Effect of accelerated postoperative rehabilitation after tibial tubercle distalisation: A randomised controlled trial protocol.

Patella alta is a clinical condition where the patella is positioned too proximal in relation to the femoral trochlea. Such an abnormality may cause patellar instability and predispose to recurrent patellofemoral dislocations and patellofemoral pain. There are no conclusive guidelines for determining a threshold for too high positioned patella, as several different methods have been described to measure patellar height. As a surgical solution, distalising tibial tubercle osteotomy has been described to correct excessive patellar height. In the early phase of the distalising tibial tubercle osteotomy postoperative protocol, weightbearing and knee flexion are limited with a brace commonly for 4-8 weeks to avoid potential implant failure leading to displacement of the osteotomy or non-union. The potential risks for adverse effects associated with the limitation rehabilitation protocol include a delay in regaining knee range of motion, stiffness and muscle weakness. As a result, recovery from surgery is delayed and may lead to additional procedures and long-term morbidity in knee function. This is a prospective, randomised, controlled, single-blinded, single centre trial comparing a novel accelerated rehabilitation protocol with the traditional, motion restricting rehabilitation protocol. All skeletally mature patients aged 35 years and younger, referred to as the distalising tibial tubercle osteotomy procedure group, are eligible for inclusion in the study. Patients will be randomised to either the fast rehabilitation group or the traditional rehabilitation group. Patients with patellar instability will be additionally treated with medial patellofemoral ligament reconstruction. The hypothesis of the trial is that the novel accelerated rehabilitation protocol will lead to faster recovery and improved functional outcome at 6, 12 and 24 weeks compared with the conservative rehabilitation protocol. A secondary hypothesis is that the complication rate will be similar in both groups. The study will document short-term recovery and the planned follow-up will be 3 years. After the 1-year follow-up, the trial results will be disseminated in a major peer-reviewed orthopaedic publication. Protocol version 3.6, date 28/11/2023.

A Randomized Controlled Trial Comparing a Patella-Stabilizing, Motion-Restricting Knee Brace Versus a Neoprene Nonhinged Knee Brace After a First-Time Traumatic Patellar Dislocation.

BACKGROUND: A traumatic lateral patellar dislocation is a common injury in adolescents and young adults. The majority of first-time dislocations can be treated nonoperatively. Various types of knee braces are used for nonoperative treatment, but evidence on the most preferable bracing method is lacking. PURPOSE: To evaluate the efficacy of a patella-stabilizing, motion-restricting knee brace versus a neoprene nonhinged knee brace for the treatment of a first-time traumatic patellar dislocation at 3 years of follow-up. STUDY DESIGN: Randomized controlled trial; Level of evidence, 1. METHODS: A total of 101 skeletally mature patients with a first-time traumatic patellar dislocation were enrolled in the study. After exclusion criteria were applied, 79 patients with a first-time traumatic patellar dislocation were randomized and allocated into 2 study groups: group A, with a patella-stabilizing, motion-restricting knee brace (hinged to allow knee range of motion [ROM] of 0°-30°) and group B, with a neoprene nonhinged knee brace (not restricting any knee motion). Both groups received similar physical therapy instructions and were advised to use the brace continuously for 4 weeks. Overall, 64 patients completed the trial. RESULTS: The redislocation rate in group A was 34.4% (11/32) and in group B it was 37.5% (12/32) (risk difference, -3.1% [95% CI, -26.6% to 20.3%]; P = .794). Patients in group A had less knee ROM than those in group B at 4 weeks (90° vs 115°, respectively; P < .001) and 3 months (125° vs 133°, respectively; P = .028). Patients in group A had more quadriceps muscle atrophy than patients in group B at 4 weeks (24/32 vs 16/32, respectively; P = .048) and 3 months. At 6 months, patients in group B reported better functional outcomes than patients in group A (Kujala score mean difference, 4.6; P = .012), although no clinically relevant difference was found at 3 years. CONCLUSION: The use of a patella-stabilizing, motion-restricting knee brace for 4 weeks after a first-time traumatic patellar dislocation did not result in a statistically significant reduction in redislocations versus a neoprene nonhinged knee brace, although this trial was underpowered to detect more modest differences. Knee immobilization was associated with quadriceps muscle atrophy, less knee ROM, and worse functional outcomes in the first 6 months after the injury. REGISTRATION: NCT01344915 (ClinicalTrials.gov identifier).

