Mobile-bearing prosthesis did not improve mid-term clinical results of total knee arthroplasty

A prospective study was performed to compare the clinical and radiological results of mobile- and fixed-bearing total knee arthroplasty with specific attention to rotational alignment and range of motion. Sixty-one knees were assigned to total knee arthroplasty with either the NexGen LPS Flex fixed-bearing or with the NexGen LPS Flex mobile-bearing prosthesis. Postoperatively, knees were compared with regard to range of motion, clinical score, and radiographic findings. Rotational alignment of the femoral and tibial components was evaluated by computed tomography. The median follow-up period was 5.9 years (range 2.1–8.8 years). Median postoperative Knee Society scores were 99 points (68–100) for the fixed-bearing group and 100 points (66–100) for the mobile-bearing group (n.s.). The median postoperative flexion angles of 120° (90°–150°) for the fixed-bearing group and 125° (90°–145°) for the mobile-bearing group were not significantly different from each other (n.s.). No knee required revision surgery due to wear of polyethylene or loosening of the component in either group. Computed tomography showed that 11 knees had rotational mismatches of more than 10° between the femoral and tibial components, but no significant difference was found in the postoperative extension and flexion angles or in the clinical score between the two treatment groups. Using the identical design for both fixed- and mobile-bearing prostheses, this prospective, randomized study did not show any clinical advantages of the mobile-bearing knee. Analysis of rotational alignment by CT scan did not reveal a particular advantage of the self-aligning mechanism of mobile-bearing implants.     

What have we learned from LCS mobile-bearing knee system?

Three hundred and sixty-four low contact stress (LCS) total knee arthroplasties that could be followed up for more than 5 years were clinically and radiographically analyzed. The median postoperative Hospital for Special Surgery score improved from 56 (range 32–77) to 91 (range 64–100) points, but median range of motion did not change from 120° (range 50°–135°) to 120° (range 85°–135°). Complications occurred in 16 cases (4%), and included postoperative polyethylene dislocation and intraoperative tibial condylar fracture, while five knees (1%) required revision surgery due to mechanical reasons. The overall prosthesis survival rate was 91% at 12 years. Although the LCS mobile-bearing knee system has theoretical advantages in terms of wear and loosening, the problem of polyethylene dislocation, intraoperative tibial fracture, and radiolucent lines should be solved for long survival. The clinical relevance of this study is that the LCS system provided good clinical and survival results.     

Staged bilateral mobile-bearing and fixed-bearing total knee arthroplasty in the same patients: a prospective comparison of a posterior-stabilized prosthesis

Mobile-bearing total knee arthroplasty (TKA) has several theoretical advantages over fixed-bearing TKA. We conducted a prospective randomized trial to compare the results of mobile-bearing and fixed-bearing posterior-stabilized TKA in the same patients using the same femoral component design of a mobile-bearing prosthesis in one knee and a fixed-bearing prosthesis in the other knee in 25 patients with osteoarthritis. The mean follow-up was 40 months. No significant differences were found in the mobile-bearing and fixed-bearing knees in terms of clinical and radiographic results. No osteolysis, loosening, or revision occurred. One knee with a mobile-bearing prosthesis had a dislocation of the rotating bearing; however, spontaneous reduction occurred and the dislocation did not recur. Satisfactory early results can be achieved in both mobile-bearing and fixed-bearing knees. We could not demonstrate an advantage of a mobile-bearing TKA.     

