pain after TKA.Patients with externally rotated tibial trays showed higher tracer uptake in the medial patellar facet (p = 0.049) and in the femur (p = 0.051). Patients with knee pain due to patellofemoral OA showed significantly higher tracer uptake in the patella than others (p < 0.001).ConclusionsSPECT/CT was very helpful in establishing the diagnosis and guiding subsequent management in patients with painful knees after TKA, particularly in patients with patellofemoral problems and malpositioned or loose TKA.

Combined single-photon emission computerized tomography and conventional computerized tomography (SPECT/CT): clinical value for the knee surgeons?

Single-photon emission computerized tomography in combination with conventional computer tomography (SPECT/CT) is an emerging technology that may hold great clinical value to the orthopaedic knee surgeon. Post-operative knee pain is a familiar condition seen in most orthopaedic clinics. Here, we present the value of SPECT/CT in three such cases of pain after surgical treatment of knee osteoarthritis (high tibial osteotomy, medial unicompartmental arthroplasty, total knee arthroplasty). In these patients with post-operative knee pain, SPECT/CT has proved to be beneficial in establishing the diagnosis and providing guidance for further treatment.

Lengthening osteotomy of the fibula for post-traumatic malunion: Indications, technique and results

Summary.Relative shortening of the fibula may occur after any type of ankle fracture when the lateral malleolus is involved. Patients complain of pain and restriction of their daily and sporting activities. Clinically, there is valgus of the hind foot due to abduction and lateral rotation of the talus. The goal of treatment is to restore the initial length of the fibula by a horizontal or Z-osteotomy, which will also correct the malposition of the talus. This study shows that the operative reconstruction of a widened mortise is a relatively safe procedure, independent of the type of osteotomy used. Lengthening of the fibula is an important step in the treatment of the painful ankle when the fibula is short after trauma, even when degenerative changes of the joint are already present.Resumé.Nous avons analysé six cas de raccourcissement posttraumatique du péroné. Differents types de fracture et de traitement ont menés à cette situation, qui, cliniquement se caracterise par des douleurs au niveau de la cheville et une déviation en valgus et rotation externe du pied. Tous les péronés ont été corrigés par des osteotomies d’allongement (ORP), soit horizontalement ou en forme de ”z”. Nos résultats montrent que la réconstruction opératoire d’une mortaise élargie constitute une intervention relativement simple qui donne de bon résultats et qui peu ralentir ou même arrêter la progression d’une arthrose posttraumatique. En conséquence l’ORP devrait constituer le traitement de choix dans les cas de raccourcissement posttraumatique même si des signes de dégénerescence arthrosique sont présents.

Clinical and radiological outcomes after management of traumatic knee dislocation by open single stage complete reconstruction/repair

BackgroundThe purpose of our study was to analyze the clinical and radiological long-term outcomes of surgically treated traumatic knee dislocations and determine prognostic factors for outcome.MethodsRetrospective consecutive series of patients treated surgically for traumatic knee dislocation with reconstruction/refixation of the anterior (ACL) and posterior cruciate ligaments (PCL) and primary complete repair of collaterals and posteromedial and posteromedial corner structures. 68 patients were evaluated clinically (IKDC score, SF36 health survey, Lysholm score, Knee Society score, Tegner score, visual analogue scale - VAS pain and satisfaction, Cooper test) and radiologically (weight bearing and stress radiographs) with a mean follow up of 12 ± 8 years. Instrumented anterior-posterior translation was measured (Rolimeter, KT-1000). Pearson correlation and stepwise regression analysis was used.Results82% of patients (n = 56) returned to their previous work. At final follow-up 6 patients (9%) suffered from pain VAS > 3. The mean side-to-side difference of anterior/posterior translation (KT-1000, 134N) was 1.6 ± 1.6 mm and 2.6 ± 1.4 mm. Valgus and varus stress testing in 30° flexion was <3 mm (normal) in 57 patients (86%). The IKDC score was normal/nearly normal in 38 (58%) patients and the mean Lysholm score 83 ± 17 (intact 98 ± 7). The median Tegner score decreased from 7 preinjury (range 3-10) to 5 at follow-up (range 0-10). The mean Knee Society score was 187 ± 15 (out of maximum 200). In 7 patients (10%) a secondary ligament reconstruction was performed. Three patients (4%) underwent a high tibial osteotomy and four (6%) received a primary unconstrained total knee replacement. According to the Kellgren Lawrence osteoarthritis score only mild degenerative changes were present. The stress radiographs showed stable results for anteroposterior translation. Injury of the lateral collateral ligament, refixation of the ACL/PCL and delayed surgery >40 days were significantly associated with worse outcome (p < 0.05).ConclusionsEarly complete reconstruction can achieve good functional results and patient satisfaction with overall restoration of sports and working capacity. Negative predictive factors for outcome were injury pattern, type of surgical procedure and timing of surgery.

Combined single photon emission computerised tomography and conventional computerised tomography (SPECT/CT) in patellofemoral disorders: a clinical review

Patellofemoral disorders are common conditions seen in a knee clinic but can present a great diagnostic challenge to the orthopaedic surgeon. Combined single photon emission computerised tomography with conventional computer tomography (SPECT/CT) provides the clinician with precise anatomical and physiological information of the patellofemoral joint. We present a clinical review that highlights the value of SPECT/CT in patients with patellofemoral disorders, where other modalities such as radiographs, MRI, and conventional CT did not provide sufficient information. SPECT/CT has proven to be helpful for establishing the diagnosis and guidance for further treatment. SPECT/CT should be recognised as a valuable diagnostic tool in orthopaedic patients.