Femoral Lengthening Might Impair Physical Function and Lead to Structural Changes in Adjacent Joints; 10 Patients With 27 to 34 Years Follow-up.
Phase: NA
Conditions: Leg Length Inequality, Leg; Lengthening, Osteoarthritis, Knee, Osteoarthritis of Hip, Quality of Life
Sponsor: Oslo University Hospital

NCT03966573 
 
 
 
 
Title: «Evaluation of physical function, Quality of Life and Hip- and Knee 
Osteoarthritis Minimum 15 years After femoral Lengthening». 
 
 
 
 
 
 
 
Date: 01.06.2018 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

Introduction  
 
Limb lengthening is an established method for treatment of leg length discrepancy 
(anisomelia) or short stature (Castelein & Docquier, 2016; Steen, Terjesen, & Bjerkreim, 
1997). The most common cause of limb lengthening is anisomelia (Castelein & Docquier, 
2016). Anisomelia can either be innate or acquired, for instance after an injury (Castelein & 
Docquier, 2016). At Oslo University Hospital, it is performed 15-20 lower extremity 
lengthening procedures yearly including tibial and femoral lengthening. The vast majority of 
these are performed on patients with congenital deformities or other skeletal pathologies, and 
only a few are without a clear diagnosis or with acquired leg length discrepancy. Leg length 
discrepancy can be problematic as it often causes pelvic tilt towards the short side (Steen et 
al., 1997). This again, can cause functional scoliosis, largely affecting the gait (Steen et al., 
1997). It is documented that anisomelia of more than two cm should be treated (Steen et al., 
1997). Treatment could be either conservative by using shoe lift or surgical, where the long 
leg could be shortened or the short leg lengthened (Steen et al., 1997). In growing children 
there´s also the possibility to stop growth in the long leg at a certain time to achieve leg length 
equality (isomelia) (Steen et al., 1997). In many patients, limb lengthening will of various 
reasons be preferred, if the discrepancy is over three cm (Steen et al., 1997).  
 
There are described several limb lengthening methods, for instance the Wagner method and 
the Ilizarov technique (Ilizarov, 1988; Wagner, 1971). The callotasis principle (distraction 
osteogenesis or callus distraction) described by Gavril A. Ilizarov is the most trusted and 
accepted method (Castelein & Docquier, 2016; Paley, 1990), and all patients invited to 
participate in this project are lengthened with callotasis. With the callotasis method the bone 
is stabilized at least two places with a fixator before the surgeon makes a corticotomy 
between the fixations (Ilizarov, 1988). Bone and soft tissue are lengthened by regeneration 
under conditions of tension stress when the bone fragments on each side of the corticotomy is 
pulled apart, usually 0.75 - 1 mm a day distributed over three to four sequences until goal of 
lengthening is achieved (Ilizarov, 1988; Maffulli, Pattinson, & Fixsen, 1993; Paley, 1990). 
 
In our study we will concentrate on femoral lengthening as it appear more homogenous than 
tibial regarding healing and complications (Maffulli et al., 1993). In addition, unlike tibia, 
femur has large two-joint muscle groups surrounding it (Maffulli et al., 1993), making it more 
relevant for us investigating adjacent joint function than with tibial lengthening. Most patients 