Anatomic and Biomechanical Properties of Flat Medial Patellofemoral Ligament Reconstruction Using an Adductor Magnus Tendon Graft: A Human Cadaveric Study.

BACKGROUND: In contrast to the majority of existing techniques for reconstruction of the medial patellofemoral ligament (MPFL), the technique described in this article uses the adductor magnus muscle tendon to gain a flat, broad graft, leaving its distal femoral insertion intact, and does not require drilling within or near the femoral physis. It also allows for soft tissue patellar fixation and could facilitate anatomic MPFL reconstruction in skeletally immature patients. PURPOSE: To evaluate the anatomic and structural properties of the native MPFL and the adductor tendon (AT), followed by biomechanical evaluation of the proposed reconstruction. STUDY DESIGN: Descriptive laboratory study. METHODS: The morphological and topographical features of the AT and MPFL were evaluated in 12 fresh-frozen cadaveric knees. The distance between the distal insertion of the AT on the adductor tubercle and the adductor hiatus, as well as the desired length of the graft, was measured to evaluate this graft's application potential. Load-to-failure tests were performed to determine the biomechanical properties of the proposed reconstruction construct. The construct was placed in a uniaxial testing machine and cyclically loaded 500 times between 5 and 50 N, followed by load to failure, to measure the maximum elongation, stiffness, and maximum load. RESULTS: The mean ± SD length of the AT was 12.6 ± 1.5 cm, and the mean distance between the insertion on the adductor tubercle and adductor hiatus was 10.8 ± 1.3 cm, exceeding the mean desired length of the graft (7.5 ± 0.5 cm) by 3.3 ± 0.7 cm. The distal insertion of the AT was slightly proximal and posterior to the insertion of the MPFL. The maximum elongation after cyclical loading was 1.9 ± 0.4 mm. Ultimately, the mean stiffness and load to failure were 26.2 ± 7.6 N/mm and 169.7 ± 19.2 N, respectively. The AT graft failed at patellar fixation in 2 of the initially tested specimens and at the femoral insertion in the remaining 10. CONCLUSION: The described reconstruction using the AT has potential for MPFL reconstruction. The AT graft presents a graft of significant volume, beneficial anatomic topography, and adequate tensile properties in comparison with the native MPFL following the data from previously published studies. CLINICAL RELEVANCE: Given its advantageous anatomic relationship as an application that avoids femoral drilling and osseous patellar fixation, the AT may be considered a graft for MPFL reconstruction in skeletally immature patients.

The incidence of paediatric ACL injury is increasing in Finland.