High tibial osteotomy in young adults with constitutional tibia vara

Frontal plane malalignment of the lower extremity results in abnormal load distribution across the knee joint. Consequences of this increased stress may lead to compartmental osteoarthritis. High tibial osteotomy is well established for early osteoarthritis of the knee joint in middle-aged patients. We hypothesize that earlier realignment of the varus knee can be performed without undue risks and debilitation toward the young active patient and with good results in short-term follow-up. Open-wedge high tibia osteotomy using the Puddu plate was performed on eleven patients (19 knees) under 25 years of age for constitutional high tibia vara. The mechanical femorotibial angle (FTA) and Knee Society Knee Score (KSKS) were compared pre-operatively and 24 months post-operatively. The average FTA improved from +8.8 degrees (+5 – +16) to −0.1 (−2 – +5). The average KSKS improved from 74 (50–100) to 93 (60–100) and the function score improved from 84 (50–100) to 95 (60–100). Special concerns in this age group include unsightly cosmesis, and kneeling pain and discomfort. Open-wedge high tibia osteotomy provides a satisfactory solution for constitutional high tibia vara with minor morbidity on behalf of the patient in the short-term follow-up period.     

Clinical outcome after reconstruction for isolated posterior cruciate ligament injury

Fifty-one patients were operated with reconstruction for an isolated PCL injury from 1997 to 2005. Forty-three of these patients were followed during a median period of 48 months (17–109). Median time from injury to surgery was 18 months (2–368). Five patients were operated within the first 6 months after the injury. Nineteen patients had a BPTB autograft, 24 had a hamstring tendon autograft, and seven patients in the hamstring group had a double-bundle femoral fixation. Clinical assessment included Lysholm knee score, International Knee Documentation Committee 2000 (IKDC) scores, Cincinnati score, Tegner score, KOOS score, VAS score, stress radiographs, and a functional test. The median Lysholm score at follow-up was 80 (32–95). Median Tegner score before injury was 7 (1–10) and at follow-up 6 (0–9). Median Cincinnati and IKDC 2000 scores were 74 (12–100) and 63 (24–100), respectively. The mean VAS for subjective assessment of knee function was 67.6 (SD = 22.9). The radiologically measured difference in posterior tibial translation between operated and non-injured knees was mean 8.4 mm (SD = 4.8). Four different functional tests showed function of the operated leg from 92% (25–128) to 95% (15–124) compared to the opposite leg. This study shows good functional outcome after reconstruction for isolated rupture of the posterior cruciate ligament. However, pain and instability are still a problem, as only three patients reported full Lysholm subscore indicating full stability, and only four patients reported full subscore indicating no knee pain.     

Combined reconstruction for posterolateral rotatory instability with anterior cruciate ligament injuries of the knee

If posterolateral rotatory instability (PLRI) injury in patients with a torn anterior cruciate ligament (ACL) is not diagnosed and treated, ACL reconstruction can fail. We retrospectively evaluated the clinical outcome after reconstructions between 2002 and 2007 of both the ACL and the posterolateral corner (PLC) in 44 knees with combined ACL and PLC injuries. The median follow-up duration was 49 months (range, 24–68 months). ACL reconstruction employed autogenous hamstring grafts from the ipsilateral knee. For grade II PLRI, a posterolateral corner sling through the fibular head was placed obliquely from the anteroinferior aspect to the posterosuperior aspect using autogenous hamstring grafts of the contralateral knee. Clinical outcomes were evaluated using the OAK (Orthopadishe Arbeitsgruppe Knie) and IKDC (International Knee Documentation Committee) knee scoring systems. Anterior stability was measured on pull stress radiographs using a Telos stress device and the manual maximum displacement test using a KT-1000™ arthrometer with the knee flexed 30 degrees. PLRI was classified according to varus and rotational instability preoperatively and at final follow-up. Median OAK scores improved from 71 points (range, 48–86) to 93 points (range, 75–100). Satisfactory IKDC results were achieved in 39 knees (89%). As for anterior stability, as measured by anterior stress radiography, mean side-to-side displacement difference dropped significantly from 6.9 ± 1.9 preoperatively to 1.4 ± 1.1 mm at final follow-up. Forty patients (91%) had the same or better rotational stability compared to the normal side. Varus stress radiographs showed mean side-to-side displacement differences dropped from 1.8 ± 1.7 preoperatively to 0.4 ± 0.8 mm at final follow-up. Thus, chronic ACL deficiency is often accompanied by grade II PLRI and can be treated successfully by arthroscopic ACL reconstruction paired with posterolateral reconstruction employing a single sling through the fibular tunnel and a hamstring tendon autograft.     

