Unicondylar Knee Arthroplasty Patients Research Articles

Clinical efficacy of intraarticular vancomycin in preventing early periprosthetic joint infection after primary knee arthroplasty

Objective: To investigate the clinical effect of intraarticular vancomycin on early periprosthetic joint infection (PJI) in knee arthroplasty and the incidence of postoperative complications. Methods: This is a retrospective cohort study. The clinical data of 1 867 patients who underwent primary knee arthroplasty at Department of Joint Surgery, the Affiliated Hospital of Qingdao University from April 2022 to June 2023 were retrospectively analysed, including total knee arthroplasty (TKA), robotic-assisted total knee arthroplasty (RA-TKA) and unicondylar knee arthroplasty (UKA). There were 687 males and 1180 females, aged (68.0±11.2)years(range:45 to 87 years). Patients were divided into the vancomycin group and the control group according to whether or not intra-articular injection of 1 g of vancomycin powder dissolved in 30 ml of saline was performed after intraoperative joint capsule closure. In the vancomycin group, 925 patients were included, including 782 TKA, 27 RA-TKA and 116 UKA.In the control group, 942 patients were included, including 767 TKA, 99 RA-TKA and 76 UKA. Early PJI, wound complications, and vancomycin-related toxicity including acute renal collapse, ototoxicity, and allergic reactions were assessed within 3 months postoperatively. Results: No PJI was found in all patients in the vancomycin group.Five cases (0.7%,5/767) of early PJI were found in TKA patients in the control group, with a statistically significant difference (P=0.030); 1 case of early PJI was found in each RA-TKA and UKA patients, with non-significant difference compared with vancomycin group (all P>0.05). Two cases (0.3%,2/782) of incisional complications were found in TKA patients in the vancomycin group, and 4 cases (0.5%, 4/767) of incisional complications were found in TKA patients in the control group, with non-significant difference(P=0.449); no incisional complications were found in RA-TKA patients in the vancomycin group, and 1 case (1.0%,1/99) of incisional complications were found in RA-TKA patients in the control group, the difference was not statistically significant (P>0.05); no incisional complications were found in both groups of UKA patients.No vancomycin-related acute kidney injury, ototoxicity, or allergic reactions was observed in all patients. Conclusion: Intra-articular injection of 1 g of vancomycin suspension after arthrotomy closure during TKA maybe lower the risk of early PJI without increasing the risk of wound complication and vancomycin-associated systemic toxicity.

A preliminary study on analysis of lower limb energy during walking in the patients with knee replacement

BackgroundKnee replacement surgeries are used to reduce pain and enhance functionality for individuals with knee arthritis. It is predicted that the annual volume of total knee replacement surgeries conducted in the US will surge by a substantial 673% by 2030. Though a lot of studies have done gait analysis on patients with knee replacement, little research is on energy changes in the lower limbs during gait. This study aimed to investigate the mechanical energy changes in the lower limbs for patients with total knee arthroplasty (TKA) and unicondylar knee arthroplasty (UKA), and ultimately to provide a specific tool to analyze limb energy during gait in clinical practice. Methods10 TKA and 8 UKA patients were recruited for gait analysis. The control group consisted of 11 individuals without knee replacement surgery. Vicon motion capture system and Plug-in-Gait model were used to collect gait data to obtain marker coordinates and gait parameters. The kinetic energy, potential energy, and rotational energy for each segment in the lower limbs were calculated. The energies in the centre of pelvis were considered as the approximate to the centre of mass. The energy recovery coefficients were analysed for each segment during gait. SPSS was used to identify the differences between different groups. ResultsThe results showed that during walking, the upper leg had the highest recovery coefficient, approximately 40%, followed by the foot at 10%, and the lowest recovery coefficient was observed in the lower leg, approximately 1–3%. However, the energy recovery coefficients at the centre of pelvis were significantly higher in the control group than the TKA and UKA groups by roughly 12%–15%. ConclusionsThe energy difference between the operative and non-operative sides is not significant regardless of the type of surgery. The TKA and UKA groups were more active in potential energy than control group. The upper leg has the highest recovery efficiency of kinetic and potential energy exchanges when walking. The control group used the energy for whole body is better than the patient groups. This study provides a new and useful way to analyze mechanical energy in the lower limbs during gait and could be applied in clinical practice.