PURPOSE: Anterior cruciate ligament (ACL) injury is a common knee injury in paediatric and adolescent patients. The population-based incidence of paediatric ACL injury is, however, unknown. Recent studies suggest increased ACL injury rates among adolescents, especially in active, sports-participating population. The purpose of this study was to investigate the population-based incidence rates of ACL injuries and trends in paediatric ACL reconstruction surgery. METHOD: All ACL injuries were identified (ICD-10 diagnosis code S83.5) leading to hospitalisation or surgery using validated Finnish National Hospital Discharge Register (NHDR) data from 1997 to 2014. The sample comprised 19,961,205 Finnish residents aged less than 18 years at the time of injury. Hospital admissions with the diagnosis code S83.5 were analysed more thoroughly including, sex, age and the need for surgical interventions. RESULTS: During the 18-year study period, 4725 subjects of the study population had sustained an ACL injury. The total ACL injury incidence in study population was 23.3 per 100,000 person-years. The median age of the patients at the time of injury was 16 years (range 4-17). The incidence of ACL injury increased with age, and the highest incidence was observed among 17-year old (113.5 per 100,000 person-years). Incidence rate did not differ between genders. From the total ACL injury population of 4725 hospitalisations, 3168 (67.0%) underwent ACL reconstruction, of which 2988 (94.3%) were treated with arthroscopic reconstruction and 180 (5.6%) with open surgery. In addition, 1557 (33.0%) were treated non-operatively without ACL reconstruction. The annual incidence of ACL injuries in the Finnish paediatric population has increased during the past 15 years. The lowest incidence rate was seen in 1999 (incidence of 17.7 per 100,000 person-years, 195 ACL injuries) and the highest in 2011 (incidence of 31.5 per 100,000 person-years, 346 ACL injuries). The highest increase in ACL injuries was seen in girls aged 13-15 years, with an increase of 143%. CONCLUSION: ACL injury is not a negligible knee injury in the paediatric population. The incidence of paediatric ACL injury has increased during the past 15 years. Moreover, a twofold increase in incidence of paediatric ACL injury was noted during the last 10 years of the study period. Incidence rates among male and female paediatric patients were comparable. LEVEL OF EVIDENCE: III.

Bioabsorbable Versus Metal Screw in the Fixation of Tibial Tubercle Transfer: A Cadaveric Biomechanical Study.

BACKGROUND: In tibial tubercle transfer (TTT) procedures, the osteotomized and transferred tibial tubercle is usually fixed into the host bone using metal screws. PURPOSE: To compare the strength of fixation provided by a single bioabsorbable screw versus a metal screw for TTT. STUDY DESIGN: Controlled laboratory study. METHODS: Twenty-two pairs of human cadaveric tibiae were used to compare the fixation strength of a single 4.5-mm bicortical bioabsorbable or metal screw for TTT. In our 2-phase biomechanical testing protocol, the specimens were first subjected to a cyclic-loading test (1500 loading cycles between 50 and 300 N at 0.5 Hz frequency), after which they were loaded to failure (single-cycle load-to-failure test). To control for possible differences in bone quality, volumetric bone mineral density was determined using peripheral quantitative computed tomography. RESULTS: No significant displacement differences were observed between the 2 groups for the cyclic-loading test. In the subsequent single-cycle load-to-failure test, the mean yield load was 566 ± 234 N in the bioabsorbable screw group and 984 ± 630 N in the metal screw group (P = .002). The failure mode of bioabsorbable screws was breakage and/or bending, and that of metal screws was bending and/or pull-out. Bone density was similar in the 2 groups. CONCLUSION: A metal screw seems to provide greater fixation strength than a biodegradable screw in the TTT of a human cadaveric knee. However, considering the maximum quadriceps pull in vivo, the strength of fixation provided by a biodegradable screw seems clinically sufficient. CLINICAL RELEVANCE: Bioabsorbable screws, particularly if used in duplicate, could provide a viable option for metal screws in TTT fixation.

Traumatic Patellar Dislocation and Cartilage Injury: A Follow-up Study of Long-Term Cartilage Deterioration.