Clinical results of posterior cruciate ligament retaining TKA with alumina ceramic condylar prosthesis: comparison to Co–Cr alloy prosthesis

In a prospective study, 194 knees undergoing total knee arthroplasty (110 knees with alumina ceramic prostheses; 84 knees with Co–Cr alloy prostheses) were clinically and radiologically evaluated. Average follow-up period was 66 months (36–124 months). Average age at the time of surgery was 66 years. In the ceramic prostheses, two revision surgeries were performed because of breakage of the tibial tray and late infection, whereas two revisions of the Co–Cr alloy prostheses were carried out due to loosening and late infection. In the other patients, there were no significant differences in clinical parameters (HSS knee score and range of motion) between the two prostheses. In radiological evaluation, we could not find any radiolucent lines around the femoral ceramic component while radiolucency was present in three knees (3.6%) around the Co–Cr femoral component. Beneath the tibial tray, three knees (2.7%) showed a radiolucent line around the former prosthesis while eight knees (9.5%) demonstrated a radiolucent line around the latter prosthesis. Chi-square tests showed a significant difference in the occurrence of radiolucent line around both of the femoral and tibial prosthesis. This study demonstrated that clinical results of the alumina ceramic PCL retaining total knee prosthesis are comparable to the standard Co–Cr alloy PCL retaining total knee prosthesis. Although we could not draw any conclusions regarding the superiority of the ceramic prosthesis with respect to UHMWPE wear and long-term survivorship, this report encouraged a long-term follow-up study on ceramic prostheses. Presented in part at the meeting of the International Society of Arthroscopy, Knee Surgery, and Orthopaedic Sports Medicine, New Zealand, 2003.     

Surgical treatment of patellar dislocation in children with Down syndrome: a 3- to 11-year follow-up study

We report results of surgical treatment of ten knees affected by patellar dislocation in six children with Down syndrome. Four knees showed a dislocatable patella (grade III according to Dugdale), two a dislocated reducible patella (grade IV) and four a dislocated irreducible patella (grade V). Symptoms included frequent falls, limping and pain. In all the cases a Roux–Goldthwait–Campbell procedure was performed. Mean age at surgery was 10 years (range 6 years and 6 months to 13 years and 4 months). Patients were reviewed at an average follow-up of 8 years and 8 months (range 3 years and 6 months to 11 years and 5 months). None showed signs of recurrence of the dislocation. The median Lysholm score improved from 57.5 to 91/100. Statistical analysis showed a significant effectiveness of the procedure in improving function, and that surgery was significantly more effective in patients with more severe disability.     

The Self-Aligning knee prosthesis: clinical and radiological outcome and survival analysis at 5-year follow up

The purpose of this study is to evaluate the clinical and radiological results and the survival of the SAL II mobile bearing knee prosthesis at 5-year follow up. Between February 1995 and March 1998 a total of 246 SAL II total knee arthroplasties were performed in 232 patients. The mean follow up was 5.0 years. Thirteen revisions had been carried out (5%). The mean total Knee Society Score increased from 88 preoperatively to 153 and 155 at 1 and 5 years follow up, respectively. The mean flexion angles were 106 degrees and 107 degrees pre- and postoperatively. None of the prostheses showed radiological loosening. No dislocations or subluxations of inserts were seen. The Kaplan-Meier cumulative survival is 95% for revision for any reason at 5.0 years, with a worst case scenario of 91%. The survival for aseptic loosening is 99%. The results of SAL II after a minimum follow up of 5 years are favourable and comparable with fixed bearing and other mobile bearing designs in terms of Knee Society Score and survival. Noteworthy are the good radiological results of this device which showed a good fixation of the prosthesis at 5 years.     