C-Reactive Protein and Erythrocyte Sedimentation Rates after Total and Unicompartmental Knee Arthroplasty-Less Implant Equals Quicker Normalization.

Postoperative follow up after total or unicondylar knee arthroplasty (UKA) includes C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) to scan for and possibly diagnose a periprosthetic joint infection (PJI). The aim of this study was to describe the postoperative changes in CRP and ESR values after UKA and compare them with values obtained after TKA. Patients operated on between 2020 and 2022 were eligible for this retrospective study. Inclusion criteria were patients with at least 4 postoperative visits associated with blood test screening for PJI, aged > 45, with uneventful follow-up for the first 90 days. Exclusion criteria were a history of chronic inflammatory disease, revision for any reason, and readmission for any reason. Blood samples were collected on the 3rd, 15th, and 30th postoperative days and once between the 45th and the 90th day. The mean and peak values were compared between the two groups. The study included 277 patients (243 TKAs and 34 UKAs). Mean age was significantly lower in the UKA group (67.2 ± 7.5 vs. 60.0 ± 5.9). On the 3rd and the 15th postoperative day, the UKA patients had significantly lower ESR and CRP levels. The levels normalized after the first month. While the TKA patients showed higher values, the trend normalized after the 30th day. CRP and ESR values rose significantly after TKA and persisted up to the 15th day postoperatively. CRP and ESR values normalized faster in patients undergoing UKA. Patients > 65 had higher CRP and ESR values during their routine follow-ups.

Assessment of Patient Satisfaction and Outcomes After Outpatient Joint Arthroplasty in Academic Medical Centers

BackgroundThere is limited literature evaluating patient satisfaction and outcomes after outpatient joint arthroplasty procedures in academic medical centers (AMCs). The aims of this study are to determine: (1) patients' desires to repeat their procedures and be discharged on the same day, (2) patient-reported outcome measures (PROMs), (3) time to discharge, (4) readmission rates, and (5) factors that predict PROMs in patients undergoing outpatient joint arthroplasty in AMCs. MethodsA prospective survey was completed by 66 total hip arthroplasty (THA), 35 total knee arthroplasty (TKA), and 180 unicondylar knee arthroplasty (UKA) outpatients who underwent surgery from May 2018 to December 2020 in 2 AMCs. The survey consisted of questions regarding hip or knee PROMs (Hip Disability and Osteoarthritis Outcome Score for Joint Replacement, and Knee Injury and Osteoarthritis Outcome Score for Joint Replacement), satisfaction with outpatient procedures and discharges, and reasons for readmissions. Linear regression analysis was conducted with statistical significance set at P < .05. Results100% of THA, 93.8% of TKA, and 93.0% of UKA outpatients stated that they would re-elect to undergo their respective procedure. Furthermore, 94% of THA, 81% of TKA, and 95% of UKA patients stated they would like same-day discharge again. THA, TKA, and UKA patients reported respective mean PROM scores of 94.7, 89.9, and 86.1. Readmission rates were 1.5%, 0.0%, and 0.5%, for THA, TKA, and UKA, respectively. ConclusionsPatients who underwent outpatient joint arthroplasty procedures at 2 AMCs experienced minimal readmissions and reported a high desire to repeat their outpatient procedures.

COMPARISON OF CHANGES IN THE ANKLE AFTER UNICONDYLAR KNEE ARTHROPLASTY AND HIGH TIBIAL OSTEOTOMY.