BACKGROUND: Patellofemoral cartilage deterioration and osteoarthritis are reported to be associated with recurrent patellar dislocation. However, the association between first-time traumatic patellar dislocation and cartilage deterioration is unknown. PURPOSE: The aim of this study was to assess long-term cartilage deterioration in the patellofemoral and tibiofemoral joint after conservatively treated traumatic lateral patellar dislocation. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Twenty patients (mean age, 25 years) who sustained first-time traumatic lateral patellar dislocation with no previous patellofemoral instability symptoms were initially scanned with 1.5-T magnetic resonance imaging (MRI). A follow-up 3-T MRI was conducted, on average, 8 years after first-time lateral patellar dislocation. Subjective instability symptoms and Knee injury and Osteoarthritis Outcome Score were also assessed. RESULTS: In the primary MRI, patellofemoral cartilage injury was seen in 14 of 20 patients (70%). Most (14/15) of the injuries were seen in the patellar cartilage, especially at the medial facet. On the follow-up MRI, patellofemoral cartilage deterioration was visible for all patients. The central patella ( P = .005) seemed especially prone to cartilage deterioration during the follow-up. Half of the patients (10/20) had grade 3-4 cartilage lesions in the patellofemoral joint in the follow-up MRI. In the primary MRI, only 1 patient exhibited tibiofemoral joint cartilage lesions, whereas at the time of follow-up, 10 of 20 patients exhibited tibiofemoral cartilage lesions. The majority of these lesions were considered clinically nonsignificant (International Cartilage Repair Society = 1) and were seen in the lateral compartment (6/10, 60%). Of the 14 patients (36%) with injury to the patellar cartilage, 5 reported subsequent instability of the patellofemoral joint, but this was not associated with more significant cartilage deterioration in the follow-up MRI compared with patients without redislocation. CONCLUSION: While recurrent lateral patellar dislocation is known to lead to degenerative process, a single first-time or infrequently recurring traumatic lateral patellar dislocation also seems to be associated with gradual cartilage deterioration. Traumatic lateral patellar dislocation might initiate gradual degeneration of the cartilage in the patellofemoral joint and can lead to the development of generalized knee osteoarthritis. Instability symptoms of the patellofemoral joint, however, were not related to the severity of the deterioration.

Declining incidence of surgery for Achilles tendon rupture follows publication of major RCTs: evidence-influenced change evident using the Finnish registry study.

OBJECTIVES: Acute Achilles tendon ruptures are common among highly active people. Recently published studies have provided increasing evidence to support non-surgical treatment. This study aimed to assess the incidence trends of surgically treated, acute Achilles tendon ruptures. Our hypothesis, based on the recent literature showing no difference in functional results between surgical and non-surgical treatment, was that the incidence of surgery would be declining. METHODS: We conducted a nationwide hospital register-based study. All patients 18 years of age or older with a diagnosis of acute Achilles tendon injury, and treated with Achilles tendon repair from 1987 to 2011 in Finland were included in the study. RESULTS: During the 25-year study period in Finland, a total of 15,252 patients received surgical treatment for an acute Achilles tendon rupture. The incidence of surgical treatment of acute Achilles tendon rupture in men was 11.1/100,000 person-years in 1987 and 20.5/100,000 person-years in 2011. The corresponding figures in women were 2.5/100,000 person-years in 1987 and 4.2/100,000 person-years in 2011. The highest rates occurred in 2008 in men and 2007 in women, and since then the decrease has been 42% in men and 55% in women. CONCLUSIONS: During the past few years, the rate of surgically treated acute Achilles tendon ruptures has declined remarkably. The findings of the present study indicate that orthopaedic surgeons have chosen more often non-surgical treatment option for acute Achilles ruptures. This can be considered as an example, how high-quality scientific evidence can lead to a rapid change in clinical practice.

Medial patellofemoral ligament avulsion injury at the patella: classification and clinical outcome.

PURPOSE: To define medial patellofemoral ligament (MPFL) injury characteristics at the patellar attachment and clinical outcome in patients with primary traumatic patellar dislocation and MPFL avulsion injury at the patella. METHODS: Magnetic resonance imaging (MRI) was used to assess patients with primary (first-time) patellar dislocation and MPFL injury at the medial margin of the patella. Fifty-six patients with patellar attachment MPFL injury were enrolled in the study. Thirteen patients underwent surgical fixation of the avulsed MPFL and patellar medial margin osteochondral fracture, and the remaining patellar MPFL injures were treated nonoperatively. Forty-four patients were evaluated clinically at median four (range 1-10) years after patellar dislocation. The follow-up included evaluation of recurrent patellar instability, subjective symptoms, and functional limitations. RESULTS: Three types of patellar MPFL injuries were found; type P0 with ligamentous disruption at the patellar attachment, type P1 with bony avulsion fracture from the medial margin of the patella, and type P2 with bony avulsion involving articular cartilage from the medial facet of the patella. Of the patellar MPFL avulsion injuries that underwent initial surgical fixation, two patients (2/13) reported an unstable patella at follow-up. Fifty-five per cent (17/31) of patellar MPFL avulsion injuries that were treated nonoperatively had recurrent patellar instability (n.s.). The median Kujala score was 90 for patellar avulsion with surgical fixation and 86 for patellar avulsion without surgical fixation (n.s.). CONCLUSION: Patellar attachment MPFL injury showed three different patterns, classified as types P0, P1, and P2. MRI can be used to assess the injury pattern. Patellar MPFL avulsion injuries do not benefit from acute surgical repair compared with nonsurgical treatment. Type P2 patellar MPFL avulsion includes an osteochondral fracture that may require surgical fixation. LEVEL OF EVIDENCE: Prognostic study, Level III.

