Purpose: To evaluate the adherence rate and the contribution of self-rehabilitation (SR) guided by a mobile application after anterior cruciate ligament reconstruction (ACLR) in combination with physical therapy sessions on early knee function. Methods: This study was a retrospective analysis of prospectively collected data from a single health care facility. All patients who underwent ACLR by a single surgeon from December 2019 to September 2020 were included. Two groups were formed and compared based on use of the mobile app: users (>10 days of use) and nonusers ( 10 days of use). Outcomes included physical examination at 3 and 6 weeks postoperatively. Results: A total of 65 patients were analyzed: 19 in the nonuser group and 46 in the user group. Adherence rate was 91% at 10 days, 71% at 15 days, 62% at 21 days, and 44% at 45 days. At 3 weeks, the user group was 3.86 times [range 1.12 to 13.3] as likely to lock the quadriceps during gait with crutches and was 4.2 times [range 1.2 to 14.3] as likely to be pain free. There was a tendency to have less flexion contracture in the user group (17% versus 32%, P ¼ .32). At 6 weeks, the differences leveled out, but the user group still had slightly better quadriceps locking during gait without crutches (87% versus 79%, P ¼ .46). Conclusions: SR guided by a mobile app combined with a standard rehabilitation protocol is correlated with better knee function at initial follow-up. Level of evidence: IV, therapeutic case series.

Purpose To report the early clinical and radiographic outcomes of custom total knee arthroplasty (TKA) in knees that had prior osteotomies and/or extra-articular fracture sequelae. Methods The authors retrospectively analysed a consecutive series of 444 knees that received custom TKA between 2016 and 2019 and identiied 41 knees that had prior extra-articular events (osteotomies or fracture sequelae). Patients responded to pre-and post-operative (> 12 months) questionnaires, including Knee Society Score (KSS), Oxford Knee Score (OKS), Forgotten Joint Score (FJS) and Knee injury and Osteoarthritis Outcome Score (KOOS). Net improvements were calculated by subtracting pre-from post-operative scores. In addition to a preoperative CT scan, pre-and post-operative long-leg weightbearing radiographs were obtained, on which the hip-knee-ankle (HKA) angle, femoral mechanical angle (FMA, between femoral mechanical axis and joint line) and tibial mechanical angle (TMA, between tibial mechanical axis and joint line) angles were measured, and alignment was planned within a 'target zone' of FMA and TMA within 85°-95° and HKA angle within 175°-183°. Agreements between preoperative, planned and post-operative angles were calculated using intra-class correlation coeicients (ICC). Results From the initial 41 knees, 3 had incomplete post-operative data and 1 was revised for painful stifness due to uncorrected rotational malunion, leaving 37 knees for analysis. Twenty had prior osteotomies (tibia, n = 18, femur, n = 2), 8 had isolated fractures (tibial, n = 3; femoral, n = 5), and 9 had both osteotomies and fractures. Postoperative coronal alignments were 90.4° ± 2.4° for FMA, 89.3° ± 2.6° for TMA and 179.9° ± 3.0° for HKA angle. Agreements between planned and achieved alignments were fair to excellent, and 29 (78%) knees were within the 'target zone'. At a mean follow-up of 15 ± 5 months, all clinical scores had improved signiicantly (p < 0.001). Conclusions Custom TKA granted satisfactory clinical outcomes and a low complication rate in knees that had prior osteotomies and/or extra-articular fracture sequelae. Using custom implants and strategies for coronal alignment, 29 (78%) of the 37 knees were successfully aligned within the 'target zone', and 35 (95%) of the 41 knees did not require ligament release. Level of evidence IV.

Purpose The purpose of this study was to report Knee Society Scores (KSS) at 12-month follow-up in a series of 266 knees that received custom TKA. The hypothesis was that custom TKA combined with personalised alignment would yield improvements greater than substantial clinical beneits (SCB) of KSS Knee and Function. Methods From a consecutive series of 905 patients (918 knees) that received primary TKAs, 261 (29%) patients (266 knees) received computed tomography (CT)-based posterior-stabilised cemented custom TKA. Knees were aligned aiming to preserve or restore constitutional alignment within predetermined limits of 85°-95° for femoral mechanical angle (FMA) and tibial mechanical angle (TMA), and 175°-183° for hip knee ankle (HKA) angle. The KSS Knee and Function were collected preoperatively and 12 months postoperatively, to determine if patients achieved SCB. Uni-and multivariable analyses were performed to determine associations between KSS scores (Knee and Function) and patient demographics as well as pre-and postoperative radiographic alignments. Results Of the initial cohort of 261 patients, 4 (1.8%) were reoperated for patellar resurfacing, 1 (0.4%) for lavage to treat infection, and 1 (0.4%) had arthroscopy to treat a stif knee with < 90° range of motion. Complete clinical records were available for 227 patients (232 knees, 87%) that comprised 102 men (5 bilateral) and 125 women. At 12-month follow-up, mean improvements in KSS Knee and Function scores were, respectively, 61.0 ± 13.0 and 42.7 ± 16.7, which exceeded the SCB of KSS. Comparison of knees inside versus outside the target zone revealed no diferences in KSS Knee (94.1 ± 9.1 versus 94.3 ± 9.0, n.s.) and Function (96.1 ± 9.2 versus 96.3 ± 8.9, n.s.). Multivariable analysis revealed worse KSS Knee in knees with preoperative FMA > 95° (β = − 6.21; p = 0.023), but no association between KSS Function and patient demographics or pre-and postoperative radiographic alignments. Conclusions Custom TKA combined with personalised alignment yielded improvements that exceeded substantial clinical beneits of KSS Knee and Function scores. These indings demonstrate the feasibility of custom TKA with 'personalised alignment' and encourage further investigations using comparative studies at longer follow-up. Level of evidence IV, case series.