Background Previous studies analyzing femoral components of TKAs have demonstrated the limited ability of these components to accommodate size variations seen in the patient population, particularly width and femoral offset. Questions/purposes The purpose of this study was to use a large data set of knee CT scans (1) to determine the variations in the distal and posterior femoral geometries and to determine whether there is a correlation between distal condylar offset and posterior femoral offset as a potential parameter for symmetry/asymmetry; and (2) to evaluate what proportion of knees would have a substantial mismatch between the implant's size or shape and the patient's anatomy if a femoral component of a modern standard TKA of symmetric (sTKA) or asymmetric (asTKA) designs were to be used. One of the authors (SZ) is an employee of Conformis Inc (Billerica, MA, USA). One of the authors certifies that he (AS) has received personal fees for consultant teaching, during the study period, in an amount of less than USD 10,000 from Conformis Inc, outside the submitted manuscript. One of the authors certifies that he (WK) has received or may receive research support and royalties, during the study period, in an amount of USD 10,000 to USD 100,000 from Conformis Inc, outside the submitted manuscript. One of the authors certifies that he (FK) has received personal fees and grants, during the study period, in an amount of less than USD 10,000 from Conformis Inc, outside the submitted manuscript. One of the authors certifies that he (JB) has received personal fees for consultant teaching, during the study period, in an amount of less than USD 10,000, from Smith & Nephew (Smith & Nephew GmbH, Hamburg, Germany) and personal fees for consultant teaching in an amount of less than USD 10,000 from Conformis Inc, all outside the submitted manuscript. Clinical Orthopaedics and Related Research® neither advocates nor endorses the use of any treatment, drug, or device. Readers are encouraged to always seek additional information, including FDA approval status, of any drug or device before clinical use. Each author certifies that his or her institution waived approval for the reporting of this investigation and that all investigations were conducted in conformity with ethical principles of research.

PurposeThe primary objective of this study was to quantify the variations of the medial posterior tibial slope (MPTS) and the lateral posterior tibial slope (LPTS), as well as of the medial proximal tibial angle (MPTA), and to determine the fraction of patients for which standard techniques including different alignment techniques would result in alteration of the patient’s individual posterior tibial slope (PTS) and MPTA. Furthermore, it was of interest if a positive correlation between PTS and MPTA or between medial and lateral slope exists. MethodsA retrospective study was performed on CT‐scans of 234 consecutively selected European patients undergoing individual total knee replacement. All measurements were done on three‐dimensional CAD models, which were generated on the basis of individual CT‐scans, including the hip, knee, and ankle center. Measurements included the medial and lateral PTS and the MPTA. PTS was measured as the angle between the patient’s articular surface and a plane perpendicular to the mechanical axis of the tibia in the sagittal plane. MPTA was defined as the angle between the tibial mechanical axis and the proximal articular surface of the tibia in the coronal plane. ResultsAnalysis revealed a wide variation of the MPTS, LPTS, and MPTA among the patients. MPTS and LPTS varied significantly both interindividually and intraindividually. The range of PTS was up to 20° for MPTS (from − 4.3° to 16.8°) and for LPTS (from − 2.9 to 17.2°). The mean intraindividual difference between MPTS and LPTS in the same knee was 2.6° (SD 2.0) with a maximum of 9.5°. MPTA ranged from 79.8 to 92.1° with a mean of 86.6° (SD ± 2.4). Statistical analysis revealed a weak positive correlation between MPTA and MPTS. ConclusionThe study demonstrates a huge interindividual variability in PTS and MPTA as well as significant intraindividual differences in MPTS and LPTS. Therefore, the question arises, whether the use of standard techniques, including fixed PTSs and MPTAs, is sufficient to address every single patient’s individual anatomy. Level of evidenceIII.

Purpose As the correct rotational and sagittal alignment of the tibial tray are of key importance for optimal total knee arthroplasty (TKA) function, the objective of this study was to determine these individual variations in the proximal tibial geometry in terms of posterior tibial slope (PTS) and tibial surface asymmetry by analysing a large dataset of computer tomography (CT) information. Methods A retrospective two‐part review was performed on 15,807 datasets that were generated during the design phase for a customized TKA implant. First, 15807 CAD (computer‐aided‐design) models derived from CT data were used to conduct the analysis on the variation of the PTS. Second, the axial cut of each proximal tibia in a consecutively selected subset of 2202 datasets was used to measure the tibial asymmetry. Results The majority (65.5%) of tibiae had a posterior slope between 5° and 10°, while 26.5% of knees had a slope > 10°. The asymmetry measured as offset between the lateral and medial posterior boundaries was highly variable, with overall an increasing proportion of patients with high asymmetry with increasing tibial ML width. Only 14% of tibiae exhibited symmetric (< 2 mm offset) lateral and medial plateaus, and 22% had an offset > 5 mm. Conclusion This study from an extraordinary large data base reveals that tibial posterior slope and asymmetry of the tibial profile vary largely between patients receiving TKA with increasing tibial asymmetry with ML width. CT scans might help to preoperatively better select the best fitting TKA, otherwise surgeons intraoperatively will often have to deal with compromises regarding fitting, sizing and rotational issues. Level of evidence Retrospective case series, Level IV.