[Treatment of anterior cruciate ligament rupture]. / Eturistisiderepeämän hoito.

Anterior cruciate ligament rupture of the knee is a common knee injury associated with sports and exercise. The injury typically arises when the foot is tightly locked against the floor or ground, whereby a sudden change of direction combined with the slowed motion causes a rotary motion of the upper part of the tibia and a force rupturing the cruciate ligament. Approximately 30% of the injuries take place during a situation of direct contact. The instability of the knee due to the rupture may be strongly invalidizing. In such case surgical therapy is required, if appropriate conservative treatment does not lead to a good result.

Incidence of knee dislocation and concomitant vascular injury requiring surgery: a nationwide study.

BACKGROUND: Acute knee (tibiofemoral joint) dislocation is a serious knee injury, although population-based numbers and incidence rates of knee dislocation with or without concomitant vascular injury are unknown. METHODS: The study covered the whole adult population of 4 million persons (aged ≥ 18 years) in Finland during the 11-year period from January 1, 1998, to December 31, 2011. Data on hospitalization caused by acute knee dislocations and concomitant vascular injuries requiring operative treatment were obtained from the nationwide National Hospital Discharge Registry. RESULTS: During the 14-year study period, a total of 837 patients with knee dislocation diagnosis were hospitalized in Finland. The highest incidence rates in men were in persons aged 18 years to 29 years (incidence, 29 per 1 million person-years in 2011), and the incidence decreased by age, while in women, this incidence was rather similar in all age groups. The most common injury mechanism of knee dislocation was low-energy fall at the same level (46%). The median length of hospital stay was 2 days (range, 1-109 days). In 107 cases (13%), knee dislocation required immediate open (69 cases) or closed (38 cases) reduction in the operating room. Popliteal artery injury requiring acute surgical intervention was found in 13 patients (1.6%), and amputation at the level above the tibiofemoral joint was performed for one patient (0.1%). CONCLUSION: This is the first study describing the population-based incidence of acute knee dislocation. Men aged 18 years to 29 years had the highest incidence rates. Half of the injuries were low-energy trauma. Popliteal artery injury requiring surgical intervention was a rare concomitant injury, but when present, the injury required immediate surgical repair to avoid dramatic consequences. LEVEL OF EVIDENCE: Nationwide epidemiologic study, level I.

Medial patellofemoral ligament: anatomy, injury and treatment in the adolescent knee.