regain full range of motion in their hip and knee after femoral lengthening with callotasis 
(Barker, Simpson, & Lamb, 2001; Bhave et al., 2017; Herzenberg, Scheufele, Paley, Bechtel, 
& Tepper, 1994; Holm, Steen, Ludvigsen, & Bjerkreim, 1995; Horn, Grimsrud, Dagsgard, 
Huhnstock, & Steen, 2015; Kawoosa, Majid, Halwai, Mir, & Mir, 2004; Maffulli, Nele, & 
Matarazzo, 2001; Motmans & Lammens, 2008; Zambito & Aldegheri, 1997). However, limb 
lengthening is associated with high risk of complications, where loss of knee extension is 
most commonly reported (Fitch, Thompson, Rizk, Seaber, & Garrett Jr, 1996; Paley, 1990). 
Infections, subluxation of the hip- or knee joint, premature healing, lack of healing, 
development of deformities after fixator removal, fractures after conclusion of lengthening, 
reduced gross motor skills and more pain than healthy controls are other known complications 
associated with limb lengthening (Castelein & Docquier, 2016). We have found studies both 
indicating muscle weakness, and unchanged muscle strength after femoral lengthening with 
callotasis (Bhave et al., 2017; Holm et al., 1995; Krieg, Gehmert, Neeser, Kaelin, & Speth, 
2018; Oey, Engelbert, & Wieneke, 1999). These are all small studies with different design 
and patient basis, making them hard to compare. Some studies report good functional 
outcome after femoral lengthening, but the measurement of function is poorly defined and 
described in these studies (Eralp, Bilen, Dikmen, & Eren, 2012; Zambito & Aldegheri, 1997). 
We have only found two studies describing health status and quality of life after femoral 
lengthening with callotasis. Shahcheraghi et al. (2015) found no deterioration regarding 
function, quality of life and health status comparing pre- and postoperative status, while 
Moraal et al. (2009) found that patients had physical limitations, but normal psychosocial 
function and self-esteem compared to healthy normal population. Quality of life were 
comparable to healthy normal population, except from significantly lower gross motor 
function, vitality, and more pain. There is lack of research on physical function, quality of 
life, health status and activity level after femoral lengthening with an obvious need for further 
research with good statement of both patient group and method. 
 
Textbooks describing limb lengthening claims that it increases the risk of osteoarthritis 
(Sneppen, Bünger, Hvid, & Søballe, 2014), but to our knowledge this statement lacks research 
evidence and appears more like an assumption. Animal research have shown tendencies of 
knee osteoarthritis after femoral lengthening (Stanitski, 1994), but we have only succeeded in 
finding one article that describes osteoarthritis development after femoral lengthening on 
humans, where 18 out of 23 patients showed knee osteoarthritis with a mean follow-up of 6 
years after femoral and / or tibial lengthening (Jeong, Inan, Riddle, Gabos, & Bowen, 2006). 

It is an interesting finding, but this study used another lengthening method than today’s gold 
standard of callotasis and were performed on patients with congenital femoral deficiency. It is 
hard to say if the osteoarthritis seen in these patients is in context with the lengthening 
procedure with their method of choice or the patient’s pathology. It is important to know if 
the procedure itself increases the risk of developing osteoarthritis. In our study we will 
therefore only include patients with idiopathic or acquired leg length discrepancy, minimizing 
as far as we can the risk of the patient´s pathology being the explanatory factor for eventual 
findings. Socioeconomically it´s relevant to know whether limb lengthening increases the risk 
of osteoarthritis, as the condition leads to pain and reduced function, and can cause 
considerable costs regarding sick leaves, medications, physiotherapy and possibly prosthetic 
operations (Bitton, 2009; Grotle, Hagen, Natvig, Dahl, & Kvien, 2008). It can take time from 
an initial factor until osteoarthritis can be confirmed by conventional radiology, and all the 
research we have been able to find describing consequences of limb lengthening, all have 
relatively short follow-up, mostly far below ten years. With the lack of research available in 
the question of context between limb lengthening and risk of osteoarthritis, there is an 
obvious need for more research to investigate this with long enough follow-up to be able to 
identify osteoarthritis within the patient group. 
 
There is of considerable value to both patients and treating health professionals to be aware of 
what long term consequences to expect after limb lengthening when operative or conservative 
strategy of treatment is to be decided. Based on this, we want to evaluate physical function, 
quality of life and development of hip- and knee osteoarthritis minimum 15 years after 
femoral lengthening due to idiopathic or acquired leg length discrepancy. 
 