In the present study the analgetic effect of ESWT after repeated low-energy application was described for the standard indications.

Background: Symptomatic patients with femoroacetabular impingement (FAI) have limitations in daily activities and sports and report the exacerbation of hip pain in deep flexion. Yet, the exact impingement location in deep flexion and the effect of femoral version (FV) are unclear. Purpose: To investigate the acetabular and femoral locations of intra- or extra-articular hip impingement in flexion in patients with FAI with and without femoral retroversion. Study Design: Cross-sectional study; Level of evidence, 3. Methods: An institutional review board–approved retrospective study involving 84 hips (68 participants) was performed. Of these, symptomatic patients (37 hips) with anterior FAI and femoral retroversion (FV <5°) were compared with symptomatic patients (21 hips) with anterior FAI (normal FV) and with a control group (26 asymptomatic hips without FAI and normal FV). All patients were symptomatic, had anterior hip pain, and had positive anterior impingement test findings. Most of the patients had hip/groin pain in maximal flexion or deep flexion or during sports. All 84 hips underwent pelvic computed tomography (CT) to measure FV as well as validated dynamic impingement simulation with patient-specific CT-based 3-dimensional models using the equidistant method. Results: In maximal hip flexion, femoral impingement was located anterior-inferior at 4 o’clock (57%) and 5 o’clock (32%) in patients with femoral retroversion and mostly at 5 o’clock in patients without femoral retroversion (69%) and in asymptomatic controls (76%). Acetabular intra-articular impingement was located anterior-superior (2 o’clock) in all 3 groups. In 125° of flexion, patients with femoral retroversion had a significantly ( P < .001) higher prevalence of anterior extra-articular subspine impingement (54%) and anterior intra-articular impingement (89%) compared with the control group (29% and 62%, respectively). Conclusion: Knowing the exact location of hip impingement in deep flexion has implications for surgical treatment, sports, and physical therapy and confirms previous recommendations: Deep flexion (eg, during squats/lunges) should be avoided in patients with FAI and even more in patients with femoral retroversion. Patients with femoral retroversion may benefit and have less pain when avoiding deep flexion. For these patients, the femoral location of the impingement conflict in flexion was different (anterior-inferior) and distal to the cam deformity compared with the location during the anterior impingement test (anterior-superior). This could be important for preoperative planning and bone resection (cam resection or acetabular rim trimming) during hip arthroscopy or open hip preservation surgery to ensure that the region of impingement is appropriately identified before treatment.

Objectives To compare the prevalence of pre- and postoperative osseous deformities and intra-articular lesions in patients with persistent pain following arthroscopic femoroacetabular impingement (FAI) correction and to identify imaging findings associated with progressive cartilage damage. Methods Retrospective study evaluating patients with hip pain following arthroscopic FAI correction between 2010 and 2018. Pre- and postoperative imaging studies were analyzed independently by two blinded readers for osseous deformities (cam-deformity, hip dysplasia, acetabular overcoverage, femoral torsion) and intra-articular lesions (chondro-labral damage, capsular lesions). Prevalence of osseous deformities and intra-articular lesions was compared with paired t-tests/McNemar tests for continuous/dichotomous data. Association between imaging findings and progressive cartilage damage was assessed with logistic regression. Results Forty-six patients (mean age 29 ± 10 years; 30 female) were included. Postoperatively, 74% (34/46) of patients had any osseous deformity including 48% (22/46) acetabular and femoral deformities. Ninety-six percent (44/46) had an intra-articular lesion ranging from 20% (9/46) for femoral to 65% (30/46) for acetabular cartilage lesions. Prevalence of hip dysplasia increased (2 to 20%, p = 0.01) from pre- to postoperatively while prevalence of cam-deformity decreased (83 to 28%, p < 0.001). Progressive cartilage damage was detected in 37% (17/46) of patients and was associated with extensive preoperative cartilage damage > 2 h, i.e., > 60° (OR 7.72; p = 0.02) and an incremental increase in postoperative alpha angles (OR 1.18; p = 0.04). Conclusion Prevalence of osseous deformities secondary to over- or undercorrrection was high. Extensive preoperative cartilage damage and higher postoperative alpha angles increase the risk for progressive degeneration. Key Points • The majority of patients presented with osseous deformities of the acetabulum or femur (74%) and with intra-articular lesions (96%) on postoperative imaging. • Prevalence of hip dysplasia increased (2 to 20%, p = 0.01) from pre- to postoperatively while prevalence of a cam deformity decreased (83 to 28%, p < 0.001). • Progressive cartilage damage was present in 37% of patients and was associated with extensive preoperative cartilage damage > 2 h (OR 7.72; p = 0.02) and with an incremental increase in postoperative alpha angles (OR 1.18; p = 0.04).