Anterior cruciate ligament revision reconstruction: results using a quadriceps tendon-patellar bone autograft

BACKGROUND: The quadriceps tendon is a viable graft source for revision anterior cruciate ligament reconstruction. PURPOSE: To determine the functional results and graft failure rates in knees in which the patellar tendon had been previously harvested or was unavailable, expanded tunnels precluded the use of a semitendinosus-gracilis graft, or patients requested autogenous tissues instead of allografts for revision reconstruction. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: The authors observed 21 patients for a mean of 49 months postoperatively after revision anterior cruciate ligament reconstruction with a quadriceps tendon graft. The results were determined by KT-2000 arthrometer testing, the Cincinnati Knee Rating System, and the International Knee Documentation Committee Rating System. Fifteen knees required a concurrent procedure, including reconstruction of posterolateral structures in 5 knees, meniscal repairs in 5 knees, and high tibial osteotomy in 2 knees. RESULTS: Significant improvements occurred in symptoms (P < .0001), daily activities (P < .05), sports activities (P < .01), and the overall rating scores (P < .0001). Eighteen patients rated their knee condition as improved. Total mean anterior-posterior displacements decreased from 8.4 +/- 3.1 mm preoperatively to 2.0 +/- 2.3 mm at follow-up (P < .001). On the International Knee Documentation Committee knee ligament rating, 17 knees were graded as normal or nearly normal, 3 were graded as abnormal, and 1 was graded as severely abnormal. CONCLUSION: The revision operation provided reasonable results in this group of complex knees. However, the functional and overall results were inferior to those reported for primary anterior cruciate ligament reconstruction. Many knees (90%) had compounding problems of articular cartilage damage, meniscectomy, varus malalignment, or additional ligamentous injury that most likely affected the results.     

Early failure of a mobile-bearing unicompartmental knee replacement

Concerned by a perceived high revision rate, we retrospectively reviewed the survivorship of a series of 43 cemented, medial, mobile-bearing Preservation unicompartmental knee replacements implanted during a 2-year period at a single institution. The initial post-operative AP and lateral radiographs were independently assessed to test the hypothesis that suboptimal implantation of the prosthesis was responsible for early failure. An X-ray scoring system based on the criteria for assessing the Oxford mobile-bearing unicompartmental knee replacement was devised. The components of this score included assessment of prosthesis alignment, sizing and cementation. Nine (21%) LCS Preservation mobile-bearings prostheses had required revision at a mean of 22 months post-implantation. The commonest causes for failure were pain (44%) and tibial component loosening (33%). Analysis of post-operative radiographs showed no difference (n.s.) between the compound error scores for the revised and the surviving prostheses. No particular surgical error was identifiable leading to subsequent need for revision. The high failure rates shown in this study have led us to cease using this implant. The clinical relevance of this study is that the captive running track of the LCS mobile-bearing prosthesis may over constrain the meniscal component leading to early failure.     

Knee function among elite handball and football players 1‐6 years after anterior cruciate ligament injury

The aim of the study was to describe objective and self‐reported knee function for athletes who have returned to elite handball and football play after an ACL injury, comparing these to non‐injured players at the same level. A total of 414 handball and 444 football players completed baseline tests from 2007 through 2014, examining lower extremity strength, dynamic balance, knee laxity, and knee function (KOOS questionnaire). Measures were compared between injured and non‐injured legs and between injured legs and legs of controls. Eighty (9.3%) of the 858 players reported a previous ACL injury, 1‐6 years post‐injury (3.5±2.5 years), 49 handball (61.3%) and 31 football players (38.7%). We found no difference in strength or dynamic balance between previously ACL‐injured (N=80) and non‐injured players legs (N=1556). However, lower quadriceps (6.3%, 95% CI: 3.2‐9.2) and hamstrings muscle strength (6.1%, 95% CI: 3.3‐8.1) were observed in previously ACL‐injured legs compared to the non‐injured contralateral side (N=80). ACL‐injured knees displayed greater joint laxity than the contralateral knee (N=80, 17%, 95% CI: 8‐26) and healthy knees (N=1556, 23%, 95% CI: 14‐33). KOOS scores were significantly lower for injured knees compared to knees of non‐injured players. ACL‐injured players who have successfully returned to elite sport have comparable strength and balance measures as their non‐injured teammates. Subjective perception of knee function is strongly affected by injury history, with clinically relevant lower scores for the KOOS subscores Pain, Function, Sport, and Quality Of Life.     