Responsibility and sponsorship 
 
Oslo University Hospital is responsible for the study, and Sophies Minde AS has sponsored 
the project by granting a research scholarship paying the salary for the researcher to be able to 
implement this study. All data will be collected at Oslo University Hospital. Radiologic 
examinations will be performed by radiographic section at Oslo University Hospital, while all 
other data will be collected by the researcher. 
 
Purpose of the study and research questions 
 

The purpose of this study is to evaluate physical function (range of motion, 30 seconds sit to 
stand test, stair test and hop tests), quality of life, health status, activity level and development 
of osteoarthritis in the hip- and knee joint minimum 15 years after femoral lengthening due to 
idiopathic or acquired leg length discrepancy. 
 
Research questions: 
1. Are there differences in physical function in the lower extremities in patients who 
have undergone femoral lengthening compared to reference values? 
2. Do patients who have undergone femoral lengthening achieve recommendations for 
physical activity? 
3. Are there differences in quality of life in patients who have undergone femoral 
lengthening compared to reference values? 
4. Are there differences in health status in patients who have undergone femoral 
lengthening compared to reference values? 
5. Are there differences in development of osteoarthritis in lengthened and unlengthened 
hip- and knee joint in patients who have undergone femoral lengthening? 
 
Design, material and method 
 
This study is a quantitative cross-sectional study.  
 
Patients 
 
Includable patients for this study will be identified from protocols from the surgical 
department.  
 
Inclusion criteria: Patients with idiopathic (unknown cause) or post traumatic leg length 
discrepancy, that has been operated with femoral lengthening with callotasis minimum 15 
years ago. 
 
Exclusion criteria: Innate skeletal pathology leading to shortening of the lower extremity, 
malangulation and less developed musculature, such as congenital femoral deficiency (CFD) 
or fibular hemimelia (Jeong et al., 2006). Patients with acquired leg length discrepancy after 

infection in hip- or knee joint, and patients that have inserted hip- or knee prosthesis will also 
be excluded. 
 
Data collection 
 
All examinations will be completed at the same day at Oslo University Hospital. 
 
Outcome measures 
 
Physical function 
Active range of motion (AROM) of the hip- and knee joint will be measured in degrees with 
an analog goniometer. Even though goniometric measures have uncertainties, acceptable 
intra-tester reliability is shown in hip and knee measurements with analog goniometer (Holm 
et al., 2000; Watkins, Riddle, Lamb, & Personius, 1991).  
 
30 seconds sit to stand test (30sSTS) measures lower extremity strength (Bennell, Dobson, & 
Hinman, 2011; Csuka & McCarty, 1985). Chair with height of 44-45 cm will be used. The 
participant is told to sit and stand as many times as possible within 30 seconds, and the total 
number is registered (Tveter, Dagfinrud, Moseng, & Holm, 2014).  
 
Stair test measures submaximal cardiopulmonary endurance (Cataneo & Cataneo, 2007). The 
participant is asked to move as fast as possible 18 stairs (17±1 cm) up and down three 
consecutive times. Total time in seconds is registered. The participant is allowed to run and 
use the banister if needed. The participant has to step on every stair. Pulse is measured, and 
Borg scale 6-20 registered immediately after the test (Tveter et al., 2014).  
 
Hop tests will be used to compare function in the lengthened and unlengthened limb. The tests 
are developed for patients with ACL ruptures, but the high specificity and low false positive 
rates found is an argument for us to use it to separate the limbs from each other and confirm if 
there is impaired lower limb function (Noyes, Barber, & Mangine, 1991). Single hop for 
distance, triple hop for distance, timed hop (seconds used to hop 6 m) and cross-over hop for 
distance (triple cross-over hop over 15 cm wide tape) will be performed on both legs.  
 