Frequencies of combined abnormalities of femoral version (FV) and acetabular version (AV) and of abnormalities of the McKibbin index are unknown. To investigate the prevalence of combined abnormalities of FV and AV and of abnormalities of the McKibbin index in symptomatic patients with femoroacetabular impingement (FAI), a retrospective, Institutional Review Board (IRB)-approved study of 333 symptomatic patients (384 hips) that were presented with hip pain and FAI was performed. The computed tomography/magnetic resonance imaging based measurement of central AV, cranial AV and FV was compared among five subgroups with distinguished FAI subgroups and patients that underwent a hip preservation surgery. The allocation to each subgroup was based on AP radiographs. Normal AV and FV were 10–25°. The McKibbin index is the sum of central AV and FV. Of patients that underwent a hip preservation surgery, 73% had a normal McKibbin index (20–50°) but 27% had an abnormal McKibbin index. Of all patients, 72% had a normal McKibbin index, but 28% had abnormal McKibbin index. The prevalence of combined abnormalities of FV and AV varied among subgroups: a higher prevalence of decreased central AV combined with decreased FV of patients with acetabular-retroversion group (12%) and overcoverage (11%) was found compared with mixed-type FAI (5%). Normal AV combined with normal FV was present in 41% of patients with cam-type FAI and in 34% of patients with overcoverage. Patients that underwent a hip preservation surgery had normal mean FV (17 ± 11°), central AV (19 ± 7°), cranial AV (16 ± 10°) and McKibbin index (36 ± 14°). Frequency of combined abnormalities of AV and FV differs between subgroups of FAI patients. Aggravated and compensated McKibbin index was prevalent in FAI patients. This has implications for open hip preservation surgery (surgical hip dislocation or femoral derotation osteotomy) or hip arthroscopy or non-operative treatment.

Background: Although debilitating, proximal hamstring tendon avulsion injuries are rare and often overlooked or misdiagnosed. Consequently, delayed diagnosis and surgical treatment may result in poor outcomes. Studies investigating a correlation between postoperative functional outcomes and this delay in surgical treatment or other concomitant factors in large cohorts have not yet been performed to our knowledge. Purpose/Hypothesis: The purpose of this study was to conduct an investigation in a large patient group regarding factors that could influence a patient’s functional outcome after hamstring surgery. We hypothesized that this outcome would significantly correlate to the time between trauma and surgery. Study Design: Case series; Level of evidence, 4. Methods: Patients who received surgical treatment of proximal hamstring tendon avulsion injuries in our institution between the years 2010 and 2020 were asked to complete a validated, injury-specific outcome measurement, the Perth Hamstring Assessment Tool (PHAT; 0-100 points). In addition to calculating these outcomes, we evaluated the association of the obtained results with possible predictive factors such as age, sex, stump retraction shown on magnetic resonance imaging (MRI), and timing and duration of surgery. Results: A total of 226 patients (227 operations) were eligible for the study, and 204 cases of hamstring tendon avulsion injury met our inclusion criteria. The return rate for the PHAT questionnaire was 85.3%. The mean PHAT score revealed good results (79.8 ± 19.1). Irrespective of concomitant factors, the scores of male patients were significantly higher compared with those of female patients (83.8 ± 16.9 vs 75.8 ± 20.6 respectively; P = .004). The mean time to surgery was 5.7 weeks after trauma, and more delayed surgery correlated significantly with lower PHAT scores ( P = .003; r = –0.228). The mean degree of stump retraction on MRI (5 cm) did not significantly influence PHAT scores ( P = .525; r = –0.06). Conclusion: Delay of surgery and female sex were disadvantageous in terms of a good functional outcome measure (PHAT score) after hamstring tendon refixation surgery. By contrast, patient age as well as the retraction of the tendon stump on preoperative MRI did not influence PHAT scores in the present study.