PURPOSE OF REVIEW: Traumatic and nontraumatic patellofemoral instability (PFI) in children and adolescents is a complex problem. It is determined by a large number of mechanical and pathomorphologic conditions, mainly seen in nontraumatic dislocations. RECENT FINDINGS: Although conservative treatment with a short immobilization, followed by early passive motion and isometric quadriceps strengthening, can be considered in real traumatic dislocations without any cartilaginous injury, a surgical intervention should be considered in atraumatic cases. As 90% of PFI are nontraumatic and correlated with skeletal deformities, the redislocation rate is reported to be up to 80% after initial conservative treatment. To optimize the results, the causing disorder for PFI has to be considered imperatively. In addition to bony disorder, further risk factors have to be taken into consideration for determining the optimal time for surgery. As biomechanical and clinical studies have shown the importance of the medial patellofemoral complex, especially the medial patellofemoral ligament (MPFL), against patellar lateralization, the reconstruction or minimally invasive double-bundle reconstruction of the MPFL is the main surgical technique to treat PFI in children, as it can be used even in open epiphysial cartilage. Further surgical interventions correcting bone deformities, such as trochleoplasty or tibial tubercle osteotomies addressing lower limb deformities, should be performed after closure of the epiphysial cartilage. SUMMARY: It is the goal of this overview to explain the pathoanatomy of PFI, the demanding clinical and radiological examinations and treatment options.

First-time patellar dislocation: surgery or conservative treatment?

Primary patellar dislocation injures the medial patellofemoral ligament (MPFL), the major soft-tissue stabilizer of the patella, which may lead to recurrent patellar instability. Recurrent patellar dislocation are common and may require surgical intervention. The variation in location of injury of the MPFL and the presence of an osteochondral fracture produces challenges in clinical decision making between nonoperative and operative treatment, including the surgical modality, to repair or reconstruct the MPFL. Current evidence suggests that not all primary dislocations should undergo the same treatment. MPFL reconstruction may theoretically be more reliable than repair, but the optimal time to perform additional bony corrections is not known. A normal or minor dysplastic patellofemoral joint may be suitable for nonoperative treatment, whereas a higher grade of trochlear dysplasia or other significant abnormalities may benefit from surgical treatment. In this paper, we present a treatment algorithm for primary patellar dislocation.

[Patellar luxation in a young adult]. / Nuoren aikuisen polvilumpion sijoiltaanmeno.

Damage of the medial patellofemoral ligament in connection with traumatic patellar luxation is important to recognize. Repair or reconstruction of this structure prevents the recurrence of patellar luxation. Anatomy of the patellofemoral joint, on the other hand, has significant effect on patellar stability, whereby the same procedure is not appropriate for everybody. Some patients with traumatic patellar luxation will benefit from early-stage surgical treatment, some heal equally well by conservative treatment. Previous problems of the treatment of patellar luxation, i.e. poorly predictable recovery and relatively poor results of the surgery, have turned into challenges in the selection of individual therapy and timing of surgery.

Significant change in the surgical treatment of distal radius fractures: a nationwide study between 1998 and 2008 in Finland.

BACKGROUND: Studies from the United States report a large increase in the surgical treatment of distal radius fractures with open reduction and internal fixation using locked plates. The aim of the present study was to determine whether the same trend has occurred in a Scandinavian country by assessing the number, incidence, and surgical methods of all surgically treated distal radius fractures in Finland over a recent 11-year period. METHODS: The study covered the whole adult population (aged >19 years) in Finland during the 11-year period from January 1, 1998, to December 31, 2008. Data on surgically treated distal radius fractures were obtained from the nationwide National Hospital Discharge Registry. RESULTS: During the 11-year study period, a total of 14,514 surgical operations (external fixation, percutaneous pinning, or plating) for adult distal radius fractures were performed in Finland. There was a dramatic shift toward internal fixation with plating; the incidence and number of platings more than doubled between 2006 and 2008. The incidence and number of external fixations decreased correspondingly. Percutaneous pinning was used in 13% of the surgical procedures during the study period. CONCLUSIONS: A striking shift from external fixation to plating in the treatment of distal radius fractures has occurred in Finland over the past few years, despite the fact that the scientific literature does not support plating over external fixation. In addition, the incidence and number of surgeries for distal radius fractures doubled between 1998 and 2008. The reasons for these changes are not known.

Patellofemoral osteoarthritis in patients with operative treatment for patellar dislocation: a magnetic resonance-based analysis.