Questionnaires 

Knee Osteoarthritis Outcome Score (KOOS) is a self-administered questionnaire. It has 
shown validity and reliability measuring function and pain in patients with knee injuries and 
osteoarthritis (Roos & Lohmander, 2003; Roos, Roos, Lohmander, Ekdahl, & Beynnon, 
1998). The participant answer questions regarding pain, function, stiffness and quality of life 
regarding knee pain.  
 
EQ-5D-5L has shown validity and reliability measuring health related quality of life in 
patients with hip- and knee pain (Fransen & Edmonds, 1999). It is a self-administered 
questionnaire where the participants report the extent of problems they have in the five 
dimensions mobility, self-care, usual activities, pain/discomfort and anxiety/depression. The 
questionnaire also contains a vertical analogue scale with the labelled endpoints 0-100 giving 
a valuation of the participants own health state that can be used as a quantitative measure of 
health outcome based on the patients’ own judgement. The use of this questionnaire is 
approved by EuroQol.  
 
International Physical Activity Questionnaire (IPAQ) short version has shown validity and 
reliability, and is a self-administered questionnaire used to obtain estimates of  physical 
activity level (Cerin et al., 2016). Participants answer the amount of time being in vigorous 
activity, moderate activity, walking and sitting during the last 7 days. This will be transitioned 
into MET-score.  
 
Radiology 
Osteoarthritis in hip- and knee joints will be evaluated by measuring joint space width (JSW) 
and Kellgren & Lawrence classification (KL) (Terjesen & Gunderson, 2012). Leg length 
equality will be evaluated with standing axis measurements. All radiologic measurements are 
done by an experienced radiologist at Oslo University Hospital. Lengthened side will be 
compared to unlengthened side.  
 
Analyzes 
 
AROM in the hip and knee joint: The lengthened and unlengthened side will be compared 
using to-sample t-test.  
 

30Ssts: We will analyze if there is a difference between patients that have undergone femoral 
lengthening and reference values with Wilcoxon signed ranks test (Tveter et al., 2014). 
 
Stair test: We will analyze if there is a difference between patients that have undergone 
femoral lengthening and reference values with Wilcoxon signed ranks test. 
 
Hop tests: The results will be analyzed comparing lengthened and unlengthened side using 
Wilcoxon signed ranks test. 
 
KOOS: To analyze if there is a difference between patients that have undergone femoral 
lengthening and reference values, one-sample t-test will be used. 
 
EQ-5D-5L: We will analyze if there is a difference between patients that have undergone 
femoral lengthening and reference values with one-sample t-test 
 
IPAQ: To analyze if the patients meet recommendations for physical activity of 600 MET, 
one-sample t-test will be used (ASCM, 2013). 
 
JSW and KL: Evaluation of osteoarthritis development in the lengthened and unlengthened 
side will be presented by descriptive statistics. 
 
Research ethics assessment 
 
Possible negative consequences of this project are that the participants will have to use their 
time without being economically compensated, and they will be exposed to x-rays that are not 
medically induced. On the other hand, the participants are offered a thorough examination of 
their hips and knees, both clinically and radiological, in addition to participate in research that 
may be beneficial for other patients going through the same procedure. 
 
Usefulness  
 
The aim of the study is to increase knowledge about function, quality of life and risk of 
developing osteoarthritis after femoral lengthening. it is of importance for both patients and 
clinicians to be aware of possible long-term consequences of the treatment. All patients that 

are treated with femoral lengthening at Oslo University Hospital nowadays, are close 
monitored by physiotherapist first in hospital care, and then locally after discharge. As there is 
lack of available research on the field, our results can be of interest for both patients, 
orthopedists, physiotherapists and other health care professionals.  
 
Approvals and registrations 
 
- 
Regional ethics committee: 2018/416 REK South East B. 
- 
Data protection officer at Oslo University Hospital: 18/08589. 
- 
Radiographic section at Oslo University Hospital: 1829. 
- 
ClinicalTrials.gov: NCT03966573. 
 
 
 
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