Clinical features and classification of bipartite or tripartite patella

The purposes of this study were to report clinical features of the developmental anomaly of ossification type bipartite or tripartite patella using a large series and to propose a new classification for the developmental anomaly of ossification type bipartite or tripartite patella. The first author prospectively examined 111 patients with symptomatic or asymptomatic bipartite (131 knees) or tripartite (8 knees) patellae. Eighty-six (77%) were male and 25 (23%) were female. Forty-three patients (39%) showed right knee involvement and 40 (36%) showed left, while 28 (25%) showed involvement in both knees. Forty-six bipartite and 4 tripartite patellae (36%) were symptomatic and 85 bipartite and 4 tripartite patellae (64%) were asymptomatic at initial examination. The median age at onset of pain of symptomatic patients (50 knees) was 15.6 ± 8.1 years (range, 10–51 years). The most common symptom was pain at the separated fragments during or after strenuous activity in all 50 knees. Physical examination revealed localized tenderness over the separated fragments in all 50 knees. Bipartite or tripartite patellae were classified by evaluating location and number of fragments. One hundred fifteen knees (83%) were classified as supero-lateral bipartite type, 16 (12%) were lateral bipartite type, 6 (4%) were supero-lateral and lateral tripartite type, and 2 (1%) were supero-lateral tripartite type. For the developmental anomaly of ossification type bipartite or tripartite patella, a classification based on both location and number of fragments is simple and easy to understand and applicable to all types of bipartite or tripartite patella.     

Increasing financial burden of revision total knee arthroplasty

We reviewed the peri-operative and financial data of patients who underwent revision total knee arthroplasty in our institution between 1997 and 2006. The aims were to compare difference in cost between aseptic and septic cases and to identify the sources of preventable cost increase in revision knee procedure. The study group comprised 117 women (65%) and 62 men (35%). The median age of patients decreased from 73 years (37–83 years) in 1997–2001 to 70 years (15–91 years) in 2002–2006, a decline of 4% (P < 0.05). The mean ASA scores also dropped from 3 to 2 between the two periods. Despite this, the mean total cost of revision knee procedure continued to increase. Patients undergoing revision arthroplasty because of infection had much higher (P = 0.0001) cost compared to their aseptic counterpart. Increase in the costs of investigations (P < 0.05) and implant (P < 0.05) was the major contributing factors. The cost of implants increased by 32–35% (P < 0.05) depending on implant selection. Changing demographics will increase the requirement for this surgery and thus increase its overall cost to society. Cost increases associated with unnecessary investigations, prolonged hospital stay and use of expensive implants should be avoided.     