ABSTRACTObjectives:We aimed to compare the changes in the coronal alignment of the ankle joints and their clinical effects after high tibial osteotomy (HTO) and unicondylar knee arthroplasty (UKA).Methods:50 HTO and 54 UKA patients who were operated on for medial knee osteoarthritis between 2013 and 2018 were retrospectively evaluated. The hip-knee-ankle angle (HKA), the medial proximal tibial angle (MPTA), the tibial plafond inclination (TPI) and the talar inclination (TI) angles were measured before and after operation. Visual analog scale (VAS), short form 36 (SF-36), and ankle-hindfoot scale (AHS) scores of both groups were evaluated and recorded.Results:Angular changes in the HKA, MPTA, TPI and TI values showed significantly greater values in the HTO group (p<0.001). When asymptomatic and symptomatic cases were compared, it was found that changes in the HKA, TPI and TI values were significantly greater in symptomatic cases in the HTO group (p<0.05). A significant decline was observed in the VAS, SF-36 and AHS scores in the HTO group in the postoperative period (p<0.05). In intergroup evaluations, a significant decline was detected in pain and functional scores of the HTO group when compared to the UKA group (p<0.05).Conclusion:Unicondylar knee arthroplasty can be a good alternative to HTO in selected cases for postoperative ankle complaints. Level of Evidence III; Therapeutic Studies Investigating the Results of Treatment.

Medial unicondylar knee arthroplasty should be reserved for patients with complete joint space collapse

PurposeTo determine whether preoperative radiologic joint space width (JSW) is related to the outcome of medial unicondylar knee arthroplasty (UKA) (primary hypothesis).MethodsA retrospective comparative analysis was performed. One group was comprised of UKA patients with preoperative JSW 0–1 mm. Another group was made up of patients with preoperative JSW ≥ 2 mm (range 0–4 mm). The JSW was measured from preoperative weight-bearing Schuss-view radiographs. The clinical outcome was determined with the Western Ontario and MacMaster Universities (WOMAC) Osteoarthritis Index score preoperatively and 1 year after medial UKA. Implant survival data were obtained from the arthroplasty register of Tyrol.ResultsThere were 80 patients with a preoperative JSW 0–1 mm (age 66, BMI 27.8) and 70 patients with a preoperative JSW ≥ 2 mm (age 64, IQR 15, BMI 28.1). WOMAC total was 10 ± 10 in patients with 0–1 mm JSW and 25 ± 47 in patients with ≥ 2 mm JSW at 1 year postoperative (p = 0.052). WOMAC pain at 1 year postoperative was 7 ± 16 in patients with 0–1 mm JSW and 18 ± 46 in patients with ≥ 2 mm JSW (p = 0.047). WOMAC function at 1 year postoperative was 10 ± 9 in patients with 0–1 mm JSW and 17 ± 51 in patients with ≥ 2 mm JSW (p = 0.048). In patients with 0–1 mm JSW 5 year prosthesis survival was 92.3% and in patients with ≥ 2 mm JSW, it was 81.1% (p = 0.016).ConclusionsIn patients with preoperative complete joint space collapse (0–1 mm JSW), clinical outcome was superior to that of patients with incomplete joint space collapse. This was true for both 1 year postoperative WOMAC pain and WOMAC function and for 5 year implant survival rates. On the basis of our findings, it is recommended that ‘complete joint space collapse’ especially be used to achieve best clinical outcome in medial UKA surgery.Level of evidenceIV.