PURPOSE: the clinical role of patellofemoral (PF) osteoarthrosis (OA) in the outcome after PF stabilizing surgery is poorly understood. The study hypothesis was that PF cartilage lesions and OA are associated with a poor long-term outcome after PF stabilizing surgery. METHODS: the study cohort included thirty-seven patients who underwent PF stabilizing surgery by traditional nonanatomic procedures and were evaluated a minimum of 10 years (range 10-21) after surgery. PF OA was assessed by magnetic resonance (MR) images and plain radiographs obtained at follow-up. Median patient age at follow-up was 33 years (29-43). RESULTS: at the final follow-up, PF full-thickness cartilage lesions were observed on MR images in 29 (78%) patients. Only 46% of the patients reported satisfaction at follow-up, and dissatisfaction was associated with PF OA (full-thickness articular cartilage loss on MR images; P = 0.022). Especially high incidence, 89%, of medial patellar facet cartilage lesions were found among the patients dissatisfied with the result (16/18 patients) (n.s.). Eight (22%) of the 37 patients reported recurrent patellar instability episodes at follow-up. Median Kujala score was 83 points (range 55-98). CONCLUSION: patellofemoral OA is a significant long-term risk of nonanatomic surgery for patellar instability and has a greater impact on subjective outcome than residual instability more than 10 years after surgery.

Orthotic insoles do not prevent physical stress-induced low back pain.

Orthotic insoles are suggested to prevent low back pain. This randomized controlled study assessed if customised orthotic insoles prevent low back pain. Healthy military conscripts (n = 228; mean age 19 years, range 18-29) were randomly assigned to use either customised orthotic insoles (treatment group, n = 73) or nothing (control group, n = 147). The main outcome measure was low back pain requiring a physician visit and resulting in minimum 1 day suspension from military duty. Twenty-four (33%) treated subjects and 42 (27%) control subjects were suspended from duty due to low back pain (p = 0.37; risk difference 4.3%; 95% CI: -8.7 to 17.3%). Mean suspension duration was 2 days (range 1-7) in both groups. Four (5%) treated subjects and eight (5%) control subjects were released from duty due to persistent low back pain (p = 0.92; risk difference 0%; 95% CI: -6 to 6%). Use of orthotic insoles is therefore not recommended to prevent physical stress-related low back pain.

Bone bruise in acute traumatic patellar dislocation: volumetric magnetic resonance imaging analysis with follow-up mean of 12 months.

OBJECTIVE: The aim of the study was to assess volumetric analysis of bone bruises in acute primary traumatic patellar dislocation by magnetic resonance imaging (MRI) and resolving resolution of bruises in follow-up MRI. MATERIALS AND METHODS: MRI was performed in 23 cases. A follow-up examination was done at a mean of 12 months after dislocation. Volumes of patellar and femur bruises for every patient were evaluated separately by two musculoskeletal radiologists, and mean values of the bruises were assessed. Other MRI findings were evaluated, together with agreement by consensus. Bone bruise volumes were compared with other MR findings. RESULTS: In the acute study 100% of patients showed bruising of the lateral femoral condyle and 96% bruising of the patella. The bruise was located at the medial femoral condyle in 30% and at the patellar median ridge in 74% of patients. The median volume of the femoral bruise was 25,831 mm(3) and of the patellar bruise 2,832 mm(3). At the follow-up study 22% of patients showed bruising of the lateral femoral condyle and 39% bruising of the patella, the median volumes of the bruises being 5,062 mm(3) and 1,380 mm(3), respectively. Larger patellar bruise volume correlated with larger femur bruise volume in the acute (r = 0.389, P = 0.074) and the follow-up (r = 1.000, P < 0.01) studies. Other MRI findings did not correlate significantly with bone bruise volumes. CONCLUSION: Bone bruising is the commonest finding in cases of acute patellar dislocation, being seen even 1 year after trauma and indicating significant bone trabecular injury in the patellofemoral joint. A large bruise volume may be associated with subsequent chondral lesion progression at the patella. We concluded that the measurement of bone bruise volume in patients with acute patellar dislocation is a reproducible method but requires further studies to evaluate its clinical use.