Arthrodesis of the knee after failed infected total knee arthroplasty

Infection after total knee arthroplasty (TKA) can be a challenging and difficult problem to treat. In selected patients, knee arthrodesis is a well-recognized salvage procedure after infected TKA. The authors retrospectively reviewed their experience with this treatment option, presenting 20 patients (8 women, 12 men), performed between 1990 and 2002. The average age was 67 years (range: 47–81 years) and the mean number of previous surgical procedures was 6 (range: 4–11 procedures). There were multiple indications for knee arthrodesis, including extensive bone or soft tissue loss, poor bone stock, and recurring infections. One-stage fusion was done in 7 knees while, on the other 13, arthrodesis was performed as two-stage fusions. The average clinical follow-up was 4.5 years (range: 2–11 years). 18 of the 20 patients were interviewed and graded using the Visual Analogue Scale (VAS) for pain, the Short Form-36 Health Survey (SF-36), and the Knee injury and Osteoarthritis Outcome Score (KOOS) questionnaire that has knee-related quality of life items. According to the VAS, the mean intensity was 3.4 points. 6 (33%) of the patients had no difficulty with the knee and 9 (50%) of them had mild or moderate difficulty. The SF-36 scores were similar to those for normative data for patients after TKA, with only the social functioning, role emotional, and physical functioning scores being lower and the role physical and social functioning scores being higher. Three of 20 fusions failed, whereas two knees became non-infected non-unions. In one, the knee infection persisted and required above-knee amputation. The two-stage arthrodesis gave the most predictable rate of fusion. Persistent infection and extensive bone stock losses led to failure even under the best circumstances. In our opinion, arthrodesis of the knee is a satisfactory salvage procedure following a failed TKA, and can provide reliable expectation for a stable, painless extremity for high-functioning patients who are able to walk.     

Avoidance of patellar eversion improves range of motion after total knee replacement: a prospective randomized study

Minimally invasive surgery has recently been introduced in TKA surgery. The purpose of this study was to evaluate the effect of eversion of the patella, on safety and functional result after TKA. In a prospective, randomised, double blinded trial, 60 patients were divided in two groups: group A underwent TKA through a standard medial parapatellar arthrotomy, with patellar eversion. Group B underwent the same exposure, except for the fact that the patella was subluxed laterally. All other treatment protocols were identical. Outcomes were measured until 1 year postoperatively. Radiographic evaluation included AP, lateral, skyline and full leg standing radiographs. VAS, WOMAC score, Knee Society Knee and Function score were performed. Active and passive range of motion (ROM) and knee proprioception was measured. All patients underwent isokinetic strength testing. The mean passive ROM changed from 121° preoperatively to 121° postoperatively in group A, compared to 118°–131° respectively in group B at 1 year (P = 0.003). The mean active ROM changed from 112° to 115° in group A, and from 108° to 125° in group B (P = 0.005). All other parameters were not significantly different. Patellar dislocation without eversion for exposing the knee during TKA is a safe procedure and improves ROM at 1 year postoperatively.     

The femoral sulcus in total knee arthroplasty

The position of the femoral sulcus relative to the midline of the distal femoral resection in total knee arthroplasty (TKA) was studied to determine if centralized placement of the femoral component on the distal femur was justified in terms of aligning the prosthetic sulcus with the native femoral sulcus. The location of the femoral sulcus was studied in 112 consecutive patients undergoing TKA. The mean sulcus position was 0.7 mm lateral to the midline of the distal femoral resection (SD 1.4, 95% CI, 0.5–1.0 mm). However, the variation in sulcus positions ranged from 4 mm medial to 4 mm lateral to the midline. The mean sulcus position in valgus knees was 1.0 mm lateral to the midline (SD 1.8), and that in varus knees was 0.7 mm lateral to the midline (SD 1.2) (P = 0.501). It appears prudent to centre the femoral component on the native sulcus rather than the midline of the distal femoral resection, so as to ensure accurate alignment of the prosthetic sulcus with the native sulcus and to encourage normal patella tracking.     