My kinematics as a template to decode your actions: the role of motor resonance in intention prediction

The aim of the present study is to compare sagittal gait kinematics of ankle, knee and hip joints between subjects with unicondylar and total knee arthroplasty and age matched healthy controls. Since unicondylar knee replacement is a less invasive procedure, which more closely preserves knee joint anatomy, we hypothesized that one year post unicondylar knee arthroplasty patients would demonstrate more normal gait patterns than patients with total knee arthroplasty.Do unicondylar and total knee arthroplasty patients display similar gait kinematics one year after surgery?Fourteen subjects (8 posterior stabilized and 6 medial unicondylar knee replacements) that were one year post surgery, and 6 healthy control subjects underwent a 3D gait analysis and a physical examination (range of motion, muscle strength). Statistical parametric mapping was used to compare gait kinematics of the lower limbs between groups. Additionally, differences in peak angles and clinical outcomes were assessed using a one-way ANOVA between subjects analysis.Both knee replacement groups showed reduced knee flexion range of motion and reduced muscle strength at the operated leg compared to the control group. Subjects with TKA demonstrated reduced knee flexion at loading response and midstance of the gait cycle. Both UKA and TKA demonstrated significantly less knee flexion during swing.The results of this study demonstrate arthroplasty-specific differences in muscle strength, range of motion and gait kinematics of the lower limb one year after knee surgery. Future planning of post-surgery follow-up should addresses these arthroplasty-specific weaknesses and gait deviations.

Lower extremity gait kinematics outcomes after knee replacement demonstrate arthroplasty-specific differences between unicondylar and total knee arthroplasty: A pilot study

BackgroundThe aim of the present study is to compare sagittal gait kinematics of ankle, knee and hip joints between subjects with unicondylar and total knee arthroplasty and age matched healthy controls. Since unicondylar knee replacement is a less invasive procedure, which more closely preserves knee joint anatomy, we hypothesized that one year post unicondylar knee arthroplasty patients would demonstrate more normal gait patterns than patients with total knee arthroplasty. Research questionDo unicondylar and total knee arthroplasty patients display similar gait kinematics one year after surgery? MethodsFourteen subjects (8 posterior stabilized and 6 medial unicondylar knee replacements) that were one year post surgery, and 6 healthy control subjects underwent a 3D gait analysis and a physical examination (range of motion, muscle strength). Statistical parametric mapping was used to compare gait kinematics of the lower limbs between groups. Additionally, differences in peak angles and clinical outcomes were assessed using a one-way ANOVA between subjects analysis. ResultsBoth knee replacement groups showed reduced knee flexion range of motion and reduced muscle strength at the operated leg compared to the control group. Subjects with TKA demonstrated reduced knee flexion at loading response and midstance of the gait cycle. Both UKA and TKA demonstrated significantly less knee flexion during swing. SignificanceThe results of this study demonstrate arthroplasty-specific differences in muscle strength, range of motion and gait kinematics of the lower limb one year after knee surgery. Future planning of post-surgery follow-up should addresses these arthroplasty-specific weaknesses and gait deviations.

Comparison of gait kinematics in total and unicondylar knee replacement surgery

This study is aimed to compare kinematic gait data of patients who have undergone total and unicondylar knee replacement. This single-surgeon retrospective cohort study evaluated 13 patients with unilateral total knee arthroplasty (TKA) and 14 unicondylar knee arthroplasty (UKA). Gait analysis was carried out using a Vicon motion analysis system. The limits of knee flexion during stance phase, at heel strike and at loading response were measured. The total range of motion of the UKA knees was significantly greater than the TKA knees. UKA knees exhibited significantly greater knee extension during the stance phase than the TKA knees. Unlike TKA, UKA knees demonstrated improved knee flexion during the gait cycle when compared to the contralateral non-operated knee. The hips also demonstrated near normal hip flexion in UKA patients. Predictably, UKA knees had significantly greater varus compared with TKA in the coronal plane. Spatiotemporal variables demonstrated similar walking speed and step length to aid a fair comparison between knee replacement groups. The UKA knees moved more physiologically in the sagittal plane with a greater range of motion during gait. Despite having a stiff gait pattern, the patients undergoing TKA demonstrated a more neutral alignment in the coronal plane. Neither type of knee arthroplasty restored knee kinematics to those of the non-operated side.

Does hamstrings co-contraction constrain knee internal rotation in patients with knee endoprosthesis during decline slope walking?

BackgroundMedial and lateral hamstrings are known for their capacity to promote internal or external rotation of the knee. Apart from implant geometry, increased co-contraction to a larger share of either the medial or lateral hamstrings has the potential to contribute to the restricted knee internal rotation especially under consideration of cruciate ligament substituting compared to cruciate ligament retaining knee endoprosthesis designs. Hence, the purpose of the study was to evaluate, whether increased co-contraction of the hamstrings contribute to the impaired knee internal rotation in total and unicondylar knee arthroplasty patients during level and decline walking. MethodsKnee joint angles were calculated using an inverse kinematics model in Anybody. Muscle activity was examined of the semitendinosus and biceps femoris. FindingsKnee internal rotation was constraint in the operated compared to the non-operated limb only in the total knee arthroplasty group during decline slope walking. Co-contraction values revealed no statistically significant differences between the operated and non-operated limb during the limited knee internal rotation period of time (59–94% of stance). Biceps femoris activity was significantly reduced (69–71% of stance) in the operated limb in the total knee arthroplasty group during decline slope walking. InterpretationContrary to the proposed mechanism, aspects other than co-contraction between semitendinosus and biceps femoris are involved in the impaired transverse plane knee motion. These include implant congruency and probably friction. Unexpectedly, the biceps femoris did not compensate the absence of the anterior cruciate ligament with increased muscular activity in the operated limb of the total knee arthroplasty group.

Goal Setting and Achievement in Individualized Rehabilitation of Younger Total and Unicondylar Knee Arthroplasty Patients: A Cohort Study

ObjectiveTo investigate activity goals, intensity and achievement of these activity goals in younger knee arthroplasty (KA) patients, and to identify the differences between total knee arthroplasty (TKA) and unicondylar knee arthroplasty (UKA) patients. DesignProspective cohort study. SettingDepartment of orthopedic surgery and physical therapy practices. ParticipantsPatients (N=48) aged 65 years or younger who underwent KA. InterventionRehabilitation with goal attainment scaling (GAS). Main Outcome MeasuresGAS goals for daily life activity, work and leisure time, corresponding metabolic equivalent of task (MET) values, corrected MET values, and GAS scores at 3 and 6 months. ResultsThe intensity levels of all 144 formulated activity goals were light in 16% of cases, moderate in 63%, and vigorous in 21%. Intensity levels did not differ between TKA and UKA patients. Following rehabilitation using GAS, 54% of daily life activity goals, 65% of work activity goals, and 46% of leisure time activity goals were attained after 3 months. After 6 months, 91% of daily life activity goals, 93% of work activity goals, and 89% of leisure time activity goals were attained. Goal attainment did not differ between MET intensity levels. Higher goal attainment was achieved in the UKA group (100%) compared with the TKA patients (82%) after 6 months (P<.001). ConclusionsYounger patients aim to perform many different activities of varying metabolic intensity levels following KA. After 6 months of rehabilitation using GAS, in these patients attain 91% of their preoperatively formulated activity goals, independent of the MET intensity level. After 6 months, UKA patients attain significantly more activity goals than TKA patients. GAS might be a useful objective outcome measure in evaluating clinical outcomes of individual KA patients.

Compromised knee internal rotation in total knee arthroplasty patients during stair climbing.

Due to the significant role of rotational properties for normal knee function, this study aimed to investigate transverse plane kinematics and kinetics in total knee arthroplasty and unicondylar knee arthroplasty patients during activities of daily living compared to a healthy control group, including stair ascent and descent. The study participants consisted of a total knee arthroplasty group including posterior cruciate retaining and posterior stabilized designs as well as a unicondylar knee arthroplasty group and a healthy control group. Three-dimensional kinematics and kinetics were captured using a Vicon system and two Kistler force plates embedded in the floor and another two in a staircase. Inverse dynamics of the lower limbs was computed in Anybody™ Modeling System. Transverse plane joint angles and joint moments were analyzed utilizing the statistical non-parametric mapping approach, considering the entire curve shape for statistical analysis. The patients with total knee arthroplasty exhibited significantly reduced knee internal rotation of the operated knee compared to the control group and the patients’ unimpaired limb, especially during the stair climbing tasks. Both unicondylar and total knee arthroplasty patients were found to have similar reduced internal rotation motion time series in stair descent. In conclusion, potential kinematic and kinetic benefits of unicondylar knee arthroplasty over total knee arthroplasty could not be proven in the current study. Aside from the usually mentioned reasons inducing constrained knee internal rotation in total knee arthroplasty patients, future studies should investigate to what extent co-contraction may contribute to this functional impairment in patients after knee arthroplasty surgery.

Changes in Markers of Thrombin Generation and Interleukin-6 During Unicondylar Knee and Total Knee Arthroplasty

BackgroundTotal knee arthroplasty (TKA) is associated with a risk of thromboembolism requiring routine thromboprophylaxis, but there is debate about the risk with unicondylar knee arthroplasty (UKA) as it is a more minor procedure. We sought to investigate the relative risk of thromboembolism with UKA compared to TKA and one-staged bilateral TKA (BTKA) by measuring the increase in circulating biochemical markers of thrombin generation during the procedures. Degree of surgical trauma was also assessed by measuring interleukin-6, a marker of metabolic injury. MethodsWe prospectively studied a total of 75 patients: 25 patients undergoing UKA, unilateral TKA, and BTKA, respectively. All patients had surgery performed with tourniquet and received no tranexamic acid. Blood samples were taken during surgery and assayed for circulating markers of thrombin generation: prothrombin fragment 1+2 (F1+2) and thrombin-antithrombin complexes plus interleukin-6. ResultsThrombin-antithrombin complexes, increased during all time points (P < .001) but was not significantly different between surgical treatment groups. F1+2 also rose significantly during surgery, with no significant difference between UKA and TKA. There was, however, a significant difference in F1+2 between BTKA and UKA or TKA (P < .02). Interleukin-6 rose minimally with UKA but rose significantly with TKA and BTKA (P < .001). ConclusionBased on these data of circulating biochemical markers, patients undergoing UKA are at similar risk of thromboembolism with respect to TKA despite a lower index of metabolic injury. We believe that UKA patients should receive thromboprophylaxis comparable to TKA patients.

Outcome of Unicondylar Knee Arthroplasty vs Total Knee Arthroplasty for Early Medial Compartment Arthritis: A Randomized Study

BackgroundWith increasing number of patients with early osteoarthritis of knee opting for total knee arthroplasty (TKA), there has been increase in patients dissatisfied with surgical outcomes. It is being presumed that offering unicondylar knee arthroplasty (UKA) to them would improve outcomes. MethodsPrimary objective of our study was to look for any difference in patient-reported outcome and function at 2-year follow-up in patients undergoing UKA as compared to TKA. Our study was a randomized study with parallel assignment conducted at a high-volume specialized arthroplasty center. Eighty patients with bilateral isolated medial compartment knee arthritis were randomized into simultaneous 2-team bilateral TKA (n = 40) and UKA (n = 40) group. We finally analyzed 36 patients in each group. Main outcome measure was improvement in Knee Outcome Survey-Activities of Daily Living Scale (KOS-ADLS) and High Activity Arthroplasty Score (HAAS) obtained at 2-year follow-up. ResultsImprovement in KOS-ADLS and HAAS at 2 years was similar (P = .2143 and .2010) in both groups. Performance as assessed with Delaware index was also similar. Length of hospital stay was less in UKA group (6.6 days as against 5.4 days). Complications and readmission rates were more in TKA group (nil in UKA group; 08 in TKA group). ConclusionAt 2-year follow-up, UKA provides similar improvement in patient-reported outcomes, function, and performance as compared to TKA when performed in patients with early arthritis. However, UKA patients have shorter hospital stay and fewer complications.

Return to Sports and Physical Activity After Total and Unicondylar Knee Arthroplasty: A Systematic Review and Meta-Analysis.

BackgroundPeople today are living longer and want to remain active. While obesity is becoming an epidemic, the number of patients suffering from osteoarthritis (OA) is expected to grow exponentially in the coming decades. Patients with OA of the knee are progressively being restricted in their activities. Since a knee arthroplasty (KA) is a well accepted, cost-effective intervention to relieve pain, restore function and improve health-related quality of life, indications are expanding to younger and more active patients. However, evidence concerning return to sports (RTS) and physical activity (PA) after KA is sparse.ObjectivesOur aim was to systematically summarise the available literature concerning the extent to which patients can RTS and be physically active after total (TKA) and unicondylar knee arthroplasty (UKA), as well as the time it takes.MethodsPRISMA guidelines were followed and our study protocol was published online at PROSPERO under registration number CRD42014009370. Based on the keywords (and synonyms of) ‘arthroplasty’, ‘sports’ and ‘recovery of function’, the databases MEDLINE, Embase and SPORTDiscus up to January 5, 2015 were searched. Articles concerning TKA or UKA patients who recovered their sporting capacity, or intended to, were included and were rated by outcomes of our interest. Methodological quality was assessed using Quality in Prognosis Studies (QUIPS) and data extraction was performed using a standardised extraction form, both conducted by two independent investigators.ResultsOut of 1115 hits, 18 original studies were included. According to QUIPS, three studies had a low risk of bias. Overall RTS varied from 36 to 89 % after TKA and from 75 to >100 % after UKA. The meta-analysis revealed that participation in sports seems more likely after UKA than after TKA, with mean numbers of sports per patient postoperatively of 1.1–4.6 after UKA and 0.2–1.0 after TKA. PA level was higher after UKA than after TKA, but a trend towards lower-impact sports was shown after both TKA and UKA. Mean time to RTS after TKA and UKA was 13 and 12 weeks, respectively, concerning low-impact types of sports in more than 90 % of cases.ConclusionsLow- and higher-impact sports after both TKA and UKA are possible, but it is clear that more patients RTS (including higher-impact types of sports) after UKA than after TKA. However, the overall quality of included studies was limited, mainly because confounding factors were inadequately taken into account in most studies.Electronic supplementary materialThe online version of this article (doi:10.1007/s40279-015-0421-9) contains supplementary material, which is available to authorized users.

Clinical and functional results after the rehabilitation period in minimally-invasive unicondylar knee arthroplasty patients.

The objective of the present study was to analyze the clinical and functional outcome after minimally-invasive implantation of a Repicci-type unicompartmental sledge prosthesis . In 29 patients with primary unicompartmental knee osteoarthritis, 29 replacements of the medial compartment and four of the lateral compartment were performed using the minimally-invasive technique with the metal-backed and the all-polyethylene versions of the Repicci sledge prosthesis. Electromyography (EMG) of standardized locations was measured with the MyoSystem 2000 and analyzed with Myoresearch software. Gait analysis was performed with a six-camera motion analysis system and force platforms. Established clinical and quality of life (SF-36) scores were used to compare patients with 11 healthy age-matched individuals. The Repicci sledge prosthesis led postoperatively to functional results that were in the range of healthy joints, and superior to sledge prostheses of a different design. Gait and balance parameters were comparable to the control group, whilst electromyographically lower amplitudes were found in the patients than the controls and in the operated legs as compared to the non-operated legs. Many parameters of quality of life and activity were comparable to age-matched healthy individuals, and quality of life was superior to total knee replacement. When implanted using a minimally-invasive technique and with suitable patient selection, the Repicci sledge led to functional results comparable to those of healthy joints and gait parameters comparable to those of healthy individuals. The level of evidence is Level III, retrospective cohort study.