Comparison of the bioabsorbable and metal screw fixation after ACL reconstruction with a hamstring autograft in MRI and clinical outcome: a prospective randomized study

There has never been an MRI study of tunnel widening comparing bioabsorbable to metal screw fixation in autologous hamstring anterior cruciate ligament (ACL) reconstruction. We randomized 62 patients to hamstring ACL reconstruction with either a bioabsorbable (n = 31) or metal screw (n = 31) fixation. The evaluation methods were clinical examination, KT-1000 arthrometric measurement, the International Knee Documentation Committee and Lysholm scores, and MRI. There were no differences between the groups preoperatively. Fifty-five patients (89%) were available at a minimum of 2-year follow-up (range 24–36 months). There was tunnel widening in both groups, but the increase was significantly greater in the AP dimension of the femoral tunnel in the bioabsorbable screw group compared to metal group (P = 0.01). The tibial tunnels showed no intergroup difference. Ninety-four percent of the knees were normal or nearly normal according to the IKDC scores and the average Lysholm score was 91 with no intergroup difference. The follow-up AP tibial tunnel diameter was smaller with normal knee laxity compared to abnormal knee laxity. The graft failure rate in the bioabsorbable screw group was 23% (7/31 patients) and 6% (2/31 patients) in the metal screw group. The use of bioabsorbable screws resulted in more femoral tunnel widening, and more graft failures compared to metal screws. The tunnel widening in the tibia was associated with the knee laxity (P = 0.02).     

The association between component malalignment and post-operative pain following navigation-assisted total knee arthroplasty: results of a cohort/nested case–control study

Previous studies have noted an adverse relationship between implant malalignment during total knee arthroplasty (TKA) and post-operative pain. Although some evidence exists indicating that computer-assisted surgical navigation for TKA can improve the accuracy of component alignment, its impact on clinical outcomes is currently unknown. The dual goals of the present cohort/nested case–control study were to (1) compare self-reported responses to the Western Ontario-McMaster Osteoarthritis Index (WOMAC) questionnaire between computer-assisted TKA (123 patients) using the imageless PiGalileo navigation system and conventional TKA (207 patients) [cohort analysis], and (2) to investigate a potential association between malalignment and post-operative pain in 19 painful knees and 19 asymptomatic knees obtained from the cohort analysis using matched sampling [nested case–control study]. In the cohort analysis, a relevant but non-significant (P = 0.06) difference in the occurrence of chronic pain was observed between the navigated (12%) and conventional arms (20%). Median post-operative WOMAC pain score was 100 (range, 50–100) in the conventional group and 100 (range, 65–100) in the navigated group. However, the Mann–Whitney test revealed a significant difference in favor of the navigated group (P = 0.01). In the nested case–control analysis, radiological outcomes and computer tomography (CT) measurements of femoral rotation were compared between the groups. The CT rotation measurements yielded evidence of a relationship between post-operative pain and incorrect rotational alignment of the femoral component of more than 3° (OR: 7; 95% CI: 1.2–42; P = .033). In conclusion, there was no clinical benefit to computer-assisted navigation; however, a statistically significant relationship was observed between incorrect rotational alignment of the femoral component and symptoms of post-operative pain following TKA.     

Multiple osteochondroses of bilateral knee joints: a case report

Knee injuries in young athletes include not only the typical adult bone injuries, ligament and cartilage, but also the growth plate lesions. Osteochondroses are idiopathic, self-limited disturbance of enchondral ossification in which a rapid growth spurt is present. The patella could be affected by two different kinds of osteochondroses: Kohler syndrome and Sinding–Larsen–Johansson. Here we are reporting the first case of simultaneous location of ostechondroses of the two ossification centers of both patella. A 9-year-old boy, competitive skater, presented a history of anterior knee pain involving both knees. Standard X-rays, axial patellar view, MRI and arthro-MR were performed. In order to follow the natural history of the pathology and the evolution of the healing, examinations at 2 years were repeated. We proposed the young skater a medical and a physiotherapeutic treatment based on unloading, isometric exercises, NSAID. As the symptoms improve a gradual return to competitive sports activity was allowed. The case mentioned above can be considered an atypical case because the patient suffered for a bilateral knee osteochondroses, involving simultaneously the primary ossification centre (Kohler syndrome) and the secondary ossification centre (Larsen syndrome) of